KNEE JOINT LOADING OF SCISSOR-KICK JUMP LANDINGS: A COMPARISON BETWEEN ELITE AND RECREATIONAL BADMINTON PLAYERS

Badminton players at all levels perform a variety of badminton specific jump-stroke movements during training and match play, which expose their knees to high loads during the subsequent landing phase. Therefore, the purpose of this study was to compare the knee joint kinematics and kinetics of elite and recreational male badminton players during scissor-kick jump landings. Ten Danish national male badminton players and 10 recreational male badminton players completed a series of simulated scissor-kick jumps in a biomechanical laboratory. Three-dimensional knee joint angles and external joint moments were recorded for the non-racket leg during the landing phase. One-dimensional statistical parametric mapping was used to statistically compare the landing kinematics and kinetics of the knee for elite and recreational players. The landing phase was highly similar between groups and associated with high external knee abduction moments, particularly for the recreational players, which resemble those previously reported in sports specific single-leg landing situations with high ACL injury risk. The only significant difference observed between elite and recreational players were found in the push-off phase, where elite players generate more power from the muscles around the knee joint, through greater external adduction and inwards rotations moments, allowing them to accelerate significantly faster forward upon landing compared to recreational players. The high knee loads players experience during scissor-kick landings may contribute to the high incidence of knee injuries observed in both elite and recreational badminton

Which factors differentiate athletes with hip/groin pain from those without? A systematic review with meta-analysis

Background: Hip and groin injuries are common in many sports. Understanding the factors differentiating athletes with hip/groin pain from those without these injuries could facilitate management and prevention. Objective: Conduct a systematic review and meta-analysis of the literature on factors differentiating athletes with and without hip/groin pain. Methods: The review was registered as PROSPERO CRD42014007416 and a comprehensive, systematic search was conducted in June 2014. Inclusion criteria were: cross-sectional, cohort or case-control study designs of n>10 that examined outcome measures differentiating athletes with and without hip/groin pain. Two authors independently screened search results, assessed study quality, and performed data extraction. Methodological heterogeneity was determined and data pooled for meta-analysis when appropriate. A best evidence synthesis was performed on the remaining outcome measures. Results: Of 2251 titles identified, 17 articles were included of which 10 were high quality. Sixty two different outcome measures were examined, 8 underwent meta-analysis. Pooled data showed strong evidence that athletes with hip/groin pain demonstrated: pain and lower strength on the adductor squeeze test, reduced range of motion in hip internal rotation and bent knee fall out; however, hip external rotation range was equivalent to controls. Strong evidence was found that lower patient-reported outcome (PRO) scores, altered trunk muscle function, and moderate evidence of bone oedema and secondary cleft sign were associated with hip/groin pain. Conclusions: PROs, pain and reduced strength on the adductor squeeze test, reduced range of motion in internal rotation and bent knee fall out are the outcome measures that best differentiate athletes with hip/groin pain from those without this pain

Patient-reported outcome and muscle-tendon pain after periacetabular osteotomy are related:1-year follow-up in 82 patients with hip dysplasia

Background and purpose — Larger prospective studies investigating periacetabular osteotomy (PAO) with patient-reported outcome measures developed for young patients are lacking. We investigated changes in patient-reported outcome (PRO), changes in muscle–tendon pain, and any associations between them from before to 1 year after PAO. Patients and methods — Outcome after PAO was investigated in 82 patients. PRO was investigated with the Copenhagen Hip and Groin Outcome Score (HAGOS). Muscle–tendon pain in the hip and groin region was identified with standardized clinical tests, and any associations between them were analyzed with multivariable linear regressions. Results — HAGOS subscales improved statistically significantly from before to 1 year after PAO with effect sizes ranging from medium to very large (0.66–1.37). Muscle–tendon pain in the hip and groin region showed a large decrease in prevalence from 74% (95% CI 64–83) before PAO to 35% (95% CI 25–47) 1 year after PAO. Statistically significant associations were observed between changes in HAGOS and change in the sum of muscle–tendon pain, ranging from –4.7 (95% CI –8.4 to –1.0) to –8.2 (95% CI –13 to –3.3) HAGOS points per extra painful entity across all subscales from before to 1 year after PAO. Interpretation — Patients with hip dysplasia experience medium to very large improvements in PRO 1 year after PAO, associated with decreased muscle–tendon pain. The understanding of hip dysplasia as solely a joint disease should be reconsidered since muscle–tendon pain seems to play an important role in relation to the outcome after PAO. Trial registration: ClinicalTrials.gov identifier: 20140401PAO

Association of Skeletal Maturity and Injury Risk in Elite Youth Soccer Players:A 4-Season Prospective Study With Survival Analysis

