Groin injuries are common in soccer and often cause time-loss from training. While groin injuries have been linked to full effort kicking, the role of inside passing is unclear. Therefore, the purpose of this study was to investigate hip joint kinematics and muscle force, stress and contraction velocity for adductor longus and gracilis during inside passing. 3D kinematics of ten soccer players (23.4 yrs; 77.5 kg; 1.81 m) were captured with a motion capture system inside a Footbonaut. Muscle force and contraction velocity were determined with AnyBody Modelling System. Gracilis muscle forces were 9% lower compared to adductor longus (p = 0.005), but muscle stress was 183% higher in gracilis (p = 0.005). Contraction velocity reveals eccentric contraction of gracilis in the last quarter of the swing phase. Considering the combination of eccentric contraction, high muscle stress and the repetitive nature of inside passing, gracilis accumulates high loads in matches and training. These results indicate that the high incidence of groin injuries in soccer could be linked to isolated pass training. Practitioners need to be aware of the risk and refrain from sudden increases in the amount of pass training. This gives the musculoskeletal system time to adapt and might avoid career threatening injuries.

Background and purpose: Documentation of new-generation implants’ short-term performance could reassure surgeons and patients about their use, while awaiting the long-term outcome. Our aim was to compare the performance of a newer total knee arthroplasty (TKA) system with its predecessor, measured by patient-reported knee function, pain, and complication rate.Methods: We performed a multi-center, randomized, controlled trial (clinicaltrials.gov ID: NCT03073941). 314 patients with primary osteoarthritis were randomized to treatment with a Persona or NexGen cruciate-retaining TKA system and followed for 2 years. The primary outcome was measured with the patient-reported outcome (PRO) Oxford Knee Score (OKS) 2 years post-surgery. Secondary outcomes were the OKS-Activity and Participation questionnaire (OKS-APQ), Forgotten Joint Score (FJS), EQ-5D-3L, and number of complications during the study period. Responder analyses were performed using Patient Acceptable Symptom State (PASS) and Minimal Important Change (MIC) criteria.Results: Primary outcome was available from 289 patients (92%). We found no difference in adjusted mean OKS between the groups 2 years post-surgery (0.1, 95% confidence interval –1.4 to 1.7). We found no significant differences in adjusted mean of secondary PROs, PRO time-weighted averages, proportion of patients with PASS or MIC, or complications 2 years post-surgery.Conclusion: We found no difference in OKS 2 years post-surgery, or in any secondary variables analyzed including complications, between the 2 TKA systems. Short-term safety and performance of the Persona TKA was comparable to its predecessor

Background: Cups are more frequently revised than stems after uncemented total hip arthroplasty, which warrants the development of cup surfaces that provide long-lasting, stable fixation. Large heads have become popular with the aim of reducing dislocation rates, but they generate greater frictional torque that may compromise cup fixation. We aimed to investigate (1) if a novel porous titanium surface provides superior cup fixation when compared with a porous plasma spray (PPS) surface and (2) if the use of the largest possible head compromises cup fixation when compared with a 32-mm head. Methods: Ninety-six patients were randomized to receive either a cup with a porous titanium coating (PTC) or a cup with PPS. A second randomization was performed to either the largest possible (36 to 44-mm) or a 32-mm head in metal-on-vitamin-E-infused polyethylene bearings. Roentgen stereophotogrammetric analysis (RSA) examinations were obtained postoperatively at 3, 12, and 24 months. The primary outcome was proximal cup migration when comparing the 2 cup surfaces and also when comparing the largest possible head with the 32-mm head. The patients were followed for 2 years. Results: The median (and interquartile range) proximal cup migration was 0.15 mm (0.02 to 0.32 mm) for the PTC cup and 0.21 mm (0.11 to 0.34 mm) for the PPS cup. The largest possible head had a proximal cup migration of 0.15 mm (0.09 to 0.31 mm), and the 32-mm head had a proximal cup migration of 0.20 mm (0.04 to 0.35 mm). There were no significant differences between the cup surface (p = 0.378) or the head size (p = 0.693) groups. Conclusions: Early cup fixation was not superior with the novel PTC cup; the use of the largest possible head (36 to 44 mm) did not compromise early cup fixation. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Medially congruent (MC) bearings aim at promoting medial pivoting after total knee arthroplasty (TKA), as the congruency provides further constraint for the medial femoral compartment. However, this design difference could alter intra-articular force distribution, potentially compromising fixation of the tibia implant. The aim of this study was to compare migration, measured with radiostereometric analysis (RSA), of an MC to a more traditional cruciate retaining (CR) TKA system. Secondary aims were to compare patient-perceived treatment outcome and number of complications between the treatment groups. Sixty patients undergoing TKA were randomized to an MC or CR bearing and had follow up visits after 3 months, 1 and 2 years. Primary outcome was tibia implant migration, measured by maximal total point motion (MTPM) with model-based RSA, 2 years post-surgery. Secondary outcomes were tibia MTPM, change in patient-reported outcome measurements (PROMs) and number of complications registered at all follow up visits. Primary outcome was available for 52 patients (27 MC patients, 25 CR patients). We found no difference in tibia MTPM between the MC and CR groups 2 years post-surgery. Median (interquartile range) MTPM was 0.60 (0.39-0.97) mm and 0.48 (0.32-0.78) mm in the MC and CR group, respectively (P = 0.167). There were no between-group differences in improvement in PROMs and no between-group differences in number of complications. We found no compromising of tibia implant fixation in TKA by choosing an MC bearing, when compared with a CR bearing. PROMs and complication rates suggest comparable treatment results with both types of bearings in TKA.

Introduction: This study identified the incidence and potential risk factors of tibial component subsidence in cementless unicompartmental knee arthroplasty (UKA) and evaluated its clinical impact. Methods: This retrospective cohort study analyzed 123 knees that underwent cementless Oxford mobile-bearing UKA. Anteroposterior and lateral radiographs were obtained preoperatively, immediately postoperatively, and at the first outpatient follow-up (3–6 months). Valgus subsidence was defined as a valgus change of > 2° in the tibial component angle between the immediate postoperative and first follow-up radiographs. The patients were categorized according to the presence or absence of subsidence. The alignment, component angles, and femoral component position relative to the tibial component in the coronal plane were compared between groups. Clinical outcomes were assessed using the Oxford Knee Score (OKS) at 3 months, 1 year, and 2 years. Results: Tibial component subsidence incidence was 4.8%. The immediate postoperative tibial component alignment was significantly less varus in the subsidence group than in the non-subsidence group (1.0 ± 1.9° vs. 3.3 ± 2.2°, p = 0.019). The femoral component was positioned significantly more laterally than the tibial component in the subsidence group ( p = 0.009). The non-subsidence group was older and had a greater postoperative posterior tibial slope than the subsidence group; however, these differences were not statistically significant ( p = 0.069 and 0.052, respectively). Clinical outcomes assessed by OKS were not significantly different between groups at any time point. No revision surgery owing to subsidence was required within 2 years. Conclusions: Subsidence occurred in 4.8% of cases and was associated with a relative lateral placement of the femoral component and less varus of tibial component alignment. A tibial cut with an appropriate varus angle may be protective. Given the small number of events, these findings should be interpreted as exploratory and inform future prospective studies.

Background/Objectives: Spasticity in children with cerebral palsy (CP) can impair motor-related functions. The objective of this exploratory, prospective study was to examine if transcutaneous electrical nerve stimulation (TENS) in a whole-body suit leads to changes in spasticity and other related effects. Methods: Thirty-one children with CP GMFCS III–V, with a median age of 11.0 years (age range of 7–17 years), were consecutively included, and they used the suit with TENS for 24 weeks. The primary outcome was spasticity measured using the Modified Ashworth Scale (MAS). Functional motor-related tasks were evaluated by the Goal Attainment Scale (SMART GAS). The Modified Tardieu Scale (MTS), passive Range of Motion (pROM), GMFM-66, and Posture and Postural Ability Scale (PPAS) assessments were performed. Results: Seventeen subjects (17/31) completed the 24 weeks. Dropout was due to difficulty in donning the suit. The level of overall spasticity, most pronounced in the proximal arms and legs, was reduced according to the MAS, but not the MTS or pROM. Subject-relevant motor-related goals improved significantly in standing/walking and hand/arm function. Changes in the GMFM-66 and PPAS were not significant. Conclusions: Although there were statistically significant but underpowered changes in the MAS after 24 weeks, there were no clinically relevant effects. Exploratorily, we found observer-reliant motor-related functional improvements, which, however, we were unable to detect when trying to quantify them. Donning the suit led to dropout throughout the study. Caregivers need to allocate time, mental capacity and have the physical skill set for donning the suit for long-term use.