Biomedical subjects
Publications and source records attributed to G Bentley.
A prospective study of 120 consecutive total hip replacements showed that deep suction drains produced maximal drainage volumes in the first 24 hours. Their continued presence resulted in minimal further drainage, did not reduce the likelihood of haematoma formation and led in some cases to the spread of skin organisms into the wound.
A new staining technique based on alcian blue and hematoxylin was used during the study of experimentally produced fractures in long bone. The distinction between cartilage, woven bone, mature bone and necrotic bone during successive stages of the fracture healing process was particularly remarkable. This method was found also to be very useful in the study of general tissue morphology. It is suggested that this postdecalcification light microscopy staining method is suitable for studies of cartilage and bone development with particular reference to ossification, remodelling and bone pathology.
Biochemical, morphometric and electron histochemical methods have failed to demonstrate the presence in tendon of keratan sulphate, a common component of connective tissue proteoglycans. Using a monoclonal antibody specific for keratan sulphate, a positive localization of this molecule was made in the gastrocnemius tendon of stage 44 chicken embryos both at the light and electron microscopical levels.
Because of the difficulty of assessing prognosis, a clinical and radiological review of 103 injuries of growth plates was performed. Thirteen patients showed retardation of growth and in 4 it was clinically obvious. In addition, external deformity occurred because of failure of remodelling in 1 case. In 9 cases there appeared to be slight stimulation of growth. The correlation between the Salter-Harris classification and retardation of growth was not always clear, especially in Salter-Harris type IV injuries, wherein prognosis varied with site. At the distal end of the tibia two groups of type IV injury were identified having respectively a 0 and 62.5 per cent incidence of retardation of growth. A new classification of distal injuries of the tibia is proposed, with superior predictive value for retardation of growth than that of Salter and Harris. This is valuable as a guide to prognosis and may facilitate treatment.
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Both intrinsic and extrinsic factors are known to be involved in the morphogenesis of diarthrodial joints. The use of specific antibodies to collagens I and II and keratan-sulphate-containing proteoglycans (KSPG) has enabled the distributions of these macromolecules to be followed during the development of the third metatarsophalangeal joint in the chicken embryo. Our study shows that cartilage differentiation occurs as a continuous rod, which is then subsequently divided into separate elements. Further development also reveals that, unlike the matrix of the cartilaginous elements, there is a differential distribution of collagen (type II) and KSPG in the presumptive joint region. It is proposed that a decrease in KSPG in the presumptive joint region at stages 28/30 may be involved in the mechanism for the flattening of cells in formation of the interzone. Whereas, a decrease in collagen across the joint interzone region may provide an area of weakness, which might allow forces produced by the developing musculature to cause cavitation.
The transcutaneous oxygen monitor was developed as a non-invasive method of measuring arterial oxygen tension in neonates and has since been applied to adults as a method of assessing circulatory impairment due to peripheral vascular disease. Transcutaneous oxygen pressure measurements (tcPO2) were taken daily on normal volunteers for a period of three weeks to determine the reproducibility of tcPO2 measurements. Results varied by an average of almost 10% from the mean for each individual. This variation was not clinically significant since the variation did not result in readings below 35-40 mmHg, this being the level which reflects severe skin ischaemia. The correlation between simultaneous chest and leg readings was not sufficient to recommend this ratio as an accurate index of vascular insufficiency.
Allografts of intact cartilage, isolated chondrocytes and cultured chondrocytes taken from the epiphysial growth-plate and from the articular surface of immature rabbits were inserted into full thickness defects in the tibial articular surface of 160 mature rabbits. In the contralateral knees, which were used as controls, similar defects were made but no grafts were inserted. Grafts were followed up for periods of up to one year after transplantation. Both intact articular and intact growth-plate grafts produced significantly better repair than that seen in control ungrafted defects in normal joints (P less than 0.01 and P less than 0.05 respectively) and in arthritic joints (P less than 0.01). Cultured chondrocytes cut to a precise fit also produced significantly better repair than ungrafted defects in arthritic joints (P less than 0.05).
Minor degrees of malalignment of the patella and anatomical abnormalities including a flattened sulcus angle and an increased ratio between patellar tendon length and patellar length (PT:P) have been suggested as predisposing factors in the causation of chondromalacia patellae, as well as patellar instability. In order to confirm or refute this hypothesis a prospective study has been performed comparing the congruence and sulcus angles and the PT:P ratio in a group of 35 patients with chondromalacia confirmed by arthroscopy and a group of 33 patients with instability, with those of a group of 50 knees in normal volunteers. While there was a statistically significant correlation between an increased sulcus and congruence angle and a high-riding patella in patients with instability, no correlation could be identified in patients with idiopathic chondromalacia.
