3. RESEARCH
by performing KaplanâMeier survival analysis with SPSS and it was revised to 4.1° at the last follow-up. When the
statistical software, with failure defined as removal or revi- radiolucent lines of each component were examined,
sion of any component for any reason. 23 knees (12.8%) were observed to have radiolucent lines
The statistical significance of the change according to in the femoral components at the last follow-up, and their
the passage of time from the preoperative status to the last widths were 2 mm or less in all cases. Forty-three knees
follow-up was analyzed using a paired t test, and the com- (24%) had radiolucent lines in the tibial components, and
parison of the result of the last follow-up in each group was these were seen on the anteroposterior view in 32 cases and
done using an unpaired t test. We considered results to be on the lateral view in 11 cases (Table 1). The lines were
significant at p < 0.05. 2 mm in width on 6 of the 32 knees with radiolucent lines
on the anteroposterior view and 1 of the 11 knees with
RESULTS radiolucent lines on the lateral view, and loosening had
developed in 1 knee 8.4 years postoperatively. Twelve of
We included 131 patients who underwent 202 cementless 179 knees (6.7%) showed radiolucencies both in the
TKAs for rheumatoid arthritis in our study. Nineteen femoral and tibial components. There were no radiolucent
patients (23 cases) were lost to follow-up, and the remain- lines in the patellar components. At the last follow-up the
ing 112 patients (179 cases; 89% of the 202 eligible cases) average width of radiolucent lines was 1.4 mm, and 1 knee
were available for clinical and radiographic evaluation showed a radiolucent line of 5 mm or more.
after surgery. There were 11 men (16 cases) and 101 wo- Based on the Knee Society clinical rating system, the
men (163 cases) with a mean age of 62.3 (range 38.5â73.4) knee score increased from a mean of 47.5 points preopera-
years and a mean body mass index (BMI) of 23.8 (range tively to a mean of 91.2 points at the last follow-up, and the
18.4â29.3). Three patients were in their 30s, 14 were in mean function score improved from an average of
their 40s, 43 were in their 50s, 37 were in their 60s and 15 43.6 points preoperatively to 82.3 points at last follow-up
were in their 70s. Sixty-seven patients underwent bilateral (p = 0.032; Fig. 1, Table 2). At the last follow-up, the knee
surgery, and 45 patients underwent unilateral surgery. scores showed good or excellent results in 166 knees
A previous operation, including open or arthroscopic (92.7%) and the function scores showed good or excellent
synovectomies of their knees, had been performed in results in 163 knees (91.1%; Table 3).
18 patients (21 knees). We used the Tricon-M prosthesis During the follow-up period, subsidence of the tibial
in 39 knees, the Genesis in 58 knees and the Advantim in prosthesis was seen on radiographs obtained 3 months
82 knees. The mean follow-up period in our study was postoperatively for 19 knees (6 with the Tricon-M, 7 with
10.1 (range 4.6â15.5) years.
Radiologically, on the anteroposterior radiographs 100
91.2
Preoperative
taken immediately after surgery, the mean femoral flexion Postoperative 82.3
80
angle (α) was 97.5° and the mean tibial angle (ÎČ) was 89.2°.
On the lateral radiographs, the mean femoral flexion angle 60
Score
47.5
(γ) was 1.6°, the mean tibial angle (Ύ) was 89.2°, and the 43.6
40
mean total valgus angle ⊠was 6.7°. At the last follow-up,
the mean α angle was 97.4°, the mean ÎČ angle was 89.1°, 20
the mean γ angle was 1.4°, the mean Ύ angle was 89.0°, and
0
the mean ⊠angle was 6.5°. Comparing the values obtained Knee Function
at last follow-up with those obtained immediately after Scale
surgery, we detected no significant differences, and there Fig. 1. Average scores were improved at the last follow-up using
were no significant differences between the components. the Knee Society clinical rating system, compared with the pre-
The mean preoperative femorotibial angle was varus 4.7°, operative condition.
Table 1. Radiolucent line of each component based on the Knee Society radiographic evaluation and scoring system for
112 patients who underwent 179 cementless total knee arthroplasties from March 1990 to February 2000
Zone
1 2 3 4 5 6 7
Average
Prosthesis thickness, mm T G A T G A T G A T G A T G A T G A T G A
Femur 1.2 2 2 2 2 1 1 2 1 2 1 2 1 1 1 1 1
Tibia, anteroposterior view 1.6 6 6 5 3 4 3 1 2 1 1
Tibia, lateral view 1.4 2 2 3 1 2 1
A = Advantim; G = Genesis; T = Tricon-M.
