Patients who undergo bilateral medial patellofemoral ligament reconstruction return to sport at a similar rate as those that undergo unilateral reconstruction

Return to Sports Rates in Pediatric Patients After Bilateral Versus Unilateral Medial Patellofemoral Ligament Reconstruction

BACKGROUND

Patellofemoral instability commonly occurs during sports activities. The return to sports (RTS) rate for pediatric patients after bilateral medial patellofemoral ligament reconstruction (MPFLR) is unknown.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate RTS outcomes for pediatric patients undergoing bilateral MPFLR. It was hypothesized that (1) fewer pediatric patients would RTS after bilateral MPFLR compared with unilateral MPFLR and that (2) for those in the bilateral cohort who were able to RTS, fewer patients would attain the same level of play as or higher level than the preinjury level.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We prospectively collected RTS data on retrospectively identified matched cohorts of patients aged ≤18 years who underwent unilateral and bilateral MPFLR. We matched each participant with bilateral MPFLR at a 1 to 2 ratio with a participant with unilateral MPFLR by concomitant procedure, age, and sex. Postoperative complications and preoperative imaging measurements were collected from medical records. Patient-reported outcomes were obtained using a current Single Assessment Numeric Evaluation score collected at the time of primary outcome data.

RESULTS

We matched 16 participants (mean age, 14 years) who underwent bilateral MPFLR to 32 participants (mean age, 14.3 years) in a corresponding unilateral MPFLR cohort. We found a significant decrease in RTS rates for pediatric patients after bilateral MPFLR when compared with unilateral MPFLR (69% vs 94%; P = .03). Among those who returned to sports, there was no difference in the level of play achieved. For participants who did not RTS or returned at a lower level of play after bilateral MPFLR, 57% cited fear of reinjury as the primary reason. There were no differences in postoperative complications or current Single Assessment Numeric Evaluation scores between cohorts. The bilateral cohort had a significantly higher Caton-Deschamps index compared with the unilateral cohort, although the absolute difference was small (1.3 vs 1.2; P = .005).

CONCLUSION

We found that pediatric patients have a lower RTS rate after bilateral MPFLR when compared with a matched unilateral MPFLR cohort. No differences in the level of play were achieved among those who returned to sports. Fear of reinjury was a commonly cited reason for not returning to sports.

Patients who undergo tibial tubercle anteromedialization with medial patellofemoral ligament reconstruction demonstrate similar rates of return to sport compared to isolated MPFL reconstruction

PURPOSE

To investigate the rate of return to sports and sport psychological readiness between patients who underwent isolated MPFLR (iMPFLR) compared to a matched cohort of patients who underwent MPFLR with anteromedializing tibial tubercle osteotomy (MPFLR/TTO).

METHODS

Patients who underwent primary MPFLR with or without TTO for recurrent patellar instability were retrospectively reviewed from 2012 to 2020 at a single institution. Preinjury sport and work information, Kujala, Tegner, Visual Analogue Score for pain, satisfaction and MPFL-Return to Sport after Injury (MPFL-RSI) score were collected. Two readers independently measured the tibial tuberosity-trochlear groove distance, Caton-Deschamps index and Dejour classification for trochlear dysplasia. Patients in iMPFLR and MPFLR/TTO groups were matched 1:1 on age, sex, body mass index and follow-up length. Multivariate regression analysis was performed to determine whether the MPFL-RSI was associated with a return to sport.

RESULTS

This study included 74 patients at mean follow-up of 52.5 months (range: 24-117). These groups returned to sport at similar rates (iMPFLR: 67.6%, MPFLR/TTO: 73.0%, not significant [ns]), though iMPFLR patients returned more quickly (8.4 vs. 12.8 months, p = 0.019). Rates of return to preinjury sport level were also similar (45.9% vs. 40.5%, ns). Patients with Dejour B/C took more time to return to sport compared to patients with mild/no trochlear pathology (13.8 vs. 7.9 months, p = 0.003). Increasing MPFL-RSI score was significantly predictive of the overall return to sport (odds ratio [OR]: 1.08, 95% confidence interval [CI] [1.03, 1.13], p < 0.001) and return to preinjury level (OR: 1.07, 95% CI [1.04, 1.13], p < 0.001). Most patients in iMPFLR and MPFLR/TTO groups resumed work (95.7% vs. 88.5%, ns), though iMPFLR patients who returned to preinjury work levels did so more quickly (1.7 vs. 4.6 months, p = 0.005).

CONCLUSION

Patients who underwent MPFLR with anteromedializing TTO demonstrated similar rates of return to sport and psychological readiness compared to an isolated MPFLR matched comparison group, though iMPFLRs returned more quickly. Patients with more severe trochlear pathology required more time to return to sports.

LEVEL OF EVIDENCE

Level III.

Patients with bilateral patellar instability have multiple and symmetric risk factors in each knee

PURPOSE

Bilateral involvement is common in patients with patellar instability. The management of bilateral patellar instability is associated with increased complication rate. The higher complication rate in this cohort may be related to the presence of underlying anatomic risk factors. The purpose of the study was to evaluate the presence and side-to-side differences in risk factors between knees in bilateral patellar instability.

METHODS

In a retrospective study (2008-2017), demographic information, characteristics of patellar dislocation and anatomic risk factors on MRI (trochlear dysplasia, patellar height, tibial tubercle lateralization, patellar tilt, sulcus angle, bump height) were evaluated in both knees of all patients (n = 32, 15 males and 17 females) with bilateral patellar instability. The risk factors were analyzed based on established cut off values and were compared between gender, laterality and more symptomatic (index) knee. Knee symmetry and absolute differences between risk factors for both knees were analyzed.

RESULTS

The mean age of 32 patients was 14.6 ± 2.3 years. Of the 4 major anatomic risk factors, the most common were trochlear dysplasia in 59/64 (92.1%) knees and patella alta in 51/64 (79.7%) knees. Tibial tubercle lateralization was the least common risk factor being present in 8/64 (12.5%) knees. Of 64 knees, 55 (85.9%) had 2 or more risk factors and 30 (46.8%) had 3 or all 4 risk factors present. There were no significant differences in risk factors based on gender, laterality or index knee. There was symmetry between paired knees for 31/32 (96.8%) patients for trochlear depth, 29/32 (90.6%) for patellar tilt, 27/32 (84.3%) for TT-TG distance and 25/32 (78.1%) for patellar height. There were no significant differences in absolute measurements between knees for any of the risk factors.

CONCLUSION

Patients with bilateral instability had multiple risk factors, with trochlear dysplasia being the most common and increased TT-TG distance being the least common. Majority of patients had 2 or more risk factors and about half had 3 or 4 risk factors in each knee. There was symmetry between paired knees for each risk factor without any significant differences between the index knee compared to the contralateral knee.

LEVEL OF EVIDENCE

Level III.