Clinical Outcomes After the Nonoperative Management of Lateral Patellar Dislocations: A Systematic Review

Medial patellofemoral ligament injury. Location-based rate of recurrent patellar dislocation after non-operative treatment

OBJECTIVES

The role of the medial patellofemoral ligament (MPFL) as a patellofemoral joint stabilizing structure is undisputable. After traumatic patellar dislocation, MPFL injury, together with bone edema in the medial patellar facet and lateral femoral condyle, is a pathognomonic finding in magnetic resonance imaging (MRI). MPFL injury in the femoral insertion has been reported to most likely predict recurrent dislocations. The objective of this study was to detect if any MPFL injury location predicts the earliest onset of the patellar re-dislocation.

METHODS

In total, 64 eligible patients with a first-time traumatic patellar dislocation were recruited to the trial. The diagnosis was confirmed within 3 weeks with 3T magnetic resonance imaging. The location of the MPFL injury in MRI was localized at the patellar insertion, midsubstance area, femoral insertion, or a combination of these. During the three-year follow-up period, patellar re-dislocations, range of motion, quadriceps muscle atrophy, and daily symptoms were determined. All the patients were treated non-operatively.

RESULTS

Out of 64 patients, 33 (51.6%) had at least one episode of patellar re-dislocation. Re-dislocations occurred in 8 out of 25 (32.0%) patients with the main injury at the femoral insertion, 5 out of 15 (33.3%) patients with the main injury at the midsubstance area, and 10 out of 24 (41.7%) patients with the main injury at the patellar insertion during the 36 months follow-up (p ​= ​0.758). According to Kaplan-Meier analysis, the location of MPFL injury did not have any statistically significant effect on the timing of re-dislocations. At 36 months, survival of patients with MPFL injury at the patellar insertion was 70.8%, which was not statistically significantly different than the survival in patients with injury at the femoral insertion (88.0%) or at the midsubstance area (93.3%). No differences between single and multiple MPFL injuries were found. At 4 weeks, the range of motion was more restricted in patients with MPFL injury at the femoral insertion (93.4° vs. 108.0° for injury at the midsubstance area and 107.7° at the patellar insertion).

CONCLUSION

The location of MPFL injury did not have any statistically significant effect on timing or the rate of re-dislocations. The MPFL injury at the femoral insertion predicts decreased range of motion (ROM) of the knee and increased quadriceps muscle atrophy during the first three months after sustaining injury.

LEVEL OF EVIDENCE

Level III.

Is There a Strength Deficit of the Quadriceps Femoris Muscle in Patients Treated Conservatively or Surgically after Primary or Recurrent Patellar Dislocations? A Systematic Review and Meta-Analysis

Background: Patellar dislocation is a knee injury affecting generally young, active individuals, damaging joint ligaments and structures, and impacting sports activity and quality of life. Objective: This review aimed to evaluate the role of the quadriceps femoris muscle in knee extension and to consider whether extensor strength deficits are present in patients who have suffered from a primary or recurrent patellar dislocation and have been treated surgically or conservatively. Methods: This systematic literature review with meta-analysis was performed following the PRISMA Statement criteria. The search engines consulted to select studies were MEDLINE/PubMed, Scopus, and Web of Science/ISI. The JBI Critical Appraisal Checklist tools were applied for the quality assessment based on the specific study design. The outcomes were measurements of the knee extension force of the quadriceps femoris muscle, which were objectively quantifiable with an isokinetic or mobile dynamometer. Results: Of the 891 articles initially identified through the databases, 10 studies with a total of 370 patients were included in the analysis. The results indicated a strength deficit of the quadriceps in patients who had undergone a patellar dislocation, in comparison with the control group, when examining the uninvolved limb or in comparison with the pre-operative values. The overall effect size was large, with a value of -0.99. Conclusions: Our review concluded that after a primary or recurrent patellar dislocation, strength deficits of the quadriceps femoris muscle in the knee extension of the affected limb are frequently observed in surgically or conservatively treated patients. This deficit may persist even after a protracted follow-up of up to three years after injury.

Patellofemoral Disorders in Soccer Players

Patellofemoral disorders are common in the world of soccer and impact players across all levels and ages of the sport. Patellofemoral disorders encompass a spectrum of conditions, from anterior knee pain to patellar instability, and are often influenced by complex biomechanical factors and anatomic variations that can predispose to these conditions. In recent years, there has been a growing emphasis on injury prevention strategies and data-driven approaches, championed by organizations like the Union of European Football Associations and individual professional clubs. Conservative management remains the initial approach for many players, including physical therapy and supportive devices. However, surgical intervention, particularly in cases of recurrent patellar dislocations, is often necessary. The understanding of patellofemoral biomechanics in soccer continues to evolve and offers opportunities for more effective injury prevention and tailored treatment strategies. Despite the challenges, a comprehensive approach to patellofemoral disorders in soccer is essential to preserve player health, enhance performance, and sustain the sport's vitality.

Recurrent patellar dislocation: personalised therapy or operative treatment? The REPPORT randomised trial protocol

INTRODUCTION

Recurrent patellar dislocation is a debilitating musculoskeletal condition, affecting mainly adolescents and adults under the age of 30. It can persist for many decades, causing pain and cartilage and soft-tissue damage, potentially leading to osteoarthritis. Recurrent patellar dislocation can be managed with physiotherapy or surgery. However, it is not known which treatment is most effective.

METHODS AND ANALYSIS

Recurrent Patellar Dislocation: Personalised Therapy or Operative Treatment (REPPORT) is a pragmatic, multicentre, two-arm, superiority, randomised controlled trial. It will compare the clinical and cost-effectiveness of an initial management strategy of personalised, phased and progressive rehabilitation, termed personalised knee therapy versus surgery for recurrent patellar dislocation.The trial's target sample size is 276 participants who will be recruited from approximately 20 sites across the UK. Participants will be randomly allocated to the two treatment groups via a central computer-based minimisation system. Treatment allocation will be in a 1:1 ratio, stratified by age, presence of patella alta and recruitment site.The primary outcome is participant-reported function using the Knee injury and Osteoarthritis Outcome 4-domain score at 18 months post randomisation. Health economic evaluation will be conducted from a healthcare system and personal social services perspective. Secondary outcome data including patellar instability, health utility, work/education status, satisfaction with social roles and treatment, health resource use and adverse events will be collected at 6, 12, 18 and 24 months. Analysis will be on an intention-to-treat basis and reported in-line with the Consolidated Standards of Reporting Trials statement.

