Isolated Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability Regardless of Tibial Tubercle-Trochlear Groove Distance and Patellar Height: Minimum 5-Year Outcomes.

BACKGROUND

It remains unclear which subset of patients with recurrent patellofemoral instability would benefit from a concomitant bony realignment procedure in addition to a medial patellofemoral ligament (MPFL) reconstruction.

PURPOSE

To provide midterm results for patients who underwent an isolated MPFL reconstruction as part of an ongoing prospective trial.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients with recurrent patellar instability were prospectively enrolled in an institutional registry beginning in March 2014. Exclusion criteria included history of a previous surgery for patellar instability, an off-loadable (inferior/lateral) chondral defect, anterior knee pain ≥50% of their chief complaint, and a "jumping J" sign. All patients underwent primary, unilateral, isolated MPFL reconstruction regardless of their bony anatomic characteristics. Patient-reported outcome measures (PROMs), episodes of recurrent instability, and ability to return to sport were obtained annually. Radiographic measurements of baseline radiographs and MRI were obtained at baseline.

RESULTS

A total of 138 patients underwent isolated MPFL reconstruction between March 2014 and December 2019. The mean radiographic measurements were tibial tubercle-trochlear groove, 15.1 ± 4.9 mm; Caton-Deschamps index, 1.14 ± 0.16; patellar trochlear index, 46.9% ± 15.1%; trochlear depth index, 2.5 ± 1.2 mm; tibial tubercle to lateral trochlear ridge, -8.4 ± 5.7 mm; and patellar tendon to lateral trochlear ridge, 5.7 ± 6.2 mm. Trochlear dysplasia, defined as a trochlear depth index <3 mm, was present in 79/125 (63%) patients. A total of 50 patients reached ≥5 years, of whom 40 (80%) completed follow-up PROMs. A total of 119 patients reached ≥2 years, of whom 89 (75%) completed follow-up PROMs. Six patients (5%) reported recurrent instability with a mean time of 2.97 years after surgery. All PROMs improved over time except for the Pediatric Functional Activity Brief Scale (Pedi-FABS), which had no change. At 2 years, the mean changes from baseline for Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life subscale (QOL), Pedi-FABS, International Knee Documentation Committee (IKDC) score, KOOS Physical Function Short Form (PS), and Kujala score were 42.1, 0.6, 35.1, -23.5, and 32.3, respectively. All changes had

CONCLUSION

Midterm outcomes for patients who underwent isolated MPFL reconstruction were favorable and were maintained at 5 years. Outcomes for the expanded cohort of patients with a minimum 2-year follow-up support previously published results.

Déclaration de conflit d'intérêts

One or more of the authors has declared the following potential conflict of interest or source of funding: E.R.D. has received support for education from Gotham Surgical Solutions & Devices, Arthrex, and Smith & Nephew and has received consulting fees from CONMED. B.J.E. has received support for education from Arthrex, Smith & Nephew, Pinnacle, and Gotham Surgical; and consulting fees from Arthrex and DePuy Synthes. J.M.B. has received consulting fees from Miach, support for education from Steelhead Surgical and Arthrex, and speaking fees from Smith & Nephew. B.E.S.S. has received consulting fees from Arthrex and research support from CONMED; her spouse has received consulting fees and royalties from Arthrex. She is on the Medical Publishing Board of Trustees for the AOSSM. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.