Alignment in total knee replacement.

The advent of computer-assisted knee replacement surgery has focused interest on the alignment of the components. However, there is confusion at times between the alignment of the limb as a whole and that of the components. The interaction between them is discussed in this article. Alignment is expressed relative to some reference axis or plane and measurements will vary depending on what is selected as the reference. The validity of different reference axes is discussed. Varying prosthetic alignment has direct implications for surrounding soft-tissue tension. In this context the interaction between alignment and soft-tissue balance is explored and the current knowledge of the relationship between alignment and outcome is summarised.

Computer-assisted total knee replacement. A controlled cadaver study using a multi-parameter quantitative CT assessment of alignment (the Perth CT Protocol).

A controlled study, comparing computer- and conventional jig-assisted total knee replacement in six cadavers is presented. In order to provide a quantitative assessment of the alignment of the replacements, a CT-based technique which measures seven parameters of alignment has been devised and used. In this a multi-slice CT machine scanned in 2.5 mm slices from the acetabular roof to the dome of the talus with the subject's legs held in a standard position. The mechanical and anatomical axes were identified, from three-dimensional landmarks, in both anteroposterior and lateral planes. The coronal and sagittal alignment of the prosthesis was then measured against the axes. The rotation of the femoral component was measured relative to the transepicondylar axis. The rotation of the tibial component was measured with reference to the posterior tibial condyles and the tibial tuberosity. Coupled femorotibial rotational alignment was assessed by superimposition of the femoral and tibial axial images. The radiation dose was 2.7 mSV. The computer-assisted total knee replacements showed better alignment in rotation and flexion of the femoral component, the posterior slope of the tibial component and in the matching of the femoral and tibial components in rotation. Differences were statistically significant and of a magnitude that support extension of computer assistance to the clinical situation.

Computer-assisted revision total knee replacement.

A technique for performing allograft-augmented revision total knee replacement (TKR) using computer assistance is described, on the basis of the results in 14 patients. Bone deficits were made up with impaction grafting. Femoral grafting was made possible by the construction of a retaining wall or dam which allowed pressurisation and retention of the graft. Tibial grafting used a mixture of corticocancellous and morsellised allograft. The position of the implants was monitored by the computer system and adjusted while the cement was setting. The outcome was determined using a six-parameter, quantitative technique (the Perth CT protocol) which measured the alignment of the prosthesis and provided an objective score. The final outcomes were not perfect with errors being made in femoral rotation and in producing a mismatch between the femoral and tibial components. In spite of the shortcomings the alignments were comparable in accuracy with those after primary TKR. Computer assistance shows considerable promise in producing accurate alignment in revision TKR with bone deficits.

Psychological aspects of chronic low back pain.

BACKGROUND: Patients with chronic low back pain present physicians with diagnostic and therapeutic problems. Physical treatments tend to have low success rates and it is postulated that this may be because low back pain can be a manifestation of abnormal illness behaviour. METHODS: A structured prospective study determined the prevalence of somatization in a sample of 131 adult patients with chronic low back pain using the Illness Behaviour Questionnaire (IBQ) and the Modified Somatic Perception Questionnaire (MSPQ). The scores on these psychological questionnaires were compared with the blind interpretation of pain distribution drawings and with the results of a mechanical classification of the patient's symptoms and signs. RESULTS: Fifty-four per cent of patients had four or more (out of five) abnormal illness indicators. The MSPQ values for the group were significantly above the control values in the literature. Thirty-two per cent of pain diagrams were thought to be incompatible with an organic cause when assessed by an orthopaedic surgeon and sixty-two per cent when assessed by a psychiatrist. CONCLUSIONS: Psychosocial factors are dominant in the presentation of chronic low back pain in adults and the disorder is not primarily a musculoskeletal one.

Bone density after rigid plate fixation of tibial fractures. A dual-energy X-ray absorptiometry study.

