Isolated reconstruction of medial patellofemoral ligament with an elastic femoral fixation leads to excellent clinical results

Outcomes of Surgical Interventions for Patellofemoral Instability in the Presence of Trochlear Dysplasia: A Systematic Review and Meta-analysis

BACKGROUND

Patellar instability is frequently encountered by orthopaedic surgeons. One of the major risk factors of this condition is underlying trochlear dysplasia (TD). Recent trends have indicated the use of multiple procedures to correct patellar instability under these conditions. Medial patellofemoral ligament reconstruction (MPFLR) and trochleoplasty (TP) are surgical strategies that have demonstrated successful outcomes. However, it is unclear whether isolated MPFLR suffices for patellar instability in the presence of severe TD. Furthermore, the need for TP or a combined approach, considering its invasiveness and technical demands, to achieve better clinical outcomes and patellofemoral stability remains uncertain.

PURPOSE

To compare the outcomes of 3 surgical interventions for addressing patellar instability due to TD: MPFLR, TP, and combined MPFLR and TP.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

Studies reporting the clinical outcomes of MPFLR, TP, and both in combination, regardless of additional procedures, were identified using the MEDLINE, PubMed, Embase, Scopus, Cochrane Library, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature databases. An important inclusion criterion was that studies should include the mean preoperative and postoperative Kujala scores and any complications. A random-effects model was used for the meta-analysis.

RESULTS

Overall, 30 studies were included: 10 describing the outcomes of TP, 13 describing the outcomes of MPFLR, and 7 describing the outcomes of combined TP and MPFLR. Furthermore, 1457 patients (1571 knees) were evaluated with a mean follow-up of 42.4 ± 32.8 months. No statistically significant differences were found between the 3 methods regarding the mean difference using the Kujala score. However, combined MPFLR and TP had the highest weighted mean difference compared with the other 2 procedures (28.5 points; P < .001). Evidential analysis revealed a robust log-likelihood ratio (S = 3.2) supporting the superiority of the combined procedure when comparing this mean and the weighted grand mean of 23.7. The redislocation rate after patellar stabilization remained minimal, irrespective of the surgical procedure (mean, 0.7%). However, the rate of residual patellar instability was the highest in the TP group (mean, 13.5%).

CONCLUSION

This study found no statistically significant difference between the outcomes of the 3 procedures. However, the combined approach of MPFLR and TP was associated with the most promising clinical outcomes and a low redislocation rate in patients with varying severities of TD.

Combination of the medial patellofemoral ligament reconstruction with the quasi-anatomic technique, tibial tuberosity osteotomy, lateral retinaculum release and mosaicplasty produces satisfactory results for patients with patello-femoral instability. 2-Year follow-up

INTRODUCTION

This study aimed to evaluate the effectiveness and safety of a combined surgical approach for treating complex patellofemoral instability. This approach combines four procedures: medial patellofemoral ligament (MPFL) reconstruction with the quasi-anatomic technique, lateral retinaculum release, anteromedialization and distalization of tibial tuberosity and patellar/femoral mosaicplasty.

MATERIAL AND METHODS

Between August and November 2021, we enrolled 27 patients in the study (21 females, 6 males, average age 28.6 years). All with patella alta, recurrent patellar instability, severe cartilage focal damage, and increased tibial tubercle-trochlear groove distance. All underwent the combined procedure during this period. We assessed their pain and functional scores before surgery and at 6, 12, and 24 months after surgery using standardized scoring systems.

RESULTS

Patients initially reported significant pain and functional limitations. However, at 24 months, their pain scores significantly reduced, averaging 1.5 compared to 8.2 pre-surgery. Similarly, their functional scores substantially improved, with Lysholm, Tegner, Kujala, BPII scores reaching 87.44, 8.44, 90.03, 86.07 compared to 56.4, 3.7, 42.48, 23 pre-surgery, respectively. Importantly, no cases of recurrent instability occurred, and 96.3% of patients reported complete satisfaction.