ETHICS AND DISSEMINATION

The trial was approved by the East Midlands-Nottingham 2 Research Ethics Committee on 30 March 2023.Results will be disseminated via peer-reviewed publications, presentations at national and international conferences, in lay summaries, and using the REPPORT website and social media channels.

TRIAL REGISTRATION NUMBER

ISRCTN17972668.

[Patellofemoral instability in children and adolescents]

Patellofemoral instability is a common and clinically relevant disorder of multifactorial causes. Several concomitant problems such as genua valga, hyperlaxity, injuries or sports-related overuse may contribute to the development of instability and recurrent patellar dislocations. A thorough diagnosis is of paramount importance to delineate every contributing factor. This includes radiographic modalities and advanced imaging such as magnetic resonance imaging or torsional analyses. The authors recommend non-operative management (including physiotherapy, gait and proprioceptive training, orthoses) and, whenever non-operative measures fail, surgical patellar stabilization using, e.g. MPFL reconstruction.

Combined Hip and Knee Strengthening Compared With Knee Strengthening for Individuals With Lateral Patellar Dislocation: A Single-blind, Superiority, Randomized Controlled Trial

Objective

To investigate whether a combined hip and knee muscle strengthening program is superior to a knee strengthening program for people after lateral patellar dislocation (LPD).

Design

Single-blind, superiority, randomized controlled trial with 48 weeks follow-up.

Setting

Physiotherapy out-patient clinic.

Participants

Forty individuals aged 16 or older, with a history of non-traumatic LPD were randomized to a knee-based strengthening (KBSG) or quadriceps and hip strengthening exercise (HQSG) program (N=40). Inclusion criteria included a positive apprehension sign, pain on palpation along the medial retinaculum, and J sign. Exclusion criteria included restricted range of motion (<90° knee flexion), and traumatic or postsurgical LPD.

Interventions

Concealed randomization was performed using random permuted blocks of size 4. Individuals received their corresponding exercise program according to randomization and group allocation: knee-based strengthening (n=20) or combined hip and quadriceps strengthening (n=20) twice weekly for 8 weeks over 16 appointments.

Main Outcome Measures

Primary outcome was the Lysholm Knee Score. Secondary outcomes included Numerical Pain Ratings Scale (NPRS) at rest and during effort, Norwich Patellar Instability Score (NPIS), Kujala Anterior Knee Pain Scale (AKPS), Lower Extremity Functional Scale (LEFS), 4 domains of the WHOQOL-Bref, and recurrence rate. Patient-reported outcome measures were assessed from the baseline to 48 weeks. Assessments were performed by a physiotherapist who was blinded to the group allocation. Data were analyzed by using a repeated-measures ANOVA model with Tukey's post hoc test after an intention-to-treat principle.

Results

At the primary time-point of 8 weeks, there were no substantial between-group differences in the Lysholm Knee Score: mean difference=-6.8 (95% CI -14.3 to 3.7); NPIS: mean difference=23.5 (95% CI 5.6 to 41.3); AKPS: mean difference=-1.54 (95% CI -8.6 to 5.6), NPRS at rest and during effort (mean difference=0.32 (95% CI -0.37 to 1); and mean difference=0.68 (95% CI -0.9 to 1.86); LEFS mean difference=-1.08 (95% CI -5.9 to 2.4), WHOQOL-Bref domains (physical health: mean difference=-0.12, (95% CI -1.26 to 1.02); psychological: mean difference=-0.32 (95% CI -2.04 to 1.4); social relations: mean difference=-0.7 (95% CI -2.2 to 0.82); environment: mean difference=0.44 (95% CI -1 to 1.9), and recurrence rate (P=.69).

Conclusion

This study indicates that combined hip and knee muscle strengthening is not superior to knee-based strengthening for LPD treatment. The limitations stemming from the underpowered nature of the trial must be acknowledged, concerning the potential oversight of moderate intervention effects.

The influence of directional preference on lateral patellar dislocation: a case report

BACKGROUND

There is little consensus on the conservative management of lateral patellar dislocations (LPD). Mechanical diagnosis and therapy (MDT) is an established classification system in the spinal and extremity population. This case report describes the use of MDT in the management and classification of a patient with LPD.

CASE DESCRIPTION

The patient was a 20-year-old female with a 3-month history of left knee pain precipitated by a lateral patellar dislocation. The patient described pain and a feeling of instability with standing and walking and limitations in work and recreational activities which involve lifting, squatting, and running. Based on the patient's response to repeated end range knee movements, the patient was found to have a directional preference (DP) for knee extension and instruction in performance of knee extension DP exercises was provided.

OUTCOMES

The patient's knee examination and subsequent intervention included her responses to repeated end range knee movements. Her knee pain was abolished, and strength, function, and motion were fully restored in five visits. A minimal clinically important difference (MCID) was achieved on the Lower Extremity Functional Scale (LEFS). At discharge, the patient was able to independently manage symptoms and perform all work and recreational activities at a pre-injury level and these improvements were maintained at a 9-month follow-up.

DISCUSSION

There are various management strategies for lateral patellar dislocation. This case demonstrated the use of classifying, subgrouping, and treating a patient with lateral patellar dislocation using the principle of DP.

CONCLUSION

The patient's outcomes suggest that MDT may be used in the nonoperative management of people with LPD who present with a DP.

Recurrence and return to duty following patellar instability events in military personnel

INTRODUCTION

Military service members experience patellar dislocations at a rate 10 times that of civilians. The purpose of this study was to determine the return to duty rate of active duty military personnel following first-time or recurrent patellar dislocation. Secondary goals were to identify patient variables and radiographic parameters associated with recurrent instability and requiring medical separation from military service.

METHODS

The Military Health System Data Repository was used to identify all active-duty military personnel who sustained a patellar dislocation between 2013 and 2018. Medical records were searched for patient variables including demographics, clinical findings, radiographic findings, treatment, adverse outcomes and military disposition. Patient variables associated with recurrent instability and undergoing medical separation were determined using univariate analysis and multivariate logistic regression. A total of 207 patients met inclusion and exclusion criteria.

RESULTS

Following patellar instability event, 30% of the cohort underwent surgical treatment. Fourteen per cent (29 of 207) underwent medical separation from military service. Regardless of treatment, 9% (18 of 207) experienced recurrent dislocation and 3% (6 of 207) experienced recurrent instability without dislocation. On multivariate analysis, none of the studied patient variables were associated with recurrent instability or medical separation.

CONCLUSIONS

Among military personnel, return to duty rates are similar to return to sport rates in civilians. This study demonstrates no difference in risk of recurrent instability or medical separation based on anatomical factors, which is useful during shared decision-making regarding treatment options and goals.

