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The pathogenesis of longitudinal reduction deformities of the limbs, or dysmelia, is still a matter of debate. Their morphological pattern was defined from a large collection of radiographs of children with dysmelia following the thalidomide disaster.
We compared radiographs of 378 of these limbs with the sclerotomes which are areas of segmental sensory innervation of the limb skeleton defined by the radiation of referred pain. The pattern of dysmelia matched the sclerotomes closely in 279 limbs (73.5%).
The principles of skeletal reduction in dysmelia are explained by the arrangement of the sclerotomes. The congruence between two separate and independent data sets shows that both patterns are expressions of the underlying segmental sensory innervation of the skeleton, and that the sensory nervous system is involved in the process of limb morphogenesis and teratogenesis.
The radiolucent lines and the stability of the components of 66 knee arthroplasties were assessed by six orthopaedic surgeons on conventional anteroposterior and lateral radiographs and on fluoroscopic views which had been taken on the same day. The examiners were blinded as to the patients and clinical results. The interpretation of the radiographs was repeated after five months.
On fluoroscopically-assisted radiographs four of the six examiners identified significantly more radiolucent lines for the femoral component (p < 0.05) and one significantly more for the tibial implant. Five examiners rated more femoral components as radiologically loose on fluoroscopically-assisted radiographs (p = 0.0008 to 0.0154), but none did so for the tibial components. The mean intra- and interobserver kappa values were higher for fluoroscopically-assisted radiographs for both components.
We have shown that fluoroscopically-assisted radiographs allow more reproducible, and therefore reliable, detection of radiolucent lines in total knee arthroplasty. Assessment of the stability of the components is significantly influenced by the radiological technique used. Conventional radiographs are not adequate for evaluation of the stability of total knee arthroplasty and should be replaced by fluoroscopically-assisted films.
As part of a prospective study of 476 total knee replacements (TKR), we evaluated the use of manipulation under anaesthesia in 47 knees. Manipulation was considered when intensive physiotherapy failed to increase flexion to more than 80°. The mean time from arthroplasty to manipulation was 11.3 weeks (median 9, range 2 to 41). The mean active flexion before manipulation was 62° (35 to 80). One year later the mean gain was 33° (Wilcoxon signed-rank test, range −5 to 70, 95% CI 28.5 to 38.5). Definite sustained gains in flexion were achieved even when manipulation was performed four or more months after arthroplasty (paired
A further 21 patients who met our criteria for manipulation declined the procedure. Despite continued physiotherapy, there was no significant increase in flexion in their knees. Six weeks to one year after TKR, the mean change was 3.1° (paired
We assessed the influence of the use of a tourniquet in total knee arthroplasty in a prospective, randomised study. After satisfying exclusion criteria, we divided 77 patients into two groups, one to undergo surgery with a tourniquet and one without. Both groups were well matched. The mean change in knee flexion in the group that had surgery without a tourniquet was significantly better at one week (p = 0.03) than in the other group, but movement was similar at six weeks and at four months. There was no significant difference in the surgical time, postoperative pain, need for analgesia, the volume collected in the drains, postoperative swelling, and the incidence of wound complications or of deep-venous thrombosis.
We conclude that the use of a tourniquet is safe and that current practice can be continued.
Two men, aged 21 and 50 years, were seen with ossification of the patellar tendon after injury to the knee in adolescence. They complained of pain and had patella alta. Large bony masses were excised from below the affected patellae. The patellar tendon was then reconstructed using a Leeds-Keio ligament. The results at six and ten years, respectively, were good, with neither patient having pain or an extension lag.
We present the first study in vivo of meniscal movement in normal knees under load. Using an open MR scanner, allowing imaging in physiological positions in near to real-time, 16 young footballers were scanned moving from full extension to 90° flexion in the sagittal and coronal planes. Excursion of the meniscal horns, radial displacement and meniscal height were measured.
