Logistic regression model was used to investigate the relationship between mortality and re-operation at six months and case mix variables (age, ASA grade, fracture types, pre-fracture residence, and mobility and activity level), and management variables (days to operation, the grade of the surgeon and supervision level). Mann-Whitney test was used to compare the level of experience among trainees in the group of patients who died or required re-operation at six months.
The logistic regression model used to predict six months mortality was highly significant (X2=166.6 [24df], p<
0.0001). It showed that age, ASA grade and pre-fracture activity level were strongly associated with mortality at six months. Patients operated on by a trainee without the consultant being scrubbed were 1.8 times (p<
0.05) more likely to die at 6 months. (Odds ratio of 1.8 with 95% confidence interval of 1.15 to 2.75). Re-operation at six months could not be predicted by these factors. Regarding patients operated on by trainees, there was no significant difference in the level of experience among trainees who operated on patients who died or who required re-operation at six months compared to those who did not.
There were 159 CHS procedures and 146 IMHS procedures. 137 CHS and 123 IMHS procedures fulfilled the blood testing and transfusion criteria. Haemoglobin levels were used as an indication for blood loss attributable to surgery. The difference between the last level of haemoglobin checked preoperatively and the first post operative level performed between 12–48 hours postoperatively is calculated. Cases where blood transfusion was carried out preoperatively without further preoperative haemoglobin check were excluded, so were cases receiving intra or post operative blood transfusion prior to the defined postoperative haemoglobin check was carried out.
The surgeons’ grades were classified into three groups as: Consultants, Registrars and Senior House Officers. Levene’s test again proved the variances of haemoglobin drop within each group to be homogeneous. Hence a One-Way ANOVA test was carried out showing that the differences in haemoglobin drop were not statistically significant when comparing the three groups of surgeons to each other. This was true for both IMHS and CHS procedures. Conclusion: Patients undergoing a CHS procedure drop their haemoglobin levels by 0.64 g/dl less than those undergoing an IMHS procedure. The surgeon’s seniority does not make difference to the amount of haemoglobin level drop following either of the two procedures. We recommend the use of CHS for stable fractures and reserve the IMHS for the unstable ones due to the increased blood loss with IMHS procedures.
Indications were peri-prosthetic fractures in 9 cases (Vancouver B1 in one case, B2 in 4 cases and B3 in 4), aseptic loosening with significant bone loss in 3 (Paprosky IIIA in one case, Paprosky IIB in one and Type IV in one), osteolysis (Paprosky IV) secondary to infection in 1, non-union of peri-prosthetic fracture in 2 (Vancouver B2 and B3) and fracture around a spacer in one case. The mean HHS at 3 months post-operatively was 72 (range, 57 to 76). The median pre-operative/pre-injury University of California, Los Angeles hip rating system (UCLA) was 1. The median UCLA at longest follow-up was 3.5 (range, 1 to 4) with 10 patients having a score greater than 3. Mean time to clinical evidence of implant integration was 4 months (range, 2 to 12). No evidence of subsidence was noted. Four dislocations were seen. No dislocation was seen in the 6 patients who had a Posterior Lip Augmentation Device (PLAD™) inserted at the time of revision THA. One stem fracture occurred requiring revision surgery with a longer REEF™ implant. Two patients died in the immediate post-operative period.