Introduction: The benefits of postoperative wound drainage in patients with total knee arthroplasty (TKA) with regards to mobilisation and wound healing were studied. We wanted to determine the efficacy of an autologous blood retransfusion system.

Materials and Methods: 150 patients with TKA were divided into three groups of 50 patients:

A) Three wound drainages with an autotransfusion system and suction;

Haemoglobin values, blood transfusion requirements, blood loss, postoperative range of motion, knee society score and rate of complications were observed and recorded. All patients were operated without tourniques for lower blood loss during total knee replacement.

Results: In the group of patients with wound drainage and a retransfusion system the requirement of postoperative additional blood transfusion was not significantly less than in the group without wound drainage. Group A had the most blood loss of all. The group without wound drainage had more haematoma and wound healing complications. Best results were observed within the group with one intraarticular drainage without suction. The rate of complications was not increased and the blood transfusion requirements were the lowest.

Conclusion: This study shows that total knee replacement involving one intraarticular wound drainage without suction attains the best results. During the last four years we used this wound drainage technique in 787 TKAs and can confirm all findings of this study.

The use of stem cells in tissue engineering has emerged as a promising therapy for the repair of bone and cartilage defects. Targeted delivery of stem cells requires a substrate to maintain the cells at the repair site, as well as to provide the physical cues, such as mechanical strain, for encouraging differentiation and expression of the mature cell phenotype. The strains that will be generated in cells residing on the scaffold is dependent on the scaffold material, as well as both the fibre thickness and the fibre orientation in the scaffold. To encourage uniform bone matrix generation throughout the scaffold, it is desirable that the strain be uniformly distributed and that the internal pore architecture be precisely controlled to maximise media diffusion. This requires an optimised scaffold design and a manufacturing technique that allows for precise control over the scaffold’s internal architecture.

Scaffold architecture was optimised by performing a series of finite element analyses (FEA) on computer aided design (CAD) models of Polycaprolactone (PCL) scaffolds. The mechanical properties of PCL were used to yield an accurate strain profile of scaffolds with different fibre orientations. Having determined the optimal scaffold geometry, PCL scaffolds were manufactured using a fibre deposition technique that yielded three-dimensional objects with this geometry. During manufacture, a PCL solution was extruded into a non-miscible solvent which precipitated out PCL fibres in repetitive layers. Of the geometries tested with FEA, a 90 degree rotation of adjacent layers with a 50% offset of parallel strands was found to provide the optimal strain distribution (60% increase in surface exposed to strain). Histomorphometry was used to assess the exact dimensions of the scaffold produced. Fibre spacing was found to be precisely controlled to 380 +/- 10 microns within the layers and the fibre thickness was controlled to 270 +/- 10 microns.

This demonstrates that FEA can be used to predict the strain distribution of different CAD models and that the fibre deposition solvent extrusion technique can be used to accurately manufacture PCL scaffolds that match the desired architecture.

The aim of this study was to establish the consensus of opinion amongst trauma surgeons for the management of displaced supracondylar fractures of the humerus in children.

We carried out a postal questionnaire involving 130 orthopaedic surgeons with an interest in paediatric trauma. They were identified as being members of the British Society for Children’s Orthopaedic Surgery.

We received a response rate of 65%. One third of respondents believe that in uncomplicated fractures, reduction should occur within 6 hours of injury and one half felt that ‘pulseless’ fractures should be treated in the same time frame. 60% said they would explore a pulseless arm after midnight, but only 20% would reduce and stabilise uncomplicated fractures. 82% of surgeons stabilise displaced grade III fractures with K wires, of these, the majority would use a‘crossed’ configuration. If after stabilisation the arm remained pulseless, only 16% said they would explore the brachial artery immediately, 23.5% would seek a vascular opinion and 60.5% of surgeons would observe for 24 hours. If the arm remained pulseless but pink after 24 hours, the majority of surgeons would continue to observe and rely on collateral circulation for distal perfusion.

The majority of surgeons would stabilise displaced supracondylar fractures as soon as possible but not after midnight unless the arm was pulseless. If the hand remained pink but pulseless, most felt that continued observation beyond 24 hours was acceptable.

Introduction: With the introduction of out-patient waiting time targets, there has been increasing pressure on clinics to accommodate both new referrals and follow-up patients. Departments have found it increasingly difficult to continue long-term follow-up of patients post arthroplasty.

We have piloted a new system of purely therapist led clinics and assessed this with an anonymous patient survey.

