Operative Anatomy of the Medial Gastrocnemius Recession vs the Proximal Medial Gastrocnemius Recession.

BACKGROUND: Isolated gastrocnemius contracture (IGC) is associated with various foot and ankle pathologies. To address the problem of IGC, a number of gastrocnemius lengthening procedures have been described. Although proximal medial gastrocnemius recession (PMGR) has shown to be an effective operative treatment for IGC, it poses risks to various anatomic structures around the knee joint and requires the patient to be positioned prone. As an alternative, we proposed to release the medial gastrocnemius at the division between the proximal one-third and distal two-thirds of the gastrocnemius muscle to correct equinus contracture, while minimizing risk to other structures. The aim of this study was to describe an anatomic basis for a medial gastrocnemius recession (MGR) and to investigate the anatomic structures at risk in comparison to PMGR.

METHODS: Eight cadaveric lower leg specimens were used in the study. The standard PMGR and the novel MGR were performed on each specimen. After completion of the 2 procedures, complete dissection was performed to investigate the distances between surgically released fascia margins and surrounding anatomic structures, including the greater saphenous vein, small saphenous vein, saphenous nerve, medial sural cutaneous nerve, semimembranosus tendon, tibial nerve, and popliteal artery. The mean distances were calculated and the shortest distances for each structure were reported.

RESULTS: Proximities of anatomic structures to surgically released gastrocnemius fascia at the medial and lateral margins were notably different between the 2 techniques. For the PMGR, the semimembranosus tendon (95% confidence interval of 2.4-7.4 mm), small saphenous vein (3.4-10.0 mm), popliteal artery (3.9-9.3 mm), and tibial nerve (5.0-11.1 mm) were in greater proximity to the operative margin. For the MGR, the greater saphenous vein (5.3-17.6 mm) and saphenous nerve (5.1-18.6 mm) were at greater risk.

CONCLUSIONS: MGR at the proximal one-third of the gastrocnemius muscle may be a safe alternative for operative treatment of IGC.

CLINICAL RELEVANCE: We identified the major structures at risk when performing the proximal medial gastrocnemius release and propose a novel, possibly safer alternative for the medial gastrocnemius release.