Aim

To investigate the validity of threshold values for the Oxford Hip and Knee Score (OHS and OKS) for treatment success 12 months after total knee or hip replacement.

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.

Recent debate about changing population demographics and growing demands of younger patients has suggested a future explosion in the requirements for primary and revision lower limb arthroplasty (TKA/THA). This could represent a significant challenge for healthcare providers. This study aimed to predict the demands for lower limb arthroplasty in Scotland from 2010–2035.

Population figures (2004–2010) and projected population data (five year increments) were obtained from the National Records of Scotland. The numbers of arthroplasties from 2004–2010 were provided by the Scottish Arthroplasty Project. Data were divided into three age groups (40–69, 60–79, 80+). The first model used mean incidence for each age group from 2006–2010 applied to the projected population figures. The second used linear regression to give predicted incidences 2015–2035 which were then applied to the projected population. The third-for revisions – used incidence per number of primary arthroplasties.

For primary TKA model 1, comparing to 2010, showed demand increasing by 10% in 2020 and by 31% (to 8,650 procedures) in 2035. Model 2 gave increases of 60% and 161% respectively. An increase was found across all age groups with 60–79 more than doubling and 80+ increasing fourfold by 2035 (model 2). The revision TKA models predicted between 670 and 2,000 procedures by 2035. For primary THA models 1 and 2 showed demand increasing by 40% in 2020 and then by 60% and 110% (11,000 and 14,500 procedures) in 2035 respectively. All age groups had increasing demand with 60–79 doubling and 80+ tripling by 2035 (model 2). The revision THA models predicted between 1,300 and 2,100 procedures by 2035.

These projections show large increases in the numbers of both primaries and revisions over the next two decades. They highlight that current resources may be insufficient or the selection criteria for surgery may need to be revisited.

Patients undergoing total knee arthroplasty (TKA) experience significant post-operative pain. We report the results of a new comprehensive patient care plan to manage peri-operative pain, enable early mobilisation and reduce length of hospital stay in TKA.

A prospective audit of 1081 patients undergoing primary TKA during 2008 and 2009 was completed. All patients followed a planned programme including pre-operative patient education, pre-emptive analgesia, spinal/epidural anaesthesia with propofol sedation, intra-articular soft tissue wound infiltration, post-operative high volume intermittent ropivacaine boluses with an intra-articular catheter and early mobilisation. The primary outcome measure was the day of discharge from hospital. Secondary outcomes were verbal rating pain scores on movement, time to first mobilisation, nausea and vomiting scores, urinary catheterisation for retention, need for rescue analgesia, maximum flexion at discharge and six weeks post-operatively, and Oxford score improvement.

The median day of discharge to home was post-operative day four. Median pain score on mobilisation was three for first post-operative night, day one and day two. 35% of patients ambulated on the day of surgery and 95% of patients within 24 hours. 79% patients experienced no nausea or vomiting. Catheterisation rate was 6.9%. Rescue analgesia was required in 5% of cases. Median maximum flexion was 85° on discharge and 93° at six weeks post-operatively. Only 6.6% of patients had a reduction in maximum flexion (loss of more than 5°) at six weeks. Median Oxford score had improved from 42 pre-operatively to 27 at six weeks post-operatively. The infection rate was 0.7% and the DVT and PTE rates were 0.6% and 0.5% respectively.

This multidisciplinary approach provides satisfactory post-operative analgesia allowing early safe ambulation and discharge from hospital. Anticipated problems did not arise, with early discharge not being detrimental to flexion achieved at six weeks and infection rates not increasing with the use of intra-articular catheters.