On weight-bearing, the anterior horn of the medial meniscus moves through a mean of 7.1 mm and the posterior horn through 3.9 mm, with 3.6 mm of mediolateral radial displacement. The height of the anterior horn increases by 2.6 mm and that of the posterior horn by 2.0 mm. The anterior horn of the lateral meniscus moves 9.5 mm and the posterior horn 5.6 mm, with 3.7 mm of radial displacement. The height of the anterior horn increases by 4.0 mm, and that of the posterior horn by 2.4 mm. In non-weight-bearing, the anterior horn of the medial meniscus moves 5.4 mm and the posterior horn 3.8 mm, with 3.3 mm of radial displacement. The anterior horn of the lateral meniscus moves 6.3 mm, and the posterior horn 4.0 mm, with 3.4 mm of radial displacement. The most significant differences between weight-bearing and non-weight-bearing were the movement and vertical height of the anterior horn of the lateral meniscus.
Primary total hip arthroplasty (THA) is one of the most effective ways of improving quality of life (QoL). We have compared the improvement in QoL in 62 patients who had a cemented revision of a THA with that of 62 primary replacements.
One year after operation the median QoL score had been significantly improved in both groups; from 0.870 to 0.990 in the primary group (p < 0.0001) and from 0.870 to 0.980 in the revised group (p < 0.0001). There was no significant difference in the improvement in scores between the groups (p = 0.29).
When reviewed after four years there was no difference in the pain score for either group (p = 0.89), but that for function had deteriorated significantly. This was associated with revision surgery (p = 0.018) and a low preoperative QoL score (p = 0.004).
We conclude that both primary and revision operations give a significant improvement in the QoL but function after revision may be less durable than after a primary arthroplasty.
Osteolysis is due to particulate wear debris and is responsible for the long-term failure of total hip replacements. It has stimulated the development of alternative joint surfaces such as metal-on-metal or ceramic-on-ceramic implants.
Since 1988 the second-generation metal-on-metal implant Metasul has been used in over 60 000 hips. Analysis of 118 retrieved specimens of the head or cup showed rates of wear of approximately 25 μm for the whole articulation per year in the first year, decreasing to about 5 μm per year after the third. Metal surfaces have a ‘self-polishing’ capacity. Scratches are worn out by further joint movement. Volumetric wear was decreased some 60-fold compared with that of metal-on-polyethylene implants, suggesting that second-generation metal-on-metal prostheses may considerably reduce osteolysis.
We carried out 71 primary total hip arthroplasties using porous-coated, hemispherical press-fit Duraloc ‘100 Series’ cups in 68 consecutive patients; 61 were combined with the cementless Spotorno stem and ten with the cemented Lubinus SP II stem. Under-reaming of 2 mm achieved a press-fit. Of the 71 hips, 69 (97.1%) were followed up after a mean of 2.4 years. Migration analysis was performed by the Ein Bild Röntgen Analyse method, with an accuracy of 1 mm.
The mean total migration after 24 months was 1.13 mm. Using the definition of loosening as a total migration of 1 mm, it follows that 30 out of 63 cups (48%) were loose at 24 months.
We report the results of our continued review of 14 hip arthroplasties using alumina ceramic femoral heads with cross-linked polyethylene cups.
There have been no complications and a very low rate of penetration. This was 0.02 mm per year after an initial ‘bedding-in’ period of two years. There has been no change in the mean rate between our earlier study at six years and the current results at 10 to 11 years.
The use of these bearing surfaces appears to reduce the potential amount of polyethylene debris and may provide the next logical stage in the development of the Charnley low-friction arthroplasty.
Dental procedures may lead to a transient bacteraemia lasting for up to 30 minutes. Of the numerous cases of total hip arthroplasty (THA) reported which have been infected from haematogenous sources, dental procedures have been involved only infrequently. We reviewed the records of 2973 patients after THA. Of the late infections identified in 52 patients, three (6%) were strongly associated with a dental procedure. Infection was diagnosed by culture from the affected joint;
Infection of a THA after dental procedures is more common than has been previously suspected. Patients with systemic disease, or who are undergoing extensive procedures, should be considered for prophylactic antibiotic treatment.
We have examined the effect of the Wagner spherical acetabular osteotomy on preserving the joint in 38 hips with a mean follow-up of 17 years. At the time of the initial operation, 55% of patients had clinical symptoms and 30 joints showed minimal or absent radiological signs of osteoarthritis. At follow-up, 54% of patients had a good functional result.
