Must Bilaterality Be Considered In Statistical Analyses of Total Knee Arthroplasty?
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In studies of TKA, treating each knee as an independent case in patients with bilateral TKAs can lead to errors, because patients with bilateral and unilateral TKAs may achieve different levels of function and because the assumption of statistical independence is violated.
We determined whether (1) patients undergoing bilateral TKAs have different demographics and preoperative and postoperative function from those undergoing unilateral TKAs, and (2) means, SEs, and p values change substantially based on how the two cases of bilateral TKAs are treated in statistical analyses.
We retrospectively compared 513 patients undergoing unilateral TKAs and 602 patients undergoing bilateral TKAs regarding demographics (age, gender, BMI), preoperative and 1-year postoperative function (motion arc, American Knee Society score, patellofemoral score, WOMACTM, SF-36). Each case of a bilateral TKA was treated as independent in the reference analyses. Then changes of mean, SEs, and p values were compared with those of the reference method when three other methods of analysis were used: using mean values of both knees, randomly selecting one side, and using a generalized estimating equation.
Patients undergoing bilateral TKAs had higher female predominance (95% versus 90%) and BMI (27.4 versus 26.1 kg/m2) than those undergoing unilateral TKAs. Although patients undergoing bilateral TKAs had worse preoperative function, they achieved comparable function at 1 year. The mean values did not differ considerably depending on the four methods. The SEs and p values of the reference method were generally the smallest, but the differences appeared negligible.
Our analyses suggest bilaterality can be ignored in the analysis of TKA, since postoperative function is comparable between unilateral and bilateral TKAs and the theoretical errors in statistical analysis had little effect on the results.
- Aglietti, P, Buzzi, R, Felice, R, Giron, F (1999) The Insall-Burstein total knee replacement in osteoarthritis: a 10-year-minimum follow-up. J Arthroplasty. 14: pp. 560-565 CrossRef
- Angst, F, Aeschlimann, A, Stucki, G (2001) Smallest detectable and minimal clinically important differences of rehabilitation intervention with their implications for required sample sizes using WOMAC and SF-36 quality of life measurement instruments in patients with osteoarthritis of the lower extremities. Arthritis Rheum. 45: pp. 384-391 CrossRef
- Bellamy, N, Buchanan, WW, Goldsmith, CH, Campbell, J, Stitt, LW (1988) Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. J Rheumatol. 15: pp. 1833-1840
- Bjorgul, K, Novicoff, WM, Brevig, K, Ahlund, O, Wiig, M, Saleh, KJ (2011) Patients with bilateral procedures can be included in total hip arthroplasty research without biasing results. J Arthroplasty. 26: pp. 120-123 CrossRef
- Brown H, Prescott R. Applied Mixed Models in Medicine. Chichester, England; Hoboken, NJ: John Wiley; 2006.
- Bryant, D, Havey, TC, Roberts, R, Guyatt, G (2006) How many patients? How many limbs? Analysis of patients or limbs in the orthopaedic literature: a systematic review. J Bone Joint Surg Am. 88: pp. 41-45 CrossRef
- Buechel, FF (2002) Long-term followup after mobile-bearing total knee replacement. Clin Orthop Relat Res. 404: pp. 40-50 CrossRef
- Bullock, DP, Sporer, SM, Shirreffs, TG (2003) Comparison of simultaneous bilateral with unilateral total knee arthroplasty in terms of perioperative complications. J Bone Joint Surg Am. 85: pp. 1981-1986
