Journal of Orthopaedic Surgery 2015;23(1):107-10
Review article: Outcome of total knee arthroplasty in obese patients E Carlos Rodriguez-Merchan
La Paz University Hospital, Madrid, Spain
ABSTRACT The MEDLINE database was searched using the key words: ‘obesity’ and ‘knee arthroplasty’. 41 articles focused on the topic were reviewed; most studies were prospective case series (providing low-level evidence) and 3 were systematic reviews. 16 studies reported no adverse association between obesity and total knee arthroplasty (TKA) outcome, whereas 24 studies reported a poorer TKA outcome in obese patients. In the 3 systematic reviews, obesity was reported to adversely affect the outcome, the rate of complications, implant survival, and the cost of TKA. Key words: arthroplasty, replacement, knee; obesity
INTRODUCTION Obesity is defined as being 20% or more over the ideal body weight; a body mass index (BMI) of 25.9 to 29 kg/m2 is defined as overweight, and
≥30 kg/m2 as obese.1 Excessive weight increases the risk of hypertension, type-2 diabetes mellitus, coronary disease, unexplained myocardial infarction, hyperlipidaemia, infertility, and colon, prostate, and endometrial cancer. Obese patients with advanced knee osteoarthritis are poor candidates for total knee arthroplasty (TKA),2 and are often advised against TKA.3,4 REVIEW The MEDLINE database was searched using the key words: ‘obesity’ and ‘knee arthroplasty’. 41 articles focused on the topic were reviewed; most studies were prospective case series (providing low-level evidence) and 3 were systematic reviews. 16 studies reported no adverse association between obesity and TKA outcome.2–17 Obesity/ BMI/body weight was not adversely associated with post-TKA functional outcome at 1, 3, 6, and 12 months,4,7,12 pain outcome at 2 and 5 years,8 Hospital for Special Surgery score,2 or Knee Society Score, Western Ontario and McMaster Universities Arthritis
Address correspondence and reprint requests to: E Carlos Rodriguez-Merchan, La Paz University Hospital, Madrid, Spain. Email: [email protected]
Journal of Orthopaedic Surgery
108 EC Rodriguez-Merchan
Index, and Short Form-12 Health Survey score at 9.5 years.5 Obese and morbidly obese patients were reported to gain as much functional benefit (and relief of symptoms16) from TKA as other patients at 3 years.17 Obese patients should not be excluded from the benefit of TKA, as their overall improvement was equivalent to lower-BMI patients.6,15 Perioperative complication rates were similarly low in both obese and non-obese patients undergoing TKA,9,11,13,16 as were mid- and long-term survival rates,3,5,13,14 despite a weak correlation between BMI and early complications.11 Mid-term survival rates were shown to be similar in normal weight and mildly and moderately obese patients.3,13,14 Kaplan Meier survivorship (with any reoperation as an end point) was 98% in both obese and non-obese patients.5 24 studies reported a poorer TKA outcome in obese patients.18–41 Obese patients were reported to have lower post-TKA scores.19 Weight and BMI was noted to have negative effects on post-TKA function and quality of life and satisfaction level.21,28 Obesity adversely affected clinical results in diabetic patients.22 Improvement in Knee Society Scores after TKA was reported to be significantly lower in morbidly obese (>40 BMI) patients than in controls.32 At 5 years post-TKA, Knee Society Scores were significantly lower in morbidly obese patients than in non-obese patients, but not significantly different between obese and non-obese patients.29 Obese patients had a significantly lower post-TKA activity score and higher complication rates (10.5 vs. 3.8%).30 An increase in BMI increased the risk of poor clinical outcome and quality of life 3 to 5 years after TKA.31 Severe obesity was an independent risk factor for slow recovery after TKA over 3 years.34 Obese patients had higher rates of diabetes and hypertension; the risk of infection was 6.7 times higher in obese than non-obese patients.18 Morbid obesity or obesity combined with diabetes was a risk factor for infection.23 The rate of complications in morbidly obese (>40 BMI) patients was 10% to 30%; in particular, the rate of deep prosthetic infection was 3 to 9 times that of controls.32 Infection and deep infection
