The influence of tricalcium aluminate (3CaO·Al2O3) phase doping on in vitro biocompatibility and bioactivity of calcium aluminate (CaO·Al2O3) based bone cement has been investigated. It is demonstrated that the presence of approximately 25% tricalcium aluminate in the bone cement remarkably improves the bioactivity, yet still retains desirable mechanical strength and biocompatibility. An intermediary compound layer such as Ca3Al2(OH)12 was formed on the surface of the doped sample onto which hydroxyapatite (HAp) began to form soon, after only 2 days of immersion in a simulated body fluid solution. This is about seven-fold acceleration in the HAp formation over undoped calcium aluminate cement on which it took approximately15 days to nucleate the HAp phase. The depth of the HAp-containing layer after60 days of soaking was as much as 85 μm, about an order of magnitude more than the undoped calcium aluminate cement. The dramatically accelerated nucleation and growth of hydroxyapatite caused by the presence of tricalcium aluminate is attributed to the occurrence of intermediate layer materials such as Ca3Al2(OH)12, which most likely acts as the nuclei for HAp formation. This doped bone cement can be useful for injectable orthopedic applications, as the setting time for hardening has also been significantly reduced (by a factor of at least 4) to a practical regime of tens of minutes.

Fourteen patients who underwent Charnley or Howse total hip replacement using CMW bone cement were studied. Mean values of C4 and C3 determined before the induction of anaesthesia and insertion of bone cement and also after this procedure showed no significant difference and were within the normal range. Furthermore, no evidence of C3 breakdown products was found. It was therefore concluded that neither the general anaesthetic technique nor the insertion of bone cement activated the classical or alternative complement pathways and such a mechanism was not responsible for the hypotension which occurred shortly after the insertion of bone cement in 10 cases studied.

A report is made of respiratory complications which occurred following the insertion of Palacos bone cement during Howse total hip replacement under spinal anaesthesia in a 78-year-old female patient. Persistent cough and tachypnoea developed 30 s after the insertion of bone cement into the acetabulum and femur and persisted for 2–3 min producing considerable passive movement of the pelvis and femur. The probable cause, disadvantages and prevention of these complications are discussed.