Rapid advances in computer-assisted surgery (CAS) have lead to increasing integration of this technology into the orthopaedic training environment. The real-time feedback provided by CAS improves performance; however, it may be detrimental to learning. The primary purpose of this study is to determine if the form of feedback provided by computer-assisted technology (concurrent visual feedback) compromises the learning of surgical skills in the trainee.

Forty-five residents and senior medical students were randomised to one of three training groups and learned technical skills related to total hip replacement. The “Conventional Training” (CT) group self-determined acetabular cup position and were then corrected with traditional hand-over-hand repositioning. The “Computer Navigation” (CN) group used CAS to self-determine cup position. The “Knowledge of Results” (KR) group self-determined cup position and when satisfied used CAS for optimal repositioning. Outcomes (accuracy and precision of cup placement in abduction and anteversion, and time to position) were assessed in a pre-test, ten minute and six week retention and transfer tests. All retention and transfer tests were performed without CAS.

There were no differences between the groups at pre-test. All groups demonstrated an improvement in accuracy and precision of abduction angle and version angle determination during training (p < 0.001). The CN group demonstrated significantly better accuracy and precision in early training (p < 0.05), and better precision throughout training (p < 0.05). While the CN group demonstrated a decrease in precision during transfer testing it was not found to differ significantly from the other groups. No significant degradation in performance was observed between immediate and delayed testing for any group suggesting no negative effects of the tested training modalities on learning.

In this study the concurrent augmented feedback provided by CAS resulted in improved early performance without a compromise in learning, however, further investigation is required to ensure CAS does not compromise trainee learning. Until this issue is clarified, educators need to be aware of this potential effect.

Notching of the anterior femoral cortex during total knee arthroplasty is thought to be a possible risk factor for subsequent periprosthetic femoral fracture. Understanding the stress pattern caused by notching may help the orthopedic surgeon reduce the risk of fracture. A validated, three dimensional, finite element model of the femur using gait loads has been used to analyze the stress concentrations caused by anterior femoral cortex notching. Three factors that increase these stresses were identified. The notch depth, radius of curvature, and its proximity to the end of the femoral prosthesis influence the state of stress in the surrounding bone.

The purpose of this study was to characterize the stress concentration caused by anterior femoral notching during total knee replacement (TKR) in order to determine when a patient is at risk for a periprosthetic fracture of the femur.

We concluded that notches greater than 3 mm with sharp corners located directly at the proximal end of the femoral implant produced the highest stress concentrations and may lead to a significant risk of periprosthetic femur fracture.

One complication that can occur during TKR is notching of the anterior femoral cortex which results in a stress concentration. It is important to characterize this stress riser in order to determine when a stemmed femoral component should be used to minimize the risk of fracture.

Three factors that affected the stress concentration were identified. First, increasing the notch depth lead to significant increased stress concentrations. When the depth was greater than 3 mm, local stresses increased markedly. Second, the radius of curvature was found to be inversely related to stress concentration. As the radius decreased, the local stress increased. Third, the proximity of the notch to the prostheses affected the stress concentration. Notches that were 1 mm proximal to the implant resulted in much larger stresses than those that were 10 mm away.

A validated, three dimensional finite element model of a femur subjected to a gait loading pattern was used to characterize the stress concentration caused by anterior femoral notching. The results compared well to previous work reported in the literature.

Periprosthetic fracture management after hip arthroplasty is complicated by poor bone stock and loose femoral components. Using a prospective database, thirty-five fractures treated by proximal femoral allograft reconstruction were identified. Patients treated between 1989–2000 with minimum two- year results, were reviewed at a mean of 3.8 years. Twenty-six fractures were acute, and nine had failed previous treatment. Union of the PFA was achieved in all but five cases (83%). In twenty-eight cases (78%) no further surgery was required and patient ambulation was pain free. When conventional treatment is not possible, the use of a PFA provides encouraging results.

Periprosthetic femoral fracture treatment is complicated by comminution, bone loss, and potentially loose femoral components. Treatment can include cast-braces, internal fixation, revision arthroplasty or the use of proximal femoral allograft composites (PFA). This study reports on thirty-five fractures treated with a PFA between 1989–2000. Five patients were lost and twelve patients (33%) were deceased. Follow-up averaged 3.8 years (range 0.1–11.3) with minimum two-year results in surviving patients. Six patients had either Rheumatoid arthritis or DDH with very narrow femoral canals.

There were twenty-three acute fractures, five failures of non-operative management, four failures of ORIF and two fractured femoral stems. Fractures were classified by the Vancouver system with: B1–7%, B2–30%, B3–43% and C-20%. Prefracture functional scores revealed that 30% of patients had significant functional impairment and were awaiting revision arthroplasty. Patients had had an average of two previous surgical procedures (range 1–4).