CONCLUSIONS

This combined surgical approach has a high rate of success for patients with patella alta, recurrent lateral patellar instability, severe focal chondral lesions, and increased TT-TG distance. Moreover, 26 out of 27 patients (96.3%) reported total satisfaction. Therefore, we conclude that although this procedure combination is not simple, it is a safe, reproducible, and alleviates pain at 24 months postoperatively, and significantly improves functional scores.

Patellofemoral Instability Part II: Surgical Treatment

Treatment of patellofemoral instability in skeletally mature patients remains an important area of clinical and research interest. Both nonsurgical and surgical interventions are used to treat the underlying causes. Surgical management is the mainstay of treatment of recurrent PFI that fails nonsurgical treatment, and it is broadly classified into bony and soft-tissue procedures. Proximal bony procedures include femoral trochleoplasty, derotational osteotomies, and coronal alignment correction of the femur. Distal bony procedures include tibial tubercle transfer and derotational (supratubercle and infratubercle) osteotomies. Soft-tissue procedures consist of medial patellofemoral ligament repair or reconstruction and lateral lengthening procedures. This article is the second part of our two-article review on PFI, which focuses on surgical treatment options, their indications, outcomes, and potential complications.

Influence of medial patellofemoral ligament reconstruction on patellar tracking and patellofemoral contact pressures in patella alta

Knee squatting was simulated to characterize the influence of medial patellofemoral ligament (MPFL) reconstruction on patellar tracking and contact pressures for knees with mild patella alta (Caton-Deschamps index = 1.3-1.4). Eight computational models represented knees in the pre-operative condition and following MPFL reconstruction. MPFL reconstruction significantly reduced patellar lateral tracking at low flexion angles based on bisect offset index, significantly decreased the maximum lateral pressure in mid-flexion, and significantly increased the maximum medial pressure in mid-flexion. MPFL reconstruction improves patellar stability for knees with mild patella alta and can reduce the pressure applied to lateral cartilage on the patella.

Stiffness and Instability After MPFL Reconstruction Using a Fluoroscopic Versus Open Technique to Localize the Femoral Attachment Site: A Systematic Review and Meta-analysis

Background

Open and fluoroscopic techniques have been described for localization of the femoral attachment site in medial patellofemoral ligament (MPFL) reconstruction. No study to date has evaluated if one technique is superior to another in terms of complications.

Purpose

To review the literature comparing clinical outcomes of MPFL reconstruction using the fluoroscopic versus open technique to localize the site of femoral graft placement.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic literature review was performed via PubMed, Embase, and CINAHL to identify articles published between the inception of these databases and March 1, 2022, in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. This search yielded 4183 publications for initial review. Studies with at least a 2-year follow-up and complete reporting of patient-reported outcomes, range of motion, recurrent instability, and/or complications (ie, stiffness, infection, persistent pain) were included. We excluded studies of patients with collagen disorders; revision surgeries; surgeries with concomitant procedures; synthetic MPFL reconstruction; MPFL repairs; combined open and radiographic technique; and case series that included <10 patients. A proportional meta-analysis was performed by calculating the pooled estimate of incidence with 95% CIs using a fixed-effects model with double arcsine transformation (Freeman-Tukey) for each type of surgical technique (fluoroscopic or open).

Results

A total of 29 studies met our inclusion criteria, of which 15 studies (566 patients) used the open technique and 14 studies (620 patients) used fluoroscopy. There were no significant differences between the open and fluoroscopic techniques in the incidence of postoperative apprehension (P = .4826), postoperative subjective instability (P = .1095), postoperative objective instability (P = .5583), reoperations (P = .7981), recurrent dislocation (P = .6690), or arthrofibrosis (P = .8118).

Conclusion

Both open and radiographic localization of the femoral graft position in MPFL reconstruction offer similar outcomes and rates of complications.

