Background: The aims of this matched cohort study were to (1) assess differences in spinopelvic characteristics between patients who sustained a dislocation after total hip arthroplasty (THA) and a control group without a dislocation, (2) identify spinopelvic characteristics associated with the risk of dislocation, and (3) propose an algorithm including individual spinopelvic characteristics to define an optimized cup orientation target to minimize dislocation risk. Methods: Fifty patients with a history of THA dislocation (29 posterior and 21 anterior dislocations) were matched for age, sex, body mass index (BMI), index diagnosis, surgical approach, and femoral head size with 200 controls. All patients underwent detailed quasi-static radiographic evaluations of the coronal (offset, center of rotation, and cup inclination/anteversion) and sagittal (pelvic tilt [PT], sacral slope [SS], pelvic incidence [PI], lumbar lordosis [LL], pelvic-femoral angle [PFA], and cup anteinclination [AI]) reconstructions. The spinopelvic balance (PI − LL), combined sagittal index (CSI = PFA + cup AI), and Hip-User Index were determined. Parameters were compared between the control and dislocation groups (2-group analysis) and between the controls and 2 dislocation groups identified according to the direction of the dislocation (3-group analysis). Important thresholds were determined from receiver operating characteristic (ROC) curve analyses and the mean values of the control group; thresholds were expanded incrementally in conjunction with running-hypothesis tests. Results: There were no coronal differences, other than cup anteversion, between groups. However, most sagittal parameters (LL, PT, CSI, PI − LL, and Hip-User Index) differed significantly. The 3 strongest predictors of instability were PI – LL >10° (sensitivity of 70% and specificity of 65% for instability regardless of direction), CSI_standing of 244° (anterior instability). A CSI that was not between 205° and 245° on the standing radiograph (CSI_standing) was associated with a significantly increased dislocation risk (odds ratio [OR]: 4.2; 95% confidence interval [CI]: 2.2 to 8.2; p < 0.001). In patients with an unbalanced and/or rigid lumbar spine, a CSI_standing that was not 215° to 235° was associated with a significantly increased dislocation risk (OR: 5.1; 95% CI: 1.8 to 14.9; p = 0.001). Conclusions: Spinopelvic imbalance (PI − LL >10°) determined from a preoperative standing lateral spinopelvic radiograph can be a useful screening tool, alerting surgeons that a patient is at increased dislocation risk. Measurement of the PFA preoperatively provides valuable information to determine the optimum cup orientation to aim for a CSI_standing of 205° to 245°, which is associated with a reduced dislocation risk. For patients at increased dislocation risk due to spinopelvic imbalance (PI − LL >10°), the range for the optimum CSI is narrower. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Thigh pain and cortical hypertrophies (CH) have been reported in the short term for specific short hip stem designs. The purpose of the study was to investigate 1) the differences in clinical outcome, thigh pain and stem survival for patients with and without CHs and 2) to identify patient and surgery-related factors being associated with the development of CHs. A consecutive series of 233 patients with 246 hips was included in the present retrospective diagnostic cohort study, who had received a total hip arthroplasty (THA) between December 2007 and 2009 with a cementless, curved, short hip stem (Fitmore, Zimmer, Warsaw, IN, USA). Clinical and radiographic follow-up, including the radiographic parameters for hip geometry reconstruction, were prospectively assessed 1, 3, and 6 to 10 years after surgery. Cortical hypertrophies were observed in 56% of the hips after a mean of 7.7 years, compared to 53% after 3.3 years being mostly located in Gruen zone 3 and 5. There was no significant difference for the Harris Hip Score and UCLA score for patients with and without CHs. Only one patient with a mild CH in Gruen zone 5 and extensive heterotopic ossifications around the neck of the stem reported thigh pain. The Kaplan Meier survival rate after 8.6 years was 99.6% (95%-CI; 97.1–99.9%) for stem revision due to aseptic loosening and no association with CHs could be detected. Postoperative increase in hip offset was the only risk factor being associated with the development of CHs in the regression model (ΔHO; OR 1.1 (1.0–1.2); p = 0.001). The percentage of cortical hypertrophies remained almost constant in the mid-term compared to the short-term with the present cementless short hip stem design. The high percentage of cortical hypertrophies seems not be a cause for concern with this specific implant in the mid-term. Diagnostic Level IV

