Biomedical subjects
Publications and source records attributed to Yakup Yildirim.
The lateral meniscus tends to have more developmental variation than the medial counterpart. This is a report of an accessory discoid layer of lateral meniscus. All arthroscopic, magnetic resonance imaging and histopathological views are presented.
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.
BACKGROUND: Infection around an implanted orthopaedic device is a devastating complication, and the treatment of infections involving slime-forming bacteria is especially difficult. The purpose of the present study was to evaluate the effectiveness of a proteolytic enzyme, serratiopeptidase, in the eradication of a periprosthetic infection in an in vivo animal model. METHODS: In sixty Sprague-Dawley rats, the medullary canal of the right femur was drilled through the intercondylar notch and was inoculated with a Staphylococcus epidermidis strain (ATCC 35984) with a high slime-producing capacity. The cavity was filled with polymethylmethacrylate cement, and a Kirschner wire that had contact with the knee joint was inserted. None of the animals received any treatment for two weeks. Twenty rats were killed at two weeks after the inoculation in order to determine if the infection had become established. The remaining forty rats were randomized into two groups. One group received serratiopeptidase enzyme injections into the knee joint in addition to antibiotic therapy for four weeks, and the other group received intra-articular saline solution injections together with the same antibiotic therapy. The animals from both groups were killed two weeks after the end of therapy (on Day 56). The knee specimens were evaluated bacteriologically and histologically to determine the prevalence of persistent infection and the effects of the enzyme on local tissue. RESULTS: At two weeks, inoculated bacteria grew on culture of specimens from twelve (63.2%) of nineteen animals in the no-treatment group. Microbiological testing suggested that infection persisted in only one (5.6%) of eighteen animals in the serratiopeptidase-and-antibiotic group, whereas it was present in six (37.5%) of sixteen animals in the antibiotic-only group (p = 0.001). Histological evaluation showed similar results (kappa = 0.92). CONCLUSIONS: Serratiopeptidase was effective for eradicating infection caused by biofilm-forming bacteria in this experimental animal model. The antibiofilm property of the enzyme may enhance antibiotic efficacy in the treatment of staphylococcal infections.
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.
PURPOSE: Menisci are known to have receptors mainly concentrated at the anterior and posterior horns. Although they are purported to send afferent impulses to the central nervous system, this function has not been thoroughly evaluated. The purpose of the study was to investigate whether stimulation of the menisci initiates a cortical response. The reaction of the end organ to the reflex arc is also evaluated. TYPE OF STUDY: Prospective case series. METHODS: Fourteen patients with normal medial menisci were included in the study. Different parts of the knee joint (the posterior horn and the body of the medial meniscus, the medial femoral condyle, the capsule, and the joint space) were electrically stimulated by a probe during arthroscopy. The cortical response was monitored with somatosensory-evoked potentials (SEPs). The compound muscle action potentials (CMAPs) of the semimembranosus, quadriceps, and biceps femoris muscles were also monitored with electroneuromyography (ENMG). RESULTS: Among the stimulated parts, only the posterior horn of the meniscus produced cortical responses. No response was obtained with stimulation of the medial femoral condyle, the body of the medial meniscus, the capsule, or the joint space. Stimulation of the posterior horn of the medial meniscus produced a measurable amount of CMAP latency for the semimembranosus muscle, but not for the quadriceps and biceps femoris muscles. CONCLUSIONS: Stimulation of the posterior horn of the medial meniscus produces reproducible cortical SEPs and results in ENMG-verified response of the semimembranosus muscle where no response of the semimembranosus muscle is detected with stimulation of the other parts of the knee. CLINICAL RELEVANCE: The knowledge that only the horns of the medial meniscus have mechanoreceptors in the medial compartment of the knee helps to understand patients' signs and symptoms in medial compartment disease.
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.
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.
