Surgical versus non-surgical interventions for treating patellar dislocation

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.

A systematic review and meta-analysis comparing conservative and surgical treatments for acute patellar dislocation in children and adolescents

PURPOSE

This study sought to clarify treatment evidence to treat patellar dislocation by evaluating which treatment could yield better improvement of clinical outcomes for acute patellar dislocation in children and adolescents 18 years of age or younger.

MATERIALS AND METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials electronic databases were searched for relevant articles comparing clinical outcomes of conservative and surgical treatments for acute patellar dislocation in children and adolescents published from March 2008 to August 2022. Data searching, extraction, analysis, and quality assessment were performed on the basis of the Cochrane Collaboration guidelines. The quality assessment of each study was investigated using the Physiotherapy Evidence Database (PEDro) critical appraisal scoring system and Newcastle-Ottawa Quality Assessment Scale scores. To calculate the overall combined effect size for each outcome, Review Manager Version 5.3 (The Cochrane Collaboration, Software Update, Oxford) was employed.

RESULTS

Three randomized controlled trials (RCTs) and one prospective study were investigated. In terms of pain [mean difference (MD) 6.59, 95% confidence interval (CI) 1.73-11.45, I2 0%], there were significantly better outcomes in conservative group. Nevertheless, there were no significant differences in any evaluated outcomes such as redislocation [risk ratio (RR) 1.36, 95% CI 0.72-2.54, I2 65%], Kujala score (MD 3.92, 95% CI -0.17 to 8.01, I2 0%), Tegner score (MD 1.04, 95% CI -0.04 to 2.11, I2 71%), or subjective results (RR 0.99, 95% CI 0.74-1.34, I2 33%) between conservative and surgical treatment groups.

CONCLUSIONS

Despite better pain outcomes with conservative group, the present study revealed no significant differences in clinical outcomes between conservative treatment and surgical treatment in children and adolescents with acute patellar dislocation. Since there are no significant differences in clinical outcomes between the two groups, routine surgical treatment is not advocated for treating acute patellar dislocation in children and adolescents.

Surgical versus non-surgical interventions for treating patellar dislocation

BACKGROUND

Patellar (knee cap) dislocation occurs when the patella disengages completely from the trochlear (femoral) groove. It affects up to 42/100,000 people, and is most prevalent in those aged 20 to 30 years old. It is uncertain whether surgical or non-surgical treatment is the best approach. This is important as recurrent dislocation occurs in up to 40% of people who experience a first time (primary) dislocation. This can reduce quality of life and as a result people have to modify their lifestyle. This review is needed to determine whether surgical or non-surgical treatment should be offered to people after patellar dislocation.

OBJECTIVES

To assess the effects (benefits and harms) of surgical versus non-surgical interventions for treating people with primary or recurrent patellar dislocation.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, AMED, CINAHL, Physiotherapy Evidence Database and trial registries in December 2021. We contacted corresponding authors to identify additional studies.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled clinical trials evaluating surgical versus non-surgical interventions for treating primary or recurrent lateral patellar dislocation in adults or children.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent patellar dislocation, and patient-rated knee and physical function scores. Our secondary outcomes were health-related quality of life, return to former activities, knee pain during activity or at rest, adverse events, patient-reported satisfaction, patient-reported knee instability symptoms and subsequent requirement for knee surgery. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included 10 studies (eight randomised controlled trials (RCTs) and two quasi-RCTs) of 519 participants with patellar dislocation. The mean ages in the individual studies ranged from 13.0 to 27.2 years. Four studies included children, mainly adolescents, as well as adults; two only recruited children. Study follow-up ranged from one to 14 years. We are unsure of the evidence for all outcomes in this review because we judged the certainty of the evidence to be very low. We downgraded each outcome by three levels. Reasons included imprecision (when fewer than 100 events were reported or the confidence interval (CI) indicated appreciable benefits as well as harms), risk of bias (when studies were at high risk of performance, detection and attrition bias), and inconsistency (in the event that pooled analysis included high levels of statistical heterogeneity). We are uncertain whether surgery lowers the risk of recurrent dislocation following primary patellar dislocation compared with non-surgical management at two to nine year follow-up. Based on an illustrative risk of recurrent dislocation in 348 people per 1000 in the non-surgical group, we found that 157 fewer people per 1000 (95% CI 209 fewer to 87 fewer) had recurrent dislocation between two and nine years after surgery (8 studies, 438 participants). We are uncertain whether surgery improves patient-rated knee and function scores. Studies measured this outcome using different scales (the Tegner activity scale, Knee Injury and Osteoarthritis Outcome Score, Lysholm, Kujala Patellofemoral Disorders score and Hughston visual analogue scale). The most frequently reported score was the Kujala Patellofemoral Disorders score. This indicated people in the surgical group had a mean score of 5.73 points higher at two to nine year follow-up (95% CI 2.91 lower to 14.37 higher; 7 studies, 401 participants). On this 100-point scale, higher scores indicate better function, and a change score of 10 points is considered to be clinically meaningful; therefore, this CI includes a possible meaningful improvement. We are uncertain whether surgery increases the risk of adverse events. Based on an assumed risk of overall incidence of complications during the first two years in 277 people out of 1000 in the non-surgical group, 335 more people per 1000 (95% CI 75 fewer to 723 more) had an adverse event in the surgery group (2 studies, 144 participants). Three studies (176 participants) assessed participant satisfaction at two to nine year follow-up, reporting little difference between groups. Based on an assumed risk of 763 per 1000 non-surgical participants reporting excellent or good outcomes, seven more participants per 1000 (95% CI 199 fewer to 237 more) reported excellent or good satisfaction. Four studies (256 participants) assessed recurrent patellar subluxation at two to nine year follow-up. Based on an assumed risk of patellar subluxation in 292 out of 1000 in the non-surgical group, 73 fewer people per 1000 (95% CI 146 fewer to 35 more) had patellar subluxation as a result of surgery. Slightly more people had subsequent surgery in the non-surgical group. Pooled two to nine year follow-up data from three trials (195 participants) indicated that, based on an assumed risk of subsequent surgery in 215 people per 1000 in the non-surgical group, 118 fewer people per 1000 (95% CI 200 fewer to 372 more) had subsequent surgery after primary surgery.

