Anatomic physeal-sparing technique for medial patellofemoral ligament reconstruction in skeletally immature patients with ligamentous laxity

Medial Patellofemoral Ligament Reconstruction in Skeletally Immature Patients: A Systematic Review of Outcomes by Fixation Technique

Background

Various medial patellofemoral ligament (MPFL) reconstruction techniques have been developed to minimize risks to the physis in skeletally immature patients.

Purpose

To examine outcomes of MPFL reconstruction (MPFLR) based on fixation technique in skeletally immature patients.

Study Design

Systematic review; Level of evidence, 4.

Methods

PubMed, Scopus, Ovid, Cochrane Library, and CINAHL databases were searched for the literature on outcomes of MPFLR in the pediatric population, utilizing various anatomic and nonanatomic techniques. Primary outcomes were postoperative redislocation rates, return-to-sports (RTS) rates, and patient-reported outcomes (PROs). Moreover, outcomes involving sequela of growth plate disturbance were collected.

Results

The final analysis included 17 studies-2 using sling-based techniques, 3 using surface-based techniques, 5 using soft tissue realignments, and 7 utilizing transosseous femoral fixations. Higher rates of postoperative redislocation were found in the sling-based (14.8%) and distal soft tissue realignment using semitendinosus tenodesis (38%) techniques, while lower rates were noted with surface-based (1.3%) and transosseous (3.4%) techniques. For PROs, there were large amounts of heterogeneity among studies, but all reported postoperative improvements, with more positive PROs generally seen in anatomic reconstructions. The RTS rate was 100% for surface-based techniques, 79.4% for distal soft tissue realignments, 79.5% for soft tissue realignment techniques, and 83.2% for transosseous techniques. No negative outcomes as a sequela of growth plate disturbance were reported.

Conclusion

Nonanatomic techniques-such as sling-based and distal soft tissue realignment techniques-have higher rates of redislocation and lower RTS rates in skeletally immature patients undergoing MPFLR. Surface-based and transosseous tunnel-based techniques were shown to have lower redislocation and higher RTS rates.

Clinical Relevance

This review provides insight into the most appropriate surgical management of patellar instability in patients with open growth plates.

A Cadaveric Study of the Sagittal Patellar Insertion of the Medial Patellofemoral Ligament in Children: Implications for Reconstruction

BACKGROUND

Patellofemoral instability is a common problem, and medial patellofemoral ligament (MPFL) reconstruction is a standard treatment approach for recurrent instability. The accurate restoration of anatomy in MPFL reconstruction is essential. While coronal-plane anatomy of the MPFL patellar insertion has been previously reported, sagittal-plane anatomy has not been widely studied.

PURPOSE

To evaluate the sagittal patellar insertion of the MPFL in pediatric specimens to guide future anatomic reconstruction.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 11 pediatric cadaveric knee specimens were dissected. The patella and sagittal MPFL insertion were evaluated. The maximal anterior-posterior patellar width, distance from the posterior patella to the posterior MPFL insertion, distance from the medial patellar articular cartilage edge to the MPFL insertion, maximal MPFL thickness, and distance from the anterior MPFL insertion to the anterior patella were measured. The proportion of patellar coverage by the sagittal MPFL insertion footprint was calculated.

RESULTS

The pediatric knee specimens had a mean age of 9.3 ± 1.4 years (range, 6-11 years). The mean maximal transverse patellar width was 19.0 ± 2.7 mm (range, 13.7-22.7 mm). The mean posterior patella-to-posterior MPFL distance was 10.5 ± 1.6 mm (range, 7.7-12.6 mm). The mean patellar articular cartilage edge-to-MPFL distance was 2.3 ± 0.6 mm (range, 1.5-3.5 mm). The mean maximal MPFL thickness was 4.0 ± 0.9 mm (range, 2.6-5.5 mm). The mean anterior MPFL-to-anterior patella distance was 4.4 ± 1.1 mm (range, 2.6-5.8 mm). The sagittal MPFL insertion footprint spanned a mean of 21.0% (range, 16.1%-29.7%) of the medial patella.

