The Cambridge Cup has been designed to replace the horseshoe-shaped articular cartilage of the acetabulum and the underlying subchondral bone. It is intended to provide physiological loading with minimal resection of healthy bone. The cup has been used in 50 women with displaced, subcapital fractures of the neck of the femur. In 24 cases, the cup was coated with hydroxyapatite. In 26, the coating was removed before implantation in order to simulate the effect of long-term resorption. The mean Barthel index and the Charnley-modified Merle d’Aubigné scores recovered to their levels before fracture. We reviewed 30 women at two years, 21 were asymptomatic and nine reported minimal pain. The mean scores deteriorated slightly after five years reflecting the comorbidity of advancing age. Patients with the hydroxyapatite-coated components remained asymptomatic, with no wear or loosening. The uncoated components migrated after four years and three required revision. This trial shows good early results using a novel, hydroxyapatite-coated, physiological acetabular component.
This paper reviews the current literature concerning the main clinical factors which can impair the healing of fractures and makes recommendations on avoiding or minimising these in order to optimise the outcome for patients. The clinical implications are described.
We compared the results of 146 patients who received an anatomic modular knee fixed-bearing total knee replacement (TKR) in one knee and a low contact stress rotating platform mobile-bearing TKR in the other. There were 138 women and eight men with a mean age of 69.8 years (42 to 80). The mean follow-up was 13.2 years (11.0 to 14.5). The patients were assessed clinically and radiologically using the rating systems of the Hospital for Special Surgery and the Knee Society at three months, six months, one year, and annually thereafter. The assessment scores of both rating systems pre-operatively and at the final review did not show any statistically significant differences between the two designs of implant. In the anatomic modular knee group, one knee was revised because of aseptic loosening of the tibial component and one because of infection. In addition, three knees were revised because of wear of the polyethylene tibial bearing. In the low contact stress group, two knees were revised because of instability requiring exchange of the polyethylene insert and one because of infection. The radiological analysis found no statistical difference in the incidence of radiolucent lines at the final review (Student’s We found no evidence of the superiority of one design over the other at long-term follow-up.
We examined whether a selective cyclooxygenase-2 (COX-2) inhibitor (celecoxib) was as effective as a non-selective inhibitor (ibuprofen) for the prevention of heterotopic ossification following total hip replacement. A total of 250 patients were randomised to receive celecoxib (200 mg b/d) or ibuprofen (400 mg t.d.s) for ten days after surgery. Anteroposterior radiographs of the pelvis were examined for heterotopic ossification three months after surgery. Of the 250 patients, 240 were available for assessment. Heterotopic ossification was more common in the ibuprofen group (none 40.7% (50), Brooker class I 46.3% (57), classes II and III 13.0% (16)) than in the celecoxib group (none 59.0% (69), Brooker class I 35.9% (42), classes II and III 5.1% (6), p = 0.002). Celecoxib was more effective than ibuprofen in preventing heterotopic bone formation after total hip replacement.
The outcome at ten years of 100 Freeman hip stems (Finsbury Orthopaedics, Leatherhead, United Kingdom) retaining the neck with a proximal hydroxyapatite coating in a series of 52 men (six bilateral) and 40 women (two bilateral), has been described previously. None required revision for aseptic loosening. We have extended the follow-up to 20 years with a minimum of 17 years. The mean age of the patients at total hip replacement was 58.9 years (19 to 84). Six patients were lost to follow-up, but were included up to their last clinical review. A total of 22 patients (22 hips) had died, all from causes unrelated to their surgery. There have been 43 re-operations for failure of the acetabular component. However, in 38 of these the stem was not revised since it remained stable and there was no associated osteolysis. Two of the revisions were for damage to the trunnion after fracture of a modular ceramic head, and in another two, removal of the femoral component was because of the preference of the surgeon. In all cases the femoral component was well fixed, but could be extracted at the time of acetabular revision. In one case both components were revised for deep infection. There has been one case of aseptic loosening of the stem which occurred at 14 years. This stem had migrated distally by 7.6 mm in ten years and 8.4 mm at the time of revision at which stage it was found to be rotationally loose. With hindsight this component had been undersized at implantation. The survivorship for the stem at 17 years with aseptic loosening as the endpoint was 98.6% (95% confidence interval 95.9 to 100) when 62 hips were at risk. All remaining stems had a satisfactory clinical and radiological outcome. The Freeman proximally hydroxyapatite-coated femoral component is therefore a dependable implant and its continued use can be recommended.
