Reconstruction of proximal hamstring ruptures restores joint biomechanics during various walking conditions.

PURPOSE: We aimed to examine the functional outcome in different walking conditions in elderly adults who underwent surgical repair after a non-contact hamstring injury. Our objective was to compare lower limb kinematics and kinetics over the entire gait cycle between the injured and contralateral leg in overground and level and uphill treadmill walking. METHODS: 12 patients (mean ± SD, age: 65 ± 9 years; body mass index: 30 ± 6 kg/m2) walked at self-selected speed in overground (0% slope) and treadmill conditions (0% and 10% slope). We measured spatiotemporal parameters, joint angles (normalised to gait cycle) and joint moments (normalised to stance phase) of the hip, knee and ankle. Data between sides were compared using paired sample t-tests (p < 0.05) and continuous 95% confidence intervals of the paired difference between trajectories. RESULTS: Patients walked at an average speed of 1.31 ± 0.26 m/second overground and 0.92 ± 0.31 m/second on the treadmill. Spatiotemporal parameters were comparable between the injured and contralateral leg (p > 0.05). Joint kinematic and joint kinetic trajectories were comparable between sides for all walking conditions. CONCLUSIONS: Refixation of the proximal hamstring tendons resulted in comparable ambulatory mechanics at least 1 year after surgery in the injured leg and the contralateral leg, which were all within the range of normative values reported in the literature. These results complement our previous findings on hamstring repair in terms of clinical outcomes and muscle strength and support that surgical repair achieves good functional outcomes in terms of ambulation in an elderly population. TRIAL REGISTRATION: clinicaltrials.gov (NCT04867746).

Gamification of Physical Therapy Exercises Using Commercial Entertainment Content: A Safety and Feasibility Study.

Independent physiotherapy at home is a crucial element of rehabilitative care for a wide range of conditions as it constitutes a large portion of the overall therapy dose. However, up to 80% of individuals who are prescribed at-home physiotherapy do not consistently adhere to their treatment schedule, resulting in poor treatment outcomes. This is likely due to a lack of motivation and progress tracking in the current standard of care. We have developed a novel software prototype that allows users to control commercial entertainment content, such as video games or interactive music videos, with their movements during physiotherapy. By connecting therapy to proven entertainment content, we aim to improve on the current motivational deficits. This study investigated the safety and feasibility of this concept in a controlled environment over four physical therapy sessions with seven patients suffering from musculoskeletal and neurological conditions. As a secondary outcome, patients were asked about their enjoyment, perceived competence and effort using the Intrinsic Motivation Inventory (IMI) questionnaire. All participants were able to interact with the presented entertainment content and completed the study with no adverse events. Despite the diversity in pathology, age and training scenarios, the entertainment content maintained the patients' enjoyment with a high average rate of 6/7 on the IMI scale. Interacting with commercial entertainment content by doing physical therapy exercises was feasible, safe, and well-received over the six-week study period.

Use of Short Stems in Revision Total Hip Arthroplasty: A Retrospective Observational Study of 31 Patients.

Background and Objectives: Implantation of a short femoral stem in revision total hip arthroplasty (rTHA) could reduce the perioperative time, soft tissue damage, and preserve the bone stock of the proximal femur. The objective of this study was to describe the clinical and radiographic outcomes after the use of short stems in rTHA with a follow-up of 1 to 5 years. Materials and Methods: This retrospective, single center, and observational study analyzed the data of 31 patients (12 female, 19 male) with a median (interquartile range) age of 68.2 years (61.2-78.4) and BMI of 26.7 kg/m2 (24.6-29.4) who received an uncemented short femoral stem in rTHA between 2015 and 2020. Clinical outcomes were extracted from medical reports and assessed using the modified Harris Hip Score (mHHS), the numerical rating scale (NRS) for pain and satisfaction, and the UCLA Physical Activity Score. Radiographs were analyzed for stem subsidence, fixation, and bone parameters. The Wilcoxon test was used for pre-post rTHA differences (p < 0.05); clinical relevance was interpreted based on effect sizes according to Cohen's d. Results: All the clinical outcome measures improved significantly (p ≤ 0.001) at follow-up compared to preoperative status, with large effect sizes (Cohen's d) ranging from 2.8 to 1.7. At the last follow-up, the median (interquartile) mHHS was 80.9 (58.6-93.5). Stem fixation was stable in all cases. Complications included stem subsidence of 3 mm (n = 1) and 10 mm (n = 1), heterotopic ossification Brooker stage III (n = 2), intraoperative femur perforation (n = 1), periprosthetic fracture Vancouver type A (n = 1), and dislocation (n = 2). Conclusions: The good clinical results in our selective study population of patients with mild to moderate bone deficiency, supported by large effect sizes, together with a complication rate within the normal range, support the consideration of short stems as a surgical option after a thorough preoperative analysis.