CONCLUSION

This study, utilizing skeletally immature cadaveric specimens, demonstrated that the sagittal MPFL insertion consistently resided in the anterior third of the patella, averaging 21% of the total sagittal patellar width. Additionally, the distance from the MPFL insertion to the medial patellar articular cartilage edge showed minimal variation, representing a consistent intraoperative landmark for MPFL graft placement.

CLINICAL RELEVANCE

This research characterized MPFL insertion anatomy on the medial patella in the sagittal plane. This knowledge provides a clear target area for anatomic graft placement during MPFL reconstruction.

Physeal-Sparing Soft Tissue Realignment in Pediatric Patellofemoral Instability Patients: A Review of Treatment Options and Outcomes

Patellofemoral instability is a common condition in children, with an annual incidence of approximately 50 cases per 100,000 children. Instability of the patella involves a number of structures, such as the medial patellofemoral ligament and the vastus medialis obliquus, which can be used for patellar realignment in soft tissue, physeal-sparing procedures. In this rapid review, we aim to review the surgical interventions, post-operative outcomes, and associated surgical complications of global soft tissue procedures in the management of patellofemoral instability. A search of the Medline database was conducted to identify studies evaluating the treatment and outcomes of global treatment of pediatric patellofemoral instability. The included studies analyzed the surgical management of patellofemoral instability in pediatric patients, utilizing soft tissue global procedures and reported functional outcomes, return to sport or play, and post-operative complications. A total of eight studies were included, comprising a cohort of 270 pediatric and adolescent patients and 334 knees. The average patient age was 10.6 years, with 60.4% (163/270) patients being female, and the mean follow-up duration was 58.4 months. Of the eight studies, two examined the three-in-one procedure, three examined the four-in-one procedure, one examined a combination of medial and lateral release, and two examined the Galeazzi procedure. This review underscores the variety of global physeal-sparing surgical procedures available for treating patellofemoral instability. While outcomes are generally favorable, with high rates of return to sport, recurrent residual instability and recurrent dislocation remain significant challenges, with residual instability affecting nearly half of patients. Future research should focus on exploring long-term outcomes, optimizing patient selection, and identifying the causes of recurrent instability to further enhance patient outcomes and reduce complication rates.

Outcomes of an All-Soft Tissue Fixation Technique for Reconstruction of the Medial Patellofemoral Complex Using Double-Bundle Quadriceps Tendon Autograft for Recurrent Patellar Dislocation in Skeletally Immature Patients

Background

Patellar fracture, femoral physis injury, and recurrent instability are concerning complications in medial patellofemoral ligament (MPFL) reconstruction (MPFLR) techniques for recurrent patellar dislocation in children and adolescents.

Purpose

To evaluate the outcomes of an anatomic all-soft tissue fixation technique for reconstruction of the medial patellofemoral complex (MPFC) using a double-bundle quadriceps tendon (QT) autograft for recurrent patellar dislocation in skeletally immature patients.

Study Design

Case series; Level of evidence, 4.

Methods

This retrospective study involved 24 skeletally immature patients (24 knees; 16 women and 8 men; age range, 9.5-15 years) with recurrent patellar dislocation who underwent MPFC reconstruction using a double-bundle QT autograft between September 2018 and January 2021. Only soft tissue suture fixation was used on the femoral and patellar sides of the 2 bundles of the QT. Radiographs, computed tomography, and magnetic resonance imaging were used to evaluate physeal status, lower limb alignment, patellar height and tilt, trochlear morphology, tibial tubercle-trochlear groove distance, and any associated knee pathology. Functional outcomes were assessed with the Kujala score, the visual analog scale (VAS) for pain, and the grading system of Insall et al.22.

Results

The mean follow-up time was 40 ± 9.6 months (range, 28-56 months). At the final follow-up, the Kujala and VAS pain scores showed a significant improvement versus preoperative scores (P < .001), and the passive lateral patellar glide showed a significant reduction (P < .001). All patients had negative apprehension and J signs. Of the 24 patients, 23 regained full range of motion, while 1 patient had a knee flexion deficit. The patellar tilt angle improved significantly at the final follow-up (P < .001). There was no patellar fracture, femoral physis injury, or recurrence of patellar dislocation. According to the grading system of Insall et al, the results were excellent in 15 knees (62.5%), good in 8 knees (33.3%), fair in 1 knee (4.2%), and no knees showed poor results.