Allografts for Medial Patellofemoral Ligament (MPFL) Reconstruction in Adolescent Patients with Recurrent Patellofemoral Instability: A Systematic Review

This systematic review updates the currently available evidence on medial patella-femoral ligament (MPFL) reconstruction using allografts. The outcomes were measured with patient-reported outcome measures (PROMs), redislocation and complication rates. This study was performed according to the 2020 PRISMA guidelines using the PubMed, Scopus, Web of Science databases, accessed in February 2023. Studies examining the clinical outcomes of MPFL reconstruction with allografts in adolescents and children with recurrent patellofemoral instability (PFI) were included. Data from three trials, including 113 surgical procedures in 121 children, were retrieved. 40% (48/121) of the included patients were girls. The mean age of the patients was 14.7 ± 0.8 years, and the mean follow-up length was 38.1 ± 16.5 months. With MPFL allograft reconstruction, the Kujala score improved by 14.7% (p < 0.0001) and the IKDC by 38.8% (p < 0.0001). The rate of dislocations was 5% (6 of 121), reoperation for instability was 11% (13 of 121), and subluxation was 2% (1 of 47). Conclusion: These results encourage the use of allografts for MPFL reconstruction in adolescent patients with recurrent patellofemoral instability. Though patellofemoral instability is common in clinical practice, the current literature lacks clinical evidence on allograft MPFL reconstruction. Additional high-quality investigations are required to properly establish the long-term advantages of allograft MPFL and its complication rate.

Complication Rates After Medial Patellofemoral Ligament Reconstruction Range From 0% to 32% With 0% to 11% Recurrent Instability: A Systematic Review

PURPOSE

To review the incidence of complications following primary medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability.

METHODS

A literature search was conducted by querying PubMed and Scopus databases from database inception through August 2022 according to the 2020 Preferred Reporting Items for Systematic Review and Meta-analysis guidelines using the terms "Medial Patellofemoral Ligament," "MPFL," "reconstruction," "patellar," and "instability." Inclusion criteria included studies reporting complications following primary MPFL reconstruction for recurrent patellar instability. Exclusion criteria consisted of studies reporting on patients undergoing concurrent osteotomy procedures, revision reconstruction, and biomechanical or anatomic studies. The incidence of specific complications was aggregated from the included studies.

RESULTS

Twenty-eight studies, consisting of 1,478 patients (n = 1521 knees), with a mean age of 23.3 years (mean range, 19-34.3 years) were identified. The overall incidence of complications ranged from 0% to 32.3% of knees. Failure ranged from 0% to 10.7% of knees, whereas patellar fractures occurred in 0% to 8.3% of knees, primarily in patients treated with full-length transverse tunnel or 2-tunnel techniques. All patellar fractures occurred in patients with patellar tunnels ranging from 4.5 to 6.0 mm in diameter. The incidence of postoperative knee stiffness/range of motion deficit ranged from 0% to 20%. Persistent anterior knee pain, ranged from 0% to 32.3%.

CONCLUSIONS

Complications following primary MPFL reconstruction ranged from 0% to 32.3% of knees, primarily consisting of residual anterior knee pain. Failure ranged from 0% to 10.7% of knees, whereas patellar fractures were reported in 0% to 8.3% of knees. Fractures primarily occurred with a full-length transverse tunnel or 2-tunnel techniques, whereas all fractures occurred with patellar tunnels ranging from 4.5 mm to 6.0 mm in diameter.

LEVEL OF EVIDENCE

IV; Systematic Review of Level I-IV studies.

Protocols of rehabilitation and return to sport, and clinical outcomes after medial patellofemoral ligament reconstruction with and without tibial tuberosity osteotomy: a systematic review

PURPOSE

No consensus exists on rehabilitation programmes after medial patellofemoral ligament reconstruction (MPFLR) with or without tibial tuberosity osteotomy (TTO). This systematic review examined the content and timeline of rehabilitation (weightbearing, range of motion [ROM] and exercise therapy) and return to sport (RTS), as well as patient-reported outcomes after MPFLR with or without TTO.

METHODS

The PubMed, Cochrane Library, Web of Sciences, CINAHL and SPORTDiscus databases were searched from inception to December 2021. Studies that reported postoperative rehabilitation programmes and patient-reported outcomes for patients aged ≥ 18 years who underwent MPFLR with or without concomitant TTO were included.