occurred more often in obese patients, with the respective odds ratio of 1.90 and 2.38.35 Obese patients should be advised of the higher rates of prosthetic joint infection prior to TKA.36,39 Morbid obesity was associated with increased early complications such as peripheral oedema, diarrhoea, and gastrointestinal or abdominal pain, wound inflammation or infection, extrasurgical-site infections, and respiratory tract or lung infections (but was not associated with an increased risk of venous thromboembolism or bleeding).38 Obese patients should be advised to lose weight and the benefit of bariatric surgery before TKA.32 Both preoperative mechanical limb alignment and BMI have a significant effect on post-TKA limb alignment.40 Obesity was a risk factor for post-TKA deep vein thrombosis.19 Weight and BMI have negative effects on the longevity of primary TKA.21 Morbidly obese patients have a significantly lower implant survivorship than obese or non-obese patients at 5 years.29 Revision of the TKA (exchange or removal of the components for any reason) occurs more often in obese patients, with an odds ratio of 1.30.35 Obesity is an independent risk factor for revision TKA within 12 months.37 Hospital resource consumption for unilateral primary TKA is 7% higher in morbidly obese patients than non-obese patients.25 Obesity is associated with higher inpatient index surgery costs and episode of care costs.27 CONCLUSION 16 studies reported no adverse association between obesity and TKA outcome,2–17 whereas 24 studies reported a poorer TKA outcome in obese patients.18–41 In the 3 systematic reviews,29,32,35 obesity was shown to adversely affect the outcome, the rate of complications, implant survival, and the cost of TKA. DISCLOSURE No conflicts of interest were declared by the authors.
REFERENCES 1. The Free Dictionary. Obesity. http://medical-dictionary.thefreedictionary.com/Obesity 2. Marcacci M, Iacono F, Zaffagnini S, Visani A, Loreti I, Petitto A, et al. Total knee arthroplasty without patellar resurfacing in active and overweight patients. Knee Surg Sports Traumatol Arthrosc 1997;5:258–61. 3. Hamoui N, Kantor S, Vince K, Crookes PF. Long-term outcome of total knee replacement: does obesity matter? Obes Surg 2006;16:35–8. 4. Deshmukh RG, Hayes JH, Pinder IM. Does body weight influence outcome after total knee arthroplasty? A 1-year analysis.
Vol. 23 No. 1, April 2015
Outcome of total knee arthroplasty in obese patients 109
J Arthroplasty 2002;17:315–9. 5. Bourne RB, McCalden RW, MacDonald SJ, Mokete L, Guerin J. Influence of patient factors on TKA outcomes at 5 to 11 years follow up. Clin Orthop Relat Res 2007;464:27–31. 6. Ersozlu S, Akkaya T, Ozgur AF, Sahin O, Senturk I, Tandogan R. Bilateral staged total knee arthroplasty in obese patients. Arch Orthop Trauma Surg 2008;128:143–8. 7. Stevens-Lapsley JE, Petterson SC, Mizner RL, Snyder-Mackler L. Impact of body mass index on functional performance after total knee arthroplasty. J Arthroplasty 2010;25:1104–9. 8. Singh JA, Gabriel SE, Lewallen DG. Higher body mass index is not associated with worse pain outcomes after primary or revision total knee arthroplasty. J Arthroplasty 2011;26:366–74. 9. Suleiman LI, Ortega G, Ong’uti SK, Gonzalez DO, Tran DD, Onyike A, et al. Does BMI affect perioperative complications following total knee and hip arthroplasty? J Surg Res 2012;174:7–11. 10. Bin Abd Razak HR, Chong HC, Tan AH. Obesity does not imply poor outcomes in Asians after total knee arthroplasty. Clin Orthop Relat Res 2013;471:1957–63. 11. Patel AD, Albrizio M. Relationship of body mass index to early complications in knee replacement surgery. Arch Orthop Trauma Surg 2008;128:5–9. 