Tag Archives: arthroscopy

Spontaneous double tendon rupture of the ankle

by Jay Kaufman DPM1, Alexander Newton DPM2*, Payel Ghosh DPM3, Zachary Ritter DPM4

The Foot and Ankle Online Journal 10 (4): 3

We present an independent case study of a 54-year-old woman that underwent arthroscopic ankle synovectomy with an open Broström lateral ankle stabilization who eventually suffered a spontaneous tendon rupture of both the extensor digitorum longus (EDL) and extensor hallucis longus (EHL) during the post-operative period. Though the postoperative course was initially uneventful, the patient began experiencing pain and swelling about the ankle joint upon transition to full weight bearing three weeks following surgery, but prior to physical therapy implementation. She was subsequently diagnosed with a combined EHL and EDL tendon rupture as well as chronic tendinosis of both tendons. We present this case as a rare complication following arthroscopy directly related to chronic tendinosis, resulting in potentially detrimental implications during postoperative recovery period.

Keywords: spontaneous, extensor tendon rupture, arthroscopy

ISSN 1941-6806
doi: 10.3827/faoj.2017.1004.0003

1 – Physician; OAA Orthopedic Specialists, Allentown, PA
2 – Resident Physician; Department of Podiatric Surgery, St. Luke’s University Hospital, Allentown, PA
3 – Physician; Syracuse Podiatry, East Syracuse, NY
4 – Physician; Department of Foot and Ankle Surgery, Wound Care, and Podiatry. UPMC Susquehanna Hospital, Williamsport, PA
* – Corresponding author: anewton434@gmail.com

The incidence of tendon rupture following arthroscopic ankle intervention is rare. Spontaneous tendon rupture, with or without intervention, is uncommon. Generally, spontaneous tendon rupture is directly correlated with a combination of mild trauma and chronic degeneration of a tendon. Other contributing factors are systemic diseases, biomechanical abnormalities, fluoroquinolone use, and steroid usage. The Achilles tendon is the most common tendon to experience spontaneous rupture, followed by the patellar tendon, and the Tibialis Anterior (TA).

Specifically, a pes planovalgus foot type can cause excessive recruitment of the muscles required for ankle joint dorsiflexion, the long extensor tendons and the TA. Concomitant factors such as ankle equinus and obesity should be considered during the preoperative examination.

If tendon pathology is expected, a Magnetic Resonance Imaging (MRI) should be obtained. An increase in T2 signal intensity surrounding the tendon is consistent with tenosynovitis. Tendinosis, on the other hand would be delineated by tendon thickening on both T1 and T2 weighted images with increased T2 signal [1]. If the MRI is contraindicated, an ultrasound is a viable option.

Case Presentation

We report the case of a 54-year-old female, who sought a second opinion for continued lateral ankle pain and instability. She had an ankle MRI performed about one year prior to presentation and continued to have nearly daily recurrent left ankle sprains as well as constant aching left ankle pain. Pertinent findings on physical exam were a mild hindfoot varus deformity, a BMI of 40.4, intact manual muscle testing, lateral ankle instability, and tenderness on palpation of the lateral ankle including the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the sinus tarsi. After failing prior conservative treatment, surgical intervention was pursued via ankle arthroscopy and lateral ankle stabilization. Ankle arthroscopy was performed uneventfully through a standard anteromedial and anterolateral ankle portal. Postoperatively, she was placed in a posterior splint with the hindfoot placed in slight valgus position.

The postoperative course passed uneventfully until the patient was transitioned from a posterior splint to an ankle brace weight bearing as tolerated one month postoperatively. She was instructed to use assistive devices as necessary and given a prescription for rehabilitative therapy. A few days following weight bearing, the patient noted sudden increased swelling surrounding the ankle joint, along with stiffness and burning within her first three digits. Radiographs and labs to rule out fracture, infectious or inflammatory process were negative. With clinical improvement, she proceeded to complete several weeks of physical therapy with resolution of ankle instability; however, in addition to stiffness and weakness of her lesser toes she began to complain of great toe weakness.

An MRI of the left ankle and left foot was obtained approximately 3.5 months postoperatively. Imaging at the level of the ankle demonstrated a ruptured EDL and EHL retracting proximally above the tibiotalar joint without violation of the anterior joint capsule. MRI at the level of the foot demonstrated tendinosis of the same tendons distal to the level of the ruptures.


