Published online Oct 31, 2011.
https://doi.org/10.4055/jkoa.2011.46.5.405
Total Knee Replacement Arthroplasty with NexGen®-LPS: Minimum 5 Year Follow-up Results
Abstract
Purpose
One hundred and thirty-six patients who underwent total knee replacement arthroplasty (TKRA) with NexGen®-LPS were analyzed for the clinical and radiologic results after a minimum follow-up of 5-years.
Materials and Methods
This study included 136 patients (209 knees) who underwent TKRA with NexGen®-LPS between August 1998 and February 2005 and had a minimum follow-up of 5 years. We evaluated the range of motion (ROM), American Knee Society knee functional scores, radiographic results and complication rates in the study subjects with an average 8.3 years of follow-up (range: 5-11.5 years). We also compared the results of the degenerative arthritis group (195 knees in 129 patients) with those of the rheumatoid arthritis group (14 knees in 7 patients).
Results
The mean ROM increased from 107.3° to 122° at the final follow-up. The flexion contracture also improved from 8.3° to 1.2° at final follow-up. The knee score improved from 51 to 94.7 at the final follow-up. The functional score improved from 38 to 84.2 (p<0.05) at final follow-up. There was no statistical significant difference in the results between the degenerative arthritis and rheumatoid arthritis groups (p>0.05). Valgus (α), varus (β), flexion (γ) and the posterior slope angle (δ) of the tibial components were well maintained both during the immediate postoperative period and at the final follow-up. There was no significant difference in the tibiofemoral angle and α, β, γ and δ angle (p>0.05) between the degenerative arthritis and rheumatoid arthritis groups. The alignment of the alternative substance was also relatively well maintained. Radiolucent lines were observed in 39 knees (18.7%), and in 42 zones out of 209 knees. The most common site of radiolucent lines was the medial side of the tibia in 21 knees. The overall incidence of radiolucent lines was 15% for the femur, 61% for the tibia and 24% for the patella. There was no statistically significant difference between the presence of radiolucent lines and the clinical results (p>0.05). There was 1 case of revision surgery due to loosening of implants at 8 years after surgery, but no early loosening was observed in the study subjects. Complications were found in 6 patients. Two patients with early postoperative infection were treated with revision surgery. Two patients with acute hematogenous infection 4 years after the initial operation were treated with revision surgery. Two patients with superficial infection were treated with antibiotics and regular dressing.
Conclusion
The patients treated with the NexGen®-LPS TKRA had a decreased level of postoperative pain and an improved knee joint ROM. A lower rate of complications was also found with this type of implant.
Figure 1
This diagram shows radiological evaluation and scoring system after TKRA.
Figure 2
Right anteroposterior knee radiograph shows radiolucent line (arrow).
Figure 3
(A) Right knee anteroposterior and lateral radiographs show a loose tibial implant with bone loss on the medial side of the tibia. (B) Radiographs after revision total knee arthroplasty.
Table 1
Comparative Clinical Results between the Osteoarthritis Group (OA) and the Rheumatoid Arthritis Group (RA)
Table 2
Radiologic Results according to Disease
Table 3
Results of Radiolucent Line Analysis according to Region
References
-
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.
-
-
Kavolus CH, Ritter MA, Keating EM, Faris PM. Survivorship of cementless total knee arthroplasty without tibial plateau screw fixation. Clin Orthop Relat Res 1991;273:170–176.
-
-
Han CD, Shin SJ, Han DY. Radiologic analysis of cement-less total knee arthroplasty-comparative studies in osteoarthritis, rheumatoid arthritis. J Korean Knee Soc 1996;8:42–53.
-
-
Moon MS, Woo YK, Lee KH. Total knee replacement surgery for rheumatoid and osteoarthritic patients (comparative study). J Korean Orthop Assoc 1991;26:1165–1173.
-
-
Ritter MA, Gioe TJ, Stringer EA, Littrell D. The posterior cruciate condylar total knee prosthesis. A five-year follow-up study. Clin Orthop Relat Res 1984;184:264–269.
-
-
Scott RD, Volatile TB. Twelve years' experience with posterior cruciate-retaining total knee arthroplasty. Clin Orthop Relat Res 1986;205:100–107.
-
-
Insall JN, Lachiewicz PF, Burstein AH. The posterior stabilized condylar prosthesis: a modification of the total condylar design. Two to four-year clinical experience. J Bone Joint Surg Am 1982;64:1317–1323.
-
-
Scott WN, Rubinstein M, Scuderi G. Results after knee replacement with a posterior cruciate-substituting prosthesis. J Bone Joint Surg Am 1988;70:1163–1173.
-
-
Dorr LD, Boiardo RA. Technical considerations in total knee arthroplasty. Clin Orthop Relat Res 1986;205:5–11.
-
-
Kraay MJ, Meyers SA, Goldberg VM, Figgie HE 3rd, Conroy PA. "Hybrid" total knee arthroplasty with the Miller-Galante prosthesis. A prospective clinical and roentgenographic evaluation. Clin Orthop Relat Res 1991;273:32–41.
-
-
Leone JM, Hanssen AD. Management of infection at the site of a total knee arthroplasty. J Bone Joint Surg Am 2005;87:2335–2348.
-
-
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.
-