Introduction

Debate continues regarding the relative advantages of ceramic-on-ceramic (CoC) and metal-on-polyethylene (MoP) articulations in total hip arthroplasty (THA). Perceived benefits of CoC include longevity, and low wear - in turn limiting the effects of particulate wear debris. However, CoC bearings cost significantly more, and concern remains over the risk of ceramic fracture; a complication not seen with MoP bearings, which are also cheaper.

Introduction

Deep vein thrombosis(DVT) and pulmonary embolism(PE) are well-recognised complications following lower limb arthroplasty (Cohen et al, 2001). The National Institute for Clinical Excellence and British Orthopaedic Association recommend the use of both mechanical and chemical prophylaxis. At our institute regimens have changed reflecting new developments in the use of thombo-prophylaxis. Our aim was to assess the efficacy of these methods in preventing complications.

A reduced range of movement post total knee replacement (TKR) surgery is a well recognised problem. Manipulation under anaesthesia (MUA) is a commonly performed procedure in the stiff post operative TKR. Long term results have been variable in the literature.

We prospectively followed up 48 patients since 1996 from one centre, over an average of 7.5 years, (range 1 to 10 years) and report on the long term results.

The mean time to MUA post TKR was 12.3 weeks (range 3 to 48). Pre MUA, the mean flexion was 53°. The mean immediate passive flexion post MUA was 97°, an improvement of 44° (Range 10° to 90°, CI < 0.05). By one year, the mean flexion was 87°, improvement of 34°, (range −15° to 70°, CI< 0.05). At ten years the mean flexion was 86°.

We found no difference between those knees manipulated before or after 12 weeks. In addition there was no difference found in those knees which had a pre TKR flexion of greater or less than 90°. There were no complications as a result of MUA. However, one patient was eventually revised at two years secondary to low grade infection.

Our findings show that MUA is safe and effective method at improving the range of motion in a stiff post operative TKR. The improvement is maintained in the long term irrespective of time to MUA and range of motion pre TKR

Background: There remains no clear guidance from the British Orthopaedic Association regarding the use of closed suction drains after primary total knee replacement (TKR). Previous studies suggest no benefit in their use and no significant difference between the type of drain used.

Aims: To assess whether allogenic transfusion requirements are altered by the use of closed suction drainage and to establish if drains reduce post-operative complications and length of stay in hospital.

Materials and Methods: 60 patients undergoing TKR in Eastbourne between December 2008 and June 2009 were evaluated pre- and post-operatively. The population was divided into those with no drain, a Redivac drain (fluid discarded) and a re-transfusion drain (fluid filtered and transfused into the patient).

Results: 23 patients had Redivac drains and 5 (22%) required an allogenic blood transfusion. 37 patients had no drain and 2 (5%) required allogenic blood. For the 14 re-transfusion drain patients none received allogenic blood. There was no significant difference in the length of stay across all 3 groups (p=> 0.25). There was a significantly higher incidence of wound ooze and cellulitis in patients with no drain (50%; p=< 0.01). This is in comparison to the other two groups where only 30% of patients with a Redivac drain and 7% of patients with a re-transfusion drain experienced these complications. There was no significant difference in the average haemoglobin drop between the 3 groups (p=> 0.1).

Conclusions: The results suggest a benefit in using drains to reduce the risk of post-operative wound ooze and cellulitis after TKR. Re-transfusion drains also appear to reduce the requirement for allogenic blood transfusion in the post-operative period.

Aims: Replacing human cadaveric specimens with fresh frozen animal tissue in biomechanical studies has become increasingly more popular due to the scarcity of young human tissue. The aims of this study were to characterise and compare the biomechanical parameters of tailored strips of equine extensor tendon, with 4 strand young human semitendinosus and gracilis (STG) tendons as an alternative tendon model for testing anterior cruciate ligament (ACL) graft reconstruction techniques using the Soffix Polyester ACL fixation device.

Method: Common digital extensor tendons were harvested from normal equine forelimbs and tailored into 5 mm wide, 2 strand equine tendon strips. The doubled equine tendons were overlapped and braided around the buttonholes of a Soffix fixation device and secured with No 2 Ethibond sutures (Johnson & Johnson Ltd). The Soffix-4-strand young human STG tendon complex was prepared in an identical manner. Mechanical testing was performed measuring ultimate tensile load (UTL) and elongation to failure (EF), structural stiffness (SS) was calculated from load extension curves.

Results: The Soffix-STG and the equine tendon complexes produced a mean UTL of 1186 N +/− 113.89 and 1116 N +/− 208.5 respectively showing no statistically significant difference.

