Traumatic Patellar Dislocation Research Articles

Turkish Version of the Norwich Patellar Instability Score: Minimal Detectable Change among Patients with Traumatic Patellar Dislocation

Objective: This study aimed to calculate the minimal detectable change (MDC) in the Norwich Patellar Instability score (NPI) and validate the score for Turkish-speaking individuals with patellar instability. Method: Sixty-four patients (mean age 21.87 ± 9.44 years) who had experienced at least one patellar dislocation during athletic activities participated in the study. The Turkish version of the NPI (NPI-T) was evaluated for reliability and internal consistency. The Minimal Detectable Change was calculated as an overall value for the participants. MDC was calculated based on the standard error of measurement (SEM) and the selected confidence level (ICC) for the study population. Pearson's correlations were examined to assess construct validity between the Kujala Patellofemoral Disorder score and the Lysholm Knee Score. Result: The MDC for the NPI-T was 17.29, with a SEM of 6.24. The score demonstrated high internal consistency, with a Cronbach’s alpha value of 0.85, indicating substantial reliability. The consistency of measurements was excellent, with an ICC2,1 of 0.95. Additionally, the NPI-T score exhibited a strong negative correlation with both the Kujala (r = -0.85, p < 0.001) and Lysholm (r = -0.89, p < 0.001) scores. A floor effect was observed, but no ceiling effect was present. Conclusion: The study confirms that the NPI-T demonstrates strong psychometric properties, with high internal consistency and excellent reliability, as evidenced by its low MDC and SEM. The use of the NPI-T as a reliable and valid tool for assessing patellar instability in patients with patellar dislocation will provide valuable information to clinicians.

Comparison of Clinical and Radiological Outcomes With Body Mass Index After Medial Patellofemoral Ligament Reconstruction.

Medial patellofemoral ligament (MPFL) reconstruction is a commonly employed surgical approach for recurrent patellar dislocation. However, the impact of elevated body mass index (BMI) on postoperative complication rates remains controversial. To compare the clinical, radiographic, and functional outcomes of patients with normal BMI (18.5-24.9 kg/m2) and those with elevated BMI (≥25 kg/m2) who underwent MPFL reconstruction for recurrent acquired lateral traumatic patellar dislocation. Cohort Study; Level of evidence, 3. A total of 70 patients who underwent MPFL reconstruction for recurrent patellar dislocation were included in this study. Patients with recurrent patellar dislocation were categorized into 2 groups based on their BMI: the normal BMI group and the elevated BMI group. Functional scores (Lysholm, International Knee Documentation Committee [IKDC], Tegner, and Kujala scores) and radiological measurements (patellar tilt angle, patellofemoral trochlear congruence, lateral patellofemoral angle, and lateral patellar displacement) were evaluated both preoperatively and at the last follow-up. The occurrence of postoperative complications at the last follow-up was also recorded. Differences in functional scores and radiological parameters before and after surgery were analyzed with paired-samples t tests or Wilcoxon signed-rank tests. Comparisons between groups were conducted using independent-samples t tests or the Kolmogorov-Smirnov test. In the normal BMI group, there were 13 male patients and 27 female patients, with a mean follow-up duration of 26.15 ± 13.16 months. The mean age in this group was 21.93 ± 7.94 years. The elevated BMI group consisted of 12 male patients and 18 female patients, with a mean follow-up duration of 27.50 ± 15.79 months and a mean age of 23.30 ± 8.43 years. At the final follow-up, the incidence of surgical failure (patellar redislocation or subluxation and necessitating secondary surgery) was significantly higher in the elevated BMI group (6 out of 30 patients; 20.0%) compared with the normal BMI group (1 out of 40 patients; 2.5%) (P < .05). Both groups demonstrated significant improvement in postoperative Lysholm, IKDC, Tegner, and Kujala scores compared with the preoperative period (P < .05). Notably, the normal BMI group had significantly higher preoperative Lysholm and Tegner scores compared with the elevated BMI group (P < .05). Furthermore, the elevated BMI group exhibited less improvement in Tegner and Kujala scores compared with the normal BMI group (P < .05). Postoperative radiological parameters in both groups returned to the normal range (P < .05). There were no statistically significant differences between the 2 groups in terms of radiological parameters and their corresponding differences. Our study demonstrated statistically significant increases in postoperative clinical scores for both groups, although the intergroup differences varied. Specifically, patients with elevated BMI demonstrated poorer preoperative Lysholm and Tegner scores. The postoperative improvement in radiological parameters was equally good between the 2 groups.