RESULTS

Eighty-five studies were included, 57 of which were case series and only one randomised controlled trial on rehabilitation programmes. Non-weightbearing was set within one week post-operatively in approximately 80% of weightbearing programmes for MPFLR without and with TTO. Joint immobilisation was set within one week post-operatively in 65.3% and 93.8% of programmes for MPFLR without and with TTO, respectively. Weightbearing and ROM (≤ 90°) restriction were within three weeks post-operatively for > 50% of the programmes. Quadriceps strengthening was the most cited exercise therapy (33 programmes), most often initiated within two weeks post-operatively. However, few other exercise programmes were cited (only nine programmes). RTS was mostly noted at six months post-operatively (35 programmes). The weighted mean Kujala score was 87.4 points.

CONCLUSION

Regardless of TTO addition to MPFLR, most studies restricted weightbearing and ROM only in the early post-operative period, with seemingly favourable clinical results. Limited information was available on post-operative exercise therapy.

Comparable outcome for autografts and allografts in primary medial patellofemoral ligament reconstruction for patellofemoral instability: systematic review and meta-analysis

PURPOSE

This study updates the current evidence on the role of allografts versus autografts for medial patellofemoral ligament (MPFL) reconstruction in patients with patellofemoral instability.

METHODS

The study was performed according to the PRISMA guidelines. In March 2021, a literature search in the main online databases was performed. Studies reporting quantitative data concerning primary MPFL reconstruction using an allograft were considered for inclusion. The Coleman Methodology Score was used to assess the methodological quality of the selected articles.

RESULTS

Data from 12 studies (474 procedures) were retrieved. The mean follow-up was 42.2 (15-78.5) months. The mean age was 21.1 ± 6.2 years. 64.9% (285 of 439) of patients were female. At the last follow-up, the Tegner (p < 0.0001), Kujala (p = 0.002) and the Lysholm (p < 0.0001) scores were minimally greater in the autografts. The similarity was found in the rate of persistent instability sensation and revision. The allograft group evidenced a lower rate of re-dislocations (p = 0.003).

CONCLUSION

Allografts may represent a feasible alternative to traditional autograft for MPFL reconstruction in selected patients with patellofemoral instability. Allograft tendons yielded similar PROMs, rates of persistent instability, and revision. Allograft reconstructions tended to have modestly lower re-dislocation rates.

LEVEL OF EVIDENCE

IV.

Hardware-free MPFL reconstruction in patients with recurrent patellofemoral instability is safe and effective

PURPOSE

This systematic review evaluated the clinical outcomes of hardware-free MPFL reconstruction techniques in patients with recurrent patellofemoral instability, focusing on patient-reported outcome measures (PROMs), redislocation rate, and complications. The hypothesis was that hardware-free MPFL reconstruction in patients with recurrent patellofemoral instability is safe and effective.

METHODS

This systematic review was conducted following the PRISMA guidelines. PubMed, Scopus, and Virtual Health Library databases were accessed in October 2021. All the clinical studies investigating the efficacy and feasibility of hardware-free MPFL reconstruction were screened for inclusion. Only studies with a minimum 24-month follow-up were considered eligible. Kujala Anterior Knee Pain Scale improvement and redislocation rate after surgical treatment were evaluated as primary outcomes. The rate of postoperative complications was evaluated as a secondary outcome. The quality of the methodological assessment was assessed using the Modified Coleman Methodology Score.

RESULTS

Eight studies were included in the present systematic review. The quality of the methodological assessment was moderate. Short- to long-term improvement of Kujala score was observed in all included studies. Mean score improvement ranged from + 13.2/100 to + 54/100, with mean postoperative scores ranging from 82/100 to 94/100. Patellar redislocation was observed in 8.33% (8 of 96) patients.

CONCLUSION

Hardware-free MPFL reconstruction with or without associated soft-tissue or bony realignment procedures provided reliable clinical improvements and was associated with a low rate of redislocation in patients with recurrent patellofemoral instability. Advantages such as safety, femoral physis preservation, and comparable complication profiles with implant-based techniques endorse its implementation. Orthopedic surgeons in cost-sensitive environments may also benefit their patients with lower costs, no need for implants, lack of implant-related complications, or surgery for implant removal.

