Post-operative joint stiffness after Bereiter trochleoplasty does not affect 2-year improvement in patient-reported outcomes. A prospective cohort study of 374 Bereiter trochleoplasties.

Purpose: Bereiter trochleoplasty (TP) is a well-described procedure to address trochlear dysplasia (TD). Post-operative joint stiffness with reduced range of motion (ROM) is a common complication usually requiring arthroscopically assisted manipulation (AAM) with the removal of adhesions and scar tissue. Inferior clinical outcomes after TP have been reported for patients with subsequent surgery. We hypothesised that a 2-year improvement in patient-reported outcomes would be lower in patients treated with AAM.

Methods: This was a retrospective cohort study of prospectively collected data comparing subgroups of patients with and without post-operative joint stiffness from a consecutive cohort of 374 knees with high-grade TD who underwent TP according to the Copenhagen patello-femoral instability (PFI) algorithm. All patients received supervised training exercises led by a physiotherapist. At 3-month follow-up, patients with an extension deficit >10° and/or flexion <120° were diagnosed with post-operative joint stiffness and treated with AAM. Outcomes were mean differences from baseline in Kujala, Knee injury and Osteoarthritis Outcome Score (KOOS) and Lysholm scores 1 and 2 years after surgery.

Results: Forty-nine (38 females, 11 males) of the 374 knees (12%) had post-operative joint stiffness and underwent AAM. Nine patients underwent subsequent AAMs. Full extension and flexion >135° were achieved in 37 out of 49 cases (75%). In 11 cases, flexion remained reduced, while data on ROM could not be retrieved in one case. While both patients with and without AAM showed clinically relevant improvements in the Kujala, KOOS and Lysholm scores, no statistically significant between-group differences were seen in these improvements.

Conclusions: Post-operative joint stiffness was a common complication after Bereiter TP following the Copenhagen PFI algorithm. Twenty-five per cent of the AAM patients, or 3% of the study population, did not regain full ROM. We did not find that post-operative joint stiffness was associated with inferior improvements in patient-reported outcomes 1 and 2 years after surgery.

Level of evidence: Level IV, a retrospective cohort study.