Severity of rotator cuff disorders and additional load affect fluoroscopy-based shoulder kinematics during arm abduction.

BACKGROUND: Rotator cuff disorders, whether symptomatic or asymptomatic, may result in abnormal shoulder kinematics (scapular rotation and glenohumeral translation). This study aimed to investigate the effect of rotator cuff tears on in vivo shoulder kinematics during a 30° loaded abduction test using single-plane fluoroscopy. MATERIALS AND METHODS: In total, 25 younger controls, 25 older controls and 25 patients with unilateral symptomatic rotator cuff tears participated in this study. Both shoulders of each participant were analysed and grouped on the basis of magnetic resonance imaging into healthy, rotator cuff tendinopathy, asymptomatic and symptomatic rotator cuff tears. All participants performed a bilateral 30° arm abduction and adduction movement in the scapular plane with handheld weights (0, 2 and 4 kg) during fluoroscopy acquisition. The range of upward-downward scapular rotation and superior-inferior glenohumeral translation were measured and analysed during abduction and adduction using a linear mixed model (loads, shoulder types) with random effects (shoulder ID). RESULTS: Scapular rotation was greater in shoulders with rotator cuff tendinopathy and asymptomatic rotator cuff tears than in healthy shoulders. Additional load increased upward during abduction and downward during adduction scapular rotation (P < 0.001 in all groups but rotator cuff tendinopathy). In healthy shoulders, upward scapular rotation during 30° abduction increased from 2.3° with 0-kg load to 4.1° with 4-kg load and on shoulders with symptomatic rotator cuff tears from 3.6° with 0-kg load to 6.5° with 4-kg load. Glenohumeral translation was influenced by the handheld weights only in shoulders with rotator cuff tendinopathy (P ≤ 0.020). Overall, superior glenohumeral translation during 30° abduction was approximately 1.0 mm with all loads. CONCLUSIONS: The results of glenohumeral translation comparable to control but greater scapular rotations during 30° abduction in the scapular plane in rotator cuff tears indicate that the scapula compensates for rotator cuff deficiency by rotating. Further analysis of load-dependent joint stability is needed to better understand glenohumeral and scapula motion. LEVEL OF EVIDENCE: Level 2. TRIAL REGISTRATION: Ethical approval was obtained from the regional ethics committee (Ethics Committee Northwest Switzerland EKNZ 2021-00182), and the study was registered at clinicaltrials.gov on 29 March 2021 (trial registration number NCT04819724, https://clinicaltrials.gov/ct2/show/NCT04819724 ).

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).

Classification of inertial sensor-based gait patterns of orthopaedic conditions using machine learning: A pilot study.

Elderly patients often have more than one disease that affects walking behavior. An objective tool to identify which disease is the main cause of functional limitations may aid clinical decision making. Therefore, we investigated whether gait patterns could be used to identify degenerative diseases using machine learning. Data were extracted from a clinical database that included sagittal joint angles and spatiotemporal parameters measured using seven inertial sensors, and anthropometric data of patients with unilateral knee or hip osteoarthritis, lumbar or cervical spinal stenosis, and healthy controls. Various classification models were explored using the MATLAB Classification Learner app, and the optimizable Support Vector Machine was chosen as the best performing model. The accuracy of discrimination between healthy and pathologic gait was 82.3%, indicating that it is possible to distinguish pathological from healthy gait. The accuracy of discrimination between the different degenerative diseases was 51.4%, indicating the similarities in gait patterns between diseases need to be further explored. Overall, the differences between pathologic and healthy gait are distinct enough to classify using a classical machine learning model; however, routinely recorded gait characteristics and anthropometric data are not sufficient for successful discrimination of the degenerative diseases.

Association Between Weightbearing CT and MRI Findings in Progressive Collapsing Foot Deformity.

BACKGROUND: Weightbearing computed tomography (WBCT) scans allow for a better understanding of foot alignment in patients suffering from progressive collapsing foot deformity (PCFD). However, soft tissue integrity (eg, spring ligament complex or tibialis posterior tendon) cannot be easily assessed via WBCT. As performing both WBCT and magnetic resonance imaging (MRI) might not be cost effective, we aimed to assess whether there is an association between osseous and soft tissue findings in WBCT and MRI. METHODS: In this observational study, a consecutive cohort of 24 patients of various stages of PCFD (mean age 51 ± 18 years) underwent WBCT scans and MRI. Twenty-four healthy individuals of similar age, body mass index (BMI), and sex with WBCT scans were used as a control group. In addition to of osseous sinus tarsi impingement, 4 commonly used 3-dimensional (3D) measurements (talocalcaneal overlap [TCO], talonavicular coverage [TNC], Meary angle [MA], axial/lateral) were obtained using a dedicated postprocessing software (DISIOR 2.1, Finland) on the WBCT data sets. Sinus tarsi obliteration, spring ligament complex, tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P < .05) correlation between findings. RESULTS: None of the assessed 3D measurements correlated with either spring ligament complex or tibiospring ligament tears. BMI and TCO were found to be associated with tibialis posterior tendon tears. Seventy-five percent of patients with osseous sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI. CONCLUSION: Although WBCT reflects foot alignment and can reveal osseous sinus tarsi impingement in PCFD patients, the association between WBCT-based 3D measurements and ligament or tendon tears assessed via MRI is limited. WBCT appears complimentary to MRI regarding its diagnostic value. Both imaging options add important information and may impact decision making in the treatment of PCFD patients. LEVEL OF EVIDENCE: Level IV, observational study.

