Maximum loading of carpal bones during movements: a finite element study.

BACKGROUND: Maximum stresses show critical points on an object because failure may start from the area close to maximum stress points. However, there appears no study on maximum loading points of carpal bones. PURPOSE: To clarify the loading pattern of each carpal bone during wrist movements. METHODS: A finite element wrist model was designed using a three-dimensional reconstruction of computed tomographic images from the distal end of radius and ulna to the proximal third of metacarpals. Loading was performed in neutral, 45° of flexion and extension, 5° of radial and 25° of ulnar deviation, and maximum loading points were plotted. RESULTS: In each position except for extension, minimum loads were carried by triquetrum, while minimum loads were carried by capitatum in extension. Maximum loads were carried by trapezium in neutral and ulnar deviation and flexion but by scaphoideum in radial deviation and extension. CONCLUSION: Studies on maximum loading of each bone are a new approach and may help to improve the knowledge on wrist mechanics.

Load transmission characteristics of limited carpal fusions: a two-dimensional finite element study.

Although limited carpal fusion is a choice of treatment in several wrist disorders, little is known about the biomechanics of these procedures, especially the loads carried by the ligaments. In a finite element study, four types of limited carpal fusions (scaphotrapeziotrapezoid, capitohamate, four corner fusion with and without scaphoid excision) were simulated and the loads carried by the ligaments were recorded. Measurements were repeated with and without implantation. The load transmission through the ligaments varied by the type of the fusion but, radioscaphoid and long radiolunate ligaments carried significantly more loads if not excised during the operation. Implantation did not affect the results in most cases. The model of the present study may be useful in preoperative planning.

Intra-articular hyaluronic acid compared to exercise therapy in osteoarthritis of the ankle. A prospective randomized trial with long-term follow-up.

OBJECTIVE: The goal of this study has been to determine whether hyaluronic acid (HA) or exercise therapy can improve functional parameters in patients with osteoarthritis (OA) of the ankle. METHODS: In a prospective clinical trial, 43 ankles (30 patients) with radiographic Kellgren Lawrence grade III OA were randomized to receive three intra-articular HA injections, with one-week interval of or exercise therapy for six weeks. Patients were evaluated by the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale and followed-up after 12 months. RESULTS: Total AOFAS Ankle-Hindfoot score of OA patients has improved in both groups, varying from 61.6+/-16.8 to 90.1+/-9.7 with HA treatment and from 72.1+/-16.6 to 87.5+/-17.5 using exercise therapy at the end of the trial (p<0.01). There were no statistically significant differences between the groups. CONCLUSION: This prospective randomized trial confirmed that, both HA injections and exercise therapy provide functional improvement. However, larger trials with longer follow-up are necessary for more definite conclusions.

Normal range of motion of the joints of the upper extremity in male subjects, with special reference to side.

We measured, with a universal full-circle manual goniometer, the active and passive arcs of motion of the shoulder, elbow, forearm, and wrist in 1000 healthy male subjects who were right-hand dominant and who ranged in age from eighteen to twenty-two years. The ranges of motion on the right side were significantly smaller than those on the left. We concluded that the contralateral, normal side may not always be a reliable control in the evaluation of restriction of motion of a joint.

Lengthening of congenital below-elbow amputation stumps by the Ilizarov technique.

Patients with short congenital amputations below the elbow often function as if they have had a disarticulation of the elbow. We have reviewed the results in six patients who had lengthening of such stumps by the Ilizarov technique to improve the fitting of prostheses. The mean lengthening was 5.6 cm (3.4 to 8.4), and in two patients flexion contractures of the elbows were corrected simultaneously. Additional lateral distraction was used in one patient to provide a better surface on the stump. There were no major complications. All six patients were able to use their prosthesis at the latest follow-up after 39 to 78 months.

A new technique of talectomy for severe fracture-dislocation of the talus.

