Background. Revision total knee arthroplasties (rTKA) are performed with increasing frequency due to the increasing numbers of primary arthroplasties, but very little is known regarding the influence of muscle strength impairments on functional limitations in this population. Objectives. The aim of this study was to assess relationship between muscle strength and functional level in patient with rTKA. Design and Methods. Twenty-three patients (8 males, 15 females) were included in the study with mean age 68.4±10 years. Patients performed 3 performance tests (50-Step Walking Test, 10 Meter Walk Test, 30-Second Chair-Stand Test), and one self-report test (HSS) were preferred to assess patients. The maximum isometric muscle strength of quadriceps femoris and hamstring muscles of all the patients was measured using Hand-Held Dynamometer (HHD). Results. While moderate-to-strong significant correlations was found between quadriceps femoris muscle strength and 30- Second Chair-Stand Test (r=0.390, p=0.049), 50-Step Walking Test (r=−0.530, p=0.005), 10 Meter Walk Test (r=−0.587, p=0.002), there were not significant correlation between HSS knee score and all performance-based tests (p>0.05). Also there were not significant correlation between hamstring muscle strength and all other measurement tests (p>0.05). Conclusion. The moderate-to-strong statistical significant correlation between quadriceps femoris muscle strength and functional performance tests suggests that improved postoperative quadriceps strengthening could be important to enhance the potential benefits of rTKA

Purpose. Investigating the effects of femoral stem length on hip and knee muscle strength. Methods. The study included 20 patients having undergone total knee prostheses (TKP) due to coxarthrosis and 10 healthy subjects. Of the 20 patients, 10 underwent conventional TKP and 10 had Thrust Plate Prothesis (TPP). For the assessment of the patients’ muscle strength of operated and non-operated hips (Gl. medius and Gl. Maximus) and knees (Quadriceps Femoris-QF), the Hand-Held Dynamometer (HHD) was used. Results. A significant difference was observed in the muscle strength of Gl. medius in TPP patients and of Gl. maksimus in conventional TKP patients (p <0.05). Compared to the healthy group, only hip muscle strength decreased in TPP patients, but both hip and knee muscle strengths decreased in conventional TKP patients (p <0.05). Conclusion. A decrease in hip and knee muscle strengths was determined in the TPP and conventional THA patients, compared to healthy subjects. Compared to the bone protective prosthetic systems (eg TPP), a significant difference is observed in the QF muscle strength in intramedullary prosthesis applications. This data may be used in planning the treatment of patients with hip arthroplasty

Current modeling techniques have been used to model the Reverse Total Shoulder Arthroplasty (RTSA) to account for the geometric changes implemented after RTSA. Though these models have provided insight into the effects of geometric changes from RTSA these is still a limitation of understanding muscle function after RTSA on a patient-specific basis. The goal of this study sought to overcome this limitation by developing an approach to calibrate patient-specific muscle strength for an RTSA subject. The approach was performed for both isometric 0° abduction and dynamic abduction. A 12 degree of freedom (DOF) model developed in our previous work was used in conjunction with our clinical data to create a set of patient-specific data (3 dimensional kinematics, muscle activations, muscle moment arms, joint moments, muscle length, muscle velocity, tendon slack length, optimal fiber length, peak isometric force)) that was used in a novel optimization scheme to estimate muscle parameters that correspond to the patient's muscle strength[4]. The optimization varied to minimize the difference between measured(“in vivo”) and predicted joint moments and measured (“in vivo”) and predicted muscle activations. The predicted joint moments were constructed as a summation of muscle moments. The nested optimization was implemented within matlab (Mathworks). The optimization yields a set of muscle parameters that correspond to the subject's muscle strength. The abduction activity was optimized. The maximum activation for the muscles within the model ranged between .03–2.4 (Figure 1). The maximum joint moment produced was 11 newton-meters. The joint moments were reproduced to an value of 1. Muscle parameters were calculated for both isometric and dynamic abduction (Figure 2). The muscle parameters produced provided a feasible solution to reproduce the joint moments seen “in vivo” (Figure 3). Current modeling techniques of the upper extremity focus primarily on geometry. In efforts to create patient-specific models we have developed a framework to predict subject-specific strength characteristics. In order to fully understand muscle function we need muscle parameters that correspond to the subject's strength. This effort in conjunction with patient-specific models that incorporate the patient's joint configurations, kinematics and bone anatomy hopes to provide a framework to gain insight into muscle tensioning effects after RTSA. With this framework improvements can be made to the surgical implementation and design of RTSA to improve surgical outcomes

