Increased risk of early and medium-term revision after post-fracture total knee arthroplasty

Figures & data

Table 2. Patient characteristics

	< 50 years		50–70 years		> 70 years
Characteristics	PTFA	OA	PTFA	OA	PTFA	OA
Observations	227 (14%)	1.377 (86%)	771 (3%)	24,259 (97%)	423 (2%)	25,461(98%)
Mean follow-up, years
(range, days–years)	6.1 (19–16.2)	4.6 (14–16.7)	6.0 (20–16.9)	5.2 (1–17)	5.8 (2–16.8)	5.1 (1–17)
Revisions^a	50 (22%)^e	154 (11%)^e	80 (10%)	1,390 (6%)	29 (7%)	817 (3%)
Mean age^b	42 (SD 6)^e	46 (SD 4)^e	60 (SD 6)^e	62 (SD 5)^e	77 (SD 5)	77 (SD 5)
Sex^a
Female	88 (39%)^e	854 (62%)^e	408 (53%)^e	14,670 (60%)^e	311 (74%)^d	16,899 (66%)^d
Fracture
Femoral	63 (28%)	NA	170 (22%)	NA	67 (16%)	NA
Tibial	164 (72%)	NA	601 (78%)	NA	356 (84%)	NA
Weight, kg^b	83 (SD 23)^e	92 (SD 21)^e	81 (SD 21)^e	88 (SD 20)^e	73 (SD 20)^e	79 (SD 18)^e
Charnley class, n^a
A	207 (91%)^e	796 (58%)^e	610 (79%)^e	10,710 (45%)^e	292 (69%)^e	10,639 (42%)^e
B1	10 (4.5%)^e	350 (25%)^e	76 (10%)^e	8,351 (34%)^e	50 (12%)^e	8,715 (34%)^e
B2	1 (0.5%)^e	158 (12%)^e	18 (2%)^e	3,971 (16%)^e	14 (3%)^e	4,327 (17%)^e
C	9 (4%)^e	73 (5%)^e	67 (9%)^e	1,227 (5%)^e	67 (16%)^e	1,780 (7%)^e
Mean duration of
primary surgery, min^b	102 (SD 33)^e	73 (SD 24)^e	96 (SD 38)^e	73 (SD 22)^e	94 (SD 33)^e	72 (SD 21)^e
Perioperative complications^a	2 (1%)	10 (1%)	28 (3.5%)^e	158 (0.5%)^e	10 (2.5%)^e	201 (1%)^e
Component supplementation^b	43 (19%)^e	24 (1.5%)^e	129 (17%)^e	504 (2%)^e	92 (22%)^e	546 (2%)^e

a Wilcoxon rank-sum test.

b Chi-square test or Fisher’s exact test.

Level of significance: ^c p < 0.05, ^dp < 0.01, ^ep < 0.001.

Figure 1. Survival estimation by Kaplan-Meier method for TKA inserted due to PTFA (red line) and due to primary OA (blue line).

A. Patients younger than 50 years. A significant difference was found by log-rank test (p = 0.001). The estimated survival in the PTFA group at 1, 5, and 10 years following primary operation was 0.93 (CI: 0.88–0.95), 0.82 (CI: 0.76–0.86), and 0.72 (CI: 0.64–0.79), respectively. Similarly, the corresponding survival rates in the OA group were 0.97 (CI: 0.96–0.98), 0.88 (CI: 0.86–0.89), and 0.83 (CI: 0.80–0.86).

B. Patients aged between 50 and 70 years. A significant difference was found by log-rank test (p < 0.001). The estimated survival at 1, 5, and 10 years following primary operation in the PTFA group was 0.97 (CI: 0.96–0.98), 0.90 (CI: 0.87–0.92), and 0.86 (CI: 0.83–0.89). Similarly, the 1-, 5-, and 10-year survival in the OA group was 0.98 (CI: 0.98–0.99), 0.94 (CI: 0.94–0.95), and 0.91 (CI: 0.91–0.92).

C. Patients aged more than 70 years. A significant difference was found by log-rank test (p < 0.001). The estimated survival at 1, 5, and 10 years following primary operation in the PTFA group was 0.97 (CI: 0.95–0.99), 0.93 (CI: 0.89–0.95), and 0.91 (CI: 0.87–0.94). Similarly, the 1-, 5-, and 10-year survival in the OA group was 0.99 (CI: 0.98–0.99), 0.97 (CI: 0.96–0.97), and 0.95 (CI: 0.95–0.96).