AUTHORS' CONCLUSIONS

We are uncertain whether surgery improves outcome compared to non-surgical management as the certainty of the evidence was very low. No sufficiently powered trial has examined people with recurrent patellar dislocation. Adequately powered, multicentre, randomised trials are needed. To inform the design and conduct of these trials, expert consensus should be achieved on the minimal description of both surgical and non-surgical interventions, and the pathological variations that may be relevant to both choice of these interventions.

Synthetic graft for medial patellofemoral ligament reconstruction: a systematic review

Background

This systematic review investigates the role of synthetic graft for primary medial patellofemoral ligament (MPFL) reconstruction in patients with recurrent patellofemoral instability, focusing on clinical scores and the rate of complications.

Methods

This systematic review was conducted according to the PRISMA statement. The main online databases were accessed in January 2022 without time constraints. All clinical studies investigating the use of synthetic grafts for MPFL reconstruction were accessed. Revision settings were not considered. Only articles reporting data on patients with recurrent patellofemoral instability were eligible. Studies regarding congenital or acute patellofemoral dislocation were excluded. Only studies performing a follow-up longer than 24 months were considered.

Results

Data on 199 patients [mean age 22.3 (range 19.0–28.0) years] were collected. The mean follow-up was 60.5 (39.0–142.8) months. All the scores of interest improved at last follow-up: Kujala (+ 24.8; P = 0.0002), Lysholm (+ 42.0; P = 0.02), Tegner (+ 1.2; P = 0.03), IKDC (+ 20.9; P = 0.02). Post-operatively, a positive apprehension test was detected in 6.1% (7/115) of patients, and a sensation of instability was reported by 1.5% (3/199) of patients. The rate of re-dislocations was 2.5% (5 of 199 patients), and revision procedures were performed in less than 1% (1 of 199) of patients.

Conclusion

Synthetic graft may be reliable and feasible for primary MPFL reconstruction in patients with recurrent patellofemoral instability.

A Randomized Controlled Trial Comparing a Patella-Stabilizing, Motion-Restricting Knee Brace Versus a Neoprene Nonhinged Knee Brace After a First-Time Traumatic Patellar Dislocation

BACKGROUND

A traumatic lateral patellar dislocation is a common injury in adolescents and young adults. The majority of first-time dislocations can be treated nonoperatively. Various types of knee braces are used for nonoperative treatment, but evidence on the most preferable bracing method is lacking.

PURPOSE

To evaluate the efficacy of a patella-stabilizing, motion-restricting knee brace versus a neoprene nonhinged knee brace for the treatment of a first-time traumatic patellar dislocation at 3 years of follow-up.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 101 skeletally mature patients with a first-time traumatic patellar dislocation were enrolled in the study. After exclusion criteria were applied, 79 patients with a first-time traumatic patellar dislocation were randomized and allocated into 2 study groups: group A, with a patella-stabilizing, motion-restricting knee brace (hinged to allow knee range of motion [ROM] of 0°-30°) and group B, with a neoprene nonhinged knee brace (not restricting any knee motion). Both groups received similar physical therapy instructions and were advised to use the brace continuously for 4 weeks. Overall, 64 patients completed the trial.

RESULTS

The redislocation rate in group A was 34.4% (11/32) and in group B it was 37.5% (12/32) (risk difference, -3.1% [95% CI, -26.6% to 20.3%]; P = .794). Patients in group A had less knee ROM than those in group B at 4 weeks (90° vs 115°, respectively; P < .001) and 3 months (125° vs 133°, respectively; P = .028). Patients in group A had more quadriceps muscle atrophy than patients in group B at 4 weeks (24/32 vs 16/32, respectively; P = .048) and 3 months. At 6 months, patients in group B reported better functional outcomes than patients in group A (Kujala score mean difference, 4.6; P = .012), although no clinically relevant difference was found at 3 years.

CONCLUSION

The use of a patella-stabilizing, motion-restricting knee brace for 4 weeks after a first-time traumatic patellar dislocation did not result in a statistically significant reduction in redislocations versus a neoprene nonhinged knee brace, although this trial was underpowered to detect more modest differences. Knee immobilization was associated with quadriceps muscle atrophy, less knee ROM, and worse functional outcomes in the first 6 months after the injury.

REGISTRATION

NCT01344915 (ClinicalTrials.gov identifier).

Surgical Correction of Non-traumatic Patella Maltracking. Midterm Clinical Follow-up

BACKGROUND

Patellar instability comprises a group of pathologies that allow the patella to move out of its trajectory within the trochlear groove during walking. Symptomatic patients who need surgery commonly undergo soft tissue procedures such as medial patellofemoral ligament repair to strengthen the ligaments that hold the patella in place. However, soft-tissue repairs may be insufficient in patients suffering from patellar maltracking, which is characterized by an unbalanced gliding of the patella within its route. In these patients, a different approach is advised. We aim to provide the mid-term clinical outcomes of the Fulkerson distal realignment operation in selected patients with non-traumatic patellar maltracking.

METHODS

The clinical outcomes of the Fulkerson distal realignment operation performed in 22 knees of 21 patients were evaluated by a self-administered subjective International Knee Documentation Committee (IKDC) score and the Tegner-Lysholm knee scoring scale.

RESULTS

Before surgery, the median IKDC score was 52, and the median Tegner-Lysholm score was 56. Following surgery (mean follow-up 48 months, range 24-156), the median IKDC and the Tegner-Lysholm scores were 67 and 88, respectively. The improvement was statistically significant (P=0.001 and P=0.002 for IKDC and Tegner-Lysholm scores, respectively). Associated procedures included patella microfracture due to grade III-IV cartilage lesion (International Cartilage Repair Society grading system) in four patients, retinacular releases in three patients, medial capsular augmentations in two patients, and medial patellofemoral ligament reconstruction in two patients. One patient with Ehlers-Danlos disease required excessive medialization of the tibial tuberosity. Surgery-related complications occurred in three patients.

DISCUSSION

Surgical correction of patellar maltracking with Fulkerson distal realignment combined with associated procedures in individual patients was associated with an increase in subjective and functional clinical scores at medium-term follow-up. Particular attention should address pathologies associated with patellar maltracking and managed accordingly.