Introduction. Current modeling techniques have been used to model the Reverse Total Shoulder Arthroplasty (RTSA) to account for the geometric changes implemented after RTSA [2,3]. Though these models have provided insight into the effects of geometric changes from RTSA these is still a limitation of understanding muscle function after RTSA on a patient-specific basis. The goal of this study sought to overcome this limitation by developing an approach to calibrate patient-specific muscle strength for an RTSA subject. Methods. The approach was performed for both isometric 0° abduction and dynamic abduction. A 12 degree of freedom (DOF) model developed in our previous work was used in conjunction with our clinical data to create a set of patient-specific data (3 dimensional kinematics, muscle activations (), muscle moment arms, joint moments, muscle length, muscle velocity, tendon slack length (), optimal fiber length, peak isometric force)) that was used in a novel optimization scheme to estimate muscle parameters that correspond to the patient's muscle strength[4]. The optimization varied to minimize the difference between measured (“in vivo”) and predicted joint moments and measured (“in vivo”) and predicted muscle activations (). The predicted joint moments were constructed as a summation of muscle moments. The nested optimization was implemented within matlab (Mathworks). The optimization yields a set of muscle parameters that correspond to the subject's muscle strength. The abduction activity was optimized [4,5]. To validate the model we predicted dynamic joint moment and activation for the abduction activity (Figure 1). Results. The muscle activation for the lateral deltoid had a normalized correlation of value of .91(Figure 1 left). The maximum joint moment produced was 18 newton-meters. The joint moments were reproduced to an value of 1 (Figure 1 Right). Muscle parameters were calculated for both isometric and dynamic abduction. The muscle parameters produced provided a feasible solution to reproduce the muscle activation and joint moments seen “in vivo” (Figure 1). Discussion. Current modeling techniques of the upper extremity focus primarily on geometric changes and their effects on shoulder muscle moment arms. In efforts to create patient-specific models we have developed a framework to predict subject-specific strength characteristics. In order to fully understand muscle function we need muscle parameters that correspond to the subject's strength. This effort in conjunction with patient-specific models that incorporate the patient's joint configurations, kinematics and bone anatomy provide a framework to gain insight into muscle tensioning effects after RTSA. This framework describes the relationship between muscle lengthening and muscle performance (recruitment and force generation). With this framework improvements can be made to the surgical implementation and design of RTSA to improve surgical outcomes. Significance. This abstract is the first of its kind to use patient-specific fluoroscopy kinematics, muscle activation and joint moments to create a framework to predict a patients muscle function (activation, force) for RTSA groups. This now allows us to understand how differences in implant design and surgical technique affect each muscle's ability to generate force and function. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Purpose. Stress fractures (SFs) are highly prevalent in female athletes, especially runners (1337%), and result in pain and lost training time. There are numerous risk factors for SFs in athletes; however, the role of bone quality in the etiology of SFs is currently unknown. Therefore, our primary objective was to examine whether there are characteristic differences in bone quality and bone strength in female athletes with lower limb SFs using high-resolution peripheral quantitative computed tomography (HR-pQCT). A secondary objective was to compare muscle strength between SF subjects and controls. Method. Female athletes with (n=19) and without (n=19) lower limb SFs were recruited from the local community. All SFs were medically confirmed by a physician and subjects were assessed within 1–47 weeks (12.7 13.7) of diagnosis. Controls were age-, training volume- and sport-matched to SF athletes. Bone density and microarchitectural bone parameters such as cortical thickness and porosity, as well as trabecular thickness, separation and number of all subjects were assessed using HR-pQCT at two distal tibia scanning sites (distal, ultra-distal). Finite element (FE) analysis was employed to estimate bone strength and load sharing of cortical and trabecular bone from the HR-pQCT scans. Regional analysis was applied to the HR-pQCT scans to investigate site-specific bone differences between groups. Muscle torque was measured by a Biodex dynamometer as a surrogate of muscle strength. Independent sample t-tests and Mann-Whitney U-tests were used for statistical analyses (p < 0.05). Results. Significant differences and trends indicated compromised trabecular bone and slightly thicker cortices with fewer pores in SF subjects compared with controls. This was most pronounced in the posterior region of the distal tibia, which is the site of highest tensile stresses during running and a common SF site. FE analysis indicated significantly higher cortical loads (median 4.2% higher; p=0.03) in the distal tibia site (but not ultra-distal site) of SF subjects compared to controls. The SF group exhibited significantly reduced knee extension strength (median 18.3% lower; p=0.03) and a trend towards reduced plantarflexion (median 17.3% lower; p=0.24) and eversion strength (median 9.6% lower; p=0.49) compared to controls. Conclusion. This is the first study to compare bone microarchitectural quality and lower-limb muscle strength between female athletes with SFs and health controls. A reduced trabecular bone quality in SF subjects may result in an insufficient ability to absorb and distribute tibial loads. This, in turn, may lead to higher stresses in the cortex and a higher risk for SFs. Low muscle strength may increase SF risk by providing insufficient muscular support to counteract shear stresses associated with reaction forces during running. Further study is needed to determine whether a resistance-training program can improve bone quality and in turn, reduce SF risk

