Body position determines propulsive forces in accelerated running.

Rapid accelerations during running are crucial for the performance in a lot of sports. While high propulsive forces are beneficial to forward acceleration, vertical forces have to be small to attain high stride frequencies. However, propulsive and vertical force components cannot be altered independently, because the resultant force vector affects the angular momentum of the body. Therefore we hypothesized that propulsive forces in accelerated running mainly depend on body position regardless of performance level. In our cross-sectional study 28 male and 13 female physical education students performed submaximal and maximal accelerations. Ground reaction forces and whole body kinematics were recorded. Higher accelerations were generated by lower, but more forward oriented forces. The orientation of the maximum force vector strongly correlated with the forward lean of the body at toe-off (r=0.93,p

Breast-conserving surgery with resection of the nipple-areola complex for subareolar breast carcinoma.

INTRODUCTION: Breast-conserving therapy for centrally located tumours has in the past been viewed with reservation, but is now an accepted treatment. There is little published evidence, however, to show that it is safe and cosmetically acceptable. METHODS: In a prospective investigation carried out between 1996 and 2002, 44 women had surgery for 45 breast carcinomas with suspected nipple involvement. The breast was conserved and the nipple-areola complex removed. Secondary mastectomy was performed in three women because the tumour was found to reach the resection margin. Forty-one women underwent further observation. The mean tumour size at the time of operation was 18 (range 4-50) mm. Six women received preoperative chemotherapy. RESULTS: Histologically, there were seven preinvasive and 35 invasive cancers. No local failure had occurred at a median follow-up of 51 months. Six women developed distant metastasis, of whom five died. The mean score for cosmetic results (evaluated on a scale of 1-5 where a score of 1 was excellent) was 1.5 for patients and 1.7 for physicians. CONCLUSION: Breast-conserving therapy is a safe and cosmetically acceptable alternative to mastectomy for subareolar breast cancer.

The impact of preoperative breast biopsy on the risk of sentinel lymph node metastases: analysis of 2502 cases from the Austrian Sentinel Node Biopsy Study Group.

Preoperative breast biopsy might cause disaggregation of tumour cells and tumour cell spread. The purpose of this study was to investigate the impact of preoperative biopsy on the rate of metastases to the sentinel lymph node (SLN) of patients with primary breast cancer. We report the results of 2502 patients with primary breast cancer, who were operated, and a sentinel node biopsy was performed. The association of preoperative biopsy with the risk of SLN metastases was examined by regression analyses and tested for possible confounding well-known factors for axillary node metastases. In all, 1890 patients were available for final analyses; 1048 (55.4%) patients had a preoperative diagnosis performed by fine-needle aspiration or core biopsy; 641 (33.9%) patients had a positive SLN when conventional H&E and IHC staining was performed. Patients with preoperative breast biopsy showed a 1.37 times (95% CI, 1.13-1.66) increased risk of SLN metastases on univariate analysis, but this result was not persistent when analysis was adjusted for other relevant factors for axillary node metastases, OR 1.09 (95% CI, 0.85-1.40). In addition, subgroup analyses of the risk for occult micro metastases to the SLN (detected by IHC only) on H&E-negative cases also showed no increased risk associated with preoperative biopsy, OR 1.07 (95% CI, 0.69-1.65). The conclusion, based on the present data, is that preoperative breast biopsy does not cause artificial tumour cell spread to the SLN, with possible negative impact on the prognosis of breast cancer.

Objective diagnosis of equinus during gait prior to and following a tibial nerve block.

A quantitative evaluation technique has been developed to assist the clinician in the diagnosis and treatment of ankle equinus deformity. Specifically, the work focuses on accomplishing two major goals: 1) to develop a reliable set of quantitative criteria to assess the degree of dysfunction of the ankle joint during locomotion in patients with equinus deformity; and 2) to determine the effect of various treatment modalities on the ambulatory performance of patients with equinus deformity. A statistically significant difference in two key gait parameters has been demonstrated between healthy subjects and those with equinus deformity.

Objective identification of ankle equinus deformity and resulting contracture.

A quantitative diagnostic technique is described for identifying contracture at the ankle joint in patients with equinus deformity, hence addressing the shortcoming of the conventional clinical diagnostic procedure. To gain a better understanding of how contracture contributes to equinus deformity, a study was designed that compared the torque about the ankle joint before and after administering a tibial nerve block to equinus patients and to a control group. Functional equinus, manifested by walking and early heel rise, is defined as inadequate dorsiflexion for normal gait. The ability to accurately identify an equinus condition, and contracture as the contributing factor in equinus deformity, has important implications for the type of treatment prescribed and the evaluation of treatment effectiveness.