Thirty cemented THRs and 13 hybrid THRs were performed through trochanteric osteotomy approach (23), posterior approach (17), Hardinge approach (2) and anterior approach (1). In the cemented group there were 3 cases of superficial wound discharges, 1 recurrent dislocation, 1 complete femoral nerve palsy, 2 cases of neuropraxia and 1 case with persistent hip pain but no cases of infection. In the hybrid group there was one case of partial femoral nerve palsy. None of the patients has undergone any revision surgery till the latest follow up. Radiologically only one case showed aseptic loosening in both femoral and acetabular components, which is not revised as the patient is asymptomatic.
Above a certain threshold, distal migration may predict medium-to-long-term failure of “shape-closed” (collared, textured) stems. However, no such threshold exists for “force-closed” stems, and these may continue to migrate after 3 years. We believe that the tendency towards stabilisation 2–3 years postoperatively could be the best predictor of good long-term performance.
In situ fixation of mild slips of the slipped capital femoral epiphysis (SCFE) is a safe and reliable method of treatment. Hardware failure and fractures are reported at the time of pin retrieval. Difficulty in removing these pins is well reported. Major problems can be expected when arthroplasty is necessary years later, if the pins are still inside the proximal femur. Hence we have come up with a novel technique to remove these pins during Primary Total hip arthroplasty. The hip is exposed through posterior approach, dislocated and the neck is then cut at the usual site. It is then segmented in both sagittal and coronal planes into approximately eight to ten pieces and removed piecemeal. The pins are thus exposed, cleared of any bony debris and hammered retrograde. By using our simple and novel technique to remove these pins we feel it avoids unnecessary trauma to the outer cortex of femur and also reduces the operating time significantly.
When component failure was used as the endpoint, the survivorship of the acetabular component was 78% at 15 years (CI, 64% to 87%), 66% at 20 years (CI, 48% to 80%), 43% at 25 years (CI, 21% to 62%) and 12% at 30 years (CI, 2% to 32%). The survival of the femoral component was 76% at 15 years (CI, 62% to 85%), 67% at 20 years (CI, 48% to 80%), 47% at 25 years (CI, 25% to 67%) and 7% at 30 years (CI, 1% to 26%). The survival of both components was 74% at 15 years (CI, 59% to 83%), 64% at 20 years (CI, 44% to 78%), 43% at 25 years (CI, 20% to 64%) and 7% at 30 years (CI, 1% to 27%).
(Previous report: Charnley low-friction arthroplasty for Paget’s disease of the hip. J Arthroplasty. 2000 Feb;15(2):210–9).
Total hip replacement is a successful and reliable procedure for the relief of pain, but the results achieved have been reported to be less successful in younger patients who tend to be relatively more active and place greater demands on prostheses than older patients. Between 1966 and 1978, 226 Charnley low friction arthroplasties (LFAs) were implanted in young patients with an average age at operation of 31.7 years. Initial results were presented at an average of 19.7 years. We have performed a further retrospective analysis of this cohort at 10 years on from the time of data collection of the original study. Of the original cohort, 112 patients are alive and either under follow-up at our hospital or have been traced to other hospitals. 16 have been lost to follow-up. Mean follow-up was 26.4 years. At the time of final follow-up or death, rate of aseptic loosening of the stem was approximately 80%. Acetabular components proved to be less successful with less than 60% remaining well fixed. Differences in survival were apparent between subgroups with differing original pathology with stem survival greater in those with DDH as opposed to rheumatoid or degenerative arthritis and the opposite being true for socket survival. This study adds to the available knowledge of the longevity of cemented total hip replacement as performed with unsophisticated cementation techniques and how it may perform in differing patients groups.
A secure bone cement interface between the acetabulum and the cement mantle of the hip socket is an important requirement for the long-term success of a cemented hip arthroplasty. Cement pressurisation after bone bed cleaning enables cement to penetrate interstices of cancellous bone forming a superior fixation strength. We designed an in-vitro experiment to evaluate the performance of the Exeter, Depuy T-handle and a plunger-type pressurisers using two parameters: cement penetration and cement pressurisation. The deformation of the flexible pressure head of the DePuy model produced a cement mantle, which is thick at the pole but tapered at its rim and variable in the amount of penetration produced (range 2–8mm) for an estimated similar force. Pressures of up to 60KPa were generated throughout the model acetabulum. The Exeter pressuriser was found to produce cement mantles more compatible with a socket. However, the test results show a wide variation in cement penetration occurring for what was estimated to be a similar applied force (3mm to 9mm at the pole and 5mm to 9mm at the rim). It was also shown to have the disadvantage of causing widely dissimilar pressures at the pole and the rim. The plunger protrusion required to produce 5mm cement penetration was found to be 7.5mm. Since this protrusion can be monitored and controlled by the operator, a cement intrusion of 5mm +/−1mm was found to be reproducible with the plunger-type device. The maximum variation in intrusion between rim and pole was 1 mm. Maximin pressures of 70KPa were generated. We have presented experimental evidence that suggests that a plunger type of acetabular cement pressuriser may provide a more consistently reproducible level of pressurisation leading to optimal cement penetration.
3610 primary and revision total knee replacements were performed at our hospital between 1969 and 1995. We conducted a survivorship analysis of 3234 primary total knee replacements to construct life tables and calculate survival curves. Each knee replacement was entered once only. Revision was defined as the end point. Data was collected both from patient records and by postal questionnaire. Eight types of knee prostheses were evaluated with best-case and worst-case scenarios compared over a 5, 10 and 15 year period. The evidence suggests that certain types of prosthesis are more liable than others to fail or to fail early. The “Condylar type devices” which include the Total Condylar, Press Fit Condylar (PFC), Kinematic, Kinemax and Anatomic Modular Knee (AMK) have very similar survivorship curves and in the main have performed well up to a 10 year period. The LCS mobile bearing knee performed extremely well at 5 years. The Attenborough knee had an inferior result while the Load Angle Inlay (LAI) which was a very early resurfacing arthroplasty had the poorest results in terms of survivorship.
Restoration of the mechanical axis is thought to be a critical factor in determining the Outcome of knee replacement surgery. There is strong theoretical evidence that reproduction of this axis improves mechanical loading and hence longevity of the implant. Clinical studies are small in number. Per-operative use of intra-and-extra-medullary alignment jigs help to determine the distal femoral and proximal tibial cuts. Studies have shown large margins of error using the standard jigs provided with most total knee replacement systems. On this basis computer assisted guidance systems are being introduced such as Orthopilot and BrainLab. These systems allow more accurate placement of the bony cuts and hence improve overall lower limb alignment. No study has shown conclusively that accurately reproducing the mechanical axis of the lower limb improves survivorship of the implant. Prior to investing in these systems we felt it would be prudent to investigate how critical reproduction of the mechanical axis was in the primary total knee replacement. We assessed 100 primary kinematic total knee replacements performed in 1990. All case notes were reviewed looking for basic demographics, pathology and clinical outcome. All cases had a long leg film weight-bearing alignment film taken post-operatively. These were digitised and then analysed using Design CAD 97 software and from this the mechanical axis calculated. Using these data the patients were divided into two groups. The first were within 3 degrees varus/valgus of the mechanical axis. The second were outside this range. These two groups were then correlated to clinical outcome.
Fifty-seven revision total knee arthroplasties were performed in our hospital using the TC3 system between 1995 and 1997. Twelve patients died. Forty-five patients were followed up for an average of 5.6 years (range 4 – 7 years). No patients were lost to follow-up. All patients were clinically and radiologically evaluated. A postal patient satisfaction questionnaire was completed. Two patients were revised; one for infection and one for instability. Survivorship using revision as the end point was 93.3% at 7 years. Indications for revision were infection (4;9%), instability (38;84%), pain and stiffness (3;7%). 32 (71%) patients were satisfied with their outcome, 7 (16%) were noncommittal and 6 (13%) were disappointed at 5 years. We have analysed the 13 dissatisfied patients and highlight the lessons learned. Pain and stiffness are not good indications for revision; insert thickness of more than 17.5mm is suggestive of elevation of the joint-line; instead the femoral component should be distalised; step wedges should be used in preference to angular wedges; Always long stem the tibial implant if augments are used; stems should be canal filling with adequate grip on the diaphysis. We suggest the above lessons we have learned from our initial revision arthroplasty learning curve may correlate to the clinical outcome of this small group of dissatisfied patients.