First-time Patellar Dislocation Research Articles

Surgical management of first-time patellar dislocations in paediatric patients may lower rates of redislocation compared to conservative management: A systematic review and meta-analysis.

The purpose of this study is to assess whether early surgical intervention for first-time patellar dislocations in paediatric patients is superior to conservative management. We hypothesized that surgical intervention would lead to lower redislocation rates compared to conservative treatment. Three online databases (PubMed, MEDLINE and EMBASE) were searched from inception to 14 March 2024 to identify studies investigating the management options for acute first-time patellar dislocations in paediatric patients. Data pertaining to patient demographics, patient management, redislocation rates and Kujala scores, evaluating function, were abstracted. Weighted means and meta-analyses were conducted to compare rates of redislocation, as well as Kujala scores. The quality of included studies was assessed using the methodological index for non-randomized studies criteria for non-randomized studies and the ROB2 tool for randomized controlled trials (RCTs). A total of 11 studies and 761 patients were included in this review. The weighted mean post-operative combined rates of redislocation in the surgical group was 25.1%, compared to 46.4% in the conservative group at a mean follow-up of 53.2 months (12-168). The relative risk (RR) of redislocation was 0.82 (95% confidence interval [CI]: 0.65-1.04, I2 = 0%, p = 0.11), favouring surgery compared to conservative management. A subgroup meta-analysis of two recent RCTs with 110 patients demonstrated an RR of redislocation of 0.53 (95% CI: 0.31-0.91, I2 = 0%, p = 0.02), favouring surgery. Kujala scores among three comparative studies showed a mean difference of -2.7 (95% CI: -6.1 to 0.68, I2 = 0%, p = 0.12), favouring conservative treatment. The weighted mean redislocation rate in 131 patients undergoing medial patellofemoral ligament reconstruction (MPFLR) was 3.1%, compared to 39.4% in 203 patients undergoing other surgical procedures, such as lateral release and medial imbrication, Roux-Goldwaith and MPFL repair. Furthermore, the conservative groups experienced a complication rate of 0.9% compared to 2.9% across the surgical groups. Surgical management for first-time patellar dislocations in a paediatric population, particularly MPFLR, may be more beneficial in lowering redislocation rates than conservative management. No significant differences in Kujala scores were found. Level IV.

To Operate or Not? Evaluating the Best Approach for First-Time Patellar Dislocations: A Review.

Background: The optimal management of first-time patellar dislocations remains a subject of debate. While surgical intervention is often recommended to reduce the risk of redislocation, the benefits over conservative treatment regarding knee function and complication rates are not clearly established. This systematic review aims to compare the effectiveness of surgical versus conservative treatment in preventing redislocation and improving knee function, while also considering complication rates. Methods: A comprehensive search of databases, including PubMed, Scopus, and Web of Science, was conducted up to July 2024. Seven randomized controlled trials involving 411 participants were included. The primary outcome was the redislocation rate, with secondary outcomes including knee function, complication rates, and the need for re-interventions. The quality of the studies was assessed using the PEDro scale. Results: Surgical treatment generally resulted in lower redislocation rates compared to conservative management. However, the improvement in knee function was inconsistent, with some studies showing no significant differences or even favoring conservative treatment. Surgical intervention was associated with a higher risk of complications and re-interventions, particularly in older studies with less advanced techniques. Conclusions: Surgical intervention appears effective in reducing redislocation rates but comes with a risk of complications. Conservative treatment remains a viable option, particularly for patients with lower activity levels or higher surgical risks. The decision between surgical and conservative management should be individualized, taking into account patient-specific factors and potential risks. Further high-quality research is needed to provide more definitive guidance.

Application of a machine learning and optimization method to predict patellofemoral instability risk factors in children and adolescents.