Early ACL reconstruction shows an improved recovery of isokinetic thigh muscle strength compared to delayed or chronic cases.

INTRODUCTION: The recovery of periarticular strength is a major criterion in return-to-play testing. The rationale of the study was to assess the impact of the delay of surgery (∆ between injury and surgery) on knee extensor and knee flexor strength of anterior cruciate ligament (ACL)-deficient patients six months after reconstruction. MATERIALS AND METHODS: In a retrospective cohort study, all patients with ACL ruptures between 03/2015 and 12/2019 were analyzed. Inclusion criteria were isolated ACL rupture without any associated lesions undergoing a reconstruction using ipsilateral hamstring tendon autograft and adherence to isokinetic strength testing before and at 5-7 months postoperatively. These patients were then clustered into three groups: EARLY reconstruction (∆ < 42 days), DELAYED reconstruction (∆42-180d), and CHRONIC (∆ > 180d). Knee extensor and flexor strength of the ipsi- and contralateral leg were analyzed by concentric isokinetic measurement (60°/s). Primary outcomes were the maximal knee extension and flexion torque, hamstrings-to-quadriceps ratio (H/Q) ratio), and the corresponding limb symmetry indices. RESULTS: n = 444 patients met the inclusion criteria. From EARLY to DELAYED to CHRONIC, a progressive reduction in postoperative strength performance was observed in knee extension (1.65 ± 0.45 to 1.62 ± 0.52 to 1.51 ± 0.5 Nm/kg resp.) and flexion (1.22 ± 0.29 to 1.18 ± 0.3 to 1.13 ± 0.31 Nm/kg resp.) strength on the ACL reconstructed leg. This general loss in periarticular strength was already apparent in the preoperative performance even on the healthy side. When controlling for the preoperative performance using ANCOVA analysis, EARLY performed significantly better than DELAYED (extension p = 0.001, flexion p = .02) and CHRONIC (extension p = 0.005, flexion p < 0.001). Also, there were significantly higher values for H/Q ratio in the injured leg across all groups where the H/Q ratio increased from EARLY to CHRONIC and from pre- to postoperative values. CONCLUSIONS: With respect to the force generating capacity when returning-to-play, it is advantageous to seek for an early ACL reconstruction within the first 12 weeks after the injury. The increasing loss of thigh muscle strength observed in delayed or chronic cases affects the injured and also the non-injured leg. LEVEL OF EVIDENCE: III, retrospective cohort study.

Development and validation of a clinical prediction model for return to work after arthroscopic anterior crucial ligament reconstruction.

BACKGROUND: Occupational reintegration after anterior cruciate ligament (ACL) rupture is an important clinical issue including economic and health-related perspectives. This study aims to develop and validate a clinical prediction model of return to work in patients with ACL reconstruction surgery considering evidence-based clinical, anthropometric and occupational factors. METHODS: Data of 562 patients with an ACL rupture receiving an arthroscopic ACL reconstruction were used for analysis. A model for the binary outcome of experiencing an inability to work period of less or more than 14 days (model 1), and a model for finding predictor variables that are linearly associated with a continuous longer inability to work period of over 14 days (model 2) was calculated. Pre-operative determinants including patient characteristics and peri-operative factors were used as predictors for both models. RESULTS: For model 1, the highest increase in odds was observed for the occupational type of work, followed by injury of the medial collateral ligament together with partial weight bearing. Small protective effects were observed for female sex, meniscal suture and work with light occupational strain. The type of occupational work, together with revision surgery, a longer duration of limited range of motion and the presence of cartilage therapy were risk factors for longer inability to work. Discrimination and calibration statistics were satisfactory in internal validation. CONCLUSION: Within the framework of clinical consideration, these prediction models will serve as an estimator for patients, their treating physicians and the socioeconomic partners to forecast the individual cost and benefit of ACL injury.

