Tag Archives: Subchondroplasty

Subchondroplasty in the lower extremity: A literature review

by Steven Cooperman, DPM1*; Thomas Yates, DPM1; David Shofler, DPM, MSHS1

The Foot and Ankle Online Journal 13 (3): 8

Osteoarthritis is one of the most common and debilitating conditions encountered by foot and ankle surgeons. This osteoarthritis is often accompanied by a coinciding bone marrow lesion (BML) which has been shown to result in poorer patient outcomes. The subchondroplasty procedure was developed with the aim of targeting these painful BMLs in order to slow the progression of osteoarthritic changes. There has been a trend in both orthopedic and podiatric literature towards the use of this procedure in the lower extremity. This review is meant to bring forward the information most pertinent to the procedure to help inform the foot and ankle surgeon of its uses and potential, as well as to encourage future research into the procedure.

Keywords: subchondroplasty, bone marrow lesion, osteoarthritis, calcium phosphate, bone substitute material

ISSN 1941-6806
doi: 10.3827/faoj.2020.1303.0008

1 – Department of Podiatric Medicine, Surgery, and Biomechanics, Western University College of Podiatric Medicine, 309 E 2nd Street, Pomona, CA 91766
* – Corresponding author: Scooperman@westernU.edu

Osteoarthritis (OA) remains one of most common and debilitating conditions encountered by foot and ankle surgeons. Whether the result of trauma or degenerative overuse, orthopedic and podiatric surgeons alike can agree that the sequelae of OA can be challenging to manage. The natural history of OA involves persistent joint pain, lack of normal function, and can include a vicious cycle which may progress to osteonecrosis of the affected bones. While the current body of evidence of in vitro cartilage repair and regenerative medicine is rapidly growing, there are perhaps other more readily available methods of treating OA which may ultimately demonstrate equal benefit to patients. Subchondroplasty® (SCP) (Zimmer Knee Creations, West Chester, PA) is a surgical system, developed in 2007, in which flowable bone substitute material (BSM) is injected into subchondral bone in order to fill a defect. The procedure acts to support the subchondral bone layer by providing a scaffold over which new, healthier osteochondral elements may be produced [1]. Although this technique has primarily been described in literature to treat bone marrow lesions (BMLs) in the knee joint, this technique has recently been applied to the foot and ankle with comparably successful outcomes.

This paper is not meant to serve as a technique guide, but a review of available relevant literature. As such, the use of the term subchondroplasty throughout the paper will be in reference to the procedure itself, not the proprietary system. The goal of this review is to benefit the foot and ankle surgeon by: first, providing a general understanding of the procedure and its expanding applications; second, by presenting the largely positive patient outcomes in both the orthopedic and podiatric literature in an attempt to encourage further study into a relatively new – yet promising – tool in the foot and ankle surgeon’s array of treatments.


An extensive search of available literature related to: 1) subchondral bone and the osteochondral unit; 2) lower extremity osteoarthritis; 3) bone substitute materials; 4) the subchondroplasty procedure, including its related radiographic findings and clinical outcomes in the lower extremity.


Within joints, the subchondral bone layer is a supporting structure for the overlying articular cartilage. Subchondral bone is an underappreciated, yet vital component to the function of each osteochondral unit and overall joint health [2]. Bone metabolism is dynamic, in concert with Wolff’s law, and a normal subchondral bone plate displays the same capacity to increase in thickness according to physiologic loading [3].

In osteoarthritis, this typically dynamic nature of the subchondral bone plate is disrupted. Increased and imbalanced dispersion of joint forces, combined with a concentration of stresses and synovial fluid infiltration into the subchondral bone, can lead to reduced healing capacity and abnormalities within the underlying cancellous bone. These abnormalities can be identified both histologically and on magnetic resonance imaging (MRI) as bone marrow lesions (BMLs) [4-7].

The mechanism of coinciding pain associated with these BMLs is currently under debate, but has been attributed to the healing response secondary to trauma and trabecular injury and/or impaired venous drainage [8-10]. Histologically, BMLs have been shown to be focal areas of demineralization, increased fibrosis, and vascular abnormalities. These abnormalities can mimic chronic stress fractures, which may then progress to areas of focal necrosis [6,11-15]. Clinically, it is of great importance that BMLs be identified and treated, as they have been linked to increased arthritic pain and may hasten the progression of joint deterioration [5,16-18].

These potential consequences have been attributed to both improper load transmission across the affected joints and an underlying imbalance in bone metabolism––favoring bone resorption when a BML is present [19]. A direct correlation between increasing size of BMLs and increased pain in the knee was identified in a study by Felson, et al., in 2007. Patients experiencing pain were found to have a 3.31-fold greater likelihood of significant findings on MRI compared to non-painful patients with the same radiologic degree of arthrosis [20]. Additionally, Saltzman and Kijowski found that BML prevalence, depth, and cross-sectional area under arthroscopy were each directly correlated with worsening grades of corresponding articular cartilage defects [2,21].

Osteoarthritis occurring in the hip and knee joints primarily occurs as a degenerative process. However, due to histological, anatomic, and biomechanical differences in the cartilage of the ankle joint, arthritis in the ankle most commonly occurs after significant trauma [22-24]. Due to the post-traumatic presentation of ankle joint arthritis, there exists a propensity for a wider range of ages at which osteoarthritis may present in the affected ankle, which has important implications with how these patients are definitively treated. Younger and more active patients with ankle joint arthritis are less tolerant of arthrodesis or arthroplasty procedures than are their elderly and less active counterparts. As such, it stands to reason that there should be a great deal of interest in the potential for joint sparing procedures in these patients.

The Procedure

In this procedure, BMLs are triangulated using fluoroscopy, and subsequently injected and filled with flowable, biologically-compatible ceramic materials. The injected bone substitute material (BSM) then undergoes an endothermic reaction, resulting in crystallization of the BSM which affords properties similar to that of cancellous bone. This is believed to assist in supporting the trabecular structure of the bone, and to slow or even halt the pathologic processes at work. Typically, this procedure has been performed with calcium phosphate (CaP), calcium sulfate (CaS) or hydroxyapatite (HA), with CaP being the more commonly used of the three [25]. However, in terms of osteobiology, these products only offer one component of the osteobiology triad: osteoconduction. As such, these products only function as a scaffolding upon which healing may take place.

In 2016, Hood et al proposed that the two remaining osteobiologic properties, osteogenesis and osteoinduction, could be imparted via the addition of bone marrow aspirate concentrate (BMAC) to the osteoconductive materials used during the procedure [25]. It had previously been shown that osseous regeneration occurs at a faster rate with the use of a combination of BMA and osteoconductive ceramic materials, as opposed to either alone [26]. The premise behind this is that replacing the 0.9% normal saline solution (NSS)––which is typically used for rehydration of the bone substitute material––with autogenous BMAC, bone healing potential can be improved.

