For the MDIs, a small longitudinal skin incision was made just distal to the tibia/femur joint. The tibia/femur head was exposed subperiosteally, and an osteotomy was performed with the pilot drill under copious irrigation with saline solution, transposing the cortical bone to the depth of 0.5 mm. The implants were aseptically transferred to the bone site and manually rotated clockwise while exerting downwards pressure to start the self-tapping process. When bony resistance was encountered, the winged thumb wrench was used for driving the implant deeper into the bone, if necessary.

Ankylos® implants were inserted in the other tibia/femur head of the animals according to the manufacturer’s protocol as follows: After mobilizing the subperiosteal flap and using a 3-mm center punch to register a guiding point for the osteotomy, a twist drill, depth drill series and a conical reamer were used sequentially to complete the osteotomy and to develop a conical shape for accomodation of the implant’s body. A counterclockwise rotation was used to compress the bone in case of soft bone. The tap or thread cutter was used to create the threads in dense bones. Following, the implant assembly was aseptically transferred to the osteotomy site, and the implant placement was started manually and finalized using a hand ratchet. If excessive force was experienced, the osteotomy was irrigated, and the depth was checked by retapping.

Resonance frequency assessment was performed thrice, just after the insertion of the implants, using the Osstell ISQ™ device. In brief, customized SmartPegs were stabilized onto the head of the 3M™ESPE™ MDIs and Osstell company’s specific SmartPeg™ devices were screwed into Ankylos® implants, taking care to ensure that no significant torquing force was applied to the implants, and the RFA was carried out. These procedures were repeated for post-euthanasia RFA.

The rabbits were given a dose of cephalexin 12 mg/kg 0.5 mL IV once intraoperatively and a postoperative analgesic, i.e., carprofen 2–4 mg/kg SC every 8 h for 3 days, according to McGill’s SOP. The animals had a free access to water and food, and routine daily care followed as per McGill’s SOP#524.01. The sutures were removed after 7–10 days, and the animals were euthanized at 6 weeks postoperatively. It has been shown by various authors that this period is adequate to develop a “rigid osseous interface” in rabbits [30]. An overdose of pentobarbital sodium 1 mL/kg intravenously was used for this purpose [48].