Several clinical and experimental reports have evaluated the spinal application of bioabsorbable material for plating the anterior lumbar and cervical spine, and in anterior and posterior lumbar interbody spinal fusion. Nevertheless, the use of these materials in posterolateral interlaminar fusion has yet to be elucidated in the literature. The effects of bioabsorbable self-reinforced polylactide rod (SR-PLLA) implantation, rigid fixation (K-wire) and non-implantation with posterior interlaminar fusion were compared using a rabbit model. Twenty-four mature domestic rabbits were divided into three groups. Eight received implantation with SR-PLLA, eight with K-wire, and eight were fused without instrumentation. The animals were killed at 12 weeks and evaluated by posteroanterior radiography, manual palpation and histological examination for the presence of fusion. Successful fusion was achieved in all of the animals in both implanted groups (SR-PLLA and K-wire), whereas solid fusion was not detected in any of the specimens in the non-implanted group. Computed tomography (CT) scans were used to detect fusion mass volume. The fusion mass in the SR-PLLA implanted group had a mean volume of 1,196 mm3 +/- 167 mm3 vs 1,061 mm3 +/- 181 mm3 for the K-wire implanted group (not significant) and 711 mm3 +/- 407 mm3 (p<0.05) for the non-implanted group. The results of this study suggest that the stabilization properties of both SR-PLLA rods and K-wire seem to be sufficient for spinal fusion, but using SR-PLLA is especially advantageous, since they do not require a removal operation and do not interfere with magnetic resonance imaging (MRI).
Foot and ankle injuries are most commonly encountered in athletes. Of these, pediatric and adolescent injuries have unique characteristics because of the distinct growth potentials and their consequences specific to this age group. In this article, foot and ankle injuries in child and adolescent athletes are reviewed in the light of the literature.
Thirty feet with hallux valgus (HV) having grade 2 and 3 sesamoid stations on AP radiographs were examined after Lindgren-Turan oblique distal metatarsal osteotomy with a minimum follow-up of 12 months. Adductor tendon release from the lateral sesamoid was not performed to determine the isolated effect of distal metatarsal osteotomy on metatarsosesamoidal reduction. Of the 30 feet, 20 (67%) had reduced and 10 (33%) unreduced sesamoids at the follow-up. Ultimately, distal metatarsal osteotomy (DMO) with lateral shifting of the first metatarsal head more than 7.2 mm was found to reduce the sesamoids in the great majority of the cases (95% CI 7.243-9.757). Sesamoid release is redundant for metatarsosesamoidal reduction if sufficient lateral shift of the first metatarsal head over the sesamoids is accomplished.
Forty-eight fresh frozen sheep Achilles tendons were used to compare the pull-out strengths of Kessler, Bunnell and locking loop techniques which are the standard configurations described for Achilles tendon repair. A simulated Achilles tendon rupture was done with a tenotomy made 2 cm proximal to the calcaneal insertion. One of the configurations was placed at the distal end of the proximal portion of the tendon specimens using No. 5 Ticron. The distal ends of the suture materials were left free and were not used to connect the proximal and distal portions of the tendon. Using a servohydraulic materials testing machine, each tendon was tested to failure in tension at a displacement rate of 20 mm/min. All the specimens failed due to pull-out of the suture material. Since the cause of failure was suture material breakage in the previous studies reporting repair strength, they were unable to represent the effect of configuration on the strength. This study is the first to represent the effect of configuration on the initial strength since there is no failure due to suture material breakage.
Superior excursion of the humeral head on the face of the glenoid was investigated to determine whether a relationship exists between the degree of humeral head excursion and the identity of the injured tendon in a shoulder with a torn rotator cuff. Twenty-seven patients with unilateral full-thickness rotator cuff tears diagnosed by either positive arthrogram or magnetic resonance imaging were included in this study. Three groups were formed based on intraoperative findings: 10 patients had isolated supraspinatus tendon tears (group 1), 11 patients had supraspinatus and infraspinatus tears (group 2), and 6 patients had supraspinatus, infraspinatus, and subscapularis tendon tears (group 3). There was no statistically significant difference between the degree of humeral head excursion in groups 1 and 2. However, patients in group 3 had a statistically significantly higher degree of excursion of the humeral head (P < .05) when compared with groups 1 and 2. In addition, an inverse relationship between the degree of humeral head excursion and preoperative Constant scores was found. Superior excursion of the humeral head on the glenoid had a significantly higher incidence in patients with subscapularis tears, and a larger amount of excursion was present in patients who had lower preoperative Constant scores.
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.
Congenital absence of the lateral sesamoid is an extremely rare condition. We present a case of congenital absence of the lateral sesamoid in which magnetic resonance imaging was performed. The literature is reviewed regarding the clinical significance of this anomaly.
A 19-year-old woman presented with pain at the lateral side of the fifth toe of her left foot, which was separated from the adjacent toe. Initial examination suggested dislocation of the fifth metatarsophalangeal joint due to a past fracture. Radiographs showed a mass arising from the proximal phalanx of the little toe, with no medullary and cortical continuity. Excisional biopsy of the mass was performed, and a histologic diagnosis of bizarre parosteal osteochondromatous proliferation of bone (Nora's lesion) was made.