**4. Conclusions**

Surgeries of joint arthroplasties are among the most successful operations in the entirety of medicine. Since the early 1960s, hip replacement surgical techniques and technology improvements have increased the effectiveness of this procedure. Because the range of motion grows and the jump distance to subluxation and/or dislocation becomes greater, there is significant interest in adopting larger-diameter heads. If we switch to hard-on-hard couplings, we may utilize heads larger than 32 mm: AMC-on-AMC bearing surfaces are appealing alternative bearing surfaces that remove or substantially minimize the issues associated with PE wear debris. A new low-frictional torque arthroplasty theory can be established owing to their sliding characteristics and better wettability than PE: with ceramic components (inlay and head), due to a lower coefficient of friction, it is possible to enlarge the femoral head diameter without increasing the frictional torque and to grant a wider range of movement that will last because ceramic–ceramic bearings avoid wear. When a PE liner develops wear, the center of rotation migrates centrally and/or cranially, and the deeper the head, the more restricted the range of motion becomes; in fact, late dislocation can be the first clinical sign of wear, with a cumulative risk of firsttime dislocation that is 2-fold and 3-fold at 10 and 20 years, respectively, when compared to the 1-year follow-up [14,30–43]. Breakage of ceramic components is a ceramic-specific issue; we have not seen any fractures in our series.

This may be explained by the better manufacturing process, the exact contact surface geometry, including appropriate clearance, and the greater resistance to fracture when employing heads with a diameter of 32 mm or bigger. According to Santavirta S [44], the component fracture risk for currently available ceramic goods is essentially non-existent, as demonstrated in clinical trials at 4 and 5 years, even with a 28 mm head [45,46]. If the diameter is even bigger, more benefits in terms of both strength and function are obtained: in the first three months following surgery, the rate of dislocation was 0.88% for 36 mm heads and 4.64% for 28 mm heads [47].

Around the world, total hip arthroplasty is becoming more prevalent in younger patients [48]. Ceramic bearing implants for THA surfaces are now extensively utilized across the world to reduce wear debris and aseptic loosening. When utilizing ceramic components, the surgical technique must be precise [49].

Our findings show that AMC-on-AMC couplings provide outstanding outcomes in THA conducted in high-demand patients, with no material-related side effects, no ceramic fracture and no mechanical loosening of implant components. The danger of dislocation should be reduced if the head has a diameter of 32 mm or more. Overall, we believe AMC-on-AMC to be the bearing of choice for younger and more active patients due to its dependability and longevity.

**Author Contributions:** Writing—original draft, G.S., A.S., A.V., F.S., M.B. and B.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

