Patellar tendon tenodesis in association with tibial tubercle distalization for the treatment of episodic patellar dislocation with patella alta.

BACKGROUND: The association between patella alta and episodic patellar dislocation (EPD) has been well described, but its pathophysiology is not completely clear. Patella alta causes decreased contact between the patella and trochlea and decreased resistance to lateral translation of the patella. Additionally, increased patellar tendon length may allow pathologically increased coronal plane patellar motion. It may thus be desirable to address the length of the patellar tendon itself rather than just its insertion site.

HYPOTHESIS: Tenodesis of the patellar tendon in association with tibial tubercle distalization in patients with EPD and abnormally long patellar tendons (>52 mm) results in significant reduction in patellar tendon length, prevention of further patellar dislocation, and good knee function at long-term follow-up.

STUDY DESIGN: Case series; Level of evidence, 4.

METHODS: Twenty-seven knees in 22 patients with EPD and patella alta were treated with patellar tendon tenodesis and tibial tubercle distalization. Following tubercle distalization, the patellar tendon was tenodesed into the original location of the tibial tubercle with suture anchors. Changes in patellar tendon length and patellar height were measured radiographically. Any recurrent dislocation was documented, and patients completed an International Knee Documentation Committee (IKDC) subjective form at a mean of 9.6 years (range, 6-14 years) after surgery.

RESULTS: The mean length of the patellar tendon decreased from 56.3 ± 2.7 mm to 44.3 ± 8.6 mm (P < .0001). The Caton-Deschamps index decreased from 1.22 ± 0.17 to 0.95 ± 0.22 (P < .0001), and the Insall-Salvati ratio decreased from 1.42 ± 0.17 to 0.91 ± 0.18 (P < .0001). No patellar dislocations occurred postoperatively. The mean postoperative subjective IKDC score was 75.6 ± 9.5.

CONCLUSION: Patellar tendon tenodesis and tibial tubercle distalization result in normalization of patellar tendon length, a stable patellofemoral joint, and good long-term knee function in patients with patella alta and EPD.