Effects of Teriparatide in Patients with Osteoporosis in Clinical Practice: 42-Month Results During and After Discontinuation of Treatment from the European Extended Forsteo® Observational Study (ExFOS).

This study aimed to describe clinical outcomes in patients prescribed teriparatide and followed up for 18 months after stopping the drug in real-life conditions. The Extended Forsteo® Observational Study analysed incident clinical fractures in 6-month intervals using logistic regression with repeated measures. Changes in back pain (visual analogue scale) and health-related quality of life (HRQoL; EQ-5D questionnaire) were analysed using mixed models for repeated measures. Patients were analysed if they had a post-baseline visit, regardless of whether and for how long they took teriparatide. Of 1531 patients analysed (90.7% female, mean age: 70.3 years), 76 (5.0%) never took teriparatide. Median treatment duration was 23.6 months. The adjusted odds of clinical fracture decreased by 47% in the > 12- to 18-month treatment period (p = 0.013) compared with the first 6-month period, with no statistically significant reduction in the > 18- to 24-month interval. The clinical fracture rate remained stable during the 18 months' post-teriparatide, when approximately 98% of patients took osteoporosis medication (51% bisphosphonates). Clinical vertebral fractures were reduced at every time period compared with the first 6 months. Adjusted mean back pain scores decreased and EQ-5D scores increased significantly at each post-baseline observation. In a real-life clinical setting, the risk of clinical fractures declined during 24 months of teriparatide treatment. This reduction was maintained 18 months after stopping teriparatide. In parallel, patients reported significant improvements in back pain and HRQoL. The results should be interpreted in the context of the non-controlled design of this observational study.

The effect of a new oral anticoagulant (Rivaroxaban) on implants pull-out strength. An experimental study in rats.

OBJECTIVES: Thromboprophylaxis reduces the risk of surgery related deep venous thrombosis and pulmonary embolism. The classical anticoagulants (heparin and LWMH) were associated with systemic osteoporosis, poor bone healing and materials' osseointegration. There is a lack of data concerning the effect of the new orally administered anticoagulants on osseointegration. The aim of this study is to investigate the possible effect of rivaroxaban, a direct anti-Xa factor, on osseointegration. METHODS: Twenty eight white, male, Wistar rats were divided into two groups: Group A, study group (n=14) and group B, control group (n=14). In all animals under general anesthesia one screw was inserted on the right tibia. For twenty eight days the animals of group A received intraperitoneal rivaroxaban injections 5mgr/kgr every day. The animals of group B received intraperitoneal equal amount of normal saline injections. At the end of the four weeks all animals were sacrificed and their right tibias were excised and underwent the pull-out test. RESULTS: The mean values of pull-out test were 92,10±19,12N for the control group and 95,46±21,02N for the study group. The statistical analysis using t-test showed no significant difference (p=0,665) for the pull-out test. CONCLUSIONS: These results indicate that Rivaroxaban hasn't got any deleterious effect on the osseointegration of implants on rats.

Curve progression 25 years after bracing for adolescent idiopathic scoliosis: long term comparative results between two matched groups of 18 versus 23 hours daily bracing.

BACKGROUND: Scoliotic curves do not necessarily stop progressing at skeletal maturity. The factors that influence curve behavior following bracing are not fully determined. Our objectives were to evaluate the loss of the scoliotic curve correction in a cohort of patients treated with bracing during adolescence and to compare the outcomes of 18 versus 23 h of bracing at a mean of 25 years post brace removal. METHODS: Seventy-seven patients, who were successfully treated for Adolescent Idiopathic Scoliosis with Βoston brace, were re-evaluated 25 years after the end of their treatment. Patients were further divided in 2 matched groups; those wearing the brace for 23 h and those not wearing the brace at school-time, limiting the application of the brace to 18 h. The mean scoliotic curve was compared between groups before, during, just after bracing and 25 years post bracing. Validated in patients' native language forms of Short Form 36 and Oswestry Disability Index questionnaires were used to compare the quality of life between groups 25 years post bracing. RESULTS: The mean age of the cohort was 40.4 (±3.2) years. They underwent long term follow up at a mean of 25.16 (±2.69) years after brace removal. The mean cohort scoliotic curve increased by 3.9 (±6.69) at 25 years since brace removal. There was however no significant difference in the mean Cobb angle of the cohort between pre brace and long term follow up period (p = 0.307). The 18 and 23 h application groups were comparable according to demographics and several bracing and scoliotic curve parameters. There was no significant difference in the mean curve magnitude between 18 and 23 h application groups at brace removal (p = 0.512) and at 25 years follow-up (p = 0.878). There was also no significant difference in the mean score of Quality of Life questionnaires between groups at long term follow up. CONCLUSION: Scoliotic curves do not necessarily stop progressing after bracing. Bracing is effective treatment method with good long term results in appropriate patients. Since compliance was not objectively measured, we don't feel confident to give any indication about everyday dosage.

