2023 ISAKOS Biennial Congress ePoster
Functional Outcomes after Medial Patellofemoral Ligament Reconstruction is Influenced By Body Mass Index
Saket Raj Bonde, M.S. Orthopedics, Wigan, Greater Manchester UNITED KINGDOM
Nik Sharma, MBChB, PgCert MedEd, DipFM, MFSTEd, FRCS (Tr&Orth), Wolverhampton UNITED KINGDOM
Jan Herman Kuiper, M.Sc. Ph.D., Oswestry UNITED KINGDOM
Peter Gallacher, MBChB, MRCS, FRCS(Tr & Orth), Oswestry UNITED KINGDOM
Andrew Barnett, MBBS, MRCS(Ed), FRCS(Ed)(Tr&Orth), Shrewsbury UNITED KINGDOM
Robert Jones and Agnes Hunt Orthopaedic Hospital, Gobowen, Oswestry, Shropshire , UNITED KINGDOM
FDA Status Not Applicable
Summary
A BMI of 20.5 is associated with peak functional outcomes following a medial patellofemoral ligament reconstruction
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Abstract
Aims
Medial patellofemoral ligament reconstruction is a recognised surgical procedure for the treatment of recurrent patellofemoral instability with excellent outcomes reported. The aim of this study is to determine if body mass index can influence these outcomes.
Methods
This is a single centre prospective analysis of a longitudinal patellofemoral database. Between 2015 and 2019, 97 patients (97 Knees) were surgically treated with an isolated medial patellofemoral ligament reconstruction. Surgery was performed by two fellowship trained sports knee surgeons at The Robert Jones & Agnes Hunt Orthopaedic Hospital. The indication for surgery in each case was recurrent, two or more episodes of patellar instability. The Oswestry Patellotrochlear Algorithm, which combines the OBC and Patellotrochlear index was used to guide the choice of surgical treatment. Exclusion criteria included patients who underwent additional concomitant procedures such as tibial tubercle osteotomy, trochleoplasty or revision procedures and those whose BMI had not been recorded at the time of surgery. All patients had a minimum of 1-year follow-up.
The clinical efficacy following surgery was assessed by Kujula, IKDC and EQ-5D scores at baseline and up to 26 months post-operatively; their safety assessed by complication rate and requirement for further surgery. The effect of BMI on clinical outcome was analysed using linear, curvilinear, and segmented models following propensity-score weighting.
Results
A total of 97 patients (97 Knees, mean age 25y) were analysed. Of these, 61 patients had a BMI <30kg/m2 (mean age 23y, mean BMI 24) of which 7 patients (12.3%) required additional surgery. A further 36 patients had a BMI >30kg/m2 (mean age 27y, mean BMI 36) of which 2 patients (5.6%) required additional surgery. The re-dislocation rate was 0% in each BMI group. Both groups had a significantly improved mean outcome following surgery, with improvements in mean IKDC above the MCID of 20.5. BMI had an inverted J-shaped association with functional outcome, showing peak outcomes at BMI=20.5 (IKDC and Kujala) or BMI=28 (EQ-5D index). No evidence for an association between BMI and complication risk was found.
Conclusion
BMI affects the functional outcomes in MPFLr with an inverted J-shaped relation, without evidence it affected the complication or re-dislocation rate. In the absence of patella alta and severe trochlear dysplasia, an isolated MPFL reconstruction is a safe and effective procedure to treat patellar instability, with the best functional outcome in patients with a BMI=20.5.