Registration completeness in the Norwegian Arthroplasty Register

Figures & data

Table 1.  Comparison of the number of joint replacements reported to the Norwegian Arthroplasty Register (NAR) and to the Norwegian Patient Register (NPR), 1999–2002

	NAR			NPR			% of NPR ^a					% of NPR ^a (incl. “99” codes)
Joint	Prim ^b	R-e ^b	R-r ^b	Prim ^b	R-e ^b	R-r ^b	All	Prim ^b	R-all ^b	R-e ^b	R-r ^b	Prim ^b	R-e ^b
Hip	23,376	3,552	222	24,224	3,269	292	98	97	106	109	76	96	102
Knee	7,905	669	65	7,962	649	105	99	99	97	103	62	99	96
Ankle	108	14	2	131	20	20	73	82	40	70	10	86 ^d	85 ^d
Toe	258	47	13	280	50	32	88	92	73	94	41
Shoulder	595	56	10	669	74	33	85	89	62	76	30	87	66
Elbow	158	48	11	181	54	20	85	87	80	89	55	85	81
Wrist	64	1	6	123	35	15	41	52	14	2.8	40	85^e	76 ^e
Hand ^c	395	96	2	338	79	23	112	117	96	122	8.7
All	32,859	4,483	331	33,908	4,230	540	97	97	101	106	61	96	99

^aRegistration completeness calculated as a percentage with the number of joint replacements reported to the NAR as numerator and the number reported to the NPR as denominator.

^bPrim – primary operations; R-all – all revisions R-e – revisions with exchange of at least one component; R-r – revisions with removal of at least one component (without insertion of a new prosthesis).

^cIncludes replacement of joints in the finger and the carpometacarpal (CMC I) joint.

^dSeparate statistics could not be established for ankle and toe joint replacements due to common codes for unspecified implant operations (“99” codes).

^eSeparate statistics could not be established for wrist and hand (finger and CMC I) replacements due to common codes for unspecified implant operations (“99” codes).

Table 2.  Comparison of the number of joint replacements reported to the Norwegian Arthroplasty Register (NAR) and the Norwegian Patient Register (NPR) by year of operation, 1999–2002

	NAR		NPR		% of NPR ^a
Joint Year	P ^b	R ^b	P ^b	R ^b	All	P ^b	R ^b
Hip
1999	5,464	941	5,560	928	99	98	101
2000	5,691	974	5,891	858	99	97	114
2001	6,108	916	6,378	893	97	96	103
2002	6,113	943	6,395	882	97	96	107
Knee
1999	1,592	153	1,582	154	101	101	99
2000	1,872	169	1,887	174	99	99	97
2001	2,190	194	2,212	211	98	99	92
2002	2,251	218	2,281	215	99	99	101

^aRegistration completeness calculated as a percentage with the number of joint replacements reported to the NAR as numerator and those reported to the NPR as denominator.

^bP – primary operations; R – revisions.

Table 3.  Number of joint replacements reported to the Norwegian Patient Register (NPR) with unspecified operation codes (“99” codes), 1999–2002

	Primary		Exchange revision
Joint	NPR	Code 99 (%)	NPR	Code 99 (%)
Hip	24,280	56 (0.2)	3,484	215 (6.1)
Knee	8,024	62 (0.7)	696	47 (6.7)
Ankle and toe ^a	426	15 (3.5)	72	2 (2.7)
Shoulder	683	14 (2.0)	85	11 (13)
Elbow	185	4 (2.1)	59	5 (8.4)
Wrist and hand ^b	539	78 (14)	128	14 (11)
All	34,137	229 (0.6)	4,524	294 (6.4)

^aSeparate statistics could not be established for ankle and toe joint replacements due to a common “99” code.

^bSeparate statistics could not be established for wrist and hand (finger and CMC I) replacements due to a common “99” code.