Conclusion

Reconstruction of the MPFC using a double-bundle QT autograft with an all-soft tissue fixation technique was an effective method for treating patellar instability in skeletally immature patients.

Outcomes of surgical treatment of patellar instability in children with Down syndrome

BACKGROUND

patellar instability is a relatively frequent musculoskeletal disorder in children with Down syndrome (DS). However, such a condition has seldom been studied in the literature, even less its surgical treatment. Different techniques have been offered for this condition; the evidence for surgical options is scarce and primarily based on case reports or case series with few patients and heterogeneous techniques. Given this background, we aimed to evaluate the outcomes of a uniform kind of surgical procedure for such a condition that combined lateral soft tissue release, medial patellofemoral ligament (MPFL) reconstruction (using a partial-thickness quadriceps tendon autograft), the Roux-Goldthwait procedure, and V-Y quadricepsplasty (if needed).

MATERIALS AND METHODS

This retrospective study involved 11 skeletally immature patients (12 knees; 9 males and 2 females), 5.5 to 14.1 years of age, with DS who had patellofemoral instability (PFI) and were managed by this technique between October 2018 and March 2020. Preoperative radiography, CT scan, and MRI were performed to evaluate the physis status, lower limb alignment, patellar height, trochlear morphology, and any associated knee pathology. A functional knee assessment was done by using the Kujala score and the modified Lysholm score.

RESULTS

The mean time of follow-up (± SD) was 47.7 ± 5.8 months (range: 39-56). Pre-operatively, the Kujala score (± SD) was 52.6 ± 14.3 (range: (31-74), and at final follow-up, it was 92.2 ± 4.4 (range: (88-98), showing a significant improvement (P < 0.001). The preoperative modified Lysholm score (± SD) was 54.3 ± 8.1 (range: 39-62), and at final follow-up it was 92.4 ± 5.3 (range: 82-96), showing a significant improvement (P < 0.001). All patients had a stable patella without a recurrence of instability and regained full ROM. There was no incidence of a patellar fracture or femoral physis injury.

CONCLUSIONS

Our proposed technique of combined soft tissue procedures, including lateral soft tissue release, MPFL reconstruction (using a partial-thickness quadriceps tendon autograft), the Roux-Goldthwait procedure, and V-Y quadricepsplasty, was an effective method for treating patellar instability in children with DS while avoiding physeal injury and patellar fracture. Functional scores and radiological outcomes were improved.

LEVEL OF EVIDENCE

IV; retrospective case series.

Medial Patellofemoral Ligament Reconstruction Using Pedicled Quadriceps Tendon Autograft Yields Similar Clinical and Patient-Reported Outcomes but Less Donor-Site Morbidity Compared With Gracilis Tendon Autograft

PURPOSE

To compare clinical and patient-reported outcome measures (PROMs) in patients with recurrent patellar dislocation after medial patellofemoral ligament (MPFL) reconstruction using either a gracilis tendon (GT) or quadriceps tendon autograft (QT).

METHODS

All MPFL reconstruction performed between 2017 and 2019 were reviewed retrospectively. Only patients with isolated MPFL reconstruction, without any major patellofemoral risk factors and a minimum follow-up of 24 months, were included in the study. Patients were matched with respect to sex, age, and body mass index. All patients were evaluated clinically and using PROMs.

RESULTS

A total of 64 patients with an average follow up of 28.7 ± 7.5 months were included in this study. The mean Kujala score (GT: 84.8 ± 12.9, QT: 88.9 ± 10.1), Lysholm score (GT: 89.4 ± 10.2, QT: 88.4 ± 5.0), and visual analog scale score for pain (GT: 1.9 ± 1.8, QT: 1.1 ± 1.3) did not significantly differ between both groups. Tegner activity level was significantly greater (P = .027) in the QT group (5.5 ± 1.9) compared with the GT group (4.6 ± 1.8), but within the minimal clinically important differences. Occasional patellar instability events, but no recurrent dislocation, were reported in 12.5% in the GT group and 6.3% in the QT group (P = .39). Of all patients, 90.6% in the QT and 68.8% in the HT group exceeded the PASS for the Kujala score (P = .06). Significantly more patients (59.4%) treated with GT reported donor-site morbidity in the form of sensitivity deficit at the lower leg compared with those treated with QT (3.1%, P = .001).

