This review summarises the opinions and conclusions reached from a symposium on infected total knee replacement (TKR) held at the British Association of Surgery of the Knee (BASK) annual meeting in 2011. The National Joint Registry for England and Wales reported 5082 revision TKRs in 2010, of which 1157 (23%) were caused by infection. The diagnosis of infection beyond the acute post-operative stage relies on the identification of the causative organism by aspiration and analysis of material obtained at arthroscopy. Ideal treatment then involves a two-stage surgical procedure with extensive debridement and washout, followed by antibiotics. An articulating or non-articulating drug-eluting cement spacer is used prior to implantation of the revision prosthesis, guided by the serum level of inflammatory markers. The use of a single-stage revision is gaining popularity and we would advocate its use in certain patients where the causative organism is known, no sinuses are present, the patient is not immunocompromised, and there is no radiological evidence of component loosening or osteitis.

It is our opinion that single-stage revision produces high-quality reproducible results and will soon achieve the same widespread acceptance as it does in infected hip arthroplasty.

There is a recognised incidence of anterior knee pain following Anterior Cruciate Ligament (ACL) reconstruction using a patella tendon autograft.

This study examined two group of patients both pre ACL ligament reconstruction and post ACL reconstruction using patella tendon grafts to define if anterior knee pain is a result of patella tendon harvest or a primary consequence of an ACL injury.

The two groups of patients were best matched for age, sex and physical activity.

The pre-operative group of twenty-five patients had a confirmed ACL rupture and exhibited symptoms of instability requiring an ACL reconstruction.

The operative group of twenty-five patients were a minimum of a year post operation.

The graft was harvested by an open procedure and the graft bone blocks were secured with interference screws.

The patients’ anterior knee pain score was assessed using the Shelbourne scoring system that evaluates knee function in relation to anterior knee pain using five parameters. The maximum score is 100.

The scores were compared using the unpaired student test.

There was no significant age difference between the two groups, preoperative group age 32. 2 years (range 22 to 46) and postoperative age 34. 8years (range 19 to 48).

The mean anterior knee pain score for the preoperative group was 71. 6 (49 to 100), the postoperative group was 77. 7 (45 to 100), this was not significantly different.

We found no significant difference in knee function due to anterior knee pain between the two groups. Studies have shown significant anterior knee pain following hamstring reconstruction (Spicer).

This study shows anterior knee pain in the ACL deficient knee is present prior to surgery.

We conclude that patella tendon autografts produce no significant incidence of anterior knee pain post surgery.

Purpose: Posters of study: To produce a virtual reality model of prosthetic knee joint motion, giving detail regarding contact area and contact pressures during the process of walking.

Method: Using serial CT scans and data regarding the material properties of bone, cartilage, ligaments and other soft tissue structures a computational “virtual reality model” of the knee has been constructed. This computational model which is a 3D dynamic representation of a human knee joint, may be programmed to replicate the standard gait pattern of the human knee.

This study details the development of this model and its validation against the accepted Stenmore Test Rig for modelling of knee joint movement and knee prosthetic wear. The validation results will be presented,

The model allows the calculation and representation of contact pressures and contact areas in the knee joint as it moves through the gait cycle. This study also shows the effect of uni-condular loading and varus mal-positioning which may occur at surgery and the effect this has on the contact area and contact pressures of a prosthetic knee in ambulation. The resultant gait pattern produced by uni-condular loading and exhibited by the virtual knee closely resembles that seen in In Vivo Kinematic Studies reported by other authors.

In conclusion we present this as a valid computational dynamic model of knee prosthetic wear and kinematics which represents an enormous advantage over standard mechanical testing and presents possibilities for rapid analysis in new knee joint designs and the effect of abnormalities of gait and wear.