The addition of BMACs, the osteoconductive CaP would have the theoretical benefit of mesenchymal stem cells (MSCs), osteoprogenitor cells (OPCs), hematopoietic stem cells (HSCs), platelets, vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-β) to assist in the reparative process [26-29]. In patients with concomitant cartilaginous defects, particulated juvenile allograft cartilage (PJAC) can be used to address the overlying cartilaginous defect after hardening of the CaP scaffold [8].

Hood et al. presented a case report for a 26 year old female with two years of recalcitrant left ankle pain after a motor vehicle accident. This patient eventually underwent the modified SCP® technique with rehydration using BMAC for a talar dome BML [25]. It was reported that the patient’s pain decreased from a preoperative VAS score of 9 to occasional 1-2/10 discomfort at 6 weeks postoperatively.

CaP with BMAC has since become a popular choice among bone and joint surgeons, though other orthobiologic combinations have also been reported with promising results: CaS with platelet-rich plasma (PRP), HA with BMAC, and HA-tri-CaP with MSC [30-32]. Subsequent studies have aimed to clarify the following: the ideal osteoinductive/osteogenic adjunct, the proper amount and consistency of adjunct, the effect on curing time and handling, and the adjunct’s effect on the scaffolding material.

In 2015, Colon et al. evaluated in vitro injectability of common commercially available bone substitute materials (BSMs). Histologically, bone marrow lesions (BMLs) demonstrate micro-trabecular damage characteristic of stress fractures [15]. For injection of materials into these microtrabeculae to be considered possible, the materials must have the ability to be injected into a highly pressurized space. Eight of the most common commercially available BSMs were tested (AccuFill® (Zimmer, Inc.), Beta-BSM™ (Zimmer, Inc.), Cerament™ (Biomet, Inc.), HydroSet™ (Styker®), Norian™ SRS (DePuy Synthes®), Pro-Dense® (Wright Medical Inc.), StrucSure™ CP (Smith & Nephew plc), Simplex™ (Stryker®)) using the polyurethane block material, while three were additionally tested in femoral condyle cadaveric bone blocks from healthy donors (AccuFill®, Beta-BSM™ and StrucSure™). The results found that although these materials are all considered injectable BSMs, only three were able to flow into the closed structure of the polyurethane block (AccuFill®, Simplex™ and StrucSure™). Additionally, AccuFill® was shown to outperform the other BSMs in several areas: the ability to flow within micro-architecture without damage from the applied force, the lowest injection force, the highest volume injected, the greatest area covered by material injected, and the ability to set without an exothermic reaction. The knowledge that these commercial calcium phosphate (CaP) products have differing properties, and understanding how this may affect different aspects of the procedure, can help inform the decision making of the surgeon.


In 2016, Agten, et al., and Nevalainen, et al., both published papers describing diagnostic imaging related to the subchondroplasty procedure in the knee. The goal was to educate radiologists and familiarize them with expected post-procedure findings. Agten, et al., reviewed the pre- and postoperative imaging for nine patients, with the first postoperative imaging at three months post-operatively. Nevalainen, et al., discussed two knee subchondroplasty case studies. Preoperative imaging revealed that insufficiency fracture was associated with a greater amount of bone marrow edema than osteoarthritis [33].

Following the procedure, postoperative radiographs should display an increased radiodensity at the site of calcium phosphate injection, which should correlate with the locations of bone marrow edema (BME) on preoperative imaging [33,34]. CaP extravasation into soft tissues may occur along the track of the injection, which predictably mimics the appearance of heterotopic ossification. Extra-articular extravasation of calcium phosphate may resolve over time, while intra-articular leakage is a complication that should be addressed intraoperatively.

When evaluating patients, it is important to identify the cause of bone marrow edema, as this is a relatively non-specific finding, particularly on MRI. Trauma, including bone contusions, is the most common cause of positive BME findings on MRI [35]. The remaining causes of BME on MRI are transient BME syndromes (including transient osteoporosis, regional migratory osteoporosis, and complex regional pain syndrome), repetitive microtrauma and stress fractures, and non-traumatic causes such as avascular necrosis, spontaneous osteonecrosis, reactive polyarthritis, and neoplasms [2].

Classic findings of BMLs include a focal area of BME appearing as high signal intensity on T2-weighted, fat-saturated images and low signal intensity on T1-weighted, fat sensitive images. The increased signal intensity of BMLs on T2-weighted, fat-saturated MRI sequences has been suggested to be a result of increased subchondral vascularity [1]. Additionally, a low-signal-intensity line in the subchondral region of T2-weighted, fat-saturated images may be present, corresponding to impaction of the trabecular bone [35]. If present, it has been shown that a length and thickness of this line greater than 14mm and 4mm, respectively, are risk factors for lesion progression and subchondral collapse [36]. This signal should change to a decreased signal intensity on both T1-weighted fat-sensitive and T2-weighted fat-saturated images following injection of the CaP [33,34]. On fat-saturated, fluid-sensitive images there may also be a fine rim of increased signal intensity surrounding the CaP, representing surrounding edema [33,34]. It should be noted that a direct correlation between increasing BME signal intensity and more advanced cartilage degradation on MRI has also been identified [37].

Preoperative CT scan may be useful in conjunction with MRI, especially in the case of concurrent cartilage injury, as this can be difficult to assess on MRI [38,39]. Concurrent evaluation of the cartilage portion of the osteochondral unit should be considered of utmost importance, as 60% of patients with surgically confirmed chondral degeneration in the knee have been shown to have associated BMLs [21]. Additionally, both cartilage thinning and bony edema can lead to over- or underestimation of cartilage and bone damage on MRI [40]. Postoperatively on CT scan, any drill holes will be seen as a hypodense track with the surrounding hyperdense CaP [33].

Notably, the changes described correlating to post-procedure imaging have been shown to regress over time. Still, the specific time-frame is currently unclear and likely variable. In canine models, the majority of BSM has been found to be absorbed by two years postoperatively [41].

Use for OA/BML in the knee

Subchondroplasty was originally described for use in the treatment of moderate to severe osteoarthritic knee pain present for more than 2-6 months, with concomitant presence of a BML localized to the area of pain [42]. The presence of a BML in these patients is particularly concerning, as patients with knee OA compounded with a BML have a highly predictable progression to total knee arthroplasty (TKA). In fact, this occurs approximately nine times more frequently over a three year period when compared to OA in patients without a coinciding BML [4,43-45]. Previous treatment of cartilaginous defects in the knee by arthroscopic debridement alone has not been shown to yield success for patients suffering from moderate to end stage osteoarthritis, with several studies showing either no improvement or minor improvement at six months, and no improvement at two years. [4,45-48].

In 2016, a study by Cohen, et al., evaluated the combined treatment of subchondroplasty and arthroscopy in the knee in 66 patients who initially presented for TKA consultation [4]. Pain was significantly decreased and function significantly improved in all groups, including at both 6 and 24 months post-op. Notably, there was a 70% 2-year joint preservation survivorship. Patients who ultimately received TKA were significantly older and were more likely to have had a history of prior meniscectomy. A follow-up study from Brazil also noted positive results, with improvement on both VAS and knee injury and osteoarthritis outcome scores (KOOS) at 24 weeks postoperatively [14]. Longer-term outcomes of treatment with CaP in post-traumatic, impact-induced BMLs in a medial femoral condyle canine model have also shown symptomatic and functional benefits for up to two years [41].