We report a new technique of talectomy for patients with Hawkins group III fracture-dislocation of the talus. Talectomy is performed through a medial incision, the foot is displaced anteriorly, and the fractured or osteotomised medial malleolus is moved laterally and fixed to the tibia with a malleolar screw. Full weight-bearing is allowed after six weeks. In four patients at 36 to 57 months after operation the results were excellent in three and good in one, with no pain or early evidence of degenerative arthritis in the remaining joints of the foot.

Patellectomy with vastus medialis obliquus advancement for comminuted patellar fractures: a prospective randomised trial.

We have compared the results of simple patellectomy (group A, n = 16) and patellectomy with advancement of the vastus medialis obliquus (group B, n = 12) in a prospective, randomised trial, with a minimum follow-up of three years. The results in group B were significantly better (p < 0.001) than those in group A. Although the patella should be preserved if possible, we advocate advancement of the vastus medialis obliquus when patellectomy is necessary.

Compartment syndrome after intraosseous infusion: an experimental study in dogs.

An experimental study was designed to investigate the development of compartment syndrome with the use of an intraosseous line in dogs. We used an open technique for insertion of a 20-gauge spinal needle to the tibia. The needle was secured to the tibia with bone cement. Throughout the intraosseous infusion of saline with radio-opaque dye (rate, 480 mL/h), serial radiographic examination and pressure monitoring of the anterolateral compartment of the leg was performed. Although there was no change up to approximately 350 mL of fluid infusion, the radio-opaque dye was detected in the soft tissues and compartment pressure increased to more than 35 mm Hg. Compartment pressure continued to increase in direct proportion to the amount of dye infused. In the present study, the possible technical errors, which may cause compartment syndrome, have been eliminated. However, compartment syndrome developed because of the failure of microvasculature within a muscle adjacent to bone. We suggest that there is a need for a dose-and time-dependent scale for safe intraosseous infusion.

Setscrew distal locking for intramedullary nails: a biomechanical study.

OBJECTIVE: This biomechanical study was undertaken to examine the effectiveness of setscrew distal locking in a static intramedullary (IM) femoral nail on the stability of fixation of femoral shaft fractures. DESIGN: Fifteen fresh-frozen cadeveric femora were randomly separated into three groups of five bones and transversely sectioned immediately distal to the isthmus. After the insertion of the large-diameter nails, distal locking was obtained by conventional method in the first group. In the second group, set-screw design was used in which two transverse screws penetrated only the lateral cortex of the femur and compressed the nail in the intramedullary canal. No distal locking was used in the third group. INTERVENTION: All instrumented femurs were mounted on a servohydraulic testing machine and tested in both rotations (20 degrees) and axial compression (amplitude: 1,000 Newton). MAIN OUTCOME MEASUREMENT: Loading-versus-displacement data, acquired at a ten-Hertz sampling rate, were calibrated and used to calculate maximum torque, stiffness, and energy capacity to failure. Maximum displacement and axial stiffness also were determined. RESULTS: Mean maximum torque at 10 degrees for each group were 15.3+/-4.8 newton-meters for the interlocking group, 8.5 +/-1.2 newton-meters for the setscrew group, and 3.6+/-2.7 newton-meters for the nonlocked femora. At 20 degrees of rotational displacement, the torque measured 37.4+/-2.6 newton-meters; 15.0+/-4.0 newton-meters; and 5.3+/-3.1 newton-meters, respectively (p < 0.05). Mean torsional stiffness was 1.17+/-0.76 newton-meters per degree for the setscrew group and 1.34+/-0.83 newton-meters per degree for the interlocking group (p > 0.05). The setscrew design provided 87 percent of the torsional rigidity of the interlocking group. In the axial compression test, mean maximum shortening was 1.1+/-0.3 millimeters in the interlocking group and 1.4+/-0.6 millimeters in the setscrew group (p > 0.05). The mean stiffness on longitudinal compression provided by the interlocking screws and the setscrews was 918 and 860 newton-meters per millimeter, respectively. CONCLUSION: The distal setscrew design provides adequate distal fixation of intramedullary nail for patients in the postoperative rehabilitation period of the femoral shaft fractures treated with intramedullary nailing.

