We prospectively audited 79 patients undergoing primary knee or hip arthroplasty (38 knees, 41 hips) and found that 66% (58% of knees, 73% of hips) had at least one unit of blood transfused postoperatively, with a mean transfusion requirement of 1.3 units per patient (1.1 for knees, 0 to 6; 1.5 for hips, 0 to 4).

We then established a new protocol for postoperative blood transfusion. This requires the calculation of the maximum allowable blood loss (MABL) that each individual patient can safely lose based upon their weight and preoperative haematocrit. The total blood loss up to this volume is replaced with colloid. When a patient’s total blood loss reaches their MABL their haematocrit is measured at the bedside using the Microspin system (Bayer plc, Newbury, UK). If their haematocrit is low (< 0.30 for men, < 0.27 for women), blood is transfused. As a safety net all patients have their haemoglobin formally checked on days 1, 2, and 3 after surgery and have a transfusion if the haemoglobin levels are less than 8.5 g/dl.

We conducted a further audit of 82 patients (35 knees, 47 hips) after the introduction of this protocol. Under the new protocol only 24% of patients required blood (11% of knees, 34% of hips) with a mean transfusion requirement of 0.56 units per patient (0.26 for knees, 0 to 4; 0.79 for hips, 0 to 4).

The use of clinical audit and the introduction of strict guidelines for transfusion can change transfusion practice and result in improved patient care. Our transfusion protocol is a simple and effective method of keeping transfusion to a minimum and is particularly useful in departments which do not have the facility to use autologous blood or reinfusion drains for elective orthopaedic surgery.

We randomly allocated 50 total knee replacements to scrub teams wearing body-exhaust suits (BES) or Rotecno occlusive clothing. The effectiveness of the clothing was assessed using air and wound bacterial counts.

Bacteria were recovered from 62% of wounds (64% BES, 60% Rotecno). The mean air count was 0.5 CFU/ m³ with BES and 1.0 CFU/m³ with Rotecno (p = 0.014). The mean wound counts were 14 bacteria/wound with BES and eight bacteria/wound with Rotecno (p = 0.171). There was no correlation between the air and wound counts (r = −0.011, Spearman’s).

The higher air counts suggest that Rotecno occlusive clothing is less effective than BES, but wounds were equally contaminated with both types of clothing suggesting that at very low levels of air contamination the contribution of bacteria to the wound from the air is irrelevant. Even doubling the air counts from 0.5 to 1.0 CFU/m³ had no detectable effect on the wound.

This allows a reassessment to be made of other sources of contamination the effect of which would previously have been overwhelmed by contamination from air.

We have investigated in a prospective, randomised placebo-controlled study the effect of high-dose aprotinin on blood loss in patients admitted for major surgery (revision arthroplasty of the hip or knee, or for resection of a soft-tissue sarcoma). The mean intraoperative blood loss was reduced from 1957 ml in the control group to 736 ml in the aprotinin group (p = 0.002). The mean requirement for intraoperative homologous blood transfusion in the aprotinin group was 1.4 units (95% CI 0.2 to 2.7) and 3.1 units (95% CI 1.7 to 4.6) in the control group (p = 0.033). The mean length of hospital stay was reduced from 27.8 days in the control group to 17.6 days in the aprotinin group which was not statistically significant.

The intraoperative use of aprotinin in major orthopaedic operations significantly reduced blood loss and the required amount of packed cells. It may result in a decrease in the length of hospital stay and costs.

Smoking is an important risk factor for the development of postoperative pulmonary complications after major surgical procedures. We studied 811 consecutive patients who had undergone hip or knee arthroplasty, recording current smoking and drinking habits, any history of chronic disease and such intraoperative factors as the type of anaesthesia and the type and duration of surgery. We recorded any postoperative complications occurring before discharge from hospital. There were 232 smokers (28.6%) and 579 non-smokers.

We found that smoking was the single most important risk factor for the development of postoperative complications, particularly those relating to wound healing, cardiopulmonary complications, and the requirement of postoperative intensive care. A delay in discharge from hospital was usual for those suffering a complication. In those patients requiring prolonged hospitalisation (> 15 days) the proportion of smokers with wound complications was twice that of non-smokers.

When amputation just below the knee becomes necessary after extensive loss of bone from the tibia and of anterior soft tissue in the treatment of tumours, fractures or infection, the remaining proximal tibia may be too short for a below-knee prosthesis, although the knee may be normal. We have included the distal tibia or foot in a long posterior flap by turning it up thus increasing the length of a very short proximal tibial stump. The knee is thereby saved, allowing satisfactory use of a below-knee prosthesis.

This technique is particularly applicable when the distal leg is normal and well vascularised. Five procedures have been undertaken. We present two illustrative cases.

In patients who underwent autogenous iliac bone grafting we studied prospectively injury to the lateral femoral cutaneous nerve (LFCN) in relation to the size (length, depth, width) of the graft. We also examined the neurological deficit, by questioning them about numbness and/or pain in the lateral thigh.