CONCLUSIONS

GT and QT MPFL reconstruction have comparable PROMs and patellar redislocation rates 2 years' postoperatively. Significantly more patients treated with GT reported lower-leg sensitivity deficit compared with those treated with QT.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

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.

Evaluation of the Optimal Femoral Fixation Site for Medial Patellofemoral Ligament Reconstruction in the Skeletally Immature Patient

The aim of this study was to assess which femoral fixation site, distal to the physis, most closely emulates the native medial patellofemoral ligament (nMPFL) length relationship in the pediatric knee. Lateral knee radiographs were taken incrementally, from 0° to 120° of flexion. The femoral origin of the nMPFL and 3 other MPFL femoral fixation sites distal to the physis were identified (P1, 1 cm distal to physis along the posterior femoral cortex; P2, 2 cm distal to physis along the posterior femoral cortex; P3, 1 cm distal and 1 cm anterior). Virtual MPFL lengths were measured from all sites. Measurement reliability was assessed using intraclass correlation coefficients. Primary comparison between simulated MPFL length at native and femoral fixation sites was made using a repeated measures analysis of variance at 30° flexion. Bivariate Pearson correlation was used to assess the relationship between fixation sites and nMPFL through the range of motion (alpha=0.05). The intra-class correlation coefficient for intraobserver reliability of MPFL length measurement was excellent. Analysis of variance showed virtual MPFL lengths from proposed femoral fixation sites at 30° were significantly different from nMPFL length (P<.01). The P1 MPFL had the least difference in means compared with nMPFL (-2.6±1.8 mm). Correlational analysis showed that P1 MPFL had the closest relationship with nMPFL compared with other femoral fixation sites (R=0.91, P<.01). The P1 MPFL had the length change most comparable to that of nMPFL (23.9±3.1 mm vs 13.3±2.85 mm) compared with the other simulated MPFLs. Femoral graft fixation site 1 cm distal to the physis in the lateral view along the posterior femoral cortex closely represents the length relationship of the nMPFL. [Orthopedics. 2023;46(2):108-113.].

Return to sports and short-term follow-up of 101 cases of medial patellofemoral ligament reconstruction using gracilis tendon autograft in children and adolescents

INTRODUCTION

An acute patellofemoral dislocation is the most common acute knee injury in children. Recent studies suggest up to 40% of immature patients may develop recurrent instability. MPFL reconstruction has become a mainstay for the treatment of patellofemoral instability. Aim of the recent study is to show our experiences of MPFL reconstruction in patellar instability in immature patients using a gracilis autograft in respect to return to sport, growth plate disorders and short-term results.

MATERIALS AND METHODS

A total of 101 patients (50 females, 51 males) were included in this retrospective study. Mean age at time of operation was 14.8 ± 1.6 years. Primary outcome measures included patient satisfaction, Kujala score, recurrent instability, return to normal activity, return to sports, clinical leg axis and complications. Mann-Whitney U test was used for statistical analysis and alpha was set at p < 0.05 to declare significance.

RESULTS

At a mean follow-up of 32.0 ± 12.1 months 90/101 patients could be followed-up. 84% of all patients were satisfied or very satisfied with the result at latest follow-up. 86.6% of all patients were able to return to sports, 2.3% had a relevant deviation of the clinical leg axis, but symmetrical. In sum complication rate was 2.9%. Redislocation rate was 0.9% (1/101). Kujala Score improved significantly from 47.1 preoperatively to 85.3 postoperatively (p < 0.01).

CONCLUSION

Anatomic MPFL reconstruction using gracilis tendon allograft tissue is a safe procedure in children and adolescents with low risk of recurrent instability.

Medial Patellofemoral Ligament Reconstruction in the Pediatric Population: Skeletal Immaturity Does Not Affect Functional Outcomes but Demonstrates Increased Rate of Subsequent Knee Injury

Purpose

To evaluate short- to mid-term-outcomes, including instability rates, following medial patellofemoral ligament (MPFL) reconstruction in skeletally immature versus mature pediatric patients.