The effect on TKA

Logically, the next question to address is whether the technique of treating BML using CaP bone substitutes affects outcomes in patients who fail this joint preserving technique and require knee replacement. It has previously been reported that the complexity of knee arthroplasty increases in patients who have had previous knee surgery, resulting in the potential for more complications and poorer outcomes [49-52]. In 2016, Yoo, et al., evaluated the effect of prior BML treatment on the complexity and outcomes of future knee arthroplasty procedures [53]. A total of 22 patients who had undergone prior arthroscopic repair of BMLs were demographically matched in a 1:2 ratio to a group of controls undergoing knee arthroplasty, either unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). Patients were followed up for an average of 23.5 months (ranging from 12-52 months), with no significant differences identified between the groups. There were no cases of intra-operative UKA conversion to TKA, no differences in surgical complications or technical challenges between groups, and no cases of non-standard primary components required. Additionally, on intraoperative inspection of the CaP bone substitute, it was reported to be consistently well incorporated without signs of compromise or inconsistencies from the subchondral bone. Based on their findings, Yoo, et al., concluded that previous treatment of BMLs using CaP bone substitute did not compromise knee arthroplasty outcomes or surgical performance.

Functional/Subjective outcomes in the knee

Functional and subjective outcomes have been generally favorable following subchondroplasty. In 2018, a literature review of 8 articles and 164 total patients treated with CaP injection for BMLs in the femoral condyles or tibial plateau noted significant improvement in symptoms, few complications, and return to activity at an average of three months [42]. Of the articles reviewed, only a single paper reported a subgroup of patients who experienced poor outcomes from the procedure. Chatterjee, et al., identified an inverse relationship between the subjective postoperative Tegner-Lysholm knee scoring scale and preoperative Kellgren-Lawrence osteoarthritis grade [54]. In other words, a correlation was identified between poorer subjective outcomes and more severe preoperative osteoarthritis. Despite this, other studies have failed to report similar correlation between OA grade and outcomes. As such, future prospective studies would be valuable in confirming this finding.

Described use in the Foot and Ankle

At this time, the literature regarding treatment of BMLs using flowable calcium phosphate (CaP) has been primarily directed to cases in the knee. However, due to the need for joint-sparing procedures for ankle osteoarthritis and for the treatment of symptomatic BMLs, there has been growing interest in its application in the foot and ankle. Since subchondroplasty was first introduced into the field of foot and ankle surgery in 2015, more than six thousand foot and ankle subchondroplasty procedures have been performed [55]. The first reported subchondroplasty procedures performed in the foot and ankle were from Miller, et al., [56]. Two cases were reported, the first in a 48 year old male with complaints of chronic left ankle pain and instability, and the second in a 28 year old male with chronic ankle pain following a fibular non-union. In both cases, the patients exhibited talar BMLs on MRI that were recalcitrant to conservative treatments. Each patient underwent a subchondroplasty procedure, combined with other indicated procedures. The first patient was able to return to full activity at 12 weeks post-operatively, while the second sustained a tibial fracture due to a syncopal event at 13 weeks post-op. Miller, et al., reported minimal subjective pain in both cases at 10-month follow-up with no activity restrictions.

Shortly thereafter in 2018, Chan, et al., reported an 11-patient retrospective cohort study of symptomatic talar osteochondral defects (OCDs) treated with subchondroplasty with bone marrow aspirate concentrate (BMAC) injection [57]. In this cohort, the mean talar OCD size was 1.3 cm x 1.4 cm. All subjective outcomes improved from preoperative baseline to final one year follow-up, including visual analog pain scale and Foot and Ankle Outcome Score, with 10 out of the 11 patients reporting they would undergo the procedure again. There was a single reported complication in the cohort, with a talar neck stress fracture at bone-BSM interface after the patient had previously experienced full resolution of symptoms. All patients, except for the aforementioned complication, returned to full activity between three and nine weeks postoperatively.

Barp, et al., published two case reports, including a 25 year-old male tennis player and a 53 year-old female, treated with percutaneous injection of CaP into the 2nd metatarsal head (Frieberg’s infraction) and cuboid (stress fracture), respectively. Both patients were allowed protected weightbearing as tolerated at one week postoperatively, returned to full activity without pain at four weeks, and remained free of related complaints at final follow-up at one and three years, respectively [58].

BMLs in the foot have also been found to be associated with plantar fasciitis, specifically patients requiring surgical intervention [59]. This may have significant clinical implications. In a report by Bernhard, et al., a single case of recalcitrant plantar fasciitis was shown to have a concomitant calcaneal BML on MRI [60]. This patient was treated with repeat plantar fasciotomy and CaP injection of the BML, successfully resulting in full return to activity and pain-free follow-up at 3 and 10 months.


Perhaps due to the minimally invasive nature of the procedure, few complications of subchondroplasty have been reported in the literature. While rare, the surgeon should be aware of the following potential complications: pain secondary to overfilling with CaP, intra- or extra-articular extravasation of CaP, deep vein thrombosis of the operative limb, subsequent soft tissue or bone infection, stress fracture at the bone-BSM interface, and avascular necrosis [8,57,61].

Pain secondary to overfilling with CaP has been identified as the most common complication of the subchondroplasty procedure, and has been described clinically as a disproportionate pain which often resolves completely within 72 hours postoperatively [42]. Over-pressurization and failure to completely fill a BML have both been associated with poorer outcomes in the orthopedic knee literature and are highly preventable with increased surgeon experience [62]. A single case of osteomyelitis secondary to subchondroplasty in the medial femoral condyle was reported by Dold, et al. In their report, the authors considered that this procedure may have a predisposition for infectious complications due to direct seeding and the hydrophilic nature of CaP, which can result in prolonged wound drainage, poor healing, and eventual sinus tract formation [61]. In a series of 11 patients receiving CaP injection in the talus for painful osteochondral defects, Chan, et al., reported a single complication in a patient with a BMI of 34 kg/m² who experienced a talar neck stress fracture at the bone-BSM interface [57].


Overall, subchondroplasty for the treatment of BMLs has led to promising outcomes and infrequent complications. The range of potential applications of the technique is constantly expanding, with increasing use in the treatment of foot and ankle pathology. Additional studies may help clarify the potential benefits in the setting of osteoarthritis of the foot and ankle, including the procedures potential in delaying and/or preventing total ankle arthroplasty.


