Proximal medial patellar restraints and their surgical reconstruction

Recurrent patellar dislocation: treatments and challenges

Recurrent Patellar Dislocation (RPD) is a common knee sports injury, mainly affecting pediatric and adolescent populations, posing a significant challenge in orthopedic clinical practice. Although a variety of treatments have been reported, and many of them have shown good initial results, there is a lack of long-term follow-up results. Each treatment method has its own unique characteristics and limitations, and there is no standardized and unified treatment plan. This article provides a comprehensive review of current treatments for RPD. We believe that regardless of the surgical method used, patellar dislocation should not occur at 0°-90° of postoperative knee flexion and extension, and the range of motion should not be limited. Our ultimate goal is to restore patellar stability and improve lower limb alignment, thereby restoring knee function as much as possible. In addition, future treatment options for RPD are also discussed. In the future, there should be more in-depth research on the risk factors and pathogenesis that lead to recurrent patellar dislocation, as well as more randomized controlled trials focusing on different treatment methods. A comprehensive understanding of these is crucial for implementing preventive measures and developing targeted treatment strategies. The goal of this narrative review is to offer clinicians a deeper understanding of RPD treatment, enhance clinical decision-making skills, and encourage personalized and efficient management of RPD treatment.

Patellofemoral Instability: Preoperative Considerations and Postoperative Imaging

Patellofemoral instability is common, often affecting young female patients. It contributes to significant morbidity, such as pain and premature osteoarthritis. Patient presentation varies, from acute instability events to chronic/recurrent instability. This article provides a detailed description of the anatomy and biomechanics of the patellofemoral joint and relates it to the pathology of patellofemoral instability. There are well-recognized predisposing anatomical factors, such as trochlear morphology, patella height, excessive lateralization of the tibial tubercle, excessive valgus alignment, and femoral or tibial torsion.Diagnosis of patellofemoral instability requires a thorough clinical history and physical examination, combined with a multimodality imaging approach. Imaging is useful in surgical planning to define the severity of predisposing anatomical factors and to detect postoperative complications. The operative management of patellofemoral instability targets predisposing anatomical factors, such as medial stabilizing ligament reconstruction or repair, tibial tubercle osteotomy, femoral trochleoplasty, coronal plane realignment osteotomy, and torsional osteotomy.

Three different patellar fixation techniques yield similar clinical and radiological outcomes in recurrent patellar dislocation undergoing medial patellofemoral ligament reconstruction

PURPOSE

The purpose of this study was to evaluate and compare the clinical and radiological outcomes of three different patellar fixation techniques on medial patellofemoral ligament reconstruction (MPFLR) in the treatment of patellar dislocation (PD).

METHODS

Between 2015 and 2020, 130 patients with recurrent PD who underwent surgical reconstruction were eligible for this retrospective study: 48 patients were treated with the semi-tunnel bone bridge fixation technique (Group A), 42 patients were treated with the suture anchor fixation technique (Group B) and 40 patients were treated with the transpatellar tunnel fixation technique (Group C). Clinical outcomes included functional outcomes (Kujala, Lysholm and International Knee Documentation Committee scores), activity levels (Tegner activity score and return to sports), physical examinations, patellar re-dislocation rate and complications. Radiological outcomes included patellar congruence angle, patellar tilt angle, lateral patellar translation and lateral patellar angle.

RESULTS

All clinical and radiological outcomes improved significantly in all groups, without any significant difference among these three groups. At the final follow-up, no re-dislocation occurred, and all groups achieved a successful return to sports. However, the semi-tunnel bone bridge and suture anchor fixation techniques showed statistically higher Tegner activity scores (p = 0.004) and shorter time from surgery to return to sports (p = 0.007) than the transpatellar tunnel fixation technique.

CONCLUSION

The three MPFLR patellar fixation techniques achieved favourable and comparable clinical and radiological outcomes in the treatment of PD. Compared with the transpatellar tunnel fixation technique, the semi-tunnel bone bridge and suture anchor fixation techniques may be more effective with higher activity levels.

LEVEL OF EVIDENCE

Level III.

A Comparison of Proximal Patellar Realignment vs. Medial Patellofemoral Ligament Reconstruction: A Review of the Literature

» Patellar instability is challenging to address, and although there are many surgical options, proximal patellar realignment (PPR) and medial patellofemoral ligament (MPFL) reconstruction are both used-recently, the MPFL reconstruction has become more popularized.» Both procedures have demonstrated similar recurrent dislocation rates and rates of arthritic progression.» PPR is a cost-efficient procedure using just suture alone as compared with MPFL reconstruction, which uses different grafts and methods of fixation.» PPR has demonstrated durable results, with a lower overall complication rate, much of which is caused by the MPFL reconstruction having unique complications due to fixation methods.» The PPR is a beneficial procedure and should still be considered when dealing with patellar instability.

