In vivo gastrocnemius muscle fascicle length in children with and without diplegic cerebral palsy.

The effect of spastic cerebral palsy on in vivo gastrocnemius muscle fascicle length is not clear. Similarity of fascicle lengths in children with diplegia and typically developing children, but shortening of fascicle lengths in the paretic legs of children with hemiplegia compared with the non-paretic legs, are both reported. In the former case, comparisons were made between fascicle lengths normalized to leg length, whereas in the latter case, absolute fascicle lengths were compared. The inherent assumptions when normalizing fascicle length (measured via ultrasonography) were not validated, raising the possibility that inappropriate normalization contributed to the controversy. We used statistical methods to control the potential confounding effect of leg length on fascicle length, and tested the feasibility of the normalization method for a group of 18 children with diplegia (nine males, nine females; mean age 8y 7mo [SD 3y 11mo], range 2-15y; Gross Motor Function Classification System levels II and III) and 50 typically developing children (20 males, 30 females; mean age 9y 1mo [SD 2y 4mo], range 4-14y). Children with diplegia, as a group, had shorter absolute and normalized fascicle lengths (p<0.05) but we could not refute the appropriateness of the normalization method. Other methodological issues (such as sample characteristics) might have contributed to the apparent controversy between the studies.

Orthopaedic referrals from a cardiothoracic transplant population.

In this study we audited the orthopaedic referrals from the cardiothoracic transplant population at Wythenshawe Hospital, South Manchester. A total of 33 referrals in 29 patients were made during the period of study. The referrals represented 10.3% (33/321) of the transplant population. However, the rate of referral per postoperative year was 37.9/1000, which was of a similar order to that of the general population. The diagnosis at referral was activity related in 24 (72.7%) referrals, with one-half of these being related to some form of sporting activity. Complications of immunosuppression may have contributed in up to 15 (45.4%) of referrals. We believe that musculoskeletal problems after cardiothoracic transplantation do not place an excessive burden on our orthopaedic department and that the pattern of referrals indicates that the transplant programme is a success.

Spinal osteomyelitis presenting with a life-threatening pleural empyema.

STUDY DESIGN: This case report illustrates a rare presentation of spinal osteomyelitis that initially manifested as a life-threatening pleural empyema leading to misdiagnosis. OBJECTIVES: A high index of suspicion is required to make the correct diagnosis of spinal osteomyelitis, especially with unusual presentations. Appropriate antibiotic management should be commenced immediately the diagnosis is made. SUMMARY OF BACKGROUND DATA: A review of the literature reveals five previous cases of vertebral osteomyelitis associated with pleural effusions. In three of these, the effusions were reactive and sterile. There is only one previous case of a pleural empyema related to primary spinal osteomyelitis. There also is one case report of vertebral osteomyelitis presenting as a mediastinal abscess. METHODS: A case is presented of a man thought to have bronchogenic carcinoma with a destructive vertebral metastasis who was sent for palliative radiation therapy. A life-threatening pleural effusion subsequently developed, and after additional investigation, he was found to have spinal osteomyelitis with a pleural empyema. RESULTS: The empyema was drained through an indwelling chest tube, and the patient was administered appropriate antibiotics. He made a complete and uneventful recovery. CONCLUSIONS: The case illustrates a rare presentation of spinal osteomyelitis. It exemplifies the dictum that if a malignant disease is suspected, every effort has to be made to establish a histologic diagnosis to prevent inappropriate management and the potentially devastating consequences of an incorrect diagnosis. It also high-lights the difficulties in diagnosis of vertebral osteomyelitis with empyema. With correct management, the prognosis is excellent.

The relationship of increased capillary filtration and bone formation.

The effect of functional activity on bone formation and interstitial fluid space in a standardized tibial defect was measured in 19 dogs with one hind limb elevated and the other weight bearing and in 15 dogs bearing weight on all four legs. The interstitial fluid space (V(isf)) of the woven bone of the weight-bearing defect was larger than that in the elevated legs at seven and 14 days. By 28 days, this difference disappeared. In a third group of six dogs, medullary canal pressure was measured in the immobilized and weight-bearing tibias. The pressures were higher in the weight-bearing tibiae at two, three, four, and five days. Because the increase in V(isf) in the weight-bearing defects coincided with the onset of woven bone formation in the defects and an increase in medullary canal pressure, an increase in venous pressure could increase capillary pressure and capillary filtration. Such an increase in filtration might cause the larger V(isf) in the weight-bearing defects and better capillary perfusion of precursor cells of the osteoblast. A hypothesis is that increased fluid flow from increased capillary filtration might produce streaming potentials, a possible signal for increased cellular activity.