Conservative treatment remains the standard approach for first-time patellar dislocations. While risk factors for patellofemoral instability, a common paediatric injury, are well-established in adults, data concerning the progression of paediatric recurrent patellar dislocation remain scarce. A reproducible method was developed to quantitatively assess the patellofemoral morphology and anatomic risk factors in paediatric patients using magnetic resonance imaging (MRI) and machine learning analysis. Data were analyzed from a retrospective review (2005-2022) of paediatric patients diagnosed with acute lateral patellar dislocation (54 patients) who underwent MRI and were compared with an age-based control group (54 patients). Patellofemoral, tibial, tibiofemoral and patellar height parameters were measured. Differences between groups were analyzed with respect to MRI parameters. The potential diagnostic utility of the parameters was assessed via machine learning and genetic algorithm analyses. Significant differences were observed between the two groups in six patellofemoral morphological parameters. Regarding patellar height morphological parameters, all methods exhibited significant between-group differences. Among the tibia and tibiofemoral morphological parameters, only the tibial tubercle-trochlear groove distance exhibited significant differences between the two groups. No sex-related differences were present. Significant variations were observed in patellar height parameters, particularly in the Koshino-Sugimoto (KS) index, which had the highest area under the curve (AUC: 0.87). Using genetic algorithms and logistic regression, our model excelled with seven key independent variables. KS index and Wiberg index had the strongest association with lateral patellar dislocation. An optimized logistic regression model achieved an AUC of 0.934. Such performance is considered clinically relevant, indicating the model's effectiveness for the intended application. Level Ⅲ.

Patient-reported Outcomes Following Nonoperative Treatment of Pediatric First‐Time Patellar Dislocation

BackgroundPatellar instability is a common pediatric knee injury. The purpose of this study was to analyze PROMs (patient-reported outcome measures) after non-operative treatment following a first-time pediatric patellar dislocation. MethodsIn this single-center, retrospective study, patients <18 years old between January 2012 and December 2019 with a first-time patellar dislocation were evaluated. From this cohort, we included all those patients who initially underwent non-operative management and followed up for at least 1 year. Measures of patellar height and patellofemoral dysplasia were collected. Patient-reported outcome measures (PROMs) were collected at the initial and follow-up visit. Univariate and multivariate analyses were utilized to determine the rate and risk factors for recurrence and the changes in PROMs. Results176 knees were included in the initial analysis, and 80 in the pre- and post-PROM analysis. There was a 41% rate of recurrence at a mean of 16.4 months of follow-up. In a multivariate logistic regression model, trochlear dysplasia (OR:4.53, 95%CI: 1.61–12.7, P=0.004), patella alta (OR:4.27, 95%CI: 1.76–10.3, P<0.001), and tibial tubercle trochlear groove (TT-TG) > 15mm (OR:2.49, 95%CI: 1.3–6.03, P<0.001) were significant risk factors for recurrence. Patients with or without recurrence showed significant improvements in PROMs at 1 year follow-up. However, both groups had mean scores below the population average. Regardless of recurrence or not, KOOS-Child QoL scores ranked the lowest among all PROM scores at the final follow-up. ConclusionsThe findings of this study provide further evidence of the high rate of recurrent instability and important associated risk factors to consider. We also found that despite the overall improvement in all PROM subscales 1 year following the initial episode, both recurrence and no-recurrence groups demonstrated lower mean PROM scores than normal values. Furthermore, quality of life subscales showed the smallest improvement among all patients. Our results may be used to counsel patients and families regarding expectations after first-time and recurrent patellar dislocations. Key conceptsPatellar instability is one of the most common pediatric sports injuries with a high risk of recurrence.(1)In the absence of other factors, a first-time patellar dislocation is generally treated non-operatively, but the long-term outcomes are not clear.(2)In this study, we found a high risk of recurrent dislocation. In addition, while the PROMs improved for all patients, even patients without evidence of further instability demonstrated patient-reported outcomes lower than the general population.(3)Future research may reveal subtle residual instability or other factors as the reason for the lower functional status and also compare these outcomes with operative reconstruction. Level of evidenceCase series, Level IV

Patellofemoral Instability in Pediatric and Adolescent Athletes: A Review of Risk Factors and Treatments.

Pediatric patellar instability can impair function and restrict activity participation. If left untreated, it can lead to a degenerative knee. The incidence of patellar dislocations is highest in adolescents between 10 and 17 years of age; more than half of all first-time patellar dislocations occur during sports. This article reviews the evidence of risk factors for traumatic patellar instability, surgical interventions, and return-to-sport (RTS) considerations for pediatric and adolescent athletes. Anatomic risk factors for patellar instability in pediatric and adolescent patients include trochlear dysplasia, elevated tibial tuberosity-trochlear groove (TT-TG) distance, patella alta, genu valgum, femoral anteversion and tibial torsion, and hyperlaxity.

