Early outcomes of patella resurfacing in total knee arthroplasty

Figures & data

Figure 1.  Cumulative percent revision (CPR) of primary total knee arthroplasty by patella resurfacing.

Table 1.  Annual cumulative percent revision (CPR) of primary total knee arthroplasty by patella resurfacing

Patella resurfacing at primary operation	Cumulative percent revision after
	1 year	2 years	3 years	4 years	5 years
Non-resurfaced patella (NR)	1.2 (1.1–1.2)	2.5 (2.3–2.6)	3.1 (3.0–3.3)	3.6 (3.5–3.8)	4.0 (3.9–4.3)
Resurfaced patella (R)	0.9 (0.8–1.0)	1.7 (1.6–1.9)	2.3 (2.1–2.4)	2.8 (2.6–3.0)	3.1 (2.9,–3.3)

Table 2.  Reason for revision of primary total knee arthroplasty by patella resurfacing

Reason for revision ^a	Non-resurfaced patella (NR)		Resurfaced patella (R)		Total
	N	%	N	%	N	%
Loosening	606	29	421	36	1,027	31
Infection	389	19	323	28	712	22
Patellofemoral pain	361	17	13	1.1	374	11
Pain	270	13	82	7.0	352	11
Instability	97	4.6	59	5.0	156	4.8
Arthrofibrosis	78	3.7	55	4.7	133	4.1
Fracture	37	1.8	45	3.8	82	2.5
Malalignment	38	1.8	27	2.3	65	2.0
Dislocation	14	0.7	10	0.9	24	0.7
Patella maltracking	15	0.7	7	0.6	22	0.7
Wear, patella	19	0.9	1	0.1	20	0.6
Bearing/dislocation	10	0.5	9	0.8	19	0.6
Other	163	7.8	119	10	282	8.6
Total	2,097	100	1,171	100	3,268	100

^a Some patients had multiple diagnoses.

Figure 2.  Cumulative percent revision (CPR) comparing patella resurfacing at primary surgery with non-resurfacing at primary surgery revised for patella resurfacing

Table 3.  Type of revision for primary total knee arthroplasty comparing the use of patella resurfacing and no resulfacing

Type of revision	Non-resurfaced patella (NR)		Resurfaced patella (R)		Total
	N	%	N	%	N	%
Tibial and femoral	336	17	340	31	676	22
Patella only	566	29	65	6.0	631	21
Insert only	323	16	277	25	600	20
Tibial only	184	9.3	172	16	356	12
Femoral only	242	12	114	10	356	12
Insert and patella	214	11	19	1.7	233	7.6
Cement spacer	73	3.7	71	6.5	144	4.7
Other minor components	20	1.0	15	1.4	35	1.1
Removal of prosthesis	19	1.0	15	1.4	34	1.1
Fusion nail	1	0.1	2	0.2	3	0.1
Reinsertion of components	1	0.1	2	0.2	3	0.1
Total	1,979	100	1,092	100	3,071	100

Table 4.  Annual cumulative percent revision (CPR) of primary total knee arthroplasty by patella resurfacing and primary diagnosis

		Cumulative percent revision after
Patella usage	Primary diagnosis	1 year	2 years	3 years	4 years	5 years
Non-resurfaced patella	Osteoarthritis	1.2 (1.1–1.2)	2.4 (2.3–2.6)	3.1 (3.0–3.3)	3.6 (3.4–3.8)	4.0 (3.8–4.2)
Non-resurfaced patella	Other diagnosis	1.2 (0.8–1.8)	2.9 (2.2–3.8)	3.5 (2.7–4.5)	4.5 (3.5– 5.7)	4.9 (3.8–6.3)
Resurfaced patella	Osteoarthritis	0.9 (0.8–1.0)	1.8 (1.6–1.9)	2.3 (2.2–2.5)	2.8 (2.6–3.0)	3.1 (2.9–3.3)
Resurfaced patella	Other diagnosis	0.5 (0.3–0.9)	1.1 (0.7–1.7)	1.7 (1.2–2.5)	2.2 (1.5–3.2)	2.6 (1.8–3.9)