LEVEL OF EVIDENCE

4c (case series).

Arthroscopically reduced, irreducible patella dislocation

Acute patella dislocations account for approximately 2%-3% of knee injuries and are therefore a relatively common presentation in the accident and emergency department. The majority of patella dislocations can be reduced with simple manoeuvres or even spontaneously and can be managed conservatively by bracing and rehabilitation. The aim of this study is to identify and review the main causes of the unique and unexpected event of irreducible patella dislocation and their characteristic presentations. Irreducible patella dislocations can happen but are very rare. Currently, a limited number of case reports are available, prompting for a need for research on this topic. This case study can shed light on the possible pathogenesis and pathognomonic features of irreducible patella dislocations and provide insight on the available therapeutic approaches.

Chondral and Soft Tissue Injuries Associated to Acute Patellar Dislocation: A Systematic Review

INTRODUCTION

Chondral and soft tissue injuries can be associated with first time patellar dislocation, but it is unclear how common they are, and which tissues are affected. A systematic review of the literature was performed to investigate the frequency, location, and extent of chondral and medial patellofemoral ligament (MPFL) injuries in patients following first time patellar dislocation.

METHODS

This systematic review was conducted according to the PRISMA guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in November 2021. All the published clinical studies reporting the frequency, location, and extent of soft tissue lesions following first time patellar dislocation were accessed. Studies reporting data on habitual, congenital, or recurrent patellofemoral instability were excluded.

RESULTS

Data from 42 articles (2254 patients, mean age 21.6 ± 7.3 years) were retrieved. Ninety-eight percent of patients who experienced first time patellar dislocation demonstrated MPFL rupture at MRI. Forty-eight percent of MPFL ruptures were located at the patellar side, 34% at the femoral insertion site, and 18% in the midportion. Eighty-five percent of patients showed signs of patellar chondral damage at MRI, and trochlear chondral injuries were evidenced in 47% of patients. Intra-articular loose bodies were observed in 11.5% of patients. At arthroscopy, the medial facet and the crest of the patella more commonly exhibited chondral lesions than the lateral facet and femoral trochlea.

CONCLUSIONS

Most patients suffer chondral damage and MPFL tears following after a first time patellar dislocation.

Magnetic Resonance Imaging Features of Traumatic Patellofemoral Dislocation

Acute traumatic patellar dislocations are encountered with relative frequency, making up 3% of all knee injuries. Typically witnessed in younger patients following sporting injuries, this injury can be debilitating, potentially leading to recurrent dislocation, pain, reduction in activity and patellofemoral osteoarthritis.

Management of this injury remains controversial, and as such detailed magnetic resonance imaging (MRI) is increasingly recommended to help illustrate the exact nature of osteochondral and soft tissue injury, with a view to assessing the anatomical sequelae of patellar dislocation as well as the potential of recurrence and dictating the need for either conservative or surgical management in the acute setting. As such, awareness of the typical MRI findings in traumatic patellar dislocations may potentially aid in pursuing appropriate intervention for this pathology.

This case describes a 33-year-old gentleman presenting to the emergency department following patellar dislocation. After failed departmental closed reduction, this patient progressed on to definitive anatomical MRI assessment followed by acute surgical intervention in the form of medial patellofemoral ligament (MPFL) repair. This case allows for both illustration and discussion of typical radiological features associated with traumatic patellar dislocation.

Medial Patella Femoral Ligament Reconstruction With Periosteal Tunnels and Suture Fixation

Lateral patellar dislocations can damage the medial patella femoral ligament. Nonoperative care is preferred but some tears may require a surgical intervention. Patella fractures are considered a risk factor after surgery. The technique described in this Technical Note avoids any bone tunnel drilling, which may eliminate the possibility of a patella fracture. The surgical procedure uses periosteal fibro-osseous tunnels to a double-limbed gracilis graft to reconstruct the upper and lower borders as conventionally used for medial patella femoral ligament reconstruction. Once the graft is tensioned, it is sutured to the periosteal fibro-osseous tunnel with 2 sutures on the medial side and at least 1 suture on the lateral side of each periosteal fibro-osseous sleeve. Each of the 2 periosteal fibro-osseous tunnels has 3 to 4 sutures securing the graft. After surgery, the patients complete 5 phases of rehabilitation to reduce swelling and to regain their strength and range of motion.

I.S.Mu.L.T. first-time patellar dislocation guidelines

Primary traumatic patellar dislocation is common, particularly in young active individuals. A consensus on its management is still lacking. The present work provides easily accessible guidelines to be considered as recommendations for a good clinical practice developed through a process of systematic review of the literature and expert opinion, to improve the quality of care and rationalize the use of resources.

LEVEL OF EVIDENCE

Ia.

Surgical versus conservative management of acute patellar dislocation in children and adolescents: a systematic review

PURPOSE

The goal of this study was to perform a comparative review to determine whether there is a significant difference in the rate of repeat dislocation and clinical outcome between surgical and conservative management of acute patellar dislocation in children and adolescents.

METHODS

A systematic review of the MEDLINE database was performed. English-language clinical outcome studies with a primary outcome/treatment specific to acute patella dislocation in a paediatric population were included. Eleven studies met inclusion criteria; Chi-square analysis, independent t tests and weighted mean pooled cohort statistics were performed where appropriate.

RESULTS

A total of 470 conservatively managed and 157 operatively treated knees were included. Conservatively managed patients were on average 17.0 years and had a mean follow-up of 3.9 years; surgically managed patients were on average 16.1 years and had a mean follow-up of 4.7 years. Conservatively managed knees had a 31% rate of recurrent dislocation rate compared to 22% in surgical knees (p = 0.04). Trochlear dysplasia and skeletal immaturity confer greater risk for recurrent instability. Surgical treatment may provide clinically important quality of life and sporting benefit.

CONCLUSIONS

Surgical treatment of first time patella dislocation in children and adolescents is associated with a lower risk of recurrent dislocation and higher health-related quality of life and sporting function. There is a paucity of evidence on MPFL reconstruction for first time traumatic patella dislocation in this population.