  1. Pelucacci LM, LaPorta GA. 2018. Subchondroplasty: treatment of bone marrow lesions in the lower extremity. Clin Pod Med Surg 35: 367-371.
  2. Saltzman BM, Riboh JC. 2018. Subchondral bone and the osteochondral unit: basic science and clinical applications in sports medicine. Sports Health, 10(5): 412-418.
  3. Duan CY, Espinoza Orias AA, Shott S, et al. In vivo measurement of the subchondral bone thickness of lumbar facet joint using magnetic resonance imaging. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. 2011;19(1):96–102.
  4. Cohen SB, Sharkey PF. 2016. Subchondroplasty for treating bone marrow lesions. J Knee Surg, 29: 555-563.
  5. Roemer FW, Neogi T, Nevitt MC, et al. Subchondral bone marrow lesions are highly associated with, and predict subchondral bone attrition longitudinally: the MOST study. Osteoarthritis Cartilage 2010;18:47-53.
  6. Farr J, Cohen SB. Expanding applications of the subchondroplasty procedure for the treatment of bone marrow lesions observed on magnetic resonance imaging. Oper Tech Sports Med 2013; 21:138–143.
  7. Van Dijk CN, et al. 2010. Osteochondral defects in the ankle: why painful? Knee Surg Sports Traumatol Arthro, 18: 570-580.
  8. Ng A, et al. 2017. Advances in ankle cartilage repair. Clin Pod Med Surg, 34: 471-487.
  9. Eriksen EF, Ringe JD. Bone marrow lesions: a universal bone response to injury? Rheumatol Int 2012;32(3):575–84.
  10. Arnoldi CC, Djurhuus JC, Heerfordt J, Karle A. Intraosseous phlebography, intraosseous pressure measurements and 99m Tc-polyphosphate scintigraphy in patients with various painful conditions in the hip and knee. Acta Orthop Scand. 1980;51:19-28.
  11. Zanetti M, et al. 2000. Bone marrow edema pattern in osteoarthritic knees: correlation between MR imaging and histologic findings. Radiology, 215: 835–840.
  12. Hunter DJ, Gerstenfeld L, Bishop G, et al. Bone marrow lesions from osteoarthritis knees are characterized by sclerotic bone that is less well mineralized. Arthritis Res Ther 11:R11, 2009.
  13. Taljanovic MS, Graham AR, Benjamin JB, et al. Bone marrow edema pattern in advanced hip osteoarthritis: quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology. Skeletal Radiol 37:423-431, 2008.
  14. Bonadio MB, et al. 2017. Subchondroplasty for treating bone marrow lesions in the knee: initial experience. Revista Brasileira de Ortopedia, 52(3): 325-330.
  15. Colon DA, et al. 2015. Assessment of the injection behavior of commercially available bone BSM’s for subchondroplasty procedures. The Knee, 22: 597-603.
  16. Wluka AE, et al. 2008. Bone marrow lesions predict progression of cartilage defects and loss of cartilage volume in healthy middle aged adults without knee pain over 2 years. Rheum, 47(9): 1392-1396.
  17. Felson DT, Chaisson CE, Hill CL, et al. The association of bone marrow lesions with pain in knee osteoarthritis. Ann Intern Med 2001;134:541-549.
  18. Link TM, Steinbach LS, Ghosh S, et al. Osteoarthritis: MR imaging findings in different stages of disease and correlation with clinical findings. Radiology. 2003;226:373-381.
  19. Sharkey PF, Cohen SB, Leinberry CF, Parvizi J. Subchondral bone marrow lesions associated with knee osteoarthritis. Am J Orthop. 2012;41(9):413-417.
  20. Felson DT, Niu J, Guermazi A, et al. Correlation of the development of knee pain with enlarging bone marrow lesions on magnetic resonance imaging. Arthritis Rheum 2007; 56:2986–2992.
  21. Kijowski R, Stanton P, Fine J, De Smet A. Subchondral bone marrow edema in patients with degeneration of the articular cartilage of the knee joint. Radiology. 2006;238:943-949.
  22. Kraeutler MJ, Kaenkumchorn T, Pascual-Garrido C, et al. Peculiarities in ankle cartilage. Cartilage 2017;8(1):12–8.
  23. Millington SA, Grabner M, Wozelka Mag R, et al. Quantification of ankle articular cartilage topography and thickness using a high resolution stereophotography system. Osteoarthritis Cartilage 2007;15:205–11.
  24. Shepherd DE, Seedhom BB. Thickness of human articular cartilage in joints of the lower limb. Ann Rheum Dis 1999;58:27–34.
  25. Hood CR, Miller JR. 2016. The triad of osteobiology: rehydrating calcium phosphate with bone marrow aspirate concentrate for the treatment of bone marrow lesions. Foot Ankle Online, 9(1): 11.
  26. Block JE. The role and effectiveness of bone marrow in osseous regeneration. Med Hypotheses. 2005;65(4):740-747. doi:10.1016/j.mehy.2005.04.026.
  27. Sampson S, Botto-van Bemden A, Aufiero D. Autologous bone marrow concentrate: review and application of a novel intra-articular orthobiologic for cartilage disease. Physician Sport Med. 2013;41(3):718. doi:10.1007/s13398-014-0173-7.2.
  28. Ishihara A, Helbig HJ, Sanchez-Hodge RB, Wellman ML, Landrigan MD, Bertone AL. Performance of a gravitational marrow separator, multidirectional bone marrow aspiration needle, and repeated bone marrow collections on the production of concentrated bone marrow and separation of mesenchymal stem cells in horses. Am J Vet Res. 2013;74(6):854-863.
  29. Khan WS, Rayan F, Dhinsa BS, Marsh D. An osteoconductive, osteoinductive, and osteogenic tissue-engineered product for trauma and orthopaedic surgery: how far are we? Stem Cells Int. 2012:1-7. doi:10.1155/2012/236231.
  30. Intini G, Andreana S, Intini FE, Buhite RJ, Bobek LA. Calcium sulfate and platelet-rich plasma make a novel osteoinductive biomaterial for bone regeneration. J Transl Med. 2007;5(13):1-13. doi:10.1186/1479-58765-13.
  31. Torres K, Lopes A, Lopes M, et al. The benefit of a human bone marrow stem cells concentrate in addition to an inorganic scaffold for bone regeneration: an in vitro study. Biomed Res Int. 2015;2015:1-10. doi:10.1155/2015/240698.
  32. Tshamala M, Bree H Van, Animals D. Osteoinductive properties of the bone marrow–myth or reality. Vet Comp Orthop Traumatol. 2006;19(3):133-141.
  33. Agten CA, et al. 2016. Subchondroplasty: what the radiologist needs to know. Amer J Rad, 207: 1257-1262.
  34. Nevalainen MT, et al. 2016. MRI findings of subchondroplasty of the knee: a two-case report. Clin Imaging, 40: 241-243.
  35. Bonadio MB, et al. 2017. Bone marrow lesion: image, clinical presentation, and treatment. Magn Res Insights, 10: 1-6.
  36. Lecouvet FE, van de Berg BC, Maldague BE, et al. Early irreversible osteonecrosis versus transient lesions of the femoral condyles: prognostic value of subchondral bone and marrow changes on MR imaging. AJR Am J Roentgenol. 1998;170:71–77.
  37. Zhao J, et al. 2010. Longitudinal assessment of bone marrow edema-like lesions and cartilage degeneration in osteoarthritis using 3 T MR T1rho quantification. Skeletal Radiol, 39: 523-531.
  38. Barr C, Bauer JS, Malfair D, et al. MR imaging of the ankle at 3 Tesla and 1.5 Tesla: protocol optimization and application to cartilage, ligament and tendon pathology in cadaver specimens. Eur Radiol. 2007;17(6):1518-1528.
  39. Hembree WC, Wittstein JR, Vinson EN, et al. Magnetic resonance imaging features of osteochondral lesions of the talus. Foot Ankle Int. 2012;33(7):591-597.
  40. Nakasa T, et al. 2018. Evaluation of articular cartilage injury using computed tomography with axial traction in the ankle joint. Foot Ankle Int’l, 39(9): 1120-1127.
  41. Brimmo OA, et al. 2018. Subchondroplasty for the treatment of post-traumatic bone marrow lesions of the medial femoral condyle in a pre-clinical canine model. J Ortho Res, 36: 2709-2717.
  42. Astur DC, et al. 2018. Evaluation and management of subchondral calcium phosphate injection technique to treat bone marrow lesion. Cartilage: 1-7.
  43. Tanamas SK, Wluka AE, Pelletier JP, et al. Bone marrow lesions in people with knee osteoarthritis predict progression of disease and joint replacement: a longitudinal study. Rheumatology (Oxford) 2010;49(12):2413–2419.
  44. Scher C, Craig J, Nelson F. Bone marrow edema in the knee in osteoarthrosis and association with total knee arthroplasty within a three-year follow-up. Skeletal Radiol 2008;37(7):609–617.
  45. Kröner AH, Berger CE, Kluger R, Oberhauser G, Bock P, Engel A. Influence of high tibial osteotomy on bone marrow edema in the knee. Clin Orthop Relat Res 2007;454(454):155–162.
  46. Moseley JB, O’Malley K, Petersen NJ, et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2002;347(2):81–88 15.
  47. Kirkley A, Birmingham TB, Litchfield RB, et al. A randomized trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2008;359(11):1097–1107, 16.
  48. Thorlund JB, Juhl CB, Roos EM, Lohmander LS. Arthroscopic surgery for degenerative knee: systematic review and metaanalysis of benefits and harms. BMJ 2015;350:h2747.
  49. Lizaur-Ultrilla A, Collados-Maestre I, Miralles-Munoz FA, et al. Total knee arthroplasty for osteoarthritis secondary to fracture of the tibial plateau. A prospective matched cohort study. J Arthroplasty 2015;30:1328.
  50. Klit J. Results of total joint arthroplasty and joint preserving surgery in younger patients evaluated by alternative outcome measures. Dan Med J 2014;61(4):B4836.
  51. Bastos Filho R, Magnussen RA, Duthon V, et al. Total knee arthroplasty after high tibial osteotomy: a comparison of opening and closing wedge osteotomy. Int Orthop 2013;37(3):427.
  52. Haslam P, Armstrong M, Geutjens G, et al. Total knee arthroplasty after failed high tibial osteotomy long-term follow-up of matched groups. J Arthroplasty 2007;22(2)245.
  53. Yoo JY, et al. 2016. Knee arthroplasty after subchondroplasty: early results, complications, and technical challenges. J Arthroplasty, 31: 2188-2192.
  54. Chatterjee D, McGee A, Strauss E, Youm T, Jazrawi L. Subchondral calcium phosphate is ineffective for bone marrow edema lesions in adults with advanced osteoarthritis. Clin Orthop Relat Res 2015; 473: 2334–2342.
  55. McWilliams GD, et al. 2019. Subchondroplasty of the ankle and hindfoot for treatment of osteochondral lesions and stress fractures. Foot Ankle Spec, doi:
  56. Miller JR, Dunn KW. 2015. Subchondroplasty of the ankle: a novel technique. Foot Ankle Online, 8(1):7.
  57. Chan JJ, et al. 2018. Safety and effectiveness of talus subchondroplasty and bone marrow aspirate concentrate for the treatment of osteochondral defects of the talus. Ortho, 41(5): 734-737.
  58. Barp EA, et al. 2019. Subchondroplasty of the foot: two case reports. JFAS, 58: 989-994.
  59. Grasel RP, Schweitzer ME, Kovalovich AM, Karasick D, Wapner K, Hecht P, Wander D. MR imaging of plantar fasciitis: Edema, tears, and occult marrow abnormalities correlated with outcome. AJR Am J Roentgenol 173:699–701, 1999.
  60. Bernhard K, et al. 2018. Surgical treatment of bone marrow lesion associated with recurrent plantar fasciitis: a case report describing an innovative technique using subchondroplasty. JFAS, 57: 811-815.
  61. Dold AP, et al. 2017. Osteomyelitis after calcium phosphate subchondroplasty. Bulletin Hosp Joint Disease, 75(4): 282-285.
  62. Saltzman BM, Oliver-Welsh L, Yanke AB, Cole BJ. Subchondroplasty. In: Miller MD, Cole BJ, Cosgarea A, Owens BD, Browne JA, eds. Operative Techniques: Knee Surgery. 2nd ed. Philadelphia, PA: Elsevier; 2018:152-156.