Consensus-Based Guidelines for Management of First-Time Patellar Dislocation in Adolescents.

The management of first-time patellar dislocation remains variable, with limited evidence to support or compare different operative and nonoperative modalities. The primary aim was to establish consensus-based guidelines for different components of nonoperative treatment following a first-time patellar dislocation. The secondary aim was to develop guidelines related to management after failed nonoperative treatment. The tertiary aim was to establish consensus-based guidelines for the management of first-time patellar dislocation with a concomitant osteochondral fracture. A 29-question, multiple-choice, case-based survey was developed by 20 members of the Patellofemoral Research Interest Group of the Pediatric Research in Sports Medicine Society. The survey consisted of questions related to demographic information, management of first-time patellar dislocation without an osteochondral fracture, and management of first-time patellar dislocation with a 2cm osteochondral fracture. The survey underwent 2 rounds of iterations by Patellofemoral Research Interest Group members and the final survey was administered to Pediatric Research in Sports Medicine members, using REDCap. Consensus-based guidelines were generated when more than 66% of respondents chose the same answer. Seventy-nine of 157 (50%) eligible members responded. Sixty-one were orthopaedic surgeons and 18 were primary sports medicine physicians. Eleven consensus-based guidelines were generated based on survey responses. Those that met the criteria for consensus included initial knee radiographs (99% consensus), nonoperative treatment for first-time patellar dislocation without an osteochondral fracture (99%), physical therapy starting within the first month postinjury (99%), with return to sport after 2 to 4 months (68%) with a brace (75%) and further follow-up as needed (75%). Surgical treatment was recommended if there were patellar subluxation episodes after 6 months of nonoperative treatment (84%). Patellar stabilization should be considered for a first-time dislocation with an osteochondral fracture (81.5%). Consensus-based guidelines offer recommendations for the management of first-time patellar dislocation with or without an osteochondral fracture. Several changing trends and areas of disagreement were noted in clinical practice. In the absence of high-level evidence, consensus-based guidelines may aid in clinical decision-making when treating patients following a first-time patellar dislocation. These guidelines highlight the evolving trends in clinical practice for the management of first-time patellar dislocation. Areas not reaching consensus serve as topics for future research.

Epidemiology of Lateral Patellar Dislocation Including Bone Bruise Incidence: Five Years of Data from a Trauma Center.

Systematic summary of the epidemiology of patellar dislocation is rare. This study aims to investigate sex-, age-, type-, injury causing events-, incidence of bone bruise and time from last injury (TFLI)-specific characteristics, and detail the epidemiological characteristics of patellar dislocation. In this descriptive epidemiological study, a total of 743 patients who have a history of lateral patellar dislocation with either first-time patellar dislocation (FPD) or recurrent patellar dislocation (RPD) between August 2017 and June 2022 at our institution met the inclusion criteria and were selected in this study. Patient characteristics including the type, gender, age, events leading to patellar dislocation, incidence of patellar bone bruise, and the time from last injury (TFLI) of patellar dislocation were retrospectively obtained and described. Magnetic resonance imaging scans (MRI) of the knee were reviewed for insuring bone bruise. Among the 743 patients with patellar dislocation who required surgical reconstruction of the medial retinaculum, 418 (56.2%) had RPD and 325 (43.8%) had FPD. There were more females (65.0%) than males (35.0%) in patellar dislocation patients. Among the female patients, those aged <18 years had higher incidence (31.4%) of patellar dislocation. Among the male patients, those aged <18 and 19-28 years had higher incidence (16.8%) of patellar dislocation. Of all age groups, the prevalence rate of patellar dislocationwas high in juvenile population and females, but with no statistical significance. The most common patellar dislocation-causing event was sport accidents (40.1%), followed by life accidents (23.2%). The incidence of left-knee patellar dislocation was slightly higher than that of right-knee patellar dislocation. The incidence of patellar bone bruise of RPD (63.2%) was significantly lower (p < 0.05) than that of FPD (82.2%). Patellar dislocation patients with bone bruise had shorter time from last injury (TFLI) than those without patellar bone bruise (p < 0.05). The incidence of bone bruise of RPD was lower than that of FPD, and patients with patellar bone bruise may have a shorter time from last injury than those without bone bruise.