LEVEL OF EVIDENCE

IV.

Is surgical treatment better than conservative treatment for primary patellar dislocations? A meta-analysis of randomized controlled trials

BACKGROUND

Despite several randomized controlled trials comparing operative to nonoperative management of primary patellar dislocation, the optimal management of this condition remains a subject of controversy. The aim of this study was to compare surgical to conservative treatment of outcomes for primary patellar dislocation by meta-analysis all the relative randomized controlled trials.

STUDY DESIGN

Meta-analysis.

METHODS

After searching multiple online databases (MEDILINE, EMBASE, CLINICAL, OVID, BISOS and Cochrane registry of controlled clinical trials), eight randomized controlled trials including 430 patients were meta-analyzed in which operative treatment was compared with non-operative treatment for primary patellar dislocation. Outcomes evaluated were redislocation rate, Kujala score, episode of instability, Tegner activity score, Hughston visual analog score (VAS) and patient satisfaction.

RESULTS

Outcomes on recurrent patellar dislocation (P = 0.004) and Hughston VAS (P = 0.03) were statistically significant in favor of operative management. Tegner activity score (P < 0.00001) was significantly higher in favor of conservative treatment, though only a few studies were identified. There was no significant difference between the two treatments regarding episode of instability (P = 0.41), Kujala score (P = 0.32) or patient satisfaction (P = 0.49).

CONCLUSION

Surgical treatment may be better than conservative treatment for patients with primary patellar dislocation on incidence of redislocation. However, since these findings are built on a limited number of studies available, well-designed, multicenter clinical trials with long-term follow-up are required to provide more solid evidence concerning optimal strategies.

Management of Acute Patellar Dislocation: A Case Report

OBJECTIVE

The purpose of this case study is to describe the evaluation and management of patellar dislocations and the different approaches used from providers in different countries.

CLINICAL FEATURES

An individual dislocated her left patella while traveling abroad and received subsequent care in Thailand, China, and the United States.

INTERVENTION AND OUTCOME

Nonoperative treatment protocols including manual closed reduction of the patella, casting of the leg, and rehabilitation exercises were employed.

CONCLUSION

Receipt of care when abroad can be challenging. The patient's knee range of motion and pain continued to improve when she was diligent about performing the home exercise program. This case highlights the importance of a thorough examination, a proper regimen of care, and patient counseling to ensure a full recovery and minimize the chance of re-injury.

Six-year outcome after non-surgical versus surgical treatment of acute primary patellar dislocation in adolescents: a prospective randomized trial

PURPOSE

There is only one prospective randomized trial on acute primary patellar dislocation in adolescents comparing the long-term outcome after conservative versus operative procedures. Therefore, the long-term outcome, patellar redislocation rate, and functional outcome after conservative versus operative procedures were investigated in a prospective randomized study.

METHODS

Initially, 36 patients with acute primary patellar dislocation were prospectively randomized to conservative (n = 20) versus operative procedures (n = 16) and 30 of them (83%), 15/20 with conservative and 15/16 with operative procedures, were reached for a follow-up interview 6 years after primary procedure.

RESULTS

Baseline and clinical parameters were similar in the two groups. The prevalence of patellar redislocation rate at 3 and 6 years after primary procedure was higher in the conservative group (7/20, 35%, 3 years and 11/15, 73%, 6 years) versus in the operative group (0/16, 0%, 3 years and 5/15, 33%, 6 years) (p = 0.02). The knee function was slightly better 6 years after primary treatment in the operative group than in the conservative group. Most patients in both groups had excellent or good knee function at 6-year follow-up, but four patients (4/15, 27%) in conservative group and two patients (2/15, 13%) in operative group had poor knee function at 6-year follow-up. Four patients in conservative group (4/15, 27%) and two patients in the operative group (2/15, 13%) were unsatisfied with the procedure at 6-year follow-up.

CONCLUSIONS

In conclusion, the results suggest that both conservative and operative procedures are feasible options for treatment of acute primary patellar dislocation in adolescents. A new finding with clinical relevance in the present work is a significantly higher redislocation rate in conservative group compared to operative group after 6-year follow-up in acute primary patellar dislocation in adolescents.

LEVEL OF EVIDENCE

II.

Current Concepts for Patellar Dislocation

Context:

Patellar dislocation usually occurs to the lateral side, leading to ruptures of the Medial Patellofemoral Ligament (MPFL) in about 90% of the cases. Even though several prognostic factors are identified for patellofemoral instability after patellar dislocation so far, the appropriate therapy remains a controversial issue.

Evidence Acquisition:

Authors searched the Medline library for studies on both surgical and conservative treatment for patellar dislocation and patellofemoral instability. Additionally, the reference list of each article was searched for additional studies.

Results:

A thorough analysis of the anatomical risk factors with a particular focus on patella alta, increased Tibial Tuberosity-Trochlear Groove (TT-TG) distance, trochlear dysplasia as well as torsional abnormalities should be performed early after the first dislocation to allow adequate patient counseling. Summarizing the results of all published randomized clinical trials and comparing surgical and conservative treatment after the first-time patellar dislocation until today indicated no significant evident difference for children, adolescents, and adults. Therefore, nonoperative treatment was indicated after a first-time patellar dislocation in the vast majority of patients.

Conclusions:

Surgical treatment for patellar dislocation is indicated primarily in case of relevant concomitant injuries such as osteochondral fractures, and secondarily for recurrent dislocations.

Surgical versus conservative treatment of primary patellar dislocation. A systematic review and meta-analysis

PURPOSE

The purpose of this study was to determine the efficacy of surgical and conservative treatment in the prevention of recurrence after primary patellar dislocation.

METHODS

Studies were searched on MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and CINHAL from their inception to April 2015. All randomized controlled clinical trials comparing surgical versus conservative treatment after first patellar dislocation were included. Primary outcomes were: recurrent dislocation, subluxation, overall instability and subsequent surgery. Secondary outcomes included imaging, and subjective and objective clinical assessment tools. Methodological quality of the studies was assessed using Cochrane Collaboration's "Risk of Bias" tool. Pooled analyses were reported as risk ratio (RR) using a random effects model. Continuous data were reported as standardized mean difference (SMD) and 95 % confidence intervals (CIs). Heterogeneity was assessed using I².

