Assessing risk is a key skill for all surgeons, playing a vital role in such diverse settings informed consent, audit and surgical planning. We undertook this study to define what is an acceptable level of risk for orthopaedic surgeons undertaking lower limb arthroplasty in today's medicolegal climate.

We surveyed all consultants and trainees registered with the NZOA and asked them what change in their complication rate would cause them to consider changing their practice. We also asked them how certain they would have to be that this change was real and not simply due to chance (the so-called “cluster effect”). The specific complications we considered were DVT/PE, dislocation of total hip replacement or deep infection in lower limb arthroplasty patients. This allowed us to calculate with 95% accuracy the levels of complication surgeons would deem unacceptable.

Using Cochrane's criteria for statistically valid survey results we obtained a greater than 95% representative sample. From these responses we calculated levels of complication which would worry the “average” surgeon (median value), the “vast majority” (95%) of surgeons and a change in complication rate which would be required to satisfy “statistical significance” (i.e. the level set literature proof with p<0.05 and power of 0.8). When considering deep infection following hip or knee arthroplasty: using a baseline of 0.9% as an average published rate, the average surgeon would consider changing their practice if their rate reached 2.5% and 95% of surgeons would consider changing if their rate reached 5%. For hip dislocation the baseline was set at 2.5% with the average surgeon intervening if their rate rose to 4% and the vast majority of surgeons intervening at 10%. For fatal PE the baseline was given as 0.2% with the average surgeon auditing their practice at 0.8% and the vast majority of surgeons concerned with a rate of 2.2% or higher. No difference was found in consultant/trainee responses except in the reason given for use of thromboprophylaxis where consultants used it for prevention of fatal PE and registrars for non-fatal PE.

These results could be used both as a potential guide for trainees and consultants in audit and also in guiding the use of, for instance, thromboprophylaxis where the “number needed to treat” for low molecular weight heparin to prevent one fatal pulmonary embolus in a year would necessitate national use/guidelines.

To investigate the significance of a cluster of cases of glenohumeral chondrolysis occuring following the intra-articular injection of methylene blue to assess rotator cuff integrity during open anterior acromioplasty.

All cases of acromioplasty during the period 1999 to 2004 were reviewed to determine the incidence of chondrolysis with and without methylene blue injection.

There was a significantly higher incidence of chondrolysis following intra-articular injection of methylene blue.

The association of intra-articular methylene blue with chondrolysis has not been previously described in the literature. We conclude that methylene blue should not be used for intra-articular injection.

A retrospective audit to evaluate the effectiveness of Tranexamic Acid (TXA) in reducing blood transfusion requirements in primary total knee and hip joint replacements operated on by a single surgeon (SMD).

A survey is being sent to all Fellows of the New Zealand Orthopaedic Association who are currently in clinical practice to evaluate the strategies currently in use for reducing blood transfusion requirements in joint replacement surgery.

All primary total knee and hip joint replacements are included in this trial since February 2003. Two doses of TXA (Cyclokapron) are given at a dose of 10mg/kg intravenously. The first dose is given 10 minutes before the skin incision and the second dose 10 minutes before wound closure in the case of hip replacements and just before tourniquet release in total knee replacements. Haemostasis is secured by diathermy in the case of total knee joint replacements after tourniquet release. One deep suction drain is used.

The use of Tranexamic acid was continued until September when the numbers were collated and compared to a six-month period prior to the use of TXA. Blood loss (both measured and calculated ) and the need for transfusion were the major outcome measures. Complications related to the use of TXA were recorded.

The response rate was 89%. Various strategies to reduce blood loss were used. The mean calculated blood loss in the control group and TXA group were 1196 and 948 ml respectively. The mean measured blood loss in the control group and TXA were 595 ml and 468 ml respectively. This small number of cases – (control 8 and TXA 13) did not reach statistical significance but there was a trend in favour of reduced blood loss with the use of TXA. There was one wound haematoma in the TXA group.

A wide variety of blood conservation strategies are used by New Zealand Orthopaedic Surgeons. The use of TXA in knee joint replacements is a promising strategy.