Clinical and Functional Outcomes of Documented Knee Dislocation Versus Multiligamentous Knee Injury: A Comparison of KD3 Injuries at Mean 6.5 Years Follow-up.

BACKGROUND: Previous research has found that the incidence of neurovascular injury is greatest among multiligamentous knee injuries (MLKIs) with documented knee dislocation (KD). However, it is unknown whether there is a comparative difference in functional recovery based on evidence of a true dislocation. PURPOSE: To determine whether the knee dislocation-3 (KD3) injury pattern of MLKI with documented tibiofemoral dislocation represents a more severe injury than KD3 MLKI without documented dislocation, as manifested by poorer clinical outcomes at long-term follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A multicenter retrospective cohort study was performed of patients who underwent surgical treatment for KD3 MLKI between May 2012 and February 2021. Outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner activity scale, and visual analog scale (VAS) for pain. Documented dislocation was defined as a radiographically confirmed tibiofemoral disarticulation, the equivalent radiology report from outside transfer, or emergency department documentation of a knee reduction maneuver. Subgroup analysis was performed comparing lateral (KD3-L) versus medial (KD3-M) injuries. Multivariable linear regression was conducted to determine whether documented dislocation was predictive of outcomes. RESULTS: A total of 42 patients (25 male, 17 female) were assessed at a mean 6.5-year follow-up (range, 2.1-10.7 years). Twenty patients (47.6%) were found to have a documented KD; they reported significantly lower IKDC (49.9 vs 63.0; P = .043), Lysholm (59.8 vs 74.5; P = .023), and Tegner activity level (2.9 vs 4.7; P = .027) scores than the patients without documented dislocation. VAS pain was not significantly different between groups (36.4 vs 33.5; P = .269). The incidence of neurovascular injury was greater among those with documented dislocation (45.0% vs 13.6%; P = .040). Subgroup analysis found that patients with KD3-L injuries experienced a greater deficit in Tegner activity level than patients with KD3-M injuries (Δ: -3.4 vs -1.2; P = .006) and had an increased incidence of neurovascular injury (41.7% vs 11.1%; P = .042). Documented dislocation status was predictive of poorer IKDC (ß = -2.15; P = .038) and Lysholm (ß = -2.85; P = .007) scores. CONCLUSION: Patients undergoing surgical management of KD3 injuries with true, documented KD had significantly worse clinical and functional outcomes than those with nondislocated joints at a mean 6.5-year follow-up. The current MLKI classification based solely on ligament involvement may be obscuring outcome research by not accounting for true dislocation.

The Surgical Management of NCAA Division 1 College Football Injuries Post COVID-19: A Single Institution Retrospective Review.

ABSTRACT: Cohen, JL, Cade, WH, Harrah, TC, Costello II, JP, and Kaplan, LD. The surgical management of NCAA Division 1 college football injuries post COVID-19: A single institution retrospective review. J Strength Cond Res 38(5): 906-911, 2024-The unprecedented COVID-19 pandemic had a significant impact on college football operations, including athletes' training regimens. As a result of these changes, concern for increased injury susceptibility post COVID-19 regulations has become a point of discussion. The current study sought to evaluate the incidence of surgical injury among NCAA Division 1 college football players at the authors' institution during the first full season after start of the COVID-19 pandemic compared with previous years. Retrospective chart review was performed for all players who sustained injuries requiring surgery while a member of the NCAA Division 1 football program during the 2009-2021 seasons. A p -value of ≤0.05 was used to determine significance. A total of 23 surgical injuries occurred in 22 players during the 2021 season compared with 121 in 118 players in the 12 previous seasons combined ( p = 0.0178; RR = 1.47). There was a significant increase in shoulder injuries ( n = 13 vs. n = 31; p = <0.0001; RR = 3.05) and specifically a significant increase in labral tears ( n = 10 vs. n = 30; p = 0.0003; RR = 2.74). No difference was seen in knee injuries ( n = 10 vs. n = 77; p = 0.27; RR = 1.35) and specifically no difference in anterior cruciate ligament injuries ( n = 3 vs. n = 31; p = 0.77; RR = 1.17). This phenomenon is multifactorial in nature, but alterations to players' training and preparations because of the COVID-19 pandemic likely resulted in suboptimal conditioning, leading to the increased incidence of surgical injuries emphasizing the importance of adequate strength training and conditioning.

The Epidemiology of Posttraumatic Osteoarthritis of the Knee in the United States: An Analysis of 948,853 Patients From 2000 to 2022.

