[Transplantation of the meniscus. Experimental study]. / La transplantation de ménisque. Etude expérimentale.

An experimental study has been made of the possibility of meniscus grafting. This was carried out in 30 merino sheep, 15 of which received lyophilised homologous menisci and 15 others deep-frozen homologous menisci. Three sheep had to be excluded because of wound breakdown and sepsis. The other animals were examined and the transplants assessed clinically, microscopically, micro-angiographically and by scanning electron microscopy over a period of 48 weeks; finally they were submitted to biomechanical tests. Both techniques are suitable for transplantation but, over the period of observation, the lyophilised grafts remodelled completely. At the end, the mechanical resistance of the meniscus was identical in the two groups.

[Meniscus transplantation--animal experiment study]. / Die Meniskustransplantation--Tierexperimentelle Untersuchung.

The possibility of repairing meniscus lesions by transplantation was studied in 30 sheep. Grafting of the meniscus was performed in 15 animals each either with lyophilised homologous menisci that had been sterilised by gamma rays, or with deep frozen homologous menisci. 27 menisci could be evaluated over a period of 48 weeks. Besides the clinical, microscopical and scanning electron microscopical evaluation, the grafts were also examined microangiographically and biomechanically. Both lyophilised and deep-freeze menisci are suitable for transplantation, but the processes of transformation of the grafts are significantly different: Whereas complete transformation takes place in the lyophilised transplant during the study period of 48 weeks, the deep-frozen transplant is accepted and heals without any remarkable transformation process to full function. Although the biomechanical stress tests yielded good stress tolerance for both types of transplants, the deep frozen homologous menisci appear to be more favourable with regard to possible clinical aspects since they do not undergo any transformation.

[Meniscus transplantation and anterior cruciate ligament replacement--results 2-4 years postoperative]. / Meniskustransplantation und vorderer Kreuzbandersatz--Ergebnisse nach 2-4 Jahren postoperativ.

23 transplantations of meniscus combined with replacement of the anterior cruciate ligament were performed from May 1984 to December 1986 at the Department of Orthopaedics of the University of Munich ('Klinikum Grosshadern'). Clinical follow-ups were coupled with arthroscopic follow-ups on the average 10 months postoperatively in 19 patients with transplantation of the medial meniscus of the knee joint. In 17 cases a lyophilised meniscus was transplanted and in 6 cases a deep-freeze allogenous meniscus. There were no operation-specific complications in either group. Both the lyophilised meniscus transplants and the deep-frozen ones underwent a reduction in size during the observation period. Whereas good to excellent results were generally obtained with the deep-frozen transplants, the results seen in the lyophilised transplants were less satisfactory due to reduction in size partly down to regenerate size. The treatment results were of course positively influenced due to the contributory effect of the regained stability; in the patients with meniscus transplants the preoperative Lysholm score was 72 +/- 14 points, on the average 36 weeks postoperatively 82 +/- 15 points. However, clinical and arthroscopic findings showed that no clinically, immunologically and morphologically satisfactory meniscus replacement has become available to date.

Concentrations of ticarcillin and clavulanic acid in human bone after prophylactic administration of 5.2 g of timentin.

The penetration of ticarcillin and clavulanate into their distribution space within human bone was determined after prophylactic administration of 5.2 g of timentin (5 g of ticarcillin plus 0.2 g of clavulanic acid) to 20 patients undergoing hip surgery. All samples were taken 45 to 85 min postadministration. The mean concentrations of ticarcillin in spongiosa and corticalis bone were 57.1 and 70.5 mg/kg, respectively; those of clavulanic acid were 17.8 and 32.5 mg/kg, respectively. No infections occurred in these patients.

[Meniscus refixation and transplantation]. / Meniscusrefixation und -transplantation.

The knowledge we have about the biomechanical importance of the menisci of the knee joint makes it imperative, where possible, to treat their injuries by means of meniscus-conserving measures. Hence today meniscal suturing is performed successfully not only in fresh injuries but also in old baseline longitudinal tears, whether by means of the arthroscope or arthrotomy. Even after having removed the medial meniscus at a previous operation this can be replaced through homologous lyophilized or deep-frozen meniscal transplants, as would be applicable in cruciate ligament insufficiency of the knee joint. As such it may act as a mechanical protection, during the postoperative period, for an anterior cruciate ligament transplant.

Penetration of amoxycillin/clavulanate into human bone.

Twenty patients undergoing orthopaedic surgery for total hip replacement received a single prophylactic intravenous dose of 2.2 g Augmentin (2 g amoxycillin + 200 mg clavulanate). Bone samples removed during the operation were saved for amoxycillin and clavulanate assay. The proportion of inorganic matter in the bone samples was determined to calculate the concentrations of the drugs in their distribution volume. The cortical and cancellous bone were penetrated to a comparable extent by both compounds yielding maximum concentrations at one hour after the end of the infusion. The mean concentrations of amoxycillin in the cortex and spongy layer were 26.0 and 18.2 mg/kg within 1 h, 23.8 and 19.8 mg/kg in the interval from 1 to 2 h after infusion, and 9.2 and 5.9 mg/kg between 2 and 5 h. The corresponding values for clavulanate were 2.3 and 1.6 mg/kg, 2.5 and 1.6 mg/kg, and 1.0 and 0.7 mg/kg, respectively. No postoperative wound infections occurred in these patients.

Homologous meniscus transplantation. Experimental and clinical results.

The increase in severe ligament injuries of the knee has led to consideration of the need for meniscal transplantation in reconstructive operations for chronic rotational instability. Transplantation of the medial meniscus was carried out in two groups of 15 sheep. In one group lyophilised, gamma-sterilised allogenic menisci were transplanted and these underwent a complete remodelling in 48 weeks. In the other group, deep frozen allogenic menisci were used and these remained fully functional without remodelling. We then carried out meniscal transplantation in 22 patients who were followed-up for a mean of 14 months. Arthroscopy was possible in two-thirds of the cases at an average of 8 months after operation. Both types of transplanted menisci, lyophilised and deep frozen, decreased in size, as small as a regenerated meniscus in some cases. In general the deep frozen menisci showed better results.

[Enoxacin concentration in bone tissue]. / Enoxacin-Konzentrationen im Knochengewebe.

For successful treatment of bacterial osteomyelitis the administered antibiotic must reach sufficiently high concentrations in bone tissues. Therefore concentrations of enoxacin in bone in ten patients requiring hip surgery were measured. To prevent a postoperative infection, 400 mg enoxacin b.i.d. for two days were administered. On an average 120 (90-210) min after the final dose samples of venous blood and bone tissue were taken. The bone pieces were divided into corticalis and spongiosa. Using a bio-assay-method the following concentrations were found: (mean +/- S.D.): serum 2.88 ( +/- 0.90) mg/l, corticalis 5.90 ( +/- 0.79) mg/kg, spongiosa 3.95 ( +/- 1.01) mg/kg. Thus enoxacin reaches higher levels in bone tissue than in serum.