Fracture Rate, Quality of Life and Back Pain in Patients with Osteoporosis Treated with Teriparatide: 24-Month Results from the Extended Forsteo Observational Study (ExFOS).

We describe the pre-planned interim analysis of fracture outcomes, health-related quality of life (HRQoL) and back pain in patients with severe osteoporosis treated with teriparatide for up to 24 months in the Extended Forsteo (Forsteo(®) is a registered trade name of Eli Lilly and Company) Observational Study (ExFOS), a prospective, multinational, observational study. Data on incident clinical fractures, HRQoL (EQ-5D questionnaire) and back pain [100 mm visual analogue scale (VAS)] were collected. The number of patients with fractures was summarised in 6-month intervals and fracture rate over each 6-month period was assessed using logistic regression for repeated measures. Changes from baseline in EQ-5D and back pain VAS were analysed using mixed models for repeated measures. Of 1454 patients in the active treatment cohort, 90.6 % were female and 14.4 % were taking glucocorticoids. During teriparatide treatment (median duration 23.7 months), 103 patients (7.1 %) sustained a total of 122 incident clinical fractures (21 % vertebral, 79 % non-vertebral). A 49 % decrease in the odds of fractures and a 75 % decrease in the odds of clinical vertebral fractures were observed in the >18- to 24-month period versus the first 6-month period (both p < 0.05). EQ-5D scores and back pain VAS scores were significantly improved from baseline at each post-baseline observation during teriparatide treatment. In conclusion, patients with severe osteoporosis showed a significant reduction in the incident fracture rate during 24 months of teriparatide treatment in routine clinical practice, accompanied by a significant improvement in HRQoL and reduction in back pain. Results should be interpreted in the context of the non-controlled design of this observational study.

Teriparatide use during an economic crisis: baseline data from the Greek cohort of the Extended Forsteo Observational Study (ExFOS).

BACKGROUND: The Extended Forsteo Observational Study (ExFOS) is a multinational, non-interventional, prospective, observational study that aims to provide real-life data on patients with osteoporosis treated with teriparatide for up to 24 months. It includes the new indications of osteoporosis in men and glucocorticoid-induced osteoporosis (GIOP). We describe the Greek subpopulation enrolled in this study and compare it with a similar cohort from the previous European Forsteo Observational Study (EFOS). METHODS: Baseline data were collected from the Greek cohort of ExFOS. Data included demographic characteristics, medical and osteoporosis history, disease status, prior use of medications, back pain and quality of life. RESULTS: Baseline data for 439 patients, enrolled at 31 sites, indicated the majority of patients were females (92.3%), elderly [mean (standard deviation; SD) age 70.1 (9.8) years] and slightly overweight [mean (SD) body mass index 26.7 (4.3) kg/m(2)], with very low bone mineral density (mean T-score <-3 in lumbar spine or total hip) and at least one previous fracture (55.1% of patients). Of the 439 patients, 19.8% were osteoporosis treatment naïve, 88.4% had experienced back pain during the previous 12 months, 68.1% had experienced back pain at least fairly often during the previous month and 50.9% reported moderate to severe limitation of activities due to back pain, with a mean (SD) of 4.2 (7.7) days spent in bed because of back pain during the previous month. Most baseline characteristics were numerically similar between the female ExFOS and EFOS cohorts; however, the rate of enrolment was faster in ExFOS (by approximately 45%) and a history of fracture was recorded in 53.8% of female patients in ExFOS versus 74.5% in EFOS. CONCLUSIONS: Greek patients prescribed teriparatide in ExFOS had severe osteoporosis with a high risk of fractures and back pain. Female patients shared similarities with EFOS counterparts, reflecting a constant prescribing profile for use of teriparatide, although a noticeable difference in fracture history between the two study cohorts may indicate a change towards prescribing in less severely affected patients. The economic crisis in Greece did not appear to affect patient enrolment. Data are interpreted in the context of an observational setting.