12. Rajgopal V, Bourne RB, Chesworth BM, MacDonald SJ, McCalden RW, Rorabeck CH. The impact of morbid obesity on patient outcomes after total knee arthroplasty. J Arthroplasty 2008;23:795–800. 13. Bordini B, Stea S, Cremonini S, Viceconti M, De Palma R, Toni A. Relationship between obesity and early failure of total knee prostheses. BMC Musculoskelet Disord 2009;10:29. 14. Yeung E, Jackson M, Sexton S, Walter W, Zicat B, Walter W. The effect of obesity on the outcome of hip and knee arthroplasty. Int Orthop 2011;35:929–34. 15. Baker P, Petheram T, Jameson S, Reed M, Gregg P, Deehan D. The association between body mass index and the outcomes of total knee arthroplasty. J Bone Joint Surg Am 2012;94:1501–8. 16. Collins RA, Walmsley PJ, Amin AK, Brenkel IJ, Clayton RA. Does obesity influence clinical outcome at nine years following total knee replacement? J Bone Joint Surg Br 2012;94:1351–5. 17. Baker P, Muthumayandi K, Gerrand C, Kleim B, Bettinson K, Deehan D. Influence of body mass index (BMI) on functional improvements at 3 years following total knee replacement: a retrospective cohort study. PLoS One 2013;8:e59079. 18. Namba RS, Paxton L, Fithian DC, Stone ML. Obesity and perioperative morbidity in total hip and total knee arthroplasty patients. J Arthroplasty 2005;20(7 Suppl 3):46–50. 19. Guan Z, Chen Y, Song Y. Influence of body mass index and age on deep vein thrombosis after total hip and knee arthroplasty [in Chinese]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2006;20:611–5. 20. Gillespie GN, Porteous AJ. Obesity and knee arthroplasty. Knee 2007;14:81–6. 21. Mulhall KJ, Ghomrawi HM, Mihalko W, Cui Q, Saleh KJ. Adverse effects of increased body mass index and weight on survivorship of total knee arthroplasty and subsequent outcomes of revision TKA. J Knee Surg 2007;20:199–204. 22. Moon HK, Han CD, Yang IH, Cha BS. Factors affecting outcome after total knee arthroplasty in patients with diabetes mellitus. Yonsei Med J 2008;49:129–37. 23. Dowsey MM, Choong PF. Obese diabetic patients are at substantial risk for deep infection after primary TKA. Clin Orthop Relat Res 2009;467:1577–81. 24. Yasunaga H, Tsuchiya K, Matsuyama Y, Ohe K. Analysis of factors affecting operating time, postoperative complications, and length of stay for total knee arthroplasty: nationwide web-based survey. J Orthop Sci 2009;14:10–6. 25. Kim SH. Morbid obesity and excessive hospital resource consumption for unilateral primary hip and knee arthroplasty. J Arthroplasty 2010;25:1258–66. 26. Järvenpää J, Kettunen J, Kröger H, Miettinen H. Obesity may impair the early outcome of total knee arthroplasty. Scand J Surg 2010;99:45–9. 27. Dowsey MM, Liew D, Choong PF. Economic burden of obesity in primary total knee arthroplasty. Arthritis Care Res (Hoboken) 2011;63:1375–81. 28. Järvenpää J, Kettunen J, Soininvaara T, Miettinen H, Kröger H. Obesity has a negative impact on clinical outcome after total knee arthroplasty. Scand J Surg 2012;101:198–203. 29. McElroy MJ, Pivec R, Issa K, Harwin SF, Mont MA. The effects of obesity and morbid obesity on outcomes in TKA. J Knee Surg 2013;26:83–8. 30. Issa K, Pivec R, Kapadia BH, Shah T, Harwin SF, Delanois RE, et al. Does obesity affect the outcomes of primary total knee arthroplasty? J Knee Surg 2013;26:89–94. 31. Liljensøe A, Lauersen JO, Søballe K, Mechlenburg I. Overweight preoperatively impairs clinical outcome after knee arthroplasty: a cohort study of 197 patients 3–5 years after surgery. Acta Orthop 2013;84:392–7. 32. Samson AJ, Mercer GE, Campbell DG. Total knee replacement in the morbidly obese: a literature review. ANZ J Surg 2010;80:595–9. 33. Schwarzkopf R, Thompson SL, Adwar SJ, Liublinska V, Slover JD. Postoperative complication rates in the “super-obese” hip and knee arthroplasty population. J Arthroplasty 2012;27:397–401. 34. Jones CA, Cox V, Jhangri GS, Suarez-Almazor ME. Delineating the impact of obesity and its relationship on recovery after total joint arthroplasties. Osteoarthritis Cartilage 2012;20:511–8. 35. Kerkhoffs GM, Servien E, Dunn W, Dahm D, Bramer JA, Haverkamp D. The influence of obesity on the complication rate and outcome of total knee arthroplasty: a meta-analysis and systematic literature review. J Bone Joint Surg Am 2012;94:1839– 44. 36. Liabaud B, Patrick DA Jr, Geller JA. Higher body mass index leads to longer operative time in total knee arthroplasty. J
