In Reply

Abstract

We thank Dr Vendittoli and his coauthors for their considered response to our Editorial [1Crawford R.W. Ranawat C.S. Rothman R.H. Metal on metal: is it worth the risk?.J Arthroplasty. 2010; 25Google Scholar]. First, the authors suggest that we need to review some key peer-reviewed articles to look at the success of resurfacing and metal-on-metal hip arthroplasties. A valid point that needs to be made is that both are review articles and not individually published series [2Simmin A. Beaulé P.E. Campbell P.A. Current concepts review: metal on metal hip resurfacing.J Bone Joint Surg. 2008; 90: 637Crossref PubMed Scopus (195) Google Scholar, 3Campbell P. Shen F.W. McKellop H. Biologic and tribologic considerations of alternative bearing surfaces.Clin Orthop. 2004; : 98Crossref PubMed Scopus (94) Google Scholar]. One article is about resurfacing rather than conventional total hip arthroplasty. Resurfacing was not specifically addressed in our editorial, but we welcome the chance to widen the discussion. We recognize that there are some articles showing good survivorship of resurfacing. However, in the overall operating surgeons' hands, the results of resurfacing are not as good as conventional total hip arthroplasty. As previously stated, this is highlighted by the Australian and UK registries [4AOA Australian Orthopaedic Association National Joint Replacement Registry annual report. AOA, Adelaide2008Google Scholar, 5The National Joint Registry 5th annual report. Hemel Hempstead: National Joint Registry for England and Wales; 2009.Google Scholar] that state that hip resurfacing shows the highest revision rates in early and at midterm results. Two articles by Dr Beaulé, a coauthor on the letter to the editor to which we reply, serve to reinforce this point. The first article looks at causes of early failure in a multicenter clinical trial of hip resurfacing [6Kim P.R. Beaulé P.E. Laflamme F.Y. et al.Causes of early failure in a multicentre clinical trial of hip resurfacing.J Arthroplasty. 2008; 23Google Scholar]. Dr Beaulé and his coauthors report a 7% revision rate for resurfacing in 200 patients by 2 years. The patients who failed were younger and heavier. This high failure rate was put down to a learning curve. A learning curve to a surgeon is a failure to a patient. An operation that has a long learning curve and is difficult needs to be placed in context. If every operating surgeon goes through a long learning curve, many patients will have adverse outcomes. It would appear from the published literature and from the article by Dr Beaulé that resurfacing is a difficult operation that should not be done in the general orthopedic community.We also refer to a second article by Dr Beaulé et al looking at the Canadian Academic experience with metal-on-metal hip resurfacing. In this study, a 3.2% failure rate at 2 years and 1.6% femoral neck fracture rate was reported. Again, this is a high failure rate so early in the implantation of the prosthesis. The contributing surgeons are all experts in arthroplasty and are performing high volumes of hip arthroplasty. Such a high failure rate in the very best hands is concerning. Furthermore, the authors state that their results are better than in previous multicenter trials. This article highlights that hip resurfacing has very high failure rates when performed in the general orthopedic surgeon's hands. Even in the very best hands it has a high failure rate!Next, we would like to review another article by Dr Beaulé in 2010 looking at the incidence of groin pain after metal-on-metal hip resurfacing [7O'Neill M. Beaulé P.E. Bin Nasser A. et al.Canadian academic experience with metal-on-metal hip resurfacing.Bull NYU Hosp Jt Dis. 2009; : 67Google Scholar]. In this article, Dr Beaulé reviewed hip resurfacing in young patients in a single institution. He reported that 18% of the patients had significant groin pain, of which 10% of the total number of patients said that the pain limited their activities of daily living. Also, 10% of patients required ongoing medication for pain. One should question if it is reasonable to perform an operation that has an 18% incidence of ongoing pain requiring either analgesia or modification to activities in a young active population. The authors conclude that their rate of groin pain is between 4 and 50 times higher than previously reported groin pain in patients undergoing total hip arthroplasties. This article highlights yet another unexpected clinical problem associated with metal on metal bearings. It is not clear whether metal-on-metal or resurfacing is the cause of this incidence but the clinical conclusion is in no doubt.Under subheading no. 2, Dr Vendittoli et al discuss the issue of a learning curve, modified surgical technique and ‘unproven' metal on metal devices. They highlight a large number of metal-on-metal implants that they considered as unacceptable. It is reasonable that we continue to innovate in total hip arthroplasty but at what cost? Metal-on-metal bearings either in a total hip or a resurfacing do not show any clinical advantage [8Bin Nasser A. Beaulé P.E. O'Neill M. et al.Incidence of groin pain after metal-on-metal resurfacing.Clin Orthop Relat Res. 2010; 468: 392Crossref PubMed Scopus (54) Google Scholar]. Instead they are producing a new series of complications such as those highlighted above with reference to groin pain. We see no reason to change our position that metal on metal bearings should be ‘used with great caution if at all'. We thank Dr Vendittoli and his coauthors for their considered response to our Editorial [1Crawford R.W. Ranawat C.S. Rothman R.H. Metal on metal: is it worth the risk?.J Arthroplasty. 