Good 5-year results and a low redislocation rate using an á la carte treatment algorithm for patellofemoral instability in patients with severe trochlea dysplasia.

Trochlear dysplasia is a major risk factor for recurrent patellar instability, reduced quality of lifeand osteoarthritis of the patellofemoral joint. Patellar instability in patients with trochlear dysplasia can be treated by trochleoplasty, usually in combination with medial patellofemoral ligament reconstruction (MPFL-R). An á la carte treatment algorithm, which also addresses patella alta, lateralisation of the tibial tuberosityand valgus or torsional malalignment when present has been standard in one clinic for treatment of patellar instability patients since 2009, based on the hypothesis that it results in optimal subjective and clinical outcome, normalisation of the lateral trochlea inclination (LTI) angle and a low rate of patellar redislocation. This prospective study reports the 5-year results for consecutive patients with high-grade trochlea dysplasia operated according to the algorithm 2010-2017, evaluated preoperatively and 1, 2and 5 years postoperatively. Clinical information on previous surgery and postoperative patellar stability, range-of-motion (ROM)and subsequent surgery were registered. Subjective outcome was evaluated by four patient-reported outcome measures (PROMs): Kujala, Lysholm, International Knee Documentation Committee and Knee injury and Osteoarthritis Outcome Score. The LTI angle was measured pre- and postoperatively on magnetic resonance imaging scans. There were 131 patients (87 females) with a median age of 22 years (range: 14-38). All had a trochleoplasty and an MPFL-R. Additional procedures (tibial tuberosity medialisation/distalisation and/or femoral/tibial osteotomy) were performed in 52%. All PROM scores improved from preoperatively to 1-year follow-up with further improvement at 2 and 5 years after surgery (p < 0.05). Three patients (2%) had a traumatic patellar dislocation 9, 12and 24 months postoperativelyand 38% underwent subsequent surgery (hardware removal, arthroscopically assisted brisement force, knee arthroscopy). A normalisation of the LTI angle (≥11°) was achieved in 76%. Treatment according to the à la carte algorithm for patients with patellar instability and high-grade trochlear dysplasia resulted in significant clinical and subjective improvement in all PROM scores and a very low redislocation rate (2%) 5years after surgery. Level II.

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

ObjectivesThe 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. MethodsIn 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. ResultsOut 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). ConclusionThe 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 evidenceLevel III.

Sulcus-deepening trochleoplasty grants satisfactory results with minimal patellofemoral arthritis at 23-30 years of follow-up.

The purpose of this study was to evaluate the radiographic and clinical outcomes of sulcus-deepening trochleoplasty at a minimum follow-up of 23 years. The authors evaluated a retrospective series of 10 patients (11 knees) who underwent trochleoplasty between 1993 and 2000. All patients were assessed at a minimum follow-up of 23 years by an independent clinician who noted any patellar redislocations and collected the International Knee Documentation Committee (IKDC), Kujala scores and range of motion. Radiographic examination was performed to assess patellofemoral arthritis using the Iwano classification. A total of 11 knees, from five women and five men aged 25.6 ± 6.9 years (range, 15-47 years) underwent trochleoplasty during the inclusion period. All 11 knees underwent adjuvant procedures during trochleoplasty (100%): 10 had tibial tuberosity osteotomy (TTO) and vastus medialis plasty and 1 had only vastus medialis plasty (had prior TTO). At a follow-up of 24.4 ± 2.1 years (range, 23-30 years), two patients were lost to follow-up (18%). The Iwano classification was Grade 1 in three patients (33%), Grade 2 in four patients (44%) and Grade 4 in two patients (22%). The flexion range was 130 ± 8.7° and satisfaction was 9.2 ± 0.7, Kujala was 76.9 ± 8.5 and IKDC was 65.5 ± 13.8. At 23-30 years following sulcus-deepening trochleoplasty in this small series of 10 patients (11 knees), patients had satisfactory clinical scores, only 1 patient reported an episode of traumatic patellar dislocation, and two knees had patellofemoral arthritis of Iwano Grade >2 (22%). Level IV.

