Abstract
The role of medial patellofemoral ligament (MPFL) repair versus reconstruction in the treatment of patellar instability continues to undergo debate. Repair of the ligament can be technically less demanding with fewer risks of morbidity, whereas reconstruction carries concerns of graft malpositioning or over-tensioning as well as the risk of patellar fracture. Studies directly comparing the 2 procedures in the setting of recurrent patellar instability have consisted of small series or low levels of evidence that inevitably include patients with concurrent morphologic risk factors such as tuberosity malalignment or patella alta, which are known factors that can influence the biomechanical behavior of the MPFL. Heterogeneity in patient-related risk factors and surgical techniques continues to pose limitations in allowing for direct comparisons between procedures. For the treatment of recurrent patellar instability in the setting of no (or concurrently addressed) morphologic abnormalities, MPFL reconstruction has become a common procedure and generally preferred approach. The superior outcomes associated with reconstruction over repair, however, should be qualified with the fact that attention to the critical details of the technique, including graft position and tension, is paramount to success when performing this procedure.
The medial patellofemoral ligament (MPFL) is known as the primary static restraint to lateral translation of the patella,
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yet the role of its repair versus reconstruction in the treatment of patellar instability continues to undergo debate. Repair of the ligament can be technically less demanding with a lower risk of morbidity, whereas reconstruction carries concerns of graft malpositioning or over-tensioning as well as the risk of patellar fracture. Prior studies have shown mixed outcomes after MPFL repair with recurrence rates ranging from 17% to 46% at 2 to 4 years’ follow-up.2
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Studies directly comparing repair versus reconstruction have consisted of small series or low levels of evidence that inevitably included patients with concurrent morphologic risk factors such as tuberosity malalignment or patella alta, which are known factors that can influence the biomechanical behavior of the MPFL.5
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In their study “Recurrent Patellar Dislocations Without Untreated Predisposing Factors: Medial Patellofemoral Ligament Reconstruction Versus Other Medial Soft Tissue Surgical Techniques—A Meta-analysis,” Previtali, Roumenov, Pagliazzi, Filardo, Zaffagnini, and Candrian
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aimed to address this issue by identifying studies that allowed for analysis of the comparative outcomes. They included 319 knees from 6 studies and reported no significant differences in rates of recurrent dislocation or minor complications at 2 to 5 years’ follow-up. However, they reported significant differences in Kujala and Lysholm scores favoring reconstruction in both short- and long-term follow-up. They further reported on subgroup analyses isolating reconstruction techniques and selection of predisposing factors, with all functional outcomes with the exception of the Tegner score significantly favoring MPFL reconstruction over repair.The presence of numerous permutations of morphologic risk factors in patients with patellar instability has made it difficult to isolate the clinical benefits of one procedure over another, even in high-volume centers. The careful compilation and analysis of comparable data by Previtali et al.
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have shed light on the differences between the 2 procedures in the setting of relatively isolated MPFL insufficiency. Although great effort was taken to eliminate confounding factors in this study, it should be noted that 3 of the 6 studies included in this meta-analysis excluded subjects with these anatomic risk factors12
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whereas the other 3 studies included some patients with concurrent tibial tuberosity osteotomy with medialization and/or distalization procedures to address malalignment or patella alta.15
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Although the authors report that a subanalysis comparing patients with and without osteotomy confirmed the results, it is unknown whether corrected morphologic abnormalities and the native absence of such constitute the same risk profile in these patients, especially given the interrelatedness between anatomic risk factors in this condition.18
Heterogeneity within surgical techniques continues to be another limiting factor in allowing for direct comparison between procedures. In the current study, the MPFL repair group included plication, augmentation, imbrication, medial soft tissue plasty, and reefing.
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The MPFL reconstruction group included variations in graft type and configurations. Although the use of concurrent osteotomy was algorithmically incorporated, such patients were not included in all studies. Despite these assumptions, however, the authors have produced one of the largest studies to answer the important question of whether suture repair or reconstruction with a graft is superior in restoring soft-tissue restraints during the treatment of recurrent patellar instability.One of the important lessons that this study additionally highlights is that redislocation rates after surgical treatment serve only as an extreme measure that may not adequately capture the “success” of a procedure such as patellar stabilization. Magnussen et al.
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have reported on this regarding function after primary patellar dislocation with conservative management, emphasizing that functional scores provide “a more complete picture of the patient’s outcome” than dislocation rates alone. In analyzing authors’ reports, as well as our own patient outcomes, paying particular attention to this measure is an important consideration in truly understanding the roles these procedures play in the course of treatment of this condition.In summary, for the treatment of recurrent patellar instability in the setting of no (or concurrently addressed) morphologic abnormalities, MPFL reconstruction has become a common procedure, and the current study supports this approach.
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The superior outcomes associated with reconstruction over repair, however, should be qualified with the fact that attention to the critical details of the technique, including graft position and tension, is paramount to success when performing this procedure. Current investigations aim to better understand the respective procedures in the setting of acute first-time dislocations, and the thresholds for which concurrent procedures are needed in the setting of bony abnormalities continue to be defined. As we continue to develop and improve on existing surgical techniques, collaboratively working toward a standardized method of reporting our algorithms and findings can help our progress toward optimizing outcomes in the treatment of patellar instability.Supplementary Data
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Article info
Publication history
Accepted:
February 21,
2020
Received:
February 17,
2020
Footnotes
See related article on page 1725
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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© 2020 by the Arthroscopy Association of North America
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- Recurrent Patellar Dislocations Without Untreated Predisposing Factors: Medial Patellofemoral Ligament Reconstruction Versus Other Medial Soft-Tissue Surgical Techniques—A Meta-analysisArthroscopyVol. 36Issue 6
- PreviewTo provide a direct comparison between medial patellofemoral ligament (MPFL) reconstruction and the other medial patellofemoral soft-tissue surgeries in the restoration of the medial patellar restraint after lateral patellar dislocations in the absence of untreated predisposing factors such as high grade trochlear dysplasia, knee malalignment, patella alta or high tibial tubercle-trochlear groove distance.
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