Energy expenditure and activity of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees.

OBJECTIVE: To quantify the energy efficiency of locomotion and free-living physical activity energy expenditure of transfemoral amputees using a mechanical and microprocessor-controlled prosthetic knee. DESIGN: Repeated-measures design to evaluate comparative functional outcomes. SETTING: Exercise physiology laboratory and community free-living environment. PARTICIPANTS: Subjects (N=15; 12 men, 3 women; age, 42+/-9 y; range, 26-57 y) with transfemoral amputation. INTERVENTION: Research participants were long-term users of a mechanical prosthesis (20+/-10 y as an amputee; range, 3-36 y). They were fitted with a microprocessor-controlled knee prosthesis and allowed to acclimate (mean time, 18+/-8 wk) before being retested. MAIN OUTCOME MEASURES: Objective measurements of energy efficiency and total daily energy expenditure were obtained. The Prosthetic Evaluation Questionnaire was used to gather subjective feedback from the participants. RESULTS: Subjects demonstrated significantly increased physical activity-related energy expenditure levels in the participant's free-living environment (P=.04) after wearing the microprocessor-controlled prosthetic knee joint. There was no significant difference in the energy efficiency of walking (P=.34). When using the microprocessor-controlled knee, the subjects expressed increased satisfaction in their daily lives (P=.02). CONCLUSIONS: People ambulating with a microprocessor-controlled knee significantly increased their physical activity during daily life, outside the laboratory setting, and expressed an increased quality of life.

Precision and accuracy of an ankle-worn accelerometer-based pedometer in step counting and energy expenditure.

BACKGROUND: Walking is a widely used approach to increase physical activity levels in obese patients. In this paper, we investigate the precision and accuracy of an ankle-worn dual-axis accelerometer (Stepwatch) and investigate its potential application as a predictor of energy expenditure. METHODS: Twenty healthy subjects (10 lean, 10 obese) wore spring-levered (Accusplit), piezoelectric (Omron HF-100), and Stepwatch pedometers. Subjects walked on a treadmill at 1, 2, and 3 mph and in a hallway at 1 and 1.85 mph, during which energy expenditure was measured. RESULTS: The Stepwatch counted 99.7 +/- 0.67% (mean +/- SEM) of the manual counts. In comparison, the Omron pedometer counted 61 +/- 3.3% and the Accusplit counted 26 +/- 2.8% of the manual counts at 1 mph although all pedometers were accurate (> 98% of counts) at 3 mph. In repeated measures, the Stepwatch produced negligible variance (SD = 0.36) over all speed whereas the other pedometers showed a large amount of variance at all speed (SD = 4-13). Stepwatch counts were predictive of walking energy expenditure corrected by weight (r2 > 0.8). CONCLUSION: The counts from the Stepwatch were virtually identical to the manual counts from a trained investigator and provided a reliable predictor of walking energy expenditure.

Arthrodesis of the shoulder after tumor resection.

UNLABELLED: Functional outcomes of patients with arthrodesis after resection of a shoulder girdle neoplasm are only sparsely reported. Fusion of the shoulder can be done as a primary reconstruction or secondarily for salvage of a failed limb-sparing procedure. We retrospectively reviewed 21 patients at a mean followup of 11 years. In eight patients, arthrodesis was done as the primary reconstruction and in 13 patients as the secondary procedure. There were no local recurrences, and no patient had metastatic disease develop. The overall Toronto extremity salvage and Musculoskeletal Tumor Society scores were 81% (range, 46-97) and 23 points (range, 17-26), respectively. There was no difference with respect to function between patients who had their arthrodesis as a primary or secondary procedure. Eight of 21 patients (43%) had a complication that required major surgical intervention. Shoulder arthrodesis as a limb salvage procedure after tumor resection provides good function independent of whether the procedure is done primarily or secondarily. Because of the high complication rate, future efforts must be directed at surgical methods to decrease such complications. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines to Authors for a complete description of levels of evidence.

Partial weight-bearing gait using conventional assistive devices.

