Why compromise the patella? Five-year follow-up results of medial patellofemoral ligament reconstruction with soft tissue patellar fixation

Sebastian P Boelch,Thomas Barthel,Maximilian Rudert,Stephan Reppenhagen,Anna Gurok,Manuel Weißenberger,Fabian Gilbert

doi:10.1007/s00264-020-04922-1

Sebastian P Boelch, Thomas Barthel + Show 5 more

Open Access

https://doi.org/10.1007/s00264-020-04922-1

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Abstract

PurposeThis study investigates the redislocation rate and functional outcome at a minimum follow-up of five years after medial patellofemoral ligament (MPFL) reconstruction with soft tissue patellar fixation for patella instability.MethodsPatients were retrospectively identified and knees were evaluated for trochlea dysplasia according to Dejour, for presence of patella alta and for presence of cartilage lesion at surgery. At a minimum follow-up of five years, information about an incident of redislocation was obtained. Kujala, Lysholm, and Tegner questionnaires as well as range of motion were used to measure functional outcome.ResultsEighty-nine knees were included. Follow-up rate for redislocation was 79.8% and for functional outcome 58.4%. After a mean follow-up of 5.8 years, the redislocation rate was 5.6%. There was significant improvement of the Kujala score (68.8 to 88.2, p = 0.000) and of the Lysholm score (71.3 to 88.4, p = 0.000). Range of motion at follow-up was 149.0° (115–165). 77.5% of the knees had patella alta and 52.9% trochlear dysplasia types B, C, or D. Patellar cartilage legions were present in 54.2%. Redislocations occurred in knees with trochlear dysplasia type C in combination with patella alta.ConclusionMPFL reconstruction with soft tissue patellar fixation leads to significant improvement of knee function and low midterm redislocation rate. Patients with high-grade trochlear dysplasia should be considered for additional osseous correction.

Highlights

Lateral patella dislocation occurs in 5.8 to 77.8 of 100,000 patients per year [1, 2]
Lateral patella instability can lead to severe functional impairment of the affected knee and recurrent dislocation increases the risk of patellofemoral osteoarthritis [5, 6]
To trochlea dysplasia (TD), patella alta quantified by the Caton-Deschamps Index (CDI) correlates with the manifestation of patella instability [7]

Summary

Introduction

Lateral patella dislocation occurs in 5.8 to 77.8 of 100,000 patients per year [1, 2]. Lateral patella instability can lead to severe functional impairment of the affected knee and recurrent dislocation increases the risk of patellofemoral osteoarthritis [5, 6]. Dejour et al described trochlea dysplasia (TD) as the pathognomonic feature of patella instability [7]. The biomechanical study by Senavongse and Amis described the complex interaction of the patella stabilizing structures such as the musculus vastus medialis obliquus, the trochlea, and the medial patellofemoral ligament (MPFL) [8]. Increased tuberositas tibiae-tibial groove (TT-TG) distance is another crucial risk factor for patellar instability, which is another means of quantification of patellofemoral alignment [9]

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Discussion

Conclusion