Dimitrios N. Lyras

The Influence of Platelet-Rich Plasma on Angiogenesis During the Early Phase of Tendon Healing

Background: The poor vascularity of tendons is a major factor in their limited healing capacity. The aim of this study was to assess the effect of Platelet Rich Plasma (PRP) on angiogenesis during tendon healing. Materials and Methods: Forty-eight skeletally mature New Zealand White rabbits were used. The Achilles tendon was transected transversely and 0.5 ml of PRP was injected into the tendon mass on each side of the incision on both limbs. The injection in the control group consisted of saline. Six animals from each group (12 tendons each) were sacrificed after 1, 2, 3, and 4 weeks following treatment. Three sections from each Achilles were stained with hematoxylinosin for microscopic examination. Further three sections were immunostained with a monoclonal antibody against CD31 (Daco Co), followed by image analysis to count new vessel numbers and statistical analysis was performed. Results: There was significantly more angiogenesis in the PRP group compared to the control group during the first two weeks of the healing process, i.e., inflammatory and proliferative phase (p < 0.0001). The orientation of collagen fibers in the PRP group was better organized. The number of the newly formed vessels in the PRP group were significantly reduced at 4 weeks compared to the controls (p < 0.0001) suggesting the healing process was shortened. Conclusion: PRP seems to enhance neovascularization which may accelerate the healing process and promote scar tissue of better histological quality. Clinical Relevance: Although these results need replication and further biomechanical research, PRP may promote tendon healing acceleration.

Application of PRP gel alone or in combination with guided bone regeneration does not enhance bone healing process: An experimental study in rabbits

INTRODUCTION The aim of this study was to assess the hypothesis that application of platelet-rich plasma (PRP) gel in mandibular defects in rabbits, alone or in combination with guided bone regeneration (GBR) techniques, could enhance the bone healing process. MATERIALS AND METHODS Thirty New Zealand white rabbits were used. Three groups of 10 animals each were assigned, and the animals were sacrificed after 12 weeks. During the operation, a rotating trephine bur was used to create circular defects 10-mm in diameter in the region anterior to the jaw angles. In group human fascia lata (HFL), a human fascia lata membrane was used. In group PRP, PRP gel was used to fill the defect, and in group HFL+PRP, PRP was used to fill the defect which after that was covered with a human fascia lata membrane. RESULTS In general, none of the control sides and the PRP treated sides had full development of bone or filling of the defect through bone bridging. Conversely, the sides on which the fascia lata membrane or the combination of membrane and PRP had been applied were characterized mostly by development of newly formed bone that bridged the gap. CONCLUSIONS Our results suggest that the application of PRP gel alone or in combination with GBR does not enhance bone healing process.

Temporal and spatial expression of TGF-β1 in an Achilles tendon section model after application of platelet-rich plasma

BACKGROUND To investigate the effect of platelet-rich plasma (PRP) on TGF-beta1 expression during tendon healing. METHODS We used 48 skeletally mature New Zealand White rabbits. 24 rabbits received the PRP, and 24 rabbits served as an untreated control group. Equal numbers of animals were sacrificed at 1st, 2nd, 3rd, and 4th week. The surgical procedure involved a transverse incision to transect the Achilles tendon. A volume of 1ml of PRP was then injected into the tendon mass in the PRP group. Histological and immunohistochemical evaluations with an anti-TGF-beta primary antibody were performed. RESULTS The pattern of expression of TGF-beta1 in the PRP group was characterized by a significant upregulation during the first 2 weeks and subsequently significant downregulation in the 3rd and 4th week in comparison with the controls. CONCLUSIONS Our results suggest that PRP may affect the tendon healing process by altering the expression of TGF-beta1.

A humeral shaft fracture complicated with anterior shoulder dislocation in a young male treated with modified Intramedullary nailing prior to reduction: a case report

IntroductionAnterior dislocation of the shoulder joint with an ipsilateral fracture of the humeral shaft is a rare injury which may require demanding technical skills.Case presentationA 33 years old male sustained a work accident. Radiographs showed an anterior dislocation of the shoulder with a transverse fracture of the middle third of the humeral shaft on the same side. The dislocation proved to be irreducible in the setting of the fracture humerus. Thus, stabilization of the shaft fracture was successfully applied with an intramedullary nail and a small antirotational plate prior to the reduction. The patient recovered full function of the shoulder.ConclusionPerforming primary intramedullary nailing of the humeral shaft fracture before manipulation of the joint resulted to an excellent outcome.

