SLR - March 2021 - Amber M. Kavanagh

Changes in Tendon Elongation and Muscle Atrophy Over Time After Achilles Tendon Rupture Repair: A Prospective Cohort Study on the Effects of Early Functional Mobilization

Reference: Aufwerber S, Edman G, KG Silbernagel, Ackermann PW. Changes in Tendon Elongation and Muscle Atrophy Over Time After Achilles Tendon Rupture Repair: A Prospective Cohort Study on the Effects of Early Functional Mobilization. The American Journal of Sports Medicine. 2020;48(13):3296-3305.
 
Level of Evidence: Level II

Scientific Literature Review

Reviewed By: Amber M. Kavanagh, DPM 
Residency Program: Medstar Health Podiatric Surgery Residency – Washington DC
 
Podiatric Relevance: There are varying perceptions on the ideal postoperative rehabilitation course after Achilles tendon rupture repair. As podiatric surgeons increasingly treat these injuries, guidance is needed on the outcomes of tendon approximation paired with weight bearing restrictions and early range of motion. There has been a divide on whether early functional mobilization (EFM) after Achilles repair leads to better patient outcomes and tendon function. This article compares EFM to immobilization for patient-reported and functional outcomes including tendon elongation, cross sectional area (CSA), and Achilles Tendon Total Rupture Score (ATRS).

Methods: A total of 86 patients with a mean age of 39.3 years underwent Achilles rupture repair with a modified Kessler suture for tendon re-approximation. They were randomly divided into two groups with a 2:1 ratio for the EFM group and control/immobilization group. The EFM group was placed in a dynamic orthosis postoperatively and allowed to fully weight bear with increasing adjustments of allotted ankle range of motion after two weeks. The control group was kept non weight bearing for the first two weeks and transitioned to an ankle stable orthosis and full weight bearing after this time. Both groups continued unloaded ankle plantarflexion exercises and discontinued orthosis use at six weeks. The ATRS results were collected at six and 12 months postoperatively. Ultrasound imaging assessments for tendon elongation and CSA of the tendon and muscle belly were performed at two and six weeks and again at six and 12 months postoperatively and compared to the uninjured side.
 
Results: The mean ATRS at six months was higher in the EFM group compared to the control group: 65.8 vs 56.8 (P=0.045). At two weeks, the EFM group had greater tendon elongation than the control group: 1.88 centimeters vs 0.71 centimeters (P=0.005), however after time the control group continued to increase in tendon elongation while the EFM group decreased. Therefore, at six and 12 months there was no significant difference in tendon elongation between the groups: 1.73 centimeters for the EFM group and 1.67 for the control group (P=0.80). The CSA of the Achilles tendon was 2.1 (0.46) cm2  in the EFM group and 2.1 (0.30) cm2  in the control group (P=0.086) at one year. There was no significant difference in muscle CSA between the two groups when evaluating the medial and lateral gastrocnemius heads or soleus muscle belly. 

Conclusions: Although early Achilles tendon mobilization resulted in higher ATRS, there were no significant differences in long term tendon elongation, or tendon and muscle CSA. The most notable result was that tendon elongation seemed to be related to weight bearing pattern, with an increase in early mobilization at first. However, there was some question that early elongation was related to inadequate tendon repair. This is important due to the ever evolving nature of improved treatments for Achilles rupture rehabilitation, suggesting that early protected weight bearing gives similar outcomes to delayed weight bearing. 

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