Normal isometric strength of rotatorcuff muscles in adults.

OBJECTIVES: The most prevalent disorders of the shoulder are related to the muscles of rotator cuff. In order to develop a mechanical method for the evaluation of the rotator cuff muscles, we created a database of isometric force generation by the rotator cuff muscles in normal adult population. We hypothesised the existence of variations according to age, gender and dominancy of limb. METHODS: A total of 400 healthy adult volunteers were tested, classified into groups of 50 men and women for each decade of life. Maximal isometric force was measured at standardised positions for supraspinatus, infraspinatus and subscapularis muscles in both shoulders in every person. Torque of the force was calculated and normalised to lean body mass. The profiles of mean torque-time curves for each age and gender group were compared. RESULTS: Our data showed that men gradually gained maximal strength in the fifth decade, and showed decreased strength in the sixth. In women the maximal strength was gained in the fourth decade with gradual decline to the sixth decade of life. The dominant arm was stronger in most of the tested groups. The torque profiles of the rotator cuff muscles in men at all ages were significantly higher than that in women. CONCLUSIONS: We found previously unrecognised variations of rotator cuff muscles' isometric strength according to age, gender and dominancy in a normal population. The presented data may serve as a basis for the future studies for identification of the abnormal patterns of muscle isometric strength in patients with pathology of the rotator cuff muscles. Cite this article: Bone Joint Res 2013;2:214-19.

The role of activin A in the human osteoblast cell cycle: a preliminary experimental in vitro study.

Animal studies have previously shown that activin A enhances osteoblast proliferation IN VITRO and increases bone formation and bone mechanical strength IN VIVO. For the further understanding of its action in human osteoblast, we studied the pattern of a cell cycle response to the treatment with activin A. We hypothesize that activin A alters the cell cycle pattern of human osteoblast. Primary cultures of human osteoblast-like cells were treated by activin A in a biologically effective concentration (100 ng/mL). The cells in cultured samples were counted, assayed for cellular alkaline phosphatase activity and calcitonin expression, LDH activity in the medium, cellular BrdU incorporation, cell cycle cytometry and compared to untreated controls. The treated by activin A cells responded by a significant shift toward the G1 phase of the cell cycle with parallel decrease in cell death rate (lower LDH activity and less necrotic cells in cytometric analysis). The treated cells also showed a lower alkaline phosphatase activity and calcitonin expression, indicating their undifferentiated state, and didn't change their proliferation rate. The number of cells in culture increased following treatment with activin A. We show that activin A increases the net osteoblast number in culture by reducing the cell death rate without affecting the cell proliferation. These findings should be part of cellular pathways that are involved in the initial stages of bone tissue generation.

A simple technique for the placement of Schanz screws into bone using minimal radiologic control.

The insertion of Schanz screws into the bone during external-fixation procedures in trauma and elective orthopaedic surgery is usually done under röentgenologic control. In order to minimize irradiation exposure for the patients, as well as surgeons, we describe a simple method of Schanz screw placement. The röentgenologic control of the position of the half-pins is only necessary at the beginning and the end of the procedure. This technique is simple, shortens the operating time and reduces the amount of radiation exposure to both the patient and surgeon. It is a valuable technique in many resource-poor environments who do not have the facilities for an image intensifier fluoroscopy or C-arm as well as in austere situations such as during military operations.

Walking ability following knee arthroplasty: a prospective pilot study of factors affecting the maximal walking distance in 18 patients before and 6 months after total knee arthroplasty.

Functional assessment of patients before and after prosthetic knee arthroplasty is based on clinical examination, which is usually summarized in various knee scores. The present study proposes a different and more subject orientated assessment for functional grading of these patients by measuring their maximal distance of walking ability, which is not apparent from the conventional outcome scores. Eighteen consecutive patients with knee osteoarthritis were evaluated for their knee and knee functional scores (The Knee Society clinical rating system) and for the maximal distance of their walking ability before and 6 months after knee arthroplasty. Specially designed walking ability grading was used for evaluation of walking on walkway. The pre- and post-operative knee scores and maximal walking distance and grading were statistically compared. A significant improvement in the knee and functional scores following surgery was observed. But the maximal walking ability grades and distances did not change significantly following surgery, showing a high relation between pre- and post-operative values. The limitation in post-operative walking was due to the revealed additional health disabilities, not related to the affected knee. Therefore we suggest that pre-operative evaluation of walking abilities should be taken into consideration both for patients' selection and timing of surgery and also for matching of patients' expectation from outcome of prosthetic knee arthroplasty.