Pre-operative knee extensor and flexor torque after secondary ACL rupture: a comparative retrospective analysis.

BACKGROUND: Secondary anterior cruciate ligament (ACL) ruptures are a relevant clinical concern after surgical treatment of a primary ACL rupture. However, there is a lack of scientific evidence related to the role of muscle strength prior to revision surgery in a second ACL rupture. The aim of this study was to assess differences in knee extensor and flexor strength in patients before primary and secondary ACL reconstruction compared to healthy controls. METHODS: In total, n = 69 age, weight and sex matched individuals were included in the study: n = 23 patients with isolated primary ACL rupture, n = 23 with secondary ACL rupture, and n = 23 matched healthy controls. Maximal isokinetic knee extension and flexion torque normalized to body mass was assessed for both legs. RESULTS: For patients with secondary ACL ruptures, torques were reduced in the non-injured (extension: 1.94 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.25 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.70 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.14 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. For patients with a primary ACL rupture torques were reduced in the non-injured (extension: 1.92 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.24 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.38 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.01 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. There were no differences between patients with primary and secondary ruptures, except of the knee extension on the injured leg showing higher values after a secondary ACL rupture (1.38 Nm/kg vs. 1.70 Nm/kg, p < 0.05). CONCLUSIONS: The findings indicate that maximal knee torques were significantly reduced in patients with primary and secondary ACL ruptures before surgical reconstruction for the non-injured and injured leg as compared to healthy controls. Further investigations are needed to assess strength abilities before and after a second revision within a prospective design.

Modified defense reaction reduces biomechanical and myoelectrical ACL injury risk factors in elite Judo.

In judo, an anterior cruciate ligament (ACL) injury is the most severe injury an athlete could experience. Most ACL ruptures occur when defending against an osoto-gari attack. This study aims to identify ACL risk factors during osoto-gari defence and implement a modified osoto-gari defence reaction, which is assumed to improve myoelectric patterns and ameliorate critical biomechanical risk factors for ACL injuries. Twenty-six elite judokas were enrolled in the cross-over trial (female: 6; male: 20). 3D kinematics and force dynamometrics were combined with electromyographical recordings to assess the effects of the common and the modified osoto-gari defence reaction. Compared to the common osoto-gari defence reaction (maximal knee flexion: 29 ± 12°; maximal valgus: 10 ± 5°; maximal valgus moment: 58 ± 17 Nm; peak internal rotation: 9 ± 5°), the modified osoto-gari defence reaction showed significantly reduced knee angles (31 ± 10° p < 0.05; 1 ± 0° p < 0.05; 31 ± 9 Nm p < 0.05; 3 ± 0° p < 0.05). The myoelectric activity of the hamstring increased (+5±% to +27±%, p < 0.05) in the modified compared to common defence reaction. The modified osoto-gari defence reaction reduced critical biomechanical risk factors and increased hamstring myoelectric activity. We recommend the implementation of the modified osoto-gari defence reaction in judo practice and seek to evaluate its long-term effectiveness in decreasing ACL injury incidences in elite judo.

Midterm functional performance following open surgical repair of acute Achilles tendon rupture.