Modern musculoskeletal modeling techniques have been used to simulate shoulders with reverse total shoulder arthroplasty and study how geometric changes resulting from implant placement affect shoulder muscle moment arms. These studies do not, however, take into account how changes in muscle length will affect the force generating capacity of muscles in their post-operative state. The goal of this study was to develop and calibrate a patient-specific shoulder model for subjects with RTSA in order to predict muscle activation during dynamic activities. Patient-specific muscle parameters were estimated using a nested optimization scheme calibrating the model to isometric arm abduction data at 0°, 45° and 90°. The model was validated by comparing predicted muscle activation for dynamic abduction to experimental electromyography recordings. A twelve-degree of freedom model was used with experimental measurements to create a set of patient-specific data (three-dimensional kinematics, muscle activations, muscle moment arms, joint moments, muscle lengths, muscle velocities, tendon slack lengths, optimal fiber lengths and peak isometric forces) estimating muscle parameters corresponding to each patient's measured strength. The optimization varied muscle parameters to minimize the difference between measured and estimated joint moments and muscle activations for isometric abduction trials. This optimization yields a set of patient-specific muscle parameters corresponding to the subject's own muscle strength that can be used to predict muscle activation and muscle lengths for a range of dynamic activities. The model calibration/optimization procedure was performed on arm abduction data for a subject with reverse total shoulder arthroplasty. Muscle activation predicted by the model ranged between 3% and 90% of maximum. The maximum joint moment produced was 20 Nm. The model replicated measured joint moments accurately (R2 > 0.99). The optimized muscle parameter set produced feasible muscle moments and muscle activations for dynamic arm abduction, when calibrated using data from isometric force trials. Current modeling techniques for the upper extremity focus primarily on geometric changes and their effects on shoulder muscle moment arms. In an effort to create patient-specific models, we have developed a framework to predict subject-specific muscle parameters. These estimated muscle parameters, in combination with patient-specific models that incorporate the patient's joint configurations, kinematics and bone anatomy, provide a framework to predict dynamic muscle activation in novel tasks and, for example, predict how joint center changes with reverse total shoulder arthroplasty may affect muscle function

Introduction. Although Total elbow arthroplasty (TEA) generally provides favorable clinical outcomes, its complications have been reported with high rate compared with other joints. Previously, we used the Bryan & Morrey approach in TEA, which included separating the triceps muscle subperiosteally from the olecranon; however, since 2008, in order to prevent skin trouble and deficiency of the triceps, we performed TEA by MISTEA method, which required no removal of the subcutaneous tissue in the region of the olecranon and no release or stripping of the triceps tendon. Objectives. The purpose of this study was to examine the utility of the MISTEA method by evaluating and comparing muscle strength and complications by using both the Bryan & Morrey approach and MISTEA method. Materials and Methods. The study was conducted on 23 elbows, on which elbow muscle strength could be measured postoperatively at more than 6 months after TEA. Thirteen elbows were operated on the Bryan & Morrey approach (BM group; mean age, 62.3 years; mean follow-up period, 27 months), and 10 elbows on the MISTEA method (MIS group; mean age, 67.6 years; mean follow-up period, 19.1 months). To determine the elbow extensor and flexor strengths, measurements were conducted on the affected side for the BM group, and on both the affected and healthy sides for the MIS group. Further, the “extension/flexion ratio” as well as the “affected/healthy side ratio” and complications were assessed. Results. Excluding the elbow extensor strength of 3 elbows in the BM group, which could not be measured too week. The extension/flexion ratio was as follows: in the BM group, 0.61 and in the MIS group, 0.93 on the affected side and 0.81 on the healthy side. For the MIS group, in which measurements could be performed on both the sides, the “affected/healthy side ratio” was 0.72 in flexion and 0.91 in extension. In terms of complications, skin trouble was found on 2 elbows in the BM group and on 1 elbow in the MIS group; further, rupture of the triceps tendon was suspected in 3 elbows in the BM group but was not found in the MIS group. Discussion. In our study, deficiency in triceps muscle was found in 3 of 13 elbows with the Bryan & Morrey approach. MISTEA method may be the reason for prevention of deficiency or rupture of the triceps tendon. The MIS group had higher extension/flexion ratio in the affected side, suggesting the possibility that either the extensor strength had increased or the flexor strength had weakened. Further, in the MIS group, the extension showed an “affected/healthy side” ratio, which means that an extensor strength almost equivalent to that of the healthy side was maintained, whereas the flexor strength was 72% of that on the healthy side, suggesting that the flexor strength may have decreased. Loss of the flexor strength may be because the MISTEA method involves partial release of the brachialis muscle and the joint's center of rotation to move slightly towards the proximal side

