| | Total knee arthroplasty effectiveness in patients 55 years old and younger: Osteoarthritis vs. rheumatoid arthritisReceived 27 June 2006; received in revised form 12 October 2006; accepted 29 October 2006. published online 14 December 2006. Abstract In the past, total knee arthroplasty, although very successful, was only indicated for an elderly population. Recently though, several papers have been published confirming that total knee arthroplasty is effective in younger patients. This paper supports the results of those papers. In our study, 207 total knee arthroplasties were performed on patients 55 years old and younger using a posterior cruciate-retaining prosthesis. There was an overall survival rate of 97.6% with an average follow-up of 9.1 years. There were some minor variations in the outcome of the operation based on diagnosis (osteoarthritis vs. rheumatoid arthritis). The success also continued over time with an estimated survival rate of 94.8% at 12 years. Total knee arthroplasty is an effective operation in patients younger then 55 years old. 1. Introduction  Total knee arthroplasty (TKA) has been recognized as an effective way to treat various forms of arthritis for many years now [1], [2], [3], [4], [5], [6]. The operation predictably leads to pain relief and improvement in knee function. Studies with a long-term follow-up have consistently found the operation to be successful over time [3], [4], [6]. In the past, this procedure was only recommended for a more elderly population. This was because some studies found higher rates of failure in patients less then 60 years old [2], [4]. Some investigators discouraged the procedure in younger patients (patients < 55 years old) due to the belief that there was an increased incidence of wear, loosening, and revision in a younger patient population [7]. These fears have proven to be largely unfounded. Several studies in the past decade have shown total knee arthroplasty to be effective in patients younger then 55 years old. These studies found the procedure to be clinically reliable with success rates comparable to those seen in a more elderly population [8], [9], [10], [11], [12], [13], [14]. Duffy et al. found survival rates of 99% at 10 years (63.5% with rheumatoid arthritis and 36.5% with other diagnoses) [10]. Gill et al. found a 96.5% survival rate at 18 years (51.4% with osteoarthritis, 40.3% with rheumatoid arthritis and 8.3% with other diagnoses) [11]. Diduch et al. found a survival rate of 87–94% at 18 years (64% with osteoarthritis and 36% with posttraumatic osteoarthritis) [9]. The purpose of this present study was to validate the effectiveness of TKA in patients 55 years old and younger. The differences in rheumatoid arthritis patients and osteoarthritis patients were investigated as well. To our knowledge, this study includes the largest cohort of patients 55 years old and younger who have undergone TKA. The results were examined with an intermediate follow-up (minimum of 5 years). Knee Society scores, knee function scores, range of motion, knee alignment, and revision rates were investigated to determine the success of the procedure. 2. Materials and methods At the author's institution, there were 8781 total knee replacements performed between July 15, 1974 and June 30, 2000, of which 505 (5.8%) were performed on patients 55 years old and younger. Of these 505 arthroplasties, 473 were primary total knee arthroplasties. There were 41 patients who died within 5 years of surgery and 95 patients with a follow-up of less than 5 years (5 years was the minimum amount of follow-up for inclusion in this study). Of the remaining 337 patients, 50 were lost to follow-up (nine of these 50 died at least 5 years postoperatively). Of the remaining 287 total knee arthroplasties, all patients without an anatomic graduated component (AGC - Biomet Inc., Warsaw, Indiana) prosthesis were excluded (n=67). All patients without a diagnosis of osteoarthritis or rheumatoid arthritis were also excluded (n=13). This left 207 joints in the study. All patients had at least a 5 year follow-up, a diagnosis of osteoarthritis or rheumatoid arthritis, and had a posterior cruciate-retaining prosthesis (AGC). All surgeries were performed by four surgeons. The 207 total knee arthroplasties were performed on 130 patients of whom 90 were female and 40 were male. The mean patient age was 50 (range: 18–55 years). The diagnoses were osteoarthritis (81.6%) and rheumatoid arthritis (18.4%). Of the 169 diagnoses of osteoarthritis, six were cases of posttraumatic osteoarthritis. All patients were followed at 2 months, 6 months, 1 year, and subsequently every 2 years postoperatively. A joint replacement database was used to examine Knee Society scores (KSS) [15], knee function scores, knee alignment, and range of motion both preoperatively and postoperatively. Failure rates were also examined. The average follow-up time was 9.1 years (range: 4.9–20.5 years). Statistics were performed using the SAS statistical package (Cary, NC). The hospital's institutional review board approved this study. 3. Results Of the 207 total knee arthroplasties performed, five had to be revised because of a failed total knee arthroplasty. All of the failures were in patients diagnosed with osteoarthritis. One patient was revised secondary to trauma. She had a posterior cruciate ligament rupture. One patient was revised secondary to ligamentous instability. There were two metal backed patellas that eroded into the femoral component and the polyethylene requiring revision and one revision secondary to mal-alignment and aseptic loosening of the tibial component. The overall average KSS changed from 50.3 preoperatively to 91.2 postoperatively (p<.0001). The overall knee function scores improved from 42.8 to 81.9 (p<.0001). The overall knee range of motion increased from 103.2° to 110.2° (p<.0001) and the alignment changed from 1.1° of valgus to 4.1° of valgus (p<.0001). In the osteoarthritis group, the average KSS