We produced large full-thickness articular cartilage defects in 33 rabbits in order to evaluate the effect of joint distraction and autologous culture-expanded bone-marrow-derived mesenchymal cell transplantation (ACBMT) at 12 weeks. After fixing the knee on a hinged external fixator, we resected the entire surface of the tibial plateau. We studied three groups: 1) with and without joint distraction; 2) with joint distraction and collagen gel, and 3) with joint distraction and ACBMT and collagen gel. The histological scores were significantly higher in the groups with ACBMT collagen gel (p <
0.05). The area of regenerated soft tissue was smaller in the group allowed to bear weight (p <
0.05). These findings suggest that the repair of large defects of cartilage can be enhanced by joint distraction, collagen gel and ACBMT.
We have tested the reliability of a recently reported classification system of hip morphology in adolescents with cerebral palsy in whom the triradiate cartilage was closed. The classification is a six-grade ordinal scale, based on the measurement of the migration percentage and an assessment of Shenton’s arch, deformity of the femoral head, acetabular deformity and pelvic obliquity. Four paediatric orthopaedic surgeons and four physiotherapists received training in the use of the classification which they applied to the assessment of 42 hip radiographs, read on two separate occasions. The inter- and intra-observer reliability was assessed using the intraclass correlation coefficient and found to be excellent, with it ranging from 0.88 to 0.94. The classification in our study was shown to be valid (based on migration percentage), and reliable. As a result we believe that it can now be used in studies describing the natural history of hip displacement in cerebral palsy, in outcome studies and in communication between clinicians.
We compared the orientation of the acetabular component obtained by a conventional manual technique with that using five different navigation systems. Three surgeons carried out five implantations of an acetabular component with each navigation system, as well as manually, using an anatomical model. The orientation of the acetabular component, including inclination and anteversion, and its position was determined using a co-ordinate measuring machine. The variation of the orientation of the acetabular component was higher in the conventional group compared with the navigated group. One experienced surgeon took significantly less time for the procedure. However, his placement of the component was no better than that of the less experienced surgeons. Significantly better inclination and anteversion (p <
0.001 for both) were obtained using navigation. These parameters were not significantly different between the surgeons when using the conventional technique (p = 0.966). The use of computer navigation helps a surgeon to orientate the acetabular component with less variation regarding inclination and anteversion.
Between May 1998 and May 2007 we carried out 50 Avon patellofemoral joint replacements in 32 patients with isolated patellofemoral osteoarthritis. There were no revisions in the first five years, giving a cumulative survival of 100% for those with a minimum follow-up of five years. The mean follow-up was 5.3 years (2.1 to 10.2). The median Oxford knee score was 30.5 (interquartile range 22.25 to 42.25). In patients with bilateral replacements the median Euroqol General health score was 50 which was significantly lower than that of 75 in those with a unilateral replacement (p = 0.047). The main complication was progression of disease, which was identified radiologically in 11 knees (22%). This highlights the need for accurate selection of patients. Our findings suggest that the Avon prosthesis survives well and gives a satisfactory functional outcome in the medium term.
