Revision after failed femoral components may
be technically demanding due to loss of peri-prosthetic bone. This retrospective
study evaluated the long-term results of femoral revision using
the cementless Wagner Self-Locking stem. Between 1992 and 1998,
68 consecutive hips in 66 patients underwent femoral revision using
this implant. A total of 25 patients died from unrelated causes
without further revision; the remaining 41 hips in 41 patients (12 men
and 29 women) with a mean age of 61 years (29 to 80) were reviewed
at a mean follow-up of 13.9 years (10.4 to 15.8). A transfemoral
approach was used in 32 hips. A total of five stems required further
revision because of infection in two, progressive subsidence in
two and recurrent dislocation in one. Four hips had dislocated and
eight stems had subsided ≥ 10 mm. The mean Harris hip score improved
from 33 points pre-operatively to 75 points at final follow-up (p
<
0.001). In all, 33 stems (91.7%) showed radiological signs
of stable bone fixation. The cumulative survival rates at 15.8 years
with femoral revision for any reason and for stem failure as the
endpoints were 92.0% (95% confidence interval (CI) 86.0% to 98.4%)
and 96.6% (95% CI 92.2% to 100%), respectively. The survivorship
with revision and ≥ 10 mm migration of the stem as the endpoint
was 83.6% (95% CI 76.6% to 91.4%). This study shows quite good survival and moderate clinical outcome
when using a monoblock tapered titanium stem for supporting the
regeneration of bone in complex revision hip surgery.
Mechanical failure because of wear or fracture of the polyethylene tibial post in posteriorly-stabilised total knee replacements has been extensively described. In this study of 12 patients with a clinically and radiologically successful NexGen LPS posteriorly-stabilised prosthesis impingement of the anterior tibial post was evaluated in vivo in three dimensions during gait using radiologically-based image-matching techniques. Impingement was observed in all images of the patients during the stance phase, although the NexGen LPS was designed to accommodate 14° of hyperextension of the component before impingement occurred. Impingement arises as a result of posterior translation of the femur during the stance phase. Further attention must therefore be given to the configuration of the anterior portion of the femoral component and the polyethylene post when designing posteriorly-stabilised total knee replacements.
A modular layered acetabular component (metal-polyethylene-ceramic) was developed in Japan for use in alumina ceramic-on-ceramic total hip replacement. Between May 1999 and July 2000, we performed 35 alumina ceramic-on-ceramic total hip replacements in 30 consecutive patients, using this layered component and evaluated the clinical and radiological results over a mean follow-up of 5.8 years (5 to 6.5). A total of six hips underwent revision, one for infection, two for dislocation with loosening of the acetabular component, two for alumina liner fractures and one for component dissociation with pelvic osteolysis. There were no fractures of the ceramic heads, and no loosening of the femoral or acetabular component in the unrevised hips was seen at final follow-up. Osteolysis was not observed in any of the unrevised hips. The survivorship analysis at six years after surgery was 83%. The layered acetabular component in our experience, has poor durability because of unexpected mechanical failures including alumina liner fracture and component dissociation.
There have been few reports in the literature of total elbow arthroplasty extending beyond 10 to 15 years. We reviewed 40 patients (41 elbows) with a mean age of 56 years (19 to 83) who had undergone a Coonrad/Coonrad-Morrey elbow arthroplasty by one surgeon for various diagnoses between 1974 and 1994. Surgical selection excluded patients with previous elbow infection or who refused to accept a sedentary level of elbow activity postoperatively. Objective data were collected from charts, radiographs, clinical photographs and supplemented by the referring orthopaedic surgeons’ records and radiographs if health or distance prevented a patient from returning for final review. Subjective outcome was defined by patient satisfaction. Of the 41 elbows, 21 were functional between 10 and 14 years after operation, ten between 15 and 19 years and ten between 20 and 31 years. There were 14 complications and 13 revisions, but no cases of acute infection, or permanent removal of any implant.
We reviewed 123 second-generation uncemented total hip replacements performed on 115 patients by a single surgeon between 1993 and 1994. The acetabular component used in all cases was a fully porous-coated threaded hemispheric titanium shell (T-Tap ST) with a calcium ion stearate-free, isostatically compression-moulded polyethylene liner. The titanium femoral component used was a Taperloc with a reduced distal stem. No patient was lost to follow-up. Complete clinical and radiological follow-up was obtained for all 123 hips at a mean of 14 years (12 to 16). One femoral component was revised after a fracture, and three acetabular components for aseptic loosening. No additional femoral or acetabular components were judged loose by radiological criteria. Mild proximal femoral osteolysis was identified in two hips and minor acetabular osteolysis was present in four. The mean rate of penetration of the femoral head was 0.036 mm/year (0.000 to 0.227). These findings suggest that refinements in component design may be associated with excellent long-term fixation in cementless primary total hip replacement.
Isolated patellofemoral osteoarthritis can be a disabling disease. When conservative treatment fails, surgical options can be unpredictable and may be considered too aggressive for middle-aged and active people. We analysed the clinical and radiological results of a new coronal osteotomy involving thinning of the patella in a selected group of patients with isolated patellofemoral osteoarthritis. Since 1991, 31 patients (35 knees) have been treated, of whom 34 were available for follow-up at a mean of 9.1 years. The Knee Society Score, the Patellar score and the Short-form-36 questionnaire were used for clinical evaluation. We also examined the radiological features to confirm bone consolidation and assess the progression of osteoarthritis. A significant improvement in the functional scores and radiological parameters was noted. All patients except one were satisfied with the operation. Radiological progression of the patellofemoral osteoarthritis was slowed but radiological femorotibial osteoarthritis progressed in 23 (65%) cases, with a total knee replacement becoming necessary in four cases without technical problems in resurfacing the patella. We compared the results with other forms of surgical treatment reported in the literature. This treatment offers good clinical and radiological results, presenting an alternative method of managing patellofemoral osteoarthritis.
We describe a cohort of patients with a high rate of mid-term failure following Kinemax Plus total knee replacement inserted between 1998 and 2001. This implant has been recorded as having a survival rate of 96% at ten years. However, in our series the survival rate was 75% at nine years. This was also significantly lower than that of subsequent consecutive series of PFC Sigma knee replacements performed by the same surgeon. No differences were found in the clinical and radiological parameters between the two groups. At revision the most striking finding was polyethylene wear. An independent analysis of the polyethylene components was therefore undertaken. Scanning electron microscopy revealed type 2 fusion defects in the ultra-high molecular weight polyethylene (UHMWPE), which indicated incomplete boundary fusion. Other abnormalities consistent with weak UHMWPE particle interface strength were present in both the explanted inserts and in unused inserts from the same period. We consider that these type 2 fusion defects are the cause of the early failure of the Kinemax implants. This may represent a manufacturing defect resulting in a form of programmed polyethylene failure.
We analysed at a mean follow-up of 7.25 years the clinical and radiological outcome of 117 patients (125 knees) who had undergone a primary, cemented, modular Freeman-Samuelson total knee replacement. While the tibial and femoral components were cemented, the patellar component was uncemented. A surface-cementing technique was used to secure the tibial components. A total of 82 knees was available for radiological assessment. Radiolucent lines were seen in 41 knees (50%) and osteolytic lesions were seen in 13 knees (16%). Asymptomatic, rotational loosening of the patellar implant was seen in four patients and osteolysis was more common in patients with a patellar resurfacing. Functional outcome scores were available for 41 patients (41 knees, 35%) and the mean Western Ontario McMasters Universities score was 77.5 (