The mean length of the PFA was 14cm and union between graft and host bone was achieved in all but five cases (83%). Resorption of the graft was seen in eight cases (27%), lucent lines in six cases (20%) and implant migration in four cases (13%). Post revision arthroplasty Harris Hip and SF-36 scores revealed substantial disability in this patient group.

Twenty-eight cases (73%) were deemed successful with patients not requiring further surgery and enjoying pain free ambulation. In fractures with unstable femoral components and inadequate bone stock or very narrow femoral canals few options are available. This technique provides encouraging results and a viable option when conventional treatment is not possible.

Notching of the anterior femoral cortex during total knee arthroplasty is thought to be a possible risk factor for subsequent periprosthetic femoral fracture. Understanding the stress pattern caused by notching may help the orthopedic surgeon reduce the risk of fracture. A validated, three dimensional, finite element model of the femur using gait loads has been used to analyze the stress concentrations caused by anterior femoral cortex notching. Three factors that increase these stresses were identified. The notch depth, radius of curvature, and its proximity to the end of the femoral prosthesis influence the state of stress in the surrounding bone.

The purpose of this study was to characterize the stress concentration caused by anterior femoral notching during total knee replacement (TKR) in order to determine when a patient is at risk for a periprosthetic fracture of the femur.

We concluded that notches greater than 3 mm with sharp corners located directly at the proximal end of the femoral implant produced the highest stress concentrations and may lead to a significant risk of periprosthetic femur fracture.

One complication that can occur during TKR is notching of the anterior femoral cortex which results in a stress concentration. It is important to characterize this stress riser in order to determine when a stemmed femoral component should be used to minimize the risk of fracture.

Three factors that affected the stress concentration were identified. First, increasing the notch depth lead to significant increased stress concentrations. When the depth was greater than 3 mm, local stresses increased markedly. Second, the radius of curvature was found to be inversely related to stress concentration. As the radius decreased, the local stress increased. Third, the proximity of the notch to the prostheses affected the stress concentration. Notches that were 1 mm proximal to the implant resulted in much larger stresses than those that were 10 mm away.

A validated, three dimensional finite element model of a femur subjected to a gait loading pattern was used to characterize the stress concentration caused by anterior femoral notching. The results compared well to previous work reported in the literature.

Periprosthetic fracture management after hip arthroplasty is complicated by poor bone stock and loose femoral components. Using a prospective database, thirty-five fractures treated by proximal femoral allograft reconstruction were identified. Patients treated between 1989–2000 with minimum two- year results, were reviewed at a mean of 3.8 years. Twenty-six fractures were acute, and nine had failed previous treatment. Union of the PFA was achieved in all but five cases (83%). In twenty-eight cases (78%) no further surgery was required and patient ambulation was pain free. When conventional treatment is not possible, the use of a PFA provides encouraging results.

Periprosthetic femoral fracture treatment is complicated by comminution, bone loss, and potentially loose femoral components. Treatment can include cast-braces, internal fixation, revision arthroplasty or the use of proximal femoral allograft composites (PFA). This study reports on thirty-five fractures treated with a PFA between 1989–2000. Five patients were lost and twelve patients (33%) were deceased. Follow-up averaged 3.8 years (range 0.1–11.3) with minimum two-year results in surviving patients. Six patients had either Rheumatoid arthritis or DDH with very narrow femoral canals.

There were twenty-three acute fractures, five failures of non-operative management, four failures of ORIF and two fractured femoral stems. Fractures were classified by the Vancouver system with: B1–7%, B2–30%, B3–43% and C-20%. Prefracture functional scores revealed that 30% of patients had significant functional impairment and were awaiting revision arthroplasty. Patients had had an average of two previous surgical procedures (range 1–4).

The mean length of the PFA was 14cm and union between graft and host bone was achieved in all but five cases (83%). Resorption of the graft was seen in eight cases (27%), lucent lines in six cases (20%) and implant migration in four cases (13%). Post revision arthroplasty Harris Hip and SF-36 scores revealed substantial disability in this patient group.

Twenty-eight cases (73%) were deemed successful with patients not requiring further surgery and enjoying pain free ambulation. In fractures with unstable femoral components and inadequate bone stock or very narrow femoral canals few options are available. This technique provides encouraging results and a viable option when conventional treatment is not possible.

Purpose: Many surgeons are now performing hip arthroplasty using a minimally invasive technique with the aim of reducing muscle damage and improving rehabilitation. We compared the learning curve of two MIS THA approaches: the two-incision mini and a modified Watson-Jones (G3) approach.

Methods: A retrospective review of 47 consecutive patients who underwent a THA using an MIS approach was conducted. All patients received an uncemented acetabular cup (Trilogy–Zimmer) fixed with 1 or 2 screws, and an uncemented femoral stem (ML taper, fiber metal taper, fully porous coated–Zimmer). Note was made of BMI, surgical time, incision length, blood loss, component positioning, hospital stay and perioperative complications.