Gait function assessed using 3D gait analysis in patients with cervical spinal myelopathy before and after surgical decompression: a systematic review and meta-analysis.

BACKGROUND: Degenerative cervical myelopathy (DCM) is the most common cause of cervical spinal cord dysfunction in adults and the result of chronic degenerative changes of the cervical spine. The compression of the spinal cord can lead to ischemia, inflammation, and neuronal apoptosis with a consequent impairment of the neurological function. Gait impairment is one of the most frequent signs of DCM. PURPOSE: To investigate the changes in spatio-temporal gait parameters assessed using 3D gait analysis in patients affected by DCM compared with healthy controls and the effect of surgical decompression on these parameters. STUDY DESIGN/SETTING: Systematic review and meta-analysis. PATIENT SAMPLE: The meta-analysis included 267 patients with DCM and 276 healthy controls. OUTCOME MEASURES: Spatio-temporal parameters of gait were assessed. The primary outcome was gait speed; the secondary outcomes were cadence, stride length, step width, stride time, single-limb support time, and double-limb support time. METHODS: Studies reporting spatial and/or temporal gait parameters measured using 3D gait analysis in patients with DCM were included. Data sources were Embase, Medline, and the Core Collection of Web of Science. Meta-analyses were performed to investigate the influence of surgical decompression in patients measured before and after surgery as well as to compare gait parameters of patients with DCM with controls. RESULTS: Thirteen studies reporting on 267 patients with DCM and 276 healthy controls met the inclusion criteria. Seven studies compared patients with DCM with healthy controls, three studies compared gait in patients with DCM before and after surgical decompression, and three studies performed both comparisons. Compared with healthy controls, patients with DCM had slower gait speed (Standardized Mean Difference (SMD), -1.49; 95% confidence interval (CI) [-1.86; -1.13]; p<.001), lower cadence (SMD, -0.78; 95%CI [-1.00; -0.56]; p<.001), shorter stride length (SMD, -1.27; 95%CI [-1.53, -1.01]; p<.001), greater step width (SMD, 0.98; 95%CI [0.42, 1.54]; p=.003), longer stride time (SMD, 0.77; 95%CI [0.37, 1.16]; p=.009), single-limb support phase (SMD, -0.68; 95%CI [-1.06; -0.29]; p=.011), and double-limb support phase (SMD 0.84; 95%CI [0.35, 1.32]; p=.012). After surgical decompression, patients with DCM showed an improvement in gait speed (SMD, 0.57 (95%CI [0.29; 0.85]; p=.003) and no significant differences in other spatio-temporal parameters. CONCLUSIONS: Patients with DCM have clearly different spatio-temporal gait parameters than healthy controls. Gait speed is the only spatio-temporal gait parameter that improves significantly after surgical decompression suggesting that gait speed may be an important clinical outcome parameter in patients with DCM.

Is Age a Risk Factor for Early Postoperative Cage Subsidence After Transforaminal Lumbar Interbody Fusion? A Retrospective Study in 170 Patients.

STUDY DESIGN: Retrospective observational study. OBJECTIVES: We aim to evaluate whether age is a risk factor for cage subsidence, and whether other patient characteristics, preoperative radiological or imaging parameters are associated with cage subsidence and the need for revision surgery in patients undergoing transforaminal lumbar interbody fusion (TLIF). METHODS: Patient demographics and surgery-related information were extracted. Cage subsidence was evaluated using upright standing sagittal plane X-rays and defined as more than 2 mm migration of the cage into the adjacent vertebral body. Patients who received revision surgery within 1 year for any reason were recorded. Radiographic parameters were measured. Univariable logistic regression models were used to evaluate the risk factors for cage subsidence and need for revision surgery. RESULTS: At 3-month and 1-year follow-up, cage subsidence was observed in 28 patients (16.5%) and 58 patients (34.1%), respectively. Twenty-seven patients received revision surgery within the first year after TLIF. Age (odds ratio (OR): 1.07 per year) and male sex (OR: 2.76) had a significantly increased odds ratio for cage subsidence 3 months after TLIF. Male sex (OR: 2.55) but not age was a significant risk factor for cage subsidence 1 year after TLIF. Of all assessed risk factors, only BMI (OR: 1.11 per kg/m2) had a significantly increased risk for the need of revision surgery. CONCLUSIONS: Age was associated with cage subsidence 3 months but not 1 year after TLIF suggesting that age is only a risk factor for early cage subsidence and not in a longer follow-up.

