Extensor function after medial gastrocnemius flap reconstruction of the proximal tibia

Area of Science:

• Orthopedic Surgery
• Musculoskeletal Oncology
• Reconstructive Surgery

Background:

• Reconstructing the extensor mechanism after proximal tibia resection presents challenges.
• Medial gastrocnemius flaps are common but may cause extensor lag.
• The long-term development and functional correlation of extensor lag are not well understood.

Purpose of the Study:

• To assess changes in patellar height over time post-reconstruction.
• To correlate patellar height with functional outcomes using the Musculoskeletal Tumor Society (MSTS) score.
• To evaluate the relationship between patellar height and range of motion (ROM).

Main Methods:

• A cohort of 16 patients undergoing proximal tibia tumor resection and extensor mechanism reconstruction with a medial gastrocnemius flap was studied.
• Patellar height was monitored radiographically using the Blackburne-Peel Index.
• Functional outcomes were assessed retrospectively via MSTS scores, active extensor lag, and flexion.

Main Results:

• Patella alta developed in 11 patients, stabilizing around 2 years post-surgery.
• Higher patellar height correlated with worse MSTS scores and increased extensor lag (mean 17° vs 4°).
• Patients with patella alta had greater flexion (mean 94° vs 77°) but also a more significant extensor lag.

Conclusions:

• Patella alta evolves within the first two postoperative years following medial gastrocnemius flap reconstruction.
• The development of patella alta is associated with increased extensor lag, reduced range of motion, and poorer functional scores.
• Consideration of distal patellar tendon fixation or postoperative bracing may be beneficial.