SLR - October 2017 - Cason M. Quinn

Soleus Atrophy Is Common After the Nonsurgical Treatment of Acute Achilles Tendon Ruptures: A Randomized Clinical Trial Comparing Surgical and Nonsurgical Functional Treatments

Reference: Heikkinen J, Lantto I, Flinkkila T, Ohtonen P, Niinimaki J, Siira P, Laine V, Leppilahti J. Soleus Atrophy Is Common After the Nonsurgical Treatment of Acute Achilles Tendon Ruptures: A Randomized Clinical Trial Comparing Surgical and Nonsurgical Functional Treatments. Am J Sports Med. 2017 May;45(6):1395–1404.

Scientific Literature Review

Reviewed By: Cason M. Quinn, DPM
Residency Program: New York Presbyterian Queens, Flushing, New York

Podiatric Relevance: Surgical and nonsurgical treatment of Achilles tendon ruptures (ATRs) have both been shown to yield good clinical outcomes. However, recent randomized clinical trials comparing treatment groups suggest surgical treatment of ATR leads to earlier rehabilitation and faster and more complete calf muscle recovery. The primary objective of this study was to see whether defects of calf muscle and Achilles tendon found on Magnetic Resonance Imaging (MRI) corresponded with calf muscle strength deficits and to compare the difference between acute surgical versus nonsurgical Achilles tendon rupture treatment groups.

Methods: A randomized controlled trial compared surgical versus nonsurgical treatment of ATRs from 2009 to 2013. Inclusion criteria consisted of 60 adult patients who sustained complete acute ATRs. Patients were allocated to a randomized treatment group: immediate nonsurgical treatment or surgical treatment within 24 hours after randomization. Postoperative protocol was identical to nonsurgical protocol. MRI was performed on both affected and nonaffected limbs at three and 18-month follow-ups. Primary outcome measure was calf muscle volume, obtained using standardized quantitative MRI measurement of calf muscle cross-sectional area for both affected contralateral legs. Secondary outcome measures included Achilles tendon length and muscle fatty infiltration. Calf muscle isokinetic strength was measured at three-, six- and eight-month follow-ups. Measured variables of isokinetic strength were peak torque [Newton meters (Nm)] and ankle-specific torques (Nm) at zero, 10 and 20 degrees of plantarflexion.

Results: Surgical and nonsurgical ATR treatment groups had no difference in calf muscle volume at three months. However, at 18 months, mean side-to-side deficits (calf muscle volume of the affected leg subtracted from that of the unaffected leg) in soleus muscle were 83.2 cm3 (17.7 percent) for the surgical group, 115.5 cm3 (24.8 percent) for the nonsurgical group, with a mean difference of 33.1 cm3. At three months, there was no difference between muscle volumes or fatty degeneration between study groups. Between three and 18 months, compensatory hypertrophy was observed in the flexor hallucis longus (FHL) and deep flexors for both groups. At 18 months, both groups displaced a 21.3 percent difference between healthy and affected legs. At 18 months, soleus muscle volume side-to-side atrophy correlated with calf muscle isokinetic strength deficits, measured as peak torque (P = 0.001). Soleus atrophy also correlated significantly with this deficit at all degrees of ankle motion (P < 0.001). Patients treated nonsurgically had greater fatty degeneration and exhibited lower soleus muscle volumes. The difference between means of Achilles tendon lengths at 18 months for both groups was 18.7 mm, demonstrating increased tendon length in the nonsurgical group compared to surgical group.

Conclusion: Nonsurgical treatment of acute ATRs results in greater soleus muscle atrophy compared to surgical treatment, using identical rehabilitation protocol. The greater mean Achilles tendon length of 19 mm with nonsurgical treatment suggests greater tendon elongation observed was in part responsible for soleus atrophy. Soleus muscle atrophy was compensated with hypertrophy of FHL and deep flexors for both treatment groups; however, the surgical group increased calf muscle isokinetic strength by 10 to 18 percent after 18 months.

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