[1] Univ Cape Town, OrthoBallist Res Ctr, Dept Orthopaed Surg, Cape Town, South Africa
[2] Univ Witwatersrand, Charlotte Maxeke Acad Hosp, Dept Orthopaed Surg, Johannesburg, South Africa
[3] Univ Hosp Bern, Dept Orthopaed Surg & Traumatol, Inselspital, Bern, Switzerland