INTRODUCTION: Various impairments such as soleus atrophy and consecutive functional deficits in end-range plantarflexion have been described in surgical repair of acute Achilles tendon rupture. The aim of this study was to assess the functional performance at midterm following open surgical repair. MATERIALS AND METHODS: This cross-sectional study includes n = 52 patients which were tested on average 3.5 ± 1.4 years postoperatively using three different functional performance tests and patient-reported outcome measures. Two different surgical techniques (anatomical repair = AR vs. conventional repair = CR) were compared in a subanalysis. The testing included isokinetic strength testing, a novel setup of heel-rise testing using a marker-based 3D motion analysis system and a gait analysis. RESULTS: At an average 3.5 years post-surgery, there is a persisting deficit in plantarflexion strength of 10.2%. Moreover, analysis of maximum peak torque angle and strength deficits according to the plantarflexion angle revealed that these deficits are not equally distributed across the range of motion. AR results in a significantly smaller deficit at 10° of plantarflexion compared to CR (13.9 vs. 29.9%, p < 0.05). This reflects into the functional performance during different modalities (static vs. dynamic) in this novel method of heel-rise testing. CONCLUSION: In summary, there are persisting functional deficits at > 3 years following Achilles tendon repair which range from strength deficits to specific impairments of functional performance e.g. during heel rise. Anatomical reconstruction is associated with an improved functional performance potentially due to a more symmetric strength during end-range plantarflexion which transfers into a higher satisfaction during athletic activities. LEVEL OF EVIDENCE: III, retrospective cohort study.

Neuromechanical activation of triceps surae muscle remains altered at 3.5 years following open surgical repair of acute Achilles tendon rupture.

PURPOSE: To assess whether the neuromuscular activation pattern following Achilles tendon rupture and repair may contributes to the observable functional deficits in this severe and increasingly frequent injury. METHODS: In this study, the neuromuscular activation using surface EMG of n = 52 patients was assessed during a battery of functional performance tasks to assess potential alterations of muscular activation and recruitment. We analyzed the injured leg vs. the contralateral healthy leg at a mean of 3.5 years following open surgical repair. The testing battery included isokinetic strength testing, bipedal and single-legged heel-rise testing as well as gait analysis. RESULTS: During isokinetic testing, we observed a higher activation integral for all triceps surae muscles of the injured side during active dorsiflexion, e.g., eccentric loading on the injured leg, while concentric plantarflexion showed no significant difference. Dynamic heel-rise testing showed a higher activation in concentric and eccentric loading for all posterior muscles on the injured side (not significant); while static heel-rise for 10 sec. revealed a significantly higher activation. Further analysis of frequency of fast Fourier-transformed EMG revealed a significantly higher median frequency in the injured leg. Gait analysis revealed a higher pre-activation of the tibialis anterior before ground contact, while medial and lateral gastrocnemius muscles of the injured leg showed a significantly higher activation during push-off phase. CONCLUSIONS: The results of this study provide evidence on the neuromuscular changes 3.5 years following open surgical Achilles tendon repair. These complex neuromuscular changes are manifested to produce the maximum force output whilst protecting the previously injured tendon. The observed alterations may be related to an increased recruitment of type II muscle fibers which could make the muscles prone to fatigue. LEVEL OF EVIDENCE: III.

Functional deficits in chronic mechanical ankle instability.

BACKGROUND: The interaction of functional and mechanical deficits in chronic ankle instability remains a major issue in current research. After an index sprain, some patients develop sufficient coping strategies, while others require mechanical support. This study aimed to analyze persisting functional deficits in mechanically unstable ankles requiring operative stabilization. METHODS: We retrospectively analyzed the functional testing of 43 patients suffering from chronic, unilateral mechanical ankle instability (MAI) and in which long-term conservative treatment had failed. Manual testing and arthroscopy confirmed mechanical instability. The functional testing included balance test, gait analysis, and concentric-concentric, isokinetic strength measurements and was compared between the non-affected and the MAI ankles. RESULTS: Plantarflexion, supination, and pronation strength was significantly reduced in MAI ankles. A sub-analysis of the strength measurement revealed that in non-MAI ankles, the peak pronation torque was reached earlier during pronation (maximum peak torque angle at 20° vs. 14° of supination, p < 0.001). Furthermore, active range of motion was reduced in dorsiflexion and supination. In balance testing, patients exhibited a significant increased perimeter for the injured ankle (p < 0.02). During gait analysis, we observed an increased external rotation in MAI (8.7 vs. 6.8°, p<0.02). CONCLUSIONS: This study assesses functional deficits existent in a well-defined population of patients suffering from chronic MAI. Impairments of postural sway, gait asymmetries, and asymmetric isokinetic strength can be observed despite long-term functional treatment. The finding that pronation strength is particularly reduced with the foot in a close-to-accident position indicates potential muscular dysfunction in MAI. Possibly, these deficits alongside the underlying mechanical instability characterize patients requiring mechanical stabilization.