The triad of osteobiology – Rehydrating calcium phosphate with bone marrow aspirate concentrate for the treatment of bone marrow lesions

by Christopher R. Hood JR., DPM, AACFAS1*, Jason R. Miller, DPM, FACFAS2pdflrg

The Foot and Ankle Online Journal 9 (1): 11

The topic of bone marrow lesions has been more widely discussed in recent years, especially in the knee literature. One such procedure to treat this pathology is back-filling the lesion with bone substitute materials, calcium phosphate (CaP), as just one example. This technique uses the principle of osteoconduction, CaP mimicking the composition of subchondral bone and creating a scaffold for bone cells to integrate onto and promote internal cancellous bone healing. After performing this procedure on the foot and ankle as the protocol describes, a technique was developed to increase healing potential by adding concentrated bone marrow aspirate (BMA) to the CaP. This addition in theory gives us increased osteobiology properties – osteogenesis, osteoconduction, and possibly osteoinduction through growth factors like transforming growth factor beta (TBF-β) and vascular endothelial growth factor (VEGF). Based off of other reported literature, this technique has theoretical benefit in the operating room to increase patient results. Here the method is discussed with a case example.

Key words: BioCUETM, bone marrow lesion, bone marrow aspirate (BMA), calcium phosphate (CaP), osteogenesis, osteoconductive, osteoinductive, Subchondroplasty®

ISSN 1941-6806
doi: 10.3827/faoj.2016.0901.0011

1 – Post-Graduate Fellow, Pennsylvania Intensive Lower Extremity Fellowship, Premier Orthopaedics and Sports Medicine, Malvern, PA
2 – Fellowship Director, Premier Orthopaedics and Sports Medicine, Malvern, PA and Residency Director, Phoenixville Hospital PMSR/RRA, Phoenixville, PA
* – Correspondence: crhoodjr12@gmail.com

Bone marrow lesions (BML) first correlation to knee pain and osteoarthritis was cited by Felson et al in 2001 [1,2]. In a magnetic resonance imaging (MRI) study, 77.5% of participants with knee pain had evidence of BMLs, represented as an increased area of T2-weighted image signal intensity adjacent and deep to the subchondral bone plate. This represents a pathologic event of blood or fluid accumulation (synovial, water), resulting in an intraosseous increase in pressure [1]. Repetitive loading to the joint prevents healing, with the creation of bone infarcts, cartilage breakdown, and chronic pain.