Surgeon and physiotherapist approaches to operative or non-operative management of people with recurrent patellar dislocation: A case-based UK survey

BACKGROUND

Physiotherapists are often key decision-makers on when to refer patients with recurrent patellar dislocation for surgical opinion. Limited guidance exists to aid this decision. Differences in orthopaedic surgeons' and physiotherapists' views on which patients and when to refer people for surgical consideration or non-operative care may affect outcome. This study aimed to explore orthopaedic surgeons and physiotherapists decision-making surrounding treatment opinions for patients with recurrent patellar dislocation.

METHODS

An online survey performed. UK registered and practicing orthopaedic surgeons and physiotherapists were invited to participate. The survey utilised two vignettes and a series of related questions to ascertain respondents' views on decision-making to surgical referral for people with recurrent patellar dislocation. Data were analysed using descriptive statistics and inferential statistical tests to explore factors related to responses.

RESULTS

Eighty four respondent surveys were analysed (38 surgeons, 46 physiotherapists). Overall, there was a low level of agreement amongst respondents for the management of the vignettes (k = 0.215, p = < 0.0005). Some disparity existed between the professions on the definition of recurrent patellar dislocations and the clinical features which may require an early surgical assessment. Physiotherapists were three times more likely to delay a surgical opinion for the vignettes presented in this study than the surgeons.

CONCLUSION

This is the first study to investigate orthopaedic surgeons' and physiotherapists' views on decision-making around surgical or non-operative management for recurrent patellar dislocations. High-quality research is required to underpin explicit guidance on decision-making regarding management of recurrent patellar dislocation.

Conservative management following patellar dislocation: a level I systematic review

BACKGROUND

Patellar instability is a common and disabling clinical condition. Treatment of acute primary patellar dislocation aims to reduce the risk of recurrence or painful subluxation and improve function. However, the actual clinical efficacy of any management modality following an acute dislocation has never been demonstrated in prospective or retrospective studies, and the optimal way in which the various management modalities should be used is at best unclear.

METHODS

A search was conducted in PubMed, Bireme and Embase databases. Inclusion criteria followed the acronym PICOS, (P) subjects with patellar instability, (I) therapeutic interventions, (C) placebo or control or surgical treatments, (O) rate of dislocations and function, and (S) clinical trials. The Medical Subject Headings (MeSH) terms used were: (("patellar instability") OR ("patellar dislocation")) AND ((physiotherapy) OR (rehabilitation) OR ("conservative treatment") OR (therapy) OR (therapeutic)). The risk of bias was analysed using the PeDRO scale.

RESULTS

Seven randomized controlled trials including 282 patients were considered. The quality of studies detailing the results of conservative treatment was higher than that of surgical procedures, but all studies have relatively low methodological quality. Four studies compared physiotherapeutic interventions with surgical procedures, and three studies compared conservative intervention techniques.

CONCLUSION

An unstructured lower limb physical therapy programme evidences similar outcomes to specific exercises. Surgical management is associated with a lower rate of re-dislocation; however, whether surgery produces greater functional outcomes than conservative management is still unclear. The use of a knee brace with a limited range of motion, stretching and neuromuscular exercises are the most commonly recommended physiotherapy methodologies.

Current concepts in the treatment of first-time patella dislocation in children and adolescents

Background

Lateral dislocation of the patella is a common injury in children. It can occur in previously healthy and anatomically normal knees, but there are several abnormalities that predispose to patellar instability. Magnetic resonance imaging is an essential part of assessing for associated injuries and risk of further instability. Treatment aims to prevent redislocation, residual instability, osteoarthritis, and allow return to previous activities. The purpose of this review was to assess evidence for management of first-time patella dislocation in children and adolescents.

Methods

Literature review was performed, accompanied by the current best practice by the authors.

Results

Non-operative treatment is preferred, except where there are associated injuries such as osteochondral fractures that would benefit from surgery. The exact method of ideal non-operative management is not clearly defined but should focus on restoration of range of movement and strength with bracing as indicated. There seems to be a trend toward operative intervention that may well be inappropriate.

Conclusion

Further prospective studies are required with focus on the younger patient to fully understand if there is an at-risk group that would benefit from early surgery.

Level of evidence

level III.

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.

Surgical strategies for chondral defects of the patellofemoral joint: a systematic review

BACKGROUND

The management of chondral defects of the patellofemoral joint is debated, and definitive evidence is lacking. This study systematically updated and summarised the current literature on the surgical management of isolated chondral defects of the patellofemoral joint, discussing techniques, outcome, pitfalls, and new frontiers.

METHODS

This systematic review was conducted according to the 2020 PRISMA statement. In August 2022, PubMed, Web of Science, Google Scholar, and Embase databases were accessed with no time constrain. All the clinical studies investigating the surgical management of chondral defects of the patellofemoral joint were retrieved. Articles which reported data on patients with advanced to severe osteoarthritis were not eligible. Only studies with a minimum 24 months follow-up were considered. Studies which mixed results of patellofemoral and tibiofemoral joints were not considered.

RESULTS

Data from 10 studies (692 procedures) were retrieved. The mean follow-up was 46.9 ± 18.2 months. The mean age of the patients was 34.0 ± 6.1 years, and the mean BMI was 25.9 ± 0.8 kg/m². The mean duration of symptoms before the index surgery was 81.0 ± 24.0 months. The mean defect size was 3.8 ± 0.8 cm². All the PROMs improved from baseline to last follow-up: VAS 0-10 (P = 0.04), Tegner (P = 0.02), Lysholm (P = 0.03), and International Knee Documentation Committee (P = 0.03). The rate of hypertrophy was 5.6% (14 of 251), the rate of progression to total knee arthroplasty was 2.4% (2 of 83), the rate of revision was 16.9% (29 of 136), and the rate of failure was 13.0% (16 of 123).

CONCLUSION

Current surgical strategies may be effective to improve symptoms deriving from chondral defects of the patellofemoral joint. The limited and heterogeneous data included for analysis impact negatively the results of the present study. Further clinical studies are strongly required to define surgical indications and outcomes, and the most suitable technique.

High Rates of Damage to the Medial Patellofemoral Ligament, Lateral Trochlea, and Patellar Crest After Acute Patellar Dislocation: Magnetic Resonance Imaging Analysis

PURPOSE

The primary outcome of interest of this study was to determine the frequency, location, and extent of chondral injuries and medial patellofemoral ligament (MPFL) tears, along with the rate of loose bodies, in the knee after acute primary patellar dislocation. The secondary outcome of interest was to conduct a multivariate analysis to investigate whether the presence of pathoanatomic abnormalities, including structural differences in the knees of the patients, is associated with the features of the lesions.

