Response to comment on Gagala et al.: Clinical and radiological outcomes of treatment of avascular necrosis of the femoral head using autologous osteochondral transfer (mosaicplasty). Preliminary report.

Dear Dr. Siddhartha Sharma,

Thank you very much in your interest in our article [1]. We would like to answer your questions point by point as below.

The OATS/allograft was performed as a salvage procedure in patients with ARCO III and IV who refused total hip replacement and asked for a joint preserving operation. The use of OATS in osteonecrosis of the femoral head (ONFH) was approved by the local ethical committee. A written consent was obtained from every single patient.

MRI is a better tool to observe ONFH progression and graft incorporation than X-rays, but unfortunately the Polish National Health Fund covers the cost of MRI examination performed as a diagnostic but not as a scientific method. Follow-up examinations from recently published papers presenting novel ONFH treatment also use only X-ray results [2].

The exact location of drill bits for OATS was planned upon preoperative MRI examination. We did not have any problems either in necrotic segment identification during the procedure or in inspection of complete removal.

Bone defects were packed with morsellised allogenic bone; no osteochondrall allografts were implanted in the OATS/allograft group.

The indication for subtrochanteric osteotomy in one case was excessive femoral neck anteversion.

Up to 2013, seven papers, mainly case reports and case series, were published presenting outcomes of 31 hips in which OATS had been performed for different indications [3-9]. The aim of our preliminary report was to present the outcomes of OATS in 21 patients with ONFH and to share with the orthopaedic community our experiences of this novel technique.

As mentioned above our paper is a preliminary report so we think there is no need for a control group to confirm our conclusions.