Abstract
Objectives:
Medial patellofemoral ligament reconstruction (MPFLR) is widely acknowledged as a therapeutic approach for patella instability. While hamstring autografts are widely used in MPFLR, there are concerns regarding complications associated with the patella bone tunnel and fixation hardware, such as the endobutton. As an alternative, the superficial quadriceps (SQ) tendon has also been used presently. To date, few studies have evaluated the comparison of clinical outcomes between the grafts. The purpose of the present study is 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 between 2017 and 2020 and were able to follow up for >2 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° 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 at one year postoperatively. Failure was defined by a postoperative patellar dislocation, surgical revision for recurrent patellar instability or any complication. Paired t test and 2-way repeated measure analysis of variance followed by multiple comparison using the Bonferroni test was carried out for statistical analysis, and statistical differences were considered significant for values of p < 0.05.
Results:
Among 70 MPFL reconstructions, 65 patients (92.9%, 24 males and 41 females) were able to follow-up. The mean follow-up period was 3.1 years (2 to 5 years). There were 22 patients in the ST group and 43 patients in the SQ group. There was no difference in preoperative TT-TG distance (ST group: 14.1 mm ± 4.6 mm, SQ group: 16.2 mm ± 3.1 mm) and sulcus angle (ST group: 143.1° ± 12.4°, SQ group: 139.6° ± 8.9°). Postoperatively, there was no significant difference in Tegner activity score (ST group: 5.5 points ± 2.2 points, SQ group: 5.8 points ± 2.2 points), but the SQ group showed significantly high score in Lysholm score (ST group: 88.7 points ± 12.5 points, SQ group: 95.9 points ± 5.9 points; p < 0.01) and Kujala score (ST group: 91.8 points ± 4.1 points, SQ group: 94.9 points ± 5.1 points; p < 0.01). ROM improved postoperatively, but there was no significance between the 2 groups. The Tilting angle (preoperative; ST group: 24.8° ± 12.0°, SQ group: 20.2° ± 8.3°) improved significantly (postoperatively; ST group: 10.9° ± 4.8°, SQ group: 11.5 ± 4.5°) (p < 0.01). There were 3 failures (13.6%) in the ST group with 2 patellar fractures and 1 postoperative patellar dislocation requiring additional surgery.
Conclusions:
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.