RESULTS

Nine studies were included in the meta-analyses. Methodological quality of the studies was moderate to low. Meta-analyses showed that surgical treatment significantly reduces the redislocation rate (RR = 0.62; 95% CI = 0.39, 0.98, p = 0.04) and provides better results on Hughston VAS score (SMD = -0.32; 95% CI = -0.61, -0.03; p = 0.03) and running (OR = -0.52; 95% CI = 0.31, 0.88; p = 0.01). Conservative treatment showed less occurrence of minor complications (OR = 3.46; 95% CI = 2.08, 5.77; p = 0.01) and better results in the figure-of-8 run test (SMD = 0.42; 95% CI = 0.06, 0.77; p = 0.02) and in the squat down test (SMD = -0.45; 95% CI = -0.81, -0.10; p < 0.00001). No other significant differences could be found.

CONCLUSIONS

Based on the available data, surgical treatment of primary patella dislocation significantly reduces the risk of patella redislocation.

Evaluation and management of patellar instability in pediatric and adolescent athletes

CONTEXT

The rising popularity and intensity of youth sports has increased the incidence of patellar dislocation. These sports-related injuries may be associated with significant morbidity in the pediatric population. Treatment requires understanding and attention to the unique challenges in the skeletally immature patient.

EVIDENCE ACQUISITION

PubMed searches spanning 1970-2013.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

Although nonoperative approaches are most often suitable for first-time patellar dislocations, surgical treatment is recommended for acute fixation of displaced osteochondral fractures sustained during primary instability and for patellar realignment in the setting of recurrent instability. While a variety of procedures can prevent recurrence, the risk of complications is not minimal.

CONCLUSION

Patellar stabilization and realignment procedures in skeletally immature patients with recurrent patellar dislocation can effectively treat patellar instability without untoward effects on growth if careful surgical planning incorporates protection of growth parameters in the skeletally immature athlete.

Surgical versus non-surgical interventions for treating patellar dislocation

BACKGROUND

Patellar dislocation occurs when the patella disengages completely from the trochlear (femoral) groove. Following reduction of the dislocation, conservative (non-surgical) rehabilitation with physiotherapy may be used. Since recurrence of dislocation is common, some surgeons have advocated surgical intervention rather than non-surgical interventions. This is an update of a Cochrane review first published in 2011.

OBJECTIVES

To assess the effects (benefits and harms) of surgical versus non-surgical interventions for treating people with primary or recurrent patellar dislocation.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group's Specialised Register, the Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE, EMBASE, AMED, CINAHL, ZETOC, Physiotherapy Evidence Database (PEDro) and a variety of other literature databases and trial registries. Corresponding authors were contacted to identify additional studies. The last search was carried out in October 2014.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled clinical trials evaluating surgical versus non-surgical interventions for treating lateral patellar dislocation.

DATA COLLECTION AND ANALYSIS

Two review authors independently examined titles and abstracts of each identified study to assess study eligibility, extract data and assess risk of bias. The primary outcomes we assessed were the frequency of recurrent dislocation, and validated patient-rated knee or physical function scores. We calculated risk ratios (RR) for dichotomous outcomes and mean differences MD) for continuous outcomes. When appropriate, we pooled data.

MAIN RESULTS

We included five randomised studies and one quasi-randomised study. These recruited a total of 344 people with primary (first-time) patellar dislocation. The mean ages in the individual studies ranged from 19.3 to 25.7 years, with four studies including children, mainly adolescents, as well as adults. Follow-up for the full study populations ranged from two to nine years across the six studies. The quality of the evidence is very low as assessed by GRADE (Grading of Recommendations Assessment, Development and Evaluation Working Group) criteria, with all studies being at high risk of performance and detection biases, relating to the lack of blinding.There was very low quality but consistent evidence that participants managed surgically had a significantly lower risk of recurrent dislocation following primary patellar dislocation at two to five years follow-up (21/162 versus 32/136; RR 0.53 favouring surgery, 95% confidence interval (CI) 0.33 to 0.87; five studies, 294 participants). Based on an illustrative risk of recurrent dislocation in 222 people per 1000 in the non-surgical group, these data equate to 104 fewer (95% CI 149 fewer to 28 fewer) people per 1000 having recurrent dislocation after surgery. Similarly, there is evidence of a lower risk of recurrent dislocation after surgery at six to nine years (RR 0.67 favouring surgery, 95% CI 0.42 to 1.08; two studies, 165 participants), but a small increase cannot be ruled out. Based on an illustrative risk of recurrent dislocation in 336 people per 1000 in the non-surgical group, these data equate to 110 fewer (95% CI 195 fewer to 27 more) people per 1000 having recurrent dislocation after surgery.The very low quality evidence available from single trials only for four validated patient-rated knee and physical function scores (the Tegner activity scale, KOOS, Lysholm and Hughston VAS (visual analogue scale) score) did not show significant differences between the two treatment groups.The results for the Kujala patellofemoral disorders score (0 to 100: best outcome) differed in direction of effect at two to five years follow-up, which favoured the surgery group (MD 13.93 points higher, 95% CI 5.33 points higher to 22.53 points higher; four studies, 171 participants) and the six to nine years follow-up, which favoured the non-surgical treatment group (MD 3.25 points lower, 95% CI 10.61 points lower to 4.11 points higher; two studies, 167 participants). However, only the two to five years follow-up included the clear possibility of a clinically important effect (putative minimal clinically important difference for this outcome is 10 points).Adverse effects of treatment were reported in one trial only; all four major complications were attributed to the surgical treatment group. Slightly more people in the surgery group had subsequent surgery six to nine years after their primary dislocation (20/87 versus 16/78; RR 1.06, 95% CI 0.59 to 1.89, two studies, 165 participants). Based on an illustrative risk of subsequent surgery in 186 people per 1000 in the non-surgical group, these data equate to 11 more (95% CI 76 fewer to 171 more) people per 1000 having subsequent surgery after primary surgery.

