Publication:

Arthroscopically assisted medial plication combined with lateral retinaculum release in cases of lateral patellar instability in comparison with medial patellofemoral ligament reconstruction: a short term comparative study

Background The stability of patellofemoral joint in a healthy knee depends on bony structure of the joint and multiple static and dynamic soft tissue structures. Of them, the most important structure is the medial patellofemoral ligament (MPFL). The aim of this study is to evaluate the results of the arthroscopically assisted medial plication and lateral retinacular release in cases of lateral patellar instability in comparison to medial patellofemoral ligament reconstruction in a short term follow up study in patients with no or minimal bony deformities.

Methods This prospective randomized comparative clinical study was conducted on 40 patients with lateral patellar instability attending the Orthopedic Clinic at Benha University Hospital. Patients were randomly divided into two equal groups: group I (n=20) underwent arthroscopic medial retinaculum plication with lateral retinaculum release, and group II (n=20) underwent open MPFL reconstruction using a gracilis tendon graft. All patients underwent standardized clinical, and radiological assessment. Outcomes included operative time, complications, hospital stay, time to mobilization and weight bearing, radiological patellar tracking, and functional outcomes assessed by western Ontario and McMaster universities osteoarthritis index (WOMAC) and Lysholm scores over 6-24 months.

Results There were no significant differences between both groups regarding baseline or radiological data. However, group II showed significantly longer operative time, greater perioperative blood loss, and longer hospital stay. Although re-dislocation and patellar instability rates were higher in group I (10% and 20% versus 0% and 5% in group II), the differences were not significant, with a non-significant higher failure rate in group I (p=0.091). Postoperatively, group II demonstrated significantly greater radiological improvement, earlier mobilization, and superior functional outcomes with higher Lysholm and lower WOMAC scores at follow-up (p<0.05 to p<0.001).

Conclusions MPFL reconstruction yields better patellar alignment and functional outcomes with lower re-dislocation and instability rates and greater radiological improvement than arthroscopic medial plication with lateral release, but it is associated with longer operative time and increased blood loss.