Introduction and Objectives: meniscal lesions in the avascular zone are difficult to heal because of the poor biological potential of the avascular tissue. Little is known about the molecular mechanisms that develop after a meniscal lesion in this low activity zone. The purpouse of this study is to determine the levels of gene expression of five different growth factors (IGF, IL-1β; TGF-β, PDGF-β and VEGF) in the first three weeks after a meniscal lesion in the avascular zone of rabbit menisci.

Materials and Methods: 28 white female New Zealand rabbits were used in this study. Through a small arthrotomy a 5mm longitudinal lesion was performed in the avascular zone of the anterior horn of the medial meniscus of each rabbit. The rabbits were sacrificed after 0, 1, 3, 7, 14 and 21 days (4 rabbits each). After sacrifice, the zone in which the meniscal lesion was performed was disected from the rest of the mensicus. It was then divided in two parts: a peripheric vascular zone and a central avascular zone. After ARNm extraction cuantitative PRC anaylisis with Sybergreen technology was performed using specific primers for each gene.

Results: There were significant expression increases of IGF, TGF-β and PDGF-β, in the vascular zone at two weeks but no variations of note in these genes in the avasacular zone. The expression of IL-1β is increased in the first day after injury in both zones but only last up to the thrid day in the vascular zone. There is an increase in VEGF expresion in the avascular zone at two weeks that is related to a symetric decrease in the vascular zone.

Introduction: tibial plateau fractures are a therapeutic challenge that are increasingly being dealt with arthroscopically assisted surgical treatment. About 40% of cases associate a meniscal lesion. Meniscal repair is a challenging technique in this setting but has an increased importance due to the intrinsic role as cartilage protector of the meniscus. Although suture in the course of the reconstructive procedure is more technically demanding and time consuming the biological surrounding of the repair is optimal (extensive intraarticular bleeding, prolonged non weight-bearing, presence of bone marrow elements, acute repair).

The objective of this study is to determine the outcomes of meniscal suture in this group of patients.

Material and methods: Between 1999 and 2007 sixty one tibial plateau fractures were operated with arthroscopic assistance in our institution. Of these, 25 presented meniscal injuries and 16 of these were repaired. Repair criteria were: no age limit was established and all types of ruptures (even radial or bird-beak lesions) were repaired if technically possible. 14 external menisci and 2 internal menisci were repaired. Morphologically 15 were longitudinal ruptures in the red-red zone and one was a bird beak rupture. Suture was performed using a combination of repair techniques including outside-inside (seven cases), inside-outside (two cases) and all-inside (14 cases). Functional results were evaluated with the following scales: Rasmussen, Honkonen, ICDK, Lysholm, SF-36 and Knee Society scores. Evaluation of the meniscal repair was performed either by M.R.I. of the knee (obtained in six cases) or arthroscopic revision of the meniscal repair (during surgery for implant removal in 9 cases). In one case the patient required a TKA not related to the meniscal lesion and the meniscus was revised during the procedure.

Results: All cases were available for follow up a minimum of 12 months after surgery (mean 2.6 +/−1.4 years). Functional results were excellent or good in 14 of 16 cases. One poor result was related to meniscal symptoms and requiered arthrocopic meniscectomy, the other poor result was due to arhtrofibrosis. Direct visual revision of the suture (either arthroscopically [9 cases] or during open surgery [one case]) allowed for the diagnosis the symptomatic failure of the repair and of complete healing in the rest of cases (9). MRI showed complete repair in four cases, partial repair in one and failure in one; all being asymptomatic.

Conclusions: this technique seems to offer good results with complete healing observed in 81% of cases and partial healing in 6%; symptomatic failure of the repair was observed only in 6% of the cases. In meniscal injuries related to this type of fracture, repair should be always considered as the biological environment seems to facilitate success in the repair.