Idiopathic anterior dislocation of the radial head: symptoms, radiographic findings, and management of 8 patients.

BACKGROUND: Radial head dislocation may occur during trauma or in association with congenital diseases, or it may be developmental or idiopathic. Reports of idiopathic dislocation of the radial head have been scarce. The symptoms, radiographic findings, and management of idiopathic dislocation of the radial head have not been well described in the literature. METHODS: During the past 28 years, we have encountered 8 cases of idiopathic anterior dislocation of the radial head (mean patient age, 12.5 years). In only 1 case did the patient and/or the patient's parents recall any preceding trauma or injury to the affected limb. Patients' complaints included a bulging mass, pain, and limited elbow flexion. Radiographically, the shape of the radial head was flat or slightly convex. Seven of the patients were treated with open reduction of the radial head and angulation osteotomy of the ulna. The other patient's radial head was stabilized without osteotomy. RESULTS: The mean postoperative follow-up period was 4.5 years. In patients whose elbow flexion was limited before surgery, improvement to more than 125° occurred. The bulging mass in the cubital fossa disappeared. None of the patients complained of disability during activities of daily living or sports participation. Radiographically, the radial head remained in the reduced position in all patients in whom open reduction of the radial head with angulation osteotomy of the ulna was performed. CONCLUSIONS: We have described the symptoms, radiographic characteristics, and treatment of idiopathic anterior dislocation of the radial head. Open reduction of the radial head combined with angulation osteotomy of the ulna yielded favorable results both clinically and radiographically.

Acute Compartment Syndrome of the Forearm Secondary to Hematoma after Playing Golf.

Acute compartment syndrome of the forearm secondary to hematoma without direct trauma has been reported rarely. We report a case of acute compartment syndrome of the forearm following a hematoma after playing golf. A 55-year-old man felt pain in his left forearm while playing golf that gradually worsened. He could not continue to play and visited the emergency department of our hospital. The radial side of his left forearm was markedly swollen on presentation, and he suffered severe pain that worsened with ulnar flexion of the wrist; no paralysis or hypesthesia was observed. A hematoma in the brachioradialis was seen on magnetic resonance imaging, and radial compartment pressure was 120 mmHg. A diagnosis of acute compartment syndrome was made, and urgent fasciotomy was performed. The patient recovered with no dysfunction of the arm.

Irreducible Dislocation of the Radial Head Associated With Pediatric Monteggia Lesions.

BACKGROUND: In pediatric patients with Monteggia lesions, the radial head can be reduced manually when displacement of the fractured ulna is corrected. Occasionally, however, a dislocated radial head could not be reduced manually even when the length and/or angulation of the fractured ulna had been corrected. We can find such cases in the literature, but those are single case reports. We encountered 17 cases of irreducible dislocation of the radial head in pediatric Monteggia lesions during the past 43 years. The purposes of this study were to identify the characteristics of our cases and to discuss the factors that inhibited reduction of the radial head. METHODS: Of 109 children treated for Monteggia lesions between 1972 and 2015, we encountered 17 cases of irreducible dislocation of the radial head. The patients' ages averaged 7.1 years, ranging from 2.6 to 12.1 years. Directions of the radial head dislocation were anterior in five cases, anteromedial in four, lateral in one, and anterolateral in seven. Most of the patients were referred to us from local orthopaedic clinics because of irreducibility of the radial head. We reduced the radial head surgically and confirmed the causes of irreducibility. RESULTS: In 10 of the 17 cases, the problem was identified as pseudoreduction. In those cases, the radial head was reduced in a supination position but redisplaced in a pronation position. Causes of irreducibility were traced to the annular ligament in 15 cases, biceps tendon in 1, and posterior interosseous nerve in 1. CONCLUSIONS: In cases of pediatric Monteggia lesions, we should pay attention to patients in whom the dislocated radial head is not reduced after closed reduction. The most frequent cause of hindered reduction was interposition of the annular ligament in the radiocapitellar joint. Here, the radial head seems to be reduced in the supination position but becomes redisplaced in the pronation position. After closed reduction, it is important to confirm whether the radial head is stable in both pronation and supination positions. LEVEL OF EVIDENCE: Diagnostic level IV.