METHODS

Patients who underwent magnetic resonance imaging after primary acute patellar dislocation were identified from our institutional databases. We analyzed a total of 175 magnetic resonance imaging scans of patients aged between 14 and 25 years who were eligible for inclusion.

RESULTS

Chondral damage to the medial facet of the patella was present in 36 patients; patellar crest, 78 patients; and lateral patellar facet, 28 patients. One patient presented with chondral defects in the medial trochlear facet, whereas 118 patients showed chondral defects in the lateral trochlear facet. Loose bodies were present in 142 patients. A total of 161 patients (92%) showed MPFL damage. The patellar portion was affected in 119 patients. Of the patients, 28 showed a partially damaged MPFL (<50%), 42 showed MPFL damage greater than 50%, and 49 presented with a complete tear of the MPFL. MPFL lesions were observed on the femoral side in 42 patients. Fourteen patients presented with an avulsion fracture on the patellar side; 28 patients, on the femoral side.

CONCLUSIONS

The MPFL was injured in 92% of 175 patients after a first-time acute patellar dislocation. Chondral damage was most frequent at the patellar crest, followed by the lateral femoral epicondyle. No association was found between patella alta, the sulcus angle, the Q angle, the tibial tubercle-trochlear groove distance, trochlear and patellar dysplasia, and soft-tissue damage.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

Dynamic versus static medial patellofemoral ligament reconstruction technique in the treatment of recurrent patellar dislocation: a randomized clinical trial protocol

BACKGROUND

The redislocation rate of conservatively treated patella instability is high. One of the leading surgical strategies is medial patellofemoral ligament reconstruction. Over-tensioning is one of the most challenging complications in static medial patellofemoral ligament reconstruction as the graft used for reconstruction is isometric and the anatomical MPFL is a mostly dynamic structure. As an alternative to established static reconstruction techniques, dynamic graft techniques have been introduced for stabilizing the patella with the aim of providing a more physiological reconstruction of the medial patellofemoral ligament. To date, data on clinical outcomes are scarce and on biomechanical outcomes of the dynamic MPFL reconstruction are lacking. Here, we present the protocol of a randomized clinical trial for comparing clinical and biomechanical outcomes of dynamic versus static medial patellofemoral ligament reconstruction.

METHODS

This study is a prospective, single blinded, randomized, multicenter, multimodal (clinical and biomechanical) clinical trial. Patients with recurrent patella dislocation requiring isolated MPFL reconstruction will be recruited and randomized to the dynamic or static reconstruction technique. Participants will be followed up for 2 years with a total of five follow-ups. Preoperative magnetic resonance imaging, upright radiographs, surgical reports and patient records will be evaluated, and clinical and functional outcomes will be measured. Patient-reported knee function and anterior knee pain as assessed with the Kujala score will serve as primary outcome. For biomechanical outcome, pre- and postoperative evaluations will be performed to assess isokinetic muscle strength, gait asymmetry, joint kinematics and kinetics, and timing of muscle activity.

DISCUSSION

The results of the study will clarify whether the reported surgery success for patella stabilization via dynamic MPFL reconstruction is due to muscle contraction or to the passive tenodesis effect combined with clinical outcome measures. With this study, we will provide much needed information on knee biomechanics after dynamic versus static MPFL reconstruction to provide evidence to support orthopedic surgeons in evidence-based decision-making in their quest for surgical techniques most favorable for their patients. Trial registration The study protocol was registered at clinicaltrials.gov (NCT04849130). Registered 19 April 2021, https://clinicaltrials.gov/ct2/show/NCT04849130 .

Mental and physical health-related quality of life in patients with recurrent patellar dislocations-a generic and disease-specific quality of life questionnaire assessment

Purpose

There is a paucity of quality of life (QoL) assessments in studies evaluating patients treated for recurrent lateral patellar dislocation (LPD). The primary aim of this study was to investigate whether mental well-being is impaired in patients with chronic (recurrent) LPD and, if so, to assess whether the mental health-related QoL dimension improves equivalently to the physical-related QoL dimension after successful surgical treatment.

Methods

Thirty-eight patients with recurrent LPD over a mean course of the disease of 4.7 ± 3.9 years (1—18 years) prior to surgery were included. Generic health-related QoL (HRQoL) (Short Form 36; SF-36) and disease-specific QoL (Banff Patella Instability Instrument 2.0; BPII 2.0) were assessed preoperatively and after a mean follow-up of 3.5 ± 0.8 years (2 – 5 years) postoperatively.

Results

Untreated LPD significantly impacted the physical dimension of patients’ generic HRQoL and their disease-specific QoL. When compared to age-equivalent normative data sets, the mental HRQoL dimension was not reduced prior to operative treatment but increased during the follow-up period. Surgical treatment normalized the physical dimension of patients’ generic HRQoL and significantly improved their disease-specific QoL. However, BPII 2.0 values remained reduced, albeit patellae were successfully stabilized.

Conclusion

The results of this study indicate that patients with recurrent LPD are generally in good mental health, although physical impairment is striking. Notwithstanding that surgery prevented further dislocations and normalized the generic HRQoL, the disease-specific QoL remained reduced as far as this can be interpreted without population-based data.

Level of evidence

Level IV; Retrospective case series.

Protocols of rehabilitation and return to sport, and clinical outcomes after medial patellofemoral ligament reconstruction with and without tibial tuberosity osteotomy: a systematic review

PURPOSE

No consensus exists on rehabilitation programmes after medial patellofemoral ligament reconstruction (MPFLR) with or without tibial tuberosity osteotomy (TTO). This systematic review examined the content and timeline of rehabilitation (weightbearing, range of motion [ROM] and exercise therapy) and return to sport (RTS), as well as patient-reported outcomes after MPFLR with or without TTO.

METHODS

The PubMed, Cochrane Library, Web of Sciences, CINAHL and SPORTDiscus databases were searched from inception to December 2021. Studies that reported postoperative rehabilitation programmes and patient-reported outcomes for patients aged ≥ 18 years who underwent MPFLR with or without concomitant TTO were included.

RESULTS

Eighty-five studies were included, 57 of which were case series and only one randomised controlled trial on rehabilitation programmes. Non-weightbearing was set within one week post-operatively in approximately 80% of weightbearing programmes for MPFLR without and with TTO. Joint immobilisation was set within one week post-operatively in 65.3% and 93.8% of programmes for MPFLR without and with TTO, respectively. Weightbearing and ROM (≤ 90°) restriction were within three weeks post-operatively for > 50% of the programmes. Quadriceps strengthening was the most cited exercise therapy (33 programmes), most often initiated within two weeks post-operatively. However, few other exercise programmes were cited (only nine programmes). RTS was mostly noted at six months post-operatively (35 programmes). The weighted mean Kujala score was 87.4 points.