In 2012, Zengerink et al reviewed complications in ankle arthroscopy. He found neurologic injury to be the most common finding, followed by infection in a review of 1176 patients. Zengerink et al reported no tendon rupture following arthroscopic surgery within their follow up of approximately 7.5 years [2]. To our knowledge, there are only a small collection of prior reported incidences of tendon rupture following arthroscopy of the ankle joint. In 2010 Tuncer et al reported an incident of extensor hallucis longus and extensor digitorum longus insufficiency following radiofrequency ablation during ankle arthroscopy. Of note, intraoperatively both tendons were noted to be intact while the anterior capsule had been affected. However 10 weeks postoperatively, the patient did feel a “pop” and dual tendon rupture was then diagnosed [3].

Single tendon rupture following ankle arthroscopy is a rarity. Rupture of two tendons simultaneously without consideration of iatrogenic injury is improbable. The initial MRI, performed in 2010 prior to any surgical intervention, demonstrated an intact EHL, EDL, and TA. To further solidify our findings of this rare complication, a musculoskeletal radiologist was consulted (Figure 1). On MRI following any surgery, micrometallic debris can be detected in the soft tissues. This causes a susceptibility artifact in the tissues, which appears as multiple small foci of decreased signal on MRI. Figure 2 shows the metallic artifact surrounding the region of repair in the lateral ankle. No artifact is present in the anterior tissues surrounding the ruptured extensor tendons. Lack of metallic artifact as well as no anterior surgical track strongly argues against any kind of surgically induced laceration of the tendons.

Figure 1 MRI of normal ankle anatomy.

Figure 2 Micrometallic debris at site of lateral ankle repair.

Figure 3 demonstrates thickening and increased signal intensity of the long extensor tendons distal to the level of the rupture, consistent with tendinosis. If the tendons had been lacerated during surgery, the cut edges of the tendons would be expected to be sharply demarcated without thickening or increase in signal intensity.

Figure 3 MRI demonstrating absent extensor tendons at rupture site.

Figure 4 MRI demonstrating tendonitis distal to rupture.

Figure 4 demonstrates the lack of the long extensor tendons near the level of the ankle joint. The TA has remained intact. Figures 5 and 6 demonstrate the intact articular surface of the lateral aspect of the joint showing no issues with ingress or egress flow allowing us to further conclude that the articular capsule remains intact.

Figure 5 Intact intra-articular surface of the lateral shoulder of talus and fibula.

Figure 6 Distal tip of fibula and lateral talus.

If iatrogenic causes are ruled out, predisposing factors for tendon rupture must be considered. When an MRI is ordered for evaluation, chronic conditions can be missed as a result of being focused on acute pathologies. In general, chronic tendinosis and extensor tendon pathology are underreported in MRI reports [1]. This patient had multiple predisposing factors for increased strain on her extensor tendons: morbid obesity with a BMI of 40.4, pes planovalgus foot type, equinus strain following immobilization from surgery, and recurrent ankle sprains all likely contributed to rupture in the postoperative period. Additionally, patients bear weight differently on weight-bearing joints following surgery.

In the postoperative period, altered stress across the ankle joint in combination with a period of immobilization likely led to spontaneous rupture, due to the underlying tendinosis now appreciated on the postoperative MRI. In addition to noted EHL and EDL tendinosis, there was noted metallic artifact lateral about the Broström site as would be expected, however, there was no metallic artifact within the anterior soft tissues surrounding the extensor tendons, nor a surgical tract from the ankle joint to the anterior ankle tendons.


Spontaneous lower extremity tendon rupture, while rare, is a real possibility. We do not believe that the rupture of the long extensor tendons was due to iatrogenic injury. Rather, we believe that the combination of chronic tendinosis, immobility following surgery, and changing stresses on an already unhealthy tendon lead to tendon rupture as the patient’s physical therapy regimen was escalated. We believe that prevention of this hinges on proper diagnosis of chronic tendon pathology pre-operatively. When a patient presents preoperatively with gait dysfunction, a thorough evaluation of tendon pathology should not be overlooked prior to any surgical planning.