Method: Since 2005 and following a training program for the therapists involved, 110 arthroplasty patients have passed through the new clinics. They are seen at 6 weeks, 6 and 12 months and then 3, 5 and 10 years. Their ROM, stability and XRAY findings are documented and each patient completes Oxford Knee, SF 12 and WOMAC scores. If there are problems at any stage they are seen in the surgeon led clinic.

Results: 69% of patients responded to the survey and in general they were very satisfied with the new system. 75% felt that been seen by the therapist alone still fully addressed their needs with 79% having an overall impression of either excellent or very good. The patients rated the therapists professionalism, assessment and information delivery as good to excellent in over 80%.

Conclusion: We feel that with the introduction of this new system, we will be able to continue long-term follow-up of all our patients post arthroplasty. With their regular assessments and scoring we will be able to monitor the success of their replacements and theoretically identify early any problems.

Bone substitutes have emerged as a promising alternative in surgeries requiring bone grafting, with a large array of materials available for today’s surgeon. Unfortunately, there is currently no definitive method for comparing the potential bone-healing potential of these different materials. We have developed a novel technique for assessing the osteogenic capacity of different bone substitutes in a mechanically-stimulating perfusion bioreactor.

The Zetos(TM) bioreactor system consists of individual flow chambers connected to a low-flow perfusion pump, which recirculates media through samples. The Zetos can be programmed to apply a controlled stress or a controlled strain to each individual sample inside the flow chamber. Since bone formation has been shown to be optimal with short doses of high amplitude strains, test samples were subjected to daily loading corresponding to physiological strain experienced during a jumping exercise (maximum 3000 microStrain).

Three substitute materials representing the range of materials available clinically were tested in the Zetos system; these included collagen, calcium phosphate, and a synthetic polymer. Primary human osteoblasts were seeded onto the substitutes, which were then placed inside the Zetos system and maintained under load or non-load conditions for 14 days. No supplementary osteogenic factors were provided to the cells. The degree of bone formation in the samples was assessed using Von Kossa staining and quantified in terms of the area of new mineral relative to the surface area of the substitute.

No mineralisation was detected in the non-loaded samples. However, in the loaded samples, mineralisa-tion was detected in some of the substitutes. The degree of mineralisation depended on the material: in collagen, an average of 0.22 mm2/mm2 was mineralised; in calcium phosphate, mineralisation averaged 0.0013 mm2/ mm2; but in the loaded polymer samples, no mineralisation was detected.

This indicates that mechanical loading is a sufficient stimulus for bone formation in some materials, even in the absence of other known osteogenic factors. Further, commercial substitutes differ in their ability to support bone formation under conditions of physiological loading. Further development of this technique could allow it to be used as a screening tool for predicting the efficacy of commercial products.

We compare the management and outcome of two management stratergies for the perfused but pulseless hand following stabilisation of grade III supracondylar fractures in children.

For this study we looked at 15 patients treated in two centres (all treated by the senior author) between 1995 and 2004. The patients were designated to group I if the pulseless hand had been observed or group II if they underwent immediate exploration. Data collected included time to surgery, neurological deficit, time to return of pulse and subsequent symptoms of forearm claudication. All patients were seen at week 1,3 and followed for at least 6 months post surgery. Radiographs were reviewed to determine the adequacy of reduction of the fracture.

The mean age of patient was 3.8 years. Median time to surgery was 6 hours. 6 children had evidence of anterior interosseus nerve palsy. 12 cases were reduced anatomically, 3 had minimal fracture gap. Of the 8 patients in group I (observation) 2 had secondary exploration and one developed claudication symptoms. All had palpable radial pulse at 3 months.6 of the 7 patients in group II (exploration) were seen to have brachial artery tethering, 2 with median nerve entrapment. 5 of them had subsequent return of radial pulse within 24 hours.

Satisfactory radiological reductionof the fracture does-not exclude vessel or nerve entrapment. We would advocate early exploration of the artery if the pulse does not return within 24 hours.

Background: There is no consensus on the best treatment of complex intraarticular fractures and high energy diaphyseal fractures of the long bones. The Locking Compression Plate (LCP) and the Less Invasive Stabilization System (LISS) are the new implants with angular stability developed by the AO/ASIF. The new screw-plate systems seem to offer an excellent alternative for the operative fixation in these cases.

Patients and methods: In a prospective study the new system was used to treat 20 patients (8 women, 12 men; average age 39.3 yrs) with 23 high – energy injuries (multifragmentary shaft fractures or complex intraarticular) from december 2001. During a mean period of 20 (13–30) months, complications, clinical and radiographic findings were followed prospectively. One patient was lost to follow-up. 19 patients underwent a standardized follow-up examination. According to the AO classification, 6 were proximal tibial fractures 41-C; 4 distal tibial 43-C; 6 distal femoral 33-C; 3 humerus 12-C and 4 distal radius 23-C. Ten of the fractures were open, 6 grade II, and 4 grade III. Because of severe concomitant injuries, 4 fractures were first treated with an external fixator and definitively stabilized more than two weeks after the injury. 2 patients were operated on after failure of others implants and non-union.

