Anterior ankle impingment syndrome is less frequent, but associated with a longer absence and higher re-injury rate compared to posterior syndrome: a prospective cohort study of 6754 male professional soccer players.

PURPOSE: To study the epidemiology and return to play characteristics of anterior and posterior ankle impingement syndromes (AAIS and PAIS) over 18 consecutive seasons in male professional soccer players. METHODS: Between the 2001-2002 and 2018-2019 seasons, 120 European soccer teams were followed prospectively for various seasons. Time loss injuries and player exposures were recorded individually in 6754 unique players. Injury incidence and burden were reported as the number of injuries and days absence per 1000 h with 95% confidence intervals (CIs). Injury severity was reported as median absence in days with the interquartile range (IQR). RESULTS: Out of 25,462 reported injuries, 93 (0.4%) were diagnosed as AAIS (38%) or PAIS (62%) in 77 players. AAIS and PAIS were similar regarding injury characteristics except for a greater proportion of AAIS having a gradual onset (69% vs.47%; P = 0.03) and being re-injuries (31% vs. 9%; P = 0.01). Impingement syndromes resulted in an overall incidence of 0.03 injuries (95% CI 0.02-0.03) per 1000 h and an injury burden of 0.4 absence days per 1000 h. PAIS incidence was significantly higher than that for AAIS [0.02 (95% CI 0.002-0.03) vs. 0.01 (95% CI 0.005-0.01) injuries per 1000 h (RR = 1.7). The absence was significantly longer in AAIS than in PAIS [10 (22) vs. 6 (11) days; P = 0.023]. Impingement syndromes that presented with a gradual onset had longer absences in comparison to impingement with an acute onset [8 (22) vs. 5 (11) days; P = 0.014]. Match play was associated with a higher incidence and greater injury burden than training: 0.08 vs. 0.02 injuries per 1000 h (RR 4.7), respectively, and 0.9 vs. 0.3 days absence per 1000 h (RR 2.5). CONCLUSION: Ankle injuries are frequent in men's professional soccer and ankle impingement is increasingly recognized as a common source of pain, limited range of motion, and potential time loss. In our study, ankle impingement was the cause of time loss in less than 0.5% of all injuries. PAIS was more frequently reported than AAIS, but AAIS was associated with more absence days and a higher re-injury rate than PAIS. The findings in this study can assist the physician in best practice management on ankle impingment syndromes in professional football. LEVEL OF EVIDENCE: II.

Exercise-based rehabilitation reduces reinjury following acute lateral ankle sprain: A systematic review update with meta-analysis.

RESEARCH QUESTIONS: 1) Do exercise-based rehabilitation programs reduce re-injury following acute ankle sprain?; 2) Is rehabilitation effectiveness moderated by the exercise's therapeutic quality, content and volume? METHODS: This systematic review with meta-analysis (PROSPERO: CRD42020210858) included randomized controlled trials in which adults who sustained an acute ankle sprain received exercise-based rehabilitation as an intervention. Databases CINAHL, Web of Science, SPORTDiscus, Cochrane Central Register of Controlled Trials, PEDro and Google Scholar were searched for eligible articles (last search: March 2021). ROB II screening tool by Cochrane was used to assess risk of bias and the i-CONTENT tool was used to assess quality of interventions. Both qualitative analysis and quantitative data synthesis were performed. RESULTS: Fourteen randomized controlled trials comprising 2182 participants were included. Five studies were judged overall low risk of bias and i-CONTENT assessment showed poor to moderate therapeutic quality of exercise across all included articles. Pooled data found significant reductions in re-injury prevalence at 12 months, in favour of the exercise-based rehabilitation group vs usual care (OR: 0.60; 95%CI: 0.36 to 0.99). Pooled data for re-injury incidence showed not-significant results (MD: 0.027; 95%CI: -2.14 to 2.19). Meta-regression displayed no statistically significant association between training volume and odds of re-injury (r = -0.00086; SD: 0.00057; 95%CI: -0.00197 to 0.00025). Results from patient-reported outcomes and clinical outcomes were inconclusive at 1 month, 3-6 months and 7-12 months of follow up. CONCLUSION: Exercise-based rehabilitation reduces the risk of recurrent ankle sprain compared to usual care, but there is insufficient data to determine the optimal content of exercise-based interventions. Training volume varied considerably across studies but did not affect the odds of sustaining a re-injury. Effects on patient-reported outcomes and clinical outcomes are equivocal. Future research should compare different exercise contents, training volumes and intensities after ankle sprain.

Factors associated with injury and re-injury occurrence in female pole dancers.

