Dual tunnel medial patellofemoral ligament reconstruction for patients with patellar dislocation using a semitendinosus tendon autograft
Introduction
Patellar dislocation occurs by trauma in patients with various combinations of predisposing factors such as general joint laxity, abnormal Q angle, morphological abnormality of the patella or femoral trochlea, patella alta [1]. However, recent anatomical and biomechanical studies have revealed that insufficiency of the medial patellofemoral ligament (MPFL), the major stabilizer of lateral patellar translation, is one of the most important factors predisposing to this disorder [2], [3], [4], [5], [6]. In fact, several studies reported that in acute cases disrupted MPFLs were frequently found and in recurrent cases slackened or non-existent MPFLs were commonly observed [7], [8]. Regarding treatment for patellar dislocation, Arendt et al. concluded that an excellent outcome can be expected by anatomical repair or reconstruction of the key structure: MPFL, for stabilization of the joints [9]. Therefore, anatomical reconstruction of the MPFL is a very appropriate treatment for patellar dislocation. Excellent clinical results have been reported following reconstruction of the MPFL using an artificial ligament or an autogenous tendon graft [10], [11], [12], [13], [14]. However, these procedures have the following potential problems: (1) A single drill hole technique is not suitable to mimic the morphological feature of the MPFL, as it is not a single cord-like structure but one with a wider fan-like insertion to 2/3 of the medial patellar margin [4], [15]; (2) A larger transverse drill hole, into which a thick graft is introduced, may potentially cause patellar fracture due to attenuation of the patella caused by existing soft tissue in the bone [16], [17]; (3) The repair site is likely to be less strong compared to a pull-out fixation when the graft is sutured to the soft tissue around the patella or fixed by suture anchors[10], [13], [17], [18]. Therefore, the purpose of this article was to describe the short-term clinical results of the dual tunnel MPFL reconstruction with pull-out fixation at 45° of knee flexion contriving by the senior author (KS) to overcome the above-mentioned problems.
Section snippets
Patients
Among 30 patients with patellar dislocation who visited our institution between July 2003 and November 2007, six patients with first time dislocation without fracture were conservatively treated, three received MPFL reattachment to the patella due to a peel-off lesion of the medial patellar margin [19], and the remaining 21 patients underwent MPFL reconstruction due to recurrent dislocation or first time dislocation accompanied by osteochondral fracture (Table 1). As one of these patients was
Results
No patient experienced re-dislocation of the patella or patellar fracture. The average postoperative Kujala score was 96 ± 5 (84–100). Ten patients felt slight and occasional pain; four, slight difficulty in jumping; three, pain during repeated squatting; three, slight pain from the start when running; two, pain after more than 2-km running; two, slight atrophy of the thigh; two, pain after exercise upon prolonged sitting with the knee flexed; one, unable to run; one, occasional abnormal painful
Discussion
Previously, Gomes and Nomura et al. reported excellent clinical results using artificial ligament in MPFL reconstruction for patients with patellar dislocation [11], [12]. In addition, several authors reported an outstanding clinical outcome in MPFL reconstruction using an autogenous hamstring tendon graft [10], [12], [13], [14], [16]. In this series all the patients had a high Kujala score and Crosby–Insall grading while none experienced either re-dislocation or patellar fracture, suggesting
Conclusion
The dual tunnel MPFL reconstruction provides favorable results in patient satisfaction and functional outcome.
Conflict of interest statement
No author or related institution has received any financial benefit from research in this study.
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