Technique for closed reduction of femoral shaft fracture using an external support device.

Closed reduction of femoral shaft fractures for intra-medullary nailing is a technically challenging procedure. In complicated cases it may require prolonged exposure to ionising radiation during fluoroscopy of the fracture site, and when the fracture parts cannot be controlled, undesirable opening of the fracture haematoma is inevitable. We present a technically simple method for stable preoperative reduction of femoral shaft fractures, using a standard fracture table with a mounted external supporting device that can be controlled in both anterior-posterior and lateral planes to eliminate the deforming forces of thigh muscles. Fourteen mid-shaft femoral fractures were reduced by this method prior to intra-medullary nailing. This is an effective method for achieving stable control of a fracture. It is technically easy to perform and should reduce the radiation exposure of the patient and the surgical team to ionising radiation.

Musculoskeletal deformities in Behr syndrome.

SUMMARY: Seventeen children with Behr syndrome were investigated, focusing on the musculoskeletal deformities and long-term outcome. Behr syndrome is characterized by optic atrophy beginning in early childhood associated with ataxia, spasticity, mental retardation, and posterior column sensory loss. The ataxia, spasticity, and muscle contractures, mainly of the hip adductors, hamstrings, and soleus, are progressive and become more prominent in the second decade. In 70% of the patients, contractures developed in the lower limbs, requiring surgery mainly for the Achilles tendon, hamstrings, and adductor longus. At last follow-up at an average age of 21.7 years (range, 8-31 years), 13 of the patients are housebound walkers, 2 are nonfunctional walkers, and 2 are nonwalkers.

Anxiety reaction in children during removal of their plaster cast with a saw.

We have had experience of an 18-month-old boy with a cardiomyopathy who died a few minutes after removal of his cast with a saw, apparently from a malignant cardiac arrhythmia triggered by anxiety. We therefore examined the anxiety reaction to this method of removal of a plaster cast in 20 healthy children; ten were provided with hearing protectors and ten were not. The level of anxiety was assessed by measuring the heart rate, a known physiological indicator of anxiety, before, during and five minutes after removal of the cast. The noise level was also measured. The results showed a mean increase in heart rate during the procedure of 27.9 beats per minute (bpm) (26.9%) in the children with no hearing protectors and 10.4 bpm (11.1%) in children who used hearing protectors (p < 0.001). Five minutes after the procedure the heart rate had returned to the baseline rate in all patients. We recommend that hearing protectors should be used in children undergoing removal of a plaster cast to decrease the anxiety reaction. If possible, clinicians should avoid the use of a saw for this purpose in children with a cardiomyopathy.

Arthrodesis with the Ilizarov device after failed knee arthroplasty.

Thirteen patients with failed total knee arthroplasty (TKA) due to infection (12 patients) or aseptic loosening (1 patient) underwent arthrodesis using the Ilizarov external fixator. Solid fusion was achieved in all patients with an average healing time of 27.6 weeks. Patients spent an average 18.8 weeks in the fixator followed by an average 8.8 weeks in a plaster cylinder cast. Five patients had a pin tract infection and one a superficial wound infection. One patient had 15 degrees recurvatum after surgery that was gradually corrected by adding a hinge system to the fixator. Average shortening of the affected limb was 3.7 cm (range: 1-6 cm). The Ilizarov fixator for knee arthrodesis after failed TKA produced favorable results and should be considered for use by surgeons familiar with the technique.

The increased swelling and instantaneous deformation of osteoarthritic cartilage is highly correlated with collagen degradation.

