Patellofemoral chondral status after medial patellofemoral ligament reconstruction using second-look arthroscopy in patients with recurrent patellar dislocation

Particulated Juvenile Articular Cartilage Allograft Transplantation for Patellofemoral Defects Shows Favorable Return-to-Sport Rates and Patient-Reported Outcomes

PURPOSE

To report return-to-sport rates, postoperative patient-reported outcomes (PROs), complication rates, and reoperation rates of a cohort of patients undergoing particulated juvenile articular cartilage (PJAC) allograft transplantation for patellofemoral articular cartilage defects.

METHODS

We performed a single-institution retrospective review of all patients with patellofemoral articular cartilage defects who received PJAC allograft transplantation from 2014 to 2022. Baseline demographic characteristics and surgical data, including concomitant surgical procedures, were collected. Clinical outcomes recorded included return-to-sport rates, complications, reoperations, and the following PRO scores: Kujala knee score, Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference score, and PROMIS Physical Function score.

RESULTS

Forty-one knees with a mean age of 23.4 ± 9.7 years and mean follow-up period of 30.3 months (range, 12-107 months) were included. The mean postoperative PROMIS Pain Interference, PROMIS Physical Function, and Kujala knee scores were 47.4 ± 7.7, 52.2 ± 10.8, and 81.7 ± 16.1, respectively, reflecting low residual anterior knee pain and a return to normal function. For patients playing organized sports at the high school and collegiate levels, the overall return-to-sport rate was 100% (17 of 17). During follow-up, complications developed in 12 knees (29.3%), the most common of which was anterior-based knee pain, and 6 knees (14.6%) required a total of 8 reoperations, which occurred from 6 to 32 months postoperatively.

CONCLUSIONS

The 100% return-to-sport rate and satisfactory PRO scores in our study suggest that PJAC allograft transplantation can effectively address patellofemoral cartilage defects in many patients. The complication and reoperation rates of 29.3% and 14.6%, respectively, are consistent with the challenging and heterogeneous etiology and treatment of patellofemoral articular defects.

LEVEL OF EVIDENCE

Level IV, case series.

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.

Isolated medial patellofemoral reconstruction outcomes: A systematic review and meta-analysis

BACKGROUND

Treatment of patellar instability remains up for debate, and a combination of tibial tubercle osteotomy and medial patellofemoral ligament reconstruction (MPFLr) of the medial patellofemoral ligament (MPFL) has become the mainstay treatment for recurrent lateral patellar dislocation. Due to limited small studies, there remains a variety of surgical techniques still being practiced. The use of MPFL reconstruction, in isolation, has demonstrated promise.

PURPOSE

The purpose of this systematic review and meta-analysis is to investigate if isolated medial patellofemoral ligament reconstruction (iMPFLr) can safely and efficaciously restore knee stability and to present the patient demographics, surgical techniques, graft choices, clinical outcomes, and complications after iMPFLr for recurrent patellar dislocation (RPD).

METHODS

A review of the current literature according to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, yielded 299 abstracts. Twenty-seven articles met the inclusion/exclusion criteria accounting for 1200 patients. Data was pooled and analyzed focusing on patient demographics, graft type used, Kujala, International Knee Documentation Committee (IKDC), Lysholm, Tegner, and complications.

RESULTS

Across all studies the weighted mean age was found to be an average of 24.5 years, BMI was 24.9 kg/m2, follow-up was 47.3 months, as 67% were female, TT-TG distance was 15.3 mm, and Caton Deschamps index 1.11. The pooled effect size difference of pre versus post assessment of Kujala was -2.8, IKDC was -4.5, Lysholm was -6.4, and Tegner was -0.74. The pooled complication rate was found to be 8% across all included studies. A subgroup analysis was also performed, specifically looking at how single bundle, double bundle, gracilis, semitendinosus and knee angle during fixation effect outcome data.

