Purpose: Continuous femoral nerve block (CFNB) has been revealed to be a safe and effective method to decrease postoperative pain after total knee arthroplasty (TKA).

However, optimal duration for CFNB to decrease pain and accelerate rehabilitation program after TKA has not been addressed. We, therefore, compared three groups of patients which had different duration of CFNB (0, 2, and 5days) in this study.

Methods: Sixty patients who received primary TKA for osteoarthritis were divided into three groups based on the duration to receive CFNB for 0day, 2days or 5days (twenty patients for each group). Ropivacaine 2mg/mL was given through the femoral nerve catheter using elastomeric infusers (delivering 2ml/hr for each group).

Outcomes including visual analog scale (VAS) pain scores and range of motion (ROM) were compared at 1st, 3rd, 6th, 14th and 21th days after surgery. In addition, the postoperative date when patients could walk stably with parallel bar, walker, or T-cane were recorded and compared.

Results: At 1st and 3rd day postoperatively, the VAS was significantly better in the CFNB 2 days and CFNB 5 days group than in the CFNB 0 day group (P< 0.05).

ROM did not show significant difference among the three groups over postoperative days 1st to 21st (P> 0.05), although groups with the CFNB showed greater ROM at all time points. The CFNB 5 days group obtained stable walking ability with T-cane earlier than other groups (P< 0.05). No patient had any side effect by having CFNB in this study.

Discussion: Postoperative use of CFNB reduced pain at first 3days, and shorten the time to acquire stable walking ability after TKA. We conclude that CFNB should be kept for 5days after surgery to decrease pain and accelerate rehabilitation program after TKA.

We have developed a new tensor for total knee replacements which is designed to assist with soft-tissue balancing throughout the full range of movement with a reduced patellofemoral joint. Using this tensor in 40 patients with osteoarthritis we compared the intra-operative joint gap in cruciate-retaining and posterior-stabilised total knee replacements at 0°, 10°, 45°, 90° and 135° of flexion, with the patella both everted and reduced.

While the measurement of the joint gap with a reduced patella in posterior-stabilised knees increased from extension to flexion, it remained constant for cruciate-retaining joints throughout a full range of movement. The joint gaps at deep knee flexion were significantly smaller for both types of prosthetic knee when the patellofemoral joint was reduced (p < 0.05).

We isolated multilineage mesenchymal progenitor cells from haematomas collected from fracture sites. After the haematoma was manually removed from the fracture site it was cut into strips and cultured. Homogenous fibroblastic adherent cells were obtained. Flow cytometry revealed that the adherent cells were consistently positive for mesenchymal stem-cell-related markers CD29, CD44, CD105 and CD166, and were negative for the haemopoietic markers CD14, CD34, CD45 and CD133 similar to bone-marrow-derived mesenchymal stem cells. In the presence of lineage-specific induction factors the adherent cells could differentiate in vitro into osteogenic, chondrogenic and adipogenic cells.

Our results indicate that haematomas found at a fracture site contain multilineage mesenchymal progenitor cells and play an important role in bone healing. Our findings imply that to enhance healing the haematoma should not be removed from the fracture site during osteosynthesis.

We have investigated whether cells derived from haemarthrosis caused by injury to the anterior cruciate ligament could differentiate into the osteoblast lineage in vitro. Haemarthroses associated with anterior cruciate ligament injuries were aspirated and cultured. After treatment with β-glycerophosphate, ascorbic acid and dexamethasone or 1,25 (OH)₂D₃, a significant increase in the activity of alkaline phosphatase was observed. Matrix mineralisation was demonstrated after 28 days and mRNA levels in osteoblast-related genes were enhanced.

Our results suggest that the haemarthrosis induced by injury to the anterior cruciate ligament contains osteoprogenitor cells and is a potential alternative source for cell-based treatment in such injury.

We undertook 114 arthroscopic meniscal repairs in 111 patients and subsequently carried out second-look arthroscopy to confirm meniscal healing at a mean of 13 months after repair. Stable healing at the repaired site was seen in 90. Of these, however, 13 had another arthroscopy later for a further tear. The mean period between the repair and the observation of a repeat tear was 48 months. Of the 13 patients, 11 had returned to high activity levels (International Knee Documentation Committee level I or II) after the repair.

An attempt should be made to preserve meniscal function by repairing tears, but even after arthroscopic confirmation of stable healing repaired menisci may tear again. The long-term rate of healing may not be as high as is currently reported. Second-look arthroscopy cannot predict late meniscal failure and may not be justified as a method of assessment for meniscal healing. Young patients engaged in arduous sporting activities should be reviewed regularly even after arthroscopic confirmation of healing.