OBJECTIVE: To provide evidence for the hypothesis that the loss of tensile strength of osteoarthritic (OA) cartilage (resulting in swelling-the hallmark of OA) is due to an impaired collagen network and not to loss or degradation of proteoglycans. METHODS: The amount of degraded collagen molecules, the fixed charge density (FCD) on a dry-weight basis, the degree of swelling in saline, and the instantaneous deformation (ID; a test reflecting the tensile stiffness of the collagen network) were measured in full-depth OA femoral condyle samples. In addition, levels of the crosslink hydroxylysylpyridinoline (HP), the amount of degraded collagen molecules, and the degree of swelling were determined in the 3 zones (surface, middle, and deep) of OA cartilage. We also compared the ID of normal and OA cartilage. RESULTS: In full-depth OA cartilage, a close relationship was found between swelling and ID. Swelling and ID correlated strongly with the amount of degraded collagen molecules, and were not related to FCD. OA cartilage showed the same zonal pattern in HP levels as normal cartilage (i.e., an increase with depth). No relationship was found between collagen crosslinking and swelling of the surface, middle, and deep zones. In all 3 zones, swelling was proportional to the amount of degraded collagen molecules. Compared with that of normal cartilage, the change in ID of OA cartilage was most pronounced at the surface in a direction parallel to the direction of the collagen fibrils. CONCLUSION: The decreased stiffness of the OA collagen network (as measured by swelling and ID) is strongly related to the amount of degraded collagen molecules. The anisotropy in ID parallel and perpendicular to the direction of the fibrils revealed that the impairment of strength resides mainly in, and not between, the fibrils. Proteoglycans play only a minor role in the degeneration of the tensile stiffness of OA cartilage.

[Operative mortality in surgery for hip fractures].

Prevalence of hip fractures is increasing world-wide, as the mean age of populations increases. Despite advances in anesthesia, nursing care, and surgical techniques, hip fractures remain a significant cause of morbidity and mortality in the elderly. We operated on 65 cases of hip fractures from 1995 to the end of 1997: average age was 82.9, 72% were women, average waiting time for operation was 1.6 days, perioperative mortality was 3.5% and postoperative mortality 26.2%.

[Surgery for groin and lower abdominal pain in soccer players].

We treated 57 professional soccer players with groin and lower abdominal pain, 44 of them successfully, using conservative methods and 13 by surgery. Because of its anatomical site, the gracilis muscle is involved in almost all movements of the femur. It therefore is frequently involved in injury due to overuse, especially at its insertion (enthesopathy). In all 13 operated on, the gracilis was cut percutaneously, sometimes as a single procedure and sometimes with concomitant sportsmen's inguinal hernioplasty. All except 1 of those operated on returned to their professional sport activities.

Role of physical activity training in attenuation of height loss through aging.

BACKGROUND: Although the genetic contribution to variability in bone mass has been estimated to be as high as 80%, evidence continues to accumulate suggesting that factors such as physical activity can influence bone mass which may avoid compression of the vertebrae leading to slower stature decline with age. OBJECTIVES: This study examines whether regular exercise has the potential of positively affecting the aging process with regard to height loss. METHODS: The height of 957 females and 1,088 males who were 35-55 years of age in 1965 were measured again in 1995. Based on a questionnaire, the subjects were divided into four groups. Group A (80 females, aged 73. 2 +/- 6 years, and 141 males, aged 72.1 +/- 5.7 years) represented subjects who were engaged in moderate vigorous aerobic activity throughout their lives; group B (95 females, aged 73.6 +/- 5.5 years, and 207 males, aged 71.7 +/- 6.1 years) were subjects who started their moderate vigorous aerobic activity around the age of 40 and kept their activity until the present time; group C (362 females, aged 73.2 +/- 5 years, and 390 males, aged 71.1 +/- 6 years) were persons who were active as young adults, but did not continue to exercise, and group D (425 females, aged 72.8 +/- 5.3 years, and 350 males, aged 70.9 +/- 6.1 years) were subjects who had not exercised regularly throughout their lives. RESULTS: All subjects lost height due to aging. However, significant (p < 0.05) differences in rate of height loss were found among the A, B, C, and D groups: for females 3.4 +/- 0.7, 3.5 +/- 0.8, 6.0 +/- 0.5, and 6.5 +/- 0.7 cm, respectively; for males 2.6 +/- 0.5, 3.1 +/- 0.4, 5.3 +/- 0.4, and 5. 5 +/- 0.5 cm, respectively. In addition, the females' height loss rate was significantly (p < 0.05) higher than that of the males in all four activity categories. CONCLUSIONS: These data suggest that lifelong moderate endurance training, especially after the age of 40 years, is associated with attenuation of height loss in both sexes. However, the magnitude of the attenuation is significantly higher in males.

