Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMD.

119 patients were randomized to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. Dual energy x-ray absorptiometry scans (Lunar iDXA, GE Healthcare, Madison, WI) assessed BMD across the seven Gruen zones pre-operatively, and post-operatively at 6-weeks, 1-year, and 2-years comparing the unoperated contralateral femur as a control.

BMD increased in zones one (2.5%), two (17.1%), three (13.0%), five (10%) and six (17.9%) for all stems. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual taper wedge and anatomic stems (p = 0.019). The dual taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7) whilst the anatomic and triple taper stem declined in this region, however this was not statistically significant (p = 0.059). BMD decreased on average by 2.1% in the mid-diaphysis region, distal to the stem tip (zone 4) for all implants. All stems performed equivalently at final follow-up in all patient reported outcome measures.

Implant design was shown to impact BMD changes. All stems preserved bone at the metaphyseal level in early follow-up, which theoretically indicates favorable implant fixation. There was no significant stress shielding observed, however longer follow-up is required to elucidate the impact of this finding on implant survivorship.

PFFs are an increasing burden presenting to the acute trauma services. The purpose of this study is to show that cemented revision for Vancouver B2/B3 PFFs is a safe option in the geriatric population, allows early pain-free weight bearing and comparable to a control-group of uncemented stems with regard to return to theatre and revision surgery.

A retrospective review was conducted of all PFFs treated in a Level 1 trauma centre from 2015-2020. Follow up x-rays and clinical course through electronic chart was reviewed for 78 cemented revisions and 49 uncemented revisions for PFF. Primary endpoints were all cause revision and return to theatre for any reason. Secondary endpoints recorded mobility status and all-cause mortality.

In the cemented group there were 73 Vancouver B2, 5 Vancouver B3 PFF; the mean age was 79.7 years and mean radiological follow-up of 11.9 months. In the cementless group there were 32 Vancouver B2 and 17 Vancouver B3 PFFs; with all 49 patients undergoing distally bearing uncemented revision, the mean age was 72.7 years and mean radiological follow-up of 21.3 months.

Patients treated with a cemented prosthesis had significantly higher ASA score (2.94 -v- 2.43, p<0.001). The primary endpoints showed that there was no significant difference in all cause revision 3/78 and 5/49 p=0.077, or return to theatre 13/78 -v- 12/49 p=0.142.

Secondary endpoints revealed no significant difference in in-hospital mortality. The cementless group were more likely to be mobilising without any aid at latest follow-up 35/49 -v- 24/78 p<0.001.

The use of cemented revision femoral component in the setting of PFFs is one option in the algorithm for management of unstable PFFs according to the Vancouver classification. Evidence from this case-control study, shows that the all-cause revision and return to theatre for any cause was comparable in both groups.

Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMDMethods: 119 patients were randomised to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. All surgeries were performed via the posterior approach with mobilization on the day of surgery. Dual energy x-ray absorptiometry scans (Lunar iDXA, GE Healthcare, Madison, WI) assessed BMD across the seven Gruen zones pre-operatively, and post-operatively at 6-weeks, 1-year, and 2-years and compared to the unoperated contralateral femur as a control. Patient reported outcome measures of pain, function and health were also included at these corresponding follow-ups.

BMD increased in zones one (2.5%), two (17.1%), three (13.0%), five (10%) and six (17.9%) for all stems. Greater preservation of BMD was measured on the lateral cortex (zone 2) for both the dual taper wedge and anatomic stems (p = 0.019). The dual taper wedge stem also demonstrated preservation of BMD in the medial calcar (zone 7) whilst the anatomic and triple taper stem declined in this region, however this was not statistically significant (p = 0.059). BMD decreased on average by 2.1% inthe mid-diaphysis region, distal to the stem tip (zone 4) for all implants. All stems performed equivalently at final follow-up in all patient reported outcome measures.

This study demonstrated maintenance of femoral BMD in three different cementless femoral stem designs, with all achieving excellent improvements in patient reported outcomes. There was no significant stress shielding observed, however longer follow-up is required to elucidate the impact of this finding on implant survivorship.