110 EC Rodriguez-Merchan
Journal of Orthopaedic Surgery
Arthroplasty 2013;28:563–5. 37. Bozic KJ, Lau E, Ong K, Chan V, Kurtz S, Vail TP, et al. Risk factors for early revision after primary total hip arthroplasty in Medicare patients. Clin Orthop Relat Res 2014;472:449–54. 38. Friedman RJ, Hess S, Berkowitz SD, Homering M. Complication rates after hip or knee arthroplasty in morbidly obese patients. Clin Orthop Relat Res 2013;471:3358–66. 39. Pruzansky JS, Bronson MJ, Grelsamer RP, Strauss E, Moucha CS. Prevalence of modifiable surgical site infection risk factors in hip and knee joint arthroplasty patients at an urban academic hospital. J Arthroplasty 2014;29:272–6. 40. Estes CS, Schmidt KJ, McLemore R, Spangehl MJ, Clarke HD. Effect of body mass index on limb alignment after total knee arthroplasty. J Arthroplasty 2013;28(8 Suppl):101–5. 41. Odum SM, Springer BD, Dennos AC, Fehring TK. National obesity trends in total knee arthroplasty. J Arthroplasty 2013;28(8 Suppl):148–51.
Review article: Outcome of total knee arthroplasty in obese patients E Carlos Rodriguez-Merchan
La Paz University Hospital, Madrid, Spain
ABSTRACT The MEDLINE database was searched using the key words: ‘obesity’ and ‘knee arthroplasty’. 41 articles focused on the topic were reviewed; most studies were prospective case series (providing low-level evidence) and 3 were systematic reviews. 16 studies reported no adverse association between obesity and total knee arthroplasty (TKA) outcome, whereas 24 studies reported a poorer TKA outcome in obese patients. In the 3 systematic reviews, obesity was reported to adversely affect the outcome, the rate of complications, implant survival, and the cost of TKA. Key words: arthroplasty, replacement, knee; obesity
INTRODUCTION Obesity is defined as being 20% or more over the ideal body weight; a body mass index (BMI) of 25.9 to 29 kg/m2 is defined as overweight, and
≥30 kg/m2 as obese.1 Excessive weight increases the risk of hypertension, type-2 diabetes mellitus, coronary disease, unexplained myocardial infarction, hyperlipidaemia, infertility, and colon, prostate, and endometrial cancer. Obese patients with advanced knee osteoarthritis are poor candidates for total knee arthroplasty (TKA),2 and are often advised against TKA.3,4 REVIEW The MEDLINE database was searched using the key words: ‘obesity’ and ‘knee arthroplasty’. 41 articles focused on the topic were reviewed; most studies were prospective case series (providing low-level evidence) and 3 were systematic reviews. 16 studies reported no adverse association between obesity and TKA outcome.2–17 Obesity/ BMI/body weight was not adversely associated with post-TKA functional outcome at 1, 3, 6, and 12 months,4,7,12 pain outcome at 2 and 5 years,8 Hospital for Special Surgery score,2 or Knee Society Score, Western Ontario and McMaster Universities Arthritis
Address correspondence and reprint requests to: E Carlos Rodriguez-Merchan, La Paz University Hospital, Madrid, Spain. Email: [email protected]
Journal of Orthopaedic Surgery
108 EC Rodriguez-Merchan
