Functional deficits and significant patellofemoral chondral deterioration two years after trochleoplasty and medial patellofemoral ligament reconstruction.

Purpose: Patellofemoral instability is a common knee condition and often associated with trochlear dysplasia. Sulcus-deepening trochleoplasty is a surgical option to reshape the trochlear groove and stabilise the patella. Although this procedure is considered safe and effective, the development of postoperative patellofemoral chondral lesions remains a topic of concern. The aim of this study was to evaluate the clinical and radiological outcomes following combined trochleoplasty and medial patellofemoral ligament reconstruction with a minimum follow-up of 2 years.

Methods: We assessed 23 patients (24 knees) who underwent trochleoplasty with concomitant medial patellofemoral ligament reconstruction between January 2014 and July 2018 at our institution. Follow-up consisted of clinical assessment, patient related outcome measurements (Kujala, Tegner, and IKDC score), standardised strength assessment using the VALD Performance system and radiological assessment with conventional radiographs and magnetic resonance imaging.

Results: No recurrent patellar dislocation occurred postoperatively. The median postoperative Tegner, Kujala, and IKDC subjective scores were 4 (range 2-8), 87 (range 60-100) and 83 (range 49-98), respectively. Maximal isometric quadriceps (p < 0.001) and hamstring (p < 0.001) strength, as well as performance on the side hop test (p = 0.01), were significantly reduced on the operated side. Postoperative magnetic resonance imaging showed no evidence of chondrolysis or subchondral necrosis. However, chondropathy in the patellofemoral joint significantly worsened. While cartilage status remained stable in six knees, deterioration was observed in 18 knees and it was not significantly associated with the duration of follow-up (p = 0.96) or the preoperative status of the cartilage (p = 0.84).

Conclusion: Trochleoplasty with concomitant medial patellofemoral ligament reconstruction is an effective and safe treatment option for patellofemoral instability in the setting of high-grade trochlear dysplasia. However, functional deficits and significant patellofemoral chondral deterioration were observed with a minimum 2-year follow-up.

Level of evidence: Level IV.