Introduction: This study aimed to determine the accuracy of computer navigation in simulated fixation of femoral neck and supracondylar femoral fractures using different sizes of guidewires and drills from commercially available cannulated screw systems.

Methods: Simulated fracture fixation was performed with 2.5mm, 2.8mm and 3.2mm threaded guidewires and 3.2mm and 5mm drill bits using 20 4th generation synthetic femurs. The drill or guide wire was inserted in the synthetic femurs, using fluoroscopy based computer navigation (24 drills/guidewires in each group). Pre and postoperative fluoroscopy images were acquired with the C-arm and synthetic bone in the same orientations. Virtual and real wire/drill positions were compared, and errors calculated for each diameter of drill/guidewire (sum AP + Lateral error (mm)). Errors were compared using a general linear model with Tukey adjustment for multiple comparisons. Statistical significance at a two-tailed p-value < 0.05.

Results: The mean error for the 5.0mm drill (3.20mm) was significantly less than all the threaded wires (p< 0.05). The mean error for the 3.2mm drill (5.68mm) was significantly less than the 2.5mm guidewire (9.27mm) p< 0.05, and less than the 2.8mm (8.19mm) and 3.2mm (7.14mm) threaded wires.

Discussion: For cannulated screws, the 3.2mm drill was the most accurate size tested. The most accurate drill, 5mm, would allow solid screw insertion. However, its large size may preclude screw repositioning, and unlike a cannulated screw, would not maintain fracture position whilst the screw was being inserted.

Introduction: This study compared the accuracy of reduction of intra-medullary nailed femoral shaft fractures, comparing conventional and computer navigation techniques.

Methods: Twenty femoral shaft fractures were created in human cadavers, with segmental defects ranging from 9–53mm in length. All fractures were fixed with antegrade 9mm diameter femoral nails on a radiolucent operating table. Five fractures (control) were fixed with conventional techniques. Fifteen fractures (study) were fixed with computer navigation, using fluoroscopic images of the normal femur to correct for length and rotation. The surgeon was blinded to defect size. Two landmark protocols were used in the study group referencing the piriform fossa (Group A, n=10) or proximal shaft axis (Group B, n=5). Postoperative CT scans, blindly reported by a musculoskeletal radiologist, were used to compare femoral length and rotation with the normal leg.

Results were analysed using ANOVA with 95% Confidence Intervals.

Results: The control and study groups were not statistically different with respect to age of cadaver or size of femoral defect. Results: The mean leg length discrepancy in the study groups were significantly less (3.6mm (95% CI 1.072 – 6.128) and 4.2mm (95% CI 0.63–7.75), compared with 9.8mm (95% CI 6.225 – 13.37) in the control group (p< 0.023). The mean torsional deformities in the study groups were 8.7 degrees (95% CI 4.282 – 13.12) and 5.6 degrees (95% CI -0.65 – 11.85), compared with 9 degrees (95% CI 2.752 – 15.25) in the control group (p=0.650). Within the navigated study group, length discrepancy was similar in subgroups 1 (3.6mm) and 2 (4.2mm). Torsion appeared more accurate in group 2 (5.6 degrees) than group 1 (8.7 degrees), although this was not statistically significant.

Discussion: Computer navigation significantly improves the accuracy of femoral shaft fracture fixation with regard to length. With further modifications to improve reduction of rotational deformity, it may be a useful technique in the treatment of femoral fractures.

This study compared the accuracy of reduction of intra-medullary nailed femoral shaft fractures, comparing conventional and computer navigation techniques.

Twenty femoral shaft fractures were created in human cadavers, with segmental defects ranging from 9–53mm in length. All fractures were fixed with antegrade 9mm diameter femoral nails on a radiolucent operating table. Five fractures (control) were fixed with conventional techniques. Fifteen fractures (study) were fixed with computer navigation, using fluoroscopic images of the normal femur to correct for length and rotation. The surgeon was blinded to defect size. Two landmark protocols were used in the study group referencing the piriform fossa (n=10) or proximal shaft axis (n=5). Postoperative CT scans, blindly reported by a musculoskeletal radiologist, were used to compare femoral length and rotation with the normal leg. Results were analysed using the Wilcoxon two-sample test.