The osteotomy improved the mean centre-edge angle from −3° to +15°, the mean anterior centre-edge angle to 23° and the acetabular head index to 75%. The obliquity of the acetabular roof decreased from 28° to 16°. One patient improved, but 14 deteriorated with joint degeneration. Of these, one progressed because of postoperative deep-tissue infection and five due to undercorrection. One patient needed total joint replacement after 14 years. At 17 years after operation, Wagner osteotomy had prevented progression of secondary arthritis in 63% of cases.
To assess the stability of the hip after acetabular fracture, dynamic fluoroscopic stress views were taken of 41 acetabular fractures that met the criteria for non-operative management. These included roof arcs of 45°, a subchondral CT arc of 10 mm, displacement of less than 50% of the posterior wall, and congruence on the AP and Judet views of the hip. There were three unstable hips which were treated by open reduction and internal fixation. The remaining 38 fractures were treated non-operatively with early mobilisation and delayed weight-bearing. At a mean follow-up of 2.7 years, the results were good or excellent in 91% of the cases. Three fair results were ascribed to the patients’ other injuries. Dynamic stress views can identify subtle instability in patients who would normally be considered for non-operative treatment.
We have carried out a prospective study to determine whether the basic descriptive criteria and classifications of diaphyseal fractures of the tibia determine prognosis, as is widely believed. A number of systems which are readily available were used, with outcome being determined by standard measurements including fracture union, the need for secondary surgery and the incidence of infection. Many validated functional outcomes were also used. The Tscherne classification of closed fractures proved to be slightly more predictive of outcome than the others, but our findings indicate that such systems have little predictive value.
In three consecutive years 462 patients over the age of 60 years presented at Waikato Hospital, Hamilton, New Zealand, with a fracture of the proximal femur. Within two years, 11 (2.4%) returned with a fracture of the contralateral femur. If the effectiveness of any form of treatment aiming at reducing the incidence of contralateral fracture were subjected to a trial, a sample size of 5000, randomly distributed equally between treatment and placebo groups, would be needed for the trial to have a power of 80% to detect a reduction.
We undertook a radiological analysis of 186 standard Souter implants to determine survivorship and to analyse the pattern of failure in those needing revision. The implants had been inserted as a primary procedure in patients with rheumatoid arthritis of the elbow at our hospital over the last 12 years.
Taking revision as an endpoint, the survivorship after 12 years was 87%. If, however, revision and loosening, defined as the Hindex value equivalent to demarcation of 1 mm around the whole implant, are also included, the survivorship falls to 80%. Of the 24 implants revised, 18 (75%) were for problems with the humeral component, three (12.5%) with the ulnar component and three (12.5%) for instability.
Loosening of the humeral component occurred when the implant extended into the humerus, with the tip moving anteriorly on to the anterior humeral cortex. Our study indicates that loosening can be predicted by the rate of change in this angle of extension of the prosthesis.
We studied 45 patients with 46 fractures of the scaphoid who presented sequentially over a period of 21 months. MRI enabled us to relate the pattern of the fracture to the blood supply of the scaphoid. Serial MRI studies of the four main patterns showed that each followed a constant sequence during healing and failure to progress normally predicted nonunion.
Acute fractures of the scaphoid were randomly allocated for conservative treatment in a Colles’-type plaster cast with the wrist immobilised in either 20° flexion or 20° extension. The position of the wrist did not influence the rate of union of the fracture (89%) but when reviewed after six months the wrists which had been immobilised in flexion had a greater restriction of extension. We recommend that acute fractures of the scaphoid should be treated in a Colles’-type cast with the wrist in slight extension.
We studied retrospectively a consecutive series of 547 shoulders in 529 patients undergoing operation for instability. In 41, the cause of instability was considered to be lateral avulsion of the capsule, including the inferior glenohumeral ligament, from the neck of the humerus, the HAGL lesion. In 35, the lesion was found at first exploration, whereas in six it was noted at revision of a previous failed procedure. In both groups, the patients were older on average than those with instability from other causes. Of the primary cases, in 33 (94.3%) the cause of the first dislocation was a violent injury; six (17.4%) had evidence of damage to the rotator cuff and/or the subscapularis. Only four (11.4%) had a Bankart lesion. In patients undergoing a primary operation in whom the cause of the first dislocation was a violent injury, who did not have a Bankart lesion and had no suggestion of multidirectional laxity, the incidence of HAGL was 39%.
