[Surgical treatment for chronic rupture of the quadriceps tendon]

Reconstruction of the quadriceps tendon to restore extensor function in cases of chronic rupture.

Rupture of the quadriceps tendon due to delayed diagnosis, failure of primary refixation or after implantation of a knee endoprosthesis.

Infections.

Reopen the old incision and verify whether the quadriceps tendon can be reattached to the patella. If there is no dehiscence, refixation with bone anchors (no bone defects) or transosseously (bone defects). If the tissue quality is poor (e.g., previous surgery, knee prosthesis), augmentation with local VY turnover flap, tubular autologous or allogeneic tendon graft or with a synthetic mesh. If the dehiscence is < 5 cm, a VY lengthening flap is recommended. For defects > 5 cm, an allogeneic Achilles tendon graft is used; if the patella is absent an allogeneic extensor graft is used. In cases of significant patella infera (Caton Index < 0.5), either a needling, a Z-plasty to lengthen the patellar tendon (2-3 cm length) or proximalization of the tibial tubercle is performed.

In cases of refixation with augmentation, 6 weeks of partial weight-bearing (10 kg body weight) in a straight removable splint. Range of motion: 4 weeks 0‑0-60, 5-6 weeks 0‑0-90. In cases of augmentation (total knee arthroplasty): Partial weight-bearing of 10 kg body weight is permitted for 6 weeks in a straight removable brace. Subsequently, the patient transitions to an articulated brace for another 6 weeks with progressive range of motion limitations as follows: weeks 7-8: 0‑0-30°, weeks 9-10: 0‑0-60°, weeks 11-12: 0‑0-90°. Thereafter, unrestricted motion is allowed, and the brace may be discontinued.

To date, only small case series have been published on all techniques for managing chronic quadriceps tendon injuries, which were summarized in three systematic reviews. In the native knee refixation with or without augmentation can achieve good clinical results with low rerupture rates. High revision rates and unsatisfactory functional outcomes have been reported after the use of larger allogeneic grafts (Achilles tendon or extensor tendon), therefore these procedures should only be used when large defects cannot be reconstructed using other techniques.