The aim of the study was to recognise what participant-, training- and post-injury-related factors are associated with an injury and re-injury occurrence in female pole dancers (PDs). 320 female PDs fulfilled a custom survey. 1050 injuries were reported by 276 PDs, 59% of injuries were related to lower extremity, 39% to upper extremity and 10% to spine and trunk. 156 PDs reported sustaining a re-injury, and overall, 628 re-injuries were reported. The median weekly pole-specific training session volume was 90 min and 240 min in the low and high qualified group, respectively. The total training volume was 180 min in the low qualified PDs and 240 min in the high qualified group. PDs with higher height and spending more time on pole-specific training in studio and on other forms of training have higher odds of sustaining an injury. PDs with lower level of experience in training, who sustained an injury, and who had a shorter pause between the moment of injury and the return to performance, and thus who did not fully recover, have higher odds of sustaining a re-injury. Sport-specific injury prevention strategies should be developed and implemented in this cohort, since over 85% of pole dancers reported sustaining some kind of injury.

Dance Exposure, Individual Characteristics, and Injury Risk over Five Seasons in a Professional Ballet Company.

PURPOSE: This study aimed to describe the relationships between dance exposure, dancer characteristics, and injury risk across five seasons in a professional ballet company. METHODS: Dance exposure time and clinician-reported time-loss and medical attention injury data were prospectively collected from 118 professional dancers of The Royal Ballet between 2015/2016 and 2019/2020. Cox proportional hazards and shared frailty models were fitted to overuse and traumatic injuries; individualized robust Z-scores for 7- and 28-d accumulated exposure, and week-to-week change in exposure, age, sex, company rank, and injury history were included as time-varying covariates. RESULTS: Across 381,710 h of exposure, 1332 medical attention and 427 time-loss injuries were observed. Positive relationships were observed between week-to-week change in exposure and overuse time-loss (+1 Z-score hazard ratio (HR), 1.27; 95% confidence interval (CI), 1.06-1.53) and medical attention injury risk (+1 Z-score HR, 1.17; 95% CI, 1.06-1.28). A negative relationship was observed between 7-d accumulated exposure and overuse medical attention injury risk (+1 Z-score HR, 0.74; 95% CI, 0.66-0.84). Overuse time-loss injury risk was greater in soloists compared with the corps de ballet (HR, 1.47; 95% CI, 1.01-2.15) and in dancers with a higher previous injury rate (+1 injury per 1000 h HR, 1.06; 95% CI, 1.02-1.10). Only age was associated with traumatic time-loss (+1-yr HR, 1.05; 95% CI, 1.01-1.09) or medical attention injury risk (+1-yr HR, 1.04; 95% CI, 1.01-1.07). CONCLUSIONS: Professional ballet companies should implement training principles such as periodization and progression, particularly in the case of senior-ranking dancers, older dancers, and dancers with high rates of previous injury. These findings provide a basis for future prospective investigations into specific causal injury pathways.

Single season re-injury risk after concussion and lower extremity injury among male, collision sport, high school athletes.

OBJECTIVES: Research suggests that a recent concussion increases subsequent lower extremity injury risk; however, data in high school athletes is limited. This study evaluates the association between concussion and subsequent injury risk among male, collision sport, high school athletes over a single season. DESIGN: Retrospective cohort study. METHODS: Data were obtained from 2005/06-2014/15 in the High School Reporting Information Online database. A two stage, multi-method matching process was used to identify athletes who suffered multiple injuries over a single athletic season. Demographics and injury characteristics were compared with Chi square and Student's t-tests. Multiple Cox Proportional Hazards regression analysis was used to test whether index injury type was associated with hazard of subsequent injury following return to play from index injury. RESULTS: Overall 1364 HS athletes sustained 2 injuries over a single athletic season (subsequent injury within 45 days of the index injury). Index injuries included 686 (50.2%) lower extremity injuries, 417 (30.6%) upper extremity injuries, and 261 (19.1%) concussions. Hazard of subsequent concussion was increased in the index concussion group relative to the index lower extremity injury group [hazard ratio (HR): 1.60, 95% CI: 1.15-2.23, p = 0.0052]. Hazard of a subsequent lower extremity injury was not significantly different for the index lower extremity injury group relative to the index concussion group [HR: 1.27, 95% CI: 0.98-1.65, p = 0.0728]. CONCLUSIONS: History of recent concussion or recent lower extremity injury are both risk factors for subsequent lower extremity injury in male, collision sport, high school athletes.

Does sex affect second ACL injury risk? A systematic review with meta-analysis.