changed from 48.7 preoperatively to 92.2 postoperatively (p<.0001). The osteoarthritis group knee function scores improved from 43.6 to 83.0 (p<.0001). The knee range of motion increased from 105.5° to 111.4° (p<.0001) and the alignment changed from .3° of varus to 3.9° of valgus (p<.0001). In the rheumatoid arthritis group, the KSS average improved from 57.2 preoperatively to 87.2 postoperatively (p<.0001). The knee function scores changed from 39.3 to 77.2 (p<.0001). The range of motion increased from 93.1° to 103.2° (p=.1313) and alignment changed from 7.4° of valgus to 5.4° of valgus (p=.4122). When osteoarthritis and rheumatoid arthritis patients were compared, there were some significant differences. Preoperatively, osteoarthritis patients had significantly lower KSS (p=.0039), a higher range of motion (p=.0003), and a more varus alignment (p<.0001) than rheumatoid arthritis patients. Postoperatively, osteoarthritis patients had significantly higher KSS (p=.0143), a higher range of motion (p=.0345), and a less valgus alignment (p=.0116) than the rheumatoid arthritis patients. The osteoarthritis patients had a greater improvement in KSS (p=.0004) and a larger change in alignment (p=.0003) than rheumatoid arthritis patients. A Kaplan–Meier survival curve (Fig. 1) illustrates the survival probability of a total knee arthroplasty in patients 55 years old and younger. The survival rate was 100.0% at 1 year, 99.5% at 3 years, 99.0% at 5 years, 99.0% at 7 years, 96.7% at 10 years, and 94.8% at 12 years. The overall survival rate was 97.6% (average follow-up of 9.1 years). The average time to revision was 6.7 years (range: 2.8–10.9 years). All of the failures were patients with osteoarthritis. This leads to a survival rate of 97.0% for osteoarthritis patients and 100.0% for rheumatoid arthritis patients (p=.1725, Log-Rank) (p=.2526, Wilcoxon). 4. Discussion To our knowledge, this study presents the largest number of total knee arthroplasties performed in patients under 55. Duffy et al. found an estimated survivorship of 99% at 10 years with a study size of 74 (47 rheumatoid arthritis patients included) [10]. Gill et al. found an expected survival rate of 96.5% at 18 years with a study size of 68 (37 osteoarthritis patients and 29 rheumatoid arthritis patients) [11]. Diduch et al. found survival rates of 87–94% at 18 years with a study size of 108 (no rheumatoid arthritis patients included [9]. Our results were similar. We found a 94.8% survival rate at 12 years. There are some weaknesses of this study. The study, by its nature, was a retrospective database review. Also, the survival rate was determined purely by revision rates. Since no radiographic review was performed, there may have been some patients who were impending failures, but who had not yet been revised. There were also 50 patients who were lost to follow-up. Total knee arthroplasty had an acceptable survival rate of 97.6% in our study with an average follow-up of 9.1 years. Our study size included 207 joints with all patients being 55 years old or younger. The operation also led to an increased range of motion and improved Knee Society scores. In our study, the osteoarthritis patients had higher failure rates (not significant), but they also had significantly better KSS improvement (p=.0004). It seems clear that total knee arthroplasty in a younger patient population is a safe and effective operation for patients with both osteoarthritis and rheumatoid arthritis when properly indicated. It should be noted however that younger patients have the potential to place more stress on their implants then an older population does. A study with a longer follow-up period is required to address whether or not younger patients perform well over time. References [1]. [1]Insall JN, Binazzi R, Soudry M, Mestriner LA. Total knee arthroplasty. Clin Orthop Relat Res. 1985;192:13–22. [2]. [2]Knutson K, Lindstrand A, Lidgren L. Survival of knee arthroplasties. A nation-wide multicentre investigation of 8000 cases. J Bone Joint Surg [Br]. 1986;68:795–803. [3]. [3]Ranawat CS, Flynn WF, Saddler S, Hansraj KK, Maynard MJ. Long-term results of the total condylar knee arthroplasty. A 15-year survivorship study. Clin Orthop Relat Res. 1993;286:94–102. [4]. [4]Rand JA, Ilstrup DM. Survivorship analysis of total knee arthroplasty. Cumulative rates of survival of 9200 total knee arthroplasties. J Bone Joint Surg [Am]. 1991;73:397–409. MEDLINE [5]. [5]Sledge CB, Ewald FC. Total knee arthroplasty experience at the Robert Breck Brigham Hospital. Clin Orthop Relat Res. 1979;145:78–84. [6]. [6]Vince KG, Insall JN, Kelly MA. The total condylar prosthesis. 10- to 12-year results of a cemented knee replacement. J Bone Joint Surg [Br]. 1989;71:793–797. [7]. [7]Stulberg SD. Bi/tri-compartmental degenerative knee disease in the young patient. Orthopedics. 1995;18:899–901. MEDLINE [8]. [8]Dalury DF, Ewald FC, Christie MJ, Scott RD. Total knee arthroplasty in a group of patients less than 45 years of age. J Arthroplasty. 1995;10:598–602. Abstract |
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[11]. [11]Gill GS, Chan C, Mills DM. 5- to 18-year follow-up study of cemented total knee arthroplasty for patients 55 years old or younger. J Arthroplasty. 1997;12:49–54. Abstract |
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[14]. [14]Parvizi J, Lajam CM, Trousdale RT, Shaughnessy WJ, Cabanela ME. Total knee arthroplasty in young patients with juvenile rheumatoid arthritis. J Bone Joint Surg [Am]. 2003;85:1090–1094. [15]. [15]Ewald FC. The Knee Society total knee arthroplasty roentgenographic evaluation and scoring system. Clin Orthop Relat Res. 1989;248:9–12. Center for Hip and Knee Surgery, St. Francis Hospital, 1199 Hadley Road, Mooresville, IN 46158, United States  Corresponding author. Tel.: +1 317 831 2273; fax: +1 317 831 9347.
PII: S0968-0160(06)00185-2 doi:10.1016/j.knee.2006.10.010 © 2007 Elsevier B.V. All rights reserved. | |
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