Poster 137: Influence of Body Mass Index on T1ρ Relaxation Times for Patellofemoral Cartilage: Patellar Dislocation Patients vs. Healthy Controls

Objectives: Patellar dislocations are associated with patellofemoral cartilage degradation following injury and a high risk of patellofemoral post-traumatic osteoarthritis (PTOA). Obesity is also a primary risk factor for patellofemoral cartilage degradation and OA, but the influence of obesity on cartilage degradation follow patellar dislocations is unknown. The current study uses T1ρ-based relaxation time mapping of patellofemoral cartilage to evaluate the influence of body mass index (BMI) on cartilage properties in the acute phase following a patellar dislocation, and compares the results to healthy knees. The hypothesis of the study is increasing BMI is associated with cartilage matrix degeneration for injured and healthy knees. Methods: The IRB-approved study focused on a BMI range from underweight to obese (&lt; 40 kg/m2). The population included 18 patients being treated conservatively for a unilateral, first-time patellar dislocation (20 ± 8 years, 9 females, BMI: 24 ± 5 kg/m2, 56 ± 39 days since dislocation), 12 patients being treated conservatively for multiple unilateral dislocations (19 ± 6 years, 9 females, 24 ± 5 kg/m2, 67 ± 35 days since most recent dislocation), and 16 healthy controls (21 ± 7 years, 7 females; 21 ± 7 kg/m2). MRI scans included a 3D water excitation double echo steady state (DESS) scan of the knee for segmentation of the cartilage surfaces (slice thickness of 0.7 mm) and a T1ρ relaxation time scan (fat saturated scan, slice thickness = 4 mm, spin lock times = 0, 10, 40, and 80 ms, spin-lock frequency = 500 Hz). Long T1ρ relaxation times indicate low proteoglycan concentration within cartilage. Automated algorithms based on machine learning were used to segment cartilage on the patella and within the trochlear groove. Additional automated algorithms mapped T1ρ relaxation times to the reconstructed cartilage surfaces (Fig. 1). Mean T1ρ relaxation times were quantified for patellar and trochlear groove cartilage for each knee. Linear regression were used to correlate T1ρ relaxation times with BMI for the single dislocation, multiple dislocations, and control groups. Statistical significance was set at p &lt; 0.05. Results: Patellofemoral T1ρ relaxation times increased with BMI for healthy control subjects, but decreased with BMI following patellar dislocation. For control subjects, the increase in T1ρ relaxation times with BMI was significant for cartilage on the patella and within the trochlear groove (r2 &gt; 0.4, p &lt; 0.01). For patients being treated for a single dislocation and multiple dislocations, the decrease in T1ρ relaxation times with increasing BMI was significant for cartilage on the patella and within the trochlear groove (r2 &gt; 0.25, p &lt; 0.025 for single dislocations, r2 &gt; 0.3, p &lt; 0.05 for multiple dislocations). Conclusions: The expected increase in T1ρ relaxation times with BMI was observed for healthy control subjects, but not for patients being treated for patellar dislocations. Elevated T1ρ values indicate loss of proteoglycan content that reduces cartilage integrity and could be an initiation point for progression to OA. For cartilage throughout the patellofemoral joint, T1ρ relaxation times decreased as BMI increased following patellar dislocation. The relationships were similar following one dislocation and multiple dislocations. The regression lines for injured knees and controls crossed at a BMI of approximately 25 for patellar and trochlear groove cartilage, indicating T1ρ relaxation times are higher for injured knees than healthy controls only for patients with a BMI &lt; 25 (underweight or healthy weight). Multiple previous studies have identified elevated patellofemoral cartilage relaxation times from quantitative MRI following single and multiple patellar dislocations, but no study has previously attributed the difference to patients with a low BMI. The mechanism by which a high BMI limits cartilage degradation following patellar dislocation is currently unknown. The opposing relationships between T1ρ relaxation times and BMI for injured knees and controls occur despite similar ranges for T1ρ times and BMI. The primary difference between injured knees and controls is the recent dislocation event, and the ensuing inflammatory response. The single and multiple dislocation groups have a recent dislocation and inflammation in common despite differences in time since the first dislocation. Impact injury to cartilage is primarily limited to the medial patella, so is unlikely to cause the difference in trends. Pathologic patellofemoral anatomy is a characteristic of knees with patellar instability that could also influence the relationship with BMI. Additional enrollment and characterization of anatomical factors and inflammatory conditions is needed to identify factors that interact with BMI. Follow up analyses are also needed to determine if these relationships weaken with time from injury.