Methods

Patients younger than age 18 with recurrent patellar instability who underwent primary allograft MPFL reconstruction by a single surgeon from 2013 to 2019 were identified. Skeletally immature patients underwent all-epiphyseal drilling and mature patients underwent metaphyseal drilling at the Schöttle’s point. Patients 1 year from surgery were contacted to complete questionnaires, which included the International Knee Documentation Committee score. Further data included chart and imaging review. Significance was determined by P < .05.

Results

Of 118 eligible patients, 88 completed questionnaires. There were 67 skeletally mature and 21 skeletally immature patients. The mature group was older (15 vs 13 years, P < .001), predominantly female (67 vs 43%, P = .046), and heavier (24.7 vs 18.9, P < .001). Trochlear dysplasia (P = .594), concomitant procedures (P = .336), graft choice (P = .274), and follow-up length (P = .107) did not differ, although mature patients more often underwent suture tape augmentation (68 vs 13%, P < .001). Immature patients had greater rates of ipsilateral injury (35 vs 16%, P = .043); redislocation rate did not differ (9 vs 3%, P = .225). Mature patients were more likely to respond “definitely yes or probably yes” when asked if they would undergo the same care if needed (96 vs 76%, P = .007). At minimum 2-year follow-up, subsequent ipsilateral injury rates did not differ, although willingness to undergo the same care remained significant (95 vs 69%, P = .010). In a multivariable elimination logistic regression model, skeletal maturity was the only variable associated with subsequent ipsilateral injury (P = .049).

Conclusions

Pediatric patients undergoing MPFL reconstruction have good and comparable outcomes regardless of skeletal maturity. However, younger age and lack of tape augmentation in skeletally immature patients may predispose them to subsequent injury.

Level of Evidence

III, case-control study.

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.

Polyethylene Suture Augmentation of the Medial Patellofemoral Ligament in Skeletally Immature Patients with Recurrent Patella Dislocation

In skeletally immature patients with recurrent patella dislocation that needs operation, how to increase the medial stability of the patella effectively without disturbance of the epiphysial plate is of concern. Through evaluation of multiple techniques that designed to avoid injury to the epiphysial plate, we found that medial patellofemoral ligament augmentation with high-strength nonabsorbable sutures is feasible and effective. Thus, we would like to describe this technique, whose critical point is the correct location and creation of the 2 femoral tunnels. We consider the introduction of the current technique will provide reasonable choices when operation is needed in this special group of patients.

The Superficial "Swing-Down" Quadriceps Tendon Autograft Is a Viable Option for Medial Patellofemoral Ligament Reconstruction: A Systematic Review

PURPOSE

The purpose of this systematic review is to ascertain the reported clinical outcomes and complication profiles of medial patellofemoral ligament (MPFL) reconstruction performed using a superficial "swing-down" quadriceps tendon autograft.

METHODS

Three databases (PubMed, EMBASE, and MEDLINE) were searched from January 1, 2000, to April 06, 2020. Keywords used in the search included: "medial patellofemoral ligament" and "reconstruction". After screening based on inclusion and exclusion criteria, patient demographics, graft type, outcomes, and complications were extracted. Methodological Index for Non-Randomized Studies criteria were used to assess the quality of each included study.

RESULTS

Eleven studies were included, comprising data from 226 patients with mean follow up ranging from 12 to 38 months. All reconstructions used a superficial "swing-down" quadriceps tendon autograft fixed at 20-30 degrees of knee flexion where reported. Eight of eleven studies reported significant improvement in patient reported outcomes such as Kujala score, Lysholm score, and Tegner score. The mean preoperative Kujala score ranged from 35.8 to 82.1 (167 patients), while the mean postoperative Kujala score ranged from 88.4 to 94.8 (197 patients). The mean of the preoperative Lysholm score ranged from 43.3 to 79.3 (77 patients), while the mean of the postoperative Lysholm score ranged from 81.9 to 90.9 (99 patients). The I² statistic for Lysholm and Kujala scores was 94% and 97%, respectively. Across data reported on 194 patients, there was no incidence of patellar redislocation, patellar fracture, or graft site morbidity.

