Metabolism of proteoglycans in tendon.

Tendons are dense, fibrous connective tissues that are responsible for transmitting mechanical forces from skeletal muscle to bone. From a clinical perspective, tendinopathy (defined as a syndrome of tendon pain, tenderness and swelling that affects function) is very common, both within the sporting arena and in the workplace. Importantly, proteoglycans are essential components of the tendon extracellular matrix (ECM) and changes in their expression and metabolism/turnover have been associated with tendinopathy. Within tendons, the small leucine-rich proteoglycans (SLPRs), decorin, fibromodulin, lumican and keratocan predominate within tensional regions, while in tendon fibrocartilage, increased concentrations of proteoglycans common to the articular cartilage phenotype are present, including aggrecan, biglycan and proteoglycan 4. However, the rate of proteoglycan turnover within tendon is markedly higher than that of cartilage, mediated via the "aggrecanases," which are constitutively active in the tendon matrix. Data suggest that this increased proteoglycan turnover is likely to be required to maintain normal tendon homeostasis, with perturbations in proteoglycan metabolism contributing to tissue dysfunction. Thus, future studies aimed at furthering our fundamental knowledge of tendon proteoglycan metabolism in health and disease are important in the development of improved treatments for tendon disorders.

How accurate is partial weightbearing?

The accuracy of partial weightbearing was assessed in six healthy volunteers and 23 patients who had sustained either a fracture of a lower limb or surgery. They were trained to weightbear partially using the conventional bathroom scale method and were assessed in a gait laboratory using force platforms. The amount of weight exerted on the involved limb during three-point crutch walking was determined. Four of six volunteers exerted a mean of 27% of body weight more than required. The remaining two volunteers exerted a mean of 8.5% of body weight less than required. Of the 23 patients, 21 exerted a mean of 35.3% of body weight more than that prescribed and two patients exerted a mean of 11.97% of body weight less than that prescribed. In both groups there was little relationship between the weightbearing prescribed and actual weightbearing. None of the patients or volunteers was able to reproduce the extent of partial weightbearing for which they were trained using the bathroom scale method, confirming that this technique of instructing patients in partial weightbearing is inaccurate.

Catabolism of aggrecan, decorin and biglycan in tendon.

We have examined the catabolism of the proteoglycans aggrecan, decorin and biglycan in fresh tendon samples and in explant cultures of tissue from the tensional and compressed regions of young and mature bovine tendons. A panel of well-characterized antibodies that recognize glycosaminoglycan or protein (linear or neoepitope) sequences was used to detect proteoglycans and proteoglycan degradation products that were both retained within the tissue and released into the culture medium. In addition, a reverse-transcriptase-mediated PCR analysis was used to examine the mRNA expression patterns of tendon proteoglycans and aggrecanases. The results of this study indicate a major role for aggrecanase(s) in the catabolism of aggrecan in bovine tendon. The study also provides a characterization of glycosaminoglycan epitopes associated with the proteoglycans of tendon, illustrating age-related changes in the isomers of chondroitin sulphate disaccharides that remain attached to the core protein glycosaminoglycan linkage region after digestion with chondroitinase ABC. Evidence for a rapid turnover of the small proteoglycans decorin and biglycan was also observed, indicating additional molecular pathways that might compromise the integrity of the collagen matrix and potentially contribute to tendon dysfunction after injury and during disease.

MRI in the management of tibial plateau fractures.

Twenty-one consecutive patients with fractures of the tibial plateau were investigated by standard radiography and magnetic resonance imaging (MRI) before treatment. It was found that MRI was more accurate in determining the classification of the fracture, in the identification of previously 'occult' fracture lines, and in accurate measurement of displacement and depression of fragments. This resulted in a change in the classification of 10 fractures (47.6 per cent) and so a change in the management of four patients (19 per cent). In addition, MRI permits the reliable identification of associated intra- and periarticular soft tissue injuries pre-operatively for the first time in this group of injuries, seen to be present in 47.6 per cent of this series. This is higher than previously reported. No problems were encountered with the imaging technique, and in view of the significant effect on patient management, the authors now consider it to be the imaging method of choice.

Revision of failed total elbow arthroplasty.

We reviewed 25 patients with rheumatoid arthritis who had failure of 26 primary total elbow arthroplasties causing pain and loss of function. Most revision cases required special custom implants to treat varying bone loss and soft-tissue disruption. Assessment showed satisfactory functional results in the patients treated by revision at a mean follow-up period of 35 months. Our review suggests that revision surgery produces short- to medium-term painfree function, and is the treatment of choice for a failed total elbow arthroplasty in the absence of infection.

Arthroscopic ankle arthrodesis.

