The effect of therapeutic ultrasound on metallic implants: a study in rats.

OBJECTIVE: To investigate whether therapeutic ultrasound (US) use over metallic implants has the potential for adverse effects as a result of greater temperature increases at the tissue-metal interface. DESIGN: A randomized controlled trial. SETTING: A research laboratory. ANIMALS: Sprague-Dawley rats (N=40; weight, 230-300g) were used and divided into 3 study groups. INTERVENTIONS: In group 1, both limbs of 10 rats were used for evaluation of temperature changes. Metal pins were placed into the femur of the left limb, and the right limbs were used as controls. A thermal sensor was placed into the medulla to record the elevation of tissue temperature during US application. In groups 2 and 3 with 15 rats in each, a midshaft femoral fracture was produced, and intramedullary fixation was performed with metal pins. Group 2 received US treatment for 5 minutes daily and continued for 27 days. Group 3 served as controls. MAIN OUTCOME MEASURES: The rats in groups 2 and 3 were killed on postoperative day 30. The specimens were evaluated by radiology, histopathology, and biomechanics. RESULTS: The presence of metal in bone did not cause an increased temperature rise. US application did not increase or decrease callus formation, and there was no tissue necrosis. The average removal torques of pins in groups did not show a significant difference. CONCLUSIONS: Internal fixation with metallic implants may not be a contraindication for therapeutic US treatment.

Effect of partial medial meniscectomy on the proprioceptive function of the knee.

INTRODUCTION: The aim of this study was to assess the proprioception of the partial meniscectomized knee and to assess if there is an effect on the knee proprioception. MATERIALS AND METHODS: We performed a case-control study involving patients with meniscus tear at the posterior horn of medial meniscus. Group 1 composed of 19 patients, with an average age of 26.3 years, who were enrolled after sustaining an injury to the medial meniscus. Twenty healthy individuals, with an average age of 25.1, without history of knee injury, constituted Group 2. In order to document the proprioceptive capabilities of the knee, angle reproduction tests were performed. RESULTS: At a mean of 2 years after the surgery, there was no difference between the meniscectomized and healthy knee regarding the angle deviations in the lower flexion angles (15 degrees , 30 degrees , 45 degrees ). However, mean knee joint position sense (KJPS) at 60 degrees reproduction in Group 1 and 2 was 64.3 (SD 5.3) and 69.2 (SD 4.9), respectively. Concomitantly, mean KJPS at 75 degrees reproduction in Group 1 and 2 were 80.1 (SD 6.59) and 74.4 (SD 5.6), respectively. Paired t test showed a statistically significant difference between Group 1 and 2 when compared to control angle deviations at 60 degrees and 75 degrees reproductions (P < 0.05). CONCLUSION: KJPS of the patients in meniscectomized group was poorer than the patients in healthy knee group at 60 degrees and 75 degrees knee flexion degrees. Those results indicated that even a partial absence of menisci causes a deterioration of proprioceptive functions of the knee.

The effect of dehydration and irrigation on the healing of Achilles tendon: an experimental study.

BACKGROUND: Air exposure is a factor that inhibits in vitro cellular proliferation and matrix synthesis in tendons. Aim of this experimental study was to evaluate effect of dehydration and irrigation on healing of Achilles tendon. METHODS: Achilles tenotomy was done in forty-five Sprague-Dawley rats. In control group, tendon was sutured immediately. In the remaining two groups, the Achilles tendons were allowed to direct exposure of air. Irrigation of Achilles tendon was performed in one of exposed groups, while irrigation was not done in other group. After 60 minutes, tendons of both groups were sutured same as control group. Rats were sacrificed at postoperative day 28. Achilles tendons were dissected and histological and biomechanical evaluations were performed. RESULTS: Histological evaluation revealed intense fibrosis formation with adhesion of tendon to surrounding tissues in the air exposed groups. The quantity of angiogenesis and inflammatory reaction were also higher in experimental groups regardless of irrigation. Air exposed tendons had higher tensile strength however lower stiffness than control group in biomechanical evaluation. CONCLUSION: Air exposure decreases quality of healing by increasing fibrosis and adherence formation. These negative effects of exposure to air were not counteracted by irrigation. However, air exposure didn't affect tensile strength of the healing.

