A National Perspective of Patellar Instability in Children and Adolescents in the United States: MPFL Reconstruction Is Three Times Higher Than the Incidence of Isolated Lateral Release

Predicting the Probability of Recurrence Based on Individualized Risk Factors After Primary Lateral Patellar Dislocation Treated Nonoperatively

PURPOSE

To develop a comprehensive and effective personalized scoring system on the basis of demographic and clinical characteristics for predicting recurrence probability in patients with primary lateral patellar dislocation (LPD).

METHODS

Participants included 261 primary patients with LPD with 2-year minimum follow-up from our hospital across 2013 to 2020. Demographic and clinical characteristics were collected retrospectively. The backward stepwise method was performed to identify independent predictors and construct a nomogram to predict the probability of recurrence. The predictive performance was assessed by receiver operating characteristic curves, calibration plots, and decision curve analysis.

RESULTS

After variables selection, 6 independent predictors of recurrence (skeletal maturity, trochlear dysplasia, tibial tuberosity-trochlear groove distance, mechanical axis deviation, Insall-Salvati index, and patellar tilt) were enrolled in our model. Validation of this nomogram in both training and validation cohort revealed powerful predictive ability, with an area under the curve of 0.962 and 0.977, respectively. The nomogram also showed great calibration and good clinical practicability.

CONCLUSIONS

Our study presented a nomogram that incorporates 6 independent risk factors (skeletal maturity, trochlear dysplasia, tibial tuberosity-trochlear groove distance, mechanical axis deviation, Insall-Salvati index, and patellar tilt), which can be conveniently used to accurately predicts the risk of recurrence after primary LPD in individual cases.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic study.

Medial Patellofemoral Ligament Reconstruction Using Gracilis Tendon Graft and "All Suture" Knotless Anchors for Patellar Fixation

Patellar dislocation is a frequent sports-related knee injury. The primary restraint to lateral translation of patella is medial patellofemoral ligament. Several treatments for patella dislocation have been described in the literature. The purpose of this Technical Note is to describe the surgical technique for medial patellofemoral ligament reconstruction using gracilis tendon and 2 knotless soft anchors, avoiding patella tunneling.

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.

Editorial Commentary: Patellofemoral Instability Results in Osteoarthritis, and Nonanatomic Surgery and Surgical Over-constraint May Also Cause Osteoarthritis

When we are looking at the stars, we are in fact looking back in time. This is because it takes years for the light from the stars to reach us. In similar fashion, when we are evaluating data on osteoarthritis after patellofemoral surgery, we need to consider what kind of procedure was performed. Furthermore, it is extremely important to answer the question of whether the patellofemoral instability itself or the surgical procedure is causing the arthritis. Recent evidence suggests that recurrent patellofemoral instability is causing cartilage degeneration and stopping this process via surgical restoration of the anatomy and biomechanics of the patellofemoral joint may significantly reduce the risk of osteoarthritis. Shear loading of the cartilage can be detrimental. An instability event elicits inflammatory markers that are shown to induce arthritis. On the other hand, there is the argument that over-constraint may lead to arthritis owing to an increase in cartilage loading. Another argument is that surgery may not fully restore the patellofemoral anatomy. Appropriate patient selection and continuous evolution of our surgical procedures are key elements toward successful management of patellofemoral instability.

Association of Insurance Status With Treatment Delays for Pediatric and Adolescent Patients Undergoing Surgery for Patellar Instability

Background:

Health care disparities have been highlighted in pediatric sports medicine, but the association between insurance status and delayed care for patients undergoing surgery for patellar instability has not been defined.

Purpose:

To determine whether there is an association between insurance status and delays in care in pediatric and adolescent patients undergoing surgery for patellar instability.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This was a retrospective case series at a safety-net tertiary referral center of pediatric and adolescent patients undergoing surgical treatment for patellar instability. Insurance status was classified as public or private. We calculated the times from injury to clinical evaluation, injury to magnetic resonance imaging (MRI), injury to surgery, clinical evaluation to MRI, and clinical evaluation to surgery. Comparisons were made between insurance groups.

Results:

Included were 78 patients (38 public, 40 private insurance) who underwent surgery for patellar instability. The public insurance group was older (P = .019), with a lower proportion of White patients (15.8% vs 52.5%; P = .0005), higher proportion with Hispanic ethnicity (55.3% vs 15.0%; P = .0001), and higher proportion of Spanish-speaking patients (21.1% vs 2.5%; P = .007). Publicly insured patients had longer times from initial injury to clinical evaluation (466 vs 77 days; P = .002), MRI (466 vs 82 days; P = .003), and surgery (695 vs 153 days; P = .0003), as well as a longer time from clinical evaluation to surgery (226 vs 73 days; P = .002). Multivariable models confirmed insurance status as an independent predictor in each of the identified delays.

Conclusion:

Significant delays were seen for pediatric and adolescent patients with patellar instability and public insurance (approximately 6 times longer to clinical evaluation, more than 5.5 times longer to obtain MRI, and 4.5 times longer to surgery) relative to injured patients with private insurance. Even after adjusting for delays to clinical evaluation, publicly insured patients had a delay from clinic to surgery that was triple that of privately insured patients.

Editorial Commentary: Handling the (Contact) Pressure in Patellofemoral Surgery: The Role of Lateral Retinacular Release

The role of lateral retinacular release for the treatment of patellofemoral pathology has evolved over the years. Although once popularized in the treatment of patellofemoral pain and instability, complications such as iatrogenic medial patellar instability and decreases in lateral patellar stability have limited the indications for performing isolated lateral release. However, there exists a need for more clearly defined parameters and understanding of when and how lateral release should be incorporated with other procedures during patellar stabilization and joint-preservation surgery. Advances in finite element analysis, as well as refining our surgical indications and techniques for concurrent lateral release, will allow us to optimize both joint pressures and stability during the surgical management of patellar instability.

Editorial Commentary: Despite Decades of Research on Patellar Instability, the Isolated Lateral Release Endures

Surgical management of patellar instability has transformed over the last 40 years as our understanding of contributing anatomical factors, particularly medial patellofemoral ligament insufficiency, has matured. The International Patellofemoral Study Group recently concluded with 89% agreement that lateral release should not be done in isolation for patellofemoral instability. And yet, with 11% dissent, controversy remains, and the isolated lateral retinacular release for patellar instability continues to be favored by a subset of surgeons. In my opinion, lateral retinacular release may have a role in the rare situation in which laterally based capsuloligamentous tightness has led to focal patellar compression, but in the setting of patellar instability, lateral release should not be used alone as a solution for patellofemoral instability.