- Callahan, CM, Drake, BG, Heck, DA, Dittus, RS (1994) Patient outcomes following tricompartmental total knee replacement: a meta-analysis. JAMA. 271: pp. 1349-1357 CrossRef
- Cohen, RG, Forrest, CJ, Benjamin, JB (1997) Safety and efficacy of bilateral total knee arthroplasty. J Arthroplasty. 12: pp. 497-502 CrossRef
- Cross, WW, Saleh, KJ, Wilt, TJ, Kane, RL (2006) Agreement about indications for total knee arthroplasty. Clin Orthop Relat Res. 446: pp. 34-39 CrossRef
- Farquhar, S, Snyder-Mackler, L (2010) The Chitranjan Ranawat Award: The nonoperated knee predicts function 3 years after unilateral total knee arthroplasty. Clin Orthop Relat Res. 468: pp. 37-44 CrossRef
- Feller, JA, Bartlett, RJ, Lang, DM (1996) Patellar resurfacing versus retention in total knee arthroplasty. J Bone Joint Surg Br. 78: pp. 226-228
- Felson, DT, Anderson, JJ, Naimark, A, Walker, AM, Meenan, RF (1988) Obesity and knee osteoarthritis: the Framingham Study. Ann Intern Med. 109: pp. 18-24 CrossRef
- Fick, D, Crane, T, Shakespeare, D (2002) A comparison of bilateral vs. unilateral total knee arthroplasty mobilised using a flexion regime. Knee. 9: pp. 285-289 CrossRef
- Gelber, AC, Hochberg, MC, Mead, LA, Wang, NY, Wigley, FM, Klag, MJ (1999) Body mass index in young men and the risk of subsequent knee and hip osteoarthritis. Am J Med. 107: pp. 542-548 CrossRef
- Havelin, LI, Espehaug, B, Vollset, SE, Engesaeter, LB (1995) The effect of the type of cement on early revision of Charnley total hip prostheses: a review of eight thousand five hundred and seventy-nine primary arthroplasties from the Norwegian Arthroplasty Register. J Bone Joint Surg Am. 77: pp. 1543-1550
- Hickey, BA, Kempshall, PJ, Metcalfe, AJ, Forster, MC (2012) Review of Kinemax total knee replacements performed at the NHS treatment centre, Weston-Super-Mare: five-year results. J Bone Joint Surg Br. 94: pp. 510-516 CrossRef
- Hooper, GJ, Hooper, NM, Rothwell, AG, Hobbs, T (2009) Bilateral total joint arthroplasty: the early results from the New Zealand National Joint Registry. J Arthroplasty. 24: pp. 1174-1177 CrossRef
- Insall, JN, Dorr, LD, Scott, RD, Scott, WN (1989) Rationale of the Knee Society clinical rating system. Clin Orthop Relat Res. 248: pp. 13-14
- Kalisvaart, MM, Pagnano, MW, Trousdale, RT, Stuart, MJ, Hanssen, AD (2012) Randomized clinical trial of rotating-platform and fixed-bearing total knee arthroplasty: no clinically detectable differences at five years. J Bone Joint Surg Am. 94: pp. 481-489 CrossRef
- Kellgren, JH, Lawrence, JS (1957) Radiological assessment of osteo-arthrosis. Ann Rheum Dis. 16: pp. 494-502 CrossRef
- Kelly, MA, Clarke, HD (2002) Long-Term Results of Posterior Cruciate-Substituting Total Knee Arthroplasty. Clin Orthop Relat Res. 404: pp. 51-57 CrossRef
- Kim, JM, Moon, MS (1995) Squatting following total knee arthroplasty. Clin Orthop Relat Res. 313: pp. 177-186
- Kim, TK, Chang, CB, Kang, YG, Kim, SJ, Seong, SC (2009) Causes and predictors of patient’s dissatisfaction after uncomplicated total knee arthroplasty. J Arthroplasty. 24: pp. 263-271 CrossRef
- Kim, YH, Choi, YW, Kim, JS (2009) Simultaneous bilateral sequential total knee replacement is as safe as unilateral total knee replacement. J Bone Joint Surg Br. 91: pp. 64-68
- Kim, YH, Sohn, KS, Kim, JS (2005) Range of motion of standard and high-flexion posterior stabilized total knee prostheses: a prospective, randomized study. J Bone Joint Surg Am. 87: pp. 1470-1475 CrossRef
- Koh IJ, Kim TK, Chang CB, Cho HJ, In Y. Trends in use of total knee arthroplasty in Korea from 2001 to 2010. Clin Orthop Relat Res. 2012 Oct 4. [Epub ahead of print].