MPFL Repair Versus Rehabilitation After Acute First-Time Patellar Dislocation: A Systematic Review And Meta-Analysis

MPFL Repair Versus Rehabilitation After Acute First-Time Patellar Dislocation: A Systematic Review And Meta-Analysis

Current understanding of the first-time patellar dislocation

Current understanding of the first-time patellar dislocation

Incidence and concomitant chondral injuries in a consecutive cohort of primary traumatic patellar dislocations examined with sub-acute MRI

PurposeTo present age- and sex-specific cumulative annual incidences of primary traumatic lateral patellar dislocation (LPD) and to detail patient characteristics and concomitant chondral injuries including osteochondral fractures, as visualized on magnetic resonance imaging (MRI), in a large consecutive cohort of knee-injured individuals.MethodsData on primary traumatic lateral patellar dislocations were collected from a large consecutive cohort of knee injuries examined with sub-acute MRI in a single centre with a well-defined catchment area. Annual incidences for different age-groups in relation to gender were calculated together with the risk of concomitant chondral and osteochondral injury, during sports and in general.ResultsA total of 184 primary patellar dislocations were identified in the cohort of 1145 acute knee injuries (n=175) and surgical records (n=9). Knee MRI was performed within a median of six days of injury. Median age of patients with primary LPD was 16 years (interquartile range, 14–21; range, 9–47) and 41% were females. Males were significantly older than females at the time of injury (median age 17 vs. 15, P = 0.021) and sustained their primary LPD during sports more often than females (65 vs. 40%, P < 0.001). Primary LPD occurred most frequently at the age of 13 to 15 years where the annual incidence was 125 (95% CI, 96–160) per 100,000 persons. The overall annual incidence of primary LPD was 14 (95% CI, 12–16) per 100,000 persons, with a predominance of males versus females (17 vs. 11, P = 0.01). Concomitant lesions to joint surfaces were displayed on MRI or during surgery in 75 (43%) knees. Osteochondral fractures were seen in 32 knees (18%). We found no statistically significant difference in the risk of osteochondral fracture between those injured during sports or during leisure activity (14 vs. 24%, P = 0.08).ConclusionsThe annual incidence of first-time patellar dislocation was found to be 14 per 100,000 individuals with the highest incidence found among those aged 13–15 years. Primary LPD was more common among males and was sustained during sports activity in 55% of the cases. Associated injuries to the chondral surfaces should be expected in 43% of knees with primary LPD where 18% represent osteochondral fractures.

Children’s orthopaedics

The February 2023 Children’s orthopaedics Roundup360 looks at: Trends in management of paediatric distal radius buckle fractures; Pelvic osteotomy in patients with previous sacral-alar-iliac fixation; Sacral-alar-iliac fixation in patients with previous pelvic osteotomy; Idiopathic toe walking: an update on natural history, diagnosis, and treatment; A prediction model for treatment decisions in distal radial physeal injuries: a multicentre retrospective study; Angular deformities after percutaneous epiphysiodesis for leg length discrepancy; MRI assessment of anterior coverage is predictive of future radiological coverage; Predictive scoring for recurrent patellar instability after a first-time patellar dislocation.

Lateral Patellar Instability.