Poster 244: Magnetic Resonance Imaging versus Diagnostic Arthroscopy to Identify Intraarticular Pathology Associated with Patellar Instability: A High Rate of Discordant Findings Altering Surgical Treatment

Objectives: While uncommon, acute traumatic patellar dislocations can lead to recurrent symptoms of patellar instability in 15% to 45% of patients. Patellar stability is an interplay of bony and soft tissue restraints as well as anatomic factors, however, a mainstay of treatment remains reconstruction of the medial patellofemoral ligament (MPFL). Instability events can lead to intra-articular derangements of the knee, both in the acute and chronic patellar instability setting. These findings may not always be appropriately identified on magnetic resonance imaging (MRI). The incidence of these “surprise” injuries have not been previously reported. The purpose of this study is to determine the rates of coexisting intra-articular pathology in patients with patellar instability requiring MPFL reconstruction and elucidate any discordance between preoperative MRI findings and diagnostic arthroscopy findings. Methods: All patients undergoing MPFL reconstruction at a single institution between 2010 and 2023 were identified and preoperative MRI reports, defined as the most recent MRI report to the date of surgery with no interval traumatic events, were queried. Records without full MRI reports as read by a radiologist or cases in which a diagnostic arthroscopy was not conducted were excluded. MRI findings were discordant from arthroscopic findings if a lesion identified on diagnostic arthroscopy was not present in the full MRI report. Procedures that were undertaken because of these missed pathologies on MRI were recorded. Results: A total of 640 patients were identified during the study period, and 507 complete records were ultimately included. Preoperative MRI identified patellar osteochondral lesions or cartilage fissures in 333 patients (66%), loose bodies in 119 patients (24%), lateral femoral condyle osteochondral lesions or fissures in 97 patients (19%) and meniscus tears in 47 patients (9%). Among these patients, 172 (34%) had a diagnosis at the time of arthroscopy which was not identified on the preoperative MRI. These arthroscopic findings resulted in 75 loose body removals, 74 patellar shaving chondroplasties, 16 partial meniscectomies, 3 microfractures, 3 osteochondral lesion open reduction internal fixation, and 2 meniscal repairs which would have been missed without diagnostic arthroscopy due to discordant MRI findings. Conclusions: Over one-third of patients at a single institution who underwent diagnostic arthroscopy in the setting of patellar instability surgery had pathology identified which required surgical intervention that was not reported on a preoperative MRI. A comparison of MRI and diagnostic arthroscopy has been extensively reported on for other knee pathologies including ACL tear and lateral meniscal tear; however, there has been no similar investigation of the reliability of MRI for identification of concomitant pathology in the setting of patellar instability to date. The findings of this study highlight the importance of diagnostic arthroscopy in the treatment of patellar instability, the frequency with which this altered treatment, and the high preponderance of discordant MRI findings.