Conclusions: We conclude that a tailored 5mm wide 2-strand equine extensor tendon strip provides a comparable alternative for in vitro testing of young human four strand STG tendon graft using a Soffix polyester fixation device.

Aims: The aims of this study were to evaluate the biomechanical properties and mode of failure of a technique of anterior cruciate ligament (ACL) reconstruction using the Soffix polyester fixation device. A 2-strand equine extensor tendon graft model was used because a previous study has shown it to have equivalent bio-mechanical properties to that of 4-strand human semitendinosus and gracilis tendon grafts.

Method: Ten stifle joints were obtained from 5 skeletally mature pigs, the soft tissues were removed and the ACL and PCL were sacrificed. Tibial tunnel preparation was standardised using the Mayday rhino horn jig to accurately position a guide wire over which an 8mm tunnel was drilled. A 2-strand equine tendon-Soffix graft was used to reconstruct the ACL of the porcine knee using over the top femoral placement with bicortical screw fixation. Mechanical testing of 10 specimens was performed.

Results: The mode of failure included 4 midsubstance tendon failures, 3 Soffix failures and 3 failures at the suture-Soffix interface. The mean ultimate tensile load for the ACL reconstruction was 1360 N (standard deviation (SD) =354), elongation to failure of 41 mm (SD=7.5) and a structural stiffness of 35 N/mm (SD=8.1).

Conclusion: This in vitro study has shown that the technique of ACL reconstruction using the Soffix soft tissue fixation device with a tendon graft placed in the over the top position is biomechanically strong, providing a sufficiently high UTL immediately following reconstruction, therefore allowing early weight bearing and rehabilitation.

The most common indication for knee arthrodesis is pain and instability in an unreconstructable knee following an infected knee arthroplasty. In this study, we compare the use of the Mayday arthrodesis nail (Ortho-dynamics, Christchurch, UK) versus external fixation, Orthofix (Berkshire UK) and Stryker Hoffman II (County Cork, Ireland).

All patients in this study underwent arthrodesis between 1995 and 2006 at Conquest Hospital, Hastings. In group A, 11 patients underwent arthrodesis with a Mayday nail. In all cases, the indications were infected total knee replacements (TKR). Three of these patients previously had failed attempts at arthrodesis with external fixation devices. In group B, seven patients underwent arthrodesis using external fixation. In six patients, the indication was infected TKRs. Results were reviewed retrospectively, with union assessed both clinically and radiologically.

The mean inpatient stay for the Mayday nail group was 23 days (range 8 – 45 days) compared with 76 days (range 34 – 122) for the external fixation group (p< 0.01, CI 95). Ten patients in group A went on to confirmed primary arthrodesis. One patient underwent revision arthrodesis with a Mayday nail and subsequently united. In group B only two patients achieved union. The rate of union was significantly greater in the Mayday nail group than the external fixation group (91% vs 29%, p< 0.01). Of those patients that achieved union, there was no difference in the time to fusion between groups.

Our study supported the existing literature and found that the Mayday nail appeared more effective than monoaxial external fixators for arthrodesis in the management of infected total knee replacements.

Aims: The aims of this study were to evaluate the biomechanical properties and mode of failure of a technique of anterior cruciate ligament (ACL) reconstruction using the Soffix polyester fixation device. A 2-strand equine extensor tendon graft model was used because a previous study has shown it to have equivalent bio-mechanical properties to that of 4-strand human semitendinosus and gracilis tendon grafts.

Method: Ten stifle joints were obtained from 5 skeletally mature pigs, the soft tissues were removed and the ACL and PCL were sacrificed. Tibial tunnel preparation was standardised using the Mayday rhino horn jig to accurately position a guide wire over which an 8mm tunnel was drilled. A 2-strand equine tendon-Soffix graft was used to reconstruct the ACL of the porcine knee using over the top femoral placement with bicortical screw fixation. Mechanical testing of 10 specimens was performed.

Results: The mode of failure included 4 midsubstance tendon failures, 3 Soffix failures and 3 failures at the suture-Soffix interface. The mean ultimate tensile load for the ACL reconstruction was 1360 N (standard deviation (SD) =354), elongation to failure of 41 mm (SD=7.5) and a structural stiffness of 35 N/mm (SD=8.1).

Conclusion: This in vitro study has shown that the technique of ACL reconstruction using the Soffix soft tissue fixation device with a tendon graft placed in the over the top position is biomechanically strong, providing a sufficiently high UTL immediately following reconstruction, therefore allowing early weight bearing and rehabilitation.