Calcification and ossification have been described in artery wall in pathologic conditions and aging. We previously described the use of cryopreserved arterial allografts as membranes for guiding bone regeneration. We hypothesize that artery is as good as synthetic membranes (e-PTFE, gold-standard in guided bone regeneration) due to the osteogenic potential of cells from its medial layer.

A comparative study was made creating 10 mm mid-diaphyseal radial defects in 15 New Zeland rabbits (30 forearms): 10 defects were covered with an e-PTFE membrane and 10 defects with no membrane (control group). Studies: X-rays, CT, MR, morpho-densitometric analysis, electronic and optical microscopy.

To demonstrate the cellular arterial stock, cryopre-served and fresh rabbit thoracic aorta specimens were studied. Medial layer was isolated and cultured as explants in normal medium. Cells were harvested and added to a 3-D scaffold based on plasmatic albumin in osteogenic medium. Immunocitochemical study was made. Radial defects surrounded by cryopreserved arterial membranes showed total regeneration in nine of 10 defects versus seven of 10 defects in e-PTFE group (no statistically significant differences were detected between them). No tissue layer was found between bone and artery while a connective tissue layer was observed between e-PTFE and bone. Neither radiological nor histological healing were detected in the control group.

Cells cultured had smooth muscle features as they showed immunofluorescence with anti-smooth muscle alpha-actin, anti-calponin and anti-vimentin antibodies. When cells were added to a 3-D matrix, they showed chondro and osteogenic differentiation, as they stained positive for types II and X collagen, alkaline phosphatase and von Kossa.

Although no statistically significant differences between artery and e-PTFE groups were detected, histological and cellular findings suggest a superiority of cryopreserved arterial allografts when compared with synthetic membranes of e-PTFE, with a contribution of the cellular stock of the medial layer in the healing process.

Purpose: To assess the safety and efficacy of using mini-incisions (? 10 cm) in the implantation of total hip prostheses.

Materials and methods: A prospective study was carried out to compare a cohort of 25 total hip prostheses implanted using a posterior approach through mini-incisions (mean length 9.4 cm, range: 8–10) with another 25-patient cohort where the incisions were of standard length. Patients in both groups had a similar gender distribution, similar ages (± 3 years), weight (± 3 kg) and height (± 3 cm). The type of implant used was also similar. Statistical analysis used: Chi-square, Mann-Whitney U test and Student’s t test.

Results: After 6 months, no significant differences were observed in the body mass index, femoral cortical index, intraoperative or postoperative complications, cup diameter, stem size, cup inclination, stem alignment, quality of femoral cementation, metaphyseal and isthmic filling of the stem, leg length discrepancy, number of blood units transfused, hemoglobin and hematocrite levels 6 hours post-op, in the decline of these levels from those of the preop period or in the Harris Hip Score values. The mini-incision group showed higher haemoglobin and hematocrite levels after 48 hours and a lower reduction of these values from preop to 48 hours after surgery and a lower suction drain. Fewer patients of these patients needed a transfusion, they were the first to sit and start walking and they had significantly shorter hospital stays. Mean follow-up was 20 months.

Conclusions: Total hip prostheses can be implanted through mini-incisions in a safe and reproducible way and lead to a better, faster recovery without additional complications, with the same degree of precision and similar clinical results.

Aims: Clinical and radiographic comparison between a fixed polyethylene prostheses and mobile bearing design. Methods: Prospective study in 147 tricompartimental cemented cruciate-retaining prostheses (Interax, Stryker- Howmedica-Osteonics): 90 conventional fixed polyethylene and 57 mobile bearing (antero-posterior slide and rotation over an axis in the medial plateau). No differences in preoperative age, sex, range of motion, deformity, rheumatoid arthritis or osteo-arthritis, and Ahlback stage. Results: At 1, 6, 12 and 24 months there were no differences between both groups (p> 0.05) in femorotibial angles, radiolucencies, duration of surgery, pain at rest or walking, stairs, arise from chair, walking ability, range of motion, supports (cane or crutches), complications and score of the American Knee Society. Conclusions: With 2-year follow-up there are no differences in clinical or radiographic results between fixed and mobile bearing knee prostheses. Further investigations with long-time follow-up are mandatory in order to determine differences and advantages in polyethylene wear or implant survival.

Aims: To determine whether the use of Biphasic Calcium Phosphate (BCP) plus local autogenous graft modifies our clinical results and fusion rate, in comparison with iliac crest graft alone. Methods: Prospective and nonrandomized study. 40 patients were operated on with pedicle instrumentation and posterolateral fusion. Degenerative lumbar disease was the etiology. 25 patients had one level fusion and 15 two or more. Minimum follow-up: 1 year. 15 patients were smokers (17.4 cig/day). The Oswestry disability index at 0, 3, 6 and 12 months was filled in to see the evolution and final clinical result. To evaluate the fusion, X-ray criteria were used. Results: Oswestry test changed from 63,8 to 16,4 at the end of the study. 3 patients did not achieve fusion (7,5%), none of them smokers. Up to date we have been working with the same idea but trying to increase the fusion rate by adding bone marrow to BCP and grafts. The initial results are very encouraging. Conclusions: We have no difference in our non-union rate between previous historic register and the new technique.

Similar clinical results were obtained but the proportion of excellent/good has improved with iliac crest preservation.

Aims: Clinical and radiographic evaluation of retinacular lateral releases using an arthroscopic approach, for anterior knee pain in cases with slight patelar axial malposition Methods: Prospective study in 34 patients. Evaluation according to the Insall clinical score, patient opinion, and change in radiographic angles and index from pre-operative to post-operative. Results: Postoperative clinical score (Insall 1983): 82% excellent; 6% good; 6% poor; 6% bad. Angular values: patelar index (Cross 1976) of 7,1 and sulcus angle (Brattstrom 1964) of 139,6∞. Radiographic correction: from 15,7 to 17,9 in patello-femoral angle (Laurin 1978); from −5,6 to −5,3∞ in congruency angle (Merchant 1974); and from 1,37 to 1,12 in patello-femoral index (Laurin 1978). Conclusions: Clinical results, patient satisfaction, and radiographic correction of congruency angle, patello-femoral angle and patello-femoral index make justifiable the use of arthroscopic lateral releases in the treatment of selected cases of patello-femoral pain.