Left ventricular contractility and function at peak aerobic and anaerobic exercises.

PURPOSE: The present study compared and evaluated left ventricular function and contractility at peak incremental aerobic type exercise and all-out explosive anaerobic effort in young healthy trained subjects. METHODS: Twenty-two young healthy trained subjects (19 +/- 1 yr) were studied by two-dimensional direct M-mode echocardiography at peak aerobic and at peak all-out anaerobic exercises, performed on cycle ergometer. RESULTS: All subjects completed the study without any electrocardiographic abnormalities. Significant (P < 0.05) differences between the aerobic and the anaerobic efforts were noted for peak cardiac output (24 +/- 2.0 and 15.0 +/- 1.1 L x min (-1), respectively), left ventricular pressure-volume ratio (5.8 +/- 0.6 and 4.7 +/- 0.5 respectively), end systolic volume (33 +/- 4 and 42 +/- 5 mL, respectively), ejection fraction (79 +/- 7 and 66 +/- 5%, respectively), and total peripheral resistance (TPR) (367 +/- 90 and 704 +/- 90 dynes x s(-1) x cm(- 5), respectively). CONCLUSIONS: These data suggest that left ventricular at peak all out anaerobic effort differed markedly from those observed at peak aerobic exercise. These differences are presumably due to the different after-load responses between the two exercise modes. Therefore, it is suggested that anaerobic-type effort should be performed with great caution in normal young healthy subjects.

Osteoid osteoma: resection with CT guidance.

BACKGROUND: Osteoid osteoma is a benign bone lesion characterized by nocturnal pain mostly, which may be relieved by non-steroidal prostaglandin inhibitors. Treatment by complete resection of the nidus immediately relieves the pain. Intraoperative location of the nidus may be difficult, and extensive bone resection may be necessary to ensure complete excision. Few studies have described resection of osteoid osteoma under CT guidance, and little attention has been given to lesions near the neurovascular bundle. OBJECTIVE: To report our results of osteoid osteoma resection under CT guidance, with specific attention to lesions lying near the neural structure. METHODS: Nine patients with suspected osteoid osteoma underwent resection with a 6.8 mm core drill under CT guidance. RESULTS: Histologic confirmation was obtained in seven patients, while in two there was no evidence of the nidus in the excised bone material. All nine reported complete pain relief immediately after the surgery. Postoperative CT scan showed complete removal of the osteoid osteoma. CONCLUSIONS: Removal of osteoid osteoma under CT guidance is simple, safe and allows complete removal of the nidus with low morbidity.

Early mobilization after sliding achilles tendon lengthening in children with spastic cerebral palsy.

Equinus deformity is a common finding in children with cerebral palsy and may be treated by Achilles tendon lengthening. To prevent recurrence, some authors recommend immobilizing the operated leg with an above-knee cast for six weeks, followed by use of a night splint or orthosis. Nevertheless, there are recurrence rates of up to 20.5%. The aim of this study was to evaluate the long-term result of postoperative immobilization for two weeks in a below-knee cast and early weight bearing, without the use of a splint or orthosis. Thirty-six children (52 feet) with spastic cerebral palsy underwent sliding Achilles tendon lengthening. Follow-up of five to ten years showed a comparable recurrence rate (19.2%) to that reported with the standard, more stringent management approach. Most of the recurrences were in children operated on before five years of age. We believe earlier motion helps to sustain the tendon length achieved at surgery and allows for earlier independent gait.