The computed neck-shaft angle and the size of the femoral component were recorded in 100 consecutive hip resurfacings using imageless computer-navigation and compared with the angle measured before operation and with actual component implanted. The reliability of the registration was further analysed using ten cadaver femora. The mean absolute difference between the measured and navigated neck-shaft angle was 16.3° (0° to 52°). Navigation underestimated the measured neck-shaft angle in 38 patients and the correct implant size in 11. Registration of the cadaver femora tended to overestimate the correct implant size and provided a low level of repeatability in computing the neck-shaft angle.

Prudent pre-operative planning is advisable for use in conjunction with imageless navigation since misleading information may be registered intraoperatively, which could lead to inappropriate sizing and positioning of the femoral component in hip resurfacing.

Digital radiography has replaced traditional radiography in many hospitals yet little is known regarding the accuracy of this new technology in THA templating. Our study analyzed the reproducibility and reliability of computer templating in primary uncemented THA as compared to standard on-lay templating techniques with hardcopy radiographs from a digital source.

In December 2004 our hospital converted from standard hardcopy radiography to digital radiography. Patients undergoing THA had preoperative digital radiographs taken which included an AP pelvis with a 50mm magnification marker place in the groin, AP hip, and a cross-table lateral. Forty patients were selected that met our inclusion criteria to begin the templating process, including adequate placement of the magnification marker and optimal hip implant positioning on the postoperative films. Cases that did not have a marker, had significant deformity or mal-positioned implants were excluded. Hardcopies of digitised radiographs were printed and a traditional templating technique using 120% magnified on-lay transparent templates was performed (Capello, 1984). Digital templating was performed using OrthoView Software (Bono, 2004). Templating was conducted by two staff surgeons and one resident. Intra-observer and inter-observer effects were calculated using an Intraclass Correlation Coefficient (ICC).

Digital templating showed good inter-observer and intra-oberserver reliability with ICC values > 0.7. Using computer templating, the femoral stem was accurately predicted to within one size in 85% of the cases, and the acetabular cup was accurately predicted to within one size in 80% of the cases.Using on-lay templating, the femoral stem was accurately predicted to within one size in 85% of the cases, and the acetabular cup was accurately predicted to within one size in 60% of the cases.

There was a significant difference between the accuracy of acetabular cup templating between techniques, likely as a result of the ability of computer templating to adjust for magnification error. Computer templating was able to accurately predict postoperative leg-length discrepancy, abduction angle and horizontal offset. Overall, computer templating was found to be a reproducible and reliable technique for uncemented THA. Problems and lessons learned in the implementation of a digital templating system will be discussed.

Failed open reduction internal fixation (ORIF) of the proximal femur can render patients severely disabled. This study analyzed the short-term functional results and complications of total hip arthroplasty (THA) for complications of ORIF of the proximal femur. Using the Hamilton Arthroplasty Database, thirty-six patients treated with a THA for complications of ORIF of the proximal femur were compared to a matched cohort. Analysis showed that THA for complications of ORIF of the proximal femur is a successful procedure despite increased intraoperative difficulty that results in comparatively lower short-term Harris Hip Scores. No statistically significant differences in intraoperative or postoperative complications were noted.

Open reduction internal fixation (ORIF) of the proximal femur is a common, successful orthopedic procedure. However, failed ORIF of the proximal femur can render patients severely disabled. The purpose of this study is to analyze and compare the short-term functional results and complications of total hip arthroplasty (THA) for complications of ORIF of the proximal femur.

After ethics approval, the Hamilton Arthroplasty Registry, a prospective database, was used to identify thirty-seven patients treated with THA for complications of ORIF of the proximal femur. From September 1998 to the present a group consisting of sixteen males and twenty females, with a mean age of sixty-seven, were matched to a cohort of patients treated with a primary THA. Using Wilcoxon Test and Chi-Square Tests, the two groups were compared (p< 0.05).

Initially, ORIF was used to treat thirty-six patients for proximal femur fracture. The mean follow-up was 13.5 months. The experimental group had a significantly lower (p=0.035) Harris Hip Score at the one year follow-up, however both groups showed a significant improvement from preoperative scores (p=0.0001). A significant difference was noted between the two groups in estimated blood loss (p=0.01) and operative time (p=0.01). There was no significant difference in complication rate.

THA for complications of ORIF of the proximal femur is a successful procedure improving patient’s pain and functional status. This is a more complicated procedure than primary THA, at times requiring the use of a revision stem, which results in significantly lower Harris Hip Scores. Nonetheless, there appears to be no comparative increase in short-term complications.