Ambulatory knee biomechanics and muscle activity 2 years after ACL surgery: InternalBraceTM-augmented ACL repair versus ACL reconstruction versus healthy controls.

BACKGROUND: Little is known about knee mechanics and muscle control after augmented ACL repair. Our aim was to compare knee biomechanics and leg muscle activity during walking between the legs of patients 2 years after InternalBraceTM-augmented anterior cruciate ligament repair (ACL-IB) and between patients after ACL-IB and ACL reconstruction (ACL-R), and controls. METHODS: Twenty-nine ACL-IB, 27 sex- and age-matched ACL-R (hamstring tendon autograft) and 29 matched controls completed an instrumented gait analysis. Knee joint angles, moments, power, and leg muscle activity were compared between the involved and uninvolved leg in ACL-IB (paired t-tests), and between the involved legs in ACL patients and the non-dominant leg in controls (analysis of variance and posthoc Bonferroni tests) using statistical parametric mapping (SPM, P < 0.05). Means and 95% confidence intervals (CI) of differences in discrete parameters (DP; i.e., maximum/minimum) were calculated. RESULTS: Significant differences were observed in ACL-IB only in minimum knee flexion angle (DP: 2.4°, CI [-4.4;-0.5]; involved > uninvolved) and maximum knee flexion moment during stance (-0.07Nm/kg, CI [-0.13;-0.00]; involved < uninvolved), and differences between ACL-IB and ACL-R only in maximum knee flexion during swing (DP: 3.6°, CI [0.5;7.0]; ACL-IB > ACL-R). Compared to controls, ACL-IB (SPM: 0-3%GC, P = 0.015; 98-100%, P = 0.016; DP: -6.3 mm, CI [-11.7;-0.8]) and ACL-R (DP: -6.0 mm, CI [-11.4;-0.2]) had lower (maximum) anterior tibia position around heel strike. ACL-R also had lower maximum knee extension moment (DP: -0.13Nm/kg, CI [-0.23;-0.02]) and internal knee rotation moment (SPM: 34-41%GC, P < 0.001; DP: -0.03Nm/kg, CI [-0.06;-0.00]) during stance, and greater maximum semitendinosus activity before heel strike (DP: 11.2%maximum voluntary contraction, CI [0.1;21.3]) than controls. CONCLUSION: Our results suggest comparable ambulatory knee function 2 years after ACL-IB and ACL-R, with ACL-IB showing only small differences between legs. However, the differences between both ACL groups and controls suggest that function in the involved leg is not fully recovered and that ACL tear is not only a mechanical disruption but also affects the sensorimotor integrity, which may not be restored after surgery. The trend toward fewer abnormalities in knee moments and semitendinosus muscle function during walking after ACL-IB warrants further investigation and may underscore the importance of preserving the hamstring muscles as ACL agonists. LEVEL OF EVIDENCE: Level III, case-control study. TRIAL REGISTRATION: clinicaltrials.gov, NCT04429165 (12/06/2020).

The role of muscle degeneration and spinal balance in the pathophysiology of lumbar spinal stenosis: Study protocol of a translational approach combining in vivo biomechanical experiments with clinical and radiological parameters.

OBJECTIVE: To describe a study protocol for investigating the functional association between posture, spinal balance, ambulatory biomechanics, paraspinal muscle fatigue, paraspinal muscle quality and symptoms in patients with symptomatic lumbar spinal stenosis (sLSS) before and 1-year after elective surgical intervention. DESIGN: Single-centre prospective, experimental, multimodal (clinical, biomechanical, radiological) study with three instances of data collection: baseline (study visit 1), 6-month follow-up (remote) and 1-year follow-up (study visit 2). Both study visits include an in vivo experiment aiming to elicit paraspinal muscle fatigue for postural assessment in a non-fatigued and fatigued state. EXPERIMENTAL PROTOCOL: At baseline and 1-year follow-up, 122 patients with sLSS will be assessed clinically, perform the back-performance scale assessment and complete several patient-reported outcome measure (PROMs) questionnaires regarding overall health, disease-related symptoms and kinesiophobia. Posture and biomechanical parameters (joint kinematics, kinetics, surface electromyography, back curvature) will be recorded using an optoelectronic system and retroreflective markers during different tasks including overground walking and movement assessments before and after a modified Biering-Sørensen test, used to elicit paraspinal muscle fatigue. Measurements of muscle size and quality and the severity of spinal stenosis will be obtained using magnetic resonance imaging (MRI) and sagittal postural alignment data from EOS radiographies. After each study visit, physical activity level will be assessed during 9 days using a wrist-worn activity monitor. In addition, physical activity level and PROMs will be assessed remotely at 6-month follow-up. CONCLUSION: The multimodal set of data obtained using the study protocol described in this paper will help to expand our current knowledge on the pathophysiology, biomechanics, and treatment outcome of degenerative sLSS. The results of this study may contribute to defining and/or altering patient treatment norms, surgery indication criteria and post-surgery rehabilitation schedules. TRIAL REGISTRATION: The protocol was approved by the regional ethics committee and has been registered at clinicaltrials.gov (NCT05523388).

