Revision total knee arthroplasty (TKA) is a complex procedure which carries both a greater risk for patients and greater cost for the treating hospital than does a primary TKA. As well as the increased cost of peri-operative investigations, blood transfusions, surgical instrumentation, implants and operating time, there is a well-documented increased length of stay which accounts for most of the actual costs associated with surgery.

We compared revision surgery for infection with revision for other causes (pain, instability, aseptic loosening and fracture). Complete clinical, demographic and economic data were obtained for 168 consecutive revision TKAs performed at a tertiary referral centre between 2005 and 2012.

Revision surgery for infection was associated with a mean length of stay more than double that of aseptic cases (21.5 vs 9.5 days, p < 0.0001). The mean cost of a revision for infection was more than three times that of an aseptic revision (£30 011 (sd 4514) vs £9655 (sd 599.7), p < 0.0001).

Current NHS tariffs do not fully reimburse the increased costs of providing a revision knee surgery service. Moreover, especially as greater costs are incurred for infected cases. These losses may adversely affect the provision of revision surgery in the NHS.

Cite this article: Bone Joint J 2015;97-B:197–201.

Purpose of study

The aim of this study is to evaluate the role of low intensity pulsed ultrasound, Exogen in the treatment of delayed and non unions. Methodology: We conducted a retrospective study of 292 patients who has had Exogen treatment for delayed and non union from 2005 to 2009. Patient's age, sex, associated co morbidities, smoking history, medications, type of fractures (open/closed), infection and site of fractures were sought for. 271 patients' data (228 delayed and 43 non unions) were available during the study with mean age of 53.5 yrs.

Exogen therapy was initiated at 3–4 months for delayed unions and 6–12 months for non unions in 61 tibia (15 open); 31 femur (2 open); 20 scaphoid; 38 5th metatarsal; 31 ankle (2 open); 17 ulna (1 open); 15 radius (3 open); 29 humerus (2 open); 16 clavicles; 6 olecranon; 4 pilon (2 open) and 2 metacarpal fractures.