Hip and Knee Revisions

Hip and Knee Revisions Summary Wirral performs a greater number of hip revisions than knee revisions; the total cost for both equates to more than 900,000. Hip and knee revisions are a more complicated and costly procedure than primary operations; evidence suggests that they are effective in reducing pain and improving function although not to the extent of primary replacements. This paper makes a number of recommendations following a review of the evidence. Key points and recommendations include: Wirral is performing poorly regarding the length of hospital stay following knee revision, at an average of 19.2 days per operation compared to the national average of 12 days. Wirral could save a considerable amount of money if the number of bed days was reduced to the national average In 2006/07 Wirral performed more hip revisions (total of 103) than would be expected when compared to the number of primary hip replacement operations (total of 373). Hip revisions therefore represent 21.6% of the total operations on hip replacements in Wirral Patient selection for revision surgery is essential to ensure good results; the exact cause of failure should be established so that appropriate treatment can be given Early failure rates from primary procedures are from infections; trust s should monitor their infection rates and compare with national standards Mechanical failure is one of the main causes for revisions over the longer term; durable primary implants should be used and supported by evidence based surgical practice. Trusts should ensure they are adhering to the NICE guidance in relation to hip and knee replacements. This paper should be read in conjunction with the primary hip and primary knee replacement reviews. Background Hip and knee revisions are performed following failed prostheses from primary hip and knee replacements. Most hip and knee replacements last up to 10 years; many then begin to fail after this period (BAO and BASK, 2001; BAO, 2006). [Separate reviews have been written on primary hip and knee replacements] According to the data on the National Joint Registry (NJR) for England and Wales there were, as a proportion, considerably more revision operations performed on hips than knees in 2005. The number of hip revision operations registered on the NJR was 5,769, which represents 9.4% of the total operations on hip replacements whilst the number of knee revisions registered was 2,824, representing 4.6% of the total operations on knee replacements. Guidelines There are no specific guidelines identified for hip and knee revisions. Good practice guides for hip and knee replacements have been produced by the British Orthopaedic Association (BOA) (2006) and British Orthopaedic Association/British Association for Surgery of the Knee (2001) respectively, which provides recommendations regarding the long term follow-up after surgery to reduce the risk of failure and subsequent need for revision surgery. The key points related to revisions for both hips and knees are summarised in table 1 below: Table 1: Summary of BOA guidance on long term follow-up following primary hip and knee replacements Public Health Intelligence Team Page 1 of 6

LONG TERM FOLLOW UP OF PATIENTS Some implants fail before ten years and more thereafter. Failure from aseptic loosening of the prosthesis is often silent; the patient may not complain. Regular follow-up with X-ray examination identifies the patient at risk of failure. For best practice patients should be followed up clinically and radiologically in the longer term. Minimal requirements include; history of complaints; clinical examination and antero-posterior (AP) and lateral X-rays at one, five and each subsequent five years after operation. Revision procedure should be planned and performed before massive bone destruction occurs; delay may result in the need for much more extensive surgery which is more demanding of resources and has greater risk of failure. Follow-up using questionnaires with X-ray examination by non-medically qualified clinicians is used in some centres. This may permit more efficient use of consultant time. It is recommended that part of the contractual agreement with purchasers/commissioners is to require follow-up to identify premature failure. Situation in Wirral In Wirral a total of 103 hip revision procedures and 17 knee revision procedures were carried out between April 2006 and March 2007, at a total cost of 779,000 and 128,000 respectively. This equates to over 7500 per operation for a hip or knee revision. According to data provided by Wirral PCT s Information Team, in 2005/06 Wirral s procedure rate for hip and knee revisions combined was slightly but not significantly below the North West average. Figure 1 displays the directly standardised rates (DSR) for hip and knee revisions per 100,000 of the population in the North West region for 2005/06. Figure 1: Directly Standardised Rate per 100,000 population for Hip and Knee Revisions by PCT 2005/06 North West Warrington PCT Halton and St. Helens PCT Central Lancashire PCT Sefton PCT Central and Eastern Cheshire PCT Oldham PCT Western Cheshire PCT Knowsley PCT Tameside and Glossop PCT Ashton Leigh and Wigan PCT PCT East Lancashire PCT Blackburn with Darwen PCT Wirral PCT Cumbria PCT Heywood Middleton and Rochdale PCT Trafford PCT Bolton PCT Salford PCT Manchester PCT Stockport PCT North Lancashire PCT Liverpool PCT Bury PCT Blackpool PCT 0 5 10 15 20 25 30 35 40 45 50 DSR/100,000 Wirral PCT s DSR for hip and knee revision was 31.23/100,000 compared to the North West DSR of 32.33/100,000. In 2006/07 there were 103 hip revision procedures carried out in Wirral, compared to 373 primary hip replacements; hip revisions therefore represent 21.6% of the total operations on hip replacements in Wirral. This is significantly higher than the national Public Health Intelligence Team Page 2 of 6