Sulcus-Deepening Trochleoplasty With Medial Patellofemoral Ligament Reconstruction: Outcomes at 10 to 20 Years

Background: Recent systematic reviews on the outcomes of sulcus-deepening trochleoplasty with adjuvant medial patellofemoral ligament (MPFL) reconstruction at a follow-up of 2 to 6 years have found that the procedure grants good clinical outcomes with low redislocation rates. However, there is a lack of evidence in the literature regarding mid- and long-term follow-ups. Purpose: To evaluate the radiographic and clinical outcomes of thick-flap sulcus-deepening trochleoplasty with MPFL reconstruction at a minimum follow-up of 10 years to assess the signs of patellofemoral arthritis, incidence of recurrent dislocation, and grade of patient satisfaction. Study Design: Case series; Level of evidence, 4. Methods: The authors evaluated a retrospective series of 43 patients (48 knees) who underwent sulcus-deepening trochleoplasty between 2003 and 2013. All patients underwent thick-flap sulcus-deepening trochleoplasty with additional MPFL reconstruction. All patients were assessed at a minimum follow-up of 10 years by an independent clinician who noted any patellar redislocation or reoperations in the operated knee and collected the International Knee Documentation Committee (IKDC), Kujala, and satisfaction scores. Furthermore, a radiographic examination was performed to assess patellar height using the Caton-Deschamps index and patellofemoral arthritis using the Iwano classification. Results: At a mean follow-up of 14.8 ± 2.1 years (range, 10-20 years), 4 patients (4 knees) were lost to follow-up (8.3%). The satisfaction, Kujala, and IKDC scores were 8.2 ± 1.6, 77.5 ± 14.4, and 65.7 ± 13.5, respectively. Only 1 patient reported a traumatic patellar dislocation (2%). Radiographs at the final follow-up were available for 34 knees, which revealed Iwano grade 1 in 14 knees (41%), Iwano grade 2 in 7 knees (21%), and no patellofemoral arthritis in 13 knees (38%). Conclusion: Sulcus-deepening trochleoplasty with MPFL reconstruction provides satisfactory results and prevents patellar redislocations with no or minimal patellofemoral arthritis.

Suprapatellar pouch effusion is associated with an increased risk of neglected osteochondral fractures in primary acute traumatic patellar dislocation: a consecutive series of 113 children

BackgroundThe aim of this study was to investigate the risk factors of neglected osteochondral fractures in primary acute traumatic patellar dislocation in the pediatric population.MethodsA total of 113 patients with primary acute traumatic patellar dislocation for whom coincident osteochondral fractures could not be confirmed by X-ray examination at initial diagnosis between January 2010 and February 2022 were retrospectively analyzed. Medical history, physical examination, and radiographic images were recorded in detail. The greatest dimension of the suprapatellar pouch (SP) effusion on radiograph was measured. Computed tomography and magnetic resonance imaging were used to confirm the presence of neglected osteochondral fractures and measure the fragment size. Potential risk factors were calculated and correlated with reference to the neglected osteochondral fractures and fragment size using multivariate linear regression analysis.ResultsWeight, walking ability, effusion grade, and SP measurement had a significant correlation with neglected osteochondral fractures in primary acute traumatic patellar dislocation (p = 0.046; p < 0.001; p = 0.048; p < 0.001). The cutoff point was 53.5 kg for weight and 18.45 mm for SP measurement. In the neglected fractures group, SP measurement was statistically significant with larger fragment size (beta value = 0.457; p < 0.001), and the cutoff point was 26.2 mm.ConclusionsSP effusion is not only associated with an increased risk of neglected osteochondral fractures in primary acute traumatic patellar dislocation but also with larger fragment size. Knee radiograph, medical history, and physical examination can predict the need for further imaging examination and even surgery in primary acute traumatic 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.

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.

Patterns of Associated Knee Ligament and Chondral Injuries in First-Time Traumatic Patellar Dislocation: A Retrospective Magnetic Resonance Imaging (MRI) -Based Study.