Components of the Wilson osteotomy that are effective on hallux valgus repair.

Wilson osteotomy of the first metatarsal is a technically simple and reliable operation for the correction of the hallux valgus (HV) deformity. The major anatomic components of the osteotomy are the osteotomy angle and the distance of the osteotomy to the first metatarsophalangeal (MTP) joint. Lateralization of the first metatarsal head is the rationale for correction of the deformity. The main disadvantage of the technique is the considerable shortening of the first metatarsal. The relation between the amount of HV correction, first metatarsal shortening, and the anatomic parameters of the osteotomy was evaluated. Radiographs of 46 feet of 32 patients were retrospectively evaluated after an average follow-up period of 31.4 months. From the preoperative, early postoperative, and last control radiographs, the amount of HV correction, first metatarsal shortening, the osteotomy angle, the distance of the osteotomy to the first MTP joint, and lateralization of the first metatarsal head were measured. The presented study indicated that the osteotomy angle and the lateral displacement of the metatarsal head have a significant correlation with the amount of HV correction. Distance of the osteotomy to the first MTP joint has no relevance with the repair of the deformity. A positive linear correlation was present between the osteotomy angle and the first metatarsal shortening. Because the amount of first metatarsal shortening has significant influence over the clinical result, the main aim in a Wilson osteotomy should be maximum lateral displacement of the metatarsal head with a minimum osteotomy angle.

[Tendon holding capacities of the suture materials used in repairing Achilles tendon rupture]. / Asil tendonu tamirinde kullanilan dikis materyallerinin tendonu tutma kapasiteleri.

OBJECTIVES: We evaluated tendon holding capacities of suture materials that are commonly used in repair of Achilles tendon ruptures. METHODS: Achilles tendons of 60 sheep were removed by incisions 2-cm proximal to the calcaneal insertion and 1-cm distal to the musculotendinous junction. The tendons were randomly divided into six groups and sutures were placed with the Kessler technique at the distal end of the tendons using one of the following suture materials: 2 polydioxanone (PDS), 1 PDS, 2 Vicryl, 1 Vicryl, 2 Ethibond, and 1 Prolene. The distal end of the suture material was left free. Each specimen was mounted in an Instron machine, with the tendon being placed proximally and the suture material distally. The system was loaded with a displacement rate of 20 mm/min. RESULTS: Failure of all the specimens was due to pull-out of the suture material through the tendon. There were no failures due to suture breakage. The highest and the lowest tendon holding capacities were found with 2 PDS and 2 Ethibond sutures, respectively. CONCLUSION: Following Achilles tendon repair, the healing period, in particular the first three weeks, is precarious for pull-out of the suture material through the tendon. Thus, tendon holding capacity of the suture material is an important factor for the strength of the repair. Among the tested suture materials, 2 PDS was found to have the highest tendon holding capacity.

Suture holding capacity of the Achilles tendon during the healing period: an in vivo experimental study in rabbits.

BACKGROUND: Early motion and weightbearing is known to promote the healing of Achilles tendon repair. It is important to be informed about the repair strength for a secure rehabilitation. There are reports about the initial repair strength of Achilles tendons; however, they are mainly in vitro studies that represent the time zero strength of the repair. Softening of the tendon observed during the biological process of the tendon healing, which may effect the suture holding capacity and in turn the repair strength of the tendon has not been evaluated before. METHODS: In the current study, the suture holding capacity of rabbit Achilles tendon was observed at various times during the healing period. RESULTS: The suture holding capacity of the tendon at the end of the first and third weeks after surgery was found to be similar within 30% of the control tendon. However, at the end of the fourth week it was doubled reaching 65% of the control tendon. CONCLUSIONS: Intrinsic tendon insufficiency which causes a decrease in the suture holding capacity of the tendon may lead to pull-out of the suture material during the postoperative third week. This period is precarious for early motion and weightbearing since the suture holding capacity of the tendon doubled relative to the previous three weeks.

Effect of metatarsophalangeal joint position on the reliability of the tangential sesamoid view in determining sesamoid position.