OBJECTIVE: To determine sex-based differences in risk of a second ACL injury (overall and by laterality) following primary ACL reconstruction in athletes who are attempting to return to sport. DESIGN: Systematic review with meta-analysis. DATA SOURCES: Systematic search of five databases conducted in August 2019. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies reporting sex-based differences in the incidence of second ACL injury in athletes attempting to return-to-sports and who were followed for at least 1 year following primary ACL reconstruction. RESULTS: Nineteen studies were included in this review, with seven studies excluded from the primary meta-analysis due to high risk of bias. The remaining 12 studies (n=1431 females, n=1513 males) underwent meta-analysis, with all 19 studies included in a sensitivity analysis. Total second ACL injury risk was 21.9% (females: 22.8%, males: 20.3%). Females were found to have 10.7% risk of an ipsilateral ACL injury and 11.8% risk of a contralateral ACL injury. Males were found to have 12.0% risk of an ipsilateral ACL injury and 8.7% risk of a contralateral ACL injury. No statistically significant differences were observed for total second ACL injury risk (risk difference=-0.6%, 95% CI -4.9 to 3.7, p=0.783, I2=41%) or contralateral ACL injury risk (risk difference=1.9%, 95% CI -0.5% to 4.4%, p=0.113, I2=15%) between sexes. Females were found to have a 3.4% absolute risk reduction in subsequent ipsilateral ACL injury risk compared with males (risk difference=-3.4%, 95% CI -6.7% to -0.02%, p=0.037, I2=35%). CONCLUSION: Both sexes have >20% increased risk of experiencing a second ACL injury. Any difference in the absolute risk of either a subsequent ipsilateral or contralateral ACL injury between sexes appears to be small. REGISTRATION: PROSPERO (CRD42020148369).

Both open and endoscopic gluteal tendon repairs lead to functional improvement with similar failure rates: a systematic review.

IMPORTANCE: Operative treatment of gluteal tendon tears is becomingly increasingly more common with varying surgical techniques and rehabilitation protocols. OBJECTIVE: To perform a systematic review of gluteal tendon repair as it relates to tear characteristics, rehabilitation protocols, patient-reported outcomes, satisfaction, resolution of gait deviation and complication rates. EVIDENCE REVIEW: A comprehensive literature search of PubMed and Embase/MEDLINE was used to identify all literature pertaining to gluteal tendon repair. A total of 389 articles were identified. FINDINGS: A total of 22 studies (611 hips) were included in this review. The majority of tears were noted to be partial thickness (77.9% vs 22.1%). Both arthroscopic and open repair demonstrated improvements in functional outcomes. Within studies documenting gait deviation, 54% were noted to have gait deviation preoperatively, of which approximately 70% had resolution following repair. On average, abduction strength increased almost one whole grade (0.84) following repair. Overall complication rate was found to be 5.2% (20 of 388 hips). Endoscopic repair demonstrated a decreased complication rate compared with open (0.7% vs 7.8%). Retear rate was found to be 3.8%, with open repair having a slightly increased rate compared with endoscopic repair (3.4% vs 4.1%). CONCLUSIONS AND RELEVANCE: The majority of tears tend to be partial thickness with involvement of gluteus medius in almost all cases and concomitant involvement of gluteus minimus in close to half of cases. Both endoscopic and open gluteal tendon repairs resulted in improvements in outcomes and functional improvement. Retear rates were similar between the two repair techniques, while endoscopic repair demonstrated a lower complication rate. LEVEL OF EVIDENCE: Level IV, systematic review.

Age, rehabilitation and surgery characteristics are re-injury risk factors for adolescents following anterior cruciate ligament reconstruction.

OBJECTIVES: To examine the effect of age on post-ACLR rehabilitative outcomes and identify surgical/rehabilitative characteristics as ACL re-injury risk factors in adolescents. DESIGN: Cohort study. SETTING: Children's hospital. PARTICIPANTS: 273 adolescents with first-time ACLR. MAIN OUTCOME MEASURES: Demographics, injury history, surgery, and outcomes documented during post-ACLR physical therapy (PT) sessions were extracted from medical records. Effects of age on outcomes were examined using multivariate regression. ACL re-injury risk factors were identified using survival analysis with Cox regression. RESULTS: Re-injury was recorded in 47 patients (17.2%) with a median follow-up time of 3.1 years and median re-injury time of 13.4 months post-surgery. Younger age (Hazard-Ratio, HR = 1.264 per year decrease; P = 0.005), receiving surgery within 1 month post-injury (HR = 3.378 vs. >3 months; P = 0.012), starting PT within 3 days post-surgery (HR = 3.068; P = 0.022), and decreased number of PT sessions (HR = 1.118 per 3-session decrease; P = 0.010) increased re-injury risk. Although age was associated with re-injury risk, age was not associated with any outcome (P > 0.059). CONCLUSION: Adolescents who are younger, receive surgery and post-surgery PT sooner, or attend fewer PT sessions may be at an increased re-injury risk. Younger patients achieved similar outcomes despite elevated re-injury risk. Current discharge criteria are inadequate in identifying high re-injury risk patients.