- Lane, GJ, Hozack, WJ, Shah, S, Rothman, RH, Booth, RE, Eng, K, Smith, P (1997) Simultaneous bilateral versus unilateral total knee arthroplasty: outcomes analysis. Clin Orthop Relat Res. 345: pp. 106-112 CrossRef
- Liang, K-Y, Zeger, SL (1986) Longitudinal data analysis using generalized linear models. Biometrika. 73: pp. 13-22 CrossRef
- Lie, SA, Engesaeter, LB, Havelin, LI, Gjessing, HK, Vollset, SE (2004) Dependency issues in survival analyses of 55,782 primary hip replacements from 47,355 patients. Stat Med. 23: pp. 3227-3240 CrossRef
- Lohmander, LS (2009) Gerhardsson de Verdier M, Rollof J, Nilsson PM, Engstrom G. Incidence of severe knee and hip osteoarthritis in relation to different measures of body mass: a population-based prospective cohort study. Ann Rheum Dis. 68: pp. 490-496 CrossRef
- Lozano Calderon SA, Shen J, Doumato DF, Zelicof S. Functional outcomes in high-function-demand patients after total knee arthroplasty. Orthopedics. 2012;35:e681–690.
- Mancuso, CA, Ranawat, CS, Esdaile, JM, Johanson, NA, Charlson, ME (1996) Indications for total hip and total knee arthroplasties: results of orthopaedic surveys. J Arthroplasty. 11: pp. 34-46 CrossRef
- March, LM, Cross, M, Tribe, KL, Lapsley, HM, Courtenay, BG, Cross, MJ, Brooks, PM, Cass, C, Coolican, M, Neil, M, Pinczewski, L, Quain, S, Robertson, F, Ruff, S, Walter, W (2004) Arthritis C.O.S.T. Study Project Group. Two knees or not two knees? Patient costs and outcomes following bilateral and unilateral total knee joint replacement surgery for OA. Osteoarthritis Cartilage. 12: pp. 400-408 CrossRef
- McMahon, M, Block, JA (2003) The risk of contralateral total knee arthroplasty after knee replacement for osteoarthritis. J Rheumatol. 30: pp. 1822-1824
- Memtsoudis, SG, Ma, Y, Gonzalez Della Valle, A, Mazumdar, M, Gaber-Baylis, LK, MacKenzie, CR, Sculco, TP (2009) Perioperative outcomes after unilateral and bilateral total knee arthroplasty. Anesthesiology. 111: pp. 1206-1216 CrossRef
- Mont, MA, Mitzner, DL, Jones, LC, Hungerford, DS (1995) History of the contralateral knee after primary knee arthroplasty for osteoarthritis. Clin Orthop Relat Res. 321: pp. 145-150
- Park, KK, Chang, CB, Kang, YG, Seong, SC, Kim, TK (2007) Correlation of maximum flexion with clinical outcome after total knee replacement in Asian patients. J Bone Joint Surg Br. 89: pp. 604-608 CrossRef
- Park, MS, Kim, SJ, Chung, CY, Choi, IH, Lee, SH, Lee, KM (2010) Statistical consideration for bilateral cases in orthopaedic research. J Bone Joint Surg Am. 92: pp. 1732-1737 CrossRef
- Poolman, RW, Kerkhoffs, GM, Struijs, PA, Bhandari, M (2007) International Evidence-Based Orthopedic Surgery Working Group. Don’t be misled by the orthopedic literature: tips for critical appraisal. Acta Orthop. 78: pp. 162-171 CrossRef
- Powell, RS, Pulido, P, Tuason, MS, Colwell, CW, Ezzet, KA (2006) Bilateral vs unilateral total knee arthroplasty: a patient-based comparison of pain levels and recovery of ambulatory skills. J Arthroplasty. 21: pp. 642-649 CrossRef
- Ranstam, J (2002) Problems in orthopedic research: dependent observations. Acta Orthop Scand. 73: pp. 447-450 CrossRef
- Restrepo, C, Parvizi, J, Dietrich, T, Einhorn, TA (2007) Safety of simultaneous bilateral total knee arthroplasty: a meta-analysis. J Bone Joint Surg Am. 89: pp. 1220-1226 CrossRef
- Reuben, JD, Meyers, SJ, Cox, DD, Elliott, M, Watson, M, Shim, SD (1998) Cost comparison between bilateral simultaneous, staged, and unilateral total joint arthroplasty. J Arthroplasty. 13: pp. 172-179 CrossRef