2010; 25Google Scholar]. First, the authors suggest that we need to review some key peer-reviewed articles to look at the success of resurfacing and metal-on-metal hip arthroplasties. A valid point that needs to be made is that both are review articles and not individually published series [2Simmin A. Beaulé P.E. Campbell P.A. Current concepts review: metal on metal hip resurfacing.J Bone Joint Surg. 2008; 90: 637Crossref PubMed Scopus (195) Google Scholar, 3Campbell P. Shen F.W. McKellop H. Biologic and tribologic considerations of alternative bearing surfaces.Clin Orthop. 2004; : 98Crossref PubMed Scopus (94) Google Scholar]. One article is about resurfacing rather than conventional total hip arthroplasty. Resurfacing was not specifically addressed in our editorial, but we welcome the chance to widen the discussion. We recognize that there are some articles showing good survivorship of resurfacing. However, in the overall operating surgeons' hands, the results of resurfacing are not as good as conventional total hip arthroplasty. As previously stated, this is highlighted by the Australian and UK registries [4AOA Australian Orthopaedic Association National Joint Replacement Registry annual report. AOA, Adelaide2008Google Scholar, 5The National Joint Registry 5th annual report. Hemel Hempstead: National Joint Registry for England and Wales; 2009.Google Scholar] that state that hip resurfacing shows the highest revision rates in early and at midterm results. Two articles by Dr Beaulé, a coauthor on the letter to the editor to which we reply, serve to reinforce this point. The first article looks at causes of early failure in a multicenter clinical trial of hip resurfacing [6Kim P.R. Beaulé P.E. Laflamme F.Y. et al.Causes of early failure in a multicentre clinical trial of hip resurfacing.J Arthroplasty. 2008; 23Google Scholar]. Dr Beaulé and his coauthors report a 7% revision rate for resurfacing in 200 patients by 2 years. The patients who failed were younger and heavier. This high failure rate was put down to a learning curve. A learning curve to a surgeon is a failure to a patient. An operation that has a long learning curve and is difficult needs to be placed in context. If every operating surgeon goes through a long learning curve, many patients will have adverse outcomes. It would appear from the published literature and from the article by Dr Beaulé that resurfacing is a difficult operation that should not be done in the general orthopedic community. We also refer to a second article by Dr Beaulé et al looking at the Canadian Academic experience with metal-on-metal hip resurfacing. In this study, a 3.2% failure rate at 2 years and 1.6% femoral neck fracture rate was reported. Again, this is a high failure rate so early in the implantation of the prosthesis. The contributing surgeons are all experts in arthroplasty and are performing high volumes of hip arthroplasty. Such a high failure rate in the very best hands is concerning. Furthermore, the authors state that their results are better than in previous multicenter trials. This article highlights that hip resurfacing has very high failure rates when performed in the general orthopedic surgeon's hands. Even in the very best hands it has a high failure rate! Next, we would like to review another article by Dr Beaulé in 2010 looking at the incidence of groin pain after metal-on-metal hip resurfacing [7O'Neill M. Beaulé P.E. Bin Nasser A. et al.Canadian academic experience with metal-on-metal hip resurfacing.Bull NYU Hosp Jt Dis. 2009; : 67Google Scholar]. In this article, Dr Beaulé reviewed hip resurfacing in young patients in a single institution. He reported that 18% of the patients had significant groin pain, of which 10% of the total number of patients said that the pain limited their activities of daily living. Also, 10% of patients required ongoing medication for pain. One should question if it is reasonable to perform an operation that has an 18% incidence of ongoing pain requiring either analgesia or modification to activities in a young active population. The authors conclude that their rate of groin pain is between 4 and 50 times higher than previously reported groin pain in patients undergoing total hip arthroplasties. This article highlights yet another unexpected clinical problem associated with metal on metal bearings. It is not clear whether metal-on-metal or resurfacing is the cause of this incidence but the clinical conclusion is in no doubt. Under subheading no. 2, Dr Vendittoli et al discuss the issue of a learning curve, modified surgical technique and ‘unproven' metal on metal devices. They highlight a large number of metal-on-metal implants that they considered as unacceptable. It is reasonable that we continue to innovate in total hip arthroplasty but at what cost? Metal-on-metal bearings either in a total hip or a resurfacing do not show any clinical advantage [8Bin Nasser A. Beaulé P.E. O'Neill M. et al.Incidence of groin pain after metal-on-metal resurfacing.Clin Orthop Relat Res. 2010; 468: 392Crossref PubMed Scopus (54) Google Scholar]. Instead they are producing a new series of complications such as those highlighted above with reference to groin pain. We see no reason to change our position that metal on metal bearings should be ‘used with great caution if at all'.