Summary
Deepening trochleoplasty yielded satisfying results, irrespective of patient age at the time of surgery, indicating that age should play a subordinate role in the clinical decision-making process toward surgical correction of severe trochlear dysplasia.
Abstract
Background
Lateral patellar dislocation typically occurs in young and active patients but might also affect patients over 30 years of age. Currently, conflicting reports regarding the influence of age at the time of surgery and postoperative patient-reported outcome measures (PROMs) have been reported. In particular, the deepening trochleoplasty procedure has been considered to be reserved for young patients with respect to the integrity and flexibility of the trochlear cartilage. However, there is a shortage of clinical data evaluating the results of trochleoplasty procedures in ‘older’ patients. We hypothesized that patients over 30 years of age at the time of tailored surgery for recurrent patellar instability, including deepening trochleoplasty, would achieve similar PROMs as patients under age 30.
Methods
This retrospective cohort study used a prospectively maintained database. A chart review was performed to identify patients who underwent deepening trochleoplasty as part of a tailored surgical treatment plan for recurrent patellar instability between 2015 and 2019. The data included patient demographics, anatomical risk factors and surgical procedures. The Banff Patella Instability Instrument 2.0 (BPII 2.0) and a numerical analog scale (NAS 0-10) for patellofemoral pain (PFP) and subjective knee joint function were used to assess patients’ disease-specific quality of life before and after surgery. Preoperative cartilage status was evaluated via the semiquantitative ‘Area Measurement and Depth & Underlying Structures cartilage evaluation’ (AMADEUS) scoring system. Differences between groups were evaluated with the Mann‒Whitney test, and unpaired t tests and linear regression were used to correlate ‘age’ at the time of surgery with postoperative PROMs.
Results
A total of 156 patients underwent deepening trochleoplasty within the study period. Twenty-nine (18.6%) patients (m/f 4/25) were ≥ 30 years of age (mean 35.3 years; range 30–51) and formed the study group (SG), and 127 (81.4%) patients (m/f 39/88) were < 30 years of age (20.4 years; range 11–29) and formed the control group (CG). The evaluation was performed at a mean of 30 ± 13.2 months (SG) and 33.1 ± 13.3 months (CG) postoperatively (p=0.27). The BPII 2.0 score increased from 48.7 ± 21.4 points to 85.4 ± 10.7 points (p<0.0001) (SG) and from 44 ± 20.6 points to 78.6 ± 18.4 points (p<0.0001) (CG), without any significant difference between the groups at the final follow-up (p=0.24). PFP and subjective knee joint function also improved significantly in both groups (p<0.0001; p<0.0001), again without any significant difference between the groups at the final follow-up (p=0.08; p=0.3). No correlation was found for ‘age’ or any evaluated postoperative PROM (all r2<0.1; p>0.1). The preoperative AMADEUS scores were 80.1 ± 15 points (CG) and 82.1 ± 14.2 points (SG) (p=0.57).
Conclusion
Deepening trochleoplasty, as part of a tailored surgical treatment plan for recurrent patellar instability, yielded satisfying results, irrespective of patient age at the time of surgery. Patient age should therefore play a subordinate role in the clinical decision-making process toward surgical correction of severe trochlear dysplasia.