INTRODUCTION: Posttraumatic osteoarthritis of the knee (PTOAK) is a known sequela of bony and soft-tissue articular knee injuries, although its historically reported prevalence is highly variable with no recent population-based studies. METHODS: The TriNetX/US Collaborative Network database was queried to identify adult patients diagnosed with a history of knee trauma using ICD-10-CM coding. Primary outcomes measured were yearly incidence proportion (IP), incidence rate (IR), and prevalence of knee osteoarthritis in the United States from 2000 to 2022. Chi square analyses were conducted to compare outcomes across categorical data. Regression modeling was performed to project PTOAK epidemiology to 2030. Statistical significance was held at P < 0.05 for all analyses. RESULTS: Nine hundred forty-eight thousand eight hundred fifty-three patients meeting criteria were identified. As of 2022, the IP of PTOAK was 5.93%, IR was 2.26 × 10 -4 cases/person-day, and prevalence was 21.1%. By strata in 2022, posttraumatic knee OA is most prevalent among the 54 to 59-year-old age group (50.9%), 60 to 64-year-old age group (50.3%), 50 to 54-year-old age group (49.7%), female patients (24.2%), and White patients (23.1%). Regression analyses revealed that the IP, IR, and prevalence of PTOAK have increased exponentially from 2000 to 2022. By 2030, the model predicts that the IP will further increase to 10.7% (95% PI = 9.79% to 11.7%), IR will be 3.79 × 10 -4 cases/person-day (95% PI = 3.28 × 10 -4 to 4.29 × 10 -4 ), and prevalence of PTOAK in the United States will be 40.6% (95% PI = 39.1% to 42.0%). DISCUSSION: These findings echo earlier, smaller scale studies but reveal an alarming rise in PTOAK prevalence, potentially doubling by 2030. The financial burden of knee OA treatment in the United States is already substantial, costing between $5.7 and $15 billion USD annually. This projected increase in prevalence could further increase healthcare expenditures by $1 to 3 billion by 2030. These results emphasize the need for additional research into factors contributing to PTOAK, evidence-based preventive public health interventions, and the development of multidisciplinary system-based care delivery optimization pathways.

Prevalence and Predictors of Concomitant Meniscal and Ligamentous Injuries Associated With ACL Surgery: An Analysis of 20 Years of ACL Reconstruction at a Tertiary Care Children's Hospital.

BACKGROUND: There is an increasing rate of procedures being performed for concomitant injuries during anterior cruciate ligament (ACL) surgery. Few studies have examined risk factors for these associated injuries in young patients. HYPOTHESIS: There are patient-related factors predictive of concomitant knee pathology that differ between age-based cohorts. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Natural language processing was used to extract clinical variables from available notes of patients undergoing ACL surgery between 2000 and 2020 at a single institution (5174 ACL surgeries; mean age, 17 ± 4 years; 53.1% female; accuracy, >98%). Patients were stratified to pediatric (5-13 years), adolescent (14-19 years), and young adult (20-35 years) cohorts. Logistic regression was used to determine predictors of concomitant injury to the menisci, medial collateral ligament (MCL), posterolateral corner (PLC), and posterior cruciate ligament (PCL). RESULTS: Between 2000 and 2020, 54% of pediatric, 71% of adolescent, and 70% of adult patients had ≥1 concomitant soft tissue injury. In children and adolescents, increased age was consistently predictive of sustaining a concomitant injury (P < .02). Female children had increased odds of concomitant medial meniscal injury, while female adults had decreased odds (P≤ .046). Adolescent and adult female patients had decreased odds of concomitant lateral meniscal injury (P≤ .027). Female children had increased odds of injury to the MCL (P = .015), whereas female children and adolescents had decreased odds of PCL injury (P≤ .044). Adolescents undergoing revision ACL surgery had increased odds of meniscal injury (P≤ .001) and decreased odds of concomitant MCL injury (P = .028). Increased body mass index (BMI) was associated with increased odds of concomitant medial meniscal injury in all cohorts (P≤ .041), lateral meniscal injury in adults (P = .045), and PLC injury in children (P = .016). Contact injuries were associated with increased odds of MCL injury in adolescents (P = .017) and PLC injury in adolescents and adults (P < .014). CONCLUSION: These findings support the hypothesis, as there were multiple factors that significantly affected the risk of concomitant injuries that differed between cohorts. Increased age, BMI, and contact injury history were generally associated with increased odds of sustaining a concomitant injury, whereas female sex and revision ACL surgery had mixed effects. Further studies are essential to investigate the sex-based differences in risk for concomitant injuries and to develop tailored treatment plans that minimize the risk of secondary ACL injury.

Knee, Low Back, and Shoulder Problems Among University and Professional Volleyball Players: Playing With Pain.