Patellar instability represents a common problem with an evolving understanding and multifactorial pathoetiology. Treatment plans should be based on the identification of contributing anatomical factors and tailored to each individual patient. Risks for recurrent instability are dependent on several patient-specific factors including patella alta, increased tibial tubercle-to-trochlear groove (TT-TG) distance, trochlear dysplasia, younger skeletal age, and ligamentous laxity. Cartilage or osteochondral lesions and/or fractures are commonly observed in first-time patellar dislocation, and magnetic resonance imaging (MRI) should be strongly considered. Advanced imaging modalities, such as computed tomography (CT) or MRI, should also be obtained preoperatively to identify predisposing factors and guide surgical treatment. Medial patellofemoral ligament (MPFL) reconstruction with anatomical femoral tunnel positioning is associated with lower recurrence rates compared with MPFL repair and has become a common and successful reconstructive surgical option in cases of instability. Lateral retinacular tightness can be addressed with lateral retinacular release or lengthening, but these procedures should not be performed in isolation. Tibial tubercle osteotomy is a powerful reconstructive tool in the setting of underlying skeletal risk factors for instability and can be of particular benefit in the presence of increased TT-TG distance (>20 mm), and/or in the setting of patella alta. The indications for trochleoplasty are still developing along with the clinical evidence, but trochleoplasty may be indicated in some cases of severe trochlear dysplasia. Several surgical techniques have indications in specific clinical scenarios and populations, and indications, risks, and benefits to each are progressing with our understanding. Combined femoral derotational osteotomy and MPFL reconstruction can be considered for patients with a femoral anteversion angle of >30° to improve patient outcomes and reduce recurrence rates.

Retracted: Anatomic Risk Factors for Osteochondral Fracture of Acute First-Time Patellar Dislocation in Adolescents: A Retrospective Magnetic Resonance Imaging Study.

[This retracts the article DOI: 10.1155/2022/6723326.].

Management of the first episode of traumatic patellar dislocation: an international survey.

This international survey aimed to evaluate the potential controversies regarding the management of first patellar dislocation amongst experienced knee surgeries in the treatment of the first episode of patellar dislocation without osteochondral fragments. An online survey was conducted from February 2021 to December 2021 to assess the global trend in the diagnosis and management of first-time patellar dislocation without osteochondral fragments. The online survey was accessible on the homepage of the website of the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA). The questionnaire consisted of multiple-choice questions and was divided into three sections. The first section consisted of eight questions regarding demographic information, professional activity, and responder experience. The second section consisted of 13 questions regarding the approach to a first patellar dislocation (clinical examination, imaging, and rehabilitation). The third section contained 2 questions concerning the relevance of patient characteristics to the therapeutic algorithm (age, sports, and pathoanatomical predisposing risk factors). A total of 438 orthopaedic surgeons worldwide completed the questionnaire. At the first approach to diagnose a first-time patellar dislocation, 251 (57%) of the surgeons requested plain radiographs, and 158 (36%) requested magnetic resonance imaging (MRI). In conservatively treated patients, 368 (84%) of the respondents recommended the use of a knee brace. Amongst them, 14 (3%) advocated its use for one week, 75 (17%) for two weeks, 123 (28%) for three weeks, 105 (24%) for four weeks, and 97 (22%) for six weeks. In conservatively treated patients, 215 (49%) of the surgeons recommended load to tolerance, 148 (34%) recommended 30% to 60% of the bodyweight, and 75 (17%) advised against weight-bearing. More than half of the surgeons considered a patient aged less than 35years practising contact sports to be a candidate for the medial patello-femoral ligament (MPFL) procedure. In addition, a tibial tuberosity to trochlear groove distance (TT-TG) distance of 15 to > 20mm (for > 75% of the surgeons) and a trochlea types C and D (for > 70% of the surgeons) were considered possible indications for direct surgical management. At the first approach to diagnose a first-time patellar dislocation, plain radiographs and MRI should be performed. In conservatively treated patients, most of the surgeons recommend weight-bearing to tolerance and a knee brace during the first four weeks, with range of motion of full extension to 30° during the first 15days and up to 60° for an additional 15days. Surgical management should be performed in patients in the second and third decades of life practising contact sports and in those patients who present types C and D trochlea dysplasia and patella alta. IV.

MPFL repair after acute first-time patellar dislocation results in lower redislocation rates and less knee pain compared to rehabilitation: a systematic review and meta-analysis.