average of 9.4%. The number of knee revision procedures carried out in 2006/07 was 17 compared to 561 primary knee operations; this represents 2.9% of the total operations on knee replacements in Wirral. This is lower than the national average of 4.6%. Croydon PCT and the London Public Health Observatory estimate that between 15%- 30% cost savings could be made through restricting access to knee surgery (South West London Public Health Network, 2006). These calculations were based on value judgements drawing on clinical evidence, experiences elsewhere and analyses of diagnosis data to estimate the proportion of unavoidable procedures. In Wirral, between 2006/07 it is estimated that these cost savings, based on the above calculations, would equate to between 136,050 and 272,100. However, it is not possible to make these cost savings if there is no detailed information or evidence provided that clearly demonstrates how these cost savings can be achieved. Nationally the average length of hospital stay for hip revisions is 16.5 days; Wirral is performing slightly better than the national average with the average length of stay at 15.9 days. This is in contrast to the length of stay following the primary procedure where Wirral is performing poorly against the national average and lies within the bottom 25% of PCTs; average length of stay is 13.9 days compared to the national average of 10 days. Wirral is also not performing well with regards to hospital stay for knee revisions; the national average is 12 days, whilst Wirral s average length of stay is 19.2 days. This is in contrast to the length of stay following the primary procedure where Wirral is performing slightly better than the national average (8.7 days compared to 9.7 days). Considerable savings could be made if Wirral could reduce the length of hospital stay for knee revisions; each bed day is estimated to cost the PCT almost 400 ( 393). Evidence base for hip and knee revisions There are no cochrane reviews on the effectiveness of hip and knee revisions. It is difficult to directly compare studies on hip and knee revisions due to differences between the studies, such as effectiveness of different implants, surgical techniques, aetiology etc. The following section summarises the main evidence for knee and hip revisions: Knees: Evidence reviews have found that knee revision surgery is effective in improving function and relieving pain following a failed total knee replacement (Khaled et al. 2003; Callaghan et al. 1994) The widely reported causes for failure of the primary knee replacement and resulting knee revision surgery are, asceptic loosening, instability and infection (Gio et al. 2004; Sierra et al. 2004; Sharkey et al. 2002). There is evidence to suggest that infection and instability of the prosthesis are two of the leading causes for revisions done less than 2 years after the initial primary procedure; aseptic loosening and mechanical failures have also been identified as key causes for revision over the longer term (greater than 2 years) (Gioe et al. 2004; Sharkey et al. 2002). Patients whose condition has not been radiographically or clinically determined are less likely to have a good result from knee revision (Bare, J. et al. 2006; Brown et al. 2006; Sharkey et al. 2002). Clinical research has identified a higher rate of failure following revision surgery than primary knee replacement; revision patients for example are more Public Health Intelligence Team Page 3 of 6

susceptible to infections after the procedure (Sierra et al. 2004; Saleh et al. 2002; Goldberg et al. 1988) A study that was conducted by a team at Arrowe Park Hospital assessed and compared outcomes of primary and revision knee surgery performed by a single surgeon at the hospital. The findings indicated that in terms of patient perceived outcomes, revision total knee replacement leads to as great an improvement as primary replacement (Hartley et al. 2002). Hips: Reviews have identified hip revision as an effective treatment for failed hip prosthesis (Bandolier, 2004; Saleh et al. 2003) The causes for failure of the primary hip replacement and resulting hip revision surgery have been reported as asceptic loosening, instability and infection (Ulrich et al. 2007; Clohisy et al. 2004; Dawson et al. 2003); this closely reflects the causes for revision following primary knee replacement. Revisions are a more complicated procedure to perform than primary hip replacements and have higher failure rates (NAO, 2000). A systematic review of the literature identified that revision hip replacement surgery does not provide as a great an improvement as primary surgery, with regards to physical function and overall health perception (Ethegen et al. 2004). However, patient satisfaction, following revision surgery has still been reported as high (75% of patients happy with the procedure and reported less pain at year one) (Dawson et al. 2001). According to a Health technology Assessment review, the price, revision rate and age of the patient should be taken into account to ensure the cost effectiveness of the prostheses. For example, for an older person (70 years and above) it is generally more cost effective to use a low price prosthesis, even with a very low revision rate; whilst in a younger person (40 years), prostheses with high prices and low revision rates can be more cost effective (Faulkner et al. 1998). Conclusion/recommendations The percentage of patients who need early or late revisions after total knee replacement is relatively small (17 procedures in 2006/07). However this small percentage of failures translates into considerable cost ( 128,000 in 2006/07). The number of knee revision procedures represents 2.9% of the total operations on knee replacements in Wirral. This is lower than the national average of 4.6%. Wirral is therefore performing fewer revisions than would be expected for the number of primary knee replacement operations. Wirral is performing poorly regarding the length of hospital stay following knee revision, at an average of 19.2 days per operation compared to the national average of 12 days. This is in contrast to the length of stay following the primary procedure where Wirral is performing slightly better than the national. Wirral could save a considerable amount of money if the number of bed days was reduced to the national average (on average up to 2750 per patient). The number of patients having hip revisions is considerably higher than that for knees (103 procedures in 2006/07 at a cost of 779,000). Hip revision procedures represent 21.6% of the total operations on hip replacements in Wirral. This is significantly higher than the national average of 9.4%. Wirral is therefore performing more revisions than would be expected for the number of primary hip replacement operations. Public Health Intelligence Team Page 4 of 6