Introduction First-time acute traumatic patellar dislocation, when managed without a knee magnetic resonance imaging (MRI) scan, may lead to missed diagnoses of important associated knee injuries. The aim of this study was to ascertain the incidence of associated ligamentous and cartilaginous injuries in first-time traumatic patella dislocation. Methods This was a five-year retrospective study on patients aged 16-45 who had knee MRI scans showing the characteristic bone bruise patterns seen in traumatic lateral patellar dislocation. Anonymized data from the hospital picture archiving and communication system (PACS) was obtained with each scan reviewed by a consultant radiologist, a fellowship-trained orthopaedic knee specialist, and an orthopaedic registrar or resident. Results A total of 200 knee MRI scans were screened. 61 eligible knee MRI scans were included in the study. The patients' ages ranged from 16 to 42 years old, with a mean of 25 years. 73.8% were male. A medial patellofemoral ligament (MPFL) tear or rupture occurred in 58 of 61 knees (95%) with MPFL attenuation in three (5%) injured knees. Meniscal injuries were identified in 5 of 61 knees (8.2%), medial collateral ligament (MCL) injuries in 11 of 61 knees (18%), osteochondral injuries and loose bodies in 17 of 61 knees (27.9%), and anterior cruciate ligament (ACL) injury in one knee (1.6%). Conclusions This single-centre MRI-based study has provided information on the incidence of associated chondral and ligamentous injuries in patients with first-time acute traumatic patellar dislocation. This information will be useful for clinicians when counselling patients and will add to the available literature on this injury. An MRI scan should be obtained in cases of suspected first-time traumatic patellar dislocations, especially in active young patients, due to the incidence of other associated traumatic knee lesions that might need surgical treatment and lead to persisting knee symptoms if neglected.

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).

Outcomes following the operative treatment of intra-articular fracture combined with medial patellofemoral ligament reconstruction after patellar dislocation

PurposeWe examine the outcomes following operative treatment of intra-articular fracture combined with medial patellofemoral ligament (MPFL) reconstruction after patella dislocation.MethodsPatients were retrospectively identified from medical records using diagnostic and surgical procedure codes. Radiological anatomical parameters and bony abnormalities of injured knees were assessed from magnetic resonance images (MRI). Inclusion criteria were traumatic patellar dislocation with chondral or osteochondral fracture and MPFL rupture, operative treatment of a chondral or osteochondral fracture combined with MPFL reconstruction, and minimum follow-up of 2 years. Outcomes were measured using the Kujala score, Tegner activity scale, and the Knee injury and Osteoarthritis Outcome Score Quality-of-Life subscale (KOOS-QLS).ResultsDuring 2012 and 2015, 322 patients were treated because of patellar dislocation. Thirty-three patients had chondral or osteochondral fracture. Eleven patients (five males and six females) with a mean [standard deviation (SD)] age of 17.0 (6.5) years at the time of surgery met the inclusion criteria and were included. Five of the 11 patients had a subchondral and six an osteochondral fracture. Eight patients had a fracture in the patella and three in the femur. All patients had bony abnormalities in the knee. Nine out of 11 patients scored over 90/100 points on the Kujala scale and had good results on the Tegner scale [before surgery 5.0 (2.7) points versus after surgery 5.3 (1.6) points] and the KOOS-QLS [4.1 (4.2) points] outcome measures.ConclusionThe removal or fixation of the fracture fragment combined with MPFL reconstruction is a feasible option in the treatment of symptomatic osteochondral or subchondral fragment in traumatic patellar dislocation. The short-term outcomes are encouraging.Level of evidence: Level IV, retrospective case series.