Total joint replacement (TJR) is by far the most effective therapy for end-stage OA patients. Most of patients achieve joint pain reduction and function improvement following to TJR, however up to 22% of them either do not improve or deteriorate after surgery. The aim of this study was to identify genetic variants to be associated with poor outcome of TJR in primary OA patients by a genome-wide association approach (GWAS). Study participants were primary OA patients from the Newfoundland Osteoarthritis Study (NFOAS) that comprised total knee or hip replacement and recruited before 2016 in St. John's, NL. DNA samples were extracted from patients' blood. Study participants completed their pre-operation and 3.99±1.38 years post-surgery outcome assessment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). DNA samples were genotyped using the genome-wide Illumina HumanOmni2.58 genotyping microarray containing 2.4 million SNPs. Pre-association quality control filtering was conducted for the raw genotyping data using PLINK 1.7 program, and genotype imputation was performed using the IMPUTE2 algorithm with multiple population reference data from 1000 Genome Project. The imputed data with ∼3.1 million variants was used to test the association with non-responders to TJR using the additive genetic model. Eighty three primary OA patients (44 responders and 39 non-responders) were included in the analysis. Association analysis detected three chromosomal regions on chr5, 7, and 8 to be significantly associated with non-responding to pain. The top SNPs at these loci are intergenic variants that include SNP (rs17118094, p=4.4×10-5) on chr5. This SNP is adjacent to SGCD gene that plays an important role in muscular strength and maintenance. Another associated SNP (rs71572810, p=4.7×10-5) is nearby IMMP2L gene on chr7. This gene is reported to be associated with behavioral abnormalities. Finally, SNP (rs6992938, p=5.8×10-5) on chr8 is located downstream of TRPA1 gene that is known to have a central role in the pain response to endogenous inflammatory mediators. Three loci were also found to be significantly associated with non-responding to function. The lead variant in the locus on chr1 is an intergenic SNP (rs9729377, p=1.7×10-5) falling between CTBS and MCOLN2 genes. CTBS gene is associated with TNF-α, a cytokine that stimulate the inflammation acute phase reaction, and MCOLN2 gene plays a role in the chemokine secretion and macrophage migration in the innate immune response. Other top SNPs in loci on chr2 and 10 harbor CCDC93, INSIG2, and KLF6 genes that are associated with heel bone mineral density, hypercholesterolemia, obesity and BMI. To our knowledge, this project is the first study that investigated the association between genetic factors and TJR non-responders. Our results demonstrated that genes related to muscle strength, behavioral trait, pain response, and inflammation play a significant role in poor outcome of TJR, warranting further investigation

Musculoskeletal modeling techniques simulate reverse total shoulder arthroplasty (RTSA) shoulders and how implant placement affects muscle moment arms. Yet, studies have not taken into account how muscle-length changes affect force-generating capacity postoperatively. We develop a patient-specific model for RTSA patients to predict muscle activation.

Patient-specific muscle parameters were estimated using an optimization scheme calibrating the model to isometric arm abduction data at 0°, 45°, and 90°. We compared predicted muscle activation to experimental electromyography recordings. A twelve-degree of freedom model with experimental measurements created patient-specific data estimating muscle parameters corresponding to strength. Optimization minimized the difference between measured and estimated joint moments and muscle activations, yielding parameters corresponding to subjects' strength that can predict muscle activation and lengths.

Model calibration was performed on RTSA patients' arm abduction data. Predicted muscle activation ranged between 3% and 70% of maximum. The maximum joint moment produced was 10 Nm. The model replicated measured moments accurately (R² > 0.99). The optimized muscle parameters produced feasible muscle moments and activations for dynamic arm abduction when using data from isometric force trials. A normalized correlation was found between predicted and experimental muscle activation for dynamic abduction (r > 0.9); the moment generation to lift the arm was tracked (R² = 0.99).

Statement of Clinical Significance: We developed a framework to predict patient-specific muscle parameters. Combined with patient-specific models incorporating joint configurations, kinematics, and bone anatomy, they can predict muscle activation in novel tasks and, e.g., predict how RTSA implant and surgical decisions may affect muscle function.

Abstract. Background. Multi-ligament knee injury is a rare but severe injury. Treatment strategies are challenging for most orthopedic surgeons & optimal treatment remains controversial. The purpose of our study was to assess clinico-radiological and functional outcomes after surgical management of multi-ligament knee injuries & to determine factors that could predict outcome of surgery. Materials And Method. It is a prospective observational study of 30 consecutive patients of Multi-ligament knee injury conducted between 2018–2020. All patients were treated surgically with single-stage reconstruction of all injured ligaments and followed standardized postoperative rehabilitation protocol. All patients were evaluated for Clinical (VAS score, laxity stress test, muscle-strength, range of motion), Radiological (stress radiographs) & Functional (Lysholm score) outcomes three times-preoperatively, post-operative 3 & 12 months. Results. At final follow up mean VAS score was 0.86±0.77. The anteroposterior & valgus-varus stress test showed ligament laxity >10mm (GradeD) in 93.3% patient which improved to <3mm (normal, GradeA) in 90% patients. Most patients (83.3%) had preoperative-range <100° and muscle strength of MRC Grade-3 which improved to >120° and muscle strength of MRC grade-5 at final followup. Lysholm score was poor (<64) in all patients preoperatively and improved to good (85–94) in 73.3%, excellent (>95) in 20% & fair (65–84) in 6.6% patients. The stress radiographs showed stable results for anterior/posterior & varus/valgus stress. All patients returned to their previous work. Factors that could predict outcomes of surgery are age, timing of surgery, type of surgery & associated injury. Conclusion. Early complete single stage reconstruction can achieve good functional results with overall restoration of sports & working capacity. Positive predictive factors for good outcome are younger age, early surgery & appropriate rehabilitation