Favorable Patient-Reported, Clinical, and Functional Outcomes 2 Years After ACL Repair and InternalBrace Augmentation Compared With ACL Reconstruction and Healthy Controls.

BACKGROUND: Recently, interest in anterior cruciate ligament (ACL) preservation and repair after proximal ACL tears has been resurrected. Although good clinical outcomes have been reported in the literature with adequate patient selection, to date detailed scientific evidence for the functional benefit of primary ACL repair with ligament augmentation is scarce. PURPOSE: To compare patient-reported, clinical, and functional outcomes in patients 2 years after ACL repair and InternalBrace augmentation (ACL-IB) with age- and sex-matched patients 2 years after ACL reconstruction (ACL-R) and with matched healthy controls. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: In total, 29 patients 2 years after ACL-IB, 27 sex- and age- matched patients 2 years after ACL-R (hamstring autografts), and 29 matched healthy controls were included. Patient-reported outcomes were assessed using the International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, EQ-5D-5L, Tegner Activity Scale, and Anterior Cruciate Ligament Return to Sports after Injury scale. Surgery time was recorded. For clinical outcomes, range of motion and thigh and shank circumference were measured, and passive anterior translation was determined using the Rolimeter. Isokinetic muscle strength was measured using a Biodex dynamometer. The limb symmetry index (operated/contralateral or nondominant/dominant × 100), side-to-side differences (operated - contralateral, nondominant - dominant), and hamstring-quadriceps ratios were calculated for functional parameters. Failure and reoperation rates were not compared. RESULTS: Two years after surgery, patients treated with ACL-IB showed good to excellent patient-reported outcomes comparable with those of patients after ACL-R. Surgery time, including concomitant surgeries, was significantly shorter in the ACL-IB group (mean, 81 minutes) compared with the ACL-R group (mean, 97 minutes) (P = .024). Isokinetic muscle strength was comparable between patient groups without significant differences in extensor and flexor strength or in hamstring-quadriceps ratios. CONCLUSION: These results suggest that ACL-IB achieves comparable patient-reported, clinical, and functional outcomes with ACL-R at 2 years postoperatively and, after careful patient selection, should be considered as a valuable early treatment alternative for proximal ACL tears. REGISTRATION: NCT04429165 (ClinicalTrials.gov identifier).

Functional leg performance 2 years after ACL surgery: a comparison between InternalBrace™-augmented repair versus reconstruction versus healthy controls.

BACKGROUND: While clinical and patient-reported outcomes have been investigated in patients after InternalBrace™-augmented anterior cruciate ligament repair (ACL-IB), less is known regarding restoration of functional performance. We aimed to determine differences in functional performance within and between patients 2 years after ACL-IB, patients 2 years after ACL reconstruction (ACL-R), and healthy controls. MATERIALS AND METHODS: A total of 29 ACL-IB, 27 ACL-R (hamstring autograft), and 29 controls performed single-leg hop (maximum forward distance hop, SLH; side hop > 40 cm in 30 s, SH), proprioception (knee joint position sense at 30° and 60° flexion), and dynamic postural balance (Y Balance) tests. Differences were calculated within groups (side-to-side difference) and between the involved leg of patients and the non-dominant leg of controls, and were evaluated to predefined statistical (P < 0.05), clinically relevant, and methodological (smallest detectable change) thresholds. The number of exceeded thresholds represented no (0), small (1), moderate (2), or strong (3) differences. In addition, the relative number of participants achieving leg symmetry (≥ 90%) and normal performance (≥ 90% of the average performance of the non-dominant leg of controls) were compared between groups (chi-squared tests, P < 0.05). RESULTS: We observed no-to-moderate leg differences within ACL-IB (moderate difference in hops) and within ACL-R (moderate difference in knee proprioception), no leg differences between patient groups, no-to-small leg differences between ACL-IB and controls, and no leg differences between ACL-R and controls in functional performance. However, two patients in ACL-IB and ACL-R, respectively, passed the hop pretest only with their uninvolved leg, and fewer patients after ACL-IB and ACL-R than controls reached a leg symmetry and normal leg performance of controls in SLH (P < 0.001). CONCLUSIONS: Functional performance seems to be comparable 2 years postoperatively between ACL-IB and ACL-R for a specific subgroup of patients (i.e., proximal ACL tears, moderate activity level). However, the presumed advantage of comparable functional outcome with preserved knee structures after augmented ACL repair compared with ACL-R, and the tendency of both patient groups toward leg asymmetry and compromised single-leg hop performance in the involved legs, warrants further investigation. Level of Evidence Level III, case-control study. Trial registration clinicaltrials.gov, NCT04429165 (12/09/2020). Prospectively registered, https://clinicaltrials.gov/ct2/show/NCT04429165 .