OBJECTIVE: To determine if subjects can offload the right lower extremity to a targeted amount of weight bearing using assistive devices. DESIGN: Case series. SETTING: Motion analysis laboratory. PARTICIPANTS: Ten healthy subjects (5 men, 5 women) without lower-extremity injury and minimal experience using ambulatory aids. INTERVENTIONS: Before data collection subjects were trained by a physical therapist to offload the right lower extremity by 50% by using an assistive device and a bathroom scale for feedback on weight reduction. MAIN OUTCOME MEASURES: Vertical ground reaction force was measured by using forceplates while subjects walked at a self-selected speed by using a 3-point partial weight-bearing (PWB) gait pattern with axillary crutches, forearm crutches, and wheeled walker. We also measured vertical ground reaction force by using a single-point cane. RESULTS: Each gait aid significantly reduced the right lower-extremity peak vertical ground reaction force. Participants were able to achieve the target of approximately 50% weight reduction with the axillary (50% reduction) and forearm (56% reduction) crutches. The wheeled walker resulted in a peak vertical load of 64% of body weight, which was in excess of the target load. A single-point cane produced a peak vertical load of 76% of body weight. CONCLUSIONS: By using a bathroom scale, healthy subjects could be trained to achieve a target goal of 50% PWB with axillary and forearm crutches. A wheeled walker resulted in weight bearing greater than the target of 50% of body weight. Subjects were able to offload the right lower extremity by about 25% of body weight by using a single-point cane.

Electromyographic activity in the immobilized shoulder girdle musculature during contralateral upper limb movements.

The purpose of this study was to quantify electromyographic (EMG) activity in the immobilized shoulder girdle musculature at rest and during a battery of contralateral upper limb activities. Six asymptomatic men, aged 22 to 33 years, volunteered to participate. Fine-wire (supraspinatus, infraspinatus) and surface (deltoids, trapezii, biceps, serratus anterior) electrodes recorded the mean peak normalized (percent maximal voluntary contraction [%MVC]) EMG activity from each immobilized muscle at rest and during slow, fast, and incrementally resisted contralateral upper limb motions (5, 15, and 25 lb). EMG activity in all muscles was low during quiet immobilized standing (<1.5% maximal voluntary contraction [MVC]). During slow contralateral upper limb motions, activity ranged from 0.7% to 51.6% MVC (highest in trapezii) and was less than 15% MVC in the supraspinatus, infraspinatus, and anterior deltoid. Bimanual jar opening increased biceps activity from 7.8% to 16.1% MVC. During fast contralateral upper limb motions, peak infraspinatus activity increased to 56.7% during a fast straightforward reach. Supraspinatus activity was relatively high during all resisted backward-pulling motions (25.2%-32.1% MVC), whereas resisted forward reaching produced relatively little activity in the anterior deltoid, supraspinatus, infraspinatus, or biceps. Several slow and fast motions produced high trapezius activity (>45% MVC) with low supraspinatus, biceps, and anterior deltoid activities (<10% MVC). Our findings suggest that (1) immobilized shoulder girdle muscle EMG activity during quiet standing is negligible in asymptomatic individuals; (2) contralateral upper limb motions at self-selected speeds are not likely to be harmful to healing tissues; (3) during early healing periods, patients with biceps-labral injury should minimize bimanual activities, those with supraspinatus injury should avoid backward-pulling motions, and those with infraspinatus injury should avoid fast straightforward reaches; and (4) cross-body, straightforward, or downward reaches at either a slow or fast speed may be appropriately prescribed as rehabilitative exercises that can be initiated while the shoulder remains immobilized.

Rhomboid muscle electromyography activity during 3 different manual muscle tests.