Can J Surg, Vol. 54, No. 3, June 2011 181
5. RESEARCH
the correction of the valgus deformity has an effect on the bone inevitably occurs for cemented and cementless com-
success rate. It has been reported that it is desirable to ponents. Therefore, during cementless TKA the tibial tray
obtain about 7° valgus of the femorotibial angle.21,22 Total should cover the bone cut as much as possible, and a boneâ
knee arthroplasty using a PCL-retaining prosthesis in prosthesis index larger than 0.8 should be achieved to pre-
patients with rheumatoid arthritis could induce posterior vent subsidence.26 Furthermore, both biomechanical27 and
instability or genu recurvatum deformity.23 In our study, clinical28 investigations have supported the importance of a
the mean knee score was 91.2 points, and the mean func- central tibial stem for better primary stability of fixation.
tion score was 82.3 points; theses scores are similar or bet- Trieb and colleagues29 reported good clinical and radio-
ter results compared with those reported in previous stud- logic results in patients with rheumatoid arthritis without
ies.5,12 The mean 6.5° valgus angle of the femorotibial angle preference for the method of fixation or the patientâs
was well-maintained at the last follow-up, and instability or weight. We performed 4 revision surgeries during our
genu recurvatum deformity was not observed. follow-up period, but 2 of them were owing to infections.
Radiolucent lines observed around components are still As a whole, the present study showed clinically and radiolog-
open to dispute, but they are an important part of evaluat- ically good results in more than 90% of the knees. It is
ing the results of TKA in most patients.24,25 Ecker and col- thought that the relatively low survival rate of the Tricon-M
leagues24 reported that there was no statistically significant group compared with other groups was because of the
correlation between the occurrence of thin radiolucent lines small number of cases and the long follow-up period.
in any location and the eventual postoperative clinical result
and that radiolucent lines greater than 2 mm were associ- CONCLUSION
ated with poor results. In our study, there were no radiolu-
cent lines around patellar components, and we observed The decision to use cement or not during TKA in patients
radiolucent lines in 12.8% of femoral components and 24% with rheumatoid arthritis can be made according to the
of tibial components. The mean width of radiolucent lines surgeonsâ experience and the patientsâ conditions. Our
was 1.4 mm, and they were meaningless and nonprogressive study revealed a final prosthesis survival rate of 96.8% at
in all but 1 knee, which showed late subsidence and loosen- the 15.5-year follow-up, and there were no serious com-
ing and required revision surgery. plications according to the radiologic and clinical evalua-
In our study, the subsidence of the tibial component up tions. We think the cementless technique of TKA for
to an average of 2.4 mm at 1 year postoperatively was patients with rheumatoid arthritis is also effective to
observed in 19 knees, and aseptic loosening had developed relieve pain and to improve the function of the knee joint
in 1 knee. When performing TKA, prosthesis migration in without serious complications.
Competing interests: None declared.
1.0
0.968
Contributors: Drs. Woo and Lee designed the study. All authors
acquired the data, which Drs. Kim, Chung and Lee analyzed. Drs. Woo
0.8 and Kim wrote the article, which Drs. Chung and Lee reviewed. All
authors approved its publication.
Survival rate
0.6
References
0.4
1. Wolfe F, Zwillich S. The long-term outcomes of rheumatoid arthritis.
0.2 Arthritis Rheum 1998;41:1072-82.
2. Goldberg VM, Figgie MP, Figgie HE, et al. Use of total condylar knee
0.0
prosthesis for treatment of osteoarthritis and rheumatoid arthritis.
0 3 6 9 12 15 J Bone Joint Surg Am 1988;70:802-11.
Follow-up, yr
3. Moon MS, Woo YK, Lee KH. Total knee replacement surgery for
rheumatoid and osteoarthritic patients. Comparative study. J Korean
Cumulate proportion Orthop Assoc 1991;26:1165-73.
No.
surviving at the time
Follow-up remaining
time, yr cases 4. Rand JA, Ilstrup DM. Survivorship analysis of total knee arthroplasty.
Estimate Standard error
Cumulative rates of survival of 9200 total knee arthroplasties. J Bone
4.6 0.994 0.006 178 Joint Surg Am 1991;73:397-409.
6.8 0.989 0.008 177
8.4 0.983 0.010 160
5. Aglietti P, Buzzi R, Segoni F, et al. Insall-Burnstein posterior-stabilized
prosthesis in rheumatoid arthritis. J Arthroplasty 1995;10:217-25.
10.5 0.968 0.018 65
6. Hsu RW, Fan GF, Ho WP. A follow-up study of porous coated
anatomic knee arthroplasty. J Arthroplasty 1995;10:29-36.
Fig. 2. KaplanâMeier survivorship analysis shows 96.8% survival
at the postoperative 15.5-year follow-up. 7. Font-Rodriguez DE, Scuderi GR, Insall JN. Survivorship of cemented
Can J Surg, Vol. 54, No. 3, June 2011 183
6. RECHERCHE
total knee arthroplasty. Clin Orthop Relat Res 1997;345:79-86. 19. Stuart MJ, Rand JA. Total knee arthroplasty in young adults who
have rheumatoid arthritis. J Bone Joint Surg Am 1988;70:84-7.