Medial Patellofemoral Ligament Reconstruction and Osteosynthesis for Traumatic Patellar Dislocation with Patellar Osteochondral Fracture with Open Physes: a Case Report

Medial Patellofemoral Ligament Reconstruction and Osteosynthesis for Traumatic Patellar Dislocation with Patellar Osteochondral Fracture with Open Physes: a Case Report

Surgical treatment of acute patellar dislocation associated with bony avulsion in children

Purpose: The management of acute patellar dislocation in children and adolescents is controversial. Traditionally, most first–time traumatic patellar dislocations have been treated nonoperatively. However, due to new knowledge about medial patellar stabilizers some authors have advocated for surgical repair. The present report describes the mid–term subjective and functional results of operative treatment of acute patellar dislocation in children less than eighteen years of age with concomitant osteochondral fracture.&#x0D; Methods: Data on a cohort of sixteen patients (eight girls and eight boys) aged 14.9 years (mean, range 12–17 years) with acute patellar dislocation were retrospectively collected. Intraarticular fragments were detected in all patients in conventional radiographs. Operative treatment consisted of arthroscopic removal (12 cases) or refixation (4 cases) of the osteochondral fragments and direct repair of the damaged medial patellofemoral ligament (MPFL) if that was still feasible (13 cases). All patients were seen at six months, and a telephone interview with twelve patients (75%) was conducted at four years (mean, range 2–7 years).&#x0D; Results: Of the sixteen patients, two (12.5%) had a recurrent patellar luxation. The subjective IKDC score at the time of the most recent follow–up was 86 (mean, range 63–100), and the Marx Activity Rating Scale score was 9.2 (mean, range 2–16).&#x0D; Conclusions: Direct surgical repair of the injured MPFL may be considered an option to prevent subsequent dislocation and subluxation in first–time traumatic dislocation of the patella in children and adolescents with osteochondral fractures and substantial disruption of medial patellar stabilizers.

Increased tibial tubercle-trochlear groove and patellar height indicate a higher risk of recurrent patellar dislocation following medial reefing

PurposeIdentifying anatomical risk factors on recurrent dislocation after medial reefing is important for deciding surgical treatment. The present study aimed to retrospectively analyze the preoperative magnetic resonance imaging (MRI)-based parameters of patients treated with medial reefing and whether these parameters lead to a higher risk of recurrent dislocation.MethodsFifty-five patients (18.6 ± 6.6 years) who underwent medial reefing after primary traumatic patellar dislocation (84% with medial patellofemoral ligament [MPFL] rupture) were included. Patients were followed up for at least 24 months postoperatively (3.8 ± 1.2 years) to assess the incidence of recurrent patellar dislocation. In patients without recurrent dislocation, the Kujala and subjective IKDC scores were assessed. Moreover, the tibial tubercle-trochlear groove (TT-TG), sulcus angle, patellar tilt, patellar shift, and lateral trochlea index (LTI) were measured. The patellar height was measured using the Caton-Dechamps (CDI), Blackburne-Peel (BPI), and Insall-Salvati index (ISI). The cohort was subclassified into two groups with and without recurrent dislocation. Differences between groups were analyzed with respect to the MRI parameters.ResultsForty percent had a pathological sulcus angle of > 145°, 7.2% had an LTI of < 11°, 47.3% had a patellar tilt of > 20°, and 36.4% had a TT-TG of ≥ 16 mm. Increased patellar height was observed in 34.5, 65.5, and 34.5% of the patients as per CDI, BPI, and ISI, respectively. Nineteen (34.5%) patients suffered from recurrent dislocation. Compared with patients without recurrent dislocation, those with recurrent dislocation had a significantly lower LTI (p = 0.0467). All other parameters were not significantly different between the groups. Risk factor analysis showed higher odds ratios (OR > 2), although not statistically significant, for MPFL rupture (OR 2.05 [95% confidence interval 0.38–11.03], LTI (6.6 [0.6–68.1]), TT-TG (2.9 [0.9–9.2]), and patellar height according to ISI (2.3 [0.7–7.5]) and CDI (2.3 [0.7–7.5])). Patients without recurrent dislocation had a Kujala score of 93.7 ± 12.1 (42–100) points and an IKDC score of 90.6 ± 11.7 (55.2–100) points.ConclusionAnatomical, MRI-based parameters should be considered before indicating medial reefing. A ruptured MPFL, an LTI < 11°, a TT-TG ≥ 16 mm, a patellar tilt > 20 mm, and an increased patellar height according to ISI and CDI were found to be associated, although not significantly, with a higher risk (OR > 2) of recurrent patellar dislocation after medial reefing. Thorough preoperative analysis is crucial to reduce the risk of recurrent dislocation in young patient cohorts.Level of evidenceLevel IV