CONCLUSION

The quadriceps tendon produced improved clinical outcomes with low rates of recurrent postoperative patellar dislocation. These data suggest that the quadriceps tendon remains a suitable alternative for MPFL reconstruction and should remain part of the arsenal of knee ligament surgeons.

LEVEL OF EVIDENCE

Systematic review of Level III and IV studies.

Pedicled Strip of Quadriceps Tendon Graft for Primary Medial Patellofemoral Ligament Reconstruction in Recurrent Patellofemoral Instability: A Systematic Review

PURPOSE

A systematic review of the literature was conducted to ascertain advantages and limitations, update current evidences, and investigate the role of a pedicled quadriceps tendon autograft for primary medio-patellofemoral ligament (MPFL) reconstruction in patients with recurrent patellofemoral instability.

METHODS

The present systematic review was performed according to the PRISMA guidelines. The literature search was conducted in September 2020. All the clinical studies investigating the role of a pedicled strip of quadriceps tendon autograft for primary MPFL reconstruction in patients with recurrent patellofemoral instability were considered for inclusion. Studies investigating the role of MPFL reconstruction combined with additional surgical procedures except for lateral retinacular release were excluded. The methodological quality assessment was performed through the modified Coleman Methodology score.

RESULTS

Data from 9 articles (191 procedures) were retrieved. The mean follow-up was 12 to 38 months. The mean age of the patients was 11.5 to 25.2 years. One hundred twenty of 191 patients were female. All clinical scores showed significant improvement following the procedures. The Kujala score improved of 32.52% points (P < 0.0001), the Lysholm score of 23.74% (P = 0.006), the Tegner scale improved of 8.6% (P = 0.02). Concerning complications, after surgery the apprehension test was positive in 5 of 166 patients, and persistent joint instability was found in 5 of 149 patients. No patient experienced any re-dislocations or underwent reoperations.

CONCLUSIONS

The use of pedicled strip of quadriceps tendon as graft for MPFL reconstruction is a suitable choice in patients with recurrent patellar instability. Although frequently associated with a lateral release, it is unclear whether the latter is necessary for the success of the technique. Appropriately powered randomized controlled trials comparing this graft source to the others commonly used are necessary to at least ascertain the noninferiority of this graft to the others.

LEVEL OF EVIDENCE

IV, Systematic review of Level III-IV studies.

Conservative versus repair of medial patellofemoral ligament for the treatment of patients with acute primary patellar dislocations: A systematic review and meta-analysis

PURPOSE

The aim of this study was to perform a meta-analysis to compare the effects of repair of medial patellofemoral ligament (MPFL) and conservative treatment in patients with acute primary patellar dislocation (PPD).

METHOD

The databases we used to search the studies included MEDILINE, EMBASE, and Cochrane registry of controlled clinical trials. Five randomized controlled studies comparing the effects of MPFL repair versus conservative treatment with 300 acute PPD patients were included in the present meta-analysis. Primary outcome was redislocation rate and secondary outcomes included Kujala score, percentage of excellent or good subjective opinion, Tegner activity score, and knee injury and osteoarthritis outcome score (KOOS; pain, symptoms, and activities of daily living).

RESULTS

The outcome of the Kujala score was statistically significant between the two treatments and indicated that MPFL repair had a higher Kujala score than conservative treatment in patients with acute PPD. There was no significant difference between the two treatments regarding the redislocation rate (p = 0.32), percentage of excellent or good subjective opinion (p = 0.15), Tegner activity score (p = 0.24), and KOOS (p > 0.05).

CONCLUSIONS

Based on the available data, MPFL repair did not reduce the risk of redislocation nor did it produce any significantly better outcome based on the clinical manifestations, including anterior knee pain and knee activities. Only the Kujala score was improved by MPFL repair compared with conservative treatment.

Recurrent patellofemoral instability rates after MPFL reconstruction techniques are in the range of instability rates after other soft tissue realignment techniques

PURPOSE

Recurrent patellofemoral instability is a common knee injury in skeletally immature patients. Many surgical techniques have been described in the literature, all with different success rates. Purpose of this study was to perform a systematic review and meta-analysis of the available literature to assess recurrent patellofemoral instability rates after surgical treatment using MPFL reconstruction techniques and other soft tissue realignment techniques in skeletally immature patients.