Wirral is performing slightly better than the national average regarding length of hospital stay following hip revision; average of length of stay is 15.9 days compared to the national average of 16.5 days. This is in contrast to the length of stay following the primary procedure where Wirral is performing poorly against the national average and lies within the bottom 25% of PCTs. Cost for revision surgery is higher than the cost of primary surgery. Revision surgery is estimated to cost over 7500 for hip or knees, whilst primary surgery costs approximately 2000 less, at an average of 5134 for hips and 5524 for knees. Length of hospital stay is also greater following revision surgery. Patient selection is essential in achieving good results; the aetiology should be established through careful pre-operative analysis to ensure the cause of the failure is known so that appropriate treatment can be given. Early failure rates after primary hip and knee replacements are frequently related to infection. Trusts should monitor their infection rate and compare with national standards. As mechanical failure is one of the reasons for revisions over the longer term it is crucial to ensure that durable primary implants are used, which have a sound evidence base and are supported by evidence based surgical practice. Trusts should ensure that they are adhering to NICE guidance in relation to hip and knee replacements (NICE 2006; 2005a; 2005b; 2001a; 2001b; 2000). The recommendations made in the primary hip and primary knee replacements reviews should also be considered. References Bare, J. et al. (2006). Preoperative evaluations in Revision Total Knee Arthroplasty. Clinical Orthopaedics & Related Research, 446, p.40-44. Brown, E. C. et al. (2006). The painful total knee arthroplasty: Diagnosis and management. Orthopaedics, 29 (2), p.129-136. Callaghan, C. M. et al (1994). Patient outcomes following tricompartmental total knee replacement. A Meta-analysis. JAMA. 271, p.1349-1357. Dawson, J. et al. (2001) Evidence for the validity of a patient-based instrument for assessment of outcome after revision hip replacement. Journal of Bone and Joint Surgery, 83 (8), p.1125-1129. Ethegen, O. et al. (2004). Health-Related Quality of Life in Total Hip and Total Knee Arthroplasty: A qualitative and systematic review of the literature. Journal of Bone and Joint Surgery, 86 (5), p.963-974. Faulkner, A. et al. (1998). Effectiveness of hip prostheses in primary total hip replacement: a critical review of evidence and an economic model. Health Technology Assessment, 2 (6). Goldberg, V. N. et al (1988). The results of revision total knee arthroplasty. Clinical Orthopaedics and Related Research, 226, p.86-92. Gio, T. J. et al. (2004). Why are total knee replacements revised? Analysis of Early Revision in a Community Knee Implant Registry. Clinical Orthopaedics and Related Research, 428, p.100-106. Public Health Intelligence Team Page 5 of 6

Khaled, J. S et al. (2003). Current status of revision total knee arthroplasty: How do we assess results? Journal of Bone and Joint Surgery, 85, p. 18-20. NAO (2000). Hip replacements: Getting it right first time. London: The Stationary Office. NICE (2006). Single mini-incision hip replacement. Interventional Procedure Guidance 152. NICE Publication. NICE (2005a). Minimally invasive two-incision surgery for total hip replacement. Interventional Procedure Guidance 112. Nice Publication. NICE (2005b). Mini-incision surgery for total knee replacement. Interventional Procedure Guidance 117. NICE. NICE (2001a). Referral advice: A guide to appropriate referral from general to specialist services. NICE. NICE (2001b). Referral Advice: A guide to appropriate referral from general to specialist services. NICE. NICE (2000). Guidance on the Selection of Prostheses for Primary Total Hip Replacement. Technology Appraisal Guidance No.2. NICE Saleh, K. J. et al (2003). Modes of failure and preoperative failure. The Journal of Bones and Joint Surgery, 85-A (suppl 1), p.21-25. Saleh, K. J. et al. (2002). Functional outcome after total knee arthroplasty revision: a metaanalysis. Journal of Arthroplasty, 17, p.967-977. Sharkey, P. F. et al. (2002). Why are total knee arthroplasties failing today? Clinical Orthopaedics and Related Research, 404, p.7-13. Sierra. R. J. et al. (2004). Reoperations after 3200 revision TKAs: rates, etiology and lessons learned. Clinical Orthopaedics and Related Research, 425, p.200-206. South West London Public Health Network (2006). Effective Commissioning initiative. http://www.lho.org.uk/viewresource.aspx?id=11206. Ulrich, S. D. et al. (2007). Total hip arthroplasties: What are the reasons for revision? International Orthopaedics, April 19. Public Health Intelligence Team Page 6 of 6