Summary

This study aims to compare the short-term clinical outcomes of medial patellofemoral ligament reconstruction (MPFLR) using superficial quadriceps tendon (SQ) and using hamstring tendon (ST), and both grafts had good short-term results, but concerning patellar complications occurred in the ST autograft, SQ autograft may be safe and considerable for MPFLR.

Abstract

Introduction

While hamstring autografts are widely used in medial patellofemoral ligament reconstruction (MPFLR), the superficial quadriceps tendon (SQ) has also been used presently regarding complications associated with the patella bone tunnel and fixation hardware. To date, few studies have evaluated the comparison of clinical outcomes between the grafts. This study aims to compare the short-term clinical outcomes of MPFLR using superficial quadriceps tendon and using hamstring tendon.

Methods

All patients who had undergone MPFLR for patella instability from 2009 to 2020 and were able to follow up for more than two years were retrospectively evaluated. For autograft of MPFLR, hamstring was inserted to the patellar bone tunnel formed at superomedial corner of the patella or through the whole patella (ST group), while the center third of the superficial layer of the quadriceps tendon graft was harvested and turned medially leaving its attachment to the patella intact (SQ group). Both grafts were fixed at Schottle’s point with an initial tension of 10-20 N and 30 degrees of knee flexion. Preoperative assessment included the range of knee motion (ROM), and radiographic features such as tibial tubercle–trochlear groove (TT-TG) distance, patellar tilt, and sulcus angle. The Kujala score, Tegner activity score, Lysholm score, ROM, and patellar tilt were assessed postoperatively. Failure was defined by a postoperative patellar dislocation, surgical revision or any complication. Paired t-test and two-way repeated measure ANOVA followed by multiple comparison using Bonferroni test was carried out for statistical analysis, and values of p < 0.05 was considered significant differences.

Results

Among 69 patients (72 knees) who underwent MPFL reconstruction, 60 patients 62 knees (86.9%, 22 males and 38 females) were able to follow-up [mean 3.1 (2 to 5) years]. There were 41 patients (43 knees) in the SQ group and 19 patients (19 knees) in the ST group. There was no difference in preoperative TT-TG distance and sulcus angle. Postoperatively, there was no significant difference in Tegner activity score, but the SQ group showed significantly high score in Lysholm score (ST group: 88.7 ± 12.5 points, SQ group: 95.9 ± 5.9 points; p < 0.01) and Kujala score (ST group: 91.8 ± 4.1 points, SQ group: 94.9 ± 5.1 points; p < 0.01). ROM improved postoperatively in both groups, but there was no significance between the two groups. The tilting angle (preoperative; ST group: 24.8 ± 12.0 degrees, SQ group: 20.2 ± 8.3 degrees) improved significantly (postoperatively; ST group: 10.9 ± 4.8 degrees, SQ group: 11.5 ± 4.5 degrees) (p < 0.01). There were two failures (10.5%) in the ST group with two patellar fractures and one postoperative patellar dislocation requiring additional surgery.

Discussion

Both groups had good short-term results, but postoperative Lysholm score and Kujala score were higher in the SQ group. Postoperative improvement in tilting angle reveals that both grafts contribute to restoring MPFL function. However, concerning failures that occurred in the ST group, SQ autograft may be safe and considerable for MPFLR.