Medial facet patelloplasty in patellar instability associated with patellofemoral dysplasia: a report of 26 cases.

INTRODUCTION

Numerous procedures may be used in the surgical treatment of patellar instability. We have noticed that certain types of patellar instability result in a bulge (or protrusion) of the distal medial facet of the patella which can hinder recentering in the trochlear groove.

HYPOTHESIS: In certain patellofemoral dysplasias, trimming down of this bulge (patelloplasty) as long as it is associated with a "à la carte surgery" program, can improve stability, centering and lateral patellar tilt.

PATIENTS AND

METHODS

This retrospective series included 23 patients (26 knees), 13 women and 10 men, mean age 25.9±9.01 years old (15-52) operated between 1997-2008. Patellar dislocation had occurred at least once in all knees, and at least twice in 16 knees. The mean preoperative Kujala score was 79.1±6.1 points (68-91). There was a bulge on the medial facet of the patella in all cases, in particular on skyline views associated with the usual criteria for patellofemoral dysplasia. Patelloplasty was associated in all cases with resection of the lateral patellar retinaculum and anteromedialization of the tibial tubercle (7 were lowered) and four Albee trochleoplasties.

RESULTS

Recurrent dislocation occurred in one case (4.7%). Nineteen patients (22 knees) were followed up for a mean 7.53±3.27 years (2-13 years). The mean postoperative Kujala score was 91.8±7.9 points (70-100) and the subjective results in 19/22 (86.5%) knees were satisfactory or very satisfactory. On skyline views, 21 patellae (95.5%) were well centered and one (4.5%) still presented with lateral tilt. There was no osteoarthritis in 15 knees (68%).

CONCLUSION

In selected cases, patelloplasty of the medial facet of the patella has no particular morbidity at intermediate follow-up. Associated with other surgical procedures, the rate of satisfaction of patients is very high and especially encouraging.

LEVEL OF EVIDENCE: Level IV, retrospective cohort study.