CONCLUSION

Regardless of TTO addition to MPFLR, most studies restricted weightbearing and ROM only in the early post-operative period, with seemingly favourable clinical results. Limited information was available on post-operative exercise therapy.

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).

Patellofemoral Instability in Children: Imaging Findings and Therapeutic Approaches

Patellofemoral instability (PFI) is common in pediatric knee injuries. PFI results from loss of balance in the dynamic relationship of the patella in the femoral trochlear groove. Patellar lateral dislocation, which is at the extreme of the PFI, results from medial stabilizer injury and leads to the patella hitting the lateral femoral condyle. Multiple contributing factors to PFI have been described, including anatomical variants and altered biomechanics. Femoral condyle dysplasia is a major risk factor for PFI. Medial stabilizer injury contributes to PFI by creating an imbalance in dynamic vectors of the patella. Increased Q angle, femoral anteversion, and lateral insertion of the patellar tendon are additional contributing factors that affect dynamic vectors on the patella. An imbalance in the dynamics results in patellofemoral malalignment, which can be recognized by the presence of patella alta, patellar lateral tilt, and lateral subluxation. Dynamic cross-sectional images are useful for in vivo tracking of the patella in patients with PFI. Therapeutic approaches aim to restore normal patellofemoral dynamics and prevent persistent PFI. In this article, the imaging findings of PFI, including risk factors and characteristic findings of acute lateral patellar dislocation, are reviewed. Non-surgical and surgical approaches to PFI in pediatric patients are discussed.

Lateral Patellar Dislocation: A Critical Review and Update of Evidence-Based Rehabilitation Practice Guidelines and Expected Outcomes

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Nonoperative treatment of a lateral patellar dislocation produces favorable functional results, but as high as 35% of individuals experience recurrent dislocations.

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Medial patellofemoral ligament reconstruction is an effective treatment to prevent recurrent dislocations and yield excellent outcomes with a high rate of return to sport.

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Both nonoperative and postoperative rehabilitation should center on resolving pain and edema, restoring motion, and incorporating isolated and multijoint progressive strengthening exercises targeting the hip and knee.

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Prior to return to sports, both functional and isolated knee strength measurements should be used to determine leg symmetry strength and to utilize patient-reported outcome measures to assess the patient's perceived physical abilities and patellofemoral joint stability.

Paediatric injuries around the knee: Soft tissue injuries

We review the diagnosis, management and potential pitfalls of acute soft tissue injuries in the skeletally immature knee, including anterior cruciate ligament (ACL) injuries, meniscal injuries, patellar dislocation and patellofemoral instability (PFI). There has been an increasing incidence of such injuries in the paediatric population, and controversy remains regarding their treatment. We summarise evidence-based treatments for these injuries and discuss strategies to minimise complications as the child reaches skeletal maturity.

Blood flow Restriction training After patellar INStability (BRAINS Trial)

Background

Patellar instability is a common and understudied condition that disproportionally affects athletes and military personnel. The rate of post-traumatic osteoarthritis that develops following a patellar dislocation can be up to 50% of individuals 5–15 years after injury. Conservative treatment is the standard of care for patellar instability however, there are no evidence-informed rehabilitation guidelines in the scientific literature. The purpose of this study is to assess the effectiveness of blood-flow restriction training (BFRT) for patellar instability. Our hypotheses are that this strategy will improve patient-reported outcomes and accelerate restoration of symmetric strength and knee biomechanics necessary to safely return to activity.

Methods/design

This is a parallel-group, superiority, randomized, double-blinded, placebo-controlled clinical trial at the University of Kentucky, sports medicine clinic that aims to recruit 78 patients with acute patellar dislocations randomly allocated into two groups: (1) sham BFRT and (2) BFRT. Both groups will receive the current standard of care physical therapy 3 times per week for up to 9 weeks. Physical therapy sessions will consist of typical standard of care treatment followed by BFRT or sham BFRT. Primary outcomes include the Norwich Patellar Instability Scale, quadriceps strength, and imaging and biochemical biomarkers of cartilage degradation.

Discussion

The current standard of care for non-operative treatment of patellar instability is highly variable does not adequately address the mechanisms necessary to restore lower extremity function and protect the long-term health of articular cartilage following injury. This proposed novel intervention strategy uses an easily implementable therapy to evaluate if BFRT significantly improves patient-reported outcomes, function, and joint health over the first year of recovery.

Trial registration

Blood Flow Restriction Training, Aspiration, and Intraarticular Normal Saline (BRAINS) NCT04554212. Registered on 18 September 2020.

[Primary and recurrent patellar dislocation: recommendation for diagnostic evaluation, risk stratification and treatment]

The dogma that (every) primary patellar dislocation should be treated non-operatively is considered outdated. Therefore, every first-time dislocation, as well as every recurrent dislocation, should be fully diagnosed with regard to the injury pattern and anatomically predisposing risk factors. This enables the use of risk stratification models to assess the risk of recurrent episodes of instability, thereby supporting the clinical decision-making process. The reconstruction of the MPFL can be considered an established and successful treatment strategy for patellar instability. However, the additional correction of bony risk factors is often useful. In this context, the preoperative grading of the J sign and dynamic assessment of patellar instability (dynamic apprehension test) are of utmost importance. These findings, combined with the radiographic imaging findings, can be used as a clinical decision aid for a bony correction procedure.

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.

Surgical and Radiological Anatomy of the Medial Patellofemoral Ligament: A Magnetic Resonance Imaging and Cadaveric Study

The purpose of this study was to compare the measurement of several anatomical features of the medial patellofemoral ligament (MPFL) between magnetic resonance imaging (MRI) and by direct fashion during dissection. We hypothesized that the measurements between these two techniques would agree. MRI of 30 fresh-frozen cadaveric knees was followed by dissection. MPFL patella and femoral attachment were evaluated; their shape, length, and width were measured; and measurements were compared. MRI was deemed unreliable for the determination of several of the aforementioned anatomical features. Important findings include: (a) observations on MPFL attachment at medial patella side and attachment to quadriceps were identical between dissection and MRI; (b) average width at patella insertion was significantly different between the two methods (p = 0.002); and (c) an attachment to the quadriceps tendon was present in 20/30 specimens and d. detailed measurements of a thin, non-linear, and three-dimensional structure, such as the MPFL, cannot be performed on MRI, due to technical difficulties. This anatomical radiological study highlights the shape, anatomical measurements (length and width), and attachment of the MPFL using a relatively large cadaveric sample and suggests that MRI is not reliable for detailed imaging of its three-dimensional anatomy.