We evaluated the survival of moulded monoblock and modular tibial components of the AGC total knee replacement in patients with rheumatoid arthritis. Between 1985 and 1995, 751 knees with this diagnosis were replaced at our institution. A total of 256 tibial components were of the moulded design and 495 of the modular design. The mean follow-up of the moulded subgroup was 9.6 years (0.5 to 14.7), and that of the modular group 7.0 years (0.1 to 14.7). The groups differed significantly from each other in Larsen grade, cementing of components and patellar resurfacing, but no statistically significant difference between the survival of the components was found (Log rank test, p = 0.91). The cumulative success rate of the moulded group was 96.8% (95% confidence interval 93.6% to 98.4%) at five years and 94.4% (95% confidence interval 90.4% to 96.7%) at ten years, and of the modular group 96.2% (95% confidence interval 94% to 97.6%) and 93.6% (95% confidence interval 89.7% to 96%), respectively. Revision was required in 37 total knee replacements, the main causes were infection, pain, loosening of the tibial component and patellar problems. Survival rates for both components were satisfactory.
We identified 42 patients who presented to our unit over a 27-year period with a secondary radiation-induced sarcoma of bone. We reviewed patient, tumour and treatment factors to identify those that affected outcome. The mean age of the patients at presentation was 45.6 years (10 to 84) and the mean latent interval between radiotherapy and diagnosis of the sarcoma was 17 years (4 to 50). The median dose of radiotherapy given was estimated at 50 Gy (mean 49; 20 to 66). There was no correlation between radiation dose and the time to development of a sarcoma. The pelvis was the most commonly affected site (14 patients (33%)). Breast cancer was the most common primary tumour (eight patients; 19%). Metastases were present at diagnosis of the sarcoma in nine patients (21.4%). Osteosarcoma was the most common diagnosis and occurred in 30 cases (71.4%). Treatment was by surgery and chemotherapy when indicated: 30 patients (71.4%) were treated with the intention to cure. The survival rate was 41% at five years for those treated with the intention to cure but in those treated palliatively the mean survival was only 8.8 months (2 to 22), and all had died by two years. The only factor found to be significant for survival was the ability to completely resect the tumour. Limb sarcomas had a better prognosis (66% survival at five years) than central ones (12% survival at five years) (p = 0.009). Radiation-induced sarcoma is a rare complication of radiotherapy. Both surgical and oncological treatment is likely to be compromised by the treatment received previously by the patient.
We conducted a randomised prospective study to evaluate the clinical and radiological results of a mobile- and fixed-bearing total knee replacement of similar design in 174 patients who had bilateral simultaneous knee replacement. The mean follow-up was for 5.6 years (5.2 to 6.1). The total knee score, pain score, functional score and range of movement were not statistically different (p >
0.05) between the two groups. Osteolysis was not seen in any knee in either group. Two knees (1%) in the mobile-bearing group required revision because of infection; none in the fixed-bearing group needed revision. Excellent results can be achieved with both mobile- and fixed-bearing prostheses of similar design at mid-term follow-up. We could demonstrate no significant clinical advantage for a mobile bearing.
In 1994, a register for cerebral palsy and a health-care programme were started in southern Sweden with the aim of preventing dislocation of the hip in children with cerebral palsy. It involved all children with cerebral palsy born in 1992 or later. None of the 206 affected children born between 1992 and 1997 has developed a dislocation following the introduction of the prevention programme. Another 48 children moved into the area and none developed any further dislocation. Of the 251 children with cerebral palsy, aged between five and 11 years, living in the area on January 1, 2003, only two had a dislocated hip. One boy had moved into the area at age of nine with a dislocation and a girl whose parents chose not to participate in the programme developed bilateral dislocation. One boy, whose condition was considered to be too poor for preventative surgery, developed a painful dislocation of the hip at the age of five years and died three years later. Eight of 103 children in a control group, consisting of all children with cerebral palsy living in the area between 1994 and 2002, and born between 1990 and 1991, developed a dislocation of the hip before the age of six years. The decreased incidence of dislocation after the introduction of the prevention programme was significant (p <
0.001). Dislocation of the hip in cerebral palsy remains a serious problem, and prevention is important. Our screening programme and early intervention when lateral displacement of the femoral head was detected appear to be successful.