We performed arthrodesis of the ankle in eight patients by arthroscopic joint excision and fixation with crossed tibiotalar compression screws. Two patients had rheumatoid arthritis and six had post-traumatic osteoarthritis. None had a serious deformity of the ankle. Clinical ankylosis was achieved in all cases and there was radiological evidence of bone fusion in four.

Recurrent dislocation of the hip in adult paraplegics.

Recurrent dislocation of the hip is rare and has not previously been reported in adult paraplegics. This paper describes 3 cases. In one patient it was spontaneous, occurring 16 years after the original injury and was associated with a flexion-adduction contracture of the hip and a shallow acetabulum. One case occurred after minor trauma in a patient who experienced flexion-adduction spasms of the hip. In the third patient the condition was secondary to posterior acetabular deficiency following a conservatively treated fracture dislocation. All 3 patients experienced symptoms of disabling autonomic dysreflexia during the episodes of dislocation. The importance of recognising and adequately treating hip injuries in patients presenting with paraplegia secondary to spinal cord injury is stressed. In patients with spastic paraplegia presenting with recurrent dislocation of the hip, operative treatment combining a soft tissue repair and a bone block to augment the acetabulum is recommended.

Dillwyn Evans operation for relapsed club foot. Long-term results.

We reviewed the long-term results of the Dillwyn Evans procedure for club foot in 60 feet of 45 patients with an average age of 29 years, using four different scoring systems. The results at 12 to 38 years were compared with those of an earlier study of the same group of patients. Function was satisfactory in 68% of feet; 90% of the patients were able to perform all desired activities. Mild residual deformity was compatible with satisfactory function, and poor function was related to ankle and subtalar stiffness. Our results suggest that this procedure has a low rate of deterioration and degenerative change with time.

Preparation of skin for surgery.

A survey of 113 hospitals in the UK was performed to assess current practices regarding skin preparation for surgery. The findings of the survey are presented and where relevant compared with a similar survey conducted in 1983. It was found that, despite scientific evidence supporting change, traditional practices still dominate. This evidence is discussed and, based on this, some changes in practice are suggested.

Comparison of clinical tests and the KT1000 in the diagnosis of anterior cruciate ligament rupture.

A prospective study was undertaken to compare the accuracy of the Lachman test, anterior drawer test and jerk test with the KT1000 knee arthrometer in patients with proven anterior cruciate ligament deficiency. The Lachman and anterior drawer tests were found to be the most accurate indicators of anterior cruciate ligament deficiency. The KT1000 knee arthrometer was found to be totally inaccurate, which precludes its use as an objective measure of anteroposterior laxity of the knee.

A solution for arthroscope misting.

A prospective study was undertaken to compare the incidence of arthroscope eyepiece misting in two groups of patients. In one group the irrigation fluid was at room temperature and in the other group the fluid was warmed to body temperature. Arthroscope eyepiece misting was eliminated when irrigation fluid at body temperature was used.

Radiological sign of chronic anterior cruciate ligament deficiency.

An early radiological sign of anterior cruciate ligament deficiency is described. A retrospective study of the radiographs of 38 patients with chronic anterior cruciate ligament deficiency was performed. In 36 patients from this group an osteophyte was present on the medial femoral condyle adjacent to the medial tibial spine. This was best seen on a 30 degree notch view and was the earliest radiographic sign of chronic anterior cruciate ligament deficiency.

Effect of delay in processing on lysis-centrifugation blood culture results from marrow transplant patients.

The effect of delay in processing on results of lysis-centrifugation (LC; Isolator) blood cultures was assessed in 4,577 paired blood specimens. Blood specimens were obtained at all hours from 384 febrile marrow transplant patients with indwelling venous catheters and were processed by the LC technique and by a conventional two-bottle method. Most patients (84%) were receiving broad-spectrum antibiotics at the time of blood culture. Specimens were delivered to the laboratory, where Isolator tubes were held at 35 degrees C and processed in batches between 0700 and 1730 h daily. This procedure resulted in a delay beyond the manufacturer-suggested processing time of less than 8 h for 1,853 (42%) of the LC cultures. There was no overall difference in the recovery of organisms present in LC cultures processed after being held for 8 to 24 h compared with the conventional two-bottle method. LC methodology had shorter time to detection than the conventional method for detection of Candida spp. and Pseudomonas spp. (P less than 0.05). However, time to detection for Streptococcus spp. and members of the family Enterobacteriaceae, responsible for 16.3% of total isolates, was prolonged significantly by delay in processing when compared with the conventional two-bottle method (P less than 0.01). Results of this study support the recommendation of the manufacturer for processing of Isolator tubes within 8 h or less. Although one can safely delay processing beyond 8 h in terms of total recovery of organisms, such delays were associated with longer time to detection for certain important potentially pathogenic organisms which accounted for a sizeable proportion of blood culture isolates from marrow transplant patients.