Accuracy of femoral tunnel positioning in medial patellofemoral ligament reconstruction: anatomic insertion leads to better clinical outcome

PURPOSE

The medial patello-femoral ligament (MPFL) is considered the primary restraint against patellar dislocation and its reconstruction is indicated in recurrent patellar instability. An anatomical positioning of MPFL femoral insertion is recommended to achieve satisfactory clinical outcomes and prevent osteoarthritis (OA) due to an altered kinematics. The purpose of the study was first to assess the relationship between correct femoral tunnel position and better clinical outcomes and lower patellofemoral osteoarthritis rate. Second, correlation of outcomes with factors potentially affecting the results, such as the type of graft, patellar height and trochlear dysplasia.

METHODS

Fifty-three patients (58 knees) who underwent MPFL reconstruction between 2009 and 2018 by a senior knee surgeon were retrospectively evaluated. Knee radiographs were performed before surgery, 12 months later and at last follow-up to assess trochlear dysplasia, patellar height and patellofemoral OA. The tibial tuberosity-trochlear groove (TT-TG) value was measured on a CT scan. The accuracy of graft positioning was evaluated on sagittal radiographs according to Schöttle et al. Subjective outcomes were collected before surgery, at 12 months and at last follow-up using several validated scores.

RESULTS

Forty-six patients (51 knees) with a mean age of 24.1 ± 7.4 years were included in the study. Mean follow-up was 8.9 ± 2.1 years. A significant improvement in all clinical scores was observed at 12 months and final follow-up. Anatomic Insertion (AI) of reconstructed MPFL was considered optimal in 33 (64.7%) and sub-optimal in 18 (35.3%) patients. Sub-optimal AI resulted in lower Kujala, IKCD and higher VAS score (p < 0.01); moreover, for every 1 mm distance in any direction from the ideal insertion, a decrease of 0.8 [95% CI (-1.4; -0.2)] in Kujala score and 0.8 [95% CI (-1.3; -0.3)] in IKDC was observed. At final follow-up, 8 patients presented patellofemoral OA Iwano grade 3 (15.7%): although that incidence did not correlate to graft positioning, the use the artificial ligament in all these cases appeared to be significant.

CONCLUSION

The present study confirms the importance of an optimal anatomic femoral insertion in MPFL reconstruction, reporting a significant positive correlation between graft positioning and clinical outcome. No significant correlations were found between anatomic insertion and patello-femoral OA development.

LEVEL OF EVIDENCE

IV.

Percutaneous Reconstruction of the Medial Patello-Femoral Ligament Using Dynamic Gracilis Tendon Transfer

BACKGROUND

Many techniques have been described for reconstructing the medial patello-femoral ligament (MPFL), using a variety of transplants and fixation methods to treat patello-femoral dislocation. The main challenge with static transfers is to position the femoral fixation point at the site that best restores MPFL anisometry. The objective of this cadaveric study was to propose a version of the initially described dynamic gracilis transfer technique that can be performed percutaneously.

HYPOTHESIS

Our working hypothesis was that using a minimally invasive approach would provide better cosmesis without altering the biomechanical efficacy of the procedure.

METHODS

20 cadaveric knees were used to evaluate the feasibility and reliability of our percutaneous technique. We analysed femoral pulley location and scar length.

RESULTS

After dissection, the position of the femoral pulley allowed superimposition of the transplant along the trajectory of the native MPFL in all 20 knees. Cumulative scar length was 6.5cm (range, 6-7.5cm).

DISCUSSION

Percutaneous dynamic gracilis transfer is easy to perform, reproducible, and capable of creating a pulley that anatomically replicates the femoral insertion point of the native MPFL.

LEVEL OF EVIDENCE

IV; retrospective study.

Lateral retinacular release combined with MPFL reconstruction for patellofemoral instability: a systematic review

INTRODUCTION

The role of the lateral retinaculum in patellofemoral instability is still debated. Lateral retinacular release (LRR), has been extensively performed in combination with different surgical procedures, including reconstruction of medio-patellofemoral ligament (MPFL). Despite controversial indications, the results from these studies seem promising. The present study conducts a systematic review about current biomechanical and clinical evidence concerning the role of LRR in combination with MPFL reconstruction. We performed a comprehensive literature research, comparing the outcomes of MPFL reconstruction with and without LRR.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. The literature search was performed in August 2020. All articles describing the outcome of isolated MPFL reconstruction alone or in combination with a LRR in patients with recurrent patellofemoral instability were considered for inclusion. Only articles reporting data on patients with a minimum of 12-month follow-up were included. Only articles reporting quantitative data under the outcomes of interest were included.

RESULTS

A total of 63 articles were eligible for this systematic review, including 2131 knees. The mean follow-up was 40.87 ± 24.1 months. All scores of interests improved in favour of the combined group: Kujala + 3.8% (P = 0.01), Lysholm + 4.2% (P = 0.004), Tegner + 0.8 points (P = 0.04), IKDC + 9.8% (P = 0.02). The ROM was comparable between the two groups (P = 0.4). Similarity was found in terms of positivity to the apprehension test (P = 0.05), rate of complications (P = 0.1), re-dislocations (P = 0.8), and revision surgeries (P = 0.1).

CONCLUSION

There is no evidence that adding a lateral release impacts positively on the outcome of MPFL reconstruction.

LEVEL OF EVIDENCE

IV, Systematic review.