This study aimed to explore the efficacy of medial patellofemoral ligament (MPFL) repair versus nonoperative rehabilitation treatment on the rate of patellar redislocation and functional outcomes in skeletally mature patients with traumatic, first-time patellar dislocations. MEDLINE, PubMed and EMBASE were searched from database inception to May 2022 for studies examining the management options for acute first-time patellar dislocations. This study was conducted in accordance with PRISMA and R-AMSTAR guidelines. Data on redislocation rates, functional outcomes including the Kujala score for anterior knee pain,and complication rates were extracted. A meta-analysis was used to pool the mean postoperative Kujala score and calculate the proportion of patients sustaining redislocations using a random effects model. Quality assessment of included studies was performed for all included studies using the MINORS and Detsky scores. This review included a total of 25 studies and 1,361 patients.The pooled mean redislocation rate in 15 studies comprising 798 patients in the rehabilitation group was 30% (95% CI 25-36%, I2 = 65%). Moreover, the pooled mean redislocation rate in 10studies comprising 170 patients undergoing MPFL repair was 7% (95% CI 3-12%, I2 = 30%).The pooled mean postoperative Kujala score in 8 studies comprising 396 patients in the rehabilitation group was 82.5 (95% CI 78.3-86.8, I2 = 91%), compared to a score of 88 (95% CI 87-90, I2 = 76%) in 3 studies comprising 94 patients in the repair group. Range of motion deficits was reported in 3.8% of 893 patients in the rehabilitation group and 2.0% of 205 patients in the repair group. MPFL repair resulted in a lower rate of redislocation, less knee pain, and noninferiority with respect to a range of motion deficits compared to nonoperative treatment for the management of acute first-time patellar dislocations. IV.

Medial Patellofemoral Ligament Reconstruction is Preferred to Repair or Reefing for First-Time Patellar Dislocation: A Systematic Review and Meta-analysis.

The purpose of this systematic review aimed to investigate the clinical outcome of medial patellofemoral ligament (MPFL) reconstruction, MPFL repair and medial reefing for patients with first-time patellar dislocation. Databases of PubMed, EMBASE, Cochrane Library and Web of Science were searched up to May 8, 2022. Only articles treating first-time patellar dislocation with MPFL reconstruction, MPFL repair and medial reefing were included in the analysis. Eligible identification, data extraction, quality assessment and statistical analysis were performed by two independent reviewers. The primary outcome measures were the incidences of postoperatively redislocation and reoperation. The second outcomes were the Kujala functional score and complications (including infection, osteoarthritis, and loss of range of motion). Twenty-two studies involving 668 patients met the inclusion criteria. Of which, four studies involving 126 patients were in MPFL reconstruction group, ten studies involving 220 patients in MPFL repair group and 9 studies involving 322 patients in medial reefing group. Our results showed that the MPFL reconstruction (1.8%, 95% CI -0.5 to 4.0%) had a significantly lower rate of postoperative redislocation and reoperation rate than the MPFL repair (15.4%, 95% CI 5.2-25.7%) and medial reefing (18.0%, 95% CI 9.3-26.7%). Besides, no significant differences were found in the Kujala score and complication rate among the three treatments. The available evidence demonstrated that MPFL reconstruction could achieve significantly lower redislocation rate and reoperation rate than MPFL repair and medial reefing after first-time patella dislocation. Furthermore, there was not enough evidence to reveal that MPFL reconstruction provided better functional outcome compared with MPFL repair and medial reefing. MPFL reconstruction is a preferred surgical treatment for patients with first-time patellar dislocation. Level IV, systematic review of Level I-IV.

The incidence of musculoskeletal injuries: a systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to gather epidemiological information on selected musculoskeletal injuries and to provide pooled injury-specific incidence rates. PubMed (National Library of Medicine) and Scopus (Elsevier) databases were searched. Articles were eligible for inclusion if they reported incidence rate (or count with population at risk), contained data on adult population, and were written in English language. The number of cases and population at risk were collected, and the pooled incidence rates (per 100,000 person-years) with 95% confidence intervals (CIs) were calculated by using either a fixed or random effects model. The screening of titles yielded 206 articles eligible for inclusion in the study. Of these, 173 (84%) articles provided sufficient information to be included in the pooled incidence rates. Incidences of fractures were investigated in 154 studies, and the most common fractures in the whole adult population based on the pooled incidence rates were distal radius fractures (212.0, 95% CI 178.1 to 252.4 per 100,000 person-years), finger fractures (117.1, 95% CI 105.3 to 130.2 per 100,000 person-years), and hip fractures (112.9, 95% CI 82.2 to 154.9 per 100,000 person-years). The most common sprains and dislocations were ankle sprains (429.4, 95% CI 243.0 to 759.0 per 100,000 person-years) and first-time patellar dislocations (32.8, 95% CI 21.6 to 49.7 per 100,000 person-years). The most common injuries were anterior cruciate ligament (17.5, 95% CI 6.0 to 50.2 per 100,000 person-years) and Achilles (13.7, 95% CI 9.6 to 19.5 per 100,000 person-years) ruptures. The presented pooled incidence estimates serve as important references in assessing the global economic and social burden of musculoskeletal injuries.Cite this article: Bone Joint Res2022;11(11):814-825.