AUTHORS' CONCLUSIONS

Although there is some evidence to support surgical over non-surgical management of primary patellar dislocation in the short term, the quality of this evidence is very low because of the high risk of bias and the imprecision in the effect estimates. We are therefore very uncertain about the estimate of effect. No trials examined people with recurrent patellar dislocation. Adequately powered, multi-centre, randomised controlled trials, conducted and reported to contemporary standards, are needed. To inform the design and conduct of these trials, expert consensus should be achieved on the minimal description of both surgical and non-surgical interventions, and the anatomical or pathological variations that may be relevant to both choice of these interventions and the natural history of patellar instability. Furthermore, well-designed studies recording adverse events and long-term outcomes are needed.

Anterior knee pain caused by patellofemoral pain syndrome can be relieved by Botulinum toxin type A injection

OBJECTIVE

To investigate the therapeutic effects of Botulinum toxin type A (BTA) for anterior knee pain caused by patellofemoral pain syndrome (PFPS).

DESIGN

Prospective case control study for intervention.

SETTING

A tertiary hospital rehabilitation center.

PARTICIPANTS

Twelve bilateral PFPS patients with anterior knee pain were recruited. The worse pain knee was selected for injection, and the counterpart was left untreated.

INTERVENTION

Injection of BTA to vastus lateralis (VL) muscle.

MAIN OUTCOME MEASURES

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to assess pain, stiffness, and functional status of the knee, and CYBEX isokinetic dynamometer to assess isokinetic muscle force before and after BTA application to VL.

RESULTS

Remarkable improvement after receiving BTA injection was obtained not only in the questionnaire of WOMAC (p<0.05), but also in knee flexion torque (p<0.05). No significant change of knee extension torque was noted (p=0.682).

CONCLUSION

BTA injection is a good alternative treatment to improve anterior knee pain, knee function and isokinetic flexion torque.

Patellar instability

Patellar instability is a common injury that can result in significant limitations of activity and long-term arthritis. There is a high risk of recurrence in patients and operative management is often indicated. Advances in the understanding of patellofemoral anatomy, such as knowledge about the medial patellofemoral ligament, tibial tubercle-trochlear groove distance, and trochlear dysplasia may allow improved surgical management of patellar instability. However, techniques such as MPFL reconstruction are technically demanding and may result in significant complication. The role of trochleoplasty remains unclear.

Which patellae are likely to redislocate?

PURPOSE

The purpose of this study was to identify the risk factors for recurrent lateral patellar dislocations and to incorporate those factors into a patellar instability severity score.

METHODS

Sixty-one patients [male/female 35/26; median age 19 years (range 9-51 years)] formed the study group for this investigation. Within the study group, 40 patients experienced a patellar redislocation within 24 months after the primary dislocation, whereas 21 patients, who were assessed after a median follow-up of 37 months (range 24-60 months), had not experienced a subsequent episode of lateral patellar instability. In all patients, age at the time of the primary dislocation, gender, the affected body side, body mass index, bilateral instability, physical activity according to Baecke's questionnaire, the grade of trochlear dysplasia, patellar height, tibial tuberosity-trochlear groove (TT-TG) distance, and patellar tilt were assessed. The odds ratio (OR) of each factor with regard to the patellar redislocation was calculated using contingency tables. Based on these data, a "patellar instability severity score" was calculated.

RESULTS

The patellar instability severity score has six factors: age, bilateral instability, the severity of trochlear dysplasia, patella alta, TT-TG distance, and patellar tilt; the total possible score is seven. Reapplying this score to the study population revealed a median score of 4 points (range 2-7) for those patients with an early episode of patellar redislocation and a median score of 3 points (range 1-6) for those without a redislocation (p=0.0004). The OR for recurrent dislocations was 4.88 (95% CI 1.57-15.17) for the patients who scored 4 or more points when compared with the patients who scored 3 or fewer points (p=0.0064).

CONCLUSION

Based on the individual patient data, the patellar instability severity score allows an initial risk assessment for experiencing a recurrent patellar dislocation and might help differentiate between responders and non-responders to conservative treatment after primary lateral patellar instability.

LEVEL OF EVIDENCE

Case-control study, Level III.

Medial capsule reefing in patellar instability

PURPOSE

The efficacy of medial capsule reefing in the treatment of patellar instability is well documented. Aim of the present study was to prospectively evaluate the outcomes of an all-arthroscopic medial capsule reefing technique in young patients with painful patella syndrome and potential patellar instability.

METHODS

Thirty patients with painful patellar syndrome and potential patellar instability having undergone a minimum of 6 months of intensive rehabilitation were enrolled in the present study. All subjects were evaluated with physical examination, clinical and functional outcomes and complete imaging study.

RESULTS

All patients were reviewed at an intermediate follow-up of 72 months. Average Kujala score improved from 72.9±15.0 to 88.4±7.6 (p<0.0001), average Larsen score from 15.0±2.5 to 17.2±2.2 (p<0.002), average Lysholm from 63.8±16.7 to 87.9±11.7 (p<0.0001) and average Fulkerson score from 69.5±21.5 to 90.8±9.8 (p<0.0001). No intraoperative or postoperative complications were recorded. Ninety per cent of patients were very satisfied or satisfied with their functional result. Twenty-eight patients were reviewed at the final follow-up, 120 months after surgery. Average Kujala was 87.7±8.8 (p<0.0001), average Larsen was 16.8±2.7 (p<0.01), average Lysholm was 87.6±14.3 (p<0.0001), and average Fulkerson was 87.2±13.9 (p<0.0001). Almost 86% of patients were very satisfied or satisfied with their result. However, slight deterioration of the outcomes over time was observed.

CONCLUSION

At the final follow-up, the outcomes of all-arthroscopic technique were significantly improved from preoperative values; however, they were slightly inferior at the 72 months follow-up. This slight deterioration of the outcomes may be the consequence of the reduction in physical activities.

LEVEL OF EVIDENCE

Case series, Level IV.

Medial Patellofemoral Ligament Reconstruction for Patellar Dislocation: A Systematic Review

Background:

With improved understanding of the biomechanical importance of the medial patellofemoral ligament (MPFL), its reconstruction for patellar dislocation has become increasingly popular. The aim of this systematic review was to critically determine the effectiveness of MPFL reconstruction for patellar dislocation.