The risk of injury was significantly higher in those in whom the depth of the graft was more than 30 mm. With regard to the length of the graft the incidence of nerve injury was 20% when the graft was 45 mm long or more, 16% when it was between 30 mm and 45 mm long, and 8% when it was less than 30 mm long. We should inform patients of the possibility of such injury, and take size into consideration when harvesting grafts from the ilium.

We performed a prospective, blind, controlled study on wound infection after implant surgery involving 41 procedures in patients infected with the human immunodeficiency virus (HIV) and 141 in HIV-negative patients. The patients were staged clinically and the CD4 cell count determined. Wound infection was assessed using the asepsis wound score. A risk category was allocated to account for presurgical contamination.

In HIV-positive patients, with no preoperative contamination, the incidence of wound infection (3.5%) was comparable with that of the HIV-negative group (5%; p = 0.396). The CD4 cell count did not affect the incidence of infection (r = 0.16). When there was preoperative contamination, the incidence of infection in HIV-positive patients increased markedly (42%) compared with that in HIV-negative patients (11%; p = 0.084).

Our results show that when no contamination has occurred implant surgery may be undertaken safely in HIV-positive patients.

We describe the development and validation of a scoring system for auditing orthopaedic surgery. It is a minor modification of the POSSUM scoring system widely used in general surgery. The orthopaedic POSSUM system which we have developed gives predictions for mortality and morbidity which correlate well with the observed rates in a sample of 2326 orthopaedic operations over a period of 12 months.

Controversy surrounds the aetiology of obstetric brachial plexus lesions. Most authors consider that it is caused by traction or compression of the brachial plexus during delivery. Some patients, however, present without a history of major traction during delivery, and some delivered by Caesarean section also suffer the injury.

In our series of 42 infants, 28 had an Erb’s palsy, and the remaining 14 presented with a more extensive lesion, involving the lower roots. In five of these, a complete ossified cervical rib was found.

We believe that anatomical variations, such as cervical ribs or fibrous bands, can cause narrowing of the supracostoclavicular space, and render the adjacent nerves more susceptible to external trauma.

Patient warming systems are used routinely to prevent hypothermia under anaesthesia. Airflow from warming blankets may potentially influence bacterial counts either by pumping ‘dirty air’ from floor level to the operating area or by blowing the patients’ skin cells into the operating field from airflow under the blanket. Using slit-air sampling we analysed the air quality within a laminar-flow theatre at a simulated operating site. We assessed the effect of ‘high shedding of skin’ under the blanket using volunteer patients with psoriasis. We also simulated general theatre activity outside the laminar-flow area in order to determine whether the bacterial counts in the operating field were affected.

No colonies were grown in any of the groups tested and our results suggest that the patient warming system does not influence bacterial counts at the operating site in an ultraclean air-ventilated theatre, even with patients who have high shedding of skin cells.

Using a scintigraphic technique based on anautologous injection of ^99mTc-labelled erythrocytes, we have evaluated the efficiency of different exsanguination procedures in the upper limb of ten healthy male volunteers. The methods were elevation alone, the use of the Esmarch bandage or a gauze bandage, the Pomidor roll-cuff, the squeeze method and the Urias bag.

The various procedures gave the following median percentage reductions of blood volumes: elevation for 5 seconds 44%, 15 seconds 45%, 30 seconds 46%, 60 seconds 46% and 4 minutes 42%, the Esmarch bandage 69%, a gauze bandage 63%, the Pomidor roll-cuff 66%, the squeeze method 53%, and the Urias bag 57%. With regard to elevation alone no significant differences were found. All the external methods were significantly more effective than elevation alone. Overall, the squeeze method was found to be the best method of exsanguination before inflation of a tourniquet, because it is effective, fast, practical and inexpensive.

Templates are used in the preoperative planning of many orthopaedic procedures. The magnification of the bones on preoperative radiographs can vary despite using standardised radiological techniques. Templates will give misleading measurements unless this magnification is quantified.

A coin may be used to calculate the magnification, with significant improvement in the accuracy of templating (p = 0.05). A group of patients undergoing uncemented arthroplasty of the hip was at high risk for intraoperative fracture of the femur because the magnification of the radiograph was larger than that of the template.

We prospectively studied the use of intercostal EMG monitoring as an indicator of the accuracy of the placement of pedicle screws in the thoracic spine.

We investigated 95 thoracic pedicles in 17 patients. Before insertion of the screw, the surgeon recorded his assessment of the integrity of the pedicle track. We then stimulated the track using a K-wire pedicle probe connected to a constant current stimulator. A compound muscle action potential (CMAP) was recorded from the appropriate intercostal or abdominal muscles. Postoperative CT was performed to establish the position of the screw. The stimulus intensity required to evoke a muscle response was correlated with the position of the screw on the CT scan.

There were eight unrecognised breaches of the pedicle. Using 7.0 mA as a threshold, the sensitivity of EMG was 0.50 in detecting a breached pedicle and the specificity was 0.83.