Isolated tuberculosis of a skeletal muscle.

A case is described of tuberculosis in the muscle belly of abductor pollicis longus in a 25-year-old Asian woman. The complaint was of swelling and, as there was no evidence of tuberculosis elsewhere, the diagnosis was not made until the lump was explored surgically.

Effect of weight-bearing on healing of cortical defects in the canine tibia.

UNLABELLED: It has been generally accepted that mechanical stimulation is an important factor in the promotion of formation of bone. Fracture-healing consists of periosteal bridging of the fracture, which achieves stability, and proliferation of endosteal bone to fill the defects between the ends of the bone. To evaluate the effect of weight-bearing on bone-healing, an operatively created defect in the tibial cortex was chosen as an experimental model. In one set of dogs (Group 1), a bilateral defect in the tibial cortex was created and weight-bearing was permitted on one tibia but not on the opposite one. In Group 2, a bilateral defect in the tibial cortex was made and weight-bearing was allowed on both tibiae. A third group of dogs of similar age (Group 3) had no tibial defects. Quantitative histomorphometry was used to measure formation and porosity of bone. Weight-bearing was measured with both static and dynamic techniques. Significantly less woven bone formed in the defects in the non-weight-bearing tibiae than in the weight-bearing tibiae. This appeared to be due to a disuse response in the underloaded tibiae, in which less bone formed, rather than to the formation of more bone in the weight-bearing tibiae. The data suggest that weight-bearing is a permissive factor, not a stimulus, for formation of woven bone in a tibial defect. CLINICAL RELEVANCE: This animal model supports the concept that lack of weight-bearing decreases the amount of woven bone that is formed in a healing tibial defect. The results of this study indicate that weight-bearing increases the formation of bone in fracture-healing.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of displaced subcapital fractures with the Charnley-Hastings hemiarthroplasty.

Between December 1982 and June 1986, 98 displaced subcapital femoral neck fractures were treated using the Charnley-Hastings bipolar hemiarthroplasty. Although the patients were elderly, often with associated medical problems, the operation was well tolerated and the mortality at one and six months was 14.4% and 24.5% respectively. Fifty-four hips were reviewed after an average follow-up of 33 months; 64.8% of patients had a good or excellent result. The fair or poor results were seen mainly in patients with poor pre-operative mobility and multiple medical problems. A significant cause of morbidity was dislocation (two interprosthetic) which occurred in six hips. There were two cases of deep sepsis but neither patient was fit for further surgery. There were no cases of acetabular erosion requiring revision surgery.

Parathyroid hormone effects on skeletal exchangeable calcium and bone blood flow.

The effects of alterations in serum calcium levels on the volume of distribution of a calcium tracer in bone and on bone blood flow were investigated in dogs by manipulation of parathyroid status. The volume of distribution increases with increasing serum calcium. This implies that there is a concentration-dependent binding mechanism in the extravascular space of bone, which is not saturated at the levels of serum calcium achieved in these experiments. The skeletal exchangeable calcium was increased in hypercalcemic dogs and decreased in hypocalcemic dogs. Cancellous bone contains proportionately more exchangeable calcium than cortical bone. Bone blood flow was decreased by 50% 15 min after injection of a bolus of parathyroid hormone (PTH) but returned to control values by 240 min. Fifty-two hours after the induction of hypercalcemia with repeated doses of PTH, there was no difference in blood flow over control animals.

Cortical and cancellous bone: age-related changes in morphologic features, fluid spaces, and calcium homeostasis in dogs.

The changes in cortical and cancellous bone that occur with aging were studied by measuring morphologic and physiologic variables for both types of bone in dogs. The percentage area of cortical and cancellous bone, rate of bone formation, vascular volume, bone water, and volume of distribution of calcium tracer all showed statistically significant changes at the time of bone maturity. Canine cortical bone cell volume progressively decreased with advancing age, and cancellous bone cell volume significantly decreased between adult and old dogs. The volume of distribution technique can be used to determine the relative contributions of cortical and cancellous bone to the total body exchangeable calcium ion pool.

A radiological assessment of interprosthetic movement in the Charnley-Hastings hemiarthroplasty.

Forty-six patients with acute displaced subcapital fractures of the femur were treated between December 1982 and December 1984 with Charnley-Hastings bipolar prostheses. The interprosthetic movement in 23 patients was assessed radiologically at least 1 year after surgery. Four patients (17.4 per cent) had no interprosthetic movement in abduction but the remainder (82.6 per cent) had some movement, although only 3 patients (13 per cent) had more than 5 degrees of abduction within the prosthesis.