Load-induced increase in muscle activity during 30° abduction in patients with rotator cuff tears and control subjects.

BACKGROUND: Rotator cuff muscles stabilise the glenohumeral joint and contribute to the initial abduction phase with other shoulder muscles. This study aimed to determine if the load-induced increase in shoulder muscle activity during a 30° abduction test is influenced by asymptomatic or symptomatic rotator cuff pathologies. MATERIALS AND METHODS: Twenty-five patients with unilateral rotator cuff tears (age, 64.3 ± 10.2 years), 25 older control subjects (55.4 ± 8.2 years) and 25 younger control subjects (26.1 ± 2.3 years) participated in this study. Participants performed a bilateral 30° arm abduction and adduction movement in the scapular plane with handheld weights (0-4 kg). Activity of the deltoid, infraspinatus, biceps brachii, pectoralis major, latissimus dorsi and upper trapezius muscles was analysed at maximum abduction angle after normalisation to maximum voluntary contraction. Shoulders were classified into rotator cuff tendinopathy, asymptomatic and symptomatic rotator cuff tears, and healthy based on magnetic resonance images. A linear mixed model (loads, shoulder types) with random effects (shoulder identification) was applied to the log-transformed muscle activities. RESULTS: Muscle activity increased with increasing load in all muscles and shoulder types (P < 0.001), and 1-kg increments in additional weights were significant (P < 0.001). Significant effects of rotator cuff pathologies were found for all muscles analysed (P < 0.05). In all muscles, activity was at least 20% higher in symptomatic rotator cuff tears than in healthy shoulders (P < 0.001). Symptomatic rotator cuff tears showed 20-32% higher posterior deltoid (P < 0.05) and 19-25% higher pectoralis major (P < 0.01) activity when compared with asymptomatic tears. CONCLUSIONS: Rotator cuff pathologies are associated with greater relative activity of shoulder muscles, even with low levels of additional load. Therefore, the inclusion of loaded shoulder tests in the diagnosis and rehabilitation of rotator cuff pathologies can provide important insight into the functional status of shoulders and can be used to guide treatment decisions. LEVEL OF EVIDENCE: Level 2. TRIAL REGISTRATION: Ethical approval was obtained from the regional ethics committee (Ethics Committee Northwest Switzerland EKNZ 2021-00182), and the study was registered at clinicaltrials.gov on 29 March 2021 (trial registration number NCT04819724, https://clinicaltrials.gov/ct2/show/NCT04819724 ).

Distal femoral osteotomy for the valgus knee: indications, complications, clinical and radiological outcome.

INTRODUCTION: The aim of this study was to describe the indications and technical aspects of medial closing and lateral opening distal femoral osteotomy (MCDFO and LODFO) for patients with a valgus knee and to report clinical and radiological outcomes and complications. METHODS: Over 6 years, 28 DFOs (22 MCDFO, 6 LODFO) were performed in 22 Patients. In this cohort study, we retrospectively analyzed clinical and radiological outcome measures as well as complications. RESULTS: The median (range) age was 47 (17-63) years, height 1.68 (1.56-1.98) m, body mass 80 (49-105) kg, and body mass index (BMI) 27.4 (18.6-37.0) kg/m2. The clinical follow-up was 21 (7-81) months, the need for total or unicompartmental knee arthroplasty (TKA/UKA) and hardware removal was followed up for 59 (7-108) months postoperatively. Preoperatively, hip-knee-ankle angle (HKA, negative values denote varus) was 7.0 (2.0-13.0)°, mechanical lateral distal femoral angle (mLDFA) was 83.7 (79.9-88.2)°, and mechanical proximal tibial angle (MPTA) was 89.0 (86.6-94.5)°. Postoperatively, HKA was -1.3 (-9.0-1.2)° and mLDFA was 90.8 (87.3-97.3)°. The incidence of minor and major complications was 25% and 14%, the incidence of delayed and nonunion was 18% and 4%, respectively. At the last follow-up, 18% of the patients had pain at rest, 25% during activities of daily living, and 39% during physical activity, and 71% were satisfied with the outcome. 7% of the cases received a TKA/UKA, 71% received a hardware removal. CONCLUSION: DFO is a reasonable treatment for lateral osteoarthritis in younger patients to avoid disease progression and the need for an UKA/TKA. However, there is a long rehabilitation time, a considerable risk for complications, and a high need for hardware removal. While many patients experienced symptoms at the long-term follow-up, most were satisfied with the outcome. Appropriate patient information is essential. Level of evidence Level IV, Case Series. Trial registration number NCT04382118, clinicaltrials.gov, May 11, 2020.

Effect of load carriage on joint kinematics, vertical ground reaction force and muscle activity: Treadmill versus overground walking.