Repair of high-grade partial thickness supraspinatus tears after surgical completion of the tear have a lower retear rate when compared to full-thickness tear repair.

PURPOSE: High-grade partial thickness rotator cuff tears (i.e., those involving at least 50% of the tendon thickness) are especially challenging to treat and various treatment strategies have been described. Prior studies have demonstrated equivalent outcomes between in situ tear fixation and tear completion repair techniques. However, it is unknown how repair of completed high-grade partial thickness tears to full tears compares to repair of full-thickness tears. The purpose of this study was to compare clinical outcome measures at least 1 year postoperatively between patients who had completion of a high-grade partial thickness supraspinatus tear to a full-thickness tear (PT) and those who had an isolated full-thickness supraspinatus tear (FT). The hypothesis of this study was equivalent retear rates as well as equivalent clinical and patient-reported outcomes between the two groups. METHODS: A retrospective review of 100 patients who underwent isolated arthroscopic supraspinatus repair between 2013 and 2018 with a minimum of 1 year follow-up was performed. Patients were separated into two groups based on their treatment: 56 had completion of a partial thickness supraspinatus tear to full-thickness tear with repair (PT) and 44 had isolated full-thickness supraspinatus repairs (FT). The primary outcome was rotator cuff retear, which was defined as a supraspinatus retear requiring revision repair. Secondary outcomes were patient-reported outcome measures (PROs) including visual analog pain scale (VAS) and subjective shoulder value (SSV), range of motion (ROM) and strength in forward flexion (FF), external rotation (ER), and internal rotation (IR). RESULTS: There was a significantly lower rate of retear between the PT versus FT groups (3.6% vs. 16.3%, p = 0.040). There were no significant differences between groups for all PROs, all ROM parameters, and all strength parameters (all n.s.). DISCUSSION: The data from this study demonstrated that the PT group had a significantly lower retear rate at 1 year follow-up than the FT group, while PROs, ROM, and strength were similar between the two groups. Patients with PT supraspinatus tears can have excellent outcomes, equivalent to FT tears, after completion of the tear, and subsequent repair with low retear rates. These findings may aid the treating surgeon when choosing between in situ fixation of the PT supraspinatus tear or completion of the tear and subsequent repair, as it allows the treating surgeon to choose the procedure based on comfort and experience level. LEVEL OF EVIDENCE: Level III.

Risk Factors for Failure of Cast Treatment in Displaced Pediatric Tibial Shaft Fractures.

BACKGROUND: As there is a current increasing tendency to treat displaced tibial shaft fractures in adolescents surgically, it has become more important to predict failure of cast treatment for these patients. In the past, redisplacement of pediatric tibial shaft fractures has been reported at rates of 20% to 40%. Although the efficacy of the three-point index (TPI), gap index, and cast index has been demonstrated for upper extremity fractures in children, to date no index has been shown to accurately predict redisplacement for pediatric tibial shaft fractures. The aim of this study was to determine the predictive factors for redisplacement in pediatric tibial shaft fractures. METHODS: In all, 157 displaced pediatric tibial shaft fractures were evaluated retrospectively. Patient age, initial and postreduction fracture angulation, shortening and translation, quality of reduction, obliquity of fracture, associated fibular fractures, and 3 indices (TPI, cast index, and gap index) were analyzed. Receiver operating characteristic analysis was performed to determine the cutoff points and logistic regression was used to show the risk factors of redisplacement. RESULTS: There were 53 female and 104 male patients with a mean age of 9.1 (5 to 15 y) and 45 patients developed redisplacement during the follow-up. Mean TPI and gap index and initial and postreduction fracture translation were higher in patients with redisplacement, while TPI>0.855 and postreduction translation >18% were the only independent risk factors for fracture redisplacement. No differences were observed regarding associated fibular fracture, quality of reduction, initial/postreduction angulation, and shortening. CONCLUSIONS: The TPI>0.855 and postreduction translation >18% are independent risk factors for redisplacement of tibial shaft fractures in children. Although the gap index can be useful, the cast index is not an appropriate tool for these fractures.