Background: The association between injury risk and skeletal maturity in youth soccer has received little attention. Purpose: To prospectively investigate injury patterns and incidence in relation to skeletal maturity in elite youth academy soccer players and to determine the injury risks associated with the skeletal maturity status, both overall and to the lower limb apophysis. Study Design: Descriptive epidemiology study. Methods: All injuries that required medical attention and led to time loss were recorded prospectively during 4 consecutive seasons in 283 unique soccer players from U-13 (12 years of age) to U-19 (18 years). The skeletal age (SA) was assessed in 454 player-seasons using the Fels method, and skeletal maturity status (SA minus chronological age) was classified as follows: late, SA >1 year behind chronological age; normal, SA ±1 year of chronological age; early, SA >1 year ahead of chronological age; and mature, SA = 18 years. An adjusted Cox regression model was used to analyze the injury risk. Results: A total of 1565 injuries were recorded; 60% were time-loss injuries, resulting in 17,772 days lost. Adjusted injury-free survival analysis showed a significantly greater hazard ratio (HR) for different status of skeletal maturity: early vs normal (HR = 1.26 [95% CI, 1.11-1.42]; P < .001) and early vs mature (HR = 1.35 [95% CI, 1.17-1.56]; P < .001). Players who were skeletally mature at the wrist had a substantially decreased risk of lower extremity apophyseal injuries (by 45%-61%) compared with late (P < .05), normal (P < .05), and early (P < .001) maturers. Conclusion: Musculoskeletal injury patterns and injury risks varied depending on the players’ skeletal maturity status. Early maturers had the greatest overall adjusted injury risk. Players who were already skeletally mature at the wrist had the lowest risk of lower extremity apophyseal injuries but were still vulnerable for hip and pelvis apophyseal injuries

Effectiveness of Adding a Large Dose of Shoulder Strengthening to Current Nonoperative Care for Subacromial Impingement:A Pragmatic, Double-Blind Randomized Controlled Trial (SExSI Trial)

BACKGROUND: A strong recommendation against subacromial decompression surgery was issued in 2019. This leaves nonoperative care as the only treatment option, but recent studies suggest that the dose of strengthening exercise is not sufficient in current nonoperative care. At this point, it is unknown if adding more strengthening to current nonoperative care is of clinical value. PURPOSE: To assess the effectiveness of adding a large dose of shoulder strengthening to current nonoperative care for subacromial impingement compared with usual care alone. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: In this double-blinded, pragmatic randomized controlled trial, we randomly allocated 200 consecutive patients referred to orthopaedic shoulder specialist care for long-standing shoulder pain (>3 months), aged 18 to 65 years and diagnosed with subacromial impingement using validated criteria, to the intervention group (IG) or control group (CG). Outcome assessors were blinded, and participants were blinded to the study hypothesis as well as to the treatment method in the other group. The CG received usual nonoperative care; the IG underwent the same plus an add-on intervention designed to at least double the total dose of shoulder strengthening. The primary outcome was the Shoulder Pain and Disability Index (SPADI; 0-100) at 4-month follow-up, with 10 points defined as the minimal clinically important difference. Secondary outcomes included shoulder strength, range of motion, health-related quality of life, and the Patient Acceptable Symptom State (PASS). RESULTS: Intention-to-treat and per-protocol analyses showed no significant or clinically relevant between-group differences for any outcome. From baseline to 4-month follow-up, SPADI scores improved in both groups (intention-to-treat analysis; IG, –22.1 points; CG, –22.7 points; between-group mean difference, 0.6 points [95% CI, –5.5 to 6.6]). At 4 months after randomization, only 54% of the IG and 48% of the CG (P = .4127) reached the PASS. No serious adverse events were reported. CONCLUSION: Adding a large dose of shoulder strengthening to current nonoperative care for patients with subacromial impingement did not result in superior shoulder-specific patient-reported outcomes. Moreover, approximately half of all randomized patients did not achieve the PASS after 4 months of nonoperative care, leaving many of these patients with unacceptable symptoms. This study showed that adding more exercise is not a viable solution to this problem. REGISTRATION: NCT02747251 (ClinicalTrials.gov identifier

Injury incidence and burden in a youth elite football academy: A four-season prospective studyof 551 players aged from under 9 to under 19 years

Objective Investigate the incidence and burden of injuries by age group in youth football (soccer) academy players during four consecutive seasons. Methods All injuries that caused time-loss or required medical attention (as per consensus definitions) were prospectively recorded in 551 youth football players from under 9 years to under 19 years. Injury incidence (II) and burden (IB) were calculated as number of injuries per squad season (s-s), as well as for type, location and age groups. Results A total of 2204 injuries were recorded. 40% (n=882) required medical attention and 60% (n=1322) caused time-loss. The total time-loss was 25 034 days. A squad of 25 players sustained an average of 30 time-loss injuries (TLI) per s-s with an IB of 574 days lost per s-s. Compared with the other age groups, U-16 players had the highest TLI incidence per s-s (95% CI lower-upper): II= 59 (52 to 67); IB=992 days; (963 to 1022) and U-18 players had the greatest burden per s-s: II= 42.1 (36.1 to 49.1); IB= 1408 days (1373 to 1444). Across the cohort of players, contusions (II=7.7/s-s), sprains (II=4.9/s-s) and growth-related injuries (II=4.3/s-s) were the most common TLI. Meniscus/cartilage injuries had the greatest injury severity (95% CI lower-upper): II= 0.4 (0.3 to 0.7), IB= 73 days (22 to 181). The burden (95% CI lower-upper) of physeal fractures (II= 0.8; 0.6 to 1.2; IB= 58 days; 33 to 78) was double than non-physeal fractures. Summary At this youth football academy, each squad of 25 players averaged 30 injuries per season which resulted in 574 days lost. The highest incidence of TLI occurred in under-16 players, while the highest IB occurred in under-18 players