OBJECTIVE: To determine which of 3 previously published rhomboid manual muscle tests (MMTs) elicits the maximal rhomboid electromyographic activity in an asymptomatic population. DESIGN: Criterion standard. SETTING: Motion analysis laboratory at tertiary care medical center. PARTICIPANTS: Eleven male volunteers (age range, 24-40y) without shoulder or neck pain. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak 1-second normalized electromyographic activity in the rhomboid muscle during 8 different MMT positions, including 3 different rhomboid MMT positions (Kendall, Kendall-Alternative, Hislop-Montgomery). RESULTS: The Kendall MMT (78% maximal voluntary contraction [MVC]) produced higher rhomboid electromyographic activity than the Kendall-Alternative (71% MVC) or the Hislop-Montgomery MMT (52% MVC), but the differences were not statistically significant. The posterior deltoid MMT generated the greatest rhomboid electromyographic activity of all MMTs, and 4% to 30% greater rhomboid electromyographic activity than the 3 rhomboid MMTs (P=.0001; posterior deltoid > Hislop-Montgomery). Electromyographic profiles of the Kendall and Kendall-Alternative MMTs were similar, whereas the Hislop-Montgomery MMT produced less upper trapezius activity (P=.0001 vs Kendall and Kendall-Alternative) and more latissimus dorsi activity (P=.0001 vs Kendall-Alternative). The standard MMT positions for the middle trapezius, levator scapula, posterior deltoid, and latissimus dorsi produced the maximal electromyographic activity for their respective target muscles. CONCLUSIONS: The posterior deltoid MMT position should be used to produce maximal rhomboid electromyographic activity for normalization purposes during kinesiologic studies. The Kendall and Kendall-Alternative rhomboid MMT are likely to be clinically indistinct. It is unlikely that clinicians can use standard MMT positions to distinguish rhomboid strength from synergists, such as the levator scapula and middle trapezius muscle, for diagnostic purposes.

Iliofemoral arthrodesis and pseudarthrosis: a long-term functional outcome evaluation.

Reconstruction after the resection of pelvic tumors is a major challenge. It depends on many factors such as age, activity level, type of tumor, its adjuvant treatment, and the extent of the disease. The purpose of the current study was to analyze the functional and oncologic outcomes of patients who had an iliofemoral arthrodesis after resection of a pelvic sarcoma. Between 1981 and 1999, 20 males and 12 females with a mean age of 39.9 years (range, 10-71 years) had an iliofemoral arthrodesis, either as a solid fusion or primary pseudarthrosis, at one institution. The functional outcome was evaluated using the Musculoskeletal Tumor Society and the Toronto Extremity Salvage scores. At a mean followup of 97 months (range, 14-226 months), 15 of 32 patients were alive, all without disease. The radiographic union rate was 86%. The mean overall Musculoskeletal Tumor Society and Toronto Extremity Salvage scores were 64% and 48%, respectively. Patients with a primary solid fusion did functionally better compared with patients who had pseudarthrosis (Toronto Extremity Salvage Score, 76%; Musculoskeletal Tumor Society Score, 71% versus Toronto Extremity Salvage Score, 52%; Musculoskeletal Tumor Society Score, 25%). Biomechanical analysis showed that the loss of motion in the hip is well-compensated. The authors conclude from this series that iliofemoral reconstruction after resection of a pelvic sarcoma provides acceptable and durable long-term results, not only from the oncologic, but also from the functional perspective.

Effect of scapular protraction and retraction on isometric shoulder elevation strength.

OBJECTIVES: To examine the effect of scapular protraction (SP) and scapular retraction (SR) on isometric shoulder elevation strength measured in the sagittal plane and to test the hypothesis that strength would be significantly reduced when tested in the SP position relative to the neutral resting scapular position (SN). DESIGN: Prospective before-after trial. SETTING: Multidisciplinary sports medicine center. PARTICIPANTS: Ten healthy volunteers (5 men, 5 women) ages 26 to 43 years recruited from the Mayo Clinic, Rochester, MN. INTERVENTIONS: Subjects completed 3 maximal isometric shoulder elevation contractions at 90 degrees of sagittal plane elevation in the SN, SP, and SR positions. The order of scapular positions was varied to minimize fatigue effects. Mean isometric strength values were compared by using Student t tests. MAIN OUTCOME MEASURES: Isometric shoulder elevation strength for the 3 scapular positions. RESULTS: Isometric strength was significantly lower for the SP position compared with the SN position (8.5 +/- 3.4 kg vs 11.1 +/- 4.0 kg, P <.0005) and for the SR position relative to the SN position (7.8 +/- 3.3 kg vs 11.1 +/- 4.0 kg, P <.00003). Strength values did not differ between the SP and SR positions (P =.38). CONCLUSIONS: Movement of the scapula into a protracted or retracted position results in a statistically significant reduction in isometric shoulder elevation strength as measured in this study. Further research is warranted to examine the relationship between scapular position and shoulder muscle function.