Thoracic pedicle screws were accurately placed in more than 90% of patients. EMG monitoring did not significantly improve the reliability of placement of the screw.

Hydatid disease of bone is rare. It probably represents between 0.5% and 4% of all human shydatid disease and, in about 60% of patients, affects the spine or pelvis. Between 1986 and 1998, we treated 15 cases of bone hydatidosis. Curettage, swabbing with povidone iodine and filling the defect with polymethylmethacrylate (PMMA) were carried out in ten patients. Three of these had a recurrence after five years, but seven had no signs of relapse during a mean follow-up of 52 months. We believe that the combination of antihelminthic therapy, wide resection and the use of PMMA gives the best outcome in the treatment of bone hydatidosis.

Between January 1992 and December 1998, we treated 24 patients with necrotising fasciitis of a limb. There were 15 men and nine women with a mean age of 59.8 years (5 to 86). The infection was usually confused with cellulitis. Exquisite pain and early systemic toxicity were the most consistent clinical features. Diabetes mellitus and hepatic cirrhosis were the most commonly associated medical diseases. One third of the patients died. Those with involvement of the limbs above the knee or elbow on admission had a significantly higher rate of mortality than those with distal lesions (Fisher’s exact test, p = 0.027). There was no correlation between mortality and advanced age (Student’s t-test, p = 0.22) or between amputation and survival (Fisher’s exact test, p = 0.39).

We reviewed all 717 manuscripts published in the 1997 issues of the British and American volumes of the Journal of Bone and Joint Surgery and in Clinical Orthopaedics and Related Research, from which 33 randomised, controlled trials were identified. The results and sample sizes were used to calculate the statistical power of the study to distinguish small (0.2 of standard deviation), medium (0.5 of standard deviation), and large (0.8 of standard deviation) effect sizes.

Of the 33 manuscripts analysed, only three studies (9%) described calculations of sample size. To perform post-hoc power assessments and estimations of deficiencies of sample size, the standard effect sizes of Cohen (small, medium and large) were calculated. Of the 25 studies which reported negative results, none had adequate power (β < 0.2) to detect a small effect size and 12 (48%) lacked the power necessary to detect a large effect size. Of the 25 studies which did not have an adequate size of sample to detect small differences, the average used was only 10% of the required number

Our findings suggest that randomised, controlled trials in clinical orthopaedic research utilise sample sizes which are too small to ensure statistical significance for what may be clinically important results.

We studied prospectively a consecutive series of 50 patients with chronic osteomyelitis. Patients were allocated to the following treatment groups: 1) wide resection, with a clearance margin of 5 mm or more; 2) marginal resection, with a clearance margin of less than 5 mm; and 3) intralesional biopsy, with debulking of the infected area. All patients had a course of antibiotics, intravenously for six weeks followed by orally for a further six weeks. No patients in group 1 had recurrence. In patients treated by marginal resection (group 2), 8 of 29 (28%) had recurrence. All patients who had debulking had a recurrence within one year of surgery. We performed a survival analysis to determine the time of the recurrence of infection. In group 2 there was a higher rate of recurrence in type-B hosts (p < 0.05); no type-A hosts had recurrence. This information is of use in planning surgery for chronic osteomyelitis.

There is a narrow line between the benefits and risks of anticoagulant therapy. Many factors influence a patient’s response to warfarin, and careful monitoring is required to ensure that the therapeutic level of anticoagulation is achieved. The purpose of this retrospective review was to examine the relationship between the postoperative response to warfarin and the preoperative level of haemoglobin. The results showed that lower preoperative levels of haemoglobin are associated with an increased response to warfarin (p = 0.01).

We have studied prospectively the outcome of wound discharge in patients after arthroplasty of the hip and knee. Over a period of 3.5 years 530 primary arthroplasties were carried out in one hospital. Postoperative wound infections developed in 82. At a mean follow-up of two years a comparison was made between these patients and 82 with healthy wounds, in terms of symptoms and signs of deep infection.

There was an incidence of 1.1% of early deep infection, within six weeks in all cases. The rate of ‘superficial’ infection was 17.3% in the hips, 10.5% in the knees and 14.3% in total. At a mean follow-up of 26 months, there were no significant differences between the patients with infected wounds and a matched group of patients with healthy wounds in terms of the ESR, level of C-reactive protein, white cell count and radiological scores, but clinical scores were significantly worse in the patients with infected knees (p < 0.05). The length of stay was also significantly longer in this group (mean 14.6 days in the healthy wound group, 19 days in the problem group; p < 0.005). There was, however, no convincing evidence that these wound infections led to deep infection and early revision in the early to medium follow-up period. A larger and longer prospective trial would be necessary to shed more light on this potential problem.

We studied the sensitivity and specificity of magnetic resonance arthrography (MRa) for the diagnosis of lesions of the acetabular labrum in 20 cadaver hips. The MRa results were compared with macroscopic and histological findings.

We found that the labrum could be satisfactorily delineated by MRa and that large detachments could be identified satisfactorily. The diagnosis of small detachments and degeneration of the labrum was less reliable.