Background: Matrix-induced autologous chondrocyte implantation (MACI), the third-generation of the technique, is an established procedure for the treatment of focal cartilage defects in the knee. However, the literature lacks long-term results of MACI with good statistical power. Purpose: To determine long-term survival and patient-reported outcomes (PROs) in a representative cohort and to identify patient- and surgery-related parameters that may influence long-term clinical outcomes. Study Design: Case series; Level of evidence, 4. Methods: A total of 103 patients were clinically evaluated at the current follow-up of 8.1 years (range, 5-11.9 years). PRO measures (PROMs) included the Knee injury and Osteoarthritis Outcome Score (KOOS), EQ-5D, visual analog scale for pain, and Tegner Activity Scale. Magnetic resonance imaging results were evaluated by using the AMADEUS (area measurement and depth and underlying structures) and MOCART (magnetic resonance observation of cartilage repair tissue) 2.0 knee score classification systems. Potential factors influencing PROs were first identified univariately and investigated in a multivariate regression model. Results: The defects had a mean size of 4.8 cm ² (range, 1.2-12 cm ² ) and were predominantly femorotibial (66%). The mean Kaplan-Meier survival rate of revision for any reason was 97.2% ± 1.6% at 10 years. In comparison to preoperative values, all PROMs were significantly improved at the current follow-up ( P < .05). The MOCART 2.0 score peaked at 12 months (mean, 80.2 ± 15.3 months) and showed no significant change at 96 months (mean, 76.1 ± 19.5 months; P = .142). The linear multivariate regression model identified an association of body mass index (BMI), MOCART 2.0 score, and number of previous knee surgeries with KOOS ( R ² = 0.41; f ² = 0.69). Further analysis of the individual determinants revealed an optimal BMI range of 20 to 29 for favorable PROs at 96 months. Significant correlations of MOCART subscores with the overall KOOS were found for graft surface and structure, bony reaction, and subchondral detectable changes. Only 30% of patients with ² previous surgeries and 20% of patients with 3 previous surgeries achieved a Patient Acceptable Symptom State (χ ² = 10.93; P = .012). Conclusion: The present study shows consistently good long-term clinical outcomes after MACI with a low revision rate and high patient satisfaction. BMI and number of previous knee surgeries may influence clinical outcomes and should be considered in patient selection and education. There is a correlation between graft structure, subchondral bone changes on magnetic resonance imaging, and long-term PROMs.

Background: There is a lack of evidence regarding the impact of time loss, match exposure, and age at injury on career progression in elite football. Therefore, the aim of this study was to identify injury characteristics and their influence on career progression in a German youth academy. Methods: During the 2012/2013 season, a prospective cohort study reported 107 time-loss injuries among 130 young athletes from an elite German soccer academy. Individual career progression was analyzed using 10-year data. Results: Injuries and time loss were not associated with career progression (p > 0.05) in the overall cohort. In the U17 and U19 groups, 24% were able to reach the professional level, with injuries significantly decreasing this probability (p = 0.002). Injuries lasting more than 28 days had a negative impact on career progression compared to minor injuries (30% vs. 10%; p = 0.02). Conclusions: Not only the characteristics of injuries, but also their impact on career development, vary with age. In the U17 and U19 age groups, serious injuries resulting in more than 28 days of absence have a negative impact on career progression. It is important to be aware of these effects in order to focus on the prevention of long-term injuries to ensure the optimal development of young athletes.

Studies that report injuries in elite youth football players are scarce. So far, no such studies have been reported in Germany. The aim of this study is to descriptively and statistically report the incidence of injuries that resulted in time-loss ≥ 4 days in the TSG Hoffenheim football academy by 138 male players aged between 12 and 19 years during one season. A total of 109 injuries were sustained by 76 players: 6.9 injuries occurred per 1000 hours of matches (95% CI, 5.0–9.6) and 0.7 injuries per 1000 hours of training (95% CI, 0.5–0.9) with a ratio of 9.8. Some 66% of all injuries occurred during matches. Injuries involved the lower limb (81%), upper limb (9%), head & neck (5%) and trunk injuries (5%). 21 (19%) of all injuries were regarded as severe and resulted in time-loss > 28 days. U16–U19 teams sustained more injuries (74, 68%) than U12–U15 (35, 32%) (P= 0.032). The most frequent diagnosis was thigh strain (22%). Time-loss ranged from 4–339 days (SD: 40, Average: 23). Many injuries were a result of strain. Available injury prevention programs should be adhered to more strictly. Dedicated epidemiological studies are needed to optimize focused injury prevention programs.