DOES THE NUMBER OF PATELLOFEMORAL INSTABILITY EPISODES CORRELATE WITH THE PREVALENCE AND SEVERITY OF CHONDRAL AND OSTEOCHONDRAL LESIONS IN PEDIATRIC AND ADOLESCENT PATIENTS?

Disclosures:NoneBackground:Current literature indicates that the risk of chondral and osteochondral injuries following patellofemoral instability events ranges from 40 to 96%. It is unclear based on current literature if there is an association between the number of instability events and the prevalence and severity of chondral and osteochondral injuries.Hypothesis/Purpose:The purpose of this study was to investigate the prevalence and severity of chondral and osteochondral injury following patellar dislocations based on number of dislocations and accounting for other patellofemoral instability risk factors (patella alta, trochlear dysplasia, growth status).Methods:Retrospective chart review was performed for patients under the age of 18 years with a prior history of traumatic patellar dislocation, documented number of instability events, and MRI available for review. Patients were grouped into those with 1 dislocation and >1 dislocation. A priori power analysis based on previous literature demonstrated a required minimum of 82 patients in each group (alpha=.05, power=90%, p1= 70%, p2=90%). Chart review was performed on all patients with diagnosis of patellofemoral instability for past 3 years to determine inclusion and record number of dislocations. MRI and radiographs were independently reviewed by a Musculoskeletal Radiologist and Orthopaedic Surgeon. Chondral injury severity (none, partial thickness, full thickness, osteochondral), location of injury, skeletal maturity, Caton-Deschamps index (CDI), and sulcus angle were recorded. Any discrepancies were settled by review by senior author. Poisson multivariate regression, chi-square, and descriptive statistics were used as appropriate.Results:99 patients were included in each group. There was no statistically significant difference in the prevalence of chondral injury between patients with one dislocation versus more than one dislocation (64.65% versus 55.56%, p=.19) (Table 1). Multivariate regression analysis determined that no factor (patella alta, trochlear dysplasia, skeletal maturity, number of dislocations) was associated with prevalence of chondral injury. Multivariate regression analysis determined patella alta (CDI >1.3) was a significant factor in severity of chondral injury (p=.016).Conclusion:A history of multiple patellar dislocations is not associated with a higher prevalence or increased severity of chondral injury compared to a single patellar dislocation event. In patients with patella alta, a lower threshold for surgical management may be warranted due to its association with more severe cartilage injury, if not already present.Table 1.Demonstrates cartilage injury grouped by number of dislocationsCartilage Injury 1 dislocation>1 dislocationNone35 (35.35%)44 (44.44%)Partial Thickness15 (15.15%)4 (4.04%)Full Thickness13 (13.13%)16 (16.16%)Osteochondral36 (36.26%)35 (35.35%)Any injury64 (64.65%)55 (55.56%)

The majority of patellar avulsion fractures in first-time acute patellar dislocations included the inferomedial patellar border that was different from the medial patellofemoral ligament attachment.