CONCLUSION

This systematic review and meta-analysis demonstrates that isolated MPFL reconstruction is a safe and effective treatment for recurrent patellar dislocations. Given the efficacy of isolated MPFL reconstruction, future investigations should aim to uncover the exact TT-TG distance, trochlear dysplasia, and patella alta grade for selecting patients to undergo this procedure. Furthermore, more primary research needs to be conducted on this topic due to the overall lack of published data from randomized controlled studies and no broad standardization of outcome measurements.

LEVEL OF EVIDENCE

(4) Systematic Review and Meta-Analysis.

Combined quadriceps medial patellofemoral ligament reconstruction and osteochondral fixation offers good patient-reported outcomes and low rates of recurrent instability for osteochondral defects secondary to acute patella dislocation

PURPOSE

Chondral injuries secondary to traumatic patella dislocation are common, and a subgroup of these are significant defects with fragments amenable to fixation. There is a paucity of published evidence assessing patients managed with combined acute patellofemoral stabilisation and osteochondral fixation. The purpose of this study is to report the outcomes of patients with osteochondral injuries secondary to acute traumatic patella dislocation treated with combined early fragment fixation and MPFL reconstruction using a quadriceps tendon turndown technique which has distinct advantages for this cohort, including preventing chondral overloading and non-violation of the patella bone.

METHODS

Patients who underwent combined quadriceps tendon MPFL reconstruction and osteochondral fixation were included. Patient demographics, defect characteristics, complications and reoperations were evaluated. Patients were assessed with Lysholm, Kujala, KOOS-PF scores and satisfaction scale at follow up. Pre-operative MRI was assessed for presence of radiological risk factors for patella dislocation and post-operative MRI was used to assess cartilage quality with MOCART 2.0 score.

RESULTS

A total of 19 patients (63.2% female) were included. The mean age was 17.4 ± 4.8 years and patients were followed up at a mean 15.8 ± 5.1 months post-surgery. The mean defect size was 2.4 cm2 ± 1.3 cm2, with the most common defect location being the patella (13/19; 68.4%) followed by the lateral femoral condyle (5/19; 26.3%). At final follow up, the overall mean Lysholm, Kujala, and KOOS-PF scores were 84.9 ± 11.1, 89.7 ± 5.8 and 80.6 ± 13.6, respectively. Seventeen patients (89.5%) were satisfied with their outcome. The mean MOCART 2.0 score at final follow-up was 72.5. One patient required medial capsular plication with removal of a loose chondral body and microfracture and 3 knees required minor reoperations.

CONCLUSION

Combined acute osteochondral fragment fixation and MPFL reconstruction using a quadriceps tendon graft offers good radiological and patient-reported outcomes with high satisfaction and low rates of recurrent patella dislocation. To our knowledge, this is currently the largest series of its kind in the literature and the results of this study provide a rationale for a combined approach using a quadriceps tendon graft for this cohort.

LEVEL OF EVIDENCE

Level IV.

Clinical and Second-look Arthroscopic Results for Derotational Distal Femoral Osteotomy With Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation With Increased Femoral Anteversion: A Series of 102 Cases With a Minimum Clinical Follow-up of 2 Years

BACKGROUND

Derotational distal femoral osteotomy (DDFO) has been used to treat patients with recurrent patellar dislocation (RPD) with increased femoral anteversion. However, no study has reported second-look arthroscopic findings in the patellofemoral joint after DDFO.

PURPOSE

To report clinical and second-look arthroscopic outcomes for DDFO with combined medial patellofemoral ligament reconstruction (MPFL-R) in treating RPD with increased femoral anteversion.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From 2015 to 2019, 131 consecutive patients (144 knees) with RPD were treated with combined MPFL-R and DDFO. Patients with a femoral anteversion angle >30° and a minimum 2-year clinical follow-up period were included in the study. Three-dimensional computed tomography was performed to evaluate rotational deformities of the lower leg. Radiographic parameters presenting bony abnormalities associated with RPD were measured. Second-look arthroscopic evaluations were available for 86 knees to assess patellar tracking and chondral lesion changes. Moreover, clinical and radiologic outcomes were assessed pre- and postoperatively at a minimum 2 years.