A comparative study of the effects of bucillamine and salazosulfapyridine in the treatment of rheumatoid arthritis.

Bucillamine (Buc), developed in Japan, is a disease-modifying antirheumatic drug (DMARD) which has been used to treat numerous patients with rheumatoid arthritis (RA) in Japan and Korea with favorable results. However, it has not been used globally. In the present study, we compared the timing of onset of efficacy and the usefulness of this drug with that of the globally accepted agent salazosulfapyridine (SASP). There were 26 patients in the Buc group and 23 in the SASP group. We compared changes in the number of swollen joints, number of painful joints, duration of morning stiffness, grip strength, levels of inflammatory marker [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)], rheumatoid factor (RF), physician's rating by visual analogue scale (VAS), patient's rating of pain, patient's overall rating (VAS), and improvement according to European League against Rheumatism (EULAR) criteria (DAS28-CRP, DAS28-ESR) in these two groups of patients. Both Buc and SASP were shown to be efficacious within 3 months after the start of treatment. Both drugs were found to be suitable as first-line treatment of early RA. Signs of efficacy tended to occur earlier with Buc than with SASP, and Buc also tended to have higher efficacy than SASP.

Elbow valgus laxity may result in an overestimation of apparent shoulder external rotation during physical examination.

BACKGROUND: The contributions of the scapulothoracic articulation and spine when measuring shoulder range of motion have been well described; however, the effect of elbow valgus laxity has not. HYPOTHESIS: Increased elbow valgus laxity affects the assessment of shoulder external rotation measured during physical examination at 90 degrees of elbow flexion. STUDY DESIGN: Controlled laboratory study. METHODS: Seven cadaveric upper extremities were tested with an elbow valgus laxity-testing device. Shoulder external rotation was assessed with 2.8 N . m of external torque by measuring a change in the angle of the forearm axis at 90 degrees of elbow flexion. Elbow valgus laxity was measured in degrees of valgus angulation with 1.5 N . m of valgus torque with the humerus fixed. Shoulder external rotation and elbow valgus laxity were recorded at each of the following conditions: (1) intact, (2) after splitting the pronator muscles and venting the capsule, (3) after cutting the posterior band of the anterior oblique ligament of the ulnar collateral ligament, and (4) after cutting the anterior oblique ligament completely. RESULTS: After the posterior band of the anterior oblique ligament of the ulnar collateral ligament was cut, apparent shoulder external rotation and elbow valgus laxity were increased by 4.1 degrees +/- 1.7 degrees (P < .01) and 3.1 degrees +/- 1.3 degrees (P < .001), respectively, when compared with the intact condition. Complete cutting of the anterior oblique ligament resulted in an apparent increased shoulder external rotation and an increased elbow valgus laxity of 11.0 degrees +/- 1.1 degrees (P < .001) and 9.1 degrees +/- 1.2 degrees (P < .001), respectively, when compared with the intact condition. CONCLUSION: Shoulder external rotation as assessed by physical examination, which was defined as the angle of the forearm axis, as well as elbow valgus laxity, was significantly increased after the anterior oblique ligament of the ulnar collateral ligament was cut, although the glenohumeral joint condition was not changed. CLINICAL RELEVANCE: Elbow valgus laxity may cause an overestimation of shoulder external rotation on clinical examination of the shoulder.

Anatomy of ligamentous structures in the tarsal sinus and canal.

BACKGROUND: The descriptive morphology of the interosseous talocalcaneal ligament and other structures in the tarsal sinus and canal vary. An anatomical investigation of the ligamentous structures in the tarsal sinus and canal identified two distinct ligaments, the interosseous talocalcaneal ligament and the anterior capsular ligament, and three components of the medial root of the inferior extensor retinaculum. METHODS: Forty embalmed cadaver feet were examined. After disarticulation of the ankle joint, the posterior half of the talus was removed. The length, width, and thickness of the two ligaments and the three components of the extensor retinaculum in the tarsal canal and sinus were measured with calipers. Anatomical variations were recorded. RESULTS: The interosseous talocalcaneal ligament was band-like in 92.5% (38 of 40) of examined specimens, and the anterior capsular ligament was present in 95% (39 of 40) of specimens. The interosseous talocalcaneal ligament, the medial component of the inferior extensor retinaculum, and the talar component of the inferior extensor retinaculum had one or two distinct anatomical variations of morphology and attachments. The interosseous talocalcaneal ligament and the medial component of the extensor retinaculum formed a V shape in the tarsal sinus and canal. CONCLUSION AND CLINICAL RELEVANCE: We demonstrated the morphology and dimensions of the ligaments and components of the extensor retinaculum in the tarsal sinus and canal. Precise anatomy of the structures in the tarsal sinus and canal will strengthen our understanding of their function in the motion or stabilization of the subtalar joint. There may be a functional link between the medial component of the inferior extensor retinaculum and the interosseous talocalcaneal ligament.