In 12 infants aged under 16 months with unilateral club foot we used MRI in association with multiplanar reconstruction to calculate the volume and principal axes of inertia of the bone and cartilaginous structures of the hindfoot.
The volume of these structures in the club foot is about 20% smaller than that in the normal foot. The reduction in volume of the ossification centre of the talus (40%) is greater than that of the calcaneus (20%). The long axes of both the ossification centre and the cartilaginous anlage of the calcaneus are identical in normal and club feet. The long axis of the osseous nucleus of the talus of normal and club feet is medially rotated relative to the cartilaginous anlage, but the angle is greater in club feet (10°
A six-year-old girl with congenital sensory neuropathy with anhidrosis (CSNA) presented with bilateral hip dysplasia and subluxation on the right side.
Conservative treatment of the hips by closed reduction and a plaster cast was unsuccessful. When aged seven years the patient had an intertrochanteric varus rotation osteotomy on the right side, but subluxation was again evident after five months. A Salter-type pelvic osteotomy was carried out followed by immobilisation, but one year later subluxation was present in the right hip and dislocation in the left. At the age of nine years, the right femoral head resembled a Charcot joint, although walking ability was preserved.
In patients with CSNA, surgery may not always be advisable.
Fresh-frozen allografts from the humerus were used to help to stabilise the spine after anterior decompression for tuberculosis in 47 children with a mean age of 4.2 years (2 to 9). The average angle of the gibbus, before operation, was 53°; at follow-up, two years later, it was 15°. Rejection of the graft or deep sepsis was not seen. Cross trabeculation between the allograft and the vertebral body was observed at six months, with remodelling occurring at approximately 30 months.
The ratio of the sagittal diameter of the cervical canal to the corresponding diameter of the vertebral body has been described as a reliable means for assessing stenosis of the canal and detecting those at risk of cervical neuropraxia. The use of ratio techniques has the advantage of avoiding variation in magnification when direct measurements are made from plain radiographs. We examined the reliability of this method using plain lateral radiographs of unknown magnification and CT scans. We also assessed other possible ratios of anatomical measurements as a guide to the diameter of the canal.
Our findings showed a poor correlation between the true diameter of the canal and the ratio of its sagittal diameter to that of the vertebral body. No other more reliable ratio was identified. The variability in anatomical morphology means that the use of ratios from anatomical measurements within the cervical spine is not reliable in determining the true diameter of the cervical canal.
We describe a surgical technique for ankle arthrodesis using an anterior approach to the ankle and internal fixation with an anteriorly-placed AO T plate.
A total of 33 patients who had ankle arthrodeses have been followed retrospectively. Thirty-one (94%) of the ankles fused although two patients developed tibial stress fractures. Four patients had a superficial infection which did not prevent union.
The surgical technique is simple, easily reproducible and gives excellent clinical results with a high rate of union.
In impaction grafting of contained bone defects after revision joint arthroplasty the graft behaves as a friable aggregate and its resistance to complex forces depends on grading, normal load and compaction. Bone mills in current use produce a distribution of particle sizes more uniform than is desirable for maximising resistance to shear stresses.
We have performed experiments in vitro using morsellised allograft bone from the femoral head which have shown that its mechanical properties improve with increasing normal load and with increasing shear strains (strain hardening). The mechanical strength also increases with increasing compaction energy, and with the addition of bioglass particles to make good the deficiency in small and very small fragments. Donor femoral heads may be milled while frozen without affecting the profile of the particle size. Osteoporotic femoral heads provide a similar grading of sizes, although fewer particles are obtained from each specimen. Our findings have implications for current practice and for the future development of materials and techniques.