Index, and Short Form-12 Health Survey score at 9.5 years.5 Obese and morbidly obese patients were reported to gain as much functional benefit (and relief of symptoms16) from TKA as other patients at 3 years.17 Obese patients should not be excluded from the benefit of TKA, as their overall improvement was equivalent to lower-BMI patients.6,15 Perioperative complication rates were similarly low in both obese and non-obese patients undergoing TKA,9,11,13,16 as were mid- and long-term survival rates,3,5,13,14 despite a weak correlation between BMI and early complications.11 Mid-term survival rates were shown to be similar in normal weight and mildly and moderately obese patients.3,13,14 Kaplan Meier survivorship (with any reoperation as an end point) was 98% in both obese and non-obese patients.5 24 studies reported a poorer TKA outcome in obese patients.18–41 Obese patients were reported to have lower post-TKA scores.19 Weight and BMI was noted to have negative effects on post-TKA function and quality of life and satisfaction level.21,28 Obesity adversely affected clinical results in diabetic patients.22 Improvement in Knee Society Scores after TKA was reported to be significantly lower in morbidly obese (>40 BMI) patients than in controls.32 At 5 years post-TKA, Knee Society Scores were significantly lower in morbidly obese patients than in non-obese patients, but not significantly different between obese and non-obese patients.29 Obese patients had a significantly lower post-TKA activity score and higher complication rates (10.5 vs. 3.8%).30 An increase in BMI increased the risk of poor clinical outcome and quality of life 3 to 5 years after TKA.31 Severe obesity was an independent risk factor for slow recovery after TKA over 3 years.34 Obese patients had higher rates of diabetes and hypertension; the risk of infection was 6.7 times higher in obese than non-obese patients.18 Morbid obesity or obesity combined with diabetes was a risk factor for infection.23 The rate of complications in morbidly obese (>40 BMI) patients was 10% to 30%; in particular, the rate of deep prosthetic infection was 3 to 9 times that of controls.32 Infection and deep infection
occurred more often in obese patients, with the respective odds ratio of 1.90 and 2.38.35 Obese patients should be advised of the higher rates of prosthetic joint infection prior to TKA.36,39 Morbid obesity was associated with increased early complications such as peripheral oedema, diarrhoea, and gastrointestinal or abdominal pain, wound inflammation or infection, extrasurgical-site infections, and respiratory tract or lung infections (but was not associated with an increased risk of venous thromboembolism or bleeding).38 Obese patients should be advised to lose weight and the benefit of bariatric surgery before TKA.32 Both preoperative mechanical limb alignment and BMI have a significant effect on post-TKA limb alignment.40 Obesity was a risk factor for post-TKA deep vein thrombosis.19 Weight and BMI have negative effects on the longevity of primary TKA.21 Morbidly obese patients have a significantly lower implant survivorship than obese or non-obese patients at 5 years.29 Revision of the TKA (exchange or removal of the components for any reason) occurs more often in obese patients, with an odds ratio of 1.30.35 Obesity is an independent risk factor for revision TKA within 12 months.37 Hospital resource consumption for unilateral primary TKA is 7% higher in morbidly obese patients than non-obese patients.25 Obesity is associated with higher inpatient index surgery costs and episode of care costs.27 CONCLUSION 16 studies reported no adverse association between obesity and TKA outcome,2–17 whereas 24 studies reported a poorer TKA outcome in obese patients.18–41 In the 3 systematic reviews,29,32,35 obesity was shown to adversely affect the outcome, the rate of complications, implant survival, and the cost of TKA. DISCLOSURE No conflicts of interest were declared by the authors.
REFERENCES 1. The Free Dictionary. Obesity. http://medical-dictionary.thefreedictionary.com/Obesity 2. Marcacci M, Iacono F, Zaffagnini S, Visani A, Loreti I, Petitto A, et al. Total knee arthroplasty without patellar resurfacing in active and overweight patients. Knee Surg Sports Traumatol Arthrosc 1997;5:258–61. 3. Hamoui N, Kantor S, Vince K, Crookes PF. Long-term outcome of total knee replacement: does obesity matter? Obes Surg 2006;16:35–8. 4. Deshmukh RG, Hayes JH, Pinder IM. Does body weight influence outcome after total knee arthroplasty? A 1-year analysis.