Biomechanical comparison of different fixation methods on the tibial side in anterior cruciate ligament reconstruction: a biomechanical study in porcine tibial bone.

BACKGROUND: The fixation strength of the hamstring tendon graft on the tibial side is considered the weak point in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to compare the biomechanical characteristics of four types of ACL reconstruction methods on the tibial side. METHODS: Extensor digitorum tendons harvested from fresh bovine forelimbs were used as the graft materials in this study. Twenty-eight porcine tibias were divided into four groups based on different fixation methods. Group D was fixed using a double spike plate (DSP), group I was fixed using an interference screw, group DI-80 was fixed using both an interference screw and DSP (80 N tension was applied to DSP), and group DI-150 was fixed using both an interference screw and DSP (150 N tension was applied to DSP). RESULTS: The displacement of the grafts in response to 500 cycles of 0-150 N loading was significantly greater in groups D (10.3 +/- 15 mm) and I (5.5 +/- 1.7 mm) than that in groups DI-80 (2.1 +/- 0.3 mm) and DI-150 (1.2 +/- 0.4 mm), with no significant differences between groups DI-80 and DI-150. The ultimate failure load and stiffness were significantly higher in groups DI-80 (745 +/- 156 N, 103 +/- 17 N/mm) and DI-150 (801 +/- 129 N, 151 +/- 35 N/mm) than those in groups D (374 +/- 53 N, 70 +/- 13 N/mm), and I (520 +/- 76 N, 78 +/- 18 N/mm). The stiffness of group DI-150 was significantly greater than that of group DI-80. CONCLUSIONS: Our results indicate that the initial fixation strength of the hamstring tendon can be increased by using an interference screw combined with DSP on the tibial side.

Response of rabbit skeletal muscle to tibial lengthening.

BACKGROUND: Experimental and clinical studies have provided knowledge regarding osteogenesis during limb lengthening. However, response of skeletal muscle to limb lengthening is not fully understood, especially as concerns histogenesis. We studied the morphological response of rabbit skeletal muscle to limb lengthening. In this study, we investigated proliferation of satellite cells, responsible for generation of new myonuclei, during limb lengthening. METHODS: Tibialis anterior muscles of young and adult rabbits were subjected to lengthening at a rate of 0.5 mm twice per day for 20 days. After lengthening, muscle wet weight was measured to assess skeletal muscle growth, then proliferating cell nuclear antigen was measured. Immunostaining was performed to analyze proliferating cells in the proximal, middle, and distal portions of the muscle belly and the musculotendinous junction. RESULTS: Muscle wet weight increased significantly after lengthening both in adult (0.4 g) and young (0.1 g) rabbits. Satellite cells showed proliferation in response to lengthening. In adult rabbits, satellite cell proliferation increased along the entire lengthened muscle to a similar degree (from 7.1% in the middle portion to 8.6% in the musculotendinous junction). In young rabbits, proliferation was greater in the musculotendinous junction (4.8%) than that in other muscle portions (2.3% in the middle and distal portions, and 2.4% in the proximal portion). In adult rabbits, the rate of increase in satellite cell proliferation was 1780% in the middle portion to 2860% in the musculotendinous junction, whereas the rate was between 210% in the middle portion and 290% in the distal portion in young rabbit. The rate of increase in cell proliferation by lengthening was higher in adult muscle than that in young muscles as well as satellite cell proliferation. CONCLUSION: These findings indicate that limb lengthening promotes muscle growth in both young and adult rabbits.