Accurate assessment of the locations of patellar avulsion fractures in acute patellar dislocations is clinically relevant for decision making for treatment. The study aim was to classify the locations of patellar avulsion fractures with a focus on the ligament attachments of medial stabilizing structures. Out of 131 first-time acute traumatic patellar dislocations, 61 patients had patellar fractures. Subsequently, 10 patients with isolated osteochondral fractures of the articular surface in the patella were excluded. Finally, 51 patients (34 females and 17 males, average age: 18.5years, 95% CI 16.1-20.9) were included in the study cohort. Based on the locations of the patellar attachment, the patients were divided into three groups: the superior group [medial patellofemoral ligament (MPFL) attachment], inferior group [medial patellotibial ligament (MPTL)/medial patellomeniscal ligament (MPML) attachment], and mixed group. In the patellar avulsion group (51 patients), the superior group, mixed group, and inferior group contained 8/51 (16%), 12/51 (24%), and 31/51 (61%) patients, respectively. This study showed that 84% of the patellar avulsion fractures were located in the inferomedial patellar border, which consisted of MPTL/MPML attachments that were clearly different from the true "MPFL" attachment at the superomedial patellar border. In terms of the clinical relevance, the acute surgical repair of MPTL/MPML attachments in the inferomedial patellar border may not sufficiently control the patella if optimal management of the MPFL is not performed. IV.

Medial Patellofemoral Ligament Reconstruction in Skeletally Immature Patients.

Patellofemoral instability is a common problem affecting children and adolescents, with recurrent instability often requiring surgical intervention. Medial patellofemoral ligament (MPFL) reconstruction has become a mainstay for the treatment of patellofemoral instability because of the biomechanical importance of the MPFL against lateral dislocation as well as the high frequency of MPFL injury following traumatic patellar dislocation. The concern in managing skeletally immature patients is the potential for injury to the distal femoral physis. Here, we highlight 2 techniques for MPFL reconstruction. The first technique utilizes a hamstring autograft. The steps include: Step 1: Harvest the semitendinosus graft from a 2-cm posteromedial incision with use of an open tendon harvester proximally and a closed tendon harvester distally. Step 2: Prepare the graft for double-bundle reconstruction, allowing for approximately 50 to 60 mm for the reconstructed MPFL and 15 to 20 mm for graft placement within the patella and femoral sockets. Step 3: Use a guidewire and reamer to create 2 patellar sockets approximately 15 mm long each. Step 4: Use a guidewire under fluoroscopy to position and create a femoral socket distal to the distal femoral physis approximately 15 mm long. Step 5: Fix the graft on the femur with use of a tenodesis screw, pass the graft through the soft-tissue space between the fascia and synovium to the superior half of the patella, then dock the free ends of the graft onto the 2 patellar sockets with "PEEK (polyetheretherketone) SwiveLocks (Arthrex)" while the knee is in 30° of flexion. We also review a second technique of docking the hamstring graft onto the adductor tubercle and suturing it proximally to the deep distal medial aspect of the quadriceps tendon. Although only a limited number of studies have reported the outcomes of MPFL reconstruction in skeletally immature patients, such studies have demonstrated a high return to preoperative level of sports activity and a reduced prevalence of recurrent patellar instability.

Anatomical double-bundle medial patellofemoral ligament reconstruction in recurrent patellar dislocation using autologous gracilis tendon graft

Background Recurrent lateral instability of the patella after traumatic patellar dislocation always involves injury to the medial patellar soft tissue restraints. The purpose of the study was to assess the results of double-bundle medial patellofemoral ligament (MPFL) reconstruction in the management of recurrent lateral patellar dislocations. Patients and methods Between January 2012 and November 2014, MPFL reconstruction was performed in 25 knees in 19 patients (12 females and seven males) at Benha University Hospital. The inclusion criteria included patients with recurrent dislocations of the patella (more than two times) with deficient medial retinacula. Autogenous gracilis graft was used as double bundle. Graft was fixed at the femoral side using interference screws and at the patellar side using incomplete tunnels and bone groove in the medial half of the patella. Results Average follow-up period was 32.16±5.8 months. At the final follow-up, average postoperative Lysholm score improved significantly from 58.88±5.87 to 90.68±2.77 (P Conclusion Anatomical double-bundle MPFL reconstruction is a simple and cheap technique used in the current case series that provides accurate femoral and patellar anatomical insertion points at the insertion sites and allows proper tensioning of the graft maintaining normal patellar glide, with overall favorable outcome results.