Effect of increased serum 25(OH)D and calcium on structure and function of post-menopausal women: a pilot study.

The purpose was to determine if increasing serum 25(OH)D and calcium in postmenopausal women increased skeletal muscle size, strength, balance, and functional task performance while decreasing muscle fatigue. PCSA of the vastus lateralis increased and ascent of stairs time decreased after 6 months of increased serum 25(OH)D. PURPOSE: The Institute of Medicine recommends ≥ 20 ng/ml of serum 25-hydroxyvitamin D [25(OH)D] for bone and overall health. Serum 25(OH)D levels have been associated with physical performance, postural sway, and falls. The purpose of this study was to determine if increasing postmenopausal women's serum 25(OH)D levels from 20-30 ng/ml to 40-50 ng/ml improved skeletal muscle size, strength, balance, and functional performance while decreasing skeletal muscle fatigue. METHODS: Twenty-six post-menopausal women (60-85 years old) with baseline serum 25(OH)D levels between 20 and 30 ng/ml were recruited. Oral over-the-counter (OTC) vitamin D3 and calcium citrate were prescribed to increase subjects' serum 25(OH)D to levels between 40 and 50 ng/ml, serum calcium levels above 9.2 mg/dl, and PTH levels below 60 pg/ml, which were confirmed at 6 and 12 weeks. Outcome measures assessed at baseline and 6 months included muscle physiological cross-sectional area (PCSA), muscle strength, postural balance, time to perform functional tasks, and muscle fatigue. Repeated measures comparisons between baseline and follow-up were performed. RESULTS: Nineteen subjects completed the study. One individual could not afford the time commitment for the repeated measures. Three individuals did not take their vitamin D as recommended. Two subjects were lost to follow-up (lack of interest), and one did not achieve targeted serum 25(OH)D. Vastus lateralis PCSA increased (p = 0.007) and ascent of stair time decreased (p = 0.042) after 6 months of increasing serum 25(OH)D levels from 20-30 ng/ml to 40-50 ng/ml. Isometric strength was unchanged. Anterior-posterior center of pressure (COP) excursion and COP path length decreased (p < 0.1) albeit non-significantly, suggesting balance may improve from increased serum 25(OH)D and calcium citrate levels. CONCLUSIONS: Several measures of muscle structure and function were sensitive to elevated serum 25(OH)D and calcium levels indicating that further investigation of this phenomenon in post-menopausal women is warranted.

Rehabilitation for limb salvage patients: kinesiological parameters and psychological assessment.

Osteosarcoma is the most frequently occurring primary malignant tumor of bone, especially in adolescence. Treatment involves either limb salvage surgery or amputation with neoadjuvant chemotherapy. This review article discusses the current treatment modalities for osteosarcoma and also compares the gait patterns and psychosocial profiles of patients treated with either limb salvage surgery or amputation for osteosarcoma. Contemporary orthopedic literature on therapeutic options for osteosarcoma patients is reviewed. Background information on the basic principles of kinesiology, with emphasis on studies of gait pattern differences among patients treated with limb salvage versus amputation, is presented. Finally, several studies of the psychologic profiles of patients after these two procedures for osteosarcoma are reviewed. Trends in contemporary orthopedic literature suggest that functional outcomes, in terms of kinesiologic parameters, are comparable for patients treated with either limb salvage or amputation. Both sets of patients reported quality-of-life problems, including difficulty retaining health insurance and finding appropriate employment, social isolation, and poor self-esteem. The management of patients with osteosarcoma includes not only an individualized surgical plan for each patient but also includes awareness of the patients' psychologic and social needs after surgery.

Gait characteristics of patients after proximal femoral replacement for malignant bone tumour.

We analysed the gait characteristics of 15 patients with prosthetic reconstruction of the proximal femur after resection of a malignant bone tumour using stride analysis and measurement of oxygen consumption. Compared with normal volunteers their gait was slower, with less cadence and reduced stride length. The mean net energy cost of free walking was 141% of normal. The degree of asymmetry of the single-limb support time correlated with the free-walking velocity and the net energy cost. If they used a single cane the subjects walked with less cadence, longer stride length, and prolonged single-limb support times. The net energy cost of walking and asymmetry of the single-limb support time had a negative correlation with the strength of the hip abductor muscles. Their walking performance was better than that of six subjects who had hip disarticulation.

Bootstrap prediction and confidence bands: a superior statistical method for analysis of gait data.