One way to assist in healing is through filling these lesions with biologic materials to promote bone growth in order to restore the damaged subchondral architecture. Sometimes considered insufficiency fractures or non-healing/non-union fractures, surgeons have been searching for a technique to internally support these BMLs and stop the pathological process. This is the principle behind the Subchondroplasty® (Zimmer Knee Creations, Exton, PA) (SCP®) technique, targeted filling of the BML with a nanocrystal calcium phosphate (CaP) bone substitute material.

Osteoconductive materials such as CaP, calcium sulfate (CaS), or hydroxyapatite (HA) have been used to treat various osseous pathology. Each synthetic bone filling substitute has its own indication whether pure bone void filling versus structural support to a load-bearing bone is required. Regardless, the goal is to restore the natural osseous biology as effectively and efficiently as possible.  However, many of these commercial products only deliver one of the key components of osteo-restoration: osteoconduction through acting as a scaffold for innate cells to respond to and remodel.  Here we demonstrate a technique of enhancing the biology through adding osteogenic and possibly osteoinductive growth factor potential through incorporating bone marrow aspirate (BMA) concentrate (BMAC) [3-6]. Based on previous work, we suspect this combination leads to greater biological healing and restoration of the cancellous bone in the BML [5-8].

Design Rationale (Use of BMAC/CaP Rationale)

The SCP® technique for repair of BMLs consists of filling the lesions with AccuFill® Bone Substitute Material (Zimmer Knee Creations, Exton, PA), a proprietary formulation of a highly-porous nanocrystalline CaP structure. This product acts as a point of internal fixation, providing support for osteoblast in-growth.  The protocol requires its’ rehydrated with 0.9% normal saline solution (NSS). Based on previously published literature, it was proposed in order to increase host response and healing potential, an autogenous BMAC flowable tissue could replace the NSS for rehydrating the CaP [5,7,8].

Bone marrow is aspirated to concentrate the cells contained within to augment and advance tissue repair, in this instance for bone regeneration. The target cells in bone marrow consist of the mesenchymal stem cells (MSCs), progenitor cells, hematopoietic stem cells (HSCs) and platelets [3,4,7]. The MSC differentiate into osteoprogenitor (OPG) cells, which further differentiate into osteoblasts (bone forming cells) with the assistant of growth factor signaling while the HSCs and platelets provide the important growth factors like transforming growth factor beta (TGF-β), platelet derived growth factor (PDFG), and vascular endothelial growth factor (VEGF) [4]. The use of BMA with ceramic materials has been cited in the past as a marrow-impregnated graft. Reports have cited faster and more consistent defect healing compared to either product used individually [7]. Examples of use include bone defects (post-traumatic, iatrogenic), cysts, and tumors. It is felt a synergistic effect takes place, BMA supplying the OPG cells which stay locally attached to the CaP scaffold for in-growth and mineralization to take place upon [9]. There have been reports of combining CaS and platelet-rich plasma (PRP) with good results [10]. It is this theory which we base our technique upon. By altering or “up-regulating” the healing/recovery potential, we feel this more biologically active local environment leads to quicker and more robust healing response. The introduction of BMAC adds osteogenic cells and growth factors to the osteoconductive CaP environment to create increased osteobiology for optimal healing potential. This composite provides an alternative to the ‘gold standard’ autograft with a much more minimalist approach in the harvesting technique [9].

Surgical Technique

The basis of patient evaluation and work up for BML with SCP® intervention has been previously described by the senior author (J.R.M.) for foot and ankle pathology, although the indications are similar for other joints [2,11]. This should be reviewed to understand the theory behind and technique involved in performing SCP®. Once the decision has been made for treatment by SCP®, the described technique can be used to augment the normal process.

SCP® involves preparation of the injectable CaP bone substitute AccuFill® for placement into the BML through provided cannulated drills. These drills come in two sizes (11 and 15 gauge) and have two tip configurations in the larger size (end delivery and side-port delivery). The kit includes 5-cc of CaP powered that requires rehydration with 3.0-3.2-cc of the provided NSS. The two components are mixed until a putty that posses a toothpaste-like consistency is achieved. The mixing component of the procedure is surgeon preference, wanting to obtain the “right” consistency; too thin and it will not appropriately dry and harden while too thick and it will be difficult to inject and working time is decreased. It may take multiple procedures to get a feel for the product and therefore new surgeons to the procedure are cautioned to slowly rehydrate (drop-by-drop) the CaP once 3-cc of NSS is initially added. This material is then placed in syringes for injection, curing through an endothermic reaction in approximately ten minutes to form a nanocrystalline CaP structure [12].


Figure 1 Intra-op demonstration of the AccuFill® and BMAC mixture. Normal color is white when hydrated with NSS.

This technique has been reported on by the senior author, with application to foot and ankle,  as well as others for use in the knee [2,11,13].

With the new proposed technique, BMA is harvested from the surgeons’ location of choice (distal tibia, proximal tibia, calcaneus, iliac crest). The senior author typically uses the distal tibia unless contraindicated. The BMA is harvested using the Biomet BioCUETM (Zimmer-Biomet, Inc, Warsaw, IN) system. This process includes mixing 5-cc of the anticoagulant citrate dextrose solution formula-A (ACD-A) with each 25-cc of bone marrow aspirated. A trochar is tamped into the location of harvest, 30 cc syringe attached to the luer-lock, and constant back-pressure is applied to the syringe until 25-cc’s of blood is aspirated (30-cc fluid total). The solution is spun down per protocol into a BMAC product.

When ready, the BMAC is placed back onto the surgical table. The AccuFill® kit is opened and slowly the BMAC is mixed with the CaP powder (Figure 1).


Figure 2 Mixing AccuFill® with NSS and BMAC results in small crystal precipitate formation which can clog the injection syringe.

Reconstitution should be performed slowly with gradual addition of the liquid BMAC until the desired consistency is achieved. This amount will be more variable from case to case compared to the normal process which we typically find uses 3.2-cc of NSS. Differences in BMA/BMAC from patient to patient (cell concentration and density) as well as the overall increased viscosity of BMAC over NSS typically results in more marrow liquid volume than NSS to be utilized. We have seen ranges from 3.5 – 4.2cc of BMAC per standard 5cc of CaP. Once the desired consistency is achieved, the material is then prepared and injected into the BML per normal protocol. The surgeon should appreciate the blushing effect as the material interdigitates within the cancellous bone and BML. Side table analysis shows a similar 10 minute hardening time once components are combined to give an estimate of handling and waiting time before cannulated drills are removed from the bone.