BACKGROUND: Lateral displacement of the sesamoids of the first toe relative to the metatarsal head is a common finding in hallux valgus deformity. Several methods have been described for quantifying the amount of subluxation from anteroposterior radiographs but a tangential sesamoid radiograph has been determined to be the best view to evaluate sesamoid displacement. METHOD: We evaluated the sesamoid position at different angles of the first metatarsophalangeal (MTP) joint to determine the effect of first MTP joint dorsiflexion on sesamoid position when tangential sesamoid view radiographs are made. Sesamoid positions of 22 feet with hallux valgus were graded from the short axis computed tomography (CT) images obtained with the MTP joint in 0, 35, and 70 degrees of dorsiflexion. RESULTS: Approximation of the sesamoids to reduction was apparent as dorsiflexion of the first MTP joint increased. CONCLUSION: Different dorsiflexion degrees of the first MTP joint when tangential sesamoid radiographs are made modulate the position of the sesamoids and may lead to misclassification on grading.

Effect of sagittal plane deformity of the lumbar spine on epidural fibrosis formation after laminectomy: an experimental study in the rat.

STUDY DESIGN: An animal model of postlaminectomy lumbar column sagittal plane deformity was designed in rats. OBJECTIVES: To analyze the effect of lumbar column deformity (lordosis and kyphosis) on postlaminectomy epidural fibrosis formation. SUMMARY OF BACKGROUND DATA: Incidence of peridural fibrosis formation after lumbar spinal surgery is considerably high. Instability and sagittal plane deformity of the lumbar spine has been implicated (not proven) as the factors for the development of epidural fibrosis. The effect of traction (kyphosis) or relaxation (lordosis) of the lumbar spine on epidural fibrosis formation is not known. METHODS: L4 laminectomies were performed in 30 rats. Three equal groups were formed. In the control group (group I), only laminectomy was performed. In other groups after laminectomy, lumbar lordosis (group II) and kyphosis (group III) was maintained with steel implants. The scar formation was evaluated both histologically and histomorphometrically on the 12th postoperative week. RESULTS: Kyphosis developed in group I. The mean amount of peridural scar tissue was significantly more evident in groups I and III than the lordosis group. The extent of adherence to the dura mater and the nerve roots was most apparent in group III. CONCLUSIONS: Kyphosis and consequent traction of the lumbar spine is one of the causes for increased epidural fibrosis formation after laminectomy. On the contrary, establishment of lordosis and relaxation of the lumbar spine decreased the scar tissue formation in rats.

[The injection of acrylic bone cement prevents bone collapse in the intercalar bones lacking bony support: an experimental sheep semilunar bone model]. / Akrilik kemik çimentosu enjeksiyonu kemik doku destegini yitirmis interkalar kemiklerde olusan çökmeyi önleyebilir.

OBJECTIVES: In a sheep semilunar bone model, we investigated whether collapse in the intercalar bones lacking bony support could be prevented by the injection of acrylic bone cement. METHODS: The study included 16 limbs of eight sheep. Preoperatively, anteroposterior and lateral views of the carpal joints in the fore limbs were obtained. The animals were divided into four groups. In group 1 (n=3) no surgical procedure was performed in the right semilunar bones, whereas the periosteum on the contralateral side was elevated (group 2; n=3). The first two groups were left as controls. In Group 3 (n=5) the left semilunar bones were filled with acrylic bone cement following decancellation of the bone, while the right semilunar bones were left decancellated (group 4; n=5). The sheep were monitored for three months. Radiographs of the carpal joints were obtained to evaluate collapse occurrence in the semilunar bones. Thereafter, the animals were sacrificed and the semilunar bones were excised for biomechanical and histological examinations. Osteonecrosis and cartilage damage were sought and resistance to compressive forces was investigated. RESULTS: Radiologically, the extent of collapse was statistically significant in the semilunar bones in group 4 (p<0.05). The use of acrylic bone cement was found to prevent collapse in group 3, with no significant difference being noted between preoperative and postoperative semilunar bone heights (p>0.05). Biomechanically, the least resistance to compressive forces was measured in group 4 (p<0.05). Histologically, cartilage damage and osteonecrosis were only seen in group 4. CONCLUSION: Our data suggest that the use of acrylic bone cement prevents collapse in the semilunar bones, without inducing any cartilage damage or osteonecrosis.