Vol. 23 No. 1, April 2015
Outcome of total knee arthroplasty in obese patients 109
J Arthroplasty 2002;17:315–9. 5. Bourne RB, McCalden RW, MacDonald SJ, Mokete L, Guerin J. Influence of patient factors on TKA outcomes at 5 to 11 years follow up. Clin Orthop Relat Res 2007;464:27–31. 6. Ersozlu S, Akkaya T, Ozgur AF, Sahin O, Senturk I, Tandogan R. Bilateral staged total knee arthroplasty in obese patients. Arch Orthop Trauma Surg 2008;128:143–8. 7. Stevens-Lapsley JE, Petterson SC, Mizner RL, Snyder-Mackler L. Impact of body mass index on functional performance after total knee arthroplasty. J Arthroplasty 2010;25:1104–9. 8. Singh JA, Gabriel SE, Lewallen DG. Higher body mass index is not associated with worse pain outcomes after primary or revision total knee arthroplasty. J Arthroplasty 2011;26:366–74. 9. Suleiman LI, Ortega G, Ong’uti SK, Gonzalez DO, Tran DD, Onyike A, et al. Does BMI affect perioperative complications following total knee and hip arthroplasty? J Surg Res 2012;174:7–11. 10. Bin Abd Razak HR, Chong HC, Tan AH. Obesity does not imply poor outcomes in Asians after total knee arthroplasty. Clin Orthop Relat Res 2013;471:1957–63. 11. Patel AD, Albrizio M. Relationship of body mass index to early complications in knee replacement surgery. Arch Orthop Trauma Surg 2008;128:5–9. 12. Rajgopal V, Bourne RB, Chesworth BM, MacDonald SJ, McCalden RW, Rorabeck CH. The impact of morbid obesity on patient outcomes after total knee arthroplasty. J Arthroplasty 2008;23:795–800. 13. Bordini B, Stea S, Cremonini S, Viceconti M, De Palma R, Toni A. Relationship between obesity and early failure of total knee prostheses. BMC Musculoskelet Disord 2009;10:29. 14. Yeung E, Jackson M, Sexton S, Walter W, Zicat B, Walter W. The effect of obesity on the outcome of hip and knee arthroplasty. Int Orthop 2011;35:929–34. 15. Baker P, Petheram T, Jameson S, Reed M, Gregg P, Deehan D. The association between body mass index and the outcomes of total knee arthroplasty. J Bone Joint Surg Am 2012;94:1501–8. 16. Collins RA, Walmsley PJ, Amin AK, Brenkel IJ, Clayton RA. Does obesity influence clinical outcome at nine years following total knee replacement? J Bone Joint Surg Br 2012;94:1351–5. 17. Baker P, Muthumayandi K, Gerrand C, Kleim B, Bettinson K, Deehan D. Influence of body mass index (BMI) on functional improvements at 3 years following total knee replacement: a retrospective cohort study. PLoS One 2013;8:e59079. 18. Namba RS, Paxton L, Fithian DC, Stone ML. Obesity and perioperative morbidity in total hip and total knee arthroplasty patients. J Arthroplasty 2005;20(7 Suppl 3):46–50. 19. Guan Z, Chen Y, Song Y. Influence of body mass index and age on deep vein thrombosis after total hip and knee arthroplasty [in Chinese]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2006;20:611–5. 20. Gillespie GN, Porteous AJ. Obesity and knee arthroplasty. Knee 2007;14:81–6. 21. Mulhall KJ, Ghomrawi HM, Mihalko W, Cui Q, Saleh KJ. Adverse effects of increased body mass index and weight on survivorship of total knee arthroplasty and subsequent outcomes of revision TKA. J Knee Surg 2007;20:199–204. 22. Moon HK, Han CD, Yang IH, Cha BS. Factors affecting outcome after total knee arthroplasty in patients with diabetes mellitus. Yonsei Med J 2008;49:129–37. 