[Biomechanical Evaluation of Rehabilitation after Surgical Repair of Achilles Tendon Ruptures]. / Biomechanische Evaluation des Rehabilitationsverlaufs nach operativer Versorgung der Achillessehnenruptur.

Background Muscles and tendons are subjected to a high level of stress in everyday life and sports. This often leads to injuries and is associated with training failure and reduced performance as well as with high costs for treatment and rehabilitation. Fast and successful treatment is therefore very important, both from an athletic and economic point of view. This study aims to demonstrate the relevance of biomechanical procedures for the objective monitoring of rehabilitation. At the same time, the results are to be used to establish progress and evaluation criteria for an efficient and controlled rehabilitation. Patients and methods In a retrospective study, a total of 42 patients were evaluated biomechanically after surgical repair of a complete Achilles tendon rupture 18 (18 W) and 26 weeks (26 W) postoperatively. Ground reaction forces in barefoot walking on a treadmill as well as isokinetic maximum strength for the plantar flexors and dorsal extensors were assessed. Results The push-off force on the injured side increased from 0.88 (18 W) to 0.95 (26 W). The percentage of heel contact time on the injured side was 59 % at 18 W and 55 % at 26 W. Plantar flexion torque increased from 70 Nm (18 W) to 90 Nm (26 W) on average on the injured side. The percentage of the plantar flexion deficit (injured/non-injured side) decreased from 34 % to 21 % on the two postoperative measuring dates. Conclusions The described biomechanical methods allow for a quantitative assessment and an objective control of the rehabilitation process. The results can also be used for the definition of evaluation and progression criteria in order to assess the progress of a patient's therapy and to guide the rehabilitation process in a controlled manner.

Do the feet of German and Australian children differ in structure? Implications for children's shoe design.

The purpose of this study was to determine whether there were any significant differences in the morphology of the feet of children living on two different continents. The shape and dimensions of the feet of 86 preschool and 419 primary school children from Australia, matched to the same number of German children for age, gender, height and BMI, were compared. The German children display significantly longer and flatter feet relative to their Australian counterparts, whereas the Australian children reveal a significantly smaller ball angle, implying that the forefoot of the Australian children is squarer in shape. These findings imply that footwear must be designed to cater to the unique foot dimensions of children in different continents to ensure that shoe shape matches foot shape. Most footwear companies do not vary the dimensions of their shoe lasts to accommodate intercontinental differences in foot morphology based on racial and/or environmental factors. The results of this study will have immediate implications for the design of comfortable footwear suitable for the developing feet of children.

Reproducibility of plantar pressure distribution data in barefoot running.

The aim of this study was to provide detailed information on rationales, calculations, and results of common methods used to quantify reproducibility in plantar pressure variables. Recreational runners (N=95) performed multiple barefoot running trials in a laboratory setup, and pressure variables were analyzed in nine distinct subareas of the foot. Reproducibility was assessed by calculating intraclass correlation coefficients (ICC) and the root mean square error (RMSE). Intraclass correlation coefficients ranged from 0.58 to 0.99, depending on the respective variable and type of ICC. Root mean square errors ranged between 2.3 and 3.1% for relative force-time integrals, between 0.07 and 0.23 for maximum force (Fmax), and between 107 and 278 kPa for maximum pressure (Pmax), depending on the subarea of the foot. Force-time integral variables demonstrated the best within-subject reproducibility. Rear-foot data suffered from slightly increased measurement error and reduced reproducibility compared with the forefoot.