The relationship between the tibialis posterior tendon and the accessory navicular.

Out of a total of 116 cadaver feet, 29 specimens were selected by means of palpation of the tuberosity of navicular for a possible presence of the accessory navicular. They were then radiographed and the accessory navicular was detected in ten. Also three fresh amputation specimens with an accessory navicular were added to the study. A total of 13 legs was dissected and in nine of them, the tibialis posterior tendon inserted directly into the accessory navicular without extending to the sole of the foot. In these feet, the second part of the tibialis posterior tendon originated from the accessory navicular, extending to the normal insertions. There was no connection between these two parts and when traction was applied to either one, no movement was observed in the other. Also a fibrocartilaginous mass was detected in four specimens, probably formed to resist the friction between the tendon and the bone. These results may explain the pronated foot in the presence of the navicular, due to the loss of the function of the tibialis posterior tendon.

Normal ranges of ulnar and radial deviation with reference to ulnar variance.

We aimed to determine the normal ranges of radial and ulnar deviation of the wrist in relation to the ulnar variance. A total of 102 healthy subjects (204 wrists) were included in the study. The ranges of radial and ulnar deviation of the wrists were measured using a universal goniometer. Ulnar variance was assessed manually or radiographically, and recorded as ulna minus, ulna plus or ulna minus/plus. When the ranges of radial and ulnar deviation were compared with ulnar variance, ulnar deviation was greater in ulna minus subjects and radial deviation was greater in ulna minus/plus subjects. There was no significant difference in the total range of radio-ulnar deviation. The results of this study indicate that ulnar deviation is greater in ulna minus wrists, and we suggest that ulnar variance should be recorded alongside measurements of radial and ulnar deviation.

Trapezio-lunate external fixation for scaphoid fractures. An experimental and clinical study.

Trapezio-lunate external fixation for scaphoid fractures has been investigated experimentally and clinically. Six below-elbow fresh amputation specimens in which proximal, waist and distal scaphoid fractures were created, displaced, reduced and externally fixed were used for an experimental study and after 10,000 extension-flexion movements of the wrist, no displacement was observed. A strain-gauge study confirmed the strains at the fracture site. Seven patients were treated in this way. No immobilization was necessary and all patients returned to their regular employment within 3 days and all fractures were united without displacement. The technique overcomes certain disadvantages of plaster fixation and internal fixation of scaphoid fractures.

The morphological and morphometric features of the scaphoid.

This cadaveric study used 200 scaphoid bones (100 left and 100 right) to assess 24 morphological and 11 morphometric parameters. At least one morphometric feature was absent in all scaphoids, though the tubercle and the dorsal sulcus were present in all instances. There were significant differences in the circumferences of the waist and the base of the tubercle, the width of the main sulcus and the secondary height of the tubercle between left and right scaphoids. Detailed knowledge of anatomy and correlations between the anatomical features may help better understanding of clinical problems.

Various manifestations of hyperphalangism.

Hyperphalangism is a rare congenital anomaly, with an extra phalanx between the phalanges in a finger. About 100 cases have been recorded in the literature. We report 42 cases in six generations of a family with various manifestations.

Avascular necrosis of the scaphoid treated by total excision and radial advancement osteotomy.

Total scaphoid excision and radial advancement osteotomy has been investigated in a cadaveric and clinical study. In three below-elbow fresh amputation specimens, the technique was utilized and stability was checked by radiographs. Instability on ulnar deviation was prevented by extensor carpi radialis longus tenodesis. Four patients were treated in this way. The wrist was immobilized in a below-elbow splint for 45 days, then active motion was encouraged. After 10 months, three patients had excellent results and one patient had good result using the criteria of Cooney et al (1987).

Medium-term results of trapezio-lunate external fixation for scaphoid fractures.

We treated 36 scaphoid fractures in 34 patients with trapezio-lunate external fixation. According to the Herbert and Fisher classification, there were 16 type B1, 14 type B2, four type B3 and two type B4 fractures. Trapezial and lunate pins broke in three patients and these were rated as failures. The remaining 33 fractures were followed-up for 3 years and all had excellent outcomes, without signs of arthritis, avascularity or instability.