RESULTS

A total of 102 knees in 92 patients were included in the present study with a mean clinical follow-up of 4.1 years (range, 2.0-5.6 years). Mean ± SD femoral anteversion changed significantly from 34.7°± 7.5° preoperatively to 11.3°± 0.2° postoperatively (P < .001), and mean tibial tubercle-trochlear groove distance decreased significantly from 19.6 ± 3.5 mm preoperatively to 17.4 ± 3.2 mm postoperatively (P < .001). In the majority of knees, at the time of second-look arthroscopic assessment, chondral lesion status remained unchanged at the lateral patellar facet (96%) and trochlear groove (95%); in contrast, chondral damage at the medial patellar facet was aggravated in 9 cases (10%). All functional scores (Tegner, Lysholm, visual analog scale, and Kujala scores) improved significantly at final follow-up. None of the patients experienced redislocation or subluxation after surgery.

CONCLUSION

Chondral lesions in the patellofemoral joint remained unchanged in the majority of cases in second-look arthroscopy after combined MPFL-R and DDFO. Moreover, high-grade trochlear dysplasia and arthroscopic residual patellar maltracking might be associated with cartilaginous deterioration at the medial patellar facet after surgery.

Chondral injuries in patients with recurrent patellar dislocation: a systematic review

Background

Patellar dislocations in patients presenting with recurrent patellofemoral instability can damage the surrounding structures, limiting patient’s participation to recreational activities and quality of life. This study evaluated frequency, location, and extent of associated injuries in patients with recurrent patellar dislocation.

Methods

This systematic review was conducted according to the PRISMA checklist. PubMed, Google scholar, Embase, and Web of Science databases were accessed in July 2021. All the published clinical studies reporting frequency, location, and extent of soft tissue lesions in patients with recurrent patellar dislocations were accessed.

Results

Data from 9 articles (232 patients) were retrieved. The mean age of the included patients was 21.2 ± 5.6 years. 84.8% of patients suffering from recurrent patellar dislocations demonstrated patellar chondral defects: medial facet (34.9%), while patellar crest (34.8%) and lateral facet (17%). 27.8% of patients demonstrated trochlear chondral injuries.

Conclusion

Chondral defects of the medial facet and the crest of the patella are the most common in patients with recurrent patellofemoral instability.

Management of Chondral Defects Associated with Patella Instability

Cartilage defects of the patellofemoral joint are commonly found in association with patellar instability owing to abnormal biomechanics. Strategies to address chondral defects of the patellofemoral joint secondary to instability should first address causes of recurrent instability. Most patellofemoral chondral defects associated with instability are less than 2 cm2 and do not generally require intervention beyond chondroplasty. Larger defects of the patella and/or the trochlea can be repaired with osteochondral or surface cartilage repair.

Recurrent patellar dislocations with patellar cartilage defects: A pain in the knee?

BACKGROUND

Recurrent patellar dislocation in combination with cartilage injures are difficult injuries to treat with confounding pathways of treatment. The aim of this study was to compare the clinical and functional outcomes of patients operated for patellofemoral instability with and without cartilage defects.

METHODS

Eighty-two patients (mean age 28.8 years) with recurrent patellar dislocations, who underwent soft-tissue or bony procedures, were divided into two matched groups (age, sex, follow up and type of procedure) of 41 each, based on the presence or absence of cartilage defects in patella. Chondroplasty, microfracture, osteochondral fixation or autologous matrix-induced chondrogenesis (AMIC)-type procedures were performed depending on the nature of cartilage injury. Lysholm, Kujala, Tegner and Subjective Knee scores of both groups were compared and analysed. Complications and return to surgery were noted.