Some keys to the technique include:

  1. Do not mix NSS and BMAC into the CaP. This results in formation of small precipitated crystals that will clog the syringe during injection. (Figure 2) Use either NSS or BMAC.
  2. One filled syringe of BMAC/CaP could be saved and placed in a basin of warm NSS to mimic the curing process (addition of heat) to approximate the time to hardening for determining cannulated drill removal.

Case Report

A 26-year-old female presented to the office with complaint of left ankle pain. She had been in a motor vehicle accident two years prior but had not sustained any fractures on her emergency department evaluation despite pain and bruising to the ankle. She underwent a period of protected weight-bearing, physical therapy, and discharge to resume normal activities. Due to continued discomfort, she underwent left ankle arthroscopy and lateral ankle ligament stabilization one year later. Still with continued daily pain on weight-bearing to the ankle one year after the surgical intervention, she ended up seeing the senior author (J.R.M.) for evaluation.

Physical exam noted pain on palpation of the medial and lateral malleoli, the anterior joint line, and deep palpation to the ankle gutters. There was also a decrease in ankle dorsiflexion. Suspecting a possible osteochondral lesion or BML, an MRI was ordered. The results demonstrated a low T1 / high T2 signal in the lateral and central-medial aspect of the talar dome, indicative of a BML. (Figure 3) Conservative and surgical options were presented to the patient and she opted for SCP® of the talar dome with BMAC.

On the day of surgery, the above described surgical technique was implemented. In this instance, the 5-cc of CaP powder was rehydrated with 4-cc of BMAC to achieve the desired consistency. Using fluoroscopic C-arm guidance, the BML was targeted and 5-cc of BMAC/CaP was used. The cannulated drills were left in place for 10 minutes and then removed. The joint was evaluated arthroscopically and no extravasation of the material was seen intra-articularly.


Figure 3 MRI T2 coronal (top) and sagittal (bottom) images of the left ankle. Images demonstrate the BML to the lateral (left, top-bottom) and central-medial (right, top-bottom) talus.

Arthroscopy portal incision were closed with nylon, a soft dressing was applied, and the patient was placed in a CAM boot to be weightbearing as tolerated in the boot until follow-up in two weeks.

At her first follow-up two weeks after the surgery, the patient stated only mild pain and the need to take opioid medication for relief over the first two days post-operation. Sutures were removed, and the patient was to continue CAM weight bearing with implementation of physical therapy in two weeks with transition into a sneaker as tolerated. At 6 weeks post-operation, the patient stated feeling greater than 90% improved from the pre-operative setting with VAS scale decrease from a consistent 9/10 pain to occasional 1-2/10 discomfort to the surgical ankle. She has remained at this level through continued follow-up.


Osteoarthritis (OA)  is a multifactorial disease process that involves all of the structures around the joint: articular cartilage, subchondral bone plate, bone marrow, synovial fluid, and the surrounding soft tissue structures [14]. Through the work of Radin the relationship between bone and cartilage was established, revealing damage to the subchondral bone correlated to knee OA pain and joint destruction [15]. BMLs are a result of subchondral damage, often a response to continued stress, similar to that of a stress fracture and are sometimes referred to as insufficiency fractures or non-healing (non-union) fractures [2]. The bone responds through stimulating a repair process, creating a focal area of sclerotic bone – the core of the developing BML. On MRI these areas are visualized as decreased signal uptake on T1 (sclerotic core of the BML) and increased signal uptake on T2 weighted-images (blood, synovial fluid, or water content) [2]. Continued weightbearing results in forces being transmitted through this core to the weaker cancellous periphery, resulting in further breakdown, creating the insufficiency fracture. This bone histologically shows decreased mineralization, increased vascularity, and a fibrotic quality [14]. Furthermore, this now soft focal area does not transmit joint loads normally, leading to a process that causes cartilage attrition [2]. This imbalance and cyclic process of damage over repair, lesion evolution, cartilage damage, and bone or joint pain has been well described by Sharkey et al (2012) [2]. Ultimately, the patient has to make a decision between palliative care or joint replacement. However, the SCP® technique has been introduced as a minimally invasive procedure that solves the problem of BML-related pain while preserving joint motion.

The SCP® procedure with our BMA addition offers another conservative surgical approach for the treatment of BML not just in the ankle as demonstrated here, but other appropriate joints or regions of BMLs seen on MRI. Historically the senior author diagnoses this condition based on patient subjectively complaining of chronic deep ankle pain, specifically with pain they either wake up with or have whether weightbearing or not. The subsequent ordered MRI oft correlates with marrow edema to that area of discomfort.  Often the lesions persist many months after the inciting event and represent an insufficiency fracture of the cancellous bone. This has been seen on serial MRI studies greater than three months apart at our practice. This procedure is often offered as a “no-bridges burned” solution to put off more complex surgery such as ligament reconstructions, ankle fusions, or ankle replacements. Knee results for treatment of advanced arthritis with concomitant BMLs have demonstrated that the SCP® procedure reduced VAS pain scores by greater than 4 points and delayed the need for total knee arthroplasty (TKA) in 70% of patients by at least two years [13]. We look to achieve the same results in the ankle when we offer the procedure to appropriate patients.

Synthetic forms of CaP have been created to repair and augment natural cancellous bone pathology. AccuFill®, the product used in this technique, is a proprietary nanocrystalline CaP powder formulation, when mixed with NSS creates a flowable putty that can be injected into lesions percutaneously. Once it hardens, activated endothermically by body temperature (37°C), it is slowly converted to and replaced by normal bone over subsequent months. Its structure has a 65% total porosity and 1-300µm pore size, allowing for a high surface area to facilitate bony in growth.  The 10MPa of compressive strength, achieved after 10 minutes of set time, is comparable to normal cancellous bony and permits immediate weightbearing post-operation.

In trying to achieve greater osteo-biology, we postulated that the addition of BMAC to the AccuFill® would give us the properties of osteoconduction, osteogenesis, and inductive growth factors. With the scaffold present, BMACs ability to add MSCs, OPG cells, HSCs, and platelets (degranulating growth factors VEGF & TGF-β) to this technique would in theory make sense to achieve a more superior local environment to healing [3,4,6,7]. While osteoinductive qualities to BMAC may be debated due to the lack of bone morphogenic protein (BMP), the protein most closely and traditionally linked to osteoinduction, growth factors like VEGF and TGF-β have been linked to inductive activity and play a role in regulating osteogenesis [6,16,17]. Further, TGF- β superfamily proteins have been shown to aid in articular (hyaline) cartilage restoration [17].

Similar theories have been attempted in combining osteobiologic materials. Mixing CaS with PRP has been shown to demonstrate bone regeneration qualities in humans [10]. Torres et al (2015) reported on a BMAC/HA combination in vitro [18]. Desired results of the combination versus controls included: (1) scanning electron microscopy visualization of marrow cells adherent to the scaffold surface in a scattered pattern days after preparation; (2) higher mean cell viability/proliferation as time increased; (4) greater cell growth rate; and (5) greater osteoblastic gene expression (ex. Col 1, ALP, BMP-2).  Combinations of PRP, BMAC, and CaP granules (CPG) have also been studied in animal models [8]. Kadiyala et al (1997) demonstrated abundant bone tissue formation after 8 weeks in rats treated with a MSC/HA-triCaP graft [19]. To the authors’ knowledge, no one has reported on the combination of BMA concentrate as the material to re-constitute a nanocrystalline CaP-type product.

