1. The knee-chest position offers the surgeon excellent conditions for operations on lumbar intervertebral discs. 2. Hypotension on resumption of the prone or supine position is common: it is influenced by the anaesthetic technique, the physical state of the patient, the operation time and the extent of surgical bleeding. 3. The hypotension is thought to be due to poor perfusion of the lower limbs while the patient is in the knee-chest position

Leg amputation levels were decided in 24 patients suffering from atherosclerosis, using the conventional techniques of segmental blood pressure and radioisotope skin clearance. The skin microcirculation was measured and recorded before operation with a laser doppler flowmeter. A high correlation was found between the successful amputation levels and the maximal blood perfusion of the skin measured in this way

We carried out a prospective, randomised study of 62 patients to determine the efficacy of a foot sole pump (the A-V Impulse System) for the prevention of pulmonary embolism (PE) after hip surgery. PE was assessed by pulmonary perfusion scintigraphy before and after operation. We defined a PE as any new scintigraphic defect which was larger than a bronchopulmonary segment. The incidence of PE was 55% in the control group and 21% in the treatment group. The foot sole pump significantly reduced the incidence of PE (p = 0.008) and we encountered no side-effects from its use

Aims

The optimal management of an infrapopliteal deep venous thrombosis (IDVT) following total knee arthroplasty (TKA) remains unknown. The risk of DVT propagation and symptom progression must be balanced against potential haemorrhagic complications associated with administration of anticoagulation therapy. The current study reports on a cohort of patients diagnosed with IDVT following TKA who were treated with aspirin, followed closely for development of symptoms, and scanned with ultrasound to determine resolution of IDVT.

The incidence of deep vein thrombosis in 244 patients who had total knee replacement has been studied. In 120 the prosthesis was cemented and in 124 it was cementless. In all cases the replacement was primary and a porous-coated prosthesis with a porous-coated central tibial stem was used. Deep vein thrombosis was diagnosed by venography, and pulmonary embolism by perfusion scanning. The incidence of deep vein thrombosis in the cementless knees (23.8%) and in the cemented (25%) was approximately the same. The only significant predisposing factors for deep vein thrombosis in both groups were obesity, prolonged postoperative immobilisation, previous venous disease and hyperlipidaemia

The surgical correction of scoliosis in adolescents involves considerable trauma to bone and muscle which, together with hypotensive anaesthesia, might be expected to compromise renal function. Our recent observation of acute renal failure in two such patients prompted a prospective study of renal function following 52 operations in 43 patients. Despite hypotension, blood loss, muscle damage and evidence of fat embolism, renal function was unaltered in all patients, and there was no impairment of spinal cord function. Careful attention was paid to the maintenance of circulating volume which is essential to protect renal perfusion

Previous perfusion studies of the rotator cuff have demonstrated an area of hypovascularity in the distal part of the supraspinatus tendon. This has been implicated in the pathogenesis of its rupture. We performed a quantitative histological analysis of the vascularity of the tendons of supraspinatus and infraspinatus. Vessel number, size and the percentage of the tendon occupied by vessels were measured at 5 mm intervals from the humeral insertions to the muscle bellies. Both tendons were hypovascular in their distal 15 mm. No significant difference was demonstrated between the vascularity of supraspinatus and infraspinatus. We conclude that factors other than vascularity are important in the pathogenesis of supraspinatus rupture

We analysed the complication rate in 140 below-knee amputations in relation to surgical technique and the presence of diabetes. In all cases, the skin perfusion pressure was measured below the knee before operation to provide an objective evaluation of the microcirculation. In diabetic patients we found a significantly higher complication rate after using a long posterior flap than after equal sagittal flaps. No such difference could be demonstrated in non-diabetic patients. We suggest that the higher incidence of atherosclerotic lesions in the three major arteries below the knee in diabetic patients may account for the difference. We recommend the use of the sagittal technique for below-knee amputation in diabetic patients

Ischaemia resulting from increased joint pressure may play a role in the pathogenesis of necrosis of the femoral head epiphysis. We studied the effect of temporary vascular occlusion on this epiphysis in young rabbits. Occlusion for six hours resulted in necrosis of trabecular bone and of intertrabecular marrow and vascular tissue, later followed by revascularisation and repair, as has been demonstrated previously. In contrast, raised intra-articular pressure lasting for only two hours resulted in a more complex picture: trabecular osteocytes were dead, whereas the bone-forming marrow was shown by fluorochrome labelling to remain viable, and to form appositional repair bone throughout the epiphysis. We concluded that transient vascular occlusion may cause the death of trabeculae despite intact perfusion of the bone. This type of change may be important in the pathogenesis of Perthes' disease