Long-term Results of Mitchell's Procedure for Hallux Valgus Deformity: A 5- to 20-year Followup in 204 Cases

Background: There are limited studies on the long term outcome of Mitchells osteotomy for hallux valgus deformity. We present the long term results of 204 cases. Materials and Methods: Postoperative clinical and radiological evaluation with a mean follow up of 12.9 years was performed on patients with preoperative hallux valgus angles (HVA) of up to 50 degrees and intermetatarsal angles (IMA) of up to 20 degrees. Two crossed Kirschner wires were used to fix the capital fragment; lateral soft tissue release performed when deemed necessary. Comparisons were made between the pre- and postoperative measurements using a Mann-Whitney U-test. Statistical significance was defined at p < 0.05. Results: The mean AOFAS score improved from 49.6 to 87.9 points (p = 0.004). There was significant improvement in the HVA and IMA, 33.8 degrees versus 16.1 degrees (p = 0.002) and 15.2 degrees versus 8.2 degrees (p = 0.004), respectively. Fifty-seven cases (27.9%) had preoperative HVA greater than 40 degrees but only 16 required lateral soft tissue release with no significant difference in the postoperative HVA (21.3 versus 20.8, p = 0.08). There was a significant change in lateral metatarsalgia and symptomatic callosities (18.3% versus 11.8%, p = 0.023). In 97.6% of cases the patients were satisfied with the overall result. Revision surgery was performed in five cases (2.5%). Conclusion: Mitchells osteotomy was a reliable technique with successful outcome and low complication rate when performed with Kirschner wire fixation and lateral soft tissue release when appropriate. It may also be successfully performed with hallux valgus angles greater than 40 degrees. Level of Evidence: IV, Retrospective Case Series

Results of Extra-Articular Subtalar Arthrodesis in Children with Cerebral Palsy

Background: Grice-Green extra-articular subtalar arthrodesis is considered to be a valid surgical method which improves foot alignment in patients with spastic pes planovalgus deformity. The purpose of the present study was to examine the long-term results of Grice-Green procedure and whether it can achieve significant correction of each of the components of pes planovalgus deformity. Methods: Eleven children (16 feet) with cerebral palsy who underwent Grice extra-articular subtalar arthrodesis were reviewed retrospectively. The mean age of patients at the time of surgery was 9 years and 8 months (range, 6 years 5 months to 12 years 4 months). The mean followup was 3 years and 7 months (range, 2 years 1 month to 8 years 3 months). Seven radiographic parameters of each patient before surgery, after surgery and at the latest followup were used. In addition, position of the graft relative to the weightbearing axis of the tibia was evaluated. Results: Most of the examined parameters showed statistically significant correction which was maintained in the long run. Moreover, the placement of the graft along the mechanical axis seemed to play an important role for stability and preservation of correction of the planovalgus deformity. On the other hand, there were three cases where the osseous graft was absorbed and two cases where triple arthrodesis was necessary due to recurrence of the deformity. Conclusion: Grice-Green extra-articular subtalar arthrodesis improves foot alignment in patients with spastic pes planovalgus deformity and can achieve significant correction, postoperatively as well as on a long-term basis, of each of the components of pes planovalgus deformity. Level of Evidence: IV, Retrospective Case Series

Restoration of the Mechanical Axis in Total Knee Artrhoplasty Using Patient-Matched Technology Cutting Blocks. A Retrospective Study of 132 Cases

Background The aim of this study is to evaluate the accuracy of bone cuts and the resultant alignment, using the MyKnee patient specific cutting blocks. Methods We retrospectively reviewed 132 patients undergoing primary TKR for osteoarthritis by one single surgeon. The operative time, the preoperative Hip-Knee-Ankle (HKA) axis based on the CT-scan, the postoperative HKA axis based on long axis standing x-rays, the planned and the actual size of the femoral and the tibial components, and the number of the recuts which has been made intraoperative were measured. Results The average preoperative HKA axis was 177.50 (range 163.50 to 1940), whereas the average postoperative HKA axis was 179.40 (range 177.10 to 182.70). No outliers were reported in the study (0%). Intraoperatively, 4 femoral components (3.03%), and 7 tibial components (5.30%) applied to the patients were different than the planned size. There was no need of recuts in any of our cases intraoperatively. Conclusion The MyKnee system evaluated in this study was shown to be remarkable reliable in the coronal plane alignment, and the prediction of the component size. However, further studies are needed to determine whether there are any clinically important improvements in outcomes or patient satisfaction when using patient-specific cutting blocks for TKA.