Abstract
The medial patellofemoral ligament (MPFL) has been known as the primary soft-tissue restraint to lateral patellar translation. More recent anatomic studies have identified additional fibers that extend to the quadriceps tendon (medial quadriceps tendon–femoral ligament [MQTFL]), leading to the use of the term “medial patellofemoral complex” (MPFC) to describe the broad and variable attachment of this complex on the patella and quadriceps tendon. Whereas many techniques and outcomes of traditional MPFL reconstruction have been described, fewer reports exist on anatomic MPFC reconstruction to recreate both bundles of this complex. To date, the specific biomechanical roles of, and indications for, reconstruction of the MPFL versus MQTFL fibers have not been defined. One primary benefit of MQTFL reconstruction has been to avoid the risk of patella fracture, which is not obviated in the setting of concurrent patellar fixation when reconstructing both components of the MPFC. The risks and benefits comparing fixation on the patella, quadriceps tendon, or both with anatomic double-bundle reconstruction remain to be determined. Additional studies are needed to understand the differences between reconstructing the proximal and distal fibers of the MPFC with regard to graft length changes and femoral attachment sites, in order to optimally recreate the function of each graft bundle in the surgical treatment of patellar instability.
The medial patellofemoral ligament (MPFL) has been known as the primary soft-tissue restraint to lateral patellar translation. More recent anatomic studies have identified additional fibers that extend to the quadriceps tendon (medial quadriceps tendon–femoral ligament [MQTFL]), leading to the use of the term “medial patellofemoral complex” (MPFC) to describe the broad and variable attachment of this complex on the patella and quadriceps tendon.
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Although many techniques and outcomes of traditional MPFL reconstruction have been described, fewer reports exist on anatomic MPFC reconstruction to recreate both bundles of this complex.In their study “Arthroscopic Anatomical Double-Bundle Medial Patellofemoral Complex Reconstruction Improves Clinical Outcomes in Treating Recurrent Patellar Instability Despite Trochlear Dysplasia, Elevated TT-TG Distance and Patellar Alta,” Shi, Hu, Xu, Meng, Chen, Yang, Wang, Ao, and Liu
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report on double-bundle MPFC reconstruction using semitendinosus autograft in 42 knees in 29 patients at 47.3 ± 20.2 months of follow-up. In the authors’ reconstruction technique, one limb of the graft was placed on the patella between the proximal margin and upper third while the other limb was placed on the quadriceps tendon at the superior patellar margin. Both grafts were fixed to a single tunnel on the medial femur.Shi et al.
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report good results with the described technique. In 95.2% of the patients, improvement in the International Knee Documentation Committee score exceeded the minimal clinically important difference, with 96.9% returning to sports and 90% returning at or above their preoperative level of activity. No dislocations or subluxations were reported in this series, with no postoperative complications except for knee pain (28%) and sporadic giving way (10%). In this group, 73.8% of knees had Dejour type B, C, or D trochlear dysplasia; 42.9% had coronal malalignment as indicated by a tibial tubercle–trochlear groove distance greater than 20 mm; and 54.8% had patella alta with an Insall-Salvati index greater than 1.2.Although no direct comparison was made between outcomes of knees with anatomic risk factors and outcomes of those without them, Shi et al.
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present promising results after double-bundle MPFC reconstruction performed as an isolated procedure, even in the setting of anatomic risk factors for which concurrent procedures such as osteotomy are typically performed. Future studies delineating the impact of each anatomic risk factor, as well as the additive role of multiple risk factors, on outcomes after isolated ligament reconstruction will help us identify which patients are optimal candidates for this surgical approach.Additionally, Shi et al.
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describe a new technique to re-create the structures that comprise the MPFC, incorporating both the patellar and quadriceps tendon attachments. To date, the specific biomechanical roles of, and indications for, reconstruction of the MPFL versus MQTFL fibers have not been defined. One primary benefit of MQTFL reconstruction is that the risk of patellar fracture is avoided, which is not obviated in the setting of concurrent patellar fixation with this technique. Further studies are needed to identify the risks and benefits of fixation on the patella, quadriceps tendon, or both, during patellar stabilization surgery. As we explore the role of anatomic double-bundle reconstruction techniques, understanding the differences between the proximal and distal fibers of the MPFC based on graft length changes and femoral attachment sites will shed light on approaches to optimize the isometric function of each graft bundle.6
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Shi et al.
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describe a novel technique to recreate the anatomy of the MPFC, incorporating fixation on both the patella and the quadriceps tendon using a double-bundle technique. Furthermore, they report promising results with isolated MPFC reconstruction, even in the setting of anatomic risk factors. As our understanding of the anatomy and biomechanics of the MPFC evolves, future studies are needed to identify the roles of graft fixation on the patella and/or the quadriceps tendon as a single- or double-bundle construct, as well as to understand the indications for and limitations of each in the treatment of patellar instability.Supplementary Data
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References
- Variability in the patellar attachment of the medial patellofemoral ligament.Arthroscopy. 2016; 32: 1667-1670
- The anatomic midpoint of the attachment of the medial patellofemoral complex.J Bone Joint Surg Am. 2016; 98: 1199-1205
- Anatomic study of the attachment of the medial patellofemoral ligament and its characteristic relationships to the vastus intermedius.Knee Surg Sports Traumatol Arthrosc. 2013; 21: 305-310
- Medial quadriceps tendon-femoral ligament: Surgical anatomy and reconstruction technique to prevent patella instability.Arthrosc Tech. 2013; 2: e125-e128
- Arthroscopic anatomical double-bundle medial patellofemoral complex reconstruction improves clinical outcomes in treating recurrent patellar instability despite trochlear dysplasia, elevated TT-TG distance and patellar alta.Arthroscopy. 2023; 39: 102-111
- Femoral origin anatomy of the medial patellofemoral complex: Implications for reconstruction.Arthroscopy. 2020; 36: 3010-3015
- Radiographic landmarks for the femoral attachment of the medial patellofemoral complex: A cadaveric study.Arthroscopy. 2022; 38: 2504-2510
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The author reports no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
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