Measured resection versus gap balancing technique for femoral rotational alignment: a prospective study.

PURPOSE: To compare the measured resection technique and the gap balancing technique for correction of the femoral rotational alignment. METHODS: 57 women and 6 men (mean age, 70 years) with end-stage osteoarthritis and <15º malalignment and <10º flexion contracture of the knee underwent primary total knee arthroplasty through the medial approach using the measured resection technique (n=34) or the gap balancing technique (n=29). Femoral rotational alignment was evaluated before and 7 days after surgery using computed tomography by referencing the 2 posterior condyles to the transepicondylar axis. RESULTS: The 2 groups did not differ significantly in terms of correction of the femoral rotational alignment (3.4º ± 1.4º vs. 3.5º ± 3.1º, p=0.817). CONCLUSION: The measured resection and the gap balancing techniques achieved comparable correction of femoral rotational alignment.

Higher levels of melatonin in early stages of adolescent idiopathic scoliosis: toward a new scenario.

BACKGROUND: The melatonin deficiency hypothesis as a central mechanism in the pathogenesis of adolescent idiopathic scoliosis (AIS) is certainly intriguing. However, the actual role of melatonin remains unclear. The aim of this study was to assess the potential clinical value of melatonin serum level in the pathogenesis and the prognosis of AIS progression in patients who were treated nonoperatively. METHODS: Two groups of patients were enrolled. The study group consisted of patients with AIS aged below 14 years who were treated conservatively. In the second group, that is, the control group, age-matched, weight-matched, and height-matched healthy individuals were enrolled. Blood samples were collected from all patients on visit 1 and the serum levels of melatonin were evaluated with the enzyme-linked immunosorbent assay (ELISA) method. The blood sampling procedure was repeated exactly 1 year later (visit 2). RESULTS: Forty-two patients formed the study group (with AIS) and 29 served as the control group. The mean serum value of melatonin on visit 1 was 19.32 pg/mL for the AIS group and 12.23 pg/mL for the control group. This difference was statistically significant (P = 0.014). One year later, 34 patients from the AIS group and 23 from the control group were reevaluated and the mean serum levels of melatonin were 52.43 and 68.44 pg/mL, respectively. No statistically significant difference was found between the 2 groups (P = 0.235). Statistical analysis of the serum melatonin levels of patients with progressing AIS (>5 degrees of the Cobb angle in 1 y) when compared with patients with stable AIS (P = 0.387) or the control group (P = 0.727) failed to show that the deficiency of melatonin may be associated with the progression of AIS. CONCLUSIONS: Higher melatonin levels were observed in conservatively treated patients with AIS, whereas melatonin deficiency was not associated with AIS progression in this study. LEVEL OF EVIDENCE: Level III-case-control study.

Judo-related traumatic posterior sternoclavicular joint dislocation in a child.

Judo is a combat sport with high risk of injury. We present a rare case of traumatic left posterior sternoclavicular (SC) joint dislocation, inflicted to a 12-year-old boy during a judo contest. An extensive literature review did not reveal any case of posterior SC joint dislocation in judo. The patient was treated with closed reduction under general anesthesia. At 2-year follow-up, his left upper extremity had full range of motion, and he did not complain of any residual symptoms. He decided to discontinue judo training; however, he participates in other physically demanding sports. Although not often encountered, posterior SC joint dislocation is a challenging and critical medical problem that can be fatal if not promptly diagnosed and treated on time and should be considered in the differential diagnosis of trauma-related anterior chest pain.

Leflunomide addition in patients with articular manifestations of psoriatic arthritis resistant to methotrexate.

