Table 4.

Summary of studies in which development of OA was studied on the contralateral hip after arthroplasty

Study	Journal	Year	Number	Findings
Ritter et al. [18]	J Arthroplasty	1996	1116 patients (664 with normal hips)	Contralateral OA 79% at 10 years with 54% with THA; in normal hips 37% OA and 8% with THA
Goker et al. [10]	Arthritis Rheum	2000	99 patients	Eighty-five percent of patients maintained a slow decline in joint space width (< 0.2 mm/year), and 15% had an accelerated decline in joint space width (> 0.2 mm/year); 21% underwent contralateral THA
Vossinakis et al. [20]	Skeletal Radiol	2008	95 patients (56 with idiopathic OA)	Idiopathic OA of one hip increases risk of contralateral OA; prediction difficult only from radiographic measurements; weightbearing surface best predictor
Şahin et al. [19]	J Int Med Res	2011	44 subjects with idiopathic OA and 40 control subjects	No difference in center-edge angle but femoroacetabular impingement features more prevalent in contralateral hip of patients with idiopathic OA
Current study	CORR ®	2016	367 patients	Forty-one percent of patients progress to Charnley Class B disease, of which 19% undergo hip arthroplasty within 10 years; joint space width, center-edge angle, head-to-neck ratio, and osteophytes predicted development of OA; center-edge angle less than 25° counteracts the effect of a low head-to-neck ratio

OA = osteoarthritis.