by Mathew M. John, DPM1, F. Buck Willis, PhD2
The Foot and Ankle Online Journal 3 (1): 1
Key words: Contracture reduction, Dynasplint, home therapy, rehabilitation.
Accepted: December, 2009
Published: January, 2010
Hallux Abductovalgus (HAV) is a bunion deformity causing abnormal angulation of the great toe towards the second toe. The incidence rate of HAV is 1% of all Americans[1-4] and this includes 9% of women over the age of 60 years old. This pathology causes pain, inflammation, and reduced or impaired functioning of the hallux in ambulation.
The current standard of care in treating this condition includes nonsurgical treatment such as shoe modification followed by surgical management. [5-8] Complications of surgical treatment are not without risk though. Osteotomies of the first metatarsal such as the Lapidus and distal chevron procedure have caused significant incidence of hallux varus.
Hallux varus refers to excessive medial deviation of the great toe. In addition to the frequent iatrogenic postoperative variety, hallux varus occurs as a pediatric/congenital pathology and as a rheumatic or posttraumatic condition. [9,10] This connective tissue pathology is also currently only treated with surgical procedures. [3-6,11]
Similar pathologies have symptomatic contracture which is defined as the molecular shortening of the connective tissue and these pathologies occur from postoperative or posttraumatic arthrofibrosis [12-14], immobilization [15,16], or occur secondarily to excessive neuromuscular tone. [16,17] A study by Usuba, et. al., examined nonsurgical, therapeutic treatments for contracture that was caused by surgical immobilization in rats.  After 40 days of surgical immobilization the mean rat knee flexion contracture was -125° (n = 60). Usuba, et. al., then tested the interaction of four protocols: Stretching with high vs. low torque and stretching of prolonged duration vs. short duration. The only statistically significant difference seen between treatment protocols was found with combined protocols of low-torque stretching for prolonged durations.
This combination of low-torque stretching for prolonged durations is exactly what was used in the Dynasplint systems. A study by John, et. al., examined efficacy of the Dynasplint modality for reduction of contracture causing Hallux Limitus (HL).  In this study, 50 patients were enrolled after diagnosis of HL which occurred following a bunionectomy or cheilectomy.
The duration of this randomized study was eight weeks, and experimental patients received low-torque, prolonged stretching in the metatarsal joint Dynasplint (MTD) for 60 minutes, three times per day.
The dependent variable in Dr. John’s study was change in Active Range of Motion (AROM) and there was a significant change for the experimental patients following use of this home therapy modality (P < 0.001, T = 4.224). Experimental patients in this study regained a mean 32° change in AROM, extension compared to only a mean 10° change in AROM for control patients. Dr John’s randomized, controlled trial showed conclusive efficacy of the MTD modality.14 A retrospective study (N = 61) by Kalish and Willis showed comparable results in patients’ regaining 73% dorsiflexion at the metatarsal joint after 4 weeks.  The purpose of this pilot study was to report the benefits that Dynamic Splinting (DS) had on reducing contracture in hallux varus and hallux valgus.
Ten patients’ were treated with Dynamic Splinting (DS) in this report, (six with HAV and four with hallux varus). The modality can be seen in Figure 1AB and this unit delivers force and counter force to achieve elongation of connective tissue for contracture reduction. The same unit may be used for both lateral and medial stretching and this alteration is analogous to the Metatarsal Dynasplint that stretches both in plantarflexion and dorsiflexion. [13,14]
Figure 1A and 1B Hallux valgus (A) and hallux varus (B) Dynasplint.
The initial fitting for patients included customization of the unit (patient’s foot length, girth, and varying degrees of hallux edema), and training on donning and doffing of the devices. Patients also received instruction on safety, general wear and care, and standardized tension setting goals. Dynamic splinting employs the protocol of low-load stretching for contracture reduction through an appropriate biomechanical device which increases the joint’s time at end range (of motion). [12-14,16,17]
Each patient was instructed to wear the DS initially for 10 minutes, three times a day (tid) while seated, with an initial tension setting of #1 (0.10 foot pound of torque). Patients were instructed to sequentially increase the wearing time until they were comfortable wearing the unit for 60 minutes, tid. This lowest intensity was used for becoming accustomed to the system, and the patients were instructed to increase tension on increment every two weeks after they were comfortable wearing the unit for 60 minutes, tid.
The outcome measurements in this study included changes in maximal AROM for all patients and changes in hallux alignment measured in resting, weight bearing position. The patients treated for HAV regained a mean 10° AROM (one month) and the patients treated for hallux varus regained a mean 9° AROM in 3 months. Measurement of hallux alignment was taken while resting (weight bearing). This variable yielded comparable gains of Hallux abduction 10° (HAV) and 9° for adduction (hallux varus).
The purpose of this study was to report the benefits that dynamic splinting had on reducing contracture in hallux varus and hallux valgus. This examination of the new modality for contracture reduction was beneficial in restoring AROM and achieving a more optimal hallux alignment. The DS employed a proven protocol in using low-torque, prolonged stretching to reduce contracture without surgery. [13-17] While surgical resolution of hallux varus and HAV are the current standard of care, therapeutic endeavors have been prescribed effectively for treatment of post operative rehabilitation , and the DS used in this study answered the call for therapeutic treatment for hallux contracture pathologies. [3,6,12-14,18]
The use of dynamic splinting in this pilot study caused no adverse events, and a future randomized, controlled trial would determine if this new modality is effective in separate populations of patients with hallux abducto valgus and hallux varus.
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Address correspondence to: University of Phoenix: Axia College, Adjunct Professor Health Sciences and Dynasplint Systems, Clinical Research Director.
1 Ankle & Foot Centers 2790 Sandy Point Rd. #300 Marietta GA, 30066. (770) 977-3668.
2 University of Phoenix: Axia College, Adjunct Professor Health Sciences, Dynasplint Systems, Clinical Research Director , PO Box 1735 San Marcos TX 78667 (512) 297-1833
© The Foot and Ankle Online Journal, 2010