Is an individually tailored programme of intense leg resistance and dynamic exercise acceptable to adults with an acute lateral patellar dislocation? A feasibility study

Background

Lateral patellar dislocations mainly affect active teenagers and young adults. To help people recover, non-surgical exercise-based treatment is often recommended but the optimal exercise-based treatment is unknown. Currently, treatment outcomes after this injury are variable. Common problems include recurrent dislocation, reduced activity levels, and later surgery. A programme of intense leg resistance exercises, and dynamic exercises related to participants’ activity-related goals, has rationale, but has not been previously reported. In line with the Medical Research Council guidance, this study aimed to assess the acceptability of a novel evidence-based exercise programme for adults after acute lateral patellar dislocation and the feasibility of future research evaluating this treatment.

Methods

A single-group prospective study was conducted at the John Radcliffe Hospital, Oxford, UK. Participants were 16 years or older with an acute first-time or recurrent lateral patellar dislocation. Participants received up to six face-to-face, one-to-one, physiotherapy sessions, over a maximum of 3 months, and performed intensive home exercises independently at least three times per week. Strategies to increase exercise adherence were used. Primary objectives were to determine the number of eligible patients, the recruitment rate (proportion of eligible patients that provided written informed consent), participant adherence to scheduled physiotherapy sessions and self-reported adherence to prescribed exercise, and intervention acceptability to participants measured by attrition and a study-specific questionnaire. Data were analysed using descriptive statistics.

Results

Fifteen of 22 (68%) patients with a lateral patellar dislocation were eligible. All eligible (100%) were recruited. Two of 15 (13%) participants provided no outcome data, 2/15 (13%) provided partial outcome data, and 11/15 (73%) provided all outcome data. Questionnaire responses demonstrated high intervention acceptability to participants. Participants attended 56/66 (85%) physiotherapy sessions and 10/11 (91%) participants reported they ‘always’ or ‘often’ completed the prescribed exercise. One participant redislocated their patella; another experienced knee pain or swelling lasting more than one week after home exercise on three occasions.

Conclusion

The intervention appeared acceptable to adults after acute lateral patellar dislocation, and a future randomised pilot trial is feasible. This future pilot trial should estimate attrition with increased precision over a longer duration and assess participants’ willingness to be randomised to different treatments across multiple centres.

Trial registration

ClinicalTrials.govNCT03798483, registered on January 10, 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00932-x.

Objectively quantified lower limb strength recovery in people treated surgically or non-surgically after patellar dislocation: A systematic review

OBJECTIVE

Synthesize evidence on objectively quantified lower limb strength recovery in people treated surgically or non-surgically after patellar dislocation.

METHODS

MEDLINE, EMBASE, Cochrane Library, SPORTDiscus, PEDro, AMED and CINAHL databases were last searched on July 30th, 2020 for randomized controlled trials and observational studies that objectively quantified lower limb strength in people (any age or sex) treated surgically or non-surgically after patellar dislocation.

RESULTS

24 studies were included (877 participants, median age 20.7). All assessed knee extension strength, 11 knee flexion strength, three hip abduction strength, two hip external rotation strength, and one hip flexion, extension, adduction, and internal rotation strength. One randomized controlled trial judged at high risk of bias and two cohort studies with methodological limitations compared lower limb strength recovery between surgically and non-surgically treated people, with conflicting findings. After surgery, median long-term (>8 months) knee extension strength was 82.5% (IQR 78.5-88.2; 13 studies) of the unaffected leg and knee flexion strength was 91.5% (IQR 90.7-96.9; five studies). After non-surgical treatment, median long-term knee extension strength was 86% (IQR 79.3-87.4; four studies) and mean flexion strength ranged from 95.2 to 96.7% (two studies). Mean hip strength was always >90% (two studies). Two redislocations during eccentric isokinetic knee testing and knee pain during isokinetic knee extension testing were reported as adverse events.

CONCLUSIONS

Available evidence indicates that after patellar dislocation, knee extension strength deficits in the affected limb are frequently observed and can persist long term, but this remains uncertain due to the limitations of relevant included studies. Whether lower limb strength recovery differs between people treated surgically and those treated non-surgically after patellar dislocation also remains uncertain.

TRIAL REGISTRATION

(PROSPERO CRD42019139533).

Malalignment sign on knee magnetic resonance imaging: a new predictor for excessive femoral anteversion in patients with patellar dislocation

PURPOSE

To evaluate the clinical relevance of the newly identified malalignment sign in predicting excessive femoral anteversion in patients with patellar dislocations.

METHODS

A total of 55 patients with patellar dislocation who underwent surgical treatment between 2016 and 2019 were included in this study. Femoral anteversion, tibial torsion, and the femorotibial index were measured via a CT scan. The malalignment sign on the knee MRI was defined as a malalignment between the lateral side of the intercondylar fossa of the femur and the lateral intercondylar eminence of the tibial plateau.

RESULTS

A positive malalignment sign was observed in 36 of the 55 patients. Increased femoral anteversion was significantly correlated with the number of frames with a positive malalignment sign (r = 0.511, P < 0.001). The value of femoral anteversion was significantly greater in the group with a positive malalignment sign (P = 0.02). For a femoral anteversion value of 32°, the sensitivity and specificity of the malalignment sign reached the maximal level of 89.5% and 47.2%, respectively.

CONCLUSION

Increased femoral anteversion correlated significantly with a positive malalignment sign on knee MRI. However, tibial torsion did not affect the malalignment sign. A positive malalignment sign is evidence for femoral derotation osteotomy.

LEVEL OF EVIDENCE

Level IV.

Predicting Risk of Recurrent Patellofemoral Instability With Measurements of Extensor Mechanism Containment

BACKGROUND

Identifying risk factors for recurrent patellar dislocation after a primary dislocation may help guide initial treatment. Magnetic resonance imaging (MRI) measurements relating the alignment of the extensor mechanism to trochlear morphology have been shown to distinguish patients with dislocations from controls, but their usefulness in predicting the risk of a second dislocation is not known.

PURPOSE

To identify the association of novel MRI measures of patellar containment with recurrent instability in pediatric patients presenting with a first-time patellar dislocation.

STUDY DESIGN

Cohort study (Prognosis); Level of evidence, 3.

METHODS

The study was conducted at a tertiary care children's hospital (2005-2014) on patients (age, 8-19 years) with a first-time patellar dislocation. MRI measurements were made by 2 independent raters. Interobserver reliability was assessed for all measurements via an intraclass correlation coefficient (ICC). Only measurements with an ICC >0.8 were included. Univariable and multivariable logistic regression analyses were used to evaluate variables associated with recurrence.

