Introduction: For patients in employment a fast rehabilitation is important. The reduced risk of dislocation when using a large-head metal-on-metal articulation theoretically offers a faster rehabilitation than a THA with a 28 mm articulation due to no restrictions. The larger surgical incision in the resurfacing patient may impair the early rehabilitation.

We aimed to investigate early differences in rehabilitation parameters amongst the different groups.

Methods:We randomized to resurfacing (n=20), standard 28 mm THA (n=19) and large head MoM THA (n=12). We recorded operation time, blood loss, incision length, length of stay and length of sick-absence. Clinical scores: WOMAC, HHS, UCLA activity and steps were recorded preoperatively, at 8 weeks and 6 months, with additional WOMAC at 3 and 6 weeks.

Results: Results reported for resurfacing, 28 mm and large head THA, respectively. The incision measured 23.4 ( 2.9),  14.3 ( 3.6) and 14.1 ( 1.1) cm. The blood loss amounted to 536.7 (474.9), 426.5 (175.1) and 816.7 (347.9) mL. Both differed statistically, but the length of stay did not. The WOMAC activity and stiffness subscale were significant better in the large head THA at 6 months (7.3 (8.4), 12.8 (11.1) and 3.4 (4.0) mm and 12.2 (21.7) 21.6 (22.2) 5.0 (6.3) mm). Pain scores, UCLA activity, HHS, step rate or time before returning to work did not differ.

Conclusion: The present study showed an increase in early activity level in patients with large head THA and a tendency for resurfacing compared to a standard THA without increasing pain scores