23. Dowsey MM, Choong PF. Obese diabetic patients are at substantial risk for deep infection after primary TKA. Clin Orthop Relat Res 2009;467:1577–81. 24. Yasunaga H, Tsuchiya K, Matsuyama Y, Ohe K. Analysis of factors affecting operating time, postoperative complications, and length of stay for total knee arthroplasty: nationwide web-based survey. J Orthop Sci 2009;14:10–6. 25. Kim SH. Morbid obesity and excessive hospital resource consumption for unilateral primary hip and knee arthroplasty. J Arthroplasty 2010;25:1258–66. 26. Järvenpää J, Kettunen J, Kröger H, Miettinen H. Obesity may impair the early outcome of total knee arthroplasty. Scand J Surg 2010;99:45–9. 27. Dowsey MM, Liew D, Choong PF. Economic burden of obesity in primary total knee arthroplasty. Arthritis Care Res (Hoboken) 2011;63:1375–81. 28. Järvenpää J, Kettunen J, Soininvaara T, Miettinen H, Kröger H. Obesity has a negative impact on clinical outcome after total knee arthroplasty. Scand J Surg 2012;101:198–203. 29. McElroy MJ, Pivec R, Issa K, Harwin SF, Mont MA. The effects of obesity and morbid obesity on outcomes in TKA. J Knee Surg 2013;26:83–8. 30. Issa K, Pivec R, Kapadia BH, Shah T, Harwin SF, Delanois RE, et al. Does obesity affect the outcomes of primary total knee arthroplasty? J Knee Surg 2013;26:89–94. 31. Liljensøe A, Lauersen JO, Søballe K, Mechlenburg I. Overweight preoperatively impairs clinical outcome after knee arthroplasty: a cohort study of 197 patients 3–5 years after surgery. Acta Orthop 2013;84:392–7. 32. Samson AJ, Mercer GE, Campbell DG. Total knee replacement in the morbidly obese: a literature review. ANZ J Surg 2010;80:595–9. 33. Schwarzkopf R, Thompson SL, Adwar SJ, Liublinska V, Slover JD. Postoperative complication rates in the “super-obese” hip and knee arthroplasty population. J Arthroplasty 2012;27:397–401. 34. Jones CA, Cox V, Jhangri GS, Suarez-Almazor ME. Delineating the impact of obesity and its relationship on recovery after total joint arthroplasties. Osteoarthritis Cartilage 2012;20:511–8. 35. Kerkhoffs GM, Servien E, Dunn W, Dahm D, Bramer JA, Haverkamp D. The influence of obesity on the complication rate and outcome of total knee arthroplasty: a meta-analysis and systematic literature review. J Bone Joint Surg Am 2012;94:1839– 44. 36. Liabaud B, Patrick DA Jr, Geller JA. Higher body mass index leads to longer operative time in total knee arthroplasty. J
110 EC Rodriguez-Merchan
Journal of Orthopaedic Surgery
Arthroplasty 2013;28:563–5. 37. Bozic KJ, Lau E, Ong K, Chan V, Kurtz S, Vail TP, et al. Risk factors for early revision after primary total hip arthroplasty in Medicare patients. Clin Orthop Relat Res 2014;472:449–54. 38. Friedman RJ, Hess S, Berkowitz SD, Homering M. Complication rates after hip or knee arthroplasty in morbidly obese patients. Clin Orthop Relat Res 2013;471:3358–66. 39. Pruzansky JS, Bronson MJ, Grelsamer RP, Strauss E, Moucha CS. Prevalence of modifiable surgical site infection risk factors in hip and knee joint arthroplasty patients at an urban academic hospital. J Arthroplasty 2014;29:272–6. 40. Estes CS, Schmidt KJ, McLemore R, Spangehl MJ, Clarke HD. Effect of body mass index on limb alignment after total knee arthroplasty. J Arthroplasty 2013;28(8 Suppl):101–5. 41. Odum SM, Springer BD, Dennos AC, Fehring TK. National obesity trends in total knee arthroplasty. J Arthroplasty 2013;28(8 Suppl):148–51.