  1. Tsao LY. “Ankle Extensor Tendon Pathology.” www.radsource.us/ankle-extensor-tendon-pathology-2. Radsource MRI Web Clinic. July 2014.
  2. Zegerink M, van Dijk CN. “Complications in Ankle Arthroscopy.” Knee Surgery Sports Traumatology Arthroscopy. 2012 Aug; 20 (8): 1420-31.
  3. Tuncer S, Aksu N, Isiklar U. Delayed rupture of the extensor hallucis longus and extensor digitorum communis tendons after breaching the anterior capsule with a radiofrequency probe during ankle arthroscopy: a case report. Journal of Foot and Ankle Surgery 2010; Sep-Oct; 49(5).

Evaluation of the Deltoid Complex in Supination External Rotation Ankle Fractures

by Travis Motley DPM, MS, FACFAS1  , J. Randolph Clements, DPM, FACFAS2 ,
Kelly Moxley, DPM3, Brian Carpenter, DPM, FACFAS4 , Alan Garrett, DPM, FACFAS5

The Foot and Ankle Online Journal 3 (4): 1

We present the results of a prospective study of supination external rotation ankle injuries with an isolated fibula fracture on plain radiographs. The purpose of this study was to see if a correlation exists between the preoperative evaluation and the intraoperative arthroscopic evaluation of the deltoid ligament complex in these injuries. Gravity stress radiographs of the ankle were evaluated to assess deltoid ligament competence. If the medial clear space was > 4 millimeters, injury to the deltoid ligament complex was assumed. We correlated stress radiograph measurements of the medial clear space with arthroscopic evaluation of the deltoid ligament at the time of open reduction internal fixation in 19 patients. Arthroscopic findings demonstrated that of the 19 patients that underwent open reduction internal fixation, 2 (10%) had intact deltoid ligaments, 2 (10%) had partial ruptures, and 15 (79%) had complete rupture of the deltoid ligament. After placement of fixation, the medial clear space on stress gravity films was measured again to confirm reduction.

Key words: Isolated fibula fracture, deltoid ligament, arthroscopy.

Accepted: March, 2010
Published: April, 2010

ISSN 1941-6806
doi: 10.3827/faoj.2010.0304.0001

The supination-external rotation (SER) injury described by Lauge-Hansen [1] is the most common type of ankle fracture. [2,3]

SER injuries begin anteriorly and progress in a clockwise fashion so that stage I injury includes the anterior inferior tibiofibular ligament. As rotation of the talus continues, stage II will involve either rupture of the lateral ankle ligaments or a fracture of the fibula at the level of the ankle joint. With continued progression, stage III involves either an injury to the posterior talofibular ligament or an avulsion injury of the posterior malleolus. Stage IV includes injury to either the deltoid ligament complex or a fracture of the medial malleolus. The surgeon can easily determine that the fracture is unstable when the medial malleolus is broken. However, determining fracture instability based on deltoid ligament competency is more challenging.

Some surgeons still rely on medial tenderness, swelling, or ecchymosis as indicators of deltoid ligament incompetency. The oversight here is that the deltoid ligament is a composite of two ligaments: deep and superficial. The superficial deltoid includes the anterior tibiotalar ligament and the tibionavicular ligament. The posterior tibiotalar and tibiocalcaneal ligament make up the deep deltoid component.

Pankovich and Shivaram [4,5] demonstrated differences and roles of the superficial and deep components. The superficial deltoid ligament can be completely or partially torn and still produce “medial tenderness, swelling and ecchymosis.” If soft tissue indicators alone are used, many stable (non-displaced SER II) fractures will be treated operatively.

Stage II SER injuries with an isolated non-displaced fibula fracture are generally treated non-operatively, but fracture patterns that progress to medial injury (SER IV) are generally treated with open reduction internal fixation (ORIF).

Clinically, distinguishing between an isolated fibula fracture (SER II) and an injury that includes a medial ligamentous injury (SER IV) can be difficult.

Previous authors have shown that medial tenderness, bruising, or ecchymosis are unreliable predictors of medial ligamentous injury. [6,7,8]

Some authors report stress radiographs have a better prognostic value when evaluating for ligamentous SER IV (bimalleolar equivalent) injuries. [9,10] Evaluation of the medial clear space (MCS) in these bimalleolar equivalent injuries on stress radiographs has shown that American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Functional Survey scores decline with an increase in MCS [11] when treated conservatively.

The purpose of this study was to see if a correlation exists between the preoperative evaluation and the intraoperative arthroscopic evaluation of the deltoid ligament complex in SER IV (bimalleolar equivalent) ankle fractures.

