Bilateral sequential total knee replacement with a Zimmer NexGen prosthesis (Zimmer, Warsaw, Indiana) was carried out in 30 patients. One knee was replaced using a robotic-assisted implantation (ROBOT side) and the other conventionally manual implantation (CON side). There were 30 women with a mean age of 67.8 years (50 to 80).

Pre-operative and post-operative scores were obtained for all patients using the Knee Society (KSS) and The Hospital for Special Surgery (HSS) systems. Full-length standing anteroposterior radiographs, including the femoral head and ankle, and lateral and skyline patellar views were taken pre- and post-operatively and were assessed for the mechanical axis and the position of the components. The mean follow-up was 2.3 years (2 to 3).

The operating and tourniquet times were longer in the ROBOT side (p < 0.001). There were no significant pre- or post-operative differences between the knee scores of the two groups (p = 0.288 and p = 0.429, respectively). Mean mechanical axes were not significantly different in the two groups (p = 0.815). However, there were more outliers in the CON side (8) than in the ROBOT side (1) (p = 0.013). In the coronal alignment of the femoral component, the CON side (8) had more outliers than the ROBOT side (1) (p = 0.013) and the CON side (3) also had more outliers than the ROBOT side (0) in the sagittal alignment of the femoral component (p = 0.043). In terms of outliers for coronal and sagittal tibial alignment, the CON side (1 and 4) had more outliers than the ROBOT side (0 and 2).

In this series robotic-assisted total knee replacement resulted in more accurate orientation and alignment of the components than that achieved by conventional total knee replacement.

Introduction: ROM after TKA can be influenced by multi-factors such as preoperative range of motion, body habitus, implant design, intraoperative surgical technique, and postoperative rehabilitation. Recently many implant manufacturers have made modifications to traditional total knee designs to improved maximal knee flexion and range of motion. Some posterior cruciate ligament (PCL) stabilized total knee prostheses that incorporate design features intended to improve knee kinematics in high flexion were introduced and the use of these prostheses has attracted attention. Recently in the cruciate retaining (CR) prosthesis, high-flexion knee (CR-Flex) and gender-specified prosthesis were designed to allow a greater and safer flexion after TKA. The aim of this study was to evaluate the effect of cruciate retaining typed different femoral component design on knee range of motion using a computerized navigation system.

Materials & method: 30 patients who underwent primary TKA because of primary osteoarthritis were included. EM navigation system was used in all cases. After tibia and femoral cutting using standard CR cutting block, standard fixed bearing CR knee (NexGen CR, Zimmer, Warsaw, IN) trial was inserted. If surgeon is satisfactory with alignment, stability and ligament balancing, the maximal knee extension and flexion was recorded using gravity by navigation system. Then, high-flexion fixed bearing CR knees(NexGen CR-Flex and Gender solution NexGen CR-Flex knee, Zimmer, Warsaw, IN) trial was inserted after additional posterior cutting. The maximal knee extension and flexion was evaluated exactly same way.

Results: Preoperative mean varus deformity was 10.52°. The mean flexion contracture was 7.52±6.81° and further flexion 129.9±7.94°. The average intraoperative maximal flexion of NexGen CR was 133.5±5.35° (125–146°) and that of hyper-flexion design were 135.5±5.77°(125–147°) in Nexgen CR-Flex and 136.1±5.76°(126–146°) in Gender knee. All knees showed greater than 125° of flexion regardless of the implant design. All knees can achieve physiologic leg alignment and nearly full extension of the knee after operation.

Conclusion: Hyper flexion designs showed subtle increase in mean maximal flexion and overall range of motion of the knee compared with the standard design, when it measured using navigation system intraoperatively. But clinically, it is not certain that these differences can lead to significant improvement of range of motion.

The study is to evaluate mid-term follow-up clinical results and navigation prediction of the first 106 TKAs, which was performed based on the soft tissue balancing technique using the OrthoPilot navigation system (B.Braun Aesculap, Tuttlingen, Germany).