We carried out limb lengthening in rabbits and then transplanted osteoblast-like cells derived from the tibial periosteum to the centres of distracted callus immediately after distraction had been terminated. Two weeks later the transaxial area ratio at the centre of the distracted callus and the bone mineral density (BMD) were significantly higher in the transplanted group, by 21% and 42%, respectively, than in the non-injected group or the group injected with physiological saline (p < 0.05). Callus BMD as a percentage of density in uninvolved bone was also significantly higher in the transplanted group (p < 0.05) than in the other two groups, by 27% and 20% in the second and fourth weeks, respectively (p < 0.05). Mechanically, the callus in the transplanted group tended to be stronger as shown by the three-point bending test although the difference in fracture strength was not statistically significant.
Our results show that transplantation of osteoblast-like cells promotes maturity of the distracted callus as observed at the second and fourth weeks after lengthening. The method appears promising as a means of shortening the consolidation period of callus distraction and decreasing complications during limb lengthening with an external fixator.
Studies using roentgen stereophotogrammetric analysis (RSA) have shown that the femoral components of cemented total hip replacements (THR) migrate distally relative to the bone, but it is not clear whether this occurs at the cement-implant or the cement-bone interface or within the cement mantle. Our aim was to determine where this migration occurred, since this has important implications for the way in which implants function and fail.
Using RSA we compared for two years the migration of the tip of the stem with that of the cement restrictor for two different designs of THR, the Exeter and Charnley Elite. We have assumed that if the cement restrictor migrates, then at least part of the cement mantle also migrates.
Our results have shown that the Exeter migrates distally three times faster than the Charnley Elite and at different interfaces. With the Exeter migration was at the cement-implant interface whereas with the Charnley Elite there was migration at both the cement-bone and the cement-implant interfaces.
We revised 24 consecutive hips with loosening of the femoral stem using impaction allograft and a cemented stem with an unpolished proximal surface. Repeated radiostereometric examinations for up to two years showed a slow rate of subsidence with a mean of 0.32 mm (−2.0 to +0.31). Fifteen cases followed for a further year showed the same mean subsidence after three years, indicating stabilisation. A tendency to retroversion of the stems was noted between the operation and the last follow-up. Retroversion was also recorded when displacement of the stem was studied in ten of the patients after two years. Repeated determination of bone mineral density showed an initial loss after six months, followed by recovery to the postoperative level at two years. Defects in the cement mantle and malalignment of the stem were often noted on postoperative radiographs, but did not correlate with the degrees of migration or displacement. After one year, increasing frequency of trabecular remodelling or resorption of the graft was observed in the greater trochanter and distal to the tip of the stem. Cortical repair was noted distally and medially (Gruen regions 3, 5 and 6). Migration of the stems was the lowest reported to date, which we attribute to the improved grafting technique and to the hardness of the graft.
CT and advanced computer-aided design techniques offer the means for designing customised femoral stems. Our aim was to determine the Hounsfield (HU) value of the bone at the corticocancellous interface, as part of the criteria for the design algorithm.
We obtained transverse CT images from eight human cadaver femora. The proximal femoral canal was rasped until contact with dense cortical bone was achieved. The femora were cut into several sections corresponding to the slice positions of the CT images. After obtaining a computerised image of the anatomical sections using a scanner, the inner cortical contour was outlined and transferred to the corresponding CT image. The pixels beneath this contour represent the CT density of the bone remaining after surgical rasping. Contours were generated automatically at nine HU levels from 300 to 1100 and the mean distance between the transferred contour and each of the HU-generated contours was computed.
The contour generated along the 600-HU pixels was closest to the inner cortical contour of the rasped femur and therefore 600 HU seem to be the CT density of the corticocancellous interface in the proximal part of cadaver femora. Generally, femoral bone with a CT density beyond 600 HU is not removable by conventional reamers. Thus, we recommend the 600 HU threshold as one of several criteria for the design of custom femoral implants from CT data.
We performed a histological and histomorphometric examination in five cadaver specimens of the femoral and acetabular components and the associated tissue which had been recovered between 3.3 and 6.2 years after primary total hip arthroplasty (THA) using a proximal hydroxyapatite (HA)-coated titanium alloy implant. All had functioned well during the patients’ life.