LEVEL OF EVIDENCE

Level IV.

Are Patellofemoral Ligaments and Retinacula Distinct Structures of the Knee Joint? An Anatomic, Histological and Magnetic Resonance Imaging Study

There is disagreement regarding the description of the patellofemoral ligaments (PFLs), considered by some authors as capsular thickening and by others as independent ligaments. It was hypothesised that the PFLs and retinacula are structures with different histological features. The aim of this study was to describe the stabilising structures of the patella in detail and to determine if the PFLs and retinacula are different and separable structures from a macroscopic, microscopic and imaging viewpoint. An anatomical study was performed on eight knees from five cadavers (mean age, 56.2 years; range, 35–63 years), and a histological study was conducted on specimens from nine patients having a mean age of 65 years (range 35–84 years) who had undergone surgical knee procedures. The imaging study was based on 100 MRIs (96 patients). The mean age was 46 years (range 16–88), and the study analysed the capsular-ligamentous structures. In the medial compartment, the layers and structures were as follows: superficial layer, medial retinaculum; intermediate layer, Medial Collateral Ligament (MCL), Posterior Oblique Ligament (POL) and Medial Patellofemoral Ligament (MPFL); deep layer, deep part of the MCL and joint capsule. In the lateral compartment, the layers and structures were the following: superficial layer, lateral retinaculum; intermediate layer, Lateral Collateral Ligament (LCL) and Lateral Patellofemoral Ligament (LPFL); deep layer, joint capsule. All of the knees examined presented a clearly distinguishable MPFL and LPFL separable from the capsular layer. Histological study: there was a higher density of nerve fibres in retinacula compared to ligaments (p = 0.0034) and a higher content of elastic fibres in retinacula (p < 0.0005). In imaging, there was no difference between medial and lateral retinaculum thickness (p > 0.05). In conclusion, both the lateral and medial compartment can be described using the three-layer scheme. PFLs and retinacula are separate structures both macroscopically and according to imaging analysis. The retinacula respond to their specific function with a higher nerve fibre content and higher number of elastic fibres compared to the ligaments.

Medial patellofemoral ligament reconstruction with and without trochleoplasty for patients with patella instability-correlation of trochlear dysplasia and patient outcome, classification and outcome measure in the past decade-a systematic review

PURPOSE

The primary aim of the study is to compare the patient outcome in medial patellofemoral ligament reconstruction (MPFLR) or MPFLR concurrent with trochleoplasty (MPFLR + TP) and correlate it with the degree of trochlear dysplasia (TD). The secondary aim is to review TD classification, outcome measure, chronological and geographical trend of such studies in the past decade.

METHODS

A systemic review of the literature in the past decade on studies of patients with patella instability and underwent either a MPFLR or MPFLR + TP. The degree of TD with the patient outcome was correlated and compared between the 2 groups. The TD classification, outcome measures, chronological and geographical trends of these studies were documented.

RESULTS

There is no statistical difference in the overall improvement in the compared outcome scores between the 2 groups. However, the MPFLR studies reported a total of 16 re-dislocation in contrast to none in the MPFLR + TP studies. The 24 selected studies in the current review utilized different TD classification as well as outcome measures. A more homogeneous subgroup of 12 studies utilized Dejour classification as well as Kujala score that enabled comparison and showed no significant difference in outcome. The highest number of MPFLR publications was in 2019 and was from North and South Americas, Asia and Europe. The MPFLR + TP studies were from Europe during 2013 to 2017.

CONCLUSION

Though there is an overall improvement in post-operative outcomes scores with no statistical significance between MPFLR and MPFLR + TP, the documented re-dislocations in the MPFLR studies suggested an undetermined zone where the choice of procedure could result in a different outcome. The current review did not show correlation between the degree of TD with the patient outcome to provide a clear indication for either procedure according to the degree of TD. The diverse TD classifications and varied outcome measures indicated the need for standardization and consistency in documentation to guide the treating clinician in the choice of procedure. MPFLR was more commonly performed and studied than MPFLR + TP in the past decade.