We have carried out a radiostereometric study of 50 patients (54 knees) with osteoarthritis of the knee who were randomly allocated to receive a cemented or a hydroxyapatite-coated femoral component for total knee replacement. The patients were also stratified to receive one of three types of articulating surface (standard, rotating platform, Freeman-Samuelson (FS)1000) all based on the Freeman-Samuelson design. The tibial components were cemented in all cases. Radiostereometry was performed post-operatively and at 3, 12 and 24 months. The analysis was restricted to rotation of the femoral component over time. After two years, rotation of the femoral components in the transverse, longitudinal and sagittal planes did not differ between the cemented and the hydroxyapatite-coated implants (p = 0.2 to 0.9). In total knee replacements with a rotating platform, the femoral component tended to tilt more posteriorly than in the other two designs, regardless of the choice of fixation (cemented or hydroxyapatite-coated, p = 0.04). The standard version of the femoral component, whether cemented or hydroxyapatite-coated, rotated more into valgus than was observed with the rotating-platform and FS1000 designs (p = 0.005). The increased constraint provided by the FS1000 component did not appear to have any adverse effect on fixation of the femoral component.
We have reviewed the literature to establish the role of lateral retinacular release in the management of disorders of the extensor apparatus of the knee. The scientific evidence for intervention is explored and reports on outcome are discussed.
Osteochondroma is the most common benign bone tumour. The risk of sarcomatous change in an isolated lesion is approximately 1%. We report a case of an isolated osteochondroma which appeared benign on clinical and plain radiographic examination but routine histological analysis revealed non-Hodgkin’s lymphoma in the underlying bone. This association has not previously been reported and the case emphasises the importance of routine histological analysis, even if a lesion appears benign.
We compared the dynamic instability of 25 dysplastic hips in 25 patients using triaxial accelerometry before and one year after periacetabular osteotomy. We also evaluated the hips clinically using the Harris hip score and assessed acetabular orientation by radiography before surgery and after one year. The mean overall magnitude of acceleration was significantly reduced from 2.30 m/s This study suggests that periacetabular osteotomy provides pain relief, improves acetabular cover and reduces the dynamic instability in patients with dysplastic hips.
Arthritis of the hip in the young adult can be a disabling condition. Recent years have witnessed extensive research related to the management of this condition. This article reviews the current status with regard to aetiology, diagnosis and treatment of arthritis of the hip in the young adult.
Vancomycin-supplemented allografts provide biological restoration of bone stock and sound fixation with a low incidence of re-infection. Experimental incorporation of these grafts is similar to allografts without vancomycin. However, the underlying biology remains unknown. We report the first histological observations of vancomycin-supplemented impacted bone allografts in two reconstructions performed 14 and 20 months after revision surgery because of a periprosthetic fracture. Areas of active bone remodelling (creeping substitution), as well as calcified bone trabeculae and graft particles embedded in dense fibrous tissue, were observed with osteoid and fibroconnective tissue surrounding polymethylmethacrylate particles. These pathological findings are similar to those reported in allografts without vancomycin and support the hypothesis that high levels of vancomycin do not affect the incorporation of bone graft.
Our study was designed to compare the effect of indometacin with that of a placebo in reducing the incidence of heterotopic ossification in a prospective, randomised trial. A total of 121 patients with displaced fractures of the acetabulum treated by operation through a Kocher-Langenbeck approach was randomised to receive either indometacin (75 mg) sustained release, or a placebo once daily for six weeks. The extent of heterotopic ossification was evaluated on plain radiographs three months after operation. Significant ossification of Brooker grade III to IV occurred in nine of 59 patients (15.2%) in the indometacin group and 12 of 62 (19.4%) receiving the placebo. We were unable to demonstrate a statistically significant reduction in the incidence of severe heterotopic ossification with the use of indometacin when compared with a placebo (p = 0.722). Based on these results we cannot recommend the routine use of indometacin for prophylaxis against heterotopic ossification after isolated fractures of the acetabulum.