BACKGROUND: Previous studies have investigated the effect of either different load or different surface conditions, such as overground or treadmill walking, on human biomechanics. However, studies combining these two aspects are scarce. RESEARCH QUESTION: The purpose of this study was to quantify the difference in spatiotemporal parameters, lower extremity joint kinematics, vertical ground reaction forces (vGRF) and muscle activity between normal bodyweight (100 %BW) and 20 % increased bodyweight (120 %BW) during overground and treadmill walking. METHODS: Ten healthy young adults walked overground at self-selected speed and on an instrumented treadmill set to the overground speed. Spatiotemporal parameters, 3-dimensional lower extremity kinematics, vGRF and muscle activity were measured and compared between conditions. RESULTS: The stance phase was longer for 120 %BW than 100 %BW in both overground and treadmill walking. Further, the stance phase was longer and cadence higher in treadmill than overground walking for both load conditions. Knee flexion angles were more than 3° greater in the second half of swing in treadmill than in overground walking. The vGRF was higher for 120 %BW compared to 100 %BW on both surfaces (treadmill, first peak: +18.6 %BW; second peak: +13.5 %BW; overground, first peak: +22.2 %BW; second peak: +19.8 %BW). Differences between conditions greater than 20 % were observed in short periods during the gait cycle for vastus medialis, vastus lateralis and semitendinosus. SIGNIFICANCE: Results regarding the effects of carrying additional load using a weight vest on joint kinematics during treadmill walking may be translated to overground walking but some changes in muscle activation can be expected.

Test-retest reliability of isometric shoulder muscle strength during abduction and rotation tasks measured using the Biodex dynamometer.

BACKGROUND: The Constant score (CS) is often used clinically to assess shoulder function and includes a muscle strength assessment only for abduction. The aim of this study was to evaluate the test-retest reliability of isometric shoulder muscle strength during various positions of abduction and rotation with the Biodex dynamometer and to determine their correlation with the strength assessment of the CS. METHODS: Ten young healthy subjects participated in this study. Isometric shoulder muscle strength was measured during 3 repetitions for abduction at 10° and 30° abduction in the scapular plane (with extended elbow and hand in neutral position) and for internal and external rotation (with the arm at 15° abduction in the scapular plane and elbow flexed at 90°). Muscle strength tests with the Biodex dynamometer were measured in 2 different sessions. The CS was acquired only in the first session. Intraclass correlation coefficients (ICCs) with 95% confidence interval, limits of agreement, and paired t tests for repeated tests of each abduction and rotation task were calculated. Pearson's correlation between the strength parameter of the CS and isometric muscle strength was investigated. RESULTS: Muscle strength did not differ between tests (P > .05) with good to very good reliabilities for abduction at 10° and 30°, external rotation and internal rotation (ICC >0.7 for all). A moderate correlation of the strength parameter of the CS with all isometric shoulder strength parameters was observed (r > 0.5 for all). CONCLUSION: Shoulder muscle strength for abduction and rotation measured with the Biodex dynamometer are reproducible and correlate with the strength assessment of the CS. Therefore, these isometric muscle strength tests can be further employed to investigate the effect of different shoulder joint pathology on muscle strength. These measurements consider a more comprehensive functionality of the rotator cuff than the single strength evaluation in abduction within the CS as both abduction and rotation are assessed. Potentially, this would allow for a more precise differentiation between the various outcomes of rotator cuff tears.

Modified surgical anchor refixation in older patients with acute proximal hamstring rupture: clinical outcome, patient satisfaction and muscle strength.

INTRODUCTION: After conventional surgical refixation of the hamstrings after proximal hamstring rupture, patients frequently experience pain while sitting and deficits in hamstring muscle strength of the operated side. To improve these outcomes, we have modified the surgical anchor placement and have carried out a thorough follow-up examination. MATERIALS AND METHODS: Thirteen older patients (8 female, 5 males) with a median age of 64.2 (range, 52.1-80.4) years were surgically treated for acute proximal hamstring rupture using modified anchor placement and participated in a follow-up assessment at a median of 46.2 (11.2-75.0) months after surgery. Patients completed the Perth Hamstring Assessment Tool (PHAT), quality of life questionnaire (EQ-5D-5L) and the Lower Extremity Functional Scale (LEFS), and rated their satisfaction level on a scale from 0 to 100%. Local tenderness on the ischial tuberosity and maximum passive hip flexion were measured on both limbs. Maximum isokinetic knee flexor muscle strength was measured bilaterally using a dynamometer. RESULTS: The median (range) PHAT, EQ-5D-5L and LEFS score were 78.8/100 (54.6-99.8), 0.94/1 (0.83-1) and 88.75/100 (61.25-100). The median satisfaction was 100% (90-100%). Only one patient felt discomfort when the ischial tuberosity was palpated. Neither maximum passive hip flexion nor maximum isokinetic flexor muscle strength differed between the operated and non-operated side (P > 0.58). Clinical scores did not correlate with the leg symmetry index of knee flexor muscle strength (Spearman's rho < 0.448, P > 0.125). There were no tendon re-ruptures, or postoperative sciatic radiculopathy, at the time of follow-up. CONCLUSIONS: The modified extra-anatomical anchor placement resulted in good clinical and functional outcome of surgical repair of acute proximal hamstring rupture. Especially the absence of postoperative pain while sitting and the comparable muscle strength to the contralateral side is promising. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04867746, registered.