In contrast to rheumatoid arthritis, in psoriatic arthritis (PsA), the efficacy of disease-modifying antirheumatic drugs (DMARDs) combination has not been documented. We conducted a retrospective study to evaluate the effectiveness of leflunomide (LEF) addition in 11 PsA patients with articular manifestations that failed to respond to methotrexate (MTX) monotherapy [disease activity score in 28 joints (DAS28) > 3.2)]. Eight of them, all with moderate disease activity (DAS28 < 5.1) at baseline, tolerated the combination. A statistically significant improvement of the mean DAS28, based on erythrocyte sedimentation rate (ESR), and its variables, and C-reactive protein (CRP) at 12-16 weeks after LEF addition was observed. Mean change of DAS28 in patients with polyarticular disease did not differ compared with those with oligoarticular. Based on the European League Against Rheumatism (EULAR) response criteria, none of our patients achieved a good response, seven had a moderate response, and one was a non-responder. The two patients with the lower DAS28 at baseline attained low disease activity (LDA, DAS28 ≤ 3.2), while none reached remission (DAS28 ≤ 2.6). Achievement of clinical remission or at least LDA has been recently proposed as the goal of treatment in PsA. Our results imply that LEF addition may serve as an alternative therapeutic modality for patients with moderately active PsA and, as lower as possible, residual disease activity after the initial therapy with MTX alone.

Architectural differences between the hamstring muscles.

The purpose of this study was to understand the detailed architectural properties of the human hamstring muscles. The long (BFlh) and short (BFsh) head of biceps femoris, semimembranosus (SM) and semitendinosus (ST) muscles were dissected and removed from their origins in eight cadaveric specimens (age 67.8±4.3 years). Mean fiber length, sarcomere length, physiological cross-section area and pennation angle were measured. These data were then used to calculate a similarity index (δ) between pairs of muscles. The results indicated moderate similarity between BFlh and BFsh (δ=0.54) and between BFlh and SM (δ=0.35). In contrast, similarity was low between SM and ST (δ=0.98) and between BFlh and SM (δ=1.17). The fascicle length/muscle length ratio was higher for the ST (0.58) and BFsh (0.50) compared with the BFlh (0.27) and SM (0.22). There were, however, high inter-correlations between individual muscle architecture values, especially for muscle thickness and fascicle length data sets. Prediction of the whole hamstring architecture was achieved by combining data from all four muscles. These data show different designs of the hamstring muscles, especially between the SM and ST (medial) and BFlh and BFsh (lateral) muscles. Modeling the hamstrings as one muscle group by assuming uniform inter-muscular architecture yields less accurate representation of human hamstring muscle function.

Serum intact-parathyroid hormone level following total knee arthroplasty.

PURPOSE: To evaluate short-term parathyroid hormone (PTH) secretion following total knee arthroplasty (TKA). METHODS: 119 Caucasian postmenopausal women aged 49 to 81 (mean, 69.8) years who underwent TKA for end-stage knee osteoarthritis were included. Serum levels of intact-PTH, calcium, phosphorus, and creatinine were evaluated pre- and post-operatively (on days -1 and 7). Creatinine clearance was also calculated. RESULTS: In 67 of the patients, serum intact-PTH levels decreased after TKA; this sample proportion was not significant (p=0.82). In 16 of the patients, such levels elevated abnormally (above normal range). In the remaining 36 patients, such levels elevated within the normal range. Therefore, the mean serum intact- PTH level of all patients increased slightly after TKA (45.4 vs. 45.3, p=0.162). The serum intact-PTH level did not correlate to body weight (r=-0.045, p=0.624), patient age (r=-0.061, p=0.508), serum creatinine level (r=0.084, p=0.366), and clearance of creatinine (r=-0.037, p=0.692). CONCLUSION: In most postmenopausal women, the serum intact-PTH level decreased moderately following TKA, but in some, the level was abnormally elevated. This may interfere the prosthesis incorporation process.

Radial head replacement with the MoPyC pyrocarbon prosthesis.

BACKGROUND: Radial head fractures often pose therapeutic dilemmas. We present the early results of patients who underwent radial head replacement with the MoPyC prosthesis (Bioprofile, Tornier, Saint-Ismier, France). MATERIALS AND METHODS: We re-evaluated patients who underwent post-traumatic radial head resection and implantation of the MoPyC prosthesis due to pain and motion restriction. All patients underwent radiographic evaluation. Clinical evaluation was performed using the Broberg-Morrey and the Mayo Elbow Performance Score (MEPS) scales. RESULTS: Thirty-two patients (20 men, 12 women; mean age, 54 years; 22 dominant upper limbs) were evaluated. Twenty had a comminuted radial head fracture (Mason IV, 15; Mason III, 5), 2 from radial head fracture malunion, and 10 had complex elbow injuries (comminuted radial head fractures with ligamentous ruptures with or without coronoid process fractures). Mean follow-up was 27 months (range, 21-46 months). The mean results at the latest follow-up were flexion-extension, 130° (range, 105°-150°); pronation, 74° (range, 60°-80°); and supination, 72° (range, 60°-80°). No laxity was evident during valgus and varus stress tests. Mean grip strength was 96% of the contralateral side. Broberg-Morrey scores were excellent in 33%, good in 44%, and fair in 23%. MEPS results were excellent in 80%, good in 17%, and fair in 3%. There were 6 cases of periprosthetic lucencies or osteolysis of the radius without any clinical signs of loosening. CONCLUSIONS: Radial head replacement with the MoPyC pyrocarbon prosthesis (when performed in carefully selected patients) yields satisfactory results regarding range of motion and function of the elbow joint.