RESULTS

A total of 165 patients with a median age of 14 years and a slight (57.6%) female predominance was identified. The median follow-up length of the whole cohort was 12.2 months (interquartile range, 1.6-37.1 months). Subsequent instability was documented in 98 patients (59.4%). MRI measurements with excellent correlation (ICC > 0.8) were the tibial tubercle to trochlear groove distance (TT-TG), the tangential axial width of the patella, the tangential axial trochlear width, the axial width of the patellar tendon beyond the lateral trochlear ridge (LTR), and the tibial tubercle to LTR distance. In univariate analysis, all mentioned MRI measurements had significant association with recurrent instability. However, after both backward and forward stepwise regression analyses, the tibial tubercle to LTR distance was the only independent predictor of recurrent instability (P = .003 in both). Patients with a tibial tubercle to LTR distance value greater than -1 mm had a significantly higher rate of recurrent patellar dislocation (72%).

CONCLUSION

Of numerous axial view MRI parameters, only the tibial tubercle to LTR distance demonstrated a statistically significant association with recurrent patellar instability upon multivariable logistic regression analysis during short-term follow-up of a pediatric population presenting with initial lateral patellar dislocation. Interobserver correlation of the tibial tubercle to LTR distance was good (ICC > 0.8) and similar to that of TT-TG.

The feasibility of a randomised control trial to assess physiotherapy against surgery for recurrent patellar instability

Background

Patellar instability is a relatively common condition that leads to disability and restriction of activities. People with recurrent instability may be given the option of physiotherapy or surgery though this is largely driven by clinician preference rather than by a strong evidence base. We sought to determine the feasibility of conducting a definitive trial comparing physiotherapy with surgical treatment for people with recurrent patellar instability.

Methods

This was a pragmatic, open-label, two-arm feasibility randomised control trial (RCT) with an embedded interview component recruiting across three NHS sites comparing surgical treatment to a package of best conservative care; ‘Personalised Knee Therapy’ (PKT). The primary feasibility outcome was the recruitment rate per centre (expected rate 1 to 1.5 participants recruited each month). Secondary outcomes included the rate of follow-up (over 80% expected at 12 months) and a series of participant-reported outcomes taken at 3, 6 and 12 months following randomisation, including the Norwich Patellar Instability Score (NPIS), the Kujala Patellofemoral Disorder Score (KPDS), EuroQol-5D-5L, self-reported global assessment of change, satisfaction at each time point and resources use.

Results

We recruited 19 participants. Of these, 18 participants (95%) were followed-up at 12 months and 1 (5%) withdrew. One centre recruited at just over one case per month, one centre was unable to recruit, and one centre recruited at over one case per month after a change in participant screening approach. Ten participants were allocated into the PKT arm, with nine to the surgical arm. Mean Norwich Patellar Instability Score improved from 40.6 (standard deviation 22.1) to 28.2 (SD 25.4) from baseline to 12 months.

Conclusion

This feasibility trial identified a number of challenges and required a series of changes to ensure adequate recruitment and follow-up. These changes helped achieve a sufficient recruitment and follow-up rate. The revised trial design is feasible to be conducted as a definitive trial to answer this important clinical question for people with chronic patellar instability.

Trial registration

The trial was prospectively registered on the International Standard Randomised Controlled Trial Number registry on the 22/12/2016 (reference number: ISRCTN14950321). http://www.isrctn.com/ISRCTN14950321

Surgical versus conservative treatment for first patellofemoral dislocations: a meta-analysis of clinical trials

INTRODUCTION

The first approach for acute patellar dislocation is still a debated topic. The purpose of the present study was to perform a meta-analysis evaluating the outcomes of the surgical approach compared to the conservative treatments for primary acute patellar dislocation. We hypothesize that a prompt surgical treatment may lead to better outcomes in terms of re-dislocations and quality of life.

METHODS

This meta-analysis was performed according to the PRISMA guidelines. All the prospective clinical trials comparing surgical and conservative treatment for first acute patellofemoral dislocation were included in this study. For the methodological quality assessment, the PEDro appraisal score was adopted. For the risk of publication bias, the funnel plot was performed. The statistical analysis was performed using the Review Manager Software 5.3 (The Nordic Cochrane Collaboration, Copenhagen).

RESULTS

The funnel plot detected a low risk of publication bias. According to the PEDro score, the methodological quality assessment was good. Data from 654 patients were collected, undergoing a mean of 53.8 ± 48.4 month follow-up. A total of 311 patients (17.66 ± 4.1 years old) were analyzed in the surgery group and 291 patients (19.25 ± 4.5 years old) in the conservative ones. The mean Kujala score resulted in greater favor of the surgery group (MD: 9.99%; P = 0.006). The analysis of the comparison of re-dislocations resulted in favor of the surgery group (OR: 0.41; P < 0.0001). The analysis of the comparison of persistent joint instability resulted in favor of the surgery group (OR: 0.41; P < 0.0001).

CONCLUSIONS

Data from the present study encourage a prompt surgical approach for the first patellofemoral dislocation.

Recurrent Patellofemoral Instability in the Pediatric Patient: Management and Pitfalls

PURPOSE OF REVIEW

The purpose of the review is to discuss the relevant pathoanatomy, management, complications, and technical considerations for recurrent patellofemoral instability (PFI) in the pediatric population. Special consideration is given to recent literature and management of the patient with repeat instability following surgery.

RECENT FINDINGS

Patellar stabilization surgery is in principle dependent upon restoration of normal patellofemoral anatomy and dynamic alignment. Historically, treatment options have been numerous and include extensor mechanism realignment, trochleoplasty, and more recently repair and/or reconstruction of the medial patellofemoral ligament (MPFL) as a dynamic check rein during initial knee flexion. In skeletally immature patients, preference is given to physeal-sparing soft tissue procedures. While medial patellofemoral ligament reconstruction has become a popular option, postoperative failure is a persistent issue with rates ranging from 5 to 30% for PFI surgery in general without any single procedure (e.g., distal realignment, MPFL reconstruction) demonstrating clear superiority. Failure of surgical patellar stabilization is broadly believed to occur for three main reasons: (1) technical failure of the primary stabilization method, (2) unaddressed static and dynamic pathoanatomy during the primary stabilization, and (3) intrinsic risk factors (e.g., collagen disorders, ligamentous laxity). PFI is a common orthopedic condition affecting the pediatric and adolescent population. Treatment of repeat instability following surgery in the PFI patient requires understanding and addressing underlying pathoanatomic risk factors as well as risks and reasons for failure.