Tarsal tunnel syndrome in athletes.

BACKGROUND: The details of the occurrence of tarsal tunnel syndrome in athletes have not been well documented in the literature, and more data on tarsal tunnel syndrome related to sporting activity are necessary to enable better recognition of this condition. HYPOTHESIS: Sporting activities make athletes vulnerable to the occurrence of tarsal tunnel syndrome under specific conditions. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1986 and 2002, 18 patients with tarsal tunnel syndrome related to sporting activities were surgically treated, of whom 15 patients (21 feet; mean age, 17.8 years) were competitive athletes and 3 were recreational sports amateurs (4 feet; mean age, 52.7 years). To assess the role of physical factors and sporting activities in making athletes vulnerable to the occurrence of tarsal tunnel syndrome, the authors reviewed the medical charts and evaluated the results of treatment. The mean duration of follow-up was 58.6 months. RESULTS: Activities that triggered tarsal tunnel syndrome were those that applied a heavy burden on the ankle joint such as sprinting, jumping, and performing ashibarai in judo under specific physical conditions. Predisposing underlying physical factors were flatfoot deformity and an existence of talocalcaneal coalition, accessory muscles, and bony fragments around the tarsal tunnel. The majority of patients were able to return to the same sport after treatment. CONCLUSION: Tarsal tunnel syndrome occurs in athletes involved in strenuous sporting activities, especially when predisposing physical factors are present.

Pathogenesis of tendinous xanthoma: histopathological study of the extremities of Watanabe heritable hyperlipidemic rabbits.

BACKGROUND: Tendinous xanthomas associated with heritable hyperlipidemia are clinically well known. Nevertheless, there have been few basic investigations of the pathogenesis of these xanthomas. To clarify the pathogenesis of these xanthomas, we examined the localization and histopathological features of xanthomatous tissues in the extremities of Watanabe heritable hyperlipidemic (WHHL) rabbits. METHODS: Twenty-six WHHL rabbits at 1-31 months of age were dissected to observe the localization of xanthomas. In the histopathological study, tendons and ligaments that included xanthomatous tissues were sectioned and stained with hematoxylin and eosin, Masson's trichrome, and toluidine blue. Immunohistochemical staining was performed with RAM-11, a monoclonal antibody specific for rabbit macrophages, and CD31, a monoclonal antibody specific for endothelial cells. RESULTS: At necropsy examination, spontaneous development of xanthomas was observed in the plantar side of the plantaris tendon, the flexor retinaculum of the carpus, and around the digital flexor tendons of each joint level. Xanthoma formation was observed from 10 months of age and progressed with advancing age. The histomorphological study revealed that xanthomas had developed in superficial paratenon of the tendons that wrap around bony or fibrous pulleys. Many fibrocartilage cells were observed in the deep side of affected tendons. A large number of blood vessels were seen in the xanthomatous tissues of these WHHL rabbits. Immunohistochemical evaluation revealed that the xanthoma plaques contained endothelial cells and macrophages. CONCLUSIONS: It is likely that mechanical stress and extensive vascularization are essential factors for xanthoma formation. Moreover, endothelial cells and macrophages cells are principal contributors to the pathogenesis of tendinous xanthomas and to atherogenesis.

Efficacy of rhBMP-2 during distraction osteogenesis.