Free patellar tendon grafts used for the intra-articular replacement of ruptured anterior cruciate ligaments (ACL) lack perfusion at the time of implantation. The central core of the graft undergoes a process of ischaemic necrosis which may result in failure. Early reperfusion of the graft may diminish the extent of this process. We assessed the role of peritendinous connective tissue in the revascularisation of the patellar tendon graft from the day of implantation up to 24 days in a murine model using intravital microscopy. The peritendinous connective-tissue envelope of the graft was either completely removed, partially removed or not stripped before implantation into dorsal skinfold chambers of recipient mice. Initial revascularisation of the grafts with preserved peritendinous connective tissues began after two days. The process was delayed by five to six times in completely stripped patellar tendons (p < 0.05). Only grafts with preserved connective tissues showed high viability whereas those which were completely stripped appeared to be subvital. The presence of peritendinous connective tissues accelerates the revascularisation of free patellar tendon grafts

Surgical dislocation of the hip is rarely undertaken. The potential danger to the vascularity of the femoral head has been emphasised, but there is little information as to how this danger can be avoided. We describe a technique for operative dislocation of the hip, based on detailed anatomical studies of the blood supply. It combines aspects of approaches which have been reported previously and consists of an anterior dislocation through a posterior approach with a ‘trochanteric flip’ osteotomy. The external rotator muscles are not divided and the medial femoral circumflex artery is protected by the intact obturator externus. We report our experience using this approach in 213 hips over a period of seven years and include 19 patients who underwent simultaneous intertrochanteric osteotomy. The perfusion of the femoral head was verified intraoperatively and, to date, none has subsequently developed avascular necrosis. There is little morbidity associated with the technique and it allows the treatment of a variety of conditions, which may not respond well to other methods including arthroscopy. Surgical dislocation gives new insight into the pathogenesis of some hip disorders and the possibility of preserving the hip with techniques such as transplantation of cartilage

The rate of success of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head may be improved if patients are preselected using MRI. We have used three criteria for selection for osteotomy (i) minor collapse of the infarcted area, loss of congruity or the crescent sign, without narrowing of the joint space or acetabular involvement (ii) patients younger than 55 years and with a painful hip (iii) patients with an intact area constituting an arc of more than 120° between the central vertical line of the femoral head and the posterior or anterior margin of the necrotic portion as seen on a midsagittal MRI. Seventeen patients were selected, with a follow-up of more than 42 months. A bone scan four weeks after operation showed adequate perfusion of the proximal segment in all hips. The hip score of Merle d’Aubigné et al improved from 13.5 points before operation to 17.2 points at the latest follow-up. Further collapse of the femoral head did not occur. The use of MRI instead of plain radiographs for the selection of patients has improved the success rate of transtrochanteric rotational osteotomy

We reviewed the records of 1257 patients having 1625 total knee arthroplasties; all had pre-operative and postoperative perfusion lung scans and postoperative venograms which were classified as showing no thrombi, calf thrombi or proximal thrombi. Patients with calf thrombi were found to have a significantly greater risk for both symptomatic and asymptomatic pulmonary embolism compared with patients with no venographic thrombi. There were positive lung scans in 6.9% of patients with calf thrombi compared with 2.0% of patients with negative venograms (p < 0.001). Symptomatic pulmonary embolism occurred in 1.6% of patients with calf thrombi compared with 0.2% of patients with negative venograms (p = 0.034). The risk of pulmonary embolism was not significantly different between patients with treated proximal thrombi, and those with calf thrombi. Patients who develop deep-vein thrombosis despite prophylaxis are at increased risk for pulmonary embolism; these patients should receive treatment, or undergo follow-up studies to detect proximal propagation

Aims

Complex fractures of the femur and tibia with associated severe soft tissue injury are often devastating for the individual. The aim of this study was to describe the two-year patient-reported outcomes of patients in a civilian population who sustained a complex fracture of the femur or tibia with a Mangled Extremity Severity Score (MESS) of ≥ 7, whereby the score ranges from 2 (lowest severity) to 11 (highest severity).

