Articulating Materials Are Determinants of Survivorship of Hip Arthroplasties Performed for Nontraumatic Osteonecrosis of the Femoral Head

Abstract

A nationwide multicenter follow-up cohort study of hip-replacement arthroplasties performed for nontraumatic osteonecrosis of the femoral head (ONFH) was conducted to clarify factors associated with need for reoperation. We analyzed 7393 arthroplasties including 6284 total hip arthroplasties (THAs), 886 bipolar hemiarthroplasties (BPs), 188 total resurfacing arthroplasties, and 35 hemi-resurfacing arthroplasties (hRSs). The identified risk factors were combined systemic steroid use and excessive alcohol consumption (both ONFH-associated factors), a lateral approach, alumina BPs (aBPs), and hRSs, which were reported previously. The present study performed further analyses separately for THAs and BPs to clarify risk factors in each surgical group. A Cox proportional-hazard model identified the following risk factors: the acetabular-articulating materials of conventional polyethylene (cPE) and metal in the THAs and both ONFH-associated factors, minimum-incision surgery (MIS), and aBPs in the BPs. The risk factors were specific to each surgical group. In the ONFH patients, when performing THA, cPE and metal are not recommended as the acetabular-articulating material. When performing BP, patients with both ONFH-associated factors should be treated carefully, and the employment of MIS and use of aBP are not good strategies.

Keywords: alumina bipolar hemiarthroplasty; bipolar hemiarthroplasty; metal bipolar hemiarthroplasty; minimum-incision surgery (MIS); osteonecrosis of the femoral head (ONFH); surgical approach; survival rate; total hip arthroplasty (THA).

Figure 1

The flowchart of selecting the study groups of 6284 primary total hip arthroplasties (THAs) and 886 bipolar hemiarthroplasties (BPs) from the originally registered cohort of 7494 hip arthroplasties. tRSs: total resurfacing arthroplasties; hRSs: hemi-resurfacing arthroplasties; nBPs: a new type of BPs; oBPs: other BPs; sBPs: BPs with a smooth neck; rBPs: other BPs with a rough-surfaced neck; mBPs: BPs with a metal outer head; and aBPs: BPs with an alumina outer head. Kobayashi et al. 2024 [13].

Figure 2

The cumulative survival of total hip arthroplasties (THAs) among types of acetabular-articulating materials with need for reoperation as the endpoint. HXLPE: highly (approximately 10 Mrad) cross-linked polyethylene. MXLPE: moderately (5 to 7.5 Mrad) cross-linked polyethylene. cPE: conventional polyethylene. Survival rates for ceramic, HXLPE or MXLPH, metal, and cPE were 97%, 98%, 94%, and 93% at 10 years and 93%, 90%, 83%, and 78% at 20 years, respectively. Compared with the HXLPE or MXLPH group, the metal and cPE groups had inferior survivorship (p = 0.004 and p < 0.001, respectively), but the ceramic group did not (p = 0.657).

Figure 3

The cumulative survival of bipolar hemiarthroplasties (BPs) among osteonecrosis of the femoral head (ONFH)-associated factor groups with need for reoperation as the endpoint. Steroid: systemic steroid use. Alcohol: excessive alcohol consumption. Both: both ONFH-associated factors. None: no ONFH-associated factors. Survival rates with none, steroid, alcohol, and both were 100%, 97%, 95%, and 82% at 10 years and 94%, 90%, 93%, and 82% at 15 years, respectively. The group with both ONFH-associated factors had lower survivorship than the other groups (p ≤ 0.001). The other groups were not different from one another in survivorship (p ≥ 0.075).

Figure 4

The cumulative survival of bipolar hemiarthroplasties (BPs) between incision length groups with need for reoperation as the endpoint. Conventional: conventional incision. MIS: minimum-incision surgery. Their survival rates were 97% and 86% at 10 years, respectively. The MIS group had lower survivorship than the conventional group (p < 0.001).

Figure 5

The cumulative survival of bipolar hemiarthroplasties (BPs) between the groups of materials of the outer surface of the outer head with need for reoperation as the endpoint. mBP: BPs with a metal outer head. aBP: BPs with an alumina outer head. Their survival rates were 97% and 93% at 10 years and 89% and 74% at 20 years, respectively. The aBPs had lower survivorship than the mBPs (p = 0.008).