All the 106 cases were diagnosed as osteoarthritis with varus deformity. After anatomical and kinematic registration, the mechanical axis was restored to neutral (±2°) at full extension with step by step meticulous medial soft tissue release and osteophyte removal. Proximal tibial bone cutting was performed under real-time navigation system control. Flexion and extension gaps were measured at full extension and at 90° of flexion using a tensioning device (V-STAT tensor, Zimmer) and a special torque wrench set at 50lb/inch before femoral bone cutting. The flexion and extension gap was evaluated and it’s difference was classified into 3 kinds; balanced, tight flexion gap and tight extension gap. Sixty-one (57.5%) knees were classified as having a ‘balanced gap’ (meaning that flexion and extension gaps were within 2 mm), 20 (18.9%) knees as having a ‘tight flexion gap’ (an extension gap at least 3mm more that the corresponding flexion gap), and 25 (23.6%) knees as having a ‘tight extension gap’ (a flexion gap at least 3mm more that the corresponding extension gap). Depending extension/flexion, and medial/lateral gap difference, the level of distal femoral cut and the rotation of femoral component was determined. Following the final bone cuts and completion of soft tissue release, assessment of the flexion and extension gap was repeated. Balanced flexion and extension gap (difference between flexion and extension gap ≤ 3mm) was confirmed in 99 cases (94%). A mobile bearing prosthesis (e motion FP, B.Braun Aesculap) was used.

One patient (bilateral TKAs) died of unrelated causes at postoperative 2 year. One knee was revised due to infection. One hundred three cases were followed up at least more than 4 years, 53 months in average. Overall survival rate is 97%. Average preoperative HHS scores and range of motion (ROM) were 65.4 points (range, 33~82) and 126.8 degrees (80~140). At the last follow-up, HHS score and ROM were 95.0 points (78~100) and 131.4 degrees (110~140). Statistically significant improvement in HHS score and ROM were observed (p< 0.05). The mean mechanical axis was 179.44±1.83° (175~184°) with 8 cases of outliers (more than ±3° of optimum). There was no radiolucency, osteolysis, subsidence, or loosening at the last follow-up.

In conclusion, navigation is an excellent predictor for achieving balanced soft tissue & flexion-extension gap in primary total knee arthroplasty. Navigated TKAs using soft tissue balancing technique showed excellent clinical results and is effective methods achieving accurate mechanical axis and reducing prosthetic alignment outlier.

Introduction: Freezing and storage of fresh frozen femoral heads destined for use in revision hip arthroplasty is thought to result in graft cell death. Washing of the graft following the morsellisation process also removes a large proportion of the marrow content of the allograft. However, the immunological load of the impaction allografting process remains unknown. The aim of this study was to investigate the immune response by observing any changes in peripheral blood lymphocyte subsets in response to allografted bone used in revision hip replacement

Methods: 87 patients were entered into this prospective study and grouped according to whether impaction allograft was used or not. Venous blood samples were collected pre-operatively and at set time intervals up to one year post-operatively. Using flow cytometry, analysis of venous blood allowed counts of the following cells: Helper T-lymphocytes, cytotoxic T-lymphocytes, memory T-lymphocytes, naïve T-lymphocytes, Natural Killer cells and B-lymphocytes.

Results: All patients had a successful outcome at one year. 50 patients with radiologically defined host-graft union were compared with 37 patients who did not receive allograft. Pre-operatively, a significant difference (p=0.03) was found between the groups of patients with respect to Natural Killer cells but other subsets showed no significant difference. Post-operatively the significant difference between Natural Killer cells resolved. T-helper lymphocytes, cytotoxic lymphocytes, memory T-lymphocytes and naïve T-lymphocytes in both groups showed decreases in values immediately post surgery, recovering to normal values within 6 weeks post-surgery. The allograft group showed significant increases from baseline in cytotoxic T-lymphocytes at 6 months (p< 0.01) and memory T-lymphocytes one year postoperatively (p=0.04). B-lymphocyte numbers did not alter significantly from baseline.

Conclusion: Cytotoxic T-lymphocytes recognise HLA-class I molecules which are present on all nucleated cells and have been implicated in having a role in osteoclast regulation. Memory T-lymphocytes are produced after a naïve T-lymphocyte is exposed to an antigen. The observed increases of these subsets were not observed in the non-grafting group suggesting the allografted bone had elicited an immunological response. At 12 months all grafts appeared radiologically stable and the immunological response may have been beneficial to the outcome.