Materials and Methods

Patients included in this study were consulted to the podiatry service at our institution with an isolated closed distal non-displaced/minimally displaced fibula fracture with and a widened medial clear space (MCS) > 4-mm on gravity stress views. After informed consent was obtained, patients underwent ORIF with ankle arthroscopy. At the time of arthroscopy, the deltoid ligament was noted as intact, partial tear, or ruptured. Talar dome lesions evident during arthroscopy were also documented.

Radiographic measurements for each patient preoperatively included MCS on standard mortise and stress gravity views, preoperative superior clear space (SCS), preoperative contralateral stress gravity, and postoperative stress gravity views. The MCS was measured as the distance between the medial border of the talus and the lateral border of the medial malleolus on a line parallel and 5-mm below the talar dome. (Fig. 1) The SCS was the distance between the distal tibia and the highest point of the talar dome.

Figure 1  Technique for measurement of the medial clear space (MCS) on stress gravity view.


Nineteen patients met the specific inclusion criteria of an isolated distal non-displaced/minimally displaced fibula fracture and a MCS > 4-mm. From arthroscopic evaluation, fifteen patients (79%) were found to have a complete rupture of the deltoid ligament on arthroscopic evaluation, two (10.5%) were found to have a partial tear, and two (10.5%) were found to have an intact deltoid ligament. Generally, patients with higher MCS values were found to have complete rupture of the deltoid complex while those with lower MCS values were found to have intact or only partial deltoid tears. The average MCS in the patient group found to have a complete rupture of the deltoid ligament was 5.44- mm. (Table 1). Stress gravity views also demonstrated an increase in MCS from standard radiographic ankle views. Arthroscopic evaluation also identified talar dome lesions in 7 (37%) of our patients. Of these, 3 (16%) were medial, 3 (16%) were lateral, and 1 (5%) were centrally located within the talar dome. Due to the limited size of this data set, statistical analysis is not feasible to draw any meaningful conclusions.

Table 1  Medial clear space (MCS) measurements in patients with an intact deltoid ligament, partially torn deltoid ligament, and those with ruptured deltoid ligaments as demonstrated on arthroscopic evaluation. MCS = medial clear space on pre-operative mortise view, MCS SG = medial clear space on stress gravity view, MCS CL = medial clear space on contralateral mortise view, MCS PO = medial clear space post-operative views.


The SER mechanism is the most common pattern observed with ankle fractures. [2,3] Isolated non-displaced fibula fractures are routinely treated non-operatively. However, SER IV injuries involving the deltoid ligament complex represent unstable ankles and the consensus amongst foot and ankle surgeons is that SER IV ankle fractures should be treated surgically in order to restore anatomic alignment and stability to the ankle joint. Several publications have shown the advantages of proper treatment of these injuries. [12-15] The purpose of our study was to see if a correlation exists between the preoperative evaluation and the intraoperative arthroscopic evaluation of the deltoid ligament complex in SER IV (bimalleolar equivalent) ankle fractures.

Open reduction and internal fixation of SER IV injuries is widely considered standard. Some authors have advocated ORIF in those bimalleolar equivalent injuries where the MCS value is >4-mm.

Clements, et al., [11] has shown previously that patients with an MCS value of up to 5-mm do well (measured with AOFAS hindfoot and ankle functional satisfaction survey) without operative intervention. These authors suggest that MCS values less than 5- mm may represent those patients with only a partial tear of the deltoid ligament complex and subsequently a more stable ankle than those patients with complete deltoid ligament rupture.

Schuberth, et al., [8] concluded that a widened medial clear space was not an indicator of deltoid ligament rupture in their correlation between radiographic and arthroscopic evaluation in their patients. We found that 2 of our 19 patients had an intact deltoid ligament with arthroscopic evaluation and a gravity stress radiographic finding of MCS > 5-mm. We consider this more of an exception and suggest that any bimalleolar equivalent injury with an MCS > 5-mm be carefully evaluated and correlated to the contralateral ankle.