Anatomic Risk Factors for Osteochondral Fracture of Acute First-Time Patellar Dislocation in Adolescents: A Retrospective Magnetic Resonance Imaging Study.

Objective To analyze the risk factors for osteochondral fracture (OCF) of first-time acute patellar dislocation (APD) through measurements of patellofemoral anatomy in adolescents. Methods In this prospective study, all patients were divided into two groups according to whether OCF was detected on magnetic resonance imaging (MRI): Group A (associated with OCF) and Group B (without OCF). Patellofemoral anatomy was evaluated with four aspects including trochlear/patellar dysplasia, patella location, patellofemoral matching, and morphologic classification. On MRI scans, trochlear facet asymmetry ratio (TFAR), lateral trochlear inclination (LTI), sulcus angle (SA), trochlear depth (TD), and patellar depth (PD) were measured to assess trochlear/patellar dysplasia. Insall–Salvati index (ISI), Caton–Deschamps index (CDI), Blackburne–Peel index (BPI), lateral patellofemoral angle (LPFA), patellar tilt angle (PTA), and lateral patellar displacement (LPD) were measured to show the location of patella. Patellofemoral matching was analyzed through the measurements of patellofemoral congruence angle (PFCA), patellofemoral index (PFI), and patellotrochlear index (PTI). Results A total of ninety-four adolescents from 49 boys and 45 girls (mean age, 15 years; range, 10–18 years) with first-time APD were recruited and included in Group A (65) and Group B (29). The PFI (2.62 ± 0.51 vs. 2.10 ± 0.44) and PTI (0.28 ± 0.05 vs. 0.22 ± 0.07) were significantly higher in Group B than Group A (P < 0.05). There were no significant differences in other quantitative outcomes of the two groups (P > 0.05). The distribution of Dejour/Wiberg classification was statistically similar between the two groups (P > 0.05). Conclusions Adolescent patients with first-time APD complicating OCF have closer morphologic features of patellofemoral dysplasia and patella location when compared to adolescents without OCF. Abnormal patellofemoral matching increases the risk of OCF after first-time APD in adolescents.

Predictive Scoring for Recurrent Patellar Instability After a First-time Patellar Dislocation.

Patellofemoral instability is a common acute knee injury seen in the pediatric population. First-time patellar dislocations usually undergo conservative management, but ~15% to 80% of patients experience recurrent instability. This study aims to develop a prediction model using radiographic parameters of the patellofemoral joint seen on computed tomography scans in different degrees of knee flexion, to determine the risk of recurrence after the first episode of patellofemoral instability. A 12-year retrospective case-control study was performed. All patients in a single institution aged 18 years or younger who had a computed tomography patellar tracking scan performed for patellar instability were included. Predictors included in the score were determined through backward logistic regression and compared using receiver operating characteristic curve analysis. This study revealed that recurrent dislocation in first-time patellofemoral dislocation could be accurately predicted using the prediction score that consisted of age, tibial tubercle-trochlear groove distance and congruence angle at 10- and 20-degree flexion. The sensitivity of the score was 100% and specificity was 73.3%. Three diagnostic zones were identified and used to categorize patients into low-, intermediate-, and high-probability groups. This study presented a scoring system that incorporated radiographic knee kinematics in the risk assessment for recurrent patellofemoral instability for patient stratification. The scoring system could guide the decision for early surgical intervention after the first-episode patellofemoral dislocation for patients at high risk of recurrent patellofemoral dislocation.