Outcome of revision of unicompartmental knee replacement

Figures & data

Table 1.  Age and sex distribution of subjects by type of primary knee replacement at the time of revision of the primary

“Revision of primary” by sex		Age (years) ^a
		n (%)	Q1	Median	Q3	Mean	SD
UKA	Male	980 (48)	58	64	72	65	9.9
	Female	1,072 (52)	57	65	73	65	10
TKA	Male	2,521 (47)	61	67	74	67	10
	Female	2,885 (53)	61	68	75	68	10
Total		7,458	59	67	74	67	10

^a Q1, Q3 are first and third quartiles of the age distribution.

Table 2.  Indications for revision of primary UKA and TKA

Revision diagnosis	UKA		TKA
	n	%	n	%
Loosening/Lysis	1,035	50	1,707	32
Infection	104	5.1	1,253	23
Pain	254	12	500	9.2
Patello femoral pain	13	0.6	705	13
Progression of disease	354	17	32	0.6
Other	292	14	1,209	22
Total	2,052	100	5,406	100

Table 3.  Annual cumulative percent revision of “revision of primary” knee replacement (excluding infection) (95% CI)

CPR	1 year	2 years	3 years	4 years	5 years
UKA to UKA minor	16 (11–24)	29 (21–38)	30 (22–40)
UKA to UKA major	11 (6.8–16)	23 (17–30)	28 (22–36)	31 (24–39)
UKA to TKA	3.0 (2.2–4.0)	7.1 (5.8–8.7)	10 (8.3–12)	13 (11–15)	15 (12–18)
TKA to TKA	3.6 (2.5–5.2)	8.0 (6.1–10)	12 (9.0–15)	14 (11–18)	18 (14–22)

Figure 1.  Cumulative percent revision of “revision of primary” UKA (excluding infection).

Figure 2.  Cumulative percent revision of “revision of primary” knee replacement (excluding infection).

Table 4.  “Revision of primary” knee replacement: re-revision diagnosis

Re-revision diagnosis	UKA to UKA minor		UKA to UKA major		UKA to TKA		TKA to TKA
	n	%	n	%	n	%	n	%
Loosening/lysis	17	46	27	52	63	46	34	42
Infection	2	5.4	5	9.6	19	14	25	31
Pain	6	16.2	6	11.5	18	13	8	9.9
Patello femoral pain	1	2.7	1	1.9	9	6.5	3	3.7
Progression of disease	2	5.4	7	14	3	2.2
Other	9	24.3	6	12	26	19	11	13
Total	37	100	52	100	138	100	81	100