BACKGROUND: Osteoinductive ability of bone morphogenetic protein-2 (BMP-2) has been studied in recent reports. In this study, we evaluated the efficacy of BMP-2 during distraction osteogenesis. METHODS: A group of 24 Japanese white rabbits were divided into four groups randomly and underwent lengthening of the right femur. Distraction was performed for 2 weeks (1.0 mm/day). Group A began distraction following a 7-day waiting period after surgery. For all other groups (B-D), distraction was started immediately after surgery. Groups A and B did not undergo any surgical intervention at the osteotomy site, as a control. The delivery system for rhBMP-2 used a polymer-coated gelatin sponge (PGS). Buffer/PGS was implanted into the osteotomy site in group C, and group D received rhBMP-2/PGS. Callus was evaluated radiographically at 1, 2, 4, and 6 weeks after the surgery, and all rabbits were killed at 6 weeks. One rabbit from each group was examined histologically; the remaining five rabbits underwent biomechanical testing. RESULTS: A significant increase in callus formation was evident in group D compared with that in other groups. In group D, regenerative changes were evident during the earlier phase. Formation of bone cortex and bone marrow cavity was almost complete in group D, and the cortex was thicker than that in the other groups. Torsional strength values (10(-2) Nm) of each group were as follows: A, 118.7 +/- 52.4; B, 160.0 +/- 40.7; C, 106.8 +/- 8.1; D, 266.1 +/- 93.1. Stiffness values (10(-3) Nm/degree) were as follows: A, 390.2 +/- 137.2; B, 391.8 +/- 158.4; C, 183.1 +/- 78.5; D, 624.4 +/- 214.2. Group D exhibited the highest values for both torsional strength and stiffness. CONCLUSIONS: Acceleration of the regenerative changes during the early phase occurred in the BMP-2-treated group. The efficacy of BMP-2 in distraction osteogenesis was recognized radiographically, histologically, and by biomechanical testing (torsional strength and stiffness).

Proximal metatarsal osteotomy: relation between 1- to greater than 3-years results.

UNLABELLED: We analyzed the relationship between the 1-year and greater than 3-years results of a distal soft tissue procedure with a proximal osteotomy for hallux valgus in the same patient population. The series consisted of 55 feet treated with this procedure. The results at 1 year and greater than 3 years were evaluated. The final followup was greater than 3 years. Patients with pain in the first metatarsophalangeal joint at the 1-year followup had a greater risk of having pain at the final followup than did patients without pain at the 1-year followup. Patients with metatarsalgia at the 1-year followup had a greater risk of having metatarsalgia at the final followup than did patients without metatarsalgia at the 1-year followup. The extension of the first metatarsophalangeal joint at the final followup was greater than extension at the 1-year followup. In 48 feet (87%), radiologic evaluation showed no or minimal changes in the hallux valgus and intermetatarsal angles between 1 year and greater than 3 years followup. The data suggest the 1-year results predict those beyond 3 years, although the extension of the first metatarsophalangeal joint may increase 1 year after surgery. LEVEL OF EVIDENCE: Prognostic study, Level III. See the Guidelines for Authors for a complete description of levels of evidence.

Type II SLAP lesions: a new scoring system--the sulcus score.

A new scoring system-the sulcus score-was developed to differentiate between a large superior labral sulcus and a type II superior labrum anterior-posterior (SLAP) lesion. The sulcus scoring system permits quantification of the size of the superior labral sulcus and the severity of a type II SLAP lesion. Specifically, the depth of the superior labral sulcus was classified into 4 grades, and the length was recorded by clock position. The sulcus score was then calculated by multiplying the depth (grade) by the length (the number of "hours" from the clock position). After stretching of the anterior capsule into excessive humeral external rotation at 60 degrees glenohumeral abduction, the sulcus score of cadaveric shoulders increased significantly (before, 3.4; after, 6.8), indicating the extension of the superior labral sulcus and resulting in a pathologically created type II SLAP lesion. The intraclass correlation coefficient and mean difference were 0.77 and 0.8 +/- 0.7, respectively, for intraobserver repeatability and 0.72 and 0.9 +/- 0.6, respectively, for interobserver reproducibility. The sulcus score provided a consistent and objective means for quantitatively describing the size and severity of type II SLAP lesions. Clinical assessment of the superior labral sulcus by use of the sulcus score may be useful for the diagnosis and treatment of type II SLAP lesions.

Efficacy of novel-concept pedicle screw fixation augmented with calcium phosphate cement in the osteoporotic spine.

Pedicle screw instrumentation has become increasingly popular for rigid internal stabilization of the thoracolumbar spine. However, when pedicle screws are used in elderly osteoporotic patients, the screw-bone interface is stripped easily. Therefore, the risk of screw loosening and backing-out after surgery has increased. The purpose of this study was to evaluate the efficacy of the novel-concept pedicle screw fixation augmented with calcium phosphate cement (CPC) in the osteoporotic spine. The novel-concept screw has the same shape as the ordinary screw, but it is hollow and fabricated with 20 small holes (1.3 mm in diameter) leading to the hollow part on the bottom of the thread. Fifteen embalmed cadaveric lumbar vertebrae were instrumented with two types of pedicle screw (the ordinary screw and the novel-concept screw) in each pedicle. Only the novel-concept screws were augmented with CPC after insertion. Seven days later, axial pull-out testing was performed at a crosshead speed of 10 mm/min. The mean maximal pull-out strength of the ordinary screws was 258 N, and that of the novel concept screws was 637 N. These results suggest that the novel-concept screw augmented with CPC can be useful for pedicle screw fixation of the osteoporotic spine.

