Compared outcomes 16 and 25 years after lateral wedge augmentation trochleoplasty: Rate of recurrent dislocation and progression to osteoarthritis.

BACKGROUND

Lateral wedge augmentation trochleoplasty (LWAT) was the earliest described trochleoplasty technique but was gradually replaced by other methods for the treatment of patello-femoral instability with trochlear dysplasia. Data on the outcomes of this procedure in adults are limited. We therefore performed a retrospective study in patients managed by LWAT to assess (1) clinical (recurrent instability and functional scores), (2) and radiological (patello-femoral osteoarthritis) outcomes.

HYPOTHESIS: LWAT is associated with a low long-term rate of recurrent patello-femoral dislocation and with no risk of progression to severe patello-femoral osteoarthritis.

MATERIAL AND

METHODS

Between 1988 and 1995, LWAT was performed on 66 knees in 58 patients to treat patello-femoral instability with trochlear dysplasia. Among them, 17 knees in 13 patients were re-evaluated 16 then 25 years after surgery and were included in the study. At both time points, the following were recorded: stability, pain, the Lille patello-femoral function score, and changes in radiographic and computed tomography findings. In addition to LWAT, Insall's realignment vastus medialis advancement was performed in 4 cases, sartorius muscle transposition in 9 cases, and anterior tibial tubercle osteotomy in 10 cases.

RESULTS

No episodes of patello-femoral dislocation were recorded during the 25-year follow-up. The mean Lille patello-femoral function score (0 worst to 100 highest) was 90±15 (range, 48-99) after 16 years and 86±23 (range, 33-94) after 25 years. After 16 years, 8/17 knees had evidence of patello-femoral osteoarthritis, which was Iwano stage 1 in 7 cases and Iwano stage 2 in 1 case. Patello-femoral osteoarthritis was noted in 12 of 13 knees after 25 years but was mild (Iwano stage 1 or 2) in 8 cases. After 25 years, arthroplasty had been performed for 4 of the 17 knees, with 2 cases each of patello-femoral arthroplasty and total knee arthroplasty.

CONCLUSION

LWAT is a reliable procedure that provides sustained protection against patello-femoral dislocation and good functional scores when used to treat patello-femoral instability due to trochlear dysplasia. Our results do not support claims that LWAT may be associated with high rates of severe osteoarthritis even after more than 20 years.

LEVEL OF EVIDENCE: IV, retrospective observational study with no control group.