METHODS

PubMed, Embase, Web of Science, and The Cochrane Library were searched to identify all original articles concerning the surgical treatment for patellofemoral instability in skeletally immature patients and that reported post-operative recurrent patellofemoral instability rates. Subsequently a risk of bias assessment was conducted and a meta-analysis was performed on reported post-operative recurrent patellofemoral instability rates after MPFL reconstruction techniques and other soft tissue realignment techniques.

RESULTS

Of the 21 eligible studies (448 knees in 389 patients), 10 studies reported on MPFL reconstruction techniques using different grafts and fixation techniques and 11 reported on other soft tissue realignment procedures. In total, 62 of the 448 (13.8%) treated knees showed recurrent patellofemoral instability during follow-up. The overall pooled recurrent patellofemoral instability rate was estimated to be 0.08 (95% CI 0.02-0.16). For MPFL reconstruction techniques, the pooled recurrent patellofemoral instability rate was estimated to be 0.02 (95% CI 0.00-0.09). For the other soft tissue realignment techniques, the pooled rate was estimated to be 0.15 (95% CI 0.04-0.31). No statistically significant difference in recurrent patellofemoral instability rates between MPFL reconstruction techniques and other soft tissue realignment techniques were found (n.s.). There was a large variation in treatment effects over different settings, including what effect is to be expected in future patients.

CONCLUSION

This systematic review and meta-analysis found that recurrent patellofemoral instability rates after MPFL reconstruction techniques are in the range of instability rates after other soft tissue realignment techniques. The clinical relevance of this study is that it provides clinicians with the best currently available evidence on recurrent patellofemoral instability rates after surgical treatment for patellofemoral instability in skeletally immature patients.

LEVEL OF EVIDENCE

IV.

Medial Patellofemoral Ligament Reconstruction and Nonanatomic Stabilization Techniques in Skeletally Immature Patients

Patellar instability is a common cause of knee disability in children and adolescent, with a high recurrence rate. When conservative treatment fails, surgical options should be considered. The femoral insertion of the medial patellofemoral ligament (MPFL) is in close proximity to the distal femoral growth plate and precautions should be taken to avoid injuries to the physis. Anatomical features of the MPFL complex, with focus on the relationship between femoral MPFL attachment and femoral physis, are discussed together with surgical tips to avoid injuries to the growth plates. The aim of this article is to review the recent literature regarding MPFL reconstruction and other stabilization techniques for patellofemoral instability in skeletally immature patients, focusing on the different surgical options available. These can be classified as anatomical versus nonanatomical, proximal versus distal realignments, or based on the graft used: free graft and pedicled graft (quadriceps, patellar tendon, hamstring, and adductor magnus).

Medial Patellofemoral Ligament Reconstruction in Skeletally Immature Patients: A Systematic Review and Meta-analysis

BACKGROUND

Given the proximity of the medial patellofemoral ligament (MPFL) femoral insertion to the distal femoral physis in skeletally immature patients, multiple techniques for femoral graft fixation have been described.

PURPOSE

To systematically review the literature and evaluate outcomes and complications following MPFL reconstruction in skeletally immature patients.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive literature search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines through use of the PubMed, Embase, and Cochrane Central databases. All original, English-language studies reporting outcomes or complications following MPFL reconstruction in skeletally immature patients were included. Skeletally mature patients were excluded. Data regarding demographics, surgical technique, graft type, outcomes, and complications were recorded. Study quality was assessed by use of the modified Coleman methodology score. Statistical analysis was performed through use of chi-square and weighted mean pooled cohort statistics, where appropriate, with significance set at P < .05.