Efficacy of leflunomide addition in relation to prognostic factors for patients with active early rheumatoid arthritis failing to methotrexate in daily practice.

The recommendations of the European League Against Rheumatism (EULAR) for the management of rheumatoid arthritis (RA) suggest a different therapeutic approach to methotrexate (MTX) resistance according to the presence or absence of poor prognostic factors. Retrospectively, in our patients with active early RA (disease activity score in 28 joints (DAS28) > 3.2) that failed to respond to initial MTX monotherapy, we investigated whether leflunomide (LEF) addition had a different efficacy when associated with the presence or absence of poor prognostic factors. Of the 20 patients who received LEF, 15 (2 males and 13 females) tolerated the combination. Five patients had no poor prognostic factors, and 4 (80%) of those patients achieved remission or low disease activity (LDA) according to DAS28 and also a good response with the EULAR criteria. Of the 10 patients with at least one poor prognostic factor, remission or LDA occurred in 4 (40%) of the patients, and a good EULAR response was obtained in 3 (30%) of the patients. By Fisher's exact test, no significant difference was found between the two groups of patients in remission or LDA (p = 0.28) according to DAS28 and a good response (p = 0.12) with the EULAR criteria. In all patients with an inadequate response to the LEF+MTX combination, the substitution of a TNF inhibitor for LEF or the addition of a TNF inhibitor to the combination led to remission or LDA. Large studies are required to investigate the efficacy of LEF addition in relation to prognostic factors in patients with active early RA that did not respond to the initial therapy with MTX alone.

In vivo and in vitro examination of the tendinous inscription of the human semitendinosus muscle.

The aim of this study was to examine the tendinous inscription (TI) of the human semitendinosus (ST) muscle using dissection (cadavers) and ultrasound (in vivo). Ultrasonography (US) scans were taken in 18 young males at rest and at maximum voluntary contraction (MVC). Further, the ST was dissected and removed from its origins in 10 cadaveric specimens (5 cadavers). The cadaveric long arm of the TI was 6.67 ± 0.64 cm (6.45 ± 1.21 in US) while the shorter arm was 2.39 ± 0.38 cm (1.99 ± 0.75 in US). The angle formed by the two TI arms ranged from 53.19 (US) to 56.05° (cadavers) while more superficial fascicles intersected the inscription at significantly higher angles (range 31.98 ± 6.15 to 34.69 ± 7.71°) compared with deeper fascicles (p < 0.05). Fascicle length did not differ between compartments, but it was significantly smaller in superficial compared with deeper layers (p < 0.05). With the exception of the angle between the TI arm and the deep aponeurosis, all measured angles as well as the length of the long arm of the TI increased significantly from rest to MVC (p < 0.05). The role of the TI probably lies in the local interconnections with the fascicles of either compartment, which upon contraction is such that the ST muscle contracts as one muscle. However, the TI arm morphology changes from rest to MVC, indicating a nonuniform displacement of the TI, mainly between the superficial and deeper layers of the muscle.

Reduction of Acute Anterior Dislocation with the FARES Method.