CONTEXT: The knee, low back, and shoulder account for most overuse injuries in volleyball. Previous researchers have used methodology that did not examine the extent of injury burden and effect on performance. OBJECTIVE: To develop a more accurate and complete understanding regarding the weekly prevalence and burden of knee, low back, and shoulder problems within the highest levels of men's volleyball, including the role that preseason complaints, match participation, player position, team, and age have on complaints. DESIGN: Descriptive epidemiology study. SETTING: Professional volleyball clubs and the National Collegiate Athletic Association Division I program. PATIENTS OR OTHER PARTICIPANTS: A total of 75 male volleyball players, representing 4 teams playing in their country's respective premier league (Japan, Qatar, Turkey, and the United States), participated over a 3-season period. MAIN OUTCOME MEASURE(S): Players completed a weekly questionnaire (Oslo Sports Trauma Research Centre Overuse Injury Questionnaire) reporting pain related to their sport and the extent to which knee, low back, and shoulder problems affected participation, training volume, and performance. Problems leading to moderate or severe reductions in training volume or performance or the inability to participate were considered substantial problems. RESULTS: The mean weekly prevalence of knee, low back, and shoulder problems based on 102 player-seasons was 31% (95% CI = 28%, 34%), 21% (95% CI = 18%, 23%), and 19% (95% CI = 18%, 21%), respectively. Most players (93%, 95/102 player-seasons) reported some level of knee (79%, n = 81/102 player-seasons), low back (71%, n = 72/102 player-seasons), or shoulder (67%, n = 68/102 player-seasons) complaints during the season. Most players (58%, n = 59/102 player-seasons) experienced at least 1 episode of substantial problems affecting the knee (33%, n = 34/102 player-seasons), low back (27%, n = 28/102 player-seasons), or shoulder (27%, n = 28/102 player-seasons). Players with preseason complaints had more in-season complaints than teammates without preseason problems (mean weekly prevalence: knee, 42% versus 8%, t49 = -18.726, P < .001; low back, 34% versus 6%, t32 = -12.025, P < .001; shoulder, 38% versus 8%, t30 = -10.650, P < .001). CONCLUSION: Nearly all included elite male volleyball players experienced knee, low back, or shoulder problems, and most had at least 1 bout that substantially reduced training participation or sport performance. These findings suggest that knee, low back, and shoulder problems result in greater injury burden than previously reported.

Does playing surface affect the risk of anterior cruciate ligament injuries in the National Football League? A look at the 2017 - 2021 NFL seasons.

BACKGROUND: Anterior cruciate ligament (ACL) injuries are devastating injuries for athletes. Prior studies have shown increased ACL injury rates on non-natural surfaces versus natural grass in several sports. The purpose of this study is to calculate the prevalence of ACL injuries in the NFL on natural versus non-natural surfaces to determine if there is a significant increase on non-natural surfaces. METHODS: Accessing publicly available data for NFL seasons beginning with the 2017-2018 season through 2021-2022 seasons, all ACL injuries with publicly available data concerning timing and playing surface were recorded and categorized according to playing surface. Practice injuries or those without an identifiable playing surface were excluded. Incidence rates, defined as ACL ruptures per game, were calculated. ACL injuries were recorded for each playing surface, as well as the combined category of non-natural grass surface. Odds ratio was calculated to compare the risk of ACL rupture on non-natural surfaces vs natural grass. RESULTS: During the 2017-2021 NFL seasons, 173 ACL ruptures were identified with known surfaces. Injury rate for non-natural surfaces was 0.134 compared to 0.097 for grass. Injury rate ratio for non-natural vs natural grass surfaces was 1.211, a 21.1% increased risk of ACL injury in the NFL on non-natural surfaces vs natural grass. OR for non-natural surfaces 1.239 (95% CI 0.900-1.704). Based on these findings there is a trend toward increased risk of ACL injury on non natural grass surfaces, however this did not reach statistical significance. CONCLUSION: Numerous published studies show trends toward increasing rates of ACL injuries on non-natural playing surfaces vs natural grass. Based on our findings the difference is not statistically significant, however it does trend toward increased risk of ACL injury with non-natural surfaces. Further studies should be performed with larger sample sizes in order to further determine the risk of non-natural surfaces.

Multiligament knee injuries. Ten years' experience at a public university, level I Trauma Center.