As the field of hip arthroscopy continues to develop, functional measures and testing become increasingly important in patient selection, managing patient expectations prior to surgery, and physical readiness for return to athletic participation. The Hip Sport Test (HST) was developed to assess strength, coordination, agility, and range of motion prior to and following hip arthroscopy as a functional assessment. However, the relationship between HST and hip strength, range of motion, and hip-specific patient reported outcome (PRO) measures have not been investigated. The purpose of this study was to evaluate the correlation between the HST scores and measurements of hip strength and range of motion prior to undergoing hip arthroscopy. Between September 2009 and January 2017, patients aged 18-40 who underwent primary hip arthroscopy for the treatment of femoroacetabular impingement with available pre-operative HST, dynamometry, range of motion, and functional scores (mHHS, WOMAC, HOS-SSS) were identified. Patients were excluded if they were 40 years old, had a Tegner activity score < 7, or did not have HST and dynamometry evaluations within one week of each other. Muscle strength scores were compared between affected and unaffected side to establish a percent difference with a positive score indicating a weaker affected limb and a negative score indicating a stronger affected limb. Correlations were made between HST and strength testing, range of motion, and PROs. A total of 350 patients met inclusion criteria. The average age was 26.9 ± 6.5 years, with 34% females and 36% professional athletes. Total and component HST scores were significantly associated with measure of strength most strongly for flexion (rs = −0.20, p < 0 .001), extension (rs = −0.24, p<.001) and external rotation (rs = −0.20, p < 0 .001). Lateral and diagonal agility, components of HST, were also significantly associated with muscle strength imbalances between internal rotation versus external rotation (rs = −0.18, p=0.01) and flexion versus extension (rs = 0.12, p=0.03). In terms of range of motion, a significant correlation was detected between HST and internal rotation (rs = −0.19, p < 0 .001). Both the total and component HST scores were positively correlated with pre-operative mHHS, WOMAC, and HOS-SSS (p<.001 for all rs). The Hip Sport Test correlates with strength, range of motion, and PROs in the preoperative setting of hip arthroscopy. This test alone and in combination with other diagnostic examinations can provide valuable information about initial hip function and patient prognosis

Introduction. Most of patients with unilateral hip disease shows muscle volume atrophy of pelvis and thigh in the affected side because of pain and disuse, resulting in reduced muscle weakness and limping. However, it is unclear how the muscle atrophy correlated with muscle strength in the patient with hip disorders. A previous study have demonstrated that the volume of the gluteus medius correlated with the muscle strength by volumetric measurement using 3 dimensional computed tomography (3D-CT) data, however, muscles influence each other during motions and there is no reports focusing on the relationship between some major muscles of pelvis and thigh including gluteus maximus, gluteus medius, iliopsoas and quadriceps and muscle strength in several hip and knee motions. Therefore, the purpose of the present study is to evaluate the relationship between muscle volumetric atrophy of major muscles of pelvis and thigh and muscle strength in flexion, extension and abduction of hip joints and extension of knee joint before surgery in patients with unilateral hip disease. Material and Methods. The subjects were 38 patients with unilateral hip osteoarthritis, who underwent hip joint surgery. They all underwent preoperative computed tomography (CT) for preoperative planning. There were 6 males and 32 females with average age 59.5 years old. Before surgery, isometric muscle strength in hip flexion, hip extension, hip abduction and knee extension were measured using a hand held dynamometer (µTas F-1, ANIMA Japan). Major muscles including gluteus maximus, gluteus medius, iliopsoas and quadriceps were automatically extracted from the preoperative CT using convolutional neural networks (CNN) and were corrected manually by the experienced surgeon. The muscle volumetric atrophy ratio was defined as the ratio of muscle volume of the affected side to that of the unaffected side. The muscle weakness ratio was defined as the ratio of muscle strength of the affected side to that of the unaffected side. The correlation coefficient between the muscle atrophy ratio and the muscle weakness ratio of each muscle were calculated. Results. The average muscle atrophy ratio was 84.5% (63.5%–108.2%) in gluteus maximus, 86.6% (65.5%–112.1%) in gluteus medius, 81.0% (22.1%–130.8%) in psoas major, and 91.0% (63.8%–127.0%) in quadriceps. The average muscle strength ratio was 71.5% (0%–137.5%) in hip flexion, 88.1% (18.8%–169.6%) in hip abduction, 78.6% (21.9%–130.1%) in hip extension and 84.3% (13.1%–122.8%) in knee extension. The correlation coefficient between the muscle atrophy and the ratio of each muscle strength between the affected and unaffected side were shown in Table 1. Conclusion. In conclusion, the muscle atrophy of gluteus medius muscle, psoas major muscle and quadriceps muscle significantly correlated with the muscle weakness in hip flexion. The muscle atrophy of psoas major muscle and quadriceps muscle also significantly correlated with the muscle weakness in knee extension. There were no significant correlation between the muscle atrophy and the muscle weakness in hip extension and abduction

