Homogeneity in prediction of survival probabilities for subcategories of hipprosthesis data: the Nordic Arthroplasty Register Association, 2000–2013

Figures & data

Figure 1 Flowchart for patients included in the study.

Abbreviations: NARA, Nordic Arthroplasty Register Association; OA, osteoarthritis.

Table 1 Different variables for total hip replacements

Age	Sex	Fixation	Head size	Articulation (head/cup)
20–59 years	Male	Cemented	<32 mm	M + XLP
60–74 years	Female	Uncemented	32 mm	C + XLP
Over 74 years		Hybrid	>32 mm	C + C
		Reversed hybrid		M + Poly
				C + Poly

Notes: For articulation, the first term gives the femoral head material, and the second the acetabulum bearing material.

Abbreviations: M, metal; C, ceramic; XLP, highly cross-linked polyethylene; Poly, conventional polyethylene.

Figure 2 Norwegian MSE minus NARA MSE.

Notes: The patient category in this figure is “60–74 years old, female, cemented, head size <32 mm, M + Poly”. The x-axis shows the sample size as explained in the “Statistical methods” section. The y-axis shows the difference in MSE. The red horizontal line is drawn at zero in order to visualize where the difference in MSE crosses zero, and hence shows at what sample size the Norwegian estimate becomes preferable with respect to the MSE.
Abbreviations: MSE, mean-square error; NARA, Nordic Arthroplasty Register Association; M, metal; Poly, conventional polyethylene.