The traditional use of medial tenderness, swelling, and ecchymosis in conjunction with a lateral malleolar fracture is no longer reliable as a means of accurately determining medial side injury. These signs were thought to suggest deltoid ligament rupture; however, recent literature is replete with data that clinical symptoms of medial tenderness, swelling, and ecchymosis are not predictive of deltoid ligament disruption. [16,17] Because of the uncertainty in these physical findings, clinicians rely more on gravity stress or medial stress radiographs. These radiographs apply force by either gravity or manual rotation to the deltoid ligament complex. An anterior-posterior image is taken. If the medial clear space widens past 4mm, the presumption is that the deep deltoid ligament has failed and can no longer tether the talus to the medial malleolus. The authors of this study directly visualized the deep deltoid by arthroscopy to determine if there was a direct correlation between widening of the medial clear space and deep deltoid ligament incompetency.

Since, 9% of the patients in this study had intact deep deltoid ligaments by arthroscopy but showed widened medial clear space measurements radiographically, one must assume the deep deltoid ligament is attenuated during the injury. The question remains if this attenuation of the deep deltoid ligament creates significant tibiotalar instability. Ramsey and Hamilton18 suggested that a 1-mm displacement increases the contact forces of the tibiotalar joint by 42%.

Other techniques have been described to evaluate the deltoid ligament complex. Magnetic resonance imaging provides the best non invasive means of evaluating the deltoid ligament complex. However, the cost is prohibitive at this point. Ultrasound provides a less costly, non-invasive way to evaluate the deep deltoid. Chen, et al., [19] examined with sonography to evaluate the deltoid ligament. Patients who showed complete rupture of the deltoid ligament received operative treatment. During surgical repair of the fibula, a medial exploration was performed to confirm deep deltoid ligament disruption. A recent publication simply used weight-bearing radiographs to distinguish stable and unstable SER fractures. Patients with questionable injuries (SER II versus SER IV) had weight- bearing radiographs. In this experiment, the use of weight bearing radiographs was used to determine the need for operative treatment. If ankle joint congruity was appreciated on weight-bearing films, 90% of the patients were treated successfully with non-operative treatment. [20]

Current literature suggests that a compromised deltoid ligament complex can be demonstrated in non-displaced fibula fractures by many methods. Probably the most common modality is the gravity stress radiograph because it does not require special equipment and can be rapidly performed using standardized techniques. Medial clear space measurements > 4-mm on gravity stress films have been assumed to correlate to deltoid ligament incompetence. However, based on data obtained in this small study and a previous study published by our group [11], medial clear space values may need to be reassessed.

We propose that a medial clear space measurement < 5-mm in non-displaced fibula fractures may do well with conservative treatment as this likely represents only a partially torn deltoid ligament. A larger study group with arthroscopic evaluation of the deltoid ligament in patients with medical clear space measurements of 5-mm treated conservatively and those treated operatively with outcome measures would be beneficial.


Deltoid ligament competency can be established with a stress gravity view on presentation. We further evaluated the deltoid ligament complex with arthroscopy at the time of ORIF in these bimalleolar equivalent ankle injuries. We used arthroscopy to confirm widened medial clear space values indeed correlates to a disruption of the deep deltoid ligament. Furthermore, patients who only widened to 5mm on stress gravity images are more likely to have a partially torn deltoid ligament. These represent stable ankle fracture and should be considered for non- operative treatment. There is a high correlation between MCS on stress views and incompetent deltoid ligaments. The extent of subtle deltoid ligament injuries is difficult to determine. Advanced imaging modalities may prove to be superior to stress imaging. Our findings support other recent publications that the medial clear space measurement used to determine deep deltoid ligament incompetency could be increased to 5mm.

Conflicts of Interest

The authors report no conflict of interest.