The progressive painful and disabling predicament of patients with severe osteoarthritis awaiting a total hip or knee arthroplasty (THA/TKA) results in a decline in muscle mass, strength and function also known as Sarcopenia. We conducted a cross-sectional, prospective study of patients on the waiting-list for a THA/TKA in the South Australian public healthcare system and compared the findings to healthy participants and patients newly referred from their general practitioners. Participants with a history of joint replacements, pacemakers and cancers were excluded from this study. Outcomes of this study included (i) sarcopenia screening (SARC-F ≥4); (ii) sarcopenia, defined as low muscle strength (hand grip strength M<27kg; F<16kg), low muscle quality (skeletal muscle index M<27%, F<22.1%) and low physical performance (short physical performance battery ≤8). Additional outcomes include descriptions of the recruitment feasibility, randomisation and suitability of the assessment tools. 29 healthy controls were recruited; following screening, 83% (24/29) met the inclusion criteria and 75% (18/24) were assessed. 42 newly referred patients were recruited; following screening, 67% (30/45) met the inclusion criteria and 63% (19/30) were assessed. 68 waiting list patients were recruited; following recruitment, 24% (16/68) met the inclusion criteria and 75% (12/16) were assessed. Preliminary data shows increasing waiting time is associated with higher SARC-F scores, lower hand grip strength and lower muscle quality. As a pilot study, preliminary data demonstrate that: (1) study subjects’ willingness to participate will enable a larger study to be conducted to establish the prevalence of sarcopenia and the diagnostic cut-off points for this patient group. (2) SARC-F is a suitable tool to screen for sarcopenia. (3) There is a positive correlation between waiting time for a THA/TKA and sarcopenia

Pain immediately following total knee arthroplasty (TKA) is often severe and can inhibit patients' rehabilitation. Recently, adductor canal blocks have been shown to provide adequate analgesia and spare quadriceps muscle strength in the early postoperative period. We devised a single injection motor sparing knee block (MSB) by targeting the adductor canal and lateral femoral cutaneous nerve with a posterior knee infiltration under ultrasound. Our primary objective was to evaluate the analgesia duration of the MSB in comparison to a standard periarticular infiltration (PAI) analgesia using patients' first rescue analgesia as the end point. Secondary outcomes measured were quadriceps muscle strength and length of stay. We randomised 82 patients scheduled for elective TKA to receive either the preoperative MSB (0.5% ropivacaine, 2.5ug/ml epinephrine, 10mg morphine, and 30mg ketorolac) or intraoperative periarticular infiltration (0.3% ropivacaine, 2.5ug/ml epinephrine, 10mg morphine, and 30mg ketorolac). Duration of analgesia, postoperative quadriceps power, and length of stay were evaluated postoperatively. Analgesic duration was found to be significantly different between groups. The MSB had a mean duration of 18.06 ± 1.68 hours while the PAI group had a mean duration of 9.25 ± 1.68 hours for a mean difference of 8.8 hours (95% CI 3.98 to 13.62), p<0.01. There were no significant differences between groups in quadriceps muscle strength power at 20 minutes (p=0.91) or 6 hours (p=0.66) after block administration. Length of stay was also not significantly different between the groups (p=0.29). Motor sparing blocks provide longer analgesia than patients receiving periarticular infiltration while not significantly reducing quadriceps muscle strength or increasing length of hospital stay

There are some reports that the invasive surgery of knee joint replacement repair static and dynamic balance. We investigated the changes in static and dynamic balance and muscle strength in pre- and postoperative of TKA and UKA for the purpose of assessing time dependent improvement. A total of 168 patients (137 TKA; mean age 75.3, 31 UKA; mean age 78.1) were recruited to the study. These patients underwent static and dynamic balance assessment and muscle strength pre operation and 3, 6, 12 months post operation. The parameters of assessment were one leg standing time (open or close eyes), postural sway test (open or close eyes), 3m timed-up-and-go test, maximum stride and Isokinetic muscle strength. We have evaluated both the absolute value and the index which divided the value of the post-operation with the value of pre-operation. Alignment had improved significantly after surgery in TKA and UKA. Isokinetic muscle strength (Fig. 1), one leg standing time with open eyes, 3m timed-up-and-go test (Fig. 2) and maximum stride showed better improvement than pre operation at 3, 6, and 12 months after surgery in TKA and UKA. On the other hand, one leg standing time with close eyes and postural sway test showed no improvement than pre operation at any time after operation (Fig. 3). Butpostural sway test in UKA showed the improvement trend at 3 months after surgery. In contrast, those test in TKA showed no improvement at 3 months after surgery (Fig. 3). Our result showed the improvement of balance function correlated with muscle recovery and improvement of lower limb alignment than equilibrium function after the artificial knee joint replacement surgery. Because one leg standing time with close eyes and one leg postural sway test represent the equilibrium function than other tests. It is interesting that significant difference in the recovery of postural sway in three months after surgery in UKA compared with TKA

