Journal of Musculoskeletal Research

Posterior interspinous dynamic stabilization is used increasingly in the treatment of lumbar degenerative spinal conditions, with preliminary evidence for its clinical and biomechanical efficacy emerging. The need remains to define patients who respond best to this form of surgery. This study examined clinical outcomes in 39 patients (21 females) with defined lumbar spinal pathologies, for two years after lumbar surgery augmented with the Device for Intervertebral Assisted Motion (DIAM). Anatomical patient categorization revealed involvement of disc (n=25/39) and facet (n=14/39) lumbar pathology, with clinical indications for surgery being: segmental instability (n=21/39); nerve root compression (n=11/39); and facet joint pain syndrome (n=7/39). Pain, function and satisfaction data were derived from MODEMS self-report questionnaires, which were collected prospectively over a two-year post-operative period. Results showed that L4-5 and L5-S1 were the most common DIAM-implanted spinal levels. Clinically significant post-operative improvement in pain (23.4%) and function (13.5%) occurred between three and twenty-four months. Eleven (of 39) required further lumbar surgery. Nineteen (of 28) were more satisfied at 24 months post-operatively compared to baseline. Disc involvement and segmental instability were the most common presenting lumbar segmental pathologies, yet the least successful in response to surgery augmented with DIAM. Patients with facet involvement reported superior improvement post-operatively compared with those with disc involvement. Patients with facet joint disease demonstrate better outcomes at 24 months following lumbar surgery augmented with DIAM posterior interspinous dynamic stabilization, compared with those presenting with disc pathology.

Most of the biomechanical experiments, which validate vertebral finite-element models, deal with vertebral bodies in axial compression. In standing position, gravity loads can induce bending on the last thoracic and first lumbar vertebrae. Hence, the purpose of the study was to evaluate the strength of vertebrae submitted to anterior bending. The boundary conditions were carefully assessed for further validation of finite-element models. Fifteen vertebrae (T11–L2) were tested until failure. The load was applied on the anterior part of the vertebral body and distributed to the whole vertebral body through a polymethylmetacrylate layer. The 3D position of the origin of the force relative to the vertebra was assessed using a motion-capture system and 3D reconstructions of the testing device. The mean failure load was equal to 2098 N. Ninety-five percent of the vertebrae failed through a vertical displacement smaller than 1.5 mm. Rotations were weak during the test (< 1°), therefore the protocol can be simplified by removing the motion capture system if the initial 3D origin of the load is known. To our knowledge, it is the first protocol that quantifies the strength of whole vertebrae under anterior bending. It collects with accuracy all the data necessary for one-to-one vertebral finite-element model validations.

Purpose: The purpose of this study was to assess the association of the knee flexion excursion to the vertical center-of-mass (COM) amplitude and to the lower-extremity muscle work during stance phase for subjects with knee osteoarthritis. Method: Twenty subjects scheduled for total knee replacement and 20 controls performed level walking during standard gait analysis. Dependent variables included stance-phase knee flexion excursion, vertical COM amplitude, and lower-extremity muscle work. Results: Compared to healthy control, subjects with knee osteoarthritis walked with significantly less stance-phase knee flexion and vertical COM excursion. Knee flexion excursion was found to have a strong positive correlation to vertical COM amplitude. The lower-extremity muscle work during single stance phase was found to have a moderate negative correlation to vertical COM amplitude. Conclusions: Osteoarthritis of the knee alters both the stance-phase knee flexion and vertical COM excursions. As these variables show a strong positive relation, efforts to restore stance-phase knee flexion based on the 3rd determinant of gait require a new justification.

Objective: To evaluate the association between vitamin supplements and the incidence and progression of radiographic knee osteoarthritis (OA). Study Design: Prospective cohort. Methods: Men and women aged 40 years and older (N = 2239) participating in the community-based Clearwater Osteoarthritis Study (1988–current) with biennial, sequential radiographs. The Lawrence & Kellgren ordinal scale was used to determine evidence of the study outcome, radiographic knee OA, and progression of radiographic knee OA. The study exposure was baseline history of self-reported vitamin supplement usage. Results: Individuals without baseline knee OA who self-reported vitamin supplement usage were 12% less likely to develop knee OA than were those individuals who self-reported no vitamin supplement usage (RR = 0.88; 95% C.I. 0.86–0.89). Those with baseline knee OA who self-reported vitamin supplement usage were 7% less likely to experience knee OA progression than were those individuals who self-reported no vitamin supplement usage (RR = 0.93; 95% C.I. 0.87–0.99). Conclusion: After consideration of BMI, gender, age, history of knee trauma, exercise and vitamin supplement usage prior to study baseline, these findings suggest that vitamin supplement usage may play a protective role in knee OA. Vitamin supplements may be a cost-effective strategy to reduce the incidence and/or slow the progression of knee OA. As many approved OA drugs are accompanied by adverse side effects, the role of vitamin supplements in the development and progression of knee OA warrants further investigation.