1. Lauge-Hansen N. Fractures of the ankle II. Combined experimental-surgical and experimental-roentgenologic investigations. Arch Surg 1950 60: 957-985.
2. Jensen SL, Andresen BK, Menche S, Nielsen PT. Epidemiology of ankle fractures. A prospective population-based study of 212 cases in Aalborg, Denmark. Acta Orthop Scand 1998 69: 48-50.
3. Yde J. The Lauge Hansen classification of malleolar fractures. Acta Orthop Scand 1980 51: 181-92.
4. Pankovich AM, Shivaram MS. Anatomical basis of variability in injuries of the medial malleolus and the deltoid ligament. I. Anatomical studies. Acta Orthop Scand 1979 50: 217-223.
5. Pankovich AM, Shivaram MS. Anatomical basis of variability in injuries of the medial malleolus and the deltoid ligament. II. Clinical studies. Acta Orthop Scand 1979 50: 225-236.
6. McConnell T, Creevy W, Tornetta PIII. Stress examination of supination external rotation-type fibular fractures. JBJS 2004 86A (10): 2171-2178.
7. Egol KA, Amirtharajah M, Tejwani NC, Capla EL, Koval KJ. Ankle stress test for predicting the need for surgical fixation of isolated fibular fractures. JBJS 86A (11): 2393-2399.
8. Schuberth JM, Collman DR, Rush SM, Ford LA. Deltoid ligament integrity in lateral malleolar fractures: a comparative analysis of arthroscopic and radiographic assessments. J Foot Ankle Surg 2004 43(1): 20-29.
9. Park SS, Kubiak KA, Kummer F, Koval KJ. Stress radiographs after ankle fracture. J Orthop Trauma 2006 20(1): 11-18.
10. Gill B, Risko T, Raducan V, Grimes JS, Schutt Jr, RC. Comparison of manual and gravity stress radiographs for the evaluation of supination-external rotation fibular fractures. JBJS 2007 89A (5): 994-999.
11. Clements JR, Motley TA, Garrett A, Carpenter BB. Nonoperative treatment of bimalleolar equivalent ankle fractures: a retrospective review of 51 patients. J Foot Ankle Surg 2008 47(1): 40-45.
12. Michelson JD. Fractures about the ankle. JBJS 1995 77A (1):142-152.
13. Joy G, Patzakis MJ, Harvey JP Jr. Precise evaluation of the reduction of severe ankle fractures. JBJS 1974 56A (5): 979-993.
14. Mont MA, Sedlin ED, Weiner LS, Miller AR. Postoperative radiographs as predictors of clinical outcome in unstable ankle fractures. J Orthop Trauma 1992 6:352 -357.
15. Burns WC 2nd, Prakash K, Adelaar R, Beaudoin A, Krause W. Tibiotalar joint dynamics: indications for the syndesmotic screw—a cadaver study. Foot Ankle 1993 14:153-158.
16. Egol KA, Amirtharajah M, Tejwani NC, Capla EL, Koval KJ. Ankle stress test for predicting the need for surgical fixation of isolated fibular fractures. JBJS 2004 86A (11): 2393-2398. (Erratum in: JBJS 2005 87A: 857. Erratum in: JBJS 2005 87A:161).
17. McConnell T, Creevy W, Tornetta P 3rd. Stress examination of supination external rotation-type fibular fractures. JBJS 2004 86A (1): 2171-2178.
18. Ramsey PL, Hamilton W. Changes in tibiotalar area of contact caused by lateral talar shift. JBJS 1989 71A (3): 1548-1555.
19. Chen PY, Wang TG, Wang CL. Ultrasonographic examination of the deltoid ligament in bimalleolar equivalent fractures. Foot Ankle Int 2008 29(9): 883-886.
20. Weber M, Burmeister H, Flueckiger G, Krause FG. The use of weightbearing radiographs to assess the stability of supination-external rotation fractures of the ankle. Arch Orthop Trauma Surg Epub 2010 Jan 16.

Address correspondence to: Travis Motley, DPM, MS, FACFAS . John Peter Smith Hospital, 1500 South Main Street, Fort Worth, TX 76104.  tmotley@jpshealth.org

1  Assistant Professor, University of North Texas Health Science Center, Department of Orthopaedics, John Peter Smith Hospital, 1500 South Main Street, Fort Worth, TX 76104.
2  Carilion Clinic, Department of Orthopaedics, Three Riverside Place, Roanoke, VA 24014.
3  Juneau Foot & Ankle Center, 8800 Glacier Hwy #218, Juneau, AK 99801.
4  Associate Professor, University of North Texas Health Science Center, Department of Orthopaedics,
 John Peter Smith Hospital, 1500 South Main Street, Fort Worth, TX 76104.
Alan Garrett, DPM, FACFAS, Assistant Professor, University of North Texas Health Science Center, Department of Orthopaedics, John Peter Smith Hospital, 1500 South Main Street, Fort Worth, TX 76104.