The mean leg length discrepancy in the study group was 3.8mm (range 1–9), compared with 9.8mm(range 0–17) in the control group (p=0.076). The mean torsional deformity in the study group was 7.7 degrees (range 20–2) compared with 9 degrees (range 0–22) in the control group (p=0.86). Within the navigated study group, length discrepancy was similar in subgroups A (3.6mm) and B (4.2mm). Torsion appeared more accurate in group B (5.6 degrees) than group A (8.7 degrees), although not significantly.

Computer navigation appears to improve leg length discrepancy following femoral nailing. Technique modification during the study improved rotational accuracy, and with further improvement, will make this technique applicable to femoral fracture fixation.

The aim was to review patients that had single stage bilateral total hip joint replacements (SSBTHJR) of two surgeons in the Wellington area, to assess symptomatic relief and overall quality of life before and after surgery. To also review xrays of this population to assess acetabular component orientation.

Fifty patients from two hospitals, with minimum follow up of two years, who had SSBTHJR, were reviewed for duration of stay, time to mobilisation, and complications (eg. wound infections, venous thrombus and embolism (VTE), gastrointestinal ileus, and cardiac events). Patient opinions on hip joint function (Oxford Hip Score) and overall quality of life (EQ-5D Score) were performed (37/50 patients could participate). Patient’s postoperative radiographs were analysed with Polyware Auto Version 6.00 to measure acetabular cup orientation for both sides.

Oxford Hip Score mean was 20.5 (range 12 – 56), compared to the national mean 19.3. The median score was 14. Most patients (65%) had no symptoms of pain, difficulty in mobilising, or performing activities of daily living (ADL). 19% of patients had mild to moderate symptoms/difficulty, and 16% had significant pain/difficulty On average, using a visual analogue scale, patients felt their health was 42% better after having their surgery. Complication rates were minimal, and were primarily superficial wound infections. Hip acetabular cup positioning analysis was performed (statistical analysis pending).

Patients undergoing SSBTHJR have comparable results for Oxford Hip Scores compared to unilateral THJR patients, improved lifestyle, but not increased complications.

Introduction: Ankle fractures are the third most common fracture presenting at public hospitals in New Zealand. There have been few outcome studies following treatment of ankle fractures.

Aim: To identify the relationship between three types of ankle fractures and the functional and quality of life outcomes for patients two years after the injuries.

Methods: Seventy-four patients seen at Wellington Hospital with ankle fractures during 1998 were contacted for the study. Patients had been treated by open reduction and internal fixation, or by the application of a plaster cast with manipulation of the fracture being performed where necessary. Each patient completed an ankle specific Olerud and Molander questionnaire and an EQ5D Quality of Life Outcome measure. All x-rays were analysed and the fractures were classified using the Weber classification.

Results: There were 22 males and 52 females, 11% had Weber type A fractures, 67% had Weber type B, 18% Weber type C and 4% an isolated posterior malleolar fracture. Fifty-one patients underwent surgery. Patients who sustained Weber type A fractures generally recorded good to excellent OMA scores, while those with Weber Band C fractures produced significantly poor results. An analysis of the ankle visual analogue score versus the method of treatment showed that patients who underwent surgery judged their ankle to be less functional than the patients who had non-surgical interventions. The mechanism of injury also correlated with the end result, patients who had injured their ankles during sporting activities scored lower scores than those who had injured their ankles in simple falls. Patients requiring removal of an internal fixation device had a lower OMA score when compared with those who retained their fixation devices in situ.

Conclusions: This long-term out come study indicated that there was significant dysfunction following ankle fractures, with a surprising level of disability following Weber B and C fractures. The results of this study do not indicate better results in those patients who underwent surgery.