Arthroscopic findings in chronic lateral ankle instability: do focal chondral lesions influence the results of ligament reconstruction?

BACKGROUND: There are few studies that have assessed the influence of focal chondral lesions on the results of ligament reconstruction for chronic lateral ankle instability. HYPOTHESIS: Focal chondral lesions do not influence the results of ligament reconstruction. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Arthroscopic examination of the ankle was performed on 30 consecutive patients immediately before ligament reconstruction using the palmaris longus tendon. Clinical assessment was performed using the Karlsson scoring scale. A radiologic assessment was performed on stress radiographs of the ankle. Preoperative anteroposterior and lateral weightbearing radiographs of the ankle did not show any joint space narrowing in any ankle. The mean duration of follow-up was 38 months. RESULTS: On arthroscopy, focal chondral lesions were found in 19 ankles (63%). Chondral lesions were located on the medial side of the tibial plafond in 13 ankles (43%), on the lateral side in 2 ankles (7%), on the lateral side of the talar dome in 3 ankles (10%), and on the medial side in 9 ankles (30%). Postoperative mean Karlsson scores in patients without chondral lesions and in those with chondral lesions were 99.1 and 98.4 points, respectively. Postoperative mean talar tilt angles in patients without chondral lesions and in those with chondral lesions were 5.9 degrees and 4.7 degrees , respectively. There were no significant differences in the clinical and radiologic results between patients with chondral lesions and those without chondral lesions. CONCLUSIONS: Reconstruction of the lateral ligament can be successful regardless of the presence of focal chondral lesions in patients with chronic lateral ankle instability when preoperative weightbearing radiographs of the ankle do not show any joint space narrowing.

Excessive humeral external rotation results in increased shoulder laxity.

BACKGROUND: The quantitative relationship between increased anterior shoulder laxity and increased humeral external rotation observed in throwers remains unclear. HYPOTHESIS: An elongated anterior capsule, especially the anterior band of the inferior glenohumeral ligament, produced by excessive humeral external rotation will result in increased anterior shoulder laxity and increased humeral external rotation. STUDY DESIGN: Controlled laboratory study. METHODS: Seven cadaveric shoulders were tested to measure the humeral rotational range of motion, glenohumeral translations, and length of the anterior band of the inferior glenohumeral ligament. Data were collected for the intact shoulders and after nondestructive stretching of 10%, 20%, and 30% beyond maximum humeral external rotation. RESULTS: Nondestructive excessive external rotational stretching resulted in a significant increase in superior (30%, 3.3 mm) and inferior (30%, 2.3 mm) length of the anterior band of the inferior glenohumeral ligament, external rotation (30%, 35 degrees), and anterior (30%, 2.4 mm), inferior (30%, 2.2 mm), and anterior-posterior (30%, 5.1 mm) translations. There were significant positive linear correlations between the length of the anterior band of the inferior glenohumeral ligament, external rotation, and anterior translation. CONCLUSIONS: Excessive humeral external rotation results in an elongation of the anterior band of the inferior glenohumeral ligament and an increase in anterior and inferior glenohumeral translations and humeral external rotation. CLINICAL RELEVANCE: Repetitive excessive humeral external rotation observed in throwers may be one of the biomechanical causes for increased shoulder laxity and increased humeral external rotation.

Biomechanical comparison of kyphoplasty with different bone cements.

