The clinical and radiological results of individualized surgical treatment depending on pathologic abnormalities in recurrent patellar dislocation: low recurrence rate, but unintended patella baja

Abstract

Purpose: To evaluate the clinical and radiological outcomes and chondral lesion change using individualized surgery for recurrent patellar dislocation.

Methods: A total of 31 knees with recurrent patellar dislocation underwent surgery depending on individual pathologic abnormalities. Pathologic abnormalities including medial laxity, lateral tightness, increased tibial tuberosity (TT)-to-trochlear groove distance (>20 mm), and patella alta (Caton-Deschamps ratio >1.2) were evaluated in each patient. The abnormalities were corrected through medial patellofemoral ligament reconstruction, TT distalization, TT anteromedialization, and lateral retinacula release. The mean follow-up period was 33 months.

Results: There was one recurrent case (3.2%), requiring additional surgery. The mean Kujala scores were significantly (P = 0.002) improved from 75.8 (SD 12.4) to 84.6 (SD 13.1). Tegner scores were significantly improved from 3.7 (range 1-9) to 5.4 (range 2-9) (P < 0.001), as were and visual analogue scale pain scores from 4.7 (SD 2.5) to 2.6 (SD 2.2) (P = 0.001). Caton-Deschamps ratio was significantly decreased from 1.1 (SD 0.2) to 0.9 (SD 0.1) (P < 0.001), regardless of TT distalization. Chondral lesions of the patella and trochlear groove were improved or maintained in 57.1 and 71.4% of patients, respectively.

Conclusion: Individualized surgery in recurrent patellar dislocation was effective and safe with a low recurrence rate. However, the possibility of unintended patella baja, which might be related to post-operative anterior knee pain, should be considered.

Level of evidence: IV.

Keywords: Individualized surgery; Lateral retinacula release; Medial patellofemoral ligament reconstruction; Recurrent patellar dislocation; Tibial tuberosity anteromedialization; Tibial tuberosity distalization.