Hypothesis:

MPFL reconstruction for patellar dislocation leads to a low redislocation rate with improved Kujala scores.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A literature search was performed using Embase and Medline (Ovid) databases. Inclusion criteria included first-time and recurrent patellar dislocation, subluxation, or persistent instability with a minimum follow-up of 12 months and documentation of postoperative redislocation rate or Kujala score. The studies were systematically appraised, and a meta-analysis was performed.

Results:

Twenty-two studies were included: 2 randomized controlled trials, 3 parallel case series, and 17 case series. There were a total of 655 knees in the review, with an age range at time of surgery from 11 to 52 years. The pooled postoperative redislocation rate from all 17 case series showed a mean of 2.44%. The pooled preoperative Kujala scores from 12 case series showed a mean of 51.6 (95% CI, 46.71-56.49). The pooled postoperative Kujala scores from 16 case series showed a mean of 87.77 (95% CI, 85.15-90.39).

Conclusion:

Although the studies were of low quality, the meta-analysis of 17 case series shows that MPFL reconstruction for recurrent patellar dislocation results in a significant improvement in Kujala scores, a low redislocation rate, and acceptable complication rate. Randomized trials would be needed to draw influences on the superiority of MPFL reconstruction compared with other treatments.

Patellar instability

Patella instability can cause significant pain and functional limitations. Several factors can predispose to patella instability, such as ligamentous laxity, increased anterior TT-TG distance, patella alta, and trochlear dysplasia. Acquired factors include MPFL injury or abnormal quadriceps function. In many cases, first-time dislocation can successfully be managed with physical therapy and other nonoperative management; however, more than one dislocation significantly increases the chance of recurrence. Surgical management can improve stability, but should be tailored to the injuries and anatomic risk factors for recurrent dislocation. Isolated lateral release is not supported by current literature and increases the risk of iatrogenic medial instability. Medial repair is usually reserved for patients with largely normal anatomy. MPFL reconstruction can successfully stabilize patients with medial soft tissue injury but is a technically demanding procedure with a high complication rate and risks of pain and arthrosis. Tibial tubercle osteotomy can address bony malalignment and also unload certain articular cartilage lesions while improving stability. Trochleoplasty may be indicated in individuals with a severely dysplastic trochlea that cannot otherwise be stabilized. A combination of procedures may be necessary to fully address the multiple factors involved in causing pain, loss of function, and risk of recurrence in patients with patellar instability.

In-game Management of Common Joint Dislocations

Context:

Sideline management of sports-related joint dislocations often places the treating medical professional in a challenging position. These injuries frequently require prompt evaluation, diagnosis, reduction, and postreduction management before they can be evaluated at a medical facility. Our objective is to review the mechanism, evaluation, reduction, and postreduction management of sports-related dislocations to the shoulder, elbow, finger, knee, patella, and ankle joints.

Evidence Acquisition:

A literature review was performed using the PubMed database to evaluate previous and current publications focused on joint dislocations. This review focused on articles published between 1980 and 2013.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

The clinician should weigh the benefits and risks of on-field reduction based on their knowledge of the injury and the presence of associated injuries.

Conclusion:

When properly evaluated and diagnosed, most sports-related dislocations can be reduced and initially managed at the game.

Vastus medialis obliquus muscle morphology in primary and recurrent lateral patellar instability

The morphology of the vastus medialis obliquus (VMO) muscle in the anatomical setting of an unstable patella has not been described. Therefore, the purpose of this study was to investigate the morphological parameters of the VMO muscle that delineate its importance in the maintenance of patellofemoral joint stability. Eighty-two consecutive subjects were prospectively enrolled in this study. The groups were composed of thirty patients with an acute primary patellar dislocation, thirty patients with recurrent patellar dislocation, and twenty-two controls. Groups were adjusted according to sex, age, body mass index, and physical activity. Magnetic resonance imaging was used to measure the VMO cross-sectional area, muscle-fiber angulation, and the craniocaudal extent of the muscle in relation to the patella. No significant difference was found with respect to all measured VMO parameters between primary dislocation, recurrent dislocation, and control subjects with a trend noted for only the VMO cross-sectional area and the VMO muscle-fiber angulation. This finding is notable in that atrophy of the VMO has often been suggested to play an important role in the pathophysiology of an unstable patellofemoral joint.

Surgical versus non-surgical management for primary patellar dislocations: an up-to-date meta-analysis

The aim of this up-to-date meta-analysis was to compare the effects of surgical versus non-surgical treatment of patients following primary patellar dislocation and to provide the best evidence currently available. A comprehensive literature search was conducted using multiple databases, including Medline, Embase, and Cochrane Registry of Clinical Trials. All databases were searched from the earliest records to May 2013. Eligible studies were selected, and data were extracted by two independent investigators. The primary outcome variable was the frequency of recurrent patellar dislocation. The other outcomes included knee function scores, patient-rated outcomes, and radiographic examination. If appropriate, meta-analysis of these variables was performed. Nine independent trials were found to match the inclusion criteria. The pooled results demonstrated that the incidence of recurrent patellar dislocation and Hughston visual analog scale was significantly lower in the surgical treatment group than that in the non-surgical treatment group (P < 0.05). There was no statistically significant difference between the two treatment groups in frequency of subsequent surgical interventions, percentage of excellent or good subjective opinion, Kujala score, pain score on visual analog scale, and severity of patellofemoral joint osteoarthrosis (P > 0.05). This up-to-date meta-analysis indicates that surgical treatment was associated with a lower risk of recurrent patellar dislocation, but a lower Hughston VAS than non-surgical treatment for primary patellar dislocation. More large high-quality trials and further studies are needed to overcome the limitations of small sample sizes, and varieties of different surgical procedures or non-surgical management strategies adopted in the included trials.

Treatment options for patellofemoral instability in sports traumatology

Patellofemoral instability not only involves lateral patellar dislocation, patellar mal-tracking or subluxation but can also cause a limiting disability for sports activities. Its underlying causes are known as morphological anomalies of the patellofemoral joint or the mechanical axis, femorotibial malrotation, variants of the knee extensor apparatus, and ligamentous insufficiencies often accompanied by poor proprioception. Athletes with such predisposing factors are either suffering from unspecific anterior knee pain or from slightly traumatic or recurrent lateral patellar dislocation Treatment options of patellar instability are vast, and need to be tailored individually depending on the athlete’s history, age, complaints and physical demands. Different conservative and surgical treatment options are reviewed and discussed, especially limited expectations after surgery.