RESULTS

With a mean follow up of 8 years, there was a significant improvement observed in all the mean postoperative patient-reported outcome measures of both groups, as compared with the preoperative scores (P < 0.05). Comparing the two groups, postoperative Lysholm, Kujala and Subjective knee scores were significantly higher in patients operated without cartilage defects (P < 0.05). Three patients operated for patellofemoral instability with cartilage defects underwent patellofemoral replacement subsequently. The odds ratio for developing complications was 2.53 for patients operated with cartilage defects.

CONCLUSION

Although there is a significant improvement in the long-term outcome scores of patients operated for recurrent patellar dislocation with cartilage defects, the results are significantly inferior compared with those without cartilage defects, along with a higher risk of developing complications and returning to surgery.

Comparative study of three different combination surgical methods for recurrent patella dislocation

PURPOSE

The effects of different combination of surgical techniques for recurrent patella dislocation (RPD) remain unclear. Thus, aim of this study was to investigate the surgical outcomes of different combination of surgical techniques for RPD.

METHODS

The clinical data of 79 patients with RPD from August 2014 to October 2016 were analysed retrospectively. Knee joint was assessed according to measurements of the congruence angle (CA), patellar tilt angle (PTA) and lateral patellofemoral angle (LPFA). Knee function was evaluated by Kujala patellofemoral score, Lysholm knee score and Tegner score. Patients were followed up by out-patient examination and telephone till October 2018.

RESULTS

Preoperative clinical characteristics were similar across groups. It was statistically insignificant among three groups in CA, PTA, LPFA and redislocation rate. In term of knee functions, the MPFL reconstruction and LPR release group had the highest score (Lysholm score: 91.82 ± 4.64, Kujala score: 94.22 ± 4.26, Tegner score: 5.80 ± 1.00, respectively) and the LPR release and MPR plication had the lowest score (Lysholm score: 78.10 ± 6.90, Kujala score: 80.91 ± 4.30, Tegner score: 4.98 ± 1.22, respectively).

CONCLUSION

Three combinations of surgical methods were similar in terms of postoperative joint congruence and redislocation rate, but MPFL reconstruction combined with LPR release is worthy to be promoted with the highest knee function scores.

Is Diagnostic Arthroscopy at the Time of Medial Patellofemoral Ligament Reconstruction Necessary?

Background:

Although medial patellofemoral ligament (MPFL) reconstruction is well described for patellar instability, the utility of arthroscopy at the time of stabilization has not been fully defined.

Purpose:

To determine whether diagnostic arthroscopy in conjunction with MPFL reconstruction is associated with improvement in functional outcome, pain, and stability or a decrease in perioperative complications.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent primary MPFL reconstruction without tibial tubercle osteotomy were reviewed (96 patients, 101 knees). Knees were divided into MPFL reconstruction without arthroscopy (n = 37), MPFL reconstruction with diagnostic arthroscopy (n = 41), and MPFL reconstruction with a targeted arthroscopic procedure (n = 23). Postoperative pain, motion, imaging, operative findings, perioperative complications, need for revision procedure, and postoperative Kujala scores were recorded.

Results:

Pain at 2 weeks and 3 months postoperatively was similar between groups. Significantly improved knee flexion at 2 weeks was seen after MPFL reconstruction without arthroscopy versus reconstruction with diagnostic and reconstruction with targeted arthroscopic procedures (58° vs 42° and 48°, respectively; P = .02). Significantly longer tourniquet times were seen for targeted arthroscopic procedures versus the diagnostic and no arthroscopic procedures (73 vs 57 and 58 min, respectively; P = .0002), and significantly higher Kujala scores at follow-up were recorded after MPFL reconstruction without arthroscopy versus reconstruction with diagnostic and targeted arthroscopic procedures (87.8 vs 80.2 and 70.1, respectively; P = .05; 42% response rate). There was no difference between groups in knee flexion, recurrent instability, or perioperative complications at 3 months. Diagnostic arthroscopy yielded findings not previously appreciated on magnetic resonance imaging (MRI) in 35% of patients, usually resulting in partial meniscectomy.

