Objective

The aim of this study was to investigate the clinical results of treatment for patients with periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) in our department.

Purpose: Intervertebral disc (IVD) degeneration is associated with proteolytic degradation of proteoglycan aggregates present within the extracellular matrix of the disc. Link-N peptide is the N-terminal peptide of link protein, which stabilizes the proteoglycan aggregates. It is generated in vivo by proteolytic degradation during tissue turnover. We have previously shown that this peptide can stimulate the synthesis of proteoglycans and collagens by IVD cells in vitro. However, to date, there have been no reports on the effect of Link-N on the IVD in vivo. The purpose of the present study was to determine the effect of intradiscally administration of Link-N peptide on disc cell survival and extracellular matrix synthesis using a rabbit annular needle puncture model of IVD degeneration.

Method: Twelve New Zealand white rabbits (~3.5 kg; 5–6 months old) received an annular puncture with an 18-gauge needle on 2 non-contiguous discs (L2–L3 and L4–L5). The disc (L3–L4) between the punctured discs and that above (L5–L6) was left intact as internal controls. Two weeks after the initial puncture, the anterior surfaces of the previously punctured discs (L2–L3 and L4–L5) were injected with either saline (10 μl/disc) or Link-N (100 μg in 10μl saline/disc) into the center of the NP. Disc height was radiographically monitored biweekly. After 12 weeks post-injection, all the rabbits were euthanized and the IVDs from both experimental groups were removed from each lumbar spine for biochemical analysis. The nucleus pulposus (NP) was separated from the annulus fibrosus (AF), the specimens weighed (wet weight), the content of DNA measured using PicoGreen, and the total contents of sulfated glycosaminoglycans (GAG) measured by the 1,9-dimethylmethylene blue (DMMB) assay.

Results: Following needle puncture that initiates disc degeneration, the disc height index (DHI) decreased by about 25%. By 6 weeks after Link-N injection, the mean percent DHI of injected discs in the Link-N group was higher than in the saline group. This difference in mean percent DHI was maintained during the rest of the follow-up. Puncturing the IVD also led to a decrease in proteoglycan content in both the NP and the AF in saline-treated discs. Treatment with Link-N stimulated proteoglycan synthesis (GAG) in both the NP and AF by about 20%. Link-N did not cause an increase in the DNA content of the discs.

Conclusion: Results of the present study show that Link-N can stimulate proteoglycan production in vivo when administered to degenerate disc. This stimulation occurs in both the NP and AF of the disc and in the absence of any effect on cell division. The changes observed with Link-N on proteoglycan synthesis are similar to those reported after injection of osteogenic protein-1 (OP-1) Thus, Link-N appears to be equally effective at stimulating repair of the IVD in vivo. One major advantage of Link-N over OP-1 for therapeutic use is the large saving in cost, Link-N being about 400 times cheaper than OP-1.

Objective: The aim of this study was to evaluate the safety and efficacy of sequential bilateral total knee arthroplasty (TKA) for patients with rheumatoid arthritis (RA), in comparison with staged bilateral and unilateral TKA.

Patients and Methods: Between July 2000 and June 2005, 340 TKA were performed in our department. We investigated retrospectively the clinical data of each patient, including the peri-operative data such as the surgical time, the amount of haemorrhage and postoperative adverse events. We also examined the clinical outcome before and after bilateral TKA by using the Japanese Orthopaedic Association (JOA) evaluation chart of knee joint function (JOA score).

Results: We have done sequential bilateral TKA for 60 knees of 30 patients (group A), staged bilateral TKA for 26 knees of 13 patients (group B) and unilateral TKA for 254 knees (group C). Before TKA, the mean JOA score were 44.9, 40.1, 46.4 points, and the mean range of motion of affected knees were 14.6–113.6°, 27.9–89.6°, 14.1–116.9° in group A, B and C, respectively, indicating that group B included more severe cases. Whereas the mean surgical time were 136.4, 158.4, 154.3 minutes, the mean amount of peri-operative haemorrhage were 414.6, 273.4, 277.7 ml in group A, B and C, respectively. Although we experienced 1 case with symptomatic pulmonary embolism in group A, which was successfully treated, there was none of cases with death within 1 month of surgery or early-phase infection. The JOA score at final follow-up (the mean follow-up period was 1 year and 8 months) were 91.1 and 86.9 points in group A and B, respectively, showing good results in both groups.

Conclusion: In short-term data, sequential bilateral TKA was successfully performed and beneficial approach to patients with RA. The intensive pre- and post-operative management could be essential for good clinical outcome. Further improvement should be needed to perform this procedure more safely and prevent complications, especially serious cardiopulmonary events.