This prospective, longitudinal study documents the muscle strength and baseline function of 18 patients undergoing closed femoral shortening for discrepancy in limb length. Patients were studied for two years following surgery. Function was measured by a self-reported questionnaire, timed tests of performance and measurements of muscle strength and power. After two years, the self-reported function and ability to complete timed functional tests had returned to or improved on the pre-operative values. Muscle strength remained slightly below the pre-operative value and was more marked in the quadriceps than the hamstrings. This study suggests that small decreases in muscle strength and power following closed femoral shortening do not adversely affect the patients’ ability to perform everyday activities

Introduction. A total knee replacement is a proven cost-effective treatment for end-stage osteoarthritis, with a positive effect on pain and function. However, only 80% of the patients are satisfied after surgery. It is known that high preoperative expectations and residual postoperative pain are important determinants of satisfaction, but also malalignment, poor function and disturbed kinematics can be a cause. The purpose of this study was to investigate the correlation between the preoperative function and the postoperative patient reported outcomes PROMs) as well as the influence of the postoperative functional rehabilitation on the PROMs. Methods. 57 patients (mean 62,9j ± 10,6j), who suffer from knee osteoarthritis and who were scheduled for a total knee replacement at our centre, participated in this study. The range of motion of the knee, the muscle strength of the M. Quadriceps and the M. Hamstrings and the functional parameters (‘stair climbing test’ (SCT), ‘Sit to stand’ (STS) and ‘6 minutes walking test’ (6MWT)) were measured the night before surgery, ±6 months and ±1 year after surgery. This happened respectively with the use of a goniometer, HHD 2, stopwatch and the ‘DynaPort Hybrid’. Correlations between pre- and postoperative values were investigated. Secondly, a prediction was made about the influence of the preoperative parameters on on the subjective questionnaires (KOOS, OXFORD and KSS) as well as a linear and logistic regression. Results. 6 Months after surgery, an improvement of all parameters for ROM, muscle strength and functional status was found. With a significant difference for the active and passive ROM toward knee flexion (p=0.007;p=0.008), asymmetry in active and passive ROM toward flexion between the healthy leg and the leg with the TKA (p=0.001;p=0.001), Quadriceps- and Hamstrings strength (p=0.001;p<0.001), time of the STS test (p=0.012), time sit-stand (p=0.002), time stand-sit (p=0.001;p<0.001), all parameters for the 6MWT and the time of the SCT (p=0.001). Regarding the prediction model, the 6month PROMs can be predicted by some parameters for the 6MWT (distance (p=0.001), gait steps (p=0.002) and step time TKA (p=0.007)). These parameters are predictors for the score on the subscales ‘symptoms’ and ‘pain’ of the KOOS questionnaire. 1 Year after surgery, there is an improvement of all parameters, except for the active and passive ROM toward knee extension. However, these differences are not significant. The 1 year PROMs can only be predicted by the muscle strength (Quadriceps- and Hamstrings strength (p=0.026; p=0.039) and the asymmetry in Quadriceps strength between the healthy leg and the leg with the TKA (p=0.031)). The score on the subscale ‘pain’ can be predicted based on the parameters mentioned above. Conclusion. Patient satisfaction after TKA is a multivariate model. Regarding the functional outcome, we could find that there is a correlation between the muscle force, walking distance and the PROMs. More research is currently being done to create a better prediction model and investigate the correlations more thoroughly

INTRODUCTION. Cadaveric studies have reported damage to the direct head of rectus femoris and tensor fascia lata muscles with direct anterior approach(DAA) and to the abductors, external rotators with posterior approach(PA). The aim of this prospective study was to evaluate differences in hip muscle strength recovery between DAA and posterior approach (PA) THA. METHODS. Patients with unilateral hip osteoarthritis undergoing THA at a single institution from January 2011 to October 2011 were enrolled. All DAA THA's were performed by one surgeon, and all PA THA's were performed by another surgeon with similar design of components, pain management and rehabilitation protocols. Hip muscle strength was measured with a handheld dynamometer in all planes by a single observer preoperatively, at 6 weeks, 3 months and 6 months. Functional recovery was assessed with the motor component of Functional Independence Measure, UCLA activity score, Harris hip score, SF-12 score. RESULTS. There were 30 patients (15 per group) with similar age, sex, BMI and preoperative functional scores. There was a significant difference between groups in ER strength recovery pattern(p=0.04) with greater mean deficit in PA group from preoperative to 6 weeks(37%), 3 months (28%) and 6 months (25%); whereas DAA group demonstrated 3% mean deficit at 6 weeks, 2% mean improvement at 3 months and 10% mean improvement at 6 months from preoperative values. Flexion strength decreased in DAA group by a mean of 10% at 6 weeks(p=0.07) but improved at 3 months by a mean of 12% as compared to preoperative values. There were no differences in recovery pattern of other hip movements between groups. Functional recovery scores between groups were similar. DISCUSSION. Both DAA and PA THA offer similar recovery in hip muscle strength up to 6 months with exceptions of ER strength deficit in PA group and a trend to flexion strength deficit at 6 weeks in DAA group

