284 press-fit Kinemax total knee arthroplasties followed for 10 years: Poor survival of uncemented prostheses

Figures & data

Figure 1. Flow chart representing follow-up for patients who had Kinemax knee replacement at least 10 years previously, and showing when knees were censored or listed as having failed.

Table 1.  Indications for revision surgery and reoperations

Reason for revision	No.
Aseptic failures
Loosening – tibia	10
Loosening – femur	13
Loosening of both components	6
Polyethylene wear	6
Instability	2
Infections and complications requiring reoperation
Infection	2
Patella resurfacing (previously unresurfaced)	1
Patella pain	1
Lack of flexion	2
Adhesive capsulitis	1
Pain	1
Unknown	4
Total	49

Figure 2. Kaplan-Meier Survival estimates with 95% confidence intervals for uncemented and cemented knees using date of revision surgery as an endpoint for failures.

Table 2.  Bivariate analysis for aseptic failures resulting in revision surgery

	Estimated 10–year survivorship (%) (95% CI)	P-value(log-rank test)
Total group	84(78–88)
Femur fixation
Uncemented	77(67–84)	0.003
Cemented	90(79–95)
Tibia fixation
Uncemented	76(67–83)	< 0.001
Cemented	93(82–97)
Femur and tibia fixation
One or both uncemented	77 (67–83)	< 0.001
Both cemented	93(81–97)
Age at time of surgery
< 60 years	77(67–83)	0.004
> 60 years	92(82–97)
Diagnosis
OA	89(80–94)	0.04
RA/JCA	77(67–85)

Table 3.  Survivorship analysis by accumulated risk factors for aseptic failures resulting in revision surgery

Risk factor group Age (years) and fixation^a	No. of knees	No. of aseptic failures	Estimated 10–year survivorship (%) (95% CI)
Group 1	77	2	94 (77–99)
≥ 60, cemented^a
Group 2	27	2	90 (66–98)
≤ 60, cemented^a
Group 3	50	6	89 (68–97)
> 60, uncemented^a
Group 4	96	27	71 (60–80)
< 60, uncemented^a
Total	250	37

^aBoth components