PURPOSE: To describe our institutional experience and results in the surgical management of multiligament knee injuries (MLKI). MATERIALS AND METHODS: Retrospective series of MLKI consecutively operated on at a single, level I Trauma Center. Data on patients' baseline characteristics, injuries, treatments, and outcomes were recorded up to one-year follow-up. Recorded outcomes included the Tegner-Lysholm Knee Scoring Scale (TLKSS), return to work, and patient satisfaction. RESULTS: MLKI incidence was 0.03% among 9897 orthopedic trauma admissions. Twenty-four patients of mean age 43.6 years were included in analysis. The mean Injury Severity Score was 12.6. Five patients presented with knee dislocations and six had fracture-dislocations, two of them open fractures. There was one popliteal artery injury requiring a bypass and four common peroneal nerve palsies. Staged ligamental reconstruction was performed in all cases. There were seven postoperative complications. The median TLKSS was 80 and, though patient satisfaction was high, and dissatisfaction was largely restricted to recreational activities (only 58.3% satisfied). Seventeen patients returned to their previous employment. CONCLUSIONS: We found a high aggregation of fracture-dislocations secondary to road traffic accidents. One in four patients experienced complications, particularly stiffness. Complications were more common in cases involving knee dislocation. Most patients had good functional results, but 25% were unable to return to their previous work, which demonstrates the long-lasting sequelae of this injury.

Incidence of postoperative complications in patellar fractures related to different methods of osteosynthesis procedures - a retrospective cohort study.

BACKGROUND: Patellar fractures have a comparatively low incidence compared to all fracture frequencies of the musculoskeletal system. However, surgical management is crucial to prevent postoperative complications that affect the knee joint. The purpose of the present study was to evaluate the incidence of postoperative complications and onset of postoperative osteoarthritis related to the chosen technique of patellar fracture management. METHODS: In a retrospective cohort study consecutive managed, isolated patella fractures were reviewed for demographic data, trauma mechanism, patella fracture type, fixation technique and postoperative complications. The results were documented radiographically and clinically and analysed statistically. The reporting followed the STROBE guidelines. RESULTS: A total of 112 patients were eligible for data evaluation. Surgical management of comminuted patellar fractures with small fragment screws showed significant fewer postoperative complications compared to other fixation techniques (8%, p < 0.043). The incidence of posttraumatic infection was significantly higher following the hybrid fixation technique with cannulated screws and tension wire than following the other analysed techniques (p = 0.024). No postoperative wound infection was observed after screw fixation or locking plate fixation. Symptomatic hardware was most frequently seen after tension-band fixation. Onset of posttraumatic osteoarthritis was most often found after the hybrid fixation technique (55%). CONCLUSION: Surgical management of patellar fractures remains crucial but fracture fixation using plating systems or small fragment screws is least associated with postoperative complications. TRIAL REGISTRATION: Trial registration number (DRKS):00027894.

Pediatric Anterior Cruciate Ligament Reconstruction.

The incidence of anterior cruciate ligament (ACL) injuries in children and adolescents has been growing recently. This problem is a challenge for the treating orthopedic surgeon, especially when the patient is in the prepubertal period with a high growth potential. Since reconstructive procedures require interventions close to active growth plates, they are associated with the risk of postoperative limb length discrepancies and limb deformities. Postponing ACL reconstruction until the end of growth is not a solution, as persistent knee instability increases the risk of secondary intra-articular damage. The key to success is not only knowledge of the anatomy and biomechanics of the pediatric knee but also the ability to predict the remaining growth potential and familiarity with a wide range of reconstructive surgical procedures available for patients at different ages.

Impaction Fractures of the Lateral Femoral Condyle Related to Anterior Cruciate Ligament Injury: A Scoping Review Concerning Diagnosis, Prevalence, Clinical Importance, and Management.

Background: During pivot-shift anterior cruciate ligament (ACL) injury, bone bruises or impaction fractures of the lateral femoral condyle (LFC-IF) may occur due to impaction between the posterior part of the lateral tibial plateau and anterocentral part of the LFC. The purpose of the study was to systematically review the literature concerning the diagnosis, prevalence, clinical importance, and management of LFC-IF occurring during ACL injuries. Methods: Included were studies concerning impaction fractures of the anterocentral part of the LFC occurring during ACL injuries. Studies concerning only bone bruises or cartilage lesions, without subchondral bone impaction, were not included. A search was performed in Medline and Scopus databases, with final search in May 2022. A secondary search was conducted within the bibliographies of included articles and using "Cited In" option. Two authors independently extracted data in three domains: study design, LFC-IF characteristics, and LFC-IF importance and management. Results: A total of 35 studies were included for review with several studies reporting on multiple domains. Summarily, 31 studies were on the diagnosis and prevalence, 19 studies reported on the clinical importance, and 4 studies reported on the management of LFC-IF. Conclusions: A LFC-IF occurs due to the pivot-shift mechanism of ACL injury. Its radiological feature is defined as an impaction of terminal sulcus deeper than 1 mm and is present in up to 52% of patients with a torn ACL. An LFC-IF causes injury to the cartilage, probably leads to its progressive degeneration, and is significantly associated with an increased risk of a lateral meniscus injury. A large LFC-IF might be associated with greater rotational knee instability. Although several techniques of LFC-IF treatment were proposed, none of them has been evaluated on a large cohort of patients to date.