Recreational Runners With a History of Injury Are Twice as Likely to Sustain a Running-Related Injury as Runners With No History of Injury: A 1-Year Prospective Cohort Study.

OBJECTIVES: To investigate (1) the cumulative incidence proportion and the most common anatomical locations of running-related injuries in recreational runners, and (2) the associations between running-related injuries and previous injury, running experience, weekly running distance, age, sex, and body mass index. DESIGN: A 1-year prospective cohort study. METHODS: Two hundred twenty-four recreational runners (average weekly running distance for the past 12 months, 15 km) were included (89 women, 135 men). Pain information was reported weekly for 1 year, and all running-related injuries that resulted in time loss or medical consultation were recorded. We accounted for censoring when calculating cumulative incidence proportion, and used crude Cox proportional hazards regression to evaluate whether the variables of interest were associated with running-related injuries. RESULTS: The 1-year cumulative incidence proportion of running-related injuries was 45.9% (95% confidence interval [CI]: 38.4%, 54.2%). The most common anatomical locations were the knee (20/75, 27%) and Achilles tendon/calf (19/75, 25%). Previous injury was associated with a higher injury rate (hazard rate ratio = 1.9; 95% CI: 1.2, 3.2), while the other variables had no statistically significant association with injury. CONCLUSION: There were 75 running-related injuries during the 1-year surveillance period, for a cumulative incidence proportion of 46%. The most common injuries were to the knee and Achilles tendon/calf. Recreational runners with a previous injury were twice as likely to sustain a running-related injury as runners with no previous injury. J Orthop Sports Phys Ther 2021;51(3):144-150. Epub 25 Dec 2020. doi:10.2519/jospt.2021.9673.

Reduced 2-D Frontal Plane Motion During Single-Limb Landing Is Associated With Risk of Future Anterior Cruciate Ligament Graft Rupture After Anterior Cruciate Ligament Reconstruction and Return to Sport: A Pilot Study.

OBJECTIVES: To evaluate the association between 2-D frontal plane movement and second anterior cruciate ligament (ACL) injury risk in young athletes at return to sport (RTS) after ACL reconstruction. DESIGN: Prospective cohort. METHODS: Forty-nine participants who had ACL reconstruction (mean ± SD age, 16.5 ± 3.0 years) performed a single-leg drop landing from a 31-cm box at the time of their RTS. Frontal plane trunk, pelvis, and knee angles were measured using 2-D video analysis at the point of maximum depth during landing. Summated frontal plane angles were calculated by adding trunk, pelvis, and knee angles. Participants were grouped based on whether or not they sustained an ACL graft rupture over the 24 months after RTS. RESULTS: Seven participants (14%) sustained an ipsilateral graft rupture within 24 months after RTS. Participants who suffered a second ACL injury had a significant reduction in the summated frontal plane angle of the trunk, pelvis, and knee (P = .018) and of the trunk and knee (P = .02) compared to those who did not suffer a second injury. For every 5° increase in the summated trunk, pelvis, and knee angle (odds ratio [OR] = 0.54; 95% confidence interval [CI]: 0.31, 0.94) and the summated trunk and knee angle (OR = 0.48; 95% CI: 0.25, 0.94), the athletes were 46% to 52% less likely to sustain a graft rupture. CONCLUSION: Athletes who suffered an ACL graft rupture within 24 months of RTS had a more rigid posture when landing compared to their uninjured peers. The results of this pilot study should be replicated in a larger sample to determine whether this method has merit as a screening tool to identify athletes at high risk for second ACL injury. J Orthop Sports Phys Ther 2021;51(2):82-87. Epub 25 Dec 2020. doi:10.2519/jospt.2021.9302.

Footprint preparation with nanofractures in a supraspinatus repair cuts in half the retear rate at 1-year follow-up. A randomized controlled trial.