Gait analysis studies typically utilize continuous curves of data measured over the gait cycle, or a portion of the gait cycle. Statistical methods which are appropriate for use in studies involving a single point of data are not adequate for analysis of continuous curves of data. This paper determines the operating characteristics for two methods of constructing statistical prediction and confidence bands. The methods are compared, and their performance is evaluated using cross-validation methodology with a data set of the sort commonly evaluated in gait analysis. The methods evaluated are the often-used point-by-point Gaussian theory intervals, and the simultaneous bootstrap intervals of Sutherland et al. The Development of Mature Walking, MacKeith Press, London, 1988 and Olshen et al. Ann. Statist. 17 (1989) 1419-40. The bootstrap bands are shown to provide appropriate coverage for continuous curve gait data (86% coverage for a targeted coverage of 90%). The Gaussian bands are shown to provide inadequate coverage (54% for a targeted coverage of 90%). The deficiency in the Gaussian method can lead to inaccurate conclusions in gait studies. Bootstrap prediction and confidence bands are advocated for use as a standard method for evaluating gait data curves because the method is non-parametric and maintains nominal coverage levels for entire curves of gait data.

Interrelationships of clinical outcome, length of resection, and energy cost of walking after prosthetic knee replacement following resection of a malignant tumor of the distal aspect of the femur.

The relationships between the functional score according to the system of the International Society of Limb Salvage, the extent of resection, energy cost of walking, and gait characteristics were studied in thirty-six patients who had had segmental knee replacement after resection of a malignant tumor of the distal aspect of the femur. The mean free-walking velocity was 62.3 meters per minute (79 per cent of normal), which was a result of decreases in both cadence and stride length. The mean net energy cost during walking was 35 per cent greater than that of normal controls and correlated with the percentage of the femur that had been resected. All patients had decreased single-limb support time on the affected side compared with the unaffected side. There was a weak correlation between the asymmetry of the single-limb support time and the percentage of the femur that had been resected. The mean extensor torque of the affected knee was 30 per cent that of the unaffected knee when one head of the quadriceps muscle had been excised, 19 per cent when two heads had been excised, 4 per cent when three heads had been excised, and 1 per cent when four heads had been excised. The patients who had had an extra-articular resection had lower mean extensor and flexor torques at the knee compared with those who had had an intra-articular resection. The asymmetry of the single-limb support time was inversely related to the residual extensor and flexor torques. The overall score according to the system of the International Society of Limb Salvage ranged from 17 to 29 points (mean, 24.6 points; 82 per cent of normal). The net energy cost, percentage of maximum aerobic capacity, and asymmetry of the single-limb support time had significant negative correlations with the overall functional score. Multivariate analysis showed that the overall functional score and the percentage of the femur that had been resected were the two most important factors that predicted the net energy cost. To our knowledge, this is the first objective validation of the functional score according to the system of the International Society of Limb Salvage. As the net energy cost can be predicted from universally available, inexpensive measures, investigators can easily use it as a clinical and research tool to evaluate prosthetic performance and to assess operative outcome.

The effect of the squat exercise on anterior-posterior knee translation in professional football players.

Although the squat exercise is considered essential for optimal athletic performance, controversy exists regarding the effect on knee stability. The purpose of this prospective study was to determine the effect of squat exercises on in vivo knee joint stability of professional football players. Thirty-two subjects with normal knees participated in a 21-week off-season training program. Subjects performed power squat exercises with barbell loads of 130% to 200% body weight twice weekly. Both knees of each subject were tested by a single examiner with a knee ligament arthrometer before the training program and at 12 and 21 weeks. Passive displacements were recorded at 67, 89, and 133 N with the knee at 30 degrees and 90 degrees of flexion. Active testing was performed with the knee in the same positions. Student's paired t-tests were used to compare pre- and postexercise measures. For all subjects, no significant differences were found between pre- and postexercise results for active and passive tests. Of the 2440 measurements taken, only 8 demonstrated increased excursions greater than 2 mm. This study demonstrates no significant increases in anterior-posterior tibiofemoral translation in athletes using the squat exercise as part of their off-season training program.

Torque production in the shoulder of the normal young adult male. The interaction of function, dominance, joint angle, and angular velocity.

Shoulder torque measurements were obtained from 36 normal young adult males during flexion, abduction, internal rotation, and external rotation. Normative, angle-specific torque measurements were determined under isometric conditions and isokinetically at 48 deg/sec. The effects of dominance, angular velocity, and joint position were determined and a method provided for determining the expected maximal torque at a specific speed and position based upon torque measurements from the contralateral shoulder. This method can be used in cases of unilateral shoulder abnormalities to predict normative torque values for the affected side based on torque measurements from the unaffected shoulder.