Surgical technique: Muscle transfer restores extensor function after failed patella-patellar tendon allograft

Area of Science:

• Orthopedic Surgery
• Musculoskeletal Reconstruction
• Biomedical Engineering

Background:

• Extensor mechanism allograft is used for severe quadriceps deficiency after total knee arthroplasty (TKA).
• Late allograft failure is common, leading to significant quadriceps deficiency.
• Reconstruction options after allograft failure are limited.

Purpose of the Study:

• To evaluate the feasibility of a novel muscle transfer technique for reconstructing the extensor mechanism after allograft failure in TKA.
• To assess the potential of using native muscles to restore knee extensor function.

Main Methods:

• Dissection of six human cadaver specimens to assess muscle transfer viability.
• Transfer of vastus medialis, vastus lateralis, and medial gastrocnemius muscles to reconstruct the extensor mechanism.
• Clinical application in five patients with failed patellar tendon allografts.

Main Results:

• The medial gastrocnemius muscle provided secure closure and strong tendon attachment.
• Mean extensor lag improved significantly from 47° pre-operatively to 12° at 1 year post-operatively.
• The technique successfully salvaged failed extensor mechanism allografts.

Conclusions:

• The described muscle transfer technique offers a potential salvage option for failed extensor mechanism allografts after TKA.
• This approach may restore knee extensor function in patients with severe quadriceps deficiency.
• Further investigation is warranted to confirm long-term efficacy.