RESUMEN
PURPOSE: To investigate whether the patellotrochlear index (PTI) predicts patella alta as determined by tibial-based methods of Insall-Salvati (IS) and Caton-Deschamp (CDI) indexes in a pathological population (with patellofemoral pain and/or instability), in addition to determining whether PTI and sagittal patellofemoral engagement (SPE) correlate with trochlea length as determined by lateral condyle index (LCI). METHODS: Patients with confirmed patella alta (IS/CDI ratio >1.2) undergoing tibial tubercle osteotomy for patellofemoral pain/instability with an available magnetic resonance imaging (MRI) scans were included. Patients who had undergone previous soft-tissue realignment, previous surgery, or trauma to the extensor mechanism were excluded. Two raters measured the IS, CDI, PTI, SPE, LCI, and knee flexion angle (KFA) on MRI. Interobserver reliability and correlation between measurements were calculated. RESULTS: In total, 71 knees were included. PTI (0.73), SPE (0.836), LCI (0.701), and KFA (0.8) demonstrated good- to near-excellent interobserver reliability. IS (0.65) and CDI (0.66) demonstrated moderate interobserver reliability. PTI and SPE showed the strongest significant correlation (0.8112, P = 2.2 × 10-16). IS and CD (0.39, P = .0007) showed a moderate significant correlation. PTI and KFA (0.53, P = 1.685 × 10-6) and SPE and KFA (0.61, P = 1.991 × 10-8) had a significant moderate correlation. LCI and KFA (-0.37, P = .0017) showed a significant moderate negative correlation. All other measurement indices correlated poorly and were insignificant. A total of 94.4% of the knees were defined as having patella alta using IS, with the remaining 5.6% having a raised CDI. Only 14% of cases had an IS of >1.2, a CDI >1.2, and a PTI <0.125, which increased to 39% (28/71) when the threshold for PTI was increased to <0.28. CONCLUSIONS: There was no correlation between tibial (IS and CD) and femoral methods (PTI and SPE) of quantifying patella alta. PTI and SPE did not correlate with trochlea length as measured by LCI. PTI, SPE, and LCI are significantly affected by the KFA during MRI. LEVEL OF EVIDENCE: Level IV, retrospective diagnostic radiographic investigation.
RESUMEN
BACKGROUND: Thicker (folded) facia lata autografts have been shown to be superior to thinner grafts and single-layered acellular human dermal (HD) allografts for superior capsular reconstruction (SCR) in biomechanical studies. The aim of this study was to evaluate the midterm clinical outcomes following SCR for irreparable supraspinatus tears using doubled (folded) HD allograft. METHODS: Thirty-two patients who had undergone SCR using doubled HD allograft between February 2012 and January 2020 were recruited in a continuous manner in this retrospective study. The inclusion criteria were SCR performed for irreparable supraspinatus tear and a minimum of 2 years' follow-up. The primary outcome measure was the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score. The secondary outcome measures were complications and revision surgery. A subgroup analysis was performed between patients who received a "standard" graft of mean 3-mm thickness or a "thick" graft of mean 4.4-mm thickness. RESULTS: One patient was lost to follow-up. A total of 31 patients (31 shoulder joints) were analyzed with a mean follow-up duration of 48 months (range, 25-96 months). Following surgery, there was significant improvement in the ASES score from 18.1 ± 14.3 (preoperative) to 76.3 ± 25.1 (postoperative) (P < .001), with a satisfactory clinical outcome obtained in 83.8% of the patients. In a subset of 8 patients completing 5 years' follow-up, the clinical improvements were sustained. The percentage of patients with a clinically successful outcome was higher among those with thick grafts compared to those with standard grafts, although this failed to reach statistical significance (94.4% vs. 69.2%, risk ratio 1.36, 95% confidence interval 0.93-1.99, P = .13). One patient within the standard group underwent revision surgery. CONCLUSION: SCR for irreparable rotator cuff tears with doubled HD allograft results in improved clinical outcomes and low reoperation at midterm follow-up duration.