PURPOSE: To evaluate if adding nanofractures to the footprint of a supraspinatus tear repair would have any effect in the outcomes at one-year follow-up. METHODS: Multicentric, triple-blinded, randomized trial with 12-months follow-up. Subjects with isolated symptomatic reparable supraspinatus tears smaller than 3 cm and without grade 4 fatty infiltration were included. These were randomized to two groups: In the Control group an arthroscopic supraspinatus repair was performed; in the Nanofracture group the footprint was additionally prepared with nanofractures (1 mm wide, 9 mm deep microfractures). Clinical evaluation was done with Constant score, EQ-5D-3L, and Brief Pain Inventory. The primary outcome was the retear rate in MRI at 12-months follow-up. Secondary outcomes were: characteristics of the retear (at the footprint or at the musculotendinous junction) and clinical outcomes. RESULTS: Seventy-one subjects were randomized. Two were lost to follow-up, leaving 69 participants available for assessment at 12-months follow-up (33 in the Control group and 36 in the Nanofracture Group). The Nanofracture group had lower retear rates than the Control group (7/36 [19.4%] vs 14/33 [42.4%], differences significant, p = 0.038). Retear rates at the musculotendinous junction were similar but the Nanofracture group had better tendon healing rates to the bone (34/36 [94.4%] vs. 24/33 [66.71%], p = 0.014). Clinically both groups had significant improvements, but no differences were found between groups. CONCLUSION: Adding nanofractures at the footprint during an isolated supraspinatus repair lowers in half the retear rate at 12-months follow-up. This is due to improved healing at the footprint. LEVEL OF EVIDENCE: Level I.

Incidence of Acute Hamstring Injuries in Soccer: A Systematic Review of 13 Studies Involving More Than 3800 Athletes With 2 Million Sport Exposure Hours.

OBJECTIVE: To estimate the incidence and recurrence rates of acute hamstring injuries in all levels of soccer. DESIGN: Epidemiology systematic review. LITERATURE SEARCH: We searched the PubMed (including MEDLINE), CINAHL, SPORTDiscus, Embase, and Cochrane Central Register of Controlled Trials electronic databases. STUDY SELECTION CRITERIA: We included prospective studies of all levels of adult soccer players that registered acute hamstring injuries and provided a description of incidence of acute hamstring injuries per 1000 playing hours (or available data to calculate this). DATA SYNTHESIS: Due to heterogeneity, we synthesized the data descriptively. RESULTS: Thirteen studies including 3868 players met the inclusion criteria. Two of 13 included studies reported on hamstring injuries in women, and all reported the same in men. The incidence of acute hamstring injury ranged from 0.3 to 0.5 per 1000 exposure hours in women and 0.3 to 1.9 per 1000 exposure hours in men. Hamstring injuries accounted for 5% to 15% of all soccer-related injuries. Hamstring injury recurrence rates ranged from 4% to 68%, depending on the injury definition. Certainty of evidence ranged from moderate to very low. CONCLUSION: The incidence of acute hamstring injury in soccer was 0.3 to 1.9 per 1000 exposure hours. The recurrence rate was 4% to 68%. The strength of the evidence was limited by a lack of methodological rigor, the use of varying definitions for acute hamstring injury, and heterogeneous methods of reporting on acute hamstring injuries. J Orthop Sports Phys Ther 2021;51(1):27-36. Epub 11 Dec 2020. doi:10.2519/jospt.2021.9305.

Estimating time to reinjury among Washington State injured workers by degree of permanent impairment: Using state wage data to adjust for time at risk.

BACKGROUND: Many injured workers are reinjured, but reinjury risk is challenging to quantify. Because many injured workers face delayed return-to-work, or return to part-time or intermittent jobs, a calendar timescale may overestimate actual work-time at risk, yielding underestimated reinjury rates. Objectives included determining: (1) reinjury risk by degree of permanent impairment and other factors, and (2) how choice of timescale affects reinjury estimates. METHODS: This retrospective cohort study included Washington State workers' compensation (WC) claims for 43,114 injured workers, linked to state wage files (2003-2018). Three timescales were used to define at-risk denominators: (1) calendar quarters; (2) quarters with any wages; and (3) full-time equivalent (FTE) quarters, defined as cumulative work hours ÷ 520. Associations between reinjury outcomes and worker, injury, job, and WC vocational rehabilitation program participation characteristics were assessed using Cox proportional hazards regression. RESULTS: Overall reinjury rates were 5.9 per 100 worker-years using a calendar timescale (95% confidence interval [CI]: 5.8-6.0), 10.0 using any-wage quarters (95% CI: 9.9-10.2), and 12.5 using FTE quarters (95% CI: 12.3-12.7). Reinjury rates were highest in the first two quarters after initial injury, remaining elevated for about 4 years. Using FTE quarters, workers with ≥10% whole body impairment had a 34% higher risk of reinjury relative to workers with no permanent partial disability award (95% CI: 1.25-1.44); no difference was detected using calendar time. CONCLUSIONS: Timescale substantially affects reinjury estimates and comparisons between groups with differential return-to-work patterns. Linking wage data to WC claims facilitates measurement of long-term employment, yielding more accurate reinjury estimates.

Contralateral ACL tears strongly contribute to high rates of secondary ACL injuries in professional ski racers.