INTRODUCTION: The FARES (Fast, Reliable, and Safe) method is a new way to reduce acute anterior glenohumeral dislocations that combines the application of gentle longitudinal traction, vertical oscillation movements, and abduction and external rotation of the arm. STEP 1 POSITION THE PATIENT: Place the patient supine on a stretcher, with his/her elbow extended, and advise him/her to hold the stretcher with the opposite hand. STEP 2 BRIEF THE PATIENT: Convince the patient that his/her cooperation is necessary for a better outcome. STEP 3 HOLD THE ARM: Holding the patient's hand with both of your hands, with his/her elbow extended and forearm in neutral rotation, start the procedure at 30° of shoulder abduction. STEP 4 APPLY TRACTION AND ADD OSCILLATIONS: Applying gentle longitudinal traction to keep the arm extended, add gentle vertical oscillating movements. STEP 5 ABDUCT AND EXTERNALLY ROTATE THE ARM: Gradually abduct the arm to 90° and then gradually externally rotate the arm to achieve full external rotation. STEP 6 ACHIEVE REDUCTION: The dislocation is usually reduced once 120° to 150° of shoulder abduction has been achieved. RESULTS: In our previously published prospective randomized study, the FARES method was compared with the Hippocratic and the Kocher methods12. WHAT TO WATCH FOR: IndicationsContraindicationsPitfalls & Challenges.

The serum levels of Receptor Activator of Nuclear Factor-κB Ligand, bone-specific alkaline phosphatase, osteocalcin and osteoprotegerin do not correlate with the radiographically assessed severity of idiopathic hip and knee osteoarthritis.

OBJECTIVES: Determination of the serum levels of Receptor Activator of Nuclear Factor-Κb Ligand, bone-specific alkaline phosphatase, osteocalcin and osteoprotegerin in patients suffering from osteoarthritis of varying severity and healthy controls and correlation of these results with the patients' age and the radiographically assessed severity of the disease. DESIGN AND METHODS: Patients suffering from hip (n=58) or knee (n=117) osteoarthritis and matched controls (n=19) were enrolled in this study. Patients underwent physical examination and standard radiographic evaluation before blood sampling. RESULTS: The serum levels of osteoprotegerin were positively correlated with age in all groups, whereas those of osteocalcin in the 'knee' group only. Osteoarthritis' severity and location did not have a statistically significant impact on the mean serum level of any marker in both groups. CONCLUSIONS: Based on our results, none of the studied markers can serve as a surrogate for radiographic imaging in patients suffering from hip and knee osteoarthritis.

Serum levels of bone turnover markers following total joint arthroplasty.

PURPOSE: To evaluate changes in serum levels of bone turnover markers during the first year following a total hip or knee arthroplasty (THA or TKA, respectively). METHODS: 34 women and 13 men (mean age, 68 years) with idiopathic hip or knee osteoarthritis underwent elective THA or TKA. The serum levels of (1) osteoprotegerin, (2) nuclear factor-kappa B ligand (RANKL), (3) osteocalcin, and (4) bone-specific alkaline phosphatase (b-ALP) were determined in each patient on preoperative day 1 and postoperative day 3 and 7, and month 2, 4, 6, 8, 10, and 12. RESULTS: All 4 markers changed significantly over the 12-month period. At month 12, values of all markers did not return to their preoperative levels uniformly. At month 8, the serum levels of osteoprotegerin, osteocalcin, and b-ALP remained higher than their respective preoperative values. The serum levels of RANKL gradually decreased after month 2, rendering this marker a potential index for fixation. CONCLUSIONS: Bone turnover markers change following arthroplasties. Postoperative month 8 seems to be a milestone in the normal course of these markers.

Muscle architecture variations along the human semitendinosus and biceps femoris (long head) length.

The purpose of this study was to examine whether muscle architecture of the long head of biceps femoris (BF) and semitendinosus (ST) muscles varies along their length. The ST and BF muscles were dissected and removed from their origins in eight cadaveric specimens (age range 67.8-73.4 years). One-way analysis of variance designs were used to compare fascicle length (FL), pennation angle (PA) and muscle thickness (MT) between proximal, mid-belly and distal positions. Tendon and muscle length properties were also quantified. For the BF muscle, one-way analysis of variance tests showed a higher PA (23.96±3.82°) and FL (7.12±0.48 cm) proximally than distal positions (PA=17.78±1.95° and FL=6.35±0.89 cm, respectively). For the ST, there was a significantly (p<0.05) lower PA (8.81±1.22°) and FL (13.10±1.54 cm) proximally than distally (PA=14.69±1.09° and FL=15.49±2.30 cm, respectively). Muscle thickness significantly increased from distal to more proximal positions (p<0.05). These data suggest that the ST and BF architecture is not uniform and that measurement of these parameters largely depends on the measurement site. Modeling these muscles by assuming a uniform architecture along muscle length may yield less accurate representation of human hamstring muscle function.