[Reconstruction of the patellar tendon with autologous or allogeneic semitendinosus tendon transplant for chronic rupture].

Objective: Reconstruction of a patellar tendon defect in the event of a chronic rupture.

Indications: Chronic rupture of the patellar tendon due to delayed diagnosis or failure of primary refixation with a dehiscence that does not allow for anatomical refixation without patellar tendon shortening.

Contraindications: Infection.

Surgical technique: Approximately 15 cm long incision from the tibial tuberosity to the patella. Depicting the rupture. Debridement of the tendon and insertion. Suture in the quadriceps tendon and distalization of the patella. If sufficient distalization of the patella is not possible, optionally perform a VY-plasty of the quadriceps tendon. Measuring the dehiscence. Securing the height of the patella by applying a patellotibial cerclage (strong suture cord). Extension of an existing tendon stump using a Z-plasty. Creation of 2 bone tunnels (diameter approx. 5 mm) in the patella and the tibial tuberosity. Insertion of an autologous or allogeneic semitendinosus tendon transplant and securing it by knotting the retaining threads in front of the tibial tuberosity.

Postoperative management: Six weeks of partial weight-bearing with 10 kg of body weight in a straight, removable splint. Range of movement: weeks 1-4 E/F 0-0-60°, weeks 5-6 E/F 0-0-90°.

Results: Seven patients who underwent this surgery as described above had a minimum follow-up of 2 years. Secondary lengthening of the quadriceps tendon had to be performed twice due to excessive retraction. All patients were able to perform active extension postoperatively. The Lysholm score rose from 49.3 to 83.2 points. No further rupture was detectable in the final ultrasound examination.