The contemporary management of anterior knee pain and patellofemoral instability

In this review the evidence for the management of patients with patellofemoral disorders is presented confined to anterior knee pain and patellar dislocation (excluding patellofemoral arthritis). Patients present along a spectrum of these two problems and are best managed with both problems considered. The key to managing these patients is by improving muscle function, the patient losing weight (if overweight), and judicious use of analgesics if pain is an important feature. Hypermobility syndrome should always be looked for since this is a prognostic indicator for a poor operative outcome. Operations should be reserved for those with correctable anatomical abnormalities that have failed conservative therapy. The current dominant operation is a medial patellofemoral ligament reconstruction.

[Acute osteochondral lesions after patella dislocation]

Acute osteochondral lesions of the knee are injuries often caused by patella dislocations. In cases of negative standard x-rays magnetic resonance imaging (MRI) scans should be used to exclude these injuries, as even large fragments can escape visualization with x-rays. These lesions are strong indications for surgical intervention especially if refixation is considered. The intra-articular defect is visualized using arthroscopy and the dislocated fragment is retrieved entirely. Inspection of the fragment is performed ex situ to determine whether or not refixation should be performed. The refixation technique to be used for lesions in the femoro-patellar joint depends on fragment size and defect site. Current biodegradable implants have demonstrated good clinical results without the need for implant removal. The rehabilitation protocol should be individualized to the patient, size and site of the defect.

Patella instability: building bridges across the ocean a historic review

The diagnosis of and treatment for musculoskeletal disease and injuries have seen an explosion of new knowledge. More precise imaging, correlative injury anatomy, more focused physical examination features, among others, have led this upsurge of current insight. Crucial to this knowledge revolution is the expansion of international knowledge, which is aided by an adoption of a universal scientific language, electronic transfer of information, and personal communication of surgeons and scientists across national boundaries. One area where this is particularly evident is in our knowledge and treatment for patellofemoral disorders. This article will review the developments in the management of patellar dislocations by tracing their historical roots. This is not meant to be a comprehensive review, but rather to give current readers a "historical memory" upon which to judge and interpret our present-day bridge of knowledge. Level of evidence V.

Patellar dislocation: cylinder cast, splint or brace? An evidence-based review of the literature

Patellar dislocations are a common injury in the emergency department. The conservative management consists of immobilisation with a cylinder cast, posterior splint or removable knee brace. No consensus seems to exist on the most appropriate means of conservative treatment or the duration of immobilisation. Therefore the aims of this review were first to examine whether immobilisation with a cylinder cast causes less redislocation and joint movement restriction than a knee brace or posterior splint and second to compare the redislocation rates after conservative treatment with surgical treatment. A systematic search of Pubmed, Embase and the Cochrane Library was performed. We identified 470 articles. After applying the exclusion and inclusion criteria, only one relevant study comparing conservative treatment with a cylinder cast, brace and posterior splint remained (Mäenpää et al.). In this study, the redislocation frequency per follow-up year was significant higher in the brace group (0.29; p < 0.05) than in the cylinder cast group (0.12) and the posterior splint group (0.08). The proportion of loss of flexion and extension was the highest in the cylinder cast group and the lowest in the posterior splint group (not significant). The evidence level remained low because of the small study population, difference in duration of immobilisation between groups and use of old braces. Also, 12 studies comparing surgical with conservative treatment were assessed. Only one study reported significantly different redislocation rates after surgical treatment. In conclusion, a posterior splint might be the best therapeutic option because of the low redislocation rates and knee joint restrictions. However, this recommendation is based on only one study with significant limitations. Further investigation with modern braces and standardisation of immobilisation time is needed to find the most appropriate conservative treatment for patellar luxation. Furthermore, there is insufficient evidence to confirm the added value of surgical management.

The operative management of patella malalignment

Management of patellofemoral joint pathology is challenging as a result of the unique and complex organization of static forces and dynamic factors contributing to its functional capacity. Anterior knee pain is a common musculoskeletal complaint seen daily in the practices of primary care physicians, rheumatologists, and orthopedic surgeons. The key to successful treatment lies not only in the correct diagnosis of a chondral defect, but more importantly, in the accurate identification of associated pathomechanical factors. Appreciating the pathoanatomic basis of the disease and addressing imbalances and anatomical abnormalities should guide treatment.Despite the complexity of the interplay of various components it is essential to attempt to describe patellar malalignement as a clinical entity in order to proceed with appropriate surgical management and successful outcomes. The goals of patellofemoral re- alignment surgery should be to create both a stable environment for optimal extensor mechanism performance and an appropriate load transmission for optimal cartilage wear and joint loading. In the context of this article we will review the operative management of patellofemoral malalignment; the indications for surgery, the different techniques available and the evidence regarding their effectiveness.A large number of procedures have been employed and they have all undergone various modifications over the course of the years. The majority of publications are retrospective series in poorly defined population groups. There are significant methodological inconsistencies and as a result there is lack of strong evidence base for the majority of these procedures.

[Evidence-based treatment protocol to manage patellar dislocation]

Patellar dislocation is a common knee injury with mainly lateral dislocations, leading to ruptures of the medial patellofemoral ligament in most of the cases. Reliable data and prognostic factors for stability of the patellofemoral joint and satisfaction of the patient after either conservative or operative treatment have not been established yet. Until now, there are no randomized controlled trials for recurrent patellar dislocation at all. As a synopsis of the randomized controlled trials about first-time patellar dislocation, no significant difference between operative and conservative management is evident. This applies to both children and adolescents as well as to adults. There is a clear tendency towards first-line conservative therapy after traumatic patellar dislocation. Operative treatment is only required in case of accompanying injuries like osteochondral fractures or in case of recurrent dislocations. Further prospective randomized controlled trials with standardized operative and conservative treatment and patient cohorts of sufficient size are necessary in the future.