High tibial osteotomy effectively redistributes compressive knee loads during walking.

The objectives of this study were to estimate pre- and postoperative lower limb kinematics and kinetics and knee intra-articular forces during gait using musculoskeletal modeling in a cohort of patients with knee osteoarthritis (OA) undergoing high tibial osteotomy (HTO), compare these to controls, and determine correlations between changes in these parameters and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscores after HTO. Sixteen patients with isolated, symptomatic medial compartment knee OA completed pre- and postoperative gait analysis (mean follow-up time: 8.6 months). Sixteen age- and sex-matched asymptomatic volunteers participated as controls. Musculoskeletal modeling was used to evaluate lower limb joint moments and knee contact forces during gait. While HTO had limited influence on sagittal plane kinematics and moments, significant changes in the load distribution at the knee after HTO were observed with a lower postoperative compressive load on the medial compartment during midstance and a higher compressive load on the lateral compartment during early and late stance. Moreover, the lateral shear force in midstance was significantly lower after HTO. Changes in the external knee adduction moment (KAM) did not always coincide with reductions in the knee compressive force in the medial compartment. Biomechanical changes did not correlate with improvements in KOOS subscores. Hence, HTO effectively unloaded the medial compartment by redistributing part of the overall compressive force to the lateral compartment during gait with limited influence on gait function. The KAM may not adequately describe compartmental load magnitude or changes induced by interventions at the compartment level. Clinical trial registration: ClinicalTrials. gov Identifier-NCT02622204. Clinical significance: This study provides important evidence for changes in joint level loads after corrective osteotomy as joint preserving surgery and emphasizes the need for additional biomechanical outcomes of such interventions.

Functional assessment of total hip arthroplasty using inertial measurement units: Improvement in gait kinematics and association with patient-reported outcome measures.

Inertial measurement units (IMUs) are commonly used for gait assessment, yet their potential for quantifying improvements in gait function and patterns after total hip arthroplasty (THA) has not been fully explored. The primary aim of this study was to compare spatiotemporal parameters and sagittal plane kinematic patterns of patients with hip osteoarthritis (OA) before and after THA, and to asymptomatic controls. The secondary aim was to assess the association between dynamic hip range of motion (ROM) during walking and the Hip Osteoarthritis Outcome Scores (HOOS). Twenty-four patients with hip OA and 24 matched asymptomatic controls completed gait analyses using the RehaGait® sensor system. Patients were evaluated pre- and 1 year postoperatively, controls in a single visit. Differences in kinematic data were analyzed using statistical parametric mapping, and correlations between dynamic hip ROM and HOOS were calculated. Walking speed and stride length significantly increased (+0.08 m/s, p = 0.019; +0.06 m, p = 0.048) after THA but did not reach the level of asymptomatic controls (-0.11 m/s, p = 0.028; -0.14 m, p = 0.001). Preoperative hip and knee kinematics differed significantly from controls. After THA, they improved significantly and did not differ from controls. Dynamic hip flexion-extension ROM correlated positively with all HOOS subscores (r > 0.417; p ≤ 0.001). The change in HOOS symptoms in patients was explained by the combination of baseline HOOS symptoms and change in dynamic hip ROM (r2 = 0.748) suggesting that the additional information gained with IMU gait analysis helps to complement and objectify patient-reported outcome measures pre- and postoperatively and monitor treatment-related improvements.

Kinematics and paraspinal muscle activation patterns during walking differ between patients with lumbar spinal stenosis and controls.

BACKGROUND: The narrowing of the spinal canal due to degenerative processes may lead to symptomatic lumbar spinal stenosis (sLSS) and impairments in the patients' gait. Changes in lower extremity joint kinematics and trunk flexion angles have been reported, yet less is known about muscle activation patterns of paraspinal and gluteal muscles in patients with sLSS compared to healthy participants. RESEARCH QUESTION: Do muscle activation patterns together with sagittal joint kinematics differ between patients with sLSS and healthy controls and do these differences-quantified using gait scores-correlate with clinical scores? METHODS: In 20 patients with sLSS scheduled for surgery and 19 healthy participants, gait was assessed using seven inertial sensors and muscle activation of gluteus medius, erector spinae and multifidus using wireless surface electromyography (EMG). Differences in joint kinematics and EMG patterns were assessed using statistical parametric mapping with non-parametric independent sample t tests (P < 0.05). Gait scores that describe the overall deviation in joint angles (mGPS) and muscle activation patterns (EMG-Profile Score) were calculated as root mean square distances between patients and healthy participants and their associations with clinical scores (pain, Oswestry Disability Score (ODI)) were analyzed using Spearman's correlation coefficients rho (P < 0.05). RESULTS: Patients had larger mGPS (+1.9°) and EMG-Profile Scores (+50%) and walked on average slower (-0.26 m/s) than controls. EMG patterns revealed higher activation of multifidus, erector spinae and gluteus medius during midstance in patients compared to controls. Clinical scores (pain, ODI) did not correlate with mGPS or EMG-Profile Scores within patients. SIGNIFICANCE: Observed differences in gait and muscle activation patterns and in the summary scores of gait and EMG deviations between patients with sLSS and healthy controls may represent additional functional outcomes reflecting the functional status of patients that can be measured using wearable sensors and hence is suitable for application in clinical practice.