We used dual-energy X-ray absorptiometry (DEXA) to measure the bone mineral content (BMC) of both tibiae in 13 patients who had been treated for a tibial fracture by rigid plate fixation. Within two weeks of plate removal the BMC was significantly greater in the bone that had been under the plate than at the same site in the control tibia. An unplated area of bone near the ankle showed a significant decrease in BMC at the time of plate removal with subsequent return to the level of the control tibia during the ensuing 18 months. We conclude that osteoinductive influences outweigh the potential causes of osteopenia, such as stress shielding and disuse, and that, contrary to expectation, demineralisation is not a factor in the diminished strength of the tibia after plating for fracture.

Intraosseous thrombosis in ischemic necrosis of bone and osteoarthritis.

It has been proposed that nontraumatic ischemic necrosis of bone (INB) is a result of lipid associated intraosseous thrombosis. A histological study of 15 patients with INB confirmed the presence of intravascular lipid and thrombosis in the vessels of the femoral head. A similar analysis of 11 patients with primary osteoarthritis (OA) showed similar changes at lower levels. These changes were not observed in seven control femoral heads. The possibility that both INB and OA result from intraosseous thrombosis is discussed.

The Domiciliary Rehabilitation and Support Program. Rationale, organisation and outcome.

OBJECTIVE: To describe the Domiciliary Rehabilitation and Support Program (whose principles are early surgery, rapid mobilisation, avoidance of sedation, and early discharge with physiotherapy and nursing support provided in the home) for elderly patients with proximal femoral fractures (PFF), and to compare its costs with those of a conventional approach to the problem. DESIGN AND SETTING: Prospective data accumulation on all patients admitted to a major metropolitan teaching hospital (Sir Charles Gairdner Hospital). PATIENTS: Six hundred and fifteen patients, 60 years or more, 76% female (mean age 82.6 +/- 8.1 years), 24% male (mean age 79.9 +/- 7.6 years). RESULTS: The mean length of hospital stay of patients on the program was 18.9 (+/- 27.3) days compared with 28 days for elderly PFF patients in the preceding year. The morbidity and mortality figures were comparable with or better than other published series. There was a 15% financial saving following introduction of the scheme. CONCLUSION: The Domiciliary Rehabilitation and Support Program is a safe and cost effective method of dealing with elderly patients suffering from a proximal femoral fracture.

OASYS: a computerized auditing system for orthopaedic surgery.

Medical auditing based on individual diagnoses or specific therapies is well established. Auditing of all medical activity has an expanding role in quality assurance and research. In an attempt to overcome the limitations of existing auditing systems, a fundamentally different, flexible, high quality and easily accessible orthopaedic auditing system has been developed. This records a description of each component of patients' orthopaedic diagnoses, records treatment and complications, produces discharge letters and surgical log books and allows flexible and comprehensive audits. It has been in use in an orthopaedic service since January 1990 and has been successful in identifying problems and monitoring the effectiveness of changes. It is anticipated that the system will become more widely used and provide the basis for a 'user group' which will share the accumulated data and further development costs.

Orthopaedic basis for occupationally related arm and neck pain.

A prospective clinical study of 204 individuals with occupationally related upper limb or neck pain was initiated to determine the major symptom patterns, the physical findings, and changes in laboratory tests that are exhibited by these subjects. On the basis of this information it was possible to determine the proportion that was suffering from a recognizable, pathologically discrete, musculoskeletal disorder. The study shows that in the majority (58%) of these people, a discrete musculoskeletal disorder exists. The most common diagnoses were peripheral nerve entrapments (19%) and arthropathies (16%). In 42% a discrete diagnosis was not made and the nature of the disorder, in these, is discussed.

Objective and useful mobility assessment of patients with arthropathy of the hip and knee.

