Abstract
Background
Theoretically, improved material properties of new alumina matrix composite (AMC) material, Delta ceramics, are expected to decrease concerns associated with pure alumina ceramics and allow manufacturing thinner liners and consequent larger heads. However, limited short-term clinical results are available and mid-term results of these effects are unclear.
Questions/Purposes
(1) Does AMC material decrease the rate of ceramic fracture and noise, concerns of previous-generation ceramics, following change of material properties? (2) Does the possible use of larger heads consequent to manufacturing thinner liners decrease dislocation rate and affect inguinal pain? (3) Do any other complications associated with the use of AMC ceramics occur?
Materials and Methods
One-hundred cementless primary total hip arthroplasties (THAs) using AMC ceramic bearings were performed consecutively by single surgeon. The mean follow-up period was 5.4 years (range, 5.0 to 5.7) and average age at the time of arthroplasty was 54.7 years. Prostheses with identical design and Biolox® Delta ceramics were used in all patients. Clinical evaluation included the occurrence of inguinal pain and noise which was classified into squeaking, clicking, grinding and popping. Ceramic fracture, dislocation and any other complications associated with the use of AMC ceramics were also investigated.
Result
No ceramic fracture occurred and noise was reported in three patients (3.2%); three subjective clicking, but no squeaking. Single event of perioperative dislocation due to incompliance occurred in one hip (1.1%) and inguinal pain was reported in two hips (2.1 %); neither evidence of iliopsoas tendinitis on ultrasonography, nor association with ceramic head size (p>0.05). Liner dissociation following initial square seating was shown immediately after surgery in one hip (1.1%) and underwent revision THA.
Conclusion
Improved material properties combined with the possible use of larger-diameter head make AMC ceramics a promising alternative bearing option with reduced risk of ceramic fracture, squeaking and dislocation. In spite of these encouraging results, however, meticulous technical precautions such as square seating and proper impaction in particular, should be taken during whole process of liner insertion.