Load-Induced Glenohumeral Translation After Rotator Cuff Tears: Protocol for an In Vivo Study.

BACKGROUND: Rotator cuff tears are a common shoulder injury, but they sometimes remain undiagnosed, as symptoms can be limited. Altered shoulder biomechanics can lead to secondary damage and degeneration. In biomechanical analyses, the shoulder (ie, the glenohumeral joint) is normally idealized as a ball-and-socket joint, even though a translation is often observed clinically. To date, no conclusive changes in glenohumeral translation have been reported in patients with rotator cuff tears, and it is unknown how an additional handheld weight that is comparable to those used during daily activities will affect glenohumeral translations in patients with rotator cuff tears. OBJECTIVE: This study aims to assess the load-induced glenohumeral translation (liTr) in patients with rotator cuff tears and its association with the load-induced changes in muscle activation (liMA). METHODS: Patients and asymptomatic controls will be recruited. Participants will fill out health questionnaires and perform 30° arm abduction and adduction trials, during which they will hold different handheld weights of a maximum of 4 kg while motion capture and electromyographic data are collected. In addition, fluoroscopic images of the shoulders will be taken for the same movements. Isometric shoulder muscle strength for abduction and rotation will be assessed with a dynamometer. Finally, shoulder magnetic resonance images will be acquired to assess muscle status and injury presence. The dose-response relationship between additional weight, liTr, and liMA will be evaluated. RESULTS: Recruitment and data collection began in May 2021, and they will last until the recruitment target is achieved. Data collection is expected to be completed by the end of 2022. As of November 2022, data processing and analysis are in progress, and the first results are expected to be submitted for publication in 2023. CONCLUSIONS: This study will aid our understanding of biological variations in liTr, the influence of disease pathology on liTr, the potential compensation of rotator cuff tears by muscle activation and size, and the association between liTr and patient outcomes. The outcomes will be relevant for diagnosis, treatment, and rehabilitation planning in patients with rotator cuff tears. TRIAL REGISTRATION: ClinicalTrials.gov NCT04819724; https://clinicaltrials.gov/ct2/show/NCT04819724. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/43769.

Dose-response relationship of in vivo ambulatory load and mechanosensitive cartilage biomarkers-The role of age, tissue health and inflammation: A study protocol.

OBJECTIVE: To describe a study protocol for investigating the in vivo dose-response relationship between ambulatory load magnitude and mechanosensitive blood markers of articular cartilage, the influence of age, cartilage tissue health and presence of inflammation on this relationship, and its ability to predict changes in articular cartilage quality and morphology within 2 years. DESIGN: Prospective experimental multimodal (clinical, biomechanical, biological) data collection under walking stress and three different load conditions varied in a randomized crossover design. EXPERIMENTAL PROTOCOL: At baseline, equal numbers of healthy and anterior cruciate ligament injured participants aged 20-30 or 40-60 years will be assessed clinically and complete questionnaires regarding their knee health. Biomechanical parameters (joint kinetics, joint kinematics, and surface electromyography) will be recorded while performing different tasks including overground and treadmill walking, single leg balance and hopping tasks. Magnetic resonance images (MRI) of both of knees will be obtained. On separate stress test days, participants will perform a 30-minute walking stress with either reduced (80% body weight (BW)), normal (100%BW) or increased (120%BW) load. Serum blood samples will be taken immediately before, immediately after, 30, 120 and 210 minutes after the walking stress. Concentration of articular cartilage blood biomarkers will be assessed using enzyme linked immunosorbent assays. At 24-month follow-up, participants will be again assessed clinically, undergo an MRI, complete questionnaires, and have a blood sample taken. CONCLUSION: The study design provides a standardized set up that allows to better understand the influence of ambulatory load on articular cartilage biomarkers and thereby extend current knowledge on in vivo cartilage metabolism and mechanosensitivity. Further, this study will help to elucidate the prognostic value of the load-induced cartilage biomarker response for early articular cartilage degeneration. TRIAL REGISTRATION: The protocol was approved by the regional ethics committee and has been registered at clinicaltrials.gov (NCT04128566).