Management of the first-time lateral patellar dislocation

BACKGROUND

Little guidance exists on the management of the first-time patellar dislocation. The aim of this article was to review current guidance for management of this condition.

METHODS

Recent meta-analyses, systematic reviews and current consensus documents relating to first-time patellar dislocation were sourced. An instructional lecture was then created and delivered at the acute knee injuries session at the British Orthopaedic Association 2019 annual conference, which was presented on behalf of the British Association for Surgery of the Knee. This article has been written based on this lecture.

RESULTS

There is a paucity of literature relating to management of the first-time patellar dislocation. Many studies are of poor design, with inadequate follow-up, making it difficult to draw conclusions from them. However, based upon available information and consensus from working groups it is recommended that patients presenting with first-time dislocation should be assessed to ensure they have not sustained an alternative or associated injury that may require surgical intervention, be assessed and counselled for the risk of recurrent dislocation, and be referred for initial conservative treatment. Surgical stabilisation should be reserved for patients with recurrent instability.

CONCLUSIONS

Most patients with a first-time patellar dislocation can be managed conservatively, having excluded associated injuries. Due to the poor quality of the literature, care must be taken interpreting the results of studies. It is clear that further research is required in this field.

A Meta-analysis of Surgical Versus Nonsurgical Treatment of Primary Patella Dislocation

PURPOSE

To compare outcomes after surgery versus nonsurgical treatment in the management of primary lateral patellar dislocation (LPD) through a meta-analysis of randomized controlled trials (RCTs) in terms of redislocation rate and clinical outcome, investigating both short-term (<6 years) functional recovery and overall benefit over time (>6 years).

METHODS

A systematic search of the literature was performed in November 2018. Risk of bias and quality of evidence were evaluated according to the Cochrane guidelines. RCTs investigating differences between surgery and nonsurgical treatment in primary LPD were included. The outcomes evaluated were redislocation rate, reinterventions, and Kujala score at short-, mid-, and long-term follow-up, with subanalyses for the pediatric population.

RESULTS

We included 510 patients from 10 RCTs in the meta-analysis. Redislocation rate was 0.40 (0.25 to 0.66; P < .001) and 0.58 (0.29 to 1.15; P = .12) at the short- and mid-term follow-ups, respectively, and the risk ratio for the need for further operations at 6 to 9 months' follow-up was 0.14 (0.02 to 1.03; P = .05), all favoring surgery. Concerning the Kujala score, an advantage of the surgical approach of 10.2 points (1.6 to 18.7; P = .02) at short-term follow-up was seen, whereas long-term follow-up results were similar between the groups. The subanalysis of the pediatric population at heterogeneous follow-up confirmed a lower risk of recurrence in surgery, with a risk ratio of 0.60 (0.26 to 1.37; P = .22), although not significant.

CONCLUSION

The literature documents a low number of high-level trials. The meta-analysis of RCTs underlined that the redislocation rate is higher with the nonsurgical approach compared with the surgical one. Moreover, when looking at the clinical outcome, more favorable findings were found with the surgical approach up to 6 years, whereas results seems to be similar at a longer follow-up after either surgical or nonsurgical treatment of primary LPD.

LEVEL OF EVIDENCE

II, meta-analysis of level I and level II randomized clinical trials.

The Medial Patellofemoral Ligament Is a Dynamic and Anisometric Structure: An In Vivo Study on Length Changes and Isometry

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction is associated with a high rate of complications, including recurrent instability and persistent knee pain. Technical errors are among the primary causes of these complications. Understanding the effect of adjusting patellofemoral attachments on length change patterns may help surgeons to optimize graft placement during MPFL reconstruction and to reduce graft failure rates.

PURPOSE

To determine the in vivo length changes of the MPFL during dynamic, weightbearing motion and to map the isometry of the 3-dimensional wrapping paths from various attachments on the medial femoral epicondyle to the patella.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Fifteen healthy participants were studied with a combined computed tomography and biplane fluoroscopic imaging technique during a lunge motion (full extension to ~110° of flexion). On the medial femoral epicondyle, 185 attachments were projected, including the anatomic MPFL footprint, which was divided into 5 attachments (central, proximal, distal, posterior, and anterior). The patellar MPFL area was divided into 3 possible attachments (proximal, central, and distal). The length changes of the shortest 3-dimensional wrapping paths of the various patellofemoral combinations were subsequently measured and mapped.

RESULTS

For the 3 patellar attachments, the most isometric attachment, with an approximate 4% length change, was located posterior and proximal to the anatomic femoral MPFL attachment, close to the adductor tubercle. Attachments proximal and anterior to the isometric area resulted in increasing lengths with increasing knee flexion, whereas distal and posterior attachments caused decreasing lengths with increasing knee flexion. The anatomic MPFL was tightest in extension, decreased in length until approximately 30° of flexion, and then stayed near isometric for the remainder of the motion. Changing both the femoral and patellar attachments significantly affected the length changes of the anatomic MPFL ( P < .001 for both).

CONCLUSION

The most isometric location for MPFL reconstruction was posterior and proximal to the anatomic femoral MPFL attachment. The anatomic MPFL is a dynamic, anisometric structure that was tight in extension and early flexion and near isometric beyond 30° of flexion.

CLINICAL RELEVANCE

Proximal and anterior MPFL tunnel positioning should be avoided, and the importance of anatomic MPFL reconstruction is underscored with the results found in this study.

Patient-Reported Outcome Measures for Patellofemoral Instability: a Critical Review

PURPOSE OF REVIEW

The purpose of this paper was to review the current psychometric properties of patient-reported outcome measures that are commonly used for patients with patellofemoral instability. This review provides evidence to guide the selection of subjective outcome measures for assessing outcomes in clinical care and research studies.

RECENT FINDINGS

At the present time, there are two patient-reported outcome measures that have been designed for, and tested on, large cohorts of patellofemoral instability patients, the Banff Patella Instability Instrument (BPII) and the Norwich Patellar Instability Score (NPI). The BPII is a wholistic quality of life outcome measure and the NPI is a symptom score. The use of disease-specific outcome measures such as the BPII and NPI, in combination with generic knee, functional activity, and/or psychological outcome measures that have been proven to be valid and reliable for the patellofemoral instability population, is most likely to provide a well-rounded evaluation of treatment outcomes.

The "Journal of Functional Morphology and Kinesiology" Journal Club Series: Highlights of Recent Papers in Pediatric Exercise

We are glad to introduce the ninth Journal Club. This edition is focused on several relevant studies published in the last years in the field of Pediatric Exercise, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport as seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.