Conclusion:

Diagnostic arthroscopy with MPFL reconstruction may result in findings not previously appreciated on MRI. Postoperative pain, range of motion, and risk of complications were equal at 3 months postoperatively with or without arthroscopy. Despite higher Kujala scores in MPFL reconstruction without arthroscopy, the relationship between arthroscopy and patient-reported outcomes remains unclear. Surgeons can consider diagnostic arthroscopy but should be aware of no clear benefits in patient outcomes.

Functional properties of native and tissue-engineered cartilage toward understanding the pathogenesis of chondral lesions at the knee: A bovine cadaveric study

Chondral lesions frequently occur in different topographic locations of the knee. This study evaluated the functional properties among the articulating surfaces of the tibiofemoral and patellofemoral joints, and whether neo-cartilage engineered using chondrocytes from different knee locations would reflect these differences. The biomechanical properties of bovine cartilage isolated from eight locations within the tibiofemoral (medial and lateral condyle, medial and lateral tibial plateau) and patellofemoral joints (medial and lateral trochlea, medial and lateral patella) were examined. Tensile Young's moduli (tensile moduli) and aggregate moduli of the medial condyle were lower than those of the medial tibial plateau (6.11 ± 0.89 MPa vs. 7.19 ± 1.05 MPa, p = 0.04 and 354.4 ± 38.3 kPa vs. 419.4 ± 31.3 kPa, p = 0.002, respectively). Patella tensile and compressive moduli were lower than the trochlea (4.79 ± 2.01 MPa vs. 6.91 ± 2.46 MPa, p = 0.01 and 337.4 ± 37.2 kPa vs. 389.1 ± 38.3 kPa, p = 0.0005, respectively). Furthermore, chondrocytes from the above locations were used to engineer neo-cartilage, and its respective properties were evaluated. In neo-cartilage, medial condyle tensile and aggregate moduli were lower than in the medial tibial plateau (0.96 ± 0.23 MPa vs. 1.31 ± 0.31 MPa, p = 0.02, and 115.8 ± 26.0 kPa vs. 160.8 ± 18.8 kPa, p = 0.001, respectively). Compared to trochlear chondrocytes, neo-cartilage formed from patellar chondrocytes exhibited lower tensile and compressive moduli (1.16 ± 0.27 MPa vs. 0.74 ± 0.25 MPa, p < 0.001, and 109.1 ± 24.0 kPa vs. 82.5 ± 18.1 kPa, p < 0.001). A significant degree of disparity in biomechanical properties of the opposing articular surfaces was detected; the medial condyle and patella exhibited inferior properties compared to the opposing medial tibial plateau and trochlea, respectively. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2452-2464, 2017.

Evaluation of different surgical methods in treating recurrent patella dislocation after three-dimensional reconstruction

PURPOSE

Recurrent patella dislocation (RPD) is the most common complication of patellar instability. The effects of different surgical techniques on the outcome of RPD treatments remain unclear. This study was conducted to compare the effects of three surgical techniques in treating RPD by three-dimensional (3D) reconstruction from computed tomography (CT) scans.

METHODS

Sixty-eight patients with RPD and no previous surgical treatments who attended our hospital between October 2010 and 2013 were enrolled and randomly assigned into three groups: (1) medial patellofemoral ligament (MPFL) reconstruction and medial patellar retinaculum (MPR) plication group; (2) lateral patellar retinaculum (LPR) release and MPR plication group; and (3) MPFL reconstruction and LPR release group. Knee joints with flexion of 20° were scanned by a 64-row CT scanner and 3D reconstructed. Congruence angle (CA), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), and congruence of the lateral patellofemoral articular surface were measured. Knee joint function was evaluated by the Lysholm knee scoring scale, Kujala patellofemoral score, and International Knee Documentation Committee (IKDC) score.