Purpose. Change of the pelvic tilt is an important factor affecting walking after total hip arthroplasty (THA). There are many reports of static evaluation of pelvic tilt by X-ray, however, there are few reports of dynamic evaluation during walking. In this study, we investigated change of pelvic tilt of THA subjects before and after operation during walking using an optical position sensor. Subjects and Methods. 5 normal volunteers (mean age 26.6 years old, Control group) and 10 patients who underwent primary THA due to unilateral osteoarthritis of the hip (mean age 61 years old, THA group) were enrolled. We have measured angle of the hip and inclination of the pelvis in the mid-stance phase of the affected limb during walking using a motion analyzer (MAC3D system) and acquired physical assessment of the hip preoperatively, 3 weeks postoperatively and 3 months postoperatively. The acquired data of inclination of the pelvis was classified as Duchenne or Trendelenburg type compared with that of normal volunteers. Result. Trendelenburg type in 6 patients and Duchenne type in 4 patients were found preoperatively with THA group. Trendelenburg type showed abductor muscle weakness and limited range of motion (ROM) in hip abduction, and Duchenne type showed a limited ROM in hip adduction with physical examination. At 3 weeks after surgery, 9 of 10 THA patients resulted in the Duchenne type. At 3 months after surgery, the inclination angle of the pelvis showed the same as that of healthy subjects in 5 of the 9 patients, in which hip abduction ROM increased and abductor muscle strength recovered among Trendelenburg type and hip adduction ROM increased among Duchenne type (Figure 1). The pelvic inclination returned to preoperative state in 4 patients, in which limitation of hip abduction ROM and abductor muscle weakness remained in Trendelenburg type preoperatively and limitation of hip adduction ROM remained in Duchenne type preoperatively (Figure 2). Discussion. As a risk factor for limping after THA, preoperative limitation of ROM in hip abduction or adduction can be related, leading to necessity of systematical estimation for ROM of the hip with physical assessment and pelvic tilt type in the mid-stance during walking prior to surgery. In addition, preoperative maximum hip adduction angle and abduction muscle strength can be affected to change of the pelvic tilt after THA. It is important to recover of these ROM and muscle strength with physical therapy for prevention of postoperative limping

Introduction. Upright body posture is maintained with the alignment of the spine, pelvis, and lower extremities, and the muscle strength of the body trunk and lower extremities. Conversely, the posture is known to undergo changes with age, and muscle weakness of lower extremities and the restriction of knee extension in osteoarthritis of the knee (knee OA) have been considered to be associated with loss of natural lumbar lordosis and abnormal posture. As total knee arthroplasty (TKA) is aimed to correct malalignment of lower extremities and limited range of motion of knee, particularly in extension, we hypothesized that TKA positively affects the preoperative abnormal posture. To clarify this, the variation in the alignment of the spine, pelvis, and lower extremities before and after TKA was evaluated in this study. Patients and methods. Patients suffering from primary knee OA who were scheduled to receive primary TKA were enrolled in this study. However, patients with arthritis secondary to another etiology, i.e. rheumatoid arthritis, trauma, or previous surgical interventions to the knee, were excluded. Moreover, patients who suffered from hip and ankle OA, cranial nerve diseases, or severe spinal deformity were also excluded. The sagittal vertical axis (SVA), the horizontal distance between the posterosuperior aspect of the S1 endplate surface and a vertical plumb line drawn from the center of the C7 vertebral body, is an important index of sagittal balance of the trunk. Thus, patients were classified into two groups based on the preoperative SVA with preoperative standing lateral digital radiographs: normal (< 40mm) and abnormal (≥ 40mm) groups. The variations in the sagittal alignment of the spine, pelvis and lower extremities were evaluated preoperatively, and at 1 and 3 months postoperatively. This study was approved by an institutional review board, and informed consent for participation was obtained from the patients. Results. Forty-nine knees in 49 patients were enrolled. Three different patterns of postural changes as well as hip and knee angles following TKA were observed. After TKA, the preoperatively normal SVA patients (26.5%) showed extension of the hip and knee joints and decrease of lumbar lordosis, while the SVA remained almost within the normal range. In the preoperatively abnormal SVA group, 13 patients (26.5%) showed extension of the knee joint while the SVA remained abnormal, however, 23 of the preoperatively abnormal SVA group patients (47.0%) showed improvement of SVA into the normal range with the extension of the hip and knee joints. Discussion. As the spine, pelvis, and lower extremities together affect body alignment, once limitation of knee extension due to severe knee OA is corrected and lower extremity alignment is improved with TKA, the lumbar lordosis may increase, and SVA could decrease. Recently, the relationship between the imbalance of the sagittal plane of the body and the risk of falls was described. From this, it could be said that TKA not only helped in recovering knee function and lower extremity alignment in severe knee OA, but also helped to improve posture and to protect from falls