Olecranon plates used for the internal fixation of complex olecranon fractures are applied directly over the triceps tendon on the posterior aspect of the olecranon. The aim of the study is to describe the relationship of the plates and screws to the triceps tendon at the level of the olecranon. Eight cadaveric elbows were used. Dimensions of the triceps tendon at the insertion and 1cm proximal were measured. A long or a short olecranon plate was then applied over the olecranon and the most proximal screw applied. The length of the plate impinging on the tendon and the level of the screw tract on the tendon and bone were measured. The mean olecranon height was 24.3cm (22.4-26.9cm) with a tip-to-tendon distance of 14.5cm (11.9-16.2cm). The triceps tendon footprint averaged 13.3cm (11.7-14.9cm) and 8.8cm (7.6-10.2cm) in width and length, respectively. The mean width of the central tendon 1 cm proximal to the footprint was 6.8 cm. The long olecranon plate overlay over more movable tendon length than did the short plate and consequently the superior screw pierced the triceps tendon more proximally with the long plate. Using the Mann-Whitney U test, the differences were significant. The long olecranon plates encroach on more triceps tendon than short plates. This may be an important consideration for olecranon fractures with regards implant loosening or triceps tendon injury.
Local infiltration analgesia is a relatively novel technique developed for effective pain control following total knee replacement, reducing requirements of epidural or parenteral post-operative analgesia. The study aimed to investigate the anatomical spread of Local Infiltration Analgesia (LIA) used intra-operatively in total knee arthroplasty (TKA) and identify the nerve structures reached by the injected fluid. Six fresh-frozen cadaveric lower limbs were injected with 180ml of a solution of latex and India ink to enable visualisation. Injections were done according to our standardised LIA technique. Wounds were closed and limbs were placed flat in a freezer at −20°C for two weeks. Limbs were then either sliced or dissected to identify solution locations. Injected solution was found from the proximal thigh to the middle of the lower leg. The main areas of concentration were the popliteal fossa, the anterior aspect of the femur and the subcutaneous tissue of the anterior aspect of the knee. There was less solution in the lower popliteal fossa. The solution was found to reach the majority of the terminal branches of the tibial, fibular and obturator nerves. Overall, there was good infiltration of nerves supplying the knee. The lack of infiltration into the lower popliteal fossa suggests more fluid or a different injection point could be used. The solution that travelled distally to the extensor muscles of the lower leg probably has no beneficial analgesic effect for a TKA patient. This LIA technique reached most nerves that innervate the knee joint which supports the positive clinical results from this LIA technique. However, there may be scope to optimise the injection sites.