STUDY DESIGN: Ex vivo biomechanical study. OBJECTIVES: To compare the biomechanical properties of isolated, fractured, osteoporotic vertebral bodies after treatment by kyphoplasty with one of two cements: alpha-tri-calcium phosphate cement (Biopex-R; Mitsubishi Materials Corp., Tokyo, Japan) or polymethylmethacrylate (Simplex P; Stryker-Howmedica-Osteonics, Mahwah, NJ). SUMMARY OF BACKGROUND DATA: Kyphoplasty and vertebroplasty typically use polymethylmethacrylate cements for the treatment of osteoporotic compression fractures. Scant information exists regarding the use of alternative cements in kyphoplasty. METHODS: Simulated compression fractures were created in 24 vertebral bodies (T6-T9, L2-L5) harvested from three female cadavers. Vertebral bodies were assigned to one of two groups: kyphoplasty with Biopex-R or kyphoplasty with Simplex P. The kyphoplasty treatment consisted of inserting bone tamps bipedicularly into each vertebral body, inflating the tamp, and filling the created void with Biopex-R or Simplex P. Pretreatment and post-treatment heights were measured, and the repaired vertebral bodies were recompressed to determine posttreatment strength and stiffness values. Differences were checked for significance (P < 0.05) using a repeated-measures analysis of variance followed by Tukey's test. RESULTS: Kyphoplasty with Biopex-R restored strength in the lumbar and thoracic vertebral bodies. Kyphoplasty with Simplex P displayed significantly greater posttreatment strength than initial strength in the thoracic region. Vertebral bodies augmented with either cement were significantly less stiff than their initial conditions, except for the thoracic vertebrae treated with Simplex P, in which stiffness was restored. There was no significant difference in percentage of height restored between the cement treatments. CONCLUSIONS: Kyphoplasty with either cement restored initial strength. In general, stiffness was not restored.

Ex vivo measurement of intravertebral pressure during vertebroplasty.

STUDY DESIGN: Ex vivo biomechanical study using cadaver vertebral bodies. OBJECTIVE.: To measure the increase in internal vertebral body pressure from cement injection during vertebroplasty. SUMMARY OF BACKGROUND DATA: Theoretically, the increased force required to inject polymerizing (viscous) cement into a vertebral body during vertebroplasty could produce a concomitant increase in intravertebral pressure and cause additional damage to the vertebral body. An alternative means of reducing intravertebral pressure during injection may be needed. METHODS: We placed 11-gauge cannulas bipedicularly in six vertebral bodies from each of two fresh female cadaver spines (one osteoporotic, one normal). One cannula served as the injection route; a manometer was connected to the other. After immersion of the spines in a saline bath, the vertebral bodies were injected with 10 mL of Simplex P cement by depressing the syringe plunger at a rate of 7 mm/sec using a materials testing machine. Static pressure was measured before and after injection. Peak pressure was measured during injection. Maximum pressure elevation was calculated as peak pressure minus initial static pressure. RESULTS: Maximum pressure elevation averaged (+/-SD) 9.4 +/- 8.5 mm Hg and 6.4 +/- 5.0 mm Hg in the osteoporotic and normal spines, respectively. In all cases (9 of 12) in which the pressure measurement system remained patent (i.e., not occluded by cement), postinjection pressure returned to the initial static pressure. CONCLUSION: The increase in intravertebral body pressure from cement injection during vertebroplasty is minimal. Alternative means of reducing intervertebral pressure before injection may not be needed.

Effect of suture repair on expression of beta1 integrin subunit in wounded rat patellar tendon.

Integrins play key roles in wound healing by mediating cell adhesion events. The purpose of this study was to determine how to change the expression level of the beta1 integrin subunit (integrin beta1) in the restoration of a tendon and to investigate the influence of suture on its expression. The lateral half of the patellar tendon in rats was transected. Half the rats were sutured immediately and the other half were left as they were. The rats were killed at 4, 7, 10, 14, 28, and 56 days postsurgery. Integrin beta1 expression in each harvested tendon was analyzed using immunohistochemistry and real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). Integrin beta1 was immunolocalized in fibroblasts adjacent to the wound and within the repair site itself. Although immunoreactivity for integrin beta1 in the unsutured group decreased on the tenth day, that in the sutured group continued to increase. In real-time quantitative RT-PCR, integrin beta1 mRNA expression level increased in both groups, but that in the unsutured group was higher than that in the sutured group. Our study indicates that suture influences the expression and mRNA level of integrin beta1, which is associated with tendon healing.