PURPOSE: To analyse the effects of graft selection, sex, injury complexity and time to return to competition on the odds to suffer secondary ACL injury (either re-rupture or contralateral ACL tear) in professional alpine skiers. METHODS: The database of a specialised joint surgery clinic was screened for professional alpine skiers who had participated in competitions at the FIS race, European Cup and World Cup level prior to having to undergo a primary ACL reconstruction, and who had returned to the same competitional level at least one year prior to the end of the observation period. The rates of secondary ACL injuries were statistically compared between athletes with hamstring and quadriceps tendon autografts, men and women, simple and complex (involvement of menisci or cartilage) primary ACL injuries, and between early (≤ 300 days after primary reconstruction) and late (> 300 days) returners to competition. RESULTS: Fourteen out of the 30 athletes included (46.7%) suffered secondary ACL injuries on average 29.4 ± 22.5 months after primary reconstruction. The secondary injuries comprised five re-ruptures (16.7%) and nine contralateral ACL tears (30.0%). The odds to suffer contralateral ACL tears were non-significantly higher in patients with hamstring tendon autografts (OR 5.69, n.s.) and in those whose primary injuries were classified as simple ACL tears (OR 5.31, n.s.). None of the factors assessed was associated with the odds of graft failure. CONCLUSION: The odds of ACL-injured professional alpine ski racers to suffer secondary ACL tears are nearly 50%, with subsequent contralateral ACL injuries being more common than graft failures. While statistical significance could not be established due to a lack of power, greater odds of contralateral ACL tears were observed in athletes with hamstring tendon grafts as well as those with simple primary ACL injuries. No factors potentially predisposing athletes for graft failure could be identified. LEVEL OF EVIDENCE: III.

Higher risk of contralateral anterior cruciate ligament (ACL) injury within 2 years after ACL reconstruction in under-18-year-old patients with steep tibial plateau slope.

PURPOSE: To assess the role of Tibial Plateau Slope (TPS) as risk factor for early Anterior Cruciate Ligament (ACL) reconstruction failure and contralateral ACL injury in a population of patients with less than 18 years of age and operated on with the same surgical technique. METHODS: Ninety-four consecutive patients (mean age 15.7 ± 1.5 years) with at least 2 years of follow-up, who underwent ACL reconstruction with a single-bundle plus lateral-plasty hamstring technique in the same centre were included. Subsequent ACL injuries (ipsilateral ACL revision or contralateral ACL reconstruction) were assessed within the first 2 years after surgery. Anterior, central, posterior TPS of medial compartment were measured on lateral radiographs and compared between patients with intact graft and those with a second injury. Cut-off values with sensitivity and specificity were calculated with receiver operating characteristic (ROC) analysis. Survival analysis for second ACL injuries and multivariate analysis were performed. RESULTS: Eight patients (9%) had ipsilateral ACL Revision and eight patients (9%) had contralateral ACL reconstruction. Patients with contralateral injury had a higher Central TPS with respect to those without second injury (12.6° ± 2.8° vs 9.3° ± 3.7°, p = 0.042). No differences were present in patients with ipsilateral ACL revision. Sensitivity and specificity for central TPS slope ≥ 12° to detect a contralateral rupture were 63% and 75% (p = 0.0092), for Anterior TPS were 100% and 52% (p = 0.0009). Patients with TPS values exceeding these cut-offs had higher rate of contralateral ACL injuries (19%vs4%, p = 0.0420) and lower 2-year survival (p = 0.0049). Multivariate analysis identified pre-operative sport level and TPS (either anterior or central) as risk factors for contralateral injuries. CONCLUSIONS: Steep tibial plateau slope ≥ 12° is associated with a higher risk of contralateral ACL injury within 2 years after ACL reconstruction in patients less than 18 years of age. However, TPS has no role in early ipsilateral re-injury after combined ACL reconstruction and lateral plasty. The clinical relevance is that both the surgeon and the patient should be aware of this higher risk and consider it in the rehabilitation phase to reduce the incidence of such injuries. LEVEL OF EVIDENCE: III.

Predictors of subsequent injury at work: findings from a prospective cohort of injured workers in New Zealand.