Aims

Spinal deformity surgery carries the risk of neurological injury. Neurophysiological monitoring allows early identification of intraoperative cord injury which enables early intervention resulting in a better prognosis. Although multimodal monitoring is the ideal, resource constraints make surgeon-directed intraoperative transcranial motor evoked potential (TcMEP) monitoring a useful compromise. Our experience using surgeon-directed TcMEP is presented in terms of viability, safety, and efficacy.

Previous dye-infusion experiments on cadavers have suggested that the hindfoot should be divided into four muscle compartments including a newly described ‘calcaneal’ element containing quadratus plantae. Since there are no clinical data to support this proposed division, we re-examined the validity of the infusion experiment. We made infusions of dilute Omnipaque at a constant rate into flexor digitorum brevis of four cadaver feet. We monitored the spread of the infusate by real-time CT imaging and measured the pressures at the infusion site by side-ported needles. In all feet, the barrier between flexor digitorum brevis and quadratus plantae became incompetent at pressures of less than 10 mmHg. Pressure gradients in this range cannot be expected to affect tissue perfusion significantly and independently generate compartment syndromes. These results do not confirm those of previous studies carried out by uncontrolled and unmonitored injections made by hand. Injection studies in cadaver limbs can give dramatically different results depending upon the assumptions made when designing the experiment. The technique cannot adequately act as a model of the physiology of the compartment syndrome. As the existence of a physiologically significant compartmental boundary between flexor digitorum brevis and quadratus plantae is based solely on a cadaver infusion experiment the presence of a ‘calcaneal’ compartment has not been confirmed

The primary source for the blood supply of the head of the femur is the deep branch of the medial femoral circumflex artery (MFCA). In posterior approaches to the hip and pelvis the short external rotators are often divided. This can damage the deep branch and interfere with perfusion of the head. We describe the anatomy of the MFCA and its branches based on dissections of 24 cadaver hips after injection of neoprene-latex into the femoral or internal iliac arteries. The course of the deep branch of the MFCA was constant in its extracapsular segment. In all cases there was a trochanteric branch at the proximal border of quadratus femoris spreading on to the lateral aspect of the greater trochanter. This branch marks the level of the tendon of obturator externus, which is crossed posteriorly by the deep branch of the MFCA. As the deep branch travels superiorly, it crosses anterior to the conjoint tendon of gemellus inferior, obturator internus and gemellus superior. It then perforates the joint capsule at the level of gemellus superior. In its intracapsular segment it runs along the posterosuperior aspect of the neck of the femur dividing into two to four subsynovial retinacular vessels. We demonstrated that obturator externus protected the deep branch of the MFCA from being disrupted or stretched during dislocation of the hip in any direction after serial release of all other soft-tissue attachments of the proximal femur, including a complete circumferential capsulotomy. Precise knowledge of the extracapsular anatomy of the MFCA and its surrounding structures will help to avoid iatrogenic avascular necrosis of the head of the femur in reconstructive surgery of the hip and fixation of acetabular fractures through the posterior approach

We describe a management strategy for upper- and lower-limb fractures with associated arterial injury and report the results in 113 cases treated over a period of 18 years. Primary amputation was performed in 23 patients and of those who underwent primary vascular repair, 27 needed secondary amputation, two-thirds of them within a week of the injury. Of those requiring secondary amputation, 51.8% had ischaemia exceeding six hours, 81.4% had severe soft-tissue injury and 85.2% had type III open fractures. The patients whose limbs had been salvaged were followed up for an average of 5.6 years. The eventual outcome depended on the severity of the fracture, the degree of soft-tissue damage, the length of the ischaemic period, the severity of neurological involvement, and the presence of associated major injuries. There was a 30% incidence of long-term disability in the salvaged limbs, largely due to poor recovery of neurological function. Prompt recognition of such combined injuries is vital and requires a high index of suspicion in patients with multiple injuries and with certain fracture patterns. We recommend a multidisciplinary approach, liberal use of pre-operative angiography in upper-limb injuries and selective use of intra-operative angiography in lower-limb injuries. Stable external or internal fixation of the fractures and re-establishment of limb perfusion are urgent surgical priorities to reduce the period of ischaemia which is critical for successful limb salvage

Aims

Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity.

Aims

Biofilm formation is one of the primary reasons for the difficulty in treating implant-related infections (IRIs). Focused high-energy extracorporeal shockwave therapy (fhESWT), which is a treatment modality for fracture nonunions, has been shown to have a direct antibacterial effect on planktonic bacteria. The goal of the present study was to investigate the effect of fhESWT on Staphylococcus aureus biofilms in vitro in the presence and absence of antibiotic agents.