The primary diabetes-related health concerns are neuropathy and cardiovascular changes. Connective tissue changes can also affect quality of life by increasing ligament and joint capsule stiffness, impairing proprioception, limiting function, and leading to greater risk of falling. Our objectives were to evaluate effects of Type I diabetes and exercise on medial collateral ligament properties and overall knee-joint stiffness and stress relaxation. Thirty-four male Sprague–Dawley rats, approximately two months old, were divided into three groups—sedentary controls (n=10), sedentary diabetics (n=10) and exercised diabetics (n=14). Diabetes was induced by streptozotocin injection. Exercised rats ran 5 days/week, 1 hr/day, at 20 m/min. All animals were sacrificed seven weeks after induction of diabetes. Stiffness and stress relaxation of the whole knee joint was tested in distraction and anterior–posterior tibial displacement. The joint capsule and knee ligaments were then sectioned, preserving the medial collateral ligament (MCL). The MCL structural properties were tested by knee distraction at a flexion angle of 40°. Whole joint stiffness was 23% higher for anterior tibial displacement in the exercised diabetic group, and 31% higher for posterior tibial displacement, compared to controls. Whole joint stress relaxation in distraction was 25% lower for the exercised diabetic group. No differences were found for MCL properties. Diabetes and exercise clearly increased joint stiffness. The effects may be due to tissue adaptation, but appear more likely to be due to increased blood flow that promotes increased tissue glycation in the joint capsule.

Introduction: To follow fracture healing, radiography is commonly used, but it is not sensitive to the early stages of this healing process when nonossified callus is formed. Hence, radiography can lag behind the physiological events of bone healing by some weeks. Although the use of ultrasound for fracture diagnosis has been reported previously, mainly in children, the clinical use of ultrasound to follow fracture healing has rarely been commented on. The goal of the current study was to test the efficiency and efficacy of ultrasound as an alternative method for follow-up of fracture healing. Material and Methods: During a one-year period, 12 patients—six with proximal fibula fracture and six with proximal metatarsal fractures—were followed by ultrasonographic examination in parallel with the routine radiographs. Results: The ultrasound examinations revealed callus formation after one month, with the early signs of healing after ten days. Early callus was first seen on radiographs after a month. Conclusion: Ultrasound was found to be a good modality to follow up fracture healing in long bones. This modality can reduce the amount of radiation received by the patients in the follow-up of fractures, and may shorten the immobility period and hence the recovery time of returning to normal function.

Study design: Case study. Background: To date, there is little research that has examined the association of impairments at the hip with cumulative trauma syndromes of the hip. The purposes of this case report are to: (1) describe clinical outcomes for a patient with non-specific bilateral musculoskeletal hip pain associated with recreational walking, (2) explore the relationship between this patient's impairments and her cumulative trauma syndrome at the hip, and (3) integrate biomechanical analysis with this patient's clinical diagnosis. Case description: The patient was a 28-year-old female research assistant who reported anterior bilateral hip pain during recreational walking. After examination, the physical therapist diagnosed primary impairments of hip pain, limited hip flexion range of motion (ROM), and weakness of hip musculature, resulting in her ambulation limitations. Intervention consisted of a home exercise program (HEP) designed to strengthen the iliopsoas, gluteus maximus, and gluteus medius (specifically, the posterior portion), increase extensibility of the IT Band and medial hamstrings, and promote posterior glide of the proximal femur. The patient's HEP was the only intervention she received. There were follow-up telephone conversations, but no clinical re-examination for ten weeks. The patient performed the HEP a total of 41 days over the ten week period. Biomechanical gait analysis was performed pre- and post-intervention. Outcomes: Following intervention, the patient was pain-free during recreational walking, and passive hip flexion ROM and manual muscle testing (MMT) grades of hip musculature improved. Global score on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) improved ten points. Motion analysis, force plate analysis, and electromyography (EMG) showed that maximum hip extension decreased, maximum hip flexion increased, maximum ground reaction force increased, activation of the gluteus maximus increased, while activation of the gluteus medius and tensor fascia latae (TFL) decreased following the intervention. Discussion: This patient's changes in muscle activity following a HEP appear largely consistent with improved symptoms based on theoretical descriptions of a common muscle imbalance (shortened and overactive TFL and weakness of the gluteus maximus and posterior portion of the gluteus medius), thought to contribute to increased femoral medial rotation.