[Proximalization of the tibial tuberosity as a salvage operation of the symptomatic patella baja].

OBJECTIVE

Improvement of flexion and thereby restoration of function of the knee joint as well as pain reduction by proximalization of the tibial tuberosity in combination with arthrolysis and release of the patellar retinaculum.

INDICATIONS

Salvage surgery if conservative or arthroscopic treatment for a patella baja (Canton-Deschamps index < 0.6) has failed, especially in the case of mechanical and pain-related limitation of mobility. The timing for the surgery is crucial; surgery should only be performed after the end of the inflammatory phase and fibrosis of the patella ligament is complete.

CONTRAINDICATIONS

Possible conservative and arthroscopic therapy attempts, local infection, pseudarthrosis, bone defects of the patella, fracture in the area of the tuberosity, active inflammatory process.

SURGICAL TECHNIQUE

Median longitudinal incision. Combined medial and lateral arthrotomy alongside the patellar tendon. Wedge-shaped tuberosity osteotomy over approximately 7 cm. The patella is thereafter reflected proximally to expose the entire knee joint. Extensive open arthrolysis especially of the superior recess and release of the retinaculum. Proximalized refixation of the tuberosity with at least two screws, depending on the preoperative planning and intraoperative movement control. If necessary, lengthening of the medial and lateral retinaculum to completely close the joint.

POSTOPERATIVE MANAGEMENT

Postoperative (post-OP) week 1-6: partial weight bearing 20 kg, knee brace, continuous passive motion (CPM) training, limitation of the range of motion (ROM) to flexion/extension: 90°/0°/0°. Post-OP week 7: additional load of 20 kg per week, free ROM.

RESULTS

The authors followed a series of 7 patients with proximalization of the tibial tuberosity in symptomatic patella baja. The authors recorded pre- and postoperative patient-reported outcome measures with an average follow-up of 3.0 ± 2.6 years (range 0.6-7.6 years). The patients were 43 ± 11 years old (6 women, 1 men). There was a significant improvement in the 2000 International Knee Documentation Committee (IKDC)-subjective score (pre-OP: 40 ± 17 vs. post-OP: 72 ± 10; p = 0.011) and in the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscore for activities of daily living (pre-OP: 20 ± 23 vs. post-OP: 60 ± 20; p = 0.014). The authors were also able to identify a trend towards improvement, particularly in the Kujala score and the KOOS subscores for pain and physical activity; however no significant improvements were observed. These results make it clear that the proximalization of the patellar tuberosity can improve the subjective outcome in symptomatic patella baja.