Calcitonin inhibits heterotopic bone formation in rats.

The effect of salmon calcitonin on heterotopic bone formation in rats was analysed. Thirty days after implantation of demineralized bone matrix, the weights of implants from animals receiving calcitonin were reduced, in contrast to the increase shown in the untreated control group. In the control group, the implants were visible on roentgenograms at the 20th day and histologic examination revealed new bone formation, whereas in the calcitonin-treated group the implants were never visible on roentgenograms throughout the study and only remnants of implants could be detected histologically. This study suggests that calcitonin inhibits heterotopic bone formation in rats.

Treatment of severe residual clubfoot deformity by trans-midtarsal osteotomy.

This study reviews the preliminary results of transmidtarsal osteotomy performed on 11 patients (12 feet) who previously underwent surgery for resistant clubfoot and needed further surgery for severe residual deformities. Opening wedge medial cuneiform osteotomy, closing wedge cuboid osteotomy, and truncated wedge middle and lateral cuneiform osteotomy were performed. The procedure was performed initially on normal cadaver feet. The average improvement of anteroposterior talo-first metatarsal angle was 20 degrees and lateral calcaneo-first metatarsal angle was 16 degrees. The authors conclude that with this simple procedure, angular and rotational correction in three planes can be obtained simultaneously in severe residual clubfoot deformity without the need for extensive soft tissue release.

Postoperative immobilisation orthosis for surgically corrected hallux valgus.

A postoperative immobilisation orthosis was developed at the School of Physical Therapy and Rehabilitation, Department of Orthotics and Prosthetics, and applied from the first postoperative day as an alternative device for ambulation of patients who have undergone hallux valgus surgery while maintaining the corrected position. The orthosis is constructed with polyethylene thermoplastic sheet of 3mm thickness and Velcro. During the ambulation period, there was no complication or complaint due to its application and the position of the great toe was maintained. The time of the orthotic application was six weeks. The orthosis has allowed patients to walk with full weight bearing from the postoperative first day without any complication or recurrence.

[In vitro evaluation of antibiotic diffusion from antibiotic impregnated xenografts]. / Evaluation in vitro de la diffusion des antibiotiques à partir d'une xénogreffe imprégnée d'antibiotiques.

PURPOSE OF THE STUDY: The purpose of the study was to evaluate xenografts as a slow release antibiotic delivery system, as xenografts also have excellent biocompatibility and osteogenesis-stimulating effect. MATERIAL: Xenograft (Unilab Surgibone) blocks of 5 x 5 x 5 mm were used in the study. Antibiotics used for impregnation were gentamicin sulphate, ciprofloxacin and penicillin G. METHODS: In the pilot study, xenograft blocks impregnated with gentamicin sulphate solution and the contact time was between 1/2 to 10 hours. Then the grafts were incubated and the antibiotic concentration was measured in the elution fluid changed every day. The minimum contact time to release the antibiotic 10 days over 0.5 microgram/ml was 8 hours. The 8 hours contact time was used in the main study to evaluate gentamicin sulphate, ciprofloxacin and penicillin G. The method was the same as in the pilot study. RESULTS: All antibiotics showed similar release patterns reaching their peaks on the 5th day and then gradually decreasing below the effective level (0.5 microgram/ml) approximately on day 10. DISCUSSION: Although various materials have been used to deliver antibiotics, they have some certain disadvantages especially reduced biocompatibility. The superiority of xenografts over other materials, is not only biocompatibility but also to facilitate osteogenesis. The only objection may be the relatively short duration of release (10 days) but the length of antibiotherapy is controversial and standard 6 weeks of administration has no documented superiority over other time intervals. CONCLUSION: Our delivery system is superior to others as its function is not only to deliver antibiotics but has its place in orthopedic practice to fill defects and stimulate osteogenesis. Also the preparation of this system is not time and skill consuming.