Patient satisfaction related outcome after total hip arthroplasty; does bearing surface play a role?

The aim of this study was to compare the functional outcome, the patient's perception of the replaced hip joint with different bearing surfaces and to study the effect of femoral head size on joint perception as well.

One hundred and ten (110) patients, who underwent primary total hip replacement with an average follow-up of 48 months (12-156 months), were assessed for their functional outcome and joint perception. The functional outcome was calculated based on Oxford hip score (OHS) and SF-36. Joint perception was categorized as to whether the replaced joint was perceived like a natural joint or artificial joint with or without restriction of movements.

There were 50 patients operated for ceramic on ceramic (CoC-hard-on-hard bearing), 60 patients for hard-on-soft bearing (Metal on Polyethelene-MoP 46, Ceramic on Polyethelene-CoP 14). Most of the patients with hard-on-hard bearings perceived their operated hip like a natural joint (p = 0.04) compared to hard-on-soft bearings. There was no significant difference in the functional outcome (OHS, SF-36) between the two bearing surface groups (p > 0.05). There were fifty patients with 28 mm size head while remaining 60 had larger heads (>32 mm). Patients with large heads felt like natural joint compared to small heads (p = 0.007).

The hard-on-hard bearing surfaces (CoC) and large femoral heads (32 mm, 36 mm) are perceived more like a natural joint. Different bearing surfaces do not affect the functional outcome after total hip replacement in a medium term follow up.