Impact of Environmental Factors on the ACL Injury Risk in Recreational Alpine Skiing.

In recreational alpine skiing, an ACL injury represents the most common injury. Skiing is a complex activity where the skier interacts with the environment, such as weather, snow conditions, temperature, etc. Thus, the aim of this study was to evaluate the potential impact of environmental factors on ACL injury risk in recreational alpine skiers. Among a cohort of 392 ACL-injured skiers and 392 uninjured controls matched for sex and skiing skill, environmental factors were collected by questionnaire. Factors included weather conditions, snow conditions, perceived temperature, and slope difficulty at the time-point of the accident (ACL-injured skiers) or of questioning during the ski day (uninjured controls).Multiple logistic regression revealed that in addition to age, five environmental factors were significantly predictive of an ACL injury: fresh snow (OR 10.5), grippy snow (OR 7.8), icy slope condition (OR 12.4), very cold/cold perceived temperature (OR 1.6), and skiing on easy slopes (OR 6.9). In conclusion, besides age, environmental factors such as fresh and grippy snow, icy slope conditions, low temperatures, and flat slopes are associated with an increased ACL injury risk in recreational alpine skiing. Those factors are at least partly modifiable and should be taken into consideration for preventive strategies.

Orthopaedic knee scooter-related injury: prevalence and patient safety perception in a prospective cohort with exploratory risk factor analysis.

BACKGROUND: There is a paucity of research investigating the harms associated with orthopaedic knee scooter (OKS) use and patient safety perceptions. This prospective study aimed to define the prevalence of OKS-related injuries, describe the patient perceptions of OKS safety, and identify potential risk factors. METHODS: This study was conducted at a single foot and ankle fellowship-trained surgeon's community-based clinic from 6/2020 to 4/2021 and enrolled 134 patients. Our primary outcome was an OKS-related event (injury or fall) and informed an a priori power analysis. Point estimate of association magnitude was calculated as an odds ratio (OR) for statistically and clinically significant associations. RESULTS: There were 118 (88%) patients eligible for analysis; fourteen enrolled patients did not use OKS, and two withdrew. The prevalence of patient falls was 37% (44/118), and the prevalence of patient injury was 15% (18/118). Four percent of patients would not recommend OKS and 8% would not use an OKS again. Sedentary lifestyle increased risk (OR = 4.67, 1.52-14.35 95 CI) for OKS-related injury. CONCLUSIONS: Despite a high prevalence of patient falls (37%), there is a low prevalence of injury (15%) and a favorable perception of OKS safety. Sedentary lifestyles may be a risk factor for OKS-related injury and should be considered in the development of a risk model.

Patient injury claims for posterior cruciate ligament injury: a nationwide registry study in Finland.

BACKGROUND AND PURPOSE: Posterior cruciate ligament (PCL) injuries usually occur in combination with other ligamentous knee injuries. The outcome varies and may be poor due to suboptimal treatment. We investigated claims following PCL injury treatment on a nationwide scale. PATIENTS AND METHODS: All patient PCL injury claims filed in Finland from 1997 to 2015 were collected from the Patient Insurance Centre (PIC) register. We reviewed and analyzed all records to determine the causes of claims. General background data were obtained from the National Care Register for Social Welfare and Health Care (HILMO). RESULTS: We found out from HILMO background data that, during the 19-year study period, 1,891 PCL and 1,380 multiligament reconstructions were performed in 99 different hospitals. The number of PCL injuries treated conservatively is unknown. During this same period, 49 claims arrived at the PIC, and 39/49 of these patients were operated on. 12/49 claims were compensated. Of these 12 claims, 6 were compensated for technical errors and 4 were compensated for diagnostic delays. CONCLUSION: The number of patient injury claims was few, and compensated claims were even fewer. Technical errors and diagnostic delays were the most common reasons for reimbursement.

High prevalence of associated intra-articular injuries with increasing time period from anterior cruciate ligament injury to reconstruction, even in apparent copers.