RESULTS

7 studies that entailed 132 MPFL reconstructions (126 patients) met the inclusion criteria. Females comprised 57.9% of the cohort (73 females), and the mean age was 13.2 years (range, 6-17 years). Mean postoperative follow-up was 4.8 years (range, 1.4-10 years). All of the grafts used were autograft, with gracilis tendon (n = 80; 60.6%) being the most common. Methods of femoral fixation included interference screw (n = 52; 39.4%), suture anchor (n = 51; 38.6%), and soft tissue pulley around the medial collateral ligament or adductor tendon (n = 29; 21.9%). Pooled Kujala scores improved from 59.1 to 84.6 after MPFL reconstruction. The total reported complication rate was 25.0% (n = 33) and included 5 redislocations (3.8%) and 15 subluxation events (11.4%). No cases of premature physeal closure were noted, and there were 3 reports of donor site pain (2.3%). Neither autograft choice (P > .804) nor method of femoral fixation (P > .416) influenced recurrent instability or overall complication rates.

CONCLUSION

These findings suggest that MPFL reconstruction in skeletally immature patients is a viable treatment option, with significant improvement in patient-reported outcomes and redislocation event rates of less than 5% at nearly 5-year follow-up. Further high-quality research is needed to determine optimal graft options and surgical technique while considering recurrent instability, donor site morbidity, and potential injury to the adjacent physis.

Modified adductor sling technique: A surgical therapy for patellar instability in skeletally immature patients

BACKGROUND

Due to open femoral physis the therapy of patellar instability in skeletally immature patients is challenging. We developed a modified surgical technique of the 'Adductor-Sling-Approach' by Sillanpää. The purpose of this study was to evaluate the clinical outcome of the operative technique and to analyse the reasons for failure.

METHODS

Thirty 'modified adductor sling' reconstructions in 28 patients were included in the study. From 2010 to 2016 modified adductor sling reconstruction was performed by looping the gracilis or semitendinosus tendon around the adductor magnus tendon and attaching it at the medial facet of the patella. Clinical outcome was retrospectively evaluated at a mean follow up of 25.6months (range 12-43). The evaluation also included subjective International Knee Documentation Committee (IKDC), Lysholm Score, Kujala Score and Tegner Activity Score.

RESULTS

The average age at the time of operation was 15.10years (range 11-17). Eighty-seven percent of the patients, who underwent the modified adductor sling technique, gained a stable patella and excellent results in postoperative scores. Recurrent dislocation occurred in four of 30 cases (13%). Analysis showed that possible reasons for failure of the tendon graft could be maltracking of the patella due to patella alta, trochlear dysplasia or an elevated tibial tuberosity to trochlear groove distance.

CONCLUSION

The modified adductor sling technique for MPFL reconstruction in children and adolescents showed elevated redislocation rates. Only in absence of additional patellofemoral maltracking, caused by elevated tibial tubercle to trochlear groove distance (>15mm), patella alta or especially severe trochlear dysplasia, the modified adductor sling technique could be recommended.

Acquired femoral flexion deformity due to physeal injury during medial patellofemoral ligament reconstruction

BACKGROUND

Reconstruction of the medial patellofemoral ligament (MPFL) is the most frequent surgical procedure performed in patients with patellar instability. Recently, concerns regarding physeal injury during femoral tunnel placement for anatomical MPFL reconstruction in children have been discussed.

METHODS

This is the first case to report partial posterior physeal growth arrest and subsequent flexion deformity of the distal femur after MPFL reconstruction in a skeletally immature patient. The cause and treatment are discussed.

RESULTS

Postoperative knee extension deficit and recurrent patellar instability were successfully treated with revision surgery including, distal femoral extension osteotomy, medialization of the tibial tuberosity, trochleoplasty and MPFL graft tensioning.

CONCLUSION

This case highlights that care should be taken during femoral tunnel placement for anatomic graft fixation to avoid physeal injuries in skeletally immature patients.

[Patellofemoral instability in trisomy 21: MPFL-Reconstruction as a single procedure]

BACKGROUND

Patellar instability is a common orthopaedic condition which is often seen in younger individuals. Biomechanical studies have shown that the medial patellofemoral ligament (MPFL) is the most important soft tissue that restrains lateral subluxation of the patella in the beginning of flexion of the knee joint.

METHODS

MPFL reconstruction is an effective procedure to treat recurrent patellar dislocation. Double-bundle and single-bundle procedures have been described. If double-bundle reconstruction is not possible, there are good postoperative outcomes with single-bundle procedure as well.

DISCUSSION

This is the first report of MPFL reconstruction as a single procedure to treat patellar instability in patients with down syndrome.