Introduction: The long term success of impaction grafting depends on the remodelling process during incorporation. This project was designed to characterise any differences in the biochemical markers of bone turnover following revision hip arthroplasty performed with or without impaction grafting.

Methods: 87 patients undergoing revision hip arthroplasty were entered into this prospective study and grouped according to whether impaction allograft was used or not. Biochemical markers of bone turnover were assessed pre-operatively and post-operatively on day 2, day 9, week 6, 6 months and 1 year. Osteocalcin, pro-collagen type-I N-terminal propeptide and bone specific alkaline phosphatase were measured as bone formation markers. C-telopeptide, pyridinoline and deoxypyridinoline were measured as bone resorption markers.

Results: All patients had a successful radiological and clinical outcome at one year. 50 patients with radiologically defined host-graft union were compared with 37 patients who did not receive allograft. Markers of bone formation tended to rise by day 9 but the rise in osteocalcin was delayed in the graft group and was significantly lower at 6 months in comparison to the non-graft group (p=0.002). Alkaline phosphatase levels remained significantly elevated at one year in the graft group (p=0.027) whilst levels in the non-graft group had normalised. Markers of bone resorption also rise in both groups but with no significant differences between the groups.

Discussion: Following impaction grafting, new bone formation may be delayed in comparison to revisions performed without graft. The pattern of markers of bone resorption did not differ significantly between the groups suggesting that there is no large scale resorption of the impacted allograft in these cases.

These results provide a biochemical insight into the bone formation and bone resorption processes during allograft incorporation.

Introduction: The long term success of impaction grafting depends on the remodelling process during incorporation. This project was devised to characterise any differences in the biochemical markers of bone turnover following revision hip arthroplasty performed with or without impaction grafting.

Methods: 87 patients were entered into this prospective study and grouped according to whether impaction allograft was used or not. Biochemical markers of bone turnover were assessed pre-operatively and post-operatively on day 2, day 9, week 6, 6 months and 1 year. Osteocalcin, procollagen type-I N-terminal propeptide and bone specific alkaline phosphatase were measured as bone formation markers. C-telopeptide, pyridinoline and deoxypyridinoline were measured as bone resorption markers.

Results: All patients had a successful outcome at one year. 50 patients with radiologically defined host-graft union were compared with 37 patients who did not receive an allograft. Markers of bone formation tended to rise by day 9 but the rise in osteocalcin was delayed in the graft group and was significantly lower at 6 months in comparison to the non-graft group (p=0.002). Alkaline phosphatase levels remained significantly elevated at one year in the graft group (p=0.027) whilst levels in the non-graft group had normalised. Markers of bone resorption also rise in both groups but with no significant differences between the groups.

Discussion: Following impaction grafting, new bone formation may be delayed in comparison to revisions performed without graft. The pattern of markers of bone resorption did not differ significantly between the groups suggesting that there is no large scale resorption of the impacted allograft in these cases.

These results provide a biochemical insight into the bone formation and bone resorption processes during allograft incorporation.

Large concentration of mines, unexploded ordinance and primitive infrastructure in post war Bosnia-Herzegovina poses difficulties in reaching the casualties within the “golden hour”.

As a part of the peacekeeping operation immediate response teams (IRT) are in place to save life and prevent further injury. We studied the efficacy of such a team in Sipovo, Bosnia. It depends on co-ordination between the chain of command and the IRT.

We retrospectively reviewed all our IRT call-outs at Sipovo from April 1999 till December 2001. We noted the response time and the priority state of the patients.

Weather conditions permitting the IRT call-outs has been by helicopter for priority 1 patients. There were 89 IRT call outs in the above mentioned period. The average response time from the call for help to the medical team reaching the patient was 75 minutes. Within that the average flight time was 45 minutes. The priority states at the site and of the casualties at the hospital are: Priority 1 at site 128, Priority 1 at Hospital 23, Priority 2/Priority 3 is 105, Medical Emergencies is 15, and Priority 4 being 9.

The suggested priority state was overestimated in 82% percent of the patients. There was a conflict between the chain of command and clinical judgement resulting from multiple levels of communication. However we felt the presence of the IRT was not only clinically efficacious but an important factor in uplifting the morale of the peace keeping force.