© The Foot and Ankle Online Journal, 2010

Isolated Extensor Hallucis Longus Paralysis after Knee Arthroscopy: A case report

by Emmanuel P. Estrella, MD1 , Edgar Micheal T. Eufemio, MD2

The Foot & Ankle Journal 1 (10): 2

Arthroscopic surgery has gained widespread acceptance in the diagnosis and treatment of sports-related injuries to the knee. Neurovascular complications after knee arthroscopy are rare. The most common neural complications include injuries to the saphenous nerve and common peroneal nerve. Isolated paralysis of the extensor hallucis longus muscle has never been reported as a complication of arthroscopic knee surgery. However, it is not an uncommon complication in procedures around the proximal tibia or harvest of the fibula for bone grafting. We report a case of an isolated paralysis of the extensor hallucis longus muscle in a patient who had arthroscopic anterior cruciate ligament reconstruction and partial meniscectomy. A simple tendon transfer of the extensor hallucis longus to the extensor digitorum longus tendon allowed the hallux to dorsiflex and extend.

Key words: Nerve injury, arthroscopy, meniscectomy, tendon transfer, extensor hallucis palsy

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.  It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot & Ankle Journal (www.faoj.org)

Accepted: September, 2008
Published: October, 2008

ISSN 1941-6806
doi: 10.3827/faoj.2008.0110.0002

Arthroscopic knee surgery has been accepted as the standard treatment for anterior cruciate ligament (ACL) reconstruction and meniscus surgery. Although regarded as a minimally invasive surgery with low morbidity, complications still exist. [1] Neural complications of knee arthroscopy range from 0.6%-2.5% in reported series. [1,2,3] The nerve most commonly injured is the infrapatellar branch of the saphenous nerve on the medial aspect of the knee. This nerve can be injured with an incision during portal placement or harvest of the hamstring tendon for ACL reconstruction. [4,5,6]

Motor deficit from injury to the peroneal nerve after knee arthroscopy has been reported in a few case reports. [4,7,8,9.10]

Paralysis of the extensor hallucis longus (EHL) muscle has been frequently reported as a complication of procedures on the proximal part of the tibia, fibula or fibular graft harvest. [11,12] It can be an isolated injury or part of a peroneal nerve injury. In our literature search, we found no reported case of isolated EHL paralysis after knee arthroscopy. The purpose of this report is to present an unusual injury from a common arthroscopic knee procedure.

Case Report

A 14 year-old male sustained a twisting injury of the left knee while playing basketball. A consultation by an orthopedic surgeon was performed a few weeks after the incident because of persistent left knee pain. Physical examination of the left knee showed a positive anterior drawer’s and pivot shift test. A diagnosis of an ACL (anterior cruciate ligament) deficient knee was made and the patient was advised to undergo surgery. He had ACL reconstructive surgery using a hamstring graft and a partial lateral meniscectomy of the left knee. The patient noted loss of left big toe extension a day after the surgery. The lesser toe extensors and ankle dorsiflexion were intact. The patient was followed for several months and had no motor recovery.

The patient first consulted our clinic nine months after the arthroscopic ACL reconstruction and meniscectomy. He complained of the inability to extend the left big toe. Physical examination showed an MRC (Medical Research Council) muscle grade of 0/5 for big toe extension or dorsiflexion. The lesser toes and ankle were graded 5/5 on extension with no sensory deficit. There were no other motor and sensory abnormalities.

An electromyography-nerve conduction velocity (EMG-NCV) was done and showed complete denervation of the extensor hallucis longus muscle.

At one year after the ACL reconstruction, there was still no recovery of the dropped big toe and a surgical option was offered. Two years after the initial surgery, a decision to undergo surgery was made by the patient.

A tendon transfer was planned to restore the big toe extension. The tendons of the EHL and the EDL muscles were approached anteriorly, proximal to the extensor retinaculum. The EHL tendon was identified, transected and transferred to the common extensor digitorum longus tendons by a tendon weave suture technique under optimal tension with the ankle in plantigrade position. (Fig. 1)

Figure 1   Intraoperative view of the transferred distal tendon of the EHL (extensor hallucis longus) to the common tendons of the EDL (extensor digitorum longus) via tendon weave.

He was maintained in a cast boot for six weeks. He then started strengthening exercises for the transferred tendon-muscle unit with emphasis on simultaneous extension of all five toes. At the latest follow-up, at one year after the tendon transfer, simultaneous extension of the big and lesser toes was achieved with an MRC muscle grade of 4/5 for big toe extension. (Fig. 2)

Figure 2  Motor function at one year post-op.  Note the simultaneous extension of all five toes.