Results: Twenty-one patients received a G3 and 26 received a 2 incision mini approach. The average BMI was 29.7 and 26.1 respectively. Average acetabular inclination was 37 for the G3 and 42 for the 2-incision mini. On average, the femoral component was positioned in neutral in the coronal plane for both approaches. Average surgical time was 121minutes for the G3 and 166 minutes for the 2-incision which also includes fluoros-copy time. Hospital stay averaged 5.4 and 6.8 days respectively. The skin incision averaged 8.9 cm for G3 a total of 9.8cm for 2-incision. Perioperative complications for the G3 included 1 lateral femoral cutaneous nerve palsy, 1 DVT, 1 PE and 1undisplaced intraoperative acetabular fracture. Complications for the 2-incision mini included 5 intraoperative fractures, 7 nerve injuries, 1 wound infection, 1 infection requiring revision and 1 PE.

Conclusions: The G3 minimally invasive approach for THA has advantages over the 2-incision mini: shorter operative time, no need for fluoroscopy, fewer days in hospital, shorter total incision length and lower complication rate. The G3 approach also offers the opportunity to bail out to a traditional approach, by extending the incision, should this be necessary.

Introduction: Distal femoral varus osteotomy (DFVO) has been advocated as the treatment of choice for lateral compartment osteoarthritis associated with a valgus knee in the young population in order to delay the need for total knee arthroplasty (TKA). The aim of this study was to evaluate the long-term results of DFVO for the valgus osteoarthritic knee.

Methods: A retrospective analysis was performed on 38consecutive patients (40 knees) who underwent a DFVO between 1984 and 2001. Two patients (2 knees) were lost to follow-up. Mean follow up was 123 months (range 39 to 245 months). Peri-operative documentation was evaluated for etiology, pre-operative functional and subjective impairment, intra-operative technical difficulties or complications, early and late post-operative complications and post-operative functional and subjective outcomes.

Results: At the time of the most recent follow-up, 24 knees had good or excellent result, 3 knees had a fair result and 3 had poor results. The remaining 8 knees were converted to a total knee arthroplasty. The mean Knee Society objective score improved from 18 (range, 0–74) to 87.2 (range, 50–100) and the mean Knee Society function score improved from 54 (range, 0–100) to 85.6 (range, 40–100). The ten-year survival rate of DFVO was 82% (95% confidence interval, 75%–89%) and the fifteen-year survival rate was 45% (95% confidence interval, 33%–57%).

Discussion: With proper patient selection, DFVO is a reliable procedure for the treatment of the valgus osteoarthritic knee. This procedure delays the need for further surgical procedures, such as TKA, with good results.

Introduction: The Evan’s staple is an intramedullary device. It has two 20 cm tines connected by a horizontal bar with a hole mid-apex to facilitate insertion over a K-wire and enhance fixation to the humerus by means of a tension band.

Aim: To perform a retrospective review of the results of using the Evan’s staple as a means of fixation for displaced proximal humeral fractures.

Method: Between 1989 and 1997 at the Toronto East General Hospital, 56 patients with displaced proximal humeral fractures were treated with an Evans’ staple. This included 14 three-part and four four-part fractures and six fracture-dislocations. The age range at the time of operation was 18–94 years. The average duration of follow-up was 48.6 months, the range being 11–99 months. The study consisted of patient chart review, radiological review and use of the DASH (Disabilities of the Arm, Shoulder and Hand) questionnaire.

Results: Complete radiological data were available for 26 patients and these showed a 100% union rate. The majority (77%) healed in neutral, the remainder in varying degrees of varus. Twenty-one patients returned the DASH questionnaire, with an average functional score of 37.8 (0= no disability, 100= severe disability). The complications included eight cases of impingement that required staple removal and one fracture distal to a staple caused by a subsequent fall.

Conclusion: The Evan’s staple is a viable means of fixation for displaced proximal humeral fractures.

Fresh osteochondral allografts were used to repair post-traumatic osteoarticular defects in 92 knees. At the time of grafting, varus or valgus deformities were corrected by upper tibial or supracondylar femoral osteotomies. A survivorship analysis was performed in which failure was defined as the need for a revision operation or the persistence of the pre-operative symptoms. There was a 75% success rate at five years, 64% at ten years and 63% at 14 years. The failure rate was higher for bipolar grafts than for unipolar and the results in patients over the age of 60 years were poor. The outcome did not depend on the sex of the patient and the results of allografts in the medial and lateral compartments of the knee were similar. Careful patient selection, correction of joint malalignment by osteotomy, and rigid fixation of the graft are all mandatory requirements for success. We recommend this method for the treatment of post-traumatic osteochondral defects in the knees of relatively young and active patients.