BACKGROUND: It still unclear whether copers may bear the same time-sensitive risk of intra-articular injury as non-copers. The objectives were to investigate the clinical characteristics of copers and non-copers that have sustained an anterior cruciate ligament (ACL) injury, and to examine and compare the intra-articular pathologies in delayed ACL reconstruction (ACLR) in copers and noncopers. METHODS: Patients who sustained ACL injury while participating in high-performance sports and opted for non-operative treatment were enrolled in this study. Depending on the occurrence of the knee giving way, patients were classified into copers and noncopers. Clinical characteristics were compared between the two groups. Additionally, intra-articular injuries were evaluated for those who eventually underwent delayed ACLR. RESULTS: 11 of the 75 patients (14.7%) were classified as copers. No major differences were found in the clinical characteristics between groups. Following the initial non-operative treatment, 67 patients underwent delayed ACLR. When examining intra-articular abrasions at the time of surgery, non-copers who continued sports activities for 3 to 12 months exhibited a significantly higher rate of injury as opposed to their coper counterparts. However, the difference in the prevalence of intra-articular lesions between the two groups in patients who continued to play sports for at least 12 months before surgery was nominal. CONCLUSION: The rate of copers was relatively low in patients who resumed playing high-level sports after ACL injury. Additionally, even in copers, those who continued sports activities for more than 12 months had comparably high prevalence of intra-articular injuries with noncopers. STUDY DESIGN: Retrospective case-control study; Level of evidence, 3.

Major Increase in Incidence of Pediatric ACL Reconstructions From 2005 to 2021: A Study From the Norwegian Knee Ligament Register.

BACKGROUND: The incidence of pediatric and adolescent anterior cruciate ligament reconstruction (ACLR) is increasing in several countries. It is uncertain whether this trend applies to countries that traditionally prefer an initial nonoperative treatment approach whenever possible, like Norway. Nationwide, long-term patient-reported outcomes and revision rates after ACLR in the pediatric population are also lacking. PURPOSE: To determine the incidence of pediatric ACLR in Norway since 2005, as well as to detect trends in surgical details and describe patient-reported outcomes up to 10 years after ACLR. STUDY DESIGN: Descriptive cohort study. METHODS: This study is based on prospectively collected data on girls ≤14 years and boys ≤16 years, registered in the Norwegian Knee Ligament Register at the time of their primary ACLR, between 2005 and 2021. The main outcome was the incidence of ACLR, adjusted to the corresponding population numbers for each year. The time trend was analyzed by comparing the mean of the first and last 3-year period (2005-2007 and 2019-2021). Patient-reported outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score preoperatively and at 2, 5, and 10 years postoperatively. RESULTS: A total of 1476 patients (1484 cases) were included, with a mean follow-up of 8.1 years (range, 1-17). The incidence of pediatric ACLRs per 100,000 population increased from 18 to 26, which corresponds to an increase of 40% for boys and 55% for girls. Concurrent meniscal procedures increased significantly from 45% to 62%, and the proportion of meniscal repairs increased from 19% to 43% when comparing the first and last time period. The mean Knee injury and Osteoarthritis Outcome Score values for the Sport and Recreation and Quality of Life subscales were between 72 and 75 at the 2-, 5- and 10-year follow-up. The 5-year revision rate was 9.9%. CONCLUSION: There was a major increase in incidence of pediatric ACLR in Norway during the study period. There was a shift in the approach to concomitant meniscal procedures from resection to repair, with more than a doubling of the proportion of meniscal repairs. Patient-reported outcomes revealed long-lasting reduced knee function.

Delaying ACL reconstruction is associated with increased rates of medial meniscal tear.

PURPOSE: The aim of this study was to evaluate the relationship between the time from injury to ACL reconstruction (ACLR) and the rate as well as repairability of meniscal tears. Secondary aims were to evaluate the relationship between meniscal injury and Tegner Activity Scale, age, BMI, and gender. METHODS: Between 2012 and 2022, 1,840 consecutive ACLRs were performed. A total of 1,317 ACLRs were included with a mean patient age of 31.2 years ± 10.5 [16-60]. Meniscal tear was assessed during arthroscopy using the ISAKOS classification. Time from injury to ACLR, Tegner Activity Scale, age, BMI and gender were analysed in uni- and then in multivariate analyses. Patients were divided into four groups according to the time from injury to surgery: < 3 months (427; 32%), 3-6 months (388; 29%), 6-12 months (248; 19%) and > 12 months (254; 19%). RESULTS: Delaying ACLR > 12 months significantly increased the rate of medial meniscal (MM) injury (OR 1.14; p < 0.001). No correlation was found between a 3- or 6-month time from injury to surgery and MM tear. Performing ACLR > 3, 6, or 12 months after injury did not significantly increase the rate of lateral meniscal (LM) injury. Increasing Tegner activity scale was significantly associated with a lower rate of MM injury (OR 0.90; p = 0.020). An age > 30 years (OR 1.07; p = 0.025) and male gender (OR 1.13; p < 0.0001) was also associated with an increased rate of MM injury. Age > 30 years decreased the rate of MM repair (OR 0.85; p < 0.001). Male gender increased the rate of LM tear (OR 1.10; p = 0.001). CONCLUSION: Performing ACLR more than 12 months after injury was associated with increased rates of MM injury but not with lower rates of repairable lesions. An increased pre-injury Tegner activity score was associated with a decreased rate of MM tear. Age > 30 years was associated with an increased rate of MM tear with concomitant ACL injury and a decreased rate of repairability of MM tear. ACLR should be performed within 12 months from injury to prevent from the risk of MM injury. LEVEL OF EVIDENCE: Level III.

