With the bone impaction grafting technique, a 50/50 volume mix of morselized cancellous bone (MCB) with TCP-HA granules was used to reconstruct a critical sized acetabular defect in the goat. The biological activity of the MCB/TCP-HA mix was assessed after 15 weeks. Defects filled with 100% MCB, currently the gold standard for this technique, were used as controls. In the 100% MCB defects, a new trabecular bone structure was found in which scarce incorporated remnants of the original graft material were present. In the MCB/TCP-HA defects, MCB was also resorbed or incorporated into new bone. Deep in the MCB-TCP-HA defects, large TCP-HA granules were generally totally osseous-integrated with new bone. Superficially, more fragmented TCP-HA granules of various sizes were present in the medullar tissue or in the interface with the cement layer. Here, the crushed TCP-HA granules were generally surrounded by osteoclasts and giant cells. The soft tissue interface between the reconstruction and cement did not differ between both groups. In conclusion, from a biological point of view, this short-term follow-up study suggests that TCP-HA granules can be safely used in a mix with MCB as bone graft extender in acetabular revision surgery with the bone impaction grafting technique.