8. Dalury DF, Ewald FC, Christie MJ, et al. Total knee arthroplasty in
group of patients less than 45 years of age. J Arthroplasty 1995;10: 20. Wright RJ, Lima J, Scott RD, et al. Two- to four-year results of pos-
598-602. terior cruciate sparing condylar total knee arthroplasty with an un-
cemented femoral component. Clin Orthop Relat Res 1990;260:80-6.
9. Rodriguez JA, Saddler S, Edelman S, et al. Long-term results of total
knee arthroplasty in class 3 and 4 rheumatoid arthritis. J Arthroplasty 21. Lewallen DG, Bryan RS, Peterson LF. Polycentric total knee arthro-
1996;11:141-5. plasty. A ten-year follow-up study. J Bone Joint Surg Am 1984;66:1211-8.
10. Gill GS, Chan KC, Mills DM. 5- to 18-year follow-up study of 22. Mokris JG, Smith SW, Anderson SE. Primary total knee arthroplasty
cemented total knee arthroplasty for patients 55 years old or younger. using genesis total knee arthroplasty system. 3- to 6-year follow-up
J Arthroplasty 1997;12:49-54. study of 105 knees. J Arthroplasty 1997;12:91-8.
11. Hungerford DS, Krackow KA, Kenna RV. Cementless total knee 23. Laskin RS. Total knee replacement with posterior cruciate ligament
replacement in patients 50 years old and under. Orthop Clin North Am retention in rheumatoid arthritis. Problems and complications. Clin
1989;20:131-45. Orthop Relat Res 1997;345:24-8.
12. Armstrong RA, Whiteside LA. Results of cementless total knee 24. Ecker ML, Lotke PA, Windsor RE, et al. Long-term results after
arthroplasty in older rheumatoid arthritis population. J Arthroplasty total condylar knee arthroplasty â significance of radiolucent lines.
1991;6:357-62. Clin Orthop Relat Res 1987;216:151-8.
13. Stuchin SA, Ruoff M, Matarese W. Cementless total knee arthro- 25. Ejsted R, Hindso K, Mouritzen V. The total condylar knee prosthesis
plasty in patients with inflammatory arthritis and compromised bone. in osteoarthritis. A 5- to 10-year follow-up. Arch Orthop Trauma Surg
Clin Orthop Relat Res 1991;273:42-51. 1994;113:61-5.
14. Laskin RS. Total knee arthroplasty using an uncemented, polyethylene 26. Nielsen PT, Hansen EB, Rechnagel K. Cementless total knee arthro-
tibial implant. A seven-year follow-up study. Clin Orthop Relat Res plasty in unselected cases of osteoarthritis and rheumatoid arthritis: a
1993;288:270-6. 3-year follow-up study of 103 cases. J Arthroplasty 1992;7:137-43.
15. Insall JN, Dorr LD, Scott RD, et al. Rationale of the knee society
27. Yoshii I, Whiteside LA, Milliano MT, et al. The effect of central stem
clinical rating system. Clin Orthop Relat Res 1989;248:13-4.
and stem length on micromovement of the tibial tray. J Arthroplasty
16. Illgen R, Tueting J, Enright T, et al. Hybrid total knee arthroplasty: 1992;7:433-8.
a retrospective analysis of clinical and radiographic outcomes at aver-
28. Albrektsson BE, Ryd L, Carlsson LV, et al. The effect of a stem on the
age 10 years follow-up. J Arthroplasty 2004;19:95-100.
tibial component of knee arthroplasty. A roentgen stereophotogram-
17. Ewald FC. The Knee Society total knee arthroplasty roentgeno- metric study of uncemented tibial components in the Freeman-
graphic evaluation and scoring system. Clin Orthop Relat Res 1989; Samuelson knee arthroplasty. J Bone Joint Surg Br 1990;72:252-8.
248:9-12.
29. Trieb K, Schmid M, Stulnig T, et al. Long-term outcome of total
18. Sledge CB, Walker PS. Total knee arthroplasty in rheumatoid arthritis. knee replacement in patients with rheumatoid arthritis. Joint Bone
Clin Orthop Relat Res 1984;182:127-36. Spine 2008;75:163-6.
THE MACLEANâMUELLER PRIZE
ATTENTION: RESIDENTS AND SURGICAL DEPARTMENT CHAIRS
Each year the Canadian Journal of Surgery offers a prize of $1000 for the best manuscript written by a Cana-
dian resident or fellow from a specialty program who has not completed training or assumed a faculty posi-
tion. The prize-winning manuscript for the calendar year will be published in an early issue the following year,
and other submissions deemed suitable for publication may appear in a subsequent issue of the Journal.
The resident should be the principal author of the manuscript, which should not have been submitted or
published elsewhere. It should be submitted to the Canadian Journal of Surgery no later than Oct. 1.
Send submissions to: Dr. G.L. Warnock, Coeditor, Canadian Journal of Surgery, Department of Surgery, UBC,
910 West 10th Ave., Vancouver BC V5Z 4E3.
o
184 J can chir, Vol. 54, N 3, juin 2011