Results: The outcome correlated with the severity of the fracture, anatomic reduction, exact positioning of the plate and concomitant injuries. Despite the large number of open and comminuted fractures no serious complications as deep infections, vascular lesions, DVT or non-unions were presented.

Conclusions: We found the new internal fixator system to be a safe and reliable procedure. The new system offers numerous fixation possibilities and has proven its worth in complex fracture situations and in revision operation. A good knowledge of biomechanics is essential as well as precise preoperative planning.

Background: Paediatric spinal systems made from stainless steel are effective at correcting early onset scoliosis in a non-fusion technique. The use of similar systems manufactured from titanium is an attractive alternative as it would allow Magnetic Resonance Imaging of the patient with its recognised imaging advantages.

Objective: We performed a prospective in vitro study to compare the mechanical performance of a current clinically used stainless steel construct with an identical proposed titanium alternative.

Methods: Twelve spinal constructs of each material were constructed in a typical in vivo configuration using a corpectomy model in accordance with ASTM F1798 standard. Five samples for each metal were subjected to axial compressive static loading at a rate of 1mm/s until plastically deformed. Seven samples for each metal were then subject to varying compressive cyclic loads until a 5 million cycle run out was observed. From this data a fatigue S-N curve was generated.

Results: The stiffness of each construct was then calculated and the results were statistically analysed. For steel and titanium we calculated 95% confidence intervals of 23.9 to 35.7 and 18.8 to 23.7 respectfully. Significance P(< 0.05). The fatigue strength to 5 million cycles was 179N and 150N for steel and titanium respectfully. Failure occured most commonly in the rods close to the transverse rod connector or the pedicle screw / polyethylene block interface.

Conclusions: We conclude that with identical dimensions, the stainless steel constructs had a significantly higher Modulus of Elasticity than titanium. The fatigue strength for steel was also higher than titanium. The potential use of titanium as an alternative to stainless steel in paediatric spinal systems is still an attractive alternative. Given the results, we would suggest that further re-designing and testing be carried out before clinical release and then initially be reserved for selected patients with lower body weight or physical demands.

Between 1972 and 1990, we performed 168 primary low-friction arthroplasties in 125 patients with acetabular protrusion. Twelve hips were lost to follow-up within eight years and eight which became infected were excluded from the final study. Of the 148 hips remaining, 62 with a mild protrusion were classified as group 1, 54 with moderate or severe protrusion as group 2 and, after 1985, 32 with moderate and severe protrusion which required bone grafts as group 3. The mean follow-up was 18.3 years (3 to 24) for group 1, 17.4 years (8 to 22) for group 2 and ten years (8 to 13) for group 3.

There were 31 revisions of the cup, 12 in group 1 and 19 in group 2. According to the Kaplan-Meier analysis the overall rates at 20 years were 21 ± 10.79% in group 1 and 37 ± 11.90% in group 2. There have been 43 radiological loosenings: 22 in group 1, 21 in group 2 and none so far in group 3, at ten years. The overall loosening rates at 20 years were 42 ± 14.76% in group 1 and 49 ± 19.50% in group 2. The grafts were well incorporated in all group-3 hips, and the bone structure appeared normal after one year.

The distance between the centre of the head of the femoral prosthesis and the approximate true centre of the femoral head was less in group 3 than in groups 1 and 2 (p < 0.01). According to the Cox proportional-hazards regression this was the single most important factor in loosening of the cup (odds ratio 1.11; 95% CI 1.05 to 1.18/mm). Better results were obtained in moderate and severe protrusions reconstructed with bone grafting than in hips with mild protrusion which were not grafted.

We examined ten femoral veins with duplex ultrasound during total hip replacement to demonstrate the operative manoeuvres which cause venous obstruction and to assess prophylactic measures which may overcome it. Exposure of the acetabulum by distraction of the femur with a hook was less likely to occlude flow than retraction with bone levers. Adequate exposure of the femoral shaft by adduction, flexion and either internal or external rotation caused cessation of flow in all cases. In four cases an A-V Impulse System foot pump was activated during periods of stasis. In each case it overcame the obstruction and produced peak velocities which were twice that of the resting state. In five cases, towards the end of the procedure, debris was seen travelling proximally through the femoral vein.