Experimentally produced fractures in long bones studied by light and electron microscopic histochemistry were found to heal by a process of enchondral calcification. There was intense proliferation in the cells of the cambium layer of the periosteum, with differentiation to chondroblasts and osteoblasts, suggesting that this layer was the primary tissue responsible for development of the callus. Cytoplasmic processes of the hypertrophic chondrocytes appeared to bud and produce matrix vesicles. Alkaline phosphatase activity was detected along the plasma membrane of the hypertrophic chondrocytes and around the matrix vesicles, before any signs of mineral deposition. Calcification took place by deposition of hydroxyapatite crystals in and around these matrix vesicles which frequently showed alkaline phosphatase activity. It is suggested that there is a close functional association between alkaline phosphatase activity and calcification in the process of fracture healing, which is another type of enchondral calcification mediated by matrix vesicles.
Computerised tomography of the lumbar spine was performed on 22 patients with clinical evidence of prolapse of an intervertebral disc and normal or equivocal radiculograms. Of 11 patients with positive scans who had an operation the presence of pathology was confirmed in 10. Although CT scanning is always helpful in diagnosing disc disorders, where facilities are scarce (as in Great Britain) it is best employed in patients with negative or non-contributory radiculography.
Arthritis in the elderly can be very effectively treated by a combination of careful orthopaedic and rheumatological assessment. The overall functional assessment, and definition of the aims and likely results of surgical treatment by the team approach, involving occupational therapists, physiotherapists and social workers, are important for success. There are many worthwhile surgical procedures available to relieve pain, and restore mobility and independence to those affected by osteoarthritis and rheumatoid arthritis.
The records of 340 patients with a clinical diagnosis of tennis elbow were surveyed and the results of conservative treatment assessed. Of 157 patients successfully treated by local steroid injections, 92% achieved their good result after one or two injections. Repeated injections were not helpful. Simple lateral release of the common extensor origin was carried out on 42 elbows in 37 patients. Thirty-seven elbows in 32 patients were personally reviewed. Satisfactory pain relief was achieved in 33 elbows (89%). There were no significant complications.
Full thickness samples of articular cartilage were removed from areas of chondromalacia on the medial and "odd" facets of the patellae of 21 adults and examined by histology, autoradiography and electron microscopy. Surface fibrillation, loss of superficial matrix staining and reduced 35SO4 labelling was seen, with little change in the deep zone. Ten cases showed "fibrous metaplasia" of the superficial cartilage with definite evidence of cell division and apparent smoothing of the surface. Scattered chondrocyte replication appeared to occur in the surrounding intact cartilage. The findings suggest that early lesions in chondromalacia patellae may heal either by cartilage or fibrous metaplasia and that this may account for the resolution of clinical symptoms.
The results of treatment in 77 clubfeet were assessed after an average follow-up of 8 years. In those patients with surgical treatment it was found that the Turco posteromedial release within the first 3 months of life resulted in 13 of 16 satisfactory feet. In comparison, only five of 21 feet had satisfactory results when the average age of operation was delayed to 3.7 years and a less extensive release performed. At follow-up, abnormal radiological findings were not found in the early operated cases. The average talocalcaneal index was 47 degrees. The late operated feet showed major abnormal X-ray film findings, and their average index was 38 degrees. Good functional results, however, often coexisted with abnormal radiological findings in the midfoot. Abnormal findings of the hindfoot were always associated with unsatisfactory results. We conclude that the use of early (3 months) Turco posteromedial release can offer excellent results in treating severe resistant clubfeet.
We used a modification of the wake-up test to monitor spinal cord function in 102 consecutive scoliotic patients undergoing Harrington instrumentation. Four patients were found to have a neural deficit when they were awakened during the operation. Three recovered immediately after partial release of the distracting force; one required immediate removal of the rod and was left with a slight neural deficit. Using our method, we have encountered no problem in performing the wake-up test, although attention is drawn to the difficulty in repeating the test if the patient is re-anaesthetised with diazepam. There were no false negative results in this series.
Chondromalacia patellae is a distinct clinical entity characterized by retropatellar pain that is associated with recognizable changes in the articular cartilage of the posterior surface of the patella. Several factors may be involved in the etiology, such as severe patella alta, trauma, and, in rare cases, abnormal patellar tracking. Clinical symptoms and signs are reliable in only 50% of cases, but measurable quadriceps wasting, palpable patellofemoral crepitus, and effusion are strongly suggestive. Diagnosis must be confirmed by arthroscopy or direct examination of the posterior surface of the patella. Radiologic measurements of patellofemoral relations are of limited value in diagnosis. The initial pathologic finding is usually surface cartilage breakdown. Radioisotope studies show cartilage cell replication which suggests a healing capacity in early cases following treatment that alters the load through the affected cartilage. There is no evidence of progression to patellofemoral osteoarthritis, which is probably a different entity. The treatment should be conservative where possible with isometric quadriceps exercises and simple anti-inflammatory drugs such as aspirin. Operative treatment is indicated for patients with persistent pain and macroscopic involvement of more than half a centimeter of the articular cartilage surface. The simplest effective procedure that avoids quadriceps dysfunction and fibrosis is a distal patellar tendon medial realignment with lateral release and medial reefing of the quadriceps expansion. Patellectomy is indicated in more extensive involvement of the patella of 2 or more centimeters in diameter, but this must be performed only when the patient has excellent quadriceps function before surgery and is motivated to exercise after surgery.
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