Early mobilization after uncomplicated medial subtalar dislocation provides successful functional results

SLR - September 2011 - Irene Labib

Reference: Lasanianos NG, Lyras DN, Mouzopoulos G, Tsutseos N, Garnavos C. (2011). Early mobilization after uncomplicated medial subtalar dislocation provides successful functional results. J Orthopaed Traumatology. 12:37-43

Scientific Literature Review

Reviewed by: Irene Labib, DPM
Residency Program: University Hospital - University of Medicine and Dentistry of New Jersey, Newark, NJ

Podiatric Relevance:
Subtalar dislocation is a rare type of injury encountered in the lower extremity.  Medial subtalar joint dislocation is the most common and accounts for 85% of subtalar joint dislocations.  This prospective study focuses on isolated medial subtalar dislocations.  The prognosis for these injuries relies on three parameters: (1) immediate reduction (2) amount of energy absorbed by the soft tissues at the moment of impact, and (3) the period of post-reduction immobilization.  The vast majority of literature specify the period of immobilization to be between 4 and 8 weeks, with subtalar joint range of motion decreased by 30-50%.  This study proposes a 2-3 week period of immobilization in a cast, followed by early mobilization and range of motion exercises in order to provide better functional results. 

Methods:
Eight patients met the inclusion criteria of medial subtalar dislocation with open or closed injuries.  Patients were excluded if they had peritalar fractures, subtalar dislocation of another type, or comorbidities that would influence the rehabilitation protocol.  Mechanisms of injury ranged from motor vehicle accidents, fall from height and trapped foot.  Treatment was provided by immediate closed reduction in the emergency department under sedation.  A below the knee back slab splint was initially applied to the extremity.  A cast was applied 3-4 days later for a total of 3 weeks.  Active ankle and foot ROM and strengthening exercises as well as partial weight bearing were initiated at three weeks.  Patients progressed to full weight bearing by the fifth week after reduction.  Clinical results were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) Ankle Hindfoot scale.  A relative ankle range of motion score was created to assess remaining stiffness compared to the contralateral side.  Follow up assessment was conducted by clinical and radiographic examination every two months for the first six months and then yearly for a period of thirty-six months. 

Results:
After successful closed reduction was achieved, the hind foot was found to be well aligned and without neurovascular damage.  The mean percentage of ankle range of motion compared to the contralateral limb was 92.5% (range 82-97).  The mean AOFAS score was 90.75 points.  Two of the eight patients complained of transient mild pain that did not restrict them from their daily activities.  No radiographic evidence of arthritis or avascular necrosis of the talus was evident.  All patients returned to their previous occupation and were satisfied with the results.

Conclusions:
This study provided evidence that immediate reduction and early mobilization can be beneficial for an uncomplicated recovery following medial subtalar joint dislocation. The authors reassessed the optimal duration of the immobilization period and their results display that early ankle range of motion exercises and partial weight bearing provide better functional results than those achieved by longer periods of immobilization.  Early activity may help ligaments and tendons heal without compromising proprioception of the joint.  The study results were consistent, however due to the nature of the injury, a small sample size was the limitation of the study.