Isolated paralysis of the EHL muscle or as part of common peroneal nerve paralysis has been reported in procedures in the proximal part of the tibia such as high tibial or fibular osteotomies, tibial nailing or fibular graft harvest. [11,12,13] Most of these paralyses were transient and resolve within a few months.

In arthroscopic knee surgeries, perhaps one of the most serious nerve complications is peroneal nerve paralysis. Injury to the peroneal nerve may be due to entrapment or nerve capture during lateral meniscus repair [18,14], posterior trocar placement [4], posterior capsular penetration [9,10] or closed traction during intra-operative manipulation of the knee. [7] In cases of nerve entrapment by suture, release of the suture during re-exploration resulted in return of peroneal nerve function within six months. [8,14] In one study [4] , there was a neuroma in continuity on re-exploration that was resected and a nerve graft was performed. The authors suggested that the posterior placement of the trocar was the most probable cause of the neuroma formation. Other case reports showed peroneal nerve injury after arthroscopic meniscectomy alone. [9,10] The authors attributed the injury from posterolateral capsular instrument penetration during meniscectomy as evidenced by a scarred posterolateral knee capsule and an unusually high bifurcation above the knee of the common peroneal nerve on re-exploration. [10]

Deutsch, et al., [15] investigated the anatomic variability of the peroneal nerve bifurcation as a possible risk factor for nerve injury in knee arthroscopy. They studied the anatomy of the common peroneal nerve bifurcation and noted that in 10% of the 70 cadaveric knees studied; bifurcation was noted to be proximal to the knee joint with an average distance of 7.5 mm. Most bifurcation occurred at or below the fibular neck in 84.6% of cases. In the remaining 8.6%, bifurcation occurred distal to the knee joint but proximal to the fibular neck.

A literature search revealed no isolated injury of the nerve to the EHL muscle after knee arthroscopy. The case presented here therefore is an example of an unusual injury from a common procedure.

The nerve to the EHL muscle as studied by Elgafy, et al., [16] showed that the mean distance of the nerve from the deep peroneal nerve was 5.9 ± 1.7 cm distally from the most palpable point of the fibular head, with an average length of 5.0 ± 1.8 cm. However, they also reported that among the thirty-three branches of the EHL that was dissected in thirty legs, twenty-seven (90%) muscles had only one innervating branch.

A full explanation to the cause of the isolated paralysis of the EHL muscle could not be established. There were no surgical scars on the proximal lateral aspect of the leg that might be a cause of the injury to the nerve of the EHL. The injury might have occurred at the level of the knee joint where a capsular instrument penetration during meniscectomy was the cause, as reported by some authors [9,10] in addition to a possible high bifurcation of the common peroneal nerve. The peroneal nerve is posterior and deep to the biceps femoris at the level of the joint line, and the inferior lateral geniculate vessels lie along the posterolateral aspect of the capsule at the meniscal attachment. Injury to the peroneal nerve was at most partial, and it is possible that the fascicle destined to innervate the EHL muscle was the one that was injured.

Some authors emphasized that a thorough understanding of the anatomy and anatomic variability of the neurovascular structures about the knee is essential in order to avoid neurovascular complications during knee arthroscopy. [4,10,13] Flexion of the knee in 90º or the so-called “figure-of-four” position should be done when arthroscopic instruments approach the posterolateral corner of the knee to decrease the risk nerve injury in cases of capsular penetration since the neurovascular structures are more distant from the knee capsule in this position. [2,5,16]

Likewise, caution must be exercised when motorized instruments or arthroscopic forceps are used in the posterolateral aspect of the knee.

In summary, this case highlights that even in common procedures such as arthroscopic ACL reconstruction and meniscectomy, complications do occur. The most devastating complications are functional loss to the foot and ankle because of peroneal nerve injuries. General principles in knee arthroscopy should be observed in order to avoid such complications.


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Address correspondence to: Emmanuel P. Estrella, MD
Department of Orthopedics. Philippine General Hospital, Manila, Philippines 1000. Email: estee96@yahoo.com
Tel #: (632) 5242203

1Staff surgeon, University of the Philippines-College of Medicine,
Department of Orthopedics, Philippine General Hospital, Manila, Philippines, 1000.
2Resident, University of the Philippines-College of Medicine,
Department of Orthopedics, Philippine General Hospital, Manila, Philippines, 1000.

© The Foot & Ankle Journal, 2008