- Ritter, MA, Carr, KD, Keating, EM, Faris, PM (1994) Long-term outcomes of contralateral knees after unilateral total knee arthroplasty for osteoarthritis. J Arthroplasty. 9: pp. 347-349 CrossRef
- Ritter, MA, Harty, LD, Davis, KE, Meding, JB, Berend, M (2003) Simultaneous bilateral, staged bilateral, and unilateral total knee arthroplasty: a survival analysis. J Bone Joint Surg Am. 85: pp. 1532-1537
- Robertsson, O, Ranstam, J (2003) No bias of ignored bilaterality when analysing the revision risk of knee prostheses: analysis of a population based sample of 44,590 patients with 55,298 knee prostheses from the national Swedish Knee Arthroplasty Register. BMC Musculoskelet Disord. 4: pp. 1 CrossRef
- Schwarzer, G, Schumacher, M, Maurer, TB, Ochsner, PE (2001) Statistical analysis of failure times in total joint replacement. J Clin Epidemiol. 54: pp. 997-1003 CrossRef
- Shah, K, Smith, J, Jones, B, Hullin, M (2007) Bilateral total knee replacement under a single anaesthetic, using a cementless implant is not unsafe. Knee Surg Sports Traumatol Arthrosc. 15: pp. 269-275 CrossRef
- Shetty, GM, Mullaji, A, Bhayde, S, Chandra Vadapalli, R, Desai, D (2010) Simultaneous bilateral versus unilateral computer-assisted total knee arthroplasty: a prospective comparison of early postoperative pain and functional recovery. Knee. 17: pp. 191-195 CrossRef
- Sofat, R, Ramkumar, U, Wellsted, D, Parmar, H (2006) Is there a difference between the ability to kneel after unilateral and bilateral total knee replacement?. Acta Orthop Belg. 72: pp. 578-582
- Urban, MK, Chisholm, M, Wukovits, B (2006) Are postoperative complications more common with single-stage bilateral (SBTKR) than with unilateral knee arthroplasty: guidelines for patients scheduled for SBTKR. HSS J. 2: pp. 78-82 CrossRef
- Vaidya, SV, Patel, MR, Panghate, AN, Rathod, PA (2010) Total knee arthroplasty: limb length discrepancy and functional outcome. Indian J Orthop. 44: pp. 300-307 CrossRef
- Ware, JE, Sherbourne, CD (1992) The MOS 36-item short-form health survey (SF-36): I. Conceptual framework and item selection. Med Care. 30: pp. 473-483 CrossRef
- Waters, TS, Bentley, G (2003) Patellar resurfacing in total knee arthroplasty: a prospective, randomized study. J Bone Joint Surg Am. 85: pp. 212-217
- Worland, RL, Jessup, DE, Clelland, C (1996) Simultaneous bilateral total knee replacement versus unilateral replacement. Am J Orthop (Belle Mead NJ). 25: pp. 292-295
- Zeni, JA, Snyder-Mackler, L (2010) Clinical outcomes after simultaneous bilateral total knee arthroplasty: comparison to unilateral total knee arthroplasty and healthy controls. J Arthroplasty. 25: pp. 541-546 CrossRef
- Zhang, Y, Glynn, RJ, Felson, DT (1996) Musculoskeletal disease research: should we analyze the joint or the person?. J Rheumatol. 23: pp. 1130-1134
- Zhang, Y, Xu, L, Nevitt, MC, Aliabadi, P, Yu, W, Qin, M, Lui, LY, Felson, DT (2001) Comparison of the prevalence of knee osteoarthritis between the elderly Chinese population in Beijing and whites in the United States: The Beijing Osteoarthritis Study. Arthritis Rheum. 44: pp. 2065-2071 CrossRef
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- 1. Joint Reconstruction Center, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Republic of Korea
- 2. Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea