Hip replacement is a very successful operation and the outcome is usually excellent. There are recognised complications that seem increasingly to give rise to litigation. This paper briefly examines some common scenarios where litigation may be pursued against hip surgeons. With appropriate record keeping, consenting and surgical care, the claim can be successfully defended if not avoided. We hope this short summary will help to highlight some common pitfalls. There is extensive literature available for detailed study.
Clinical success of total knee arthroplasty is correlated with correct orientation of the components. Controversy remains in the orthopaedic community as to whether the intramedullary or extramedullary tibial alignment guide is more accurate in the tibial cut. Is there any difference between intramedullary and extramedullary jigs to achieve better accuracy of the tibial components in total knee replacements? A retrospective study done on 100 patients during the time period 2007 to 2010. The 100 knee replacements were done by the same surgeon, where 50 patients had the intramedullary tibial alignment guide and the other 50 had the extramedullary one. The tibiofemoral angle was measured pre-operatively as well as post operatively, the tibial alignment angle was measured post operatively then the results were statistically analysed using the SPSS. There was no significant difference between both groups regarding the tibial alignment angles. Both techniques proved accurate in producing an acceptable post operative tibial component alignment angle. We recommend orthopaedic surgeons choose either technique knowing that accuracy levels are similar. The debate between intramedullary and extramedullary tibial cutting jigs/guides/ devices continues and most orthopaedic surgeons will use their preferred technique and will continue to achieve good post operative results as we have found in our centre. Our study is rare due to the fact we have a single surgeon performing both techniques, therefore controlling for any surgical experience or operating technique differences.
Supero-medial migration was seen in 27 (49%) of cases, demarcation without migration was seen in 18 cases (33%) and supero-lateral migration was seen in 7 (13%) cases. There were 2 (4%) socket fatigue fractures due to wear. There was 1 (2%) patient with a worn socket and no loosening. Reconstruction was achieved by impaction bone grafting alone in 25 cases, IBG and a block allograft in 9 cases, cement alone in 8 cases and IBG with a rim mesh in 4 cases. In cases where the supero-lateral margin of the socket was covered by host bone, failure always occurred by demarcation alone or in association with supero-medial migration. Rim defects significant enough to require reconstruction were seen in only 4 of these 45 patients (9%). Failure by supero-lateral migration was only seen in the cases of DDH where the socket was left uncovered or where the socket had fractured.
The pattern of socket failure can be reliably predicted from the original post-operative x-rays. Care should be taken to ensure adequate supero-lateral coverage in order that demarcation and migration leave an intact rim for reconstruction.
Recently, there has been a reluctance to perform hip arthrodesis. The number of patients requiring the conversion from hip arthrodesis to arthroplasty has also decreased. We present the functional results following conversion of hip arthrodesis to total hip arthroplasty at a specialist hip centre. 76 patients who underwent conversion of hip arthrodesis to total hip arthroplasty between 1963 and 2000 at the Centre for Hip Surgery, Wrightington Hospital, were included in this retrospective study. 9 patients died of unrelated causes and 7 patients were lost to follow up. The functional scoring was performed using the Merle d’Aubigné and Postel score. The mean age at the time of surgical hip arthrodesis was 16.7 years and at the time of conversion was 48.7 years. Back pain is the most common indication for the conversion. All the patients were pleased with the clinical outcome following conversion to Arthroplasty. 6 patients had postoperative complications. The mean Merle d’Aubigné and Postel score increased from 8.97 to 13.46 at the latest follow-up. The mean wear rate was 0.06 mm/year. Survival of hip arthroplasty was 92.78 % at 18 years.
To determine socket survivorship in DDH based on the severity of hip dysplasia, we carried out a retrospective study of 283 cemented total hip replacements carried out at Wrightington. The hips were classified according to the Crowe and Hartofilakidis classifications. Revision was used as the end point for prosthetic survivorship. The results were analysed statistically using SPSS for Windows The mean age at time of surgery was 42.6 years with a mean follow-up of 15.7 years. The acetabulum was grafted in 46 cases. The commonest cause for revision was aseptic loosening of the acetabular component (88.3%). 254 procedures were carried out through a transtrochanteric approach with a direct lateral approach used for the remaining mildly dysplastic hips. At 10 years 5.3% of dysplastic, 14.8% of low dislocation and 51.1 % of high dislocation hips were revised.. At 10years 6% of Crowe Type1, 8.5% of Type2, 25.5% of Type3 and 39.2% of Type4 hips were revised. At 20 years 24% of dysplastic, 45% of low dislocation and 88% of high dislocation hips were revised. At 20years 27.3% of Crowe Type1, 29.3% of Type2, 63.3% of Type3 and 84.4% of Type4 hips were revised. The 20 year survival of patients less than 50 years of age at the time of surgery was 61% as compared to 92% survival in patients more than 50 years of age. The mean age of patients in the revised group was 35 years as compared to 45 years in the non-revised group.
Patients undergoing total hip replacement (THR) often require further orthopaedic surgery including other primary lower limb joint replacements and revision surgery in their lifetime. We analysed the 10-year data of 552 patients who underwent primary total hip replacement between April 1991 and March 1992 at our institute. Data were available for all patients before the index operation. 77% of patients attended their 5-year review and 67% attended their 10-year review. 233 (42%) had had or subsequently had the opposite hip replaced. 30 patients (5%) had a knee replaced and 19 (3%) had both knees replaced. 4.4% underwent revision surgery.
Aseptic loosening is the commonest cause for revision of total hip replacements. Advances in technique have improved femoral fixation, but acetabular survival is unchanged. Little has been published about the pressures achieved during acetabular insertion. Using an experimental model, an acetabular cup was inserted into a model acetabulum using standard surgical technique. The pressures achieved under the centre of the cup, and also just beneath the superior flange were recorded over time via a data logger. The experiment was repeated for different insertion times, cup sizes and cement volumes. To reduce experimental error four runs for each constraint were performed. Complex pressure/time curves were produced for each run of the experiment. An average was then plotted. Peak and mean pressures were calculated from these curves. Central pressures were found to be similar to flange pressures, although pressure under the flange decayed more quickly as the cement cured. As long as the cup was inserted during the working phase cement then peak and mean pressures were similar. Use of a double cement mix with a 43mm cup showed a large increase in pressures over the single mix (peak 693 to 957mmHg, mean 297 to 485mmHg). Both were statistically significant (ANOVA: peak p=0.018, mean p=0.008). Peak pressure occurred with cup insertion, rather than with pre-pressurisation. The 47mm cup showed an increase of peak and mean pressures over the 43mm cup with a single mix (peak=800mmHg, mean=384mmHg). The pressures for the 47mm cup with a double mix were less than those of the 43mm cup with a double mix. Insertion of the cup without pre-pressurisation resulted in a rapid loss of pressure, and low mean pressures were achieved (double =262mmHg, single=80mmHg). Our experiment shows the need for pre-pressurisation, and that the timing of cup insertion is not critical as long as it is during the working phase of the cement. We have also shown an increase in pressure with a larger cup with a single mix of cement even though volumes were adequate to fill the space between cup and acetabulum. Interestingly we obtained significantly increased pressures with a smaller cup and a double volume of cement, this area needs further study.
Patients undergoing total hip replacement (THR) often require further orthopaedic surgery including other primary lower limb joint replacements and revision surgery in their lifetime. We analysed the 10-year data of 552 patients who underwent primary total hip replacement between April 1991 and March 1992 at our institute. Data was available for all patients before the index operation. 77% of patients attended their 5-year review and 67% attended their 10-year review. 233 (42%) had had or subsequently had the opposite hip replaced. 30 patients (5%) had a knee replaced and 19 (3%) had both knees replaced. 4.4% underwent revision surgery. Concluding, nearly half the total number of these patients will in due course require the opposite hip replaced. 13% will need another major joint surgery (ie revision or TKR). At £6138 for a primary THR and £8500 for revision THR, and the cost of radiographs (£60) and follow-up appointment (£60), the approximate cost implications on a conservative estimate are 13 million pounds. For a single surgeon undertaking 40 THRs in a single year the cost would be approximately £900,000. In addition, the surgeon in 10 years practice would create enough work to last him the rest of his working lifetime. These factors including cost implications and human resource requirements will have significant influence on future planning of health care trusts.