Introduction. Following tear of its tendon, the muscle undergoes retraction, atrophy and fatty infiltration. These changes are inevitable and considered irreversible and limit the potential of successful repair of musculotendinous units. It was the purpose of this study to test the hypothesis that administration of anabolic steroids can prevent these muscular changes following experimental supraspinatus tendon release in the rabbit. Methods. The supraspinatus tendon was experimentally released in 20 New Zealand rabbits. Musculotendinous retraction was monitored over a period of 6 weeks. The seven animals in group I had no additional intervention, six animals in group II had local and seven animals in group III had systemic administration of nandrolone deconate during six weeks of retraction. At the time of sacrifice, in-vivo muscle performance as well as radiologic and histologic muscle changes were investigated. Results. Supraspinatus retraction was significantly higher in group I (1.8 ± 0.2cm) than in group II (1.5 ± 0.3cm, p = 0.044) or III (1.2 ± 0.3cm, p = 0.001). The reduction in radiological cross sectional area, as a measure for atrophy, was significant in groups I (p = 0.013) and II (p = 0.030) and insignificant in group III (p = 0.149). Histologically, there was no fatty infiltration in the treated groups II (p = 1.000) and III (p = 0.812), but in the untreated group I (p = 0.0312). The work of the respective muscle during one standardized contraction with supramaximal stimulation decreased markedly in groups I (p = 0.056) and II (p = 0.0528), and also but less in group III (p = 0.23). Conclusion. This is the first documentation of prevention of important muscle alterations after chronic retraction of the musculotendinous unit caused by rotator cuff tear. Nandrolone deconate administration in the post tendon release phase prevented fatty infiltration of the supraspinatus muscle and reduced functional muscle impairment caused by myo-tendinous retraction

Goal. The goal of this prospective, non-randomized study is to compare functional and life-quality changes in primary total hip replacement (THR) with minimally invasive anterior (MIA) and direct lateral (DL) approach in six months follow-up. Materials and Methods. Sixty (30 MIA and 30 DL) consecutive patients underwent primary THR were operated by the same senior surgeon. Patients completed functional and life-quality scores (Oxford Hip Score, Harris Hip Score, EQ-5D) before operation and four times (2 and 6 weeks, 3 and 6 months) after THR. Physical examination was taken all times. 15–15 patients underwent MRI examination to adjudge status of abductor muscles. The average patient age was approximately equal in both group. Results. The average OHS values were 13,4; 27,5; 40,9; 45,3; 47,5 in MIA and 15,3; 25,3; 39,7; 43,8; 45 in DL, the average HHS values 43,1; 68,7; 85,3; 91,9; 96,7 in MIA and 43; 58,2; 81,5; 90,2; 93,9 in DL, the average EQ-VAS 41,1; 72,5; 85,9; 87,8; 92,4 in MIA and 55,6; 67,8; 80,6; 84; 91,3 in DL consecutively. In MIA group both functional and life-quality scores showed better results, but for the 3rd postoperative month increases were approximately equal. Abductor muscle strength was significantly greater in MIA group in this period. In the 6th postoperative week Trendelenburg-sign was detected in 24 cases (80%) in DL and in 2 cases (6,7%) in MIA group, but in MIA patients were greater trochanter fractures, which had gone healing and limping was not detected 3 months after surgery. 3 months after surgery Trendelenburg-sign was detected in 2 cases in DL group. In follow-up period residual trochanteric pain was detected in 3 cases in DL but none in MIA group. Two weeks after THR climbing a flight of stairs was normal and public transport could be used by 80% of patients in MIA group. Distance walk was unlimited, support had not needed, daily activities were easy. There were 7 operative complications in MIA group, including 2 greater trochanter fracture, 1 haematoma and 4 transient lateral femoral cutaneous nerve palsy, which showed change for the better after 6 months. Postoperative hip dislocation was not detected. In DL group MRI represented fatty infiltration and atrophy of abductor muscles in most cases. Conclusions. Besides the fact that our learning curve may influence the results. It seems that earlier mobilisation and faster postoperative recovery can be achieved by MIA approach, which have many financial and social benefits. It preserves muscles and tendons, which probably can influence the long-term results. By preventing abductor muscles can assure better gait pattern. Of course additional long-term studies are needed

Introduction. Differing levels of tendon retraction are found in full-thickness rotator cuff tears. The pathophysiology of tendon degeneration and retraction is unclear. Neoangiogenesis in tendon parenchyma indicates degeneration. Hypoxia inducible factor 1(HIF) and vascular endothelial growth factor (VEGF) are important inducers of neoangiogenesis. Rotator cuff tendons rupture leads to fatty muscle infiltration (FI) and muscle atrophy (MA). The aim of this study is to clarify the relationship between HIF and VEGF expression, neoangiogenesis, FI, and MA in tendon retraction found in full-thickness rotator cuff tears. Methods. Rotator cuff tendon samples of 33 patients with full-thickness medium-sized rotator cuff tears were harvested during reconstructive surgery. The samples were dehydrated and paraffin embedded. For immunohistological determination of VEGF and HIF expression, sample slices were strained with VEGF and HIF antibody dilution. Vessel density and vessel size were determined after Masson-Goldner staining of sample slices. The extent of tendon retraction was determined intraoperatively according to Patte's classification. Patients were assigned to 4 categories based upon Patte tendon retraction grade, including one control group. FI and MA were measured on standardized preoperative shoulder MRI. Results. HIF and VEGF expression, FI, and MA were significantly higher in torn cuff samples compared with healthy tissue (p<0.05). HIF and VEGF expression, and vessel density significantly increased with extent of tendon retraction (p<0.04). A correlation between HIF/VEGF expression and FI and MA could be found (p<0.04). There was no significant correlation between HIF/VEGF expression and neovascularity (p>0.05). Conclusion. Tendon retraction in full-thickness medium-sized rotator cuff tears is characterized by neovascularity, increased VEGF/HIF expression, FI, and MA. VEGF expression and neovascularity may be effective monitoring tools to assess tendon degeneration