All the stems were fixed in the femur and showed osseointegration of both the proximal and distal parts. The amount of residual HA was greatest in the distal metaphyseal sections, indicating that the rate of bone remodelling may be the main factor causing loss of HA. The level of activity of the patient was the only clinical factor which correlated with loss of coating. The percentage of bone-implant osseointegration was almost constant, regardless of the amount of HA residue, periprosthetic bone density or the time of implantation. HA debris was seldom observed and if present did not cause any adverse or inflammatory reaction. Partial debonding did occur in one case as a result of a polyethylene-induced inflammatory reaction.
Particulate wear debris is associated with periprosthetic inflammation and loosening in total joint arthroplasty. We tested the effects of titanium alloy (Ti-alloy) and PMMA particles on monocyte/macrophage expression of the C-C chemokines, monocyte chemoattractant protein-1 (MCP-1), monocyte inflammatory protein-1 alpha (MIP-1α), and regulated upon activation normal T expressed and secreted protein (RANTES). Periprosthetic granulomatous tissue was analysed for expression of macrophage chemokines by immunohistochemistry. Chemokine expression in human monocytes/macrophages exposed to Ti-alloy and PMMA particles in vitro was determined by RT-PCR, ELISA and monocyte migration.
We observed MCP-1 and MIP-1α expression in all tissue samples from failed arthroplasties. Ti-alloy and PMMA particles increased expression of MCP-1 and MIP-1α in macrophages in vitro in a dose- and time-dependent manner whereas RANTES was not detected. mRNA signal levels for MCP-1 and MIP-1α were also observed in cells after exposure to particles. Monocyte migration was stimulated by culture medium collected from macrophages exposed to Ti-alloy and PMMA particles. Antibodies to MCP-1 and MIP-1α inhibited chemotactic activity of the culture medium samples.
Release of C-C chemokines by macrophages in response to wear particles may contribute to chronic inflammation at the bone-implant interface in total joint arthroplasty.
We analysed synovial fluid from 88 hips, 38 with osteoarthritis and 12 with well-functioning and 38 with loose hip prostheses. The levels of TNF-α, IL-1ß (71 hips) and IL-6 (45 hips) were measured using the ELISA technique. Joints with well-functioning or loose prostheses had significantly increased levels of TNF-α compared with those with osteoarthritis. Hips with aseptic loosening also had higher levels of IL-1ß but not of IL-6 compared with those without an implant. The levels of TNF-α and IL-1ß did not differ between hips with stable and loose prostheses.
Higher levels of TNF-α were found in hips with bone resorption of type II and type III (Gustilo-Pasternak) compared with those with type-I loosening.
The level of cytokines in joint fluid was not influenced by the time in situ of the implants or the age, gender or area of the osteolysis as measured on conventional radiographs.
Our findings support the theory that macrophages in the joint capsule increase the production of TNF-α at an early phase probably because of particle load and in the absence of clinical loosening. Since TNF-α has an important role in the osteolytic process, the interfaces should be protected from penetration of joint fluid.
Radiological assessment of the cement mantle is used routinely to determine the outcome of total hip replacement. We performed a simulated replacement arthroplasty on cadaver femora and took standard postoperative radiographs. The femora were then sectioned into 7 mm slices starting at the calcar, and high-resolution faxitron radiographs were taken of these sections.
Analysis of the faxitron images showed that defects in the cement mantle were observed up to 100 times more frequently than on the standard films. We therefore encourage the search for a better technique in assessing the cement mantle.
We studied the sensory afferent properties of normal, immobilised and inflamed rat knees by recording the activity of the medial articular nerve (MAN).
When the knee was inflamed by kaolin-carrageenan or immobilised for six weeks, MAN activity significantly increased during rest and continuous passive motion (CPM). The maximal discharge rate tended to increase depending on the angular velocity of the CPM. When the knees were then rested for one hour before again starting CPM, activity was further increased at the initial CPM cycle, the ‘post-rest effect’. Analysis of the conduction velocity showed that 94% and 66% of spike units on the recorded discharge of the immobilised and inflamed knees, respectively, belonged to fine nerve fibres.
Our findings show that the sensory receptors in the knee are sensitised in a similar manner by immobilisation and by inflammation, suggesting a relationship to pain. The post-rest effect may be related to a characteristic symptom of osteoarthritis called ‘starting pain’.