The goal of our report is to describe an additional technique for an established procedure that may increase patient results and decreased surgical complications. As osteobiology is combined through synthetic (CaP, CaS, HA) and minimally invasive extraction technique (aspirating bone marrow, venipuncture for PRP harvest), the surgeon can create materials comparable to autogenous bone graft with a wide array of clinical applications [8,9]. The procedure can be adapted for the management of delayed or non-unions, tumors, cysts, or revision joint replacement. It can be implemented when greater osteobiology is demanded (autogenous bone graft, iliac crest source) but donor site morbidity is not desired. It can also be utilized in instance where the host is impaired (diabetes, chronic steroid, osteoporosis, post-menopausal, elderly, tobacco use) and the necessity of bone growth supplementing techniques is desired. We have used this technique in treating BMLs to the tibial (malleoli), talus, calcaneus, cuboid, cuneiforms, 2nd metatarsal base, and 1st metatarsal head with good results.

We realize this technique is not an exact science and poses many questions. Differences in BMA cell concentration and density from patient to patient would lead to differences in product characteristics.  This consists of varied preparation and handling standards (time to cure; volume of BMAC to hydrate), altered curing rates in-vivo, and potentially change either scaffold structure or physiological properties (pore size, compressibility) of the AccuFill®. Another point of debate is the osteoinductivity and addition of growth factors by BMA/BMAC [3-5,16,17,19]. It has been studied with limited publications or clarity. This process requires much more testing for it to become an exact science and understand what is exactly happening biochemically. However, the mixing of biologics is common in medical use and this technique should not be avoided because of the unknown. We ultimately feel that this technique provides an alternate or adjuvant to the currently available treatments for bone regeneration therapy.

Authors Note

The senior author has been performing foot and ankle SCP® for the past 2 years. In the time from the first time this technique was attempted until publication, he has seen no difference in patient complications or adverse events. Additionally, as stated above, where as the normal technique used 3.2cc of NSS to create a reproducible consistency in the putty, he has used variable amounts of BMAC to achieve the same consistency.


  1. Felson DT, Chaisson CE, Hill CL, et al. The association of bone marrow lesions with pain in knee osteoarthritis. Ann Intern Med. 2001;134(7):541-549.
  2. Sharkey PF, Cohen SB, Leinberry CF, Parvizi J. Subchondral bone marrow lesions associated with knee osteoarthritis. Am J Orthop. 2012;41(9):413-417.
  3. Sampson S, Botto-van Bemden A, Aufiero D. Autologous bone marrow concentrate: review and application of a novel intra-articular orthobiologic for cartilage disease. Physician Sport Med. 2013;41(3):7-18. doi:10.1007/s13398-014-0173-7.2.
  4. Ishihara A, Helbig HJ, Sanchez-Hodge RB, Wellman ML, Landrigan MD, Bertone AL. Performance of a gravitational marrow separator, multidirectional bone marrow aspiration needle, and repeated bone marrow collections on the production of concentrated bone marrow and separation of mesenchymal stem cells in horses. Am J Vet Res. 2013;74(6):854-863.
  5. Yamada T, Yoshii T, Sotome S, et al. Hybrid grafting using bone marrow aspirate combined with porous β-tricalcium phosphate and trephine bone for lumbar posterolateral spinal fusion. Spine (Phila Pa 1976). 2012;37(3):E174-E179. doi:10.1097/BRS.0b013e3182269d64.
  6. Khan WS, Rayan F, Dhinsa BS, Marsh D. An osteoconductive, osteoinductive, and osteogenic tissue-engineered product for trauma and orthopaedic surgery: how far are we? Stem Cells Int. 2012:1-7. doi:10.1155/2012/236231.
  7. Block JE. The role and effectiveness of bone marrow in osseous regeneration. Med Hypotheses. 2005;65(4):740-747. doi:10.1016/j.mehy.2005.04.026.
  8. Hakimi M, Grassmann J-P, Betsch M, et al. The composite of bone marrow concentrate and prp as an alternative to autologous bone grafting. PLoS One. 2014;9(6):1-18. doi:10.1371/journal.pone.0100143.
  9. Hukic S. Bone marrow aspirate vs. bone morphogenetic protein (RHBMP-2) in multilevel adult spinal deformity surgery and the feasibility of using adult mesenchymal stem cells. Univ North Texas Heal Sci Cent. 2009;(2009). http://search.proquest.com/docview/305156190?accountid=8359.
  10. Intini G, Andreana S, Intini FE, Buhite RJ, Bobek LA. Calcium sulfate and platelet-rich plasma make a novel osteoinductive biomaterial for bone regeneration. J Transl Med. 2007;5(13):1-13. doi:10.1186/1479-5876-5-13.
  11. Miller JR, Dunn KW. Subchondroplasty of the ankle: a novel technique. Foot Ankle Online J. 2015;8(1):1-7. doi:10.1017/CBO9781107415324.004.
  12. Park S-H, Tofighi A, Wang X, et al. Calcium phosphate combination biomaterials as human mesenchymal stem cell delivery vehicles for bone repair. J Biomed Mater Res. 2011;97(2):235-244. doi:10.1002/jbm.b.31805.
  13. Cohen SB. 2-year outcomes of the treatment of defects from bone marrow lesions with subchondroplasty.
  14. Farr J, Cohen SB. Expanding applications of the subchondroplasty procedure for the treatment of bone marrow lesions observed on magnetic resonance imaging. Oper Tech Sports Med. 2013;21(2):138-143. doi:10.1053/j.otsm.2013.03.006.
  15. Radin EL, Rose RM. Role of subchondral bone in the initiation and progression of cartilage damage. Clin Orthop Relat Res. 1986;(213):34-40.
  16. Rahman MS, Akhtar N, Jamil HM, Banik RS, Asaduzzaman SM. TGF-β/BMP signaling and other molecular events: regulation of osteoblastogenesis and bone formation. Bone Res. 2015;3:1-16. doi:10.1038/boneres.2015.5.
  17. Oka K, Oka S, Sasaki T. The role of tgf-β signaling in regulating chondrogenesis and osteogenesis during mandibular development. Dev Biol. 2007;303(1):391-404. doi:10.1017/CBO9781107415324.004.
  18. Torres J, Lopes A, Lopes M a., et al. The benefit of a human bone marrow stem cells concentrate in addition to an inorganic scaffold for bone regeneration: an in vitro study. Biomed Res Int. 2015;2015:1-10. doi:10.1155/2015/240698.
  19. Tshamala M, Bree H Van, Animals D. Osteoinductive properties of the bone marrow mth or reality. Vet Comp Orthop Traumatol. 2006;19(3):133-141.