OBJECTIVES: People who have experienced a work-related injury can experience further work injuries over time. This study examines predictors of subsequent work-related injuries over 24 months among a cohort of injured workers. METHODS: Participants were those recruited to the earlier Prospective Outcomes of Injury Study (POIS) who had a work-related injury (the 'sentinel' injury). Data from POIS participant interviews were combined with administrative data from the Accident Compensation Corporation (New Zealand's no-fault universal injury insurer) and hospital discharge data. Modified Poisson regression modelling was used to examine whether presentinel injury sociodemographic and health, sentinel injury or presentinel injury work-related factors predicted subsequent work-related injuries. RESULTS: Over a third of participants (37%) had at least one subsequent work-related injury in 24 months. Factors associated with an increased risk of work-related subsequent injury included being in a job involving carrying or moving heavy loads more than half the time compared with those in jobs that never involved such tasks (RR 1.42, 95% CI 1.01 to 2.01), having an inadequate household income compared with those with an adequate household income (RR 1.33, 95% CI 1.02 1.74) and being aged 50-64 years compared with those aged 30-49 years (RR 1.25, 95% 1.00 to 1.57). CONCLUSION: Subsequent work-related injuries occur frequently, and presenting with a work-related injury indicates a potentially important intervention point for subsequent injury prevention. While the strength of associations were not strong, factors identified in this study that showed an increased risk of subsequent work-related injuries may provide a useful focus for injury prevention or rehabilitation attention.

Outcome of a neuromuscular training program on recurrent ankle sprains. Does the initial type of healthcare matter?

OBJECTIVES: To study the impact of initial healthcare for a lateral ankle sprain on the outcome of neuromuscular training (NMT) on recurrent sprains and describe athlete characteristics receiving different types of healthcare. DESIGN: Secondary analysis of three randomized trials. METHOD: From three previous trials evaluating NMT, data on athlete characteristics, type of initial healthcare and a recurrent sprain during one-year follow-up were collected (N = 705). Multilevel logistic regression analyses were used to test the impact of initial healthcare on the outcome of NMT on recurrent sprains. Potential differences in athlete characteristics between different types of healthcare were examined using one-way analysis of variance and Pearson chi-square test. RESULTS: After NMT, 39.7% of the athletes visiting paramedical care reported a recurrent sprain, 21.8% of secondary and 34.0% of primary care. Athletes who visited a physiotherapist reported more recurrent sprains, than those not visiting a physiotherapist (adjusted OR 3.15;95%CI 1.88-5.23). Athletes visiting paramedical (49.7%) and primary care (48.4%) used more braces and/or tape during sport than those not visiting any care (34.2%). CONCLUSIONS: The initial type of healthcare of athletes with an ankle sprain, that consecutively received NMT, seems to impact the occurrence of recurrent sprains. Physiotherapists may be visited by athletes with a poorer prognosis, which may be explained by different athlete characteristics.

Predictors of severe or multiple subsequent injuries over 24 months among an already-injured cohort in New Zealand.

INTRODUCTION: Interventions to reduce subsequent injuries among already-injured people presenting to healthcare providers may reduce the overall burden of injury. However, in order to develop such interventions it is necessary to understand what predicts subsequent injuries. This knowledge is currently limited for general injury populations. This prospective Subsequent Injury Study aims to determine pre-injury sociodemographic and heath factors, and injury-related factors, that predict subsequent injury claims reported to Accident Compensation Corporation (ACC, New Zealand's universal injury insurer) in the 24 months following an ACC entitlement claim injury ('sentinel' injury). Two separate outcome variables were used to identify subsequent injuries of interest: having (1) at least one high severity injury claim (New Injury Severity Scores ≥4), or (2) two or more claims (injuries of any severity). METHODS: This study combines: (1) participant interviews (from our earlier Prospective Outcomes of Injury Study), (2) ACC data about sentinel injuries which led to participants being recruited, and all subsequent injuries involving an ACC claim in the 24 months following that sentinel injury, and (3) hospital discharge data for sentinel and subsequent injuries involving hospitalisation. Potential predictors (pre-sentinel injury sociodemographic and health variables, sentinel injury related variables) were identified using modified Poisson regression models. RESULTS: Severe and multiple ACC-reported subsequent injuries (ACC-SI) were each more likely to occur for participants with a self-reported prior injury affecting them at the time of their sentinel injury, and for those who prior to their sentinel injury event had pain/discomfort, or were physically active on five or more days of the week. A lower likelihood of severe or multiple ACC-SI was more common in those aged 30-64 years compared with those aged 18-29 years, those of 'other' ethnicity compared to sole New Zealand European ethnicity, and if the sentinel injury involved hospitalisation. Multiple ACC-SI were more likely for males, and for participants with ≥2 chronic conditions compared to those with none. CONCLUSIONS: Factors identified in this study may provide useful flags to help healthcare providers and policy makers identify people at increased risk of severe or multiple subsequent injuries who may benefit from targeted injury prevention strategies or interventions.