Walking ability was objectively assessed by measurements of endurance, oxygen consumption, and pulse rate response. Twenty-four control subjects and 38 patients with arthropathy of the hip or knee were asked to walk on a treadmill, initially at 1 km/hour, for four minutes. The speed was increased by 1 km/hour every four minutes, until the subjects has walked for four minutes at 7 km/hour, or until they could not continue. Oxygen consumption, heart rate, cadence, and step length were measured. The controls could all walk for 1400 m, reaching a walking speed of 6 km/hour, and showed a consistent relation between heart rate, oxygen consumption, and speed of walking. The majority of arthritic patients failed to reach either this distance or speed. They had a significantly increased metabolic cost, and there was a good correlation (r = 0.65 to 0.99) between the changes in pulse rate and oxygen consumption in each individual patient. The endurance, heart rate response, and oxygen consumption changes shown by patients proved to be reproducible characteristics in patients whose disease was static.

A rationalized approach to physiotherapy for low-back pain.

A systematic approach to low-back pain is presented that relies on the classification of patients according to their symptoms. Rational systems of physiotherapy are proposed for each group and incorporated into an algorithmn. One hundred forty-two patients with mechanical low-back pain have been treated, and their response has been assessed by means of a postal questionnaire. Patients were offered an educational program, exercises, spinal manipulation, spinal supports, and analgesic medication. Eighteen percent of patients became completely free of pain, and 59% experienced a reduction in pain level. The most effective treatment was education in back care, followed closely by an exercise program. The responses were different in the various subgroups, and a series of revised flow charts is presented.

The rapid transit system for patients with fractures of proximal femur.

The rapid transit system for patients with fractures of the proximal femur consists of immediate internal fixation or replacement of the fractured bone under spinal anaesthesia, without any sedation. Patients are mobilised within hours of surgery and sent home as soon as they can walk. They are supervised at home by both an experienced physiotherapist and a visiting nurse. Sixty nine patients admitted to a metropolitan teaching hospital were considered for the system and 50 were accepted. Their age distribution and level of general ill health were comparable with those in other series. The rapid transit system resulted in 90% of patients accepted being discharged to their homes within the first five days, with a lower morbidity and a mortality at three months of 7%. Using the rapid transit system rehabilitation in the original environment is difficult only if the patient lives alone, and even then temporary support is often enough to allow them to return home.

Orthopaedic audit: a comprehensive system for in-patients.

Problem Oriented Summary, Audit, Discharge (POSAD) is presented as a system which permits auditing of in-patient admissions. It is prospective, comprehensive, simple to operate and generates an immediate discharge summary. it has replaced the conventional hospital discharge summary and therefore does not increase secretarial or medical workload. It can be run either as a paper-based system or computerized. The work profile and quality control information that has resulted from the 1982 auditing of the Hollywood Orthopaedic Service is presented. This service involves eight consultant orthopaedic staff who dealt with 2,322 hospital patient admissions in that year. Auditing/peer review has shown up wide variations in surgical behaviour and the workload undertaken by individuals. The information that has been produced has enabled the surgeons of this service to put into effect three significant innovations. These are: (a) Regular analysis of complications. (b) Rank ordering (comparison) of individual surgeons. (c) Ready access to current statistics.

Fat and thromboembolism after total hip replacement.

Three patients who died after total hip replacement were subjected to a necropsy examination. The object of this was to determine whether there was any evidence of a relationship between fat emboli produced by the surgery and thrombotic complications. All three patients showed extensive fat embolisation in the lungs and antemortem thrombosis. In two of these the morphological relationship between these two phenomena was such that it seems likely that the fat emboli preceded and caused the thrombosis.

Venous thrombosis produced by the local injection of fat.

An experimental study performed in 16 mongrel dogs is presented, which shows that when venous stasis is combined with the local injection of non-esterified fatty acid an intense thrombosis results. This response is not produced by venous stasis alone, nor by the combination of venous stasis and triacylglycerol. Histologically it is quite different from the response produced by an inert intraluminal foreign body. It does resemble venous thrombosis described experimentally and in patients. The clinical relevance of these findings is that during accidental or operative trauma to a long bone, fat is commonly forced into the local venous circulation. If this event is combined with venous stasis or a tourniquet is used, then the circumstances of this experiment are reproduced. It is suggested that the venous thrombosis which commonly complicates long-bone injury or operation is in part caused by the thrombogenic nature of the introduced fat.