RESULTS

Pre-operative clinical characteristics were similar across groups. After treatment, the CA, PTA, and LPFA were reverted to normal post-operatively without statistically significant between-group differences. The MPFL reconstruction and LPR release group had the highest congruence of the lateral patellofemoral articular surface; while the (LPR) release and (MPR) plication group had the lowest Lysholm knee scoring scale, Kujala patellofemoral score, and IKDC score after surgery.

CONCLUSIONS

The MPFL reconstruction and LPR release group had the best clinical outcomes among the three surgical methods, as indicated by better joint congruence after 3D joint reconstruction and higher knee function scores.

Patella instability in children and adolescents

Patellar instabilities are the most common knee pathologies during growth. Congenital dislocations are rare. Extensive, early soft tissue releases relocate the extensor mechanism and may enable normal development of the femoro-patellar anatomy.Conservative management is the preferred strategy after a 'first-time' traumatic dislocation. In cases with concomitant anatomical predisposing factors such as trochlear dysplasia, malalignment, malrotation or ligamentous laxity, surgical reconstruction must be considered. The same applies to recurrent dislocations with pain, a sense of instability or re-dislocations which may also lead to functional compensatory mechanisms (quadriceps-avoiding gait in knee extension) or cartilaginous lesions with subsequent patello-femoral osteoarthritis. The decision-making process guiding surgical re-alignment includes analysis with standard radiographs and MRI of the trochlear groove, joint cartilage and medial patello-femoral ligament (MPFL). Careful evaluation of dynamic and static stabilisers is essential: the medial patello-femoral ligament provides stability during the first 20° of flexion, and the trochlear groove thereafter.Excessive femoral anteversion, general ligamentous laxity with increased femoro-tibial rotation, patella alta and increased distance between the tibial tuberosity and the trochlear groove must also be taken into account and surgically corrected.In cases with ongoing dislocations during skeletal immaturity, soft tissue procedures must suffice: reconstruction of the medial patello-femoral ligament as a standalone procedure or in conjuction with more complex distal realignment of the quadriceps mechanism may lead to a permanent stable result, or at least buys time until a definitive bony procedure is performed. Cite this article: Hasler CC, Studer D. Patella instability in children and adolescents. EFORT Open Rev 2016;1:160-166. DOI: 10.1302/2058-5241.1.000018.

How to Deal With Chronic Patellar Instability: What Does the Literature Tell Us?

CONTEXT

Patellar instability is a common clinical problem, affecting between 7 and 49 people per 100,000. However, not all patellar instabilities are equal, the etiology of the disorder is multifactorial, and a clear understanding of the cause of instability is crucial for appropriate surgical treatment. The goal of this article is to identify how to best treat patellar instability to provide good outcomes and hopefully prevent future osteoarthritis.

EVIDENCE ACQUISITION

A PubMed search from 1983 through May 2015.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Several subpopulations of patients with chronic patellar instability exist: (1) lateral patellar instability during the early arc of knee flexion (0°-30°), (2) lateral patellar instability persisting beyond 30° of knee flexion, (3) lateral patellar instability in greater knee flexion, and (4) medial patellar instability. In patients with lateral instability during the early arc of knee flexion, the medial patellofemoral deficiency is the essential lesion. Persistent instability beyond 30° of knee flexion suggests an unusually high patella, severe trochlear dysplasia, pathologic increment of the tibial tuberosity-trochlear groove distance, or a combination of these factors. In patients with lateral instability in greater knee flexion, increasing and unbalanced tension in the extensors pulls the patella out of the groove as the knee is flexed. Finally, medial patellar instability is an objective iatrogenic condition that appears after realignment surgery in the vast majority of cases.

CONCLUSION

The etiology of chronic patellar instability is multifactorial, and its treatment must therefore be personalized.

STRENGTH OF RECOMMENDATION TAXONOMY SORT

B.