Knee injury and osteoarthritis outcome score (KOOS) - National record-based reference values.

BACKGROUND: Knee Injury and Osteoarthritis Outcome Score (KOOS) and the short form KOOS-12 are commonly used in clinical practice and research but there are no national record-based reference values to aid interpretation. The aim of this study was to establish national record-based reference values for the KOOS and its short form KOOS-12. PATIENTS AND METHODS: A national record-based representative sample of 9996 adult citizens were derived from the Danish Civil Registration System. The selection of citizens was based on seven predefined age groups with an equal sex distribution across each age strata. The KOOS questionnaire was sent to all participants, together with two supplemental questions regarding previous knee problems and body mass index (BMI). RESULTS: A total of 2842 participants completed the KOOS, 1463 women (51.4%) and 1379 men (48.6%). The mean KOOS subscale scores were: pain 85.3 (95% confidence interval (CI): 84.6-85.9), symptoms 85.1 (95% CI: 84.5-85.8), activities of daily living (ADL) 86.7 (95% CI: 86.0-87.3), sport and recreation function 70.9 (95% CI: 69.8-72.0), quality of life (QOL) 74.9 (95% CI: 73.9-75.8).Age- and sex-specific reference values showed small differences in mean scores between the five KOOS subscales and all were below the threshold for clinically relevant improvement (10 points).Knee problems were associated with worse KOOS scores across all subscales. The difference in the mean subscale scores between the lowest (<24.9) and highest (>40) BMI groups ranged from 12.9 to 24.1. Comparable results were observed for KOOS-12. CONCLUSION: KOOS and KOOS-12 reference values can, in most situations, be used without stratification for age and sex. Sport/recreation reference values stratified for age and BMI may be of importance.

Return to Sport After Knee Injuries in Collegiate Wrestling.

Background: Wrestling is known to be a sport of relatively high injury incidence, and knee injuries account for a large percentage of those injuries. Treatment of these injuries varies considerably depending on injury and wrestler characteristics, leading to variability in complete recovery and return to sport (RTS). The purpose of this study was to evaluate injury trends, treatment strategies, and RTS characteristics after knee injuries in competitive collegiate wrestling. Methods: NCAA Division I collegiate wrestlers who sustained knee injuries between January 2010 and May 2020 were identified using an institutional Sports Injury Management System (SIMS). Wrestling-related knee, meniscus, and patella injuries were identified, and treatment strategies were documented to investigate potential recurrent injury trends. Descriptive statistics were used to quantify the number of days, practices, and competitions missed, return to sport times, and recurrent injuries among wrestlers. Results: Overall, 184 knee injuries were identified. After excluding non-wrestling injuries (n=11), 173 injuries remained (77 wrestlers). The mean age at time of injury was 20.8 ± 1.4 years, and the mean BMI was 25.9 ± 3.8 kg/m2. There were 135 primary injuries (74 wrestlers), which consisted of 72 (53%) ligamentous injuries, 30 (22%) meniscus injuries, 14 patellar injuries (10%), and 19 other injuries (14%). The majority of ligamentous injuries (93%) and patellar injuries (79%) were treated non-operatively, while the majority of meniscus tears (60%) underwent surgery. Twenty-three wrestlers (22%) sustained recurrent knee injuries, of which 76% were treated non-operatively after their initial injury. Recurrent injuries consisted of 12 (32%) ligamentous injuries, 14 (37%) meniscus injuries, eight (21%) patellar injuries, and four (11%) other injuries. Fifty percent of recurrent injuries were treated operatively. When comparing recurrent injuries to primary injuries, recurrent injuries had a significantly longer return to sport time (Recurrent 68.3 ± 96.0 days vs. Primary 26.0 ± 56.4 days, p=0.01). Conclusion: The majority of NCAA Division I collegiate wrestlers who sustained knee injuries were initially treated non-operatively, and approximately one in five wrestlers sustained recurrent injuries. Return to sport time was significantly increased after a recurrent injury. Level of Evidence: IV.

Delayed multiligament PCL reconstruction is associated with a higher prevalence of intraarticular injury and may influence treatment.

BACKGROUND: The aim of this study was to investigate differences in concomitant injury patterns and their treatment in patients undergoing early (≤ 12 weeks) and delayed (> 12 weeks) primary multiligament posterior cruciate ligament (PCL) reconstruction (PCL-R). METHODS: This study was a retrospective chart review of patients undergoing primary multiligament PCL-R at a single institution between 2008 and 2020. Multiligament PCL-R was defined as PCL-R and concurrent surgical treatment of one or more additional knee ligament(s). Exclusion criteria included isolated PCL-R, PCL repair, and missing data for any variable. Patients were dichotomized into early (≤ 12 weeks) and delayed (> 12 weeks) PCL-R groups based on the time elapsed between injury and surgery. Between-group comparison of variables were conducted with the Chi-square, Fisher's exact, and independent samples t-tests. RESULTS: A total of 148 patients were eligible for analysis, with 57 (38.5%) patients in the early and 91 (61.1%) patients in the delayed multiligament PCL-R groups. Concomitant LCL/PLC reconstruction (LCL-R/PLC-R) was performed in 55 (60%) of delayed multiligament PCL-Rs and 23 (40%) of early PCL-Rs (p = 0.02). Despite similar rates of meniscus injury, concomitant meniscus surgery was significantly more prevalent in the early (n = 25, 44%) versus delayed (n = 19, 21%) multiligament PCL-R group (p = 0.003), with a significantly greater proportion of medial meniscus surgeries performed in the early (n = 16, 28%) compared to delayed (n = 13, 14%) PCL-R group (p = 0.04). The prevalence of knee cartilage injury was significantly different between the early (n = 12, 24%) and delayed (n = 41, 46%) multiligament PCL-R groups (p = 0.01), with more frequent involvement of the lateral (n = 17, 19% vs. n = 3, 5%, respectively; p = 0.04) and medial (n = 31, 34% vs. n = 6, 11%, respectively; p = 0.005) femoral condyles in the delayed compared to the early PCL-R group. CONCLUSIONS: Given higher rates of chondral pathology and medial meniscus surgery seen in delayed multiligament PCL-R, early management of PCL-based multiligament knee injury is recommended to restore knee stability and potentially prevent the development of further intraarticular injury. LEVEL OF EVIDENCE: Level III.

Lifetime risk and genetic predisposition to post-traumatic OA of the knee in the UK Biobank.

OBJECTIVE: Acute knee injury is associated with post-traumatic OA (PTOA). Very little is known about the genome-wide associations of PTOA when compared with idiopathic OA (iOA). Our objective was to describe the development of knee OA after a knee injury and its genetic associations in UK Biobank (UKB). DESIGN: Clinically significant structural knee injuries in those ≤50 years were identified from electronic health records and self-reported data in 502,409 UKB participants. Time-to-first knee osteoarthritis (OA) code was compared in injured cases and age-/sex-matched non-injured controls using Cox Proportional Hazards models. A time-to-OA genome-wide association study (GWAS) sought evidence for PTOA risk variants 6 months to 20 years following injury. Evidence for associations of two iOA polygenic risk scores (PRS) was sought. RESULTS: Of 4233 knee injury cases, 1896 (44.8%) were female (mean age at injury 34.1 years [SD 10.4]). Over a median of 30.2 (IQR 19.5-45.4) years, 1096 (25.9%) of injured cases developed knee OA. The overall hazards ratio (HR) for knee OA after injury was 1.81 (1.70,1.93), P = 8.9 × 10-74. Female sex and increasing age at injury were associated with knee OA following injury (HR 1.15 [1.02,1.30];1.07 [1,07,1.07] respectively). OA risk was highest in the first 5 years after injury (HR 3.26 [2.67,3.98]), persisting for 40 years. In 3074 knee injury cases included in the time-to-OA GWAS, no variants reached genome-wide significance. iOA PRS was not associated with time-to-OA (HR 0.43 [0.02,8.41]). CONCLUSIONS: Increasing age at injury and female sex appear to be associated with future development of PTOA in UKB, the risk of which was greatest in the 5 years after injury. Further international efforts towards a better-powered meta-analysis will definitively elucidate genetic similarities and differences of PTOA and iOA.