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At least 1,621 records · Page 90Linked to original sources
PubMed1999

Effect of quadriceps exercise on synostosis following tibial osteotomy with internal fixation: a finite element simulation.

OBJECTIVE: To clarify the influence of quadriceps muscle exercises on the apposed bony surfaces of the tibia after a high tibial osteotomy. The study was designed so that the instability at the osteotomy could be evaluated by a finite element simulation. BACKGROUND: A detailed knowledge of the effects of quadriceps exercises on the healing tibia may lead to a solid rationale for exercise prescription. METHODS: Using a three-dimensional finite-element method, we calculated displacement at the site of surgical repair of a tibia with an osteotomy and fixation plate attached. Construction of the finite element model of the tibia and subsequent calculations were done with the aid of commercial software. Boundary and loading conditions were calculated for two situations: a straight leg raising exercise and a full knee extension beginning from 90 degrees of knee flexion. RESULTS: In the straight leg raising exercise, the surgically cut surfaces were apposed tightly, whether or not an external load was added. For the knee extension exercise, on the other hand, separation occurred when the lower leg began at a full vertical orientation of 90 degrees of knee flexion, but as the lower leg diverged from the vertical orientation, compression began to come into play and progressively increased. CONCLUSIONS: A position of 90 degrees of knee flexion with the lower leg vertical should be considered hazardous to the integrity of the surgically cut and apposed surfaces. RELEVANCE: Currently, the basis for deciding the timing and intensity of exercise is simply clinical experience. A more detailed knowledge of the effects of quadriceps exercise on the healing tibia may lead to a more solid rationale for exercise prescription in the postoperative care of a high tibial osteotomy.

Biomechanical Phenomena↗
PubMed1998

Temporary internal fixation of the scaphotrapezio-trapezoidal joint for the treatment of Kienböck's disease: a preliminary study.

Temporary scaphotrapezio-trapezoidal (STT) fixation with Kirschner wires (K-wires) has been used in the treatment of 16 cases of Kienböck's disease since 1988. Twelve of these cases with a follow-up of at least 1 year were reviewed. Eight patients were women and 4 were men and the average age at the time of surgery was 44 years (range, 20-67 years). Five cases were treated with temporary STT fixation and vascular bundle implantation (group V), and 7 cases were treated with temporary STT fixation and tendon roll implantation (group T). K-wires were removed between 16 and 26 weeks after surgery (average, 18.6 weeks) in group V, and between 8 and 13 weeks (average, 9.7 weeks) in group T. The follow-up periods ranged from 12 to 92 months (average, 38 months). Postoperative wrist pain disappeared in 7 cases and decreased in 5. The postoperative arc of wrist flexion and extension increased from 97 degrees to 108 degrees in group V and from 85 degrees to 103 degrees in group T. Grip strength improved from 22.2 to 30.6 kg in group V and from 11.4 kg to 17.7 kg in group T. X-ray evaluation revealed that the mean carpal height ratio was 0.488 before surgery, 0.489 during STT fixation, and 0.480 at the final follow-up. The carpal height decreased in 3 cases (2 in group V and 1 in group T). The postoperative radioscaphoid angle improved in all cases during K-wire insertion and regressed after removal of the K-wire, eventually showing a decrease in 4 cases, an increase in 3 cases, and no change in 5 cases.

Adult↗
PubMed1986

Biomechanical analysis of internal fixation techniques for proximal interphalangeal joint arthrodesis.

Although numerous fixation techniques have been developed for performing small joint arthrodesis, no previous study of the biomechanical properties of these constructs has been published. The strength of specimens of arthrodesis of the proximal interphalangeal joint performed with cadaver material was determined for three-point anteroposterior bending, axial torsion, and lateral cantilever bending stress. Crossed Kirschner wires, intraosseous wiring, and figure of eight tension-band wiring were studied. Figure of eight tension-band wiring demonstrates superior strength in anteroposterior bending and torsion. For lateral bending stress, no significant difference exists among the techniques studied.

Arthrodesis↗
PubMed1997

Internal fixation strength of suture anchors--update 1997.

Two new areas of anchor development are biodegradable anchors and "mini" anchors. The group of biodegradable anchors tested include the Bio-Anchor, LactoSorb, Biofix, Bio-Statak, Mini Screw suture anchor, DePuy 4.5 molded, DePuy 4.5 machined, DePuy 3.5 machined, TAG Wedge 4, TAG Rod 2, TAG Wedge 3, TAG Wedge 2, and Stealth. "Mini anchors" have drill holes or minor diameters of < 2.2 mm. Those tested include the Mini Revo and Bio-Anchor, miniHarpoon, mini Mitek and Fast in 3, Statak 1.5 and 2.5, SB 2 and PeBA 3, Corkscrew 5, Corkscrew 3.5, and Fastak A2, Ogden 2.5, TAG Wedge 2, ROC 1.9, and Questus 2.5. Additional anchors tested that fit neither category include the Anspach, Questus 3.5 and 5.0, SB 3 and PeBA-C, Ogden 3.5, Fast in 4, Ultrafix, and the ROC 3.5, ROC 2.8, ROC 2.3, and ROC XS. An anchor comparison, using an established protocol in fresh porcine femurs, recorded failure strength, failure mode, eyelet size, minor and major diameters, and drill hole sizes. Except for the Bio-Anchor and TAG Wedge 2, biodegradable anchors tend to be larger to compensate for their lower strength relative to metal. Biodegradable screw anchors' predominant failure mode was eyelet cutout, whereas biodegradable nonscrew anchors failed to predominantly by anchor pullout. From an initial mechanical perspective, these biodegradable anchors perform acceptably. Both biodegradable and "mini" anchors include screw and nonscrew designs. As expected, screw designs perform well and generally fail at higher loads than nonscrew anchors. Although biodegradable anchors, as a group, are not as strong as metal anchors, they are stronger than the sutures for which they are designed. The move to smaller ("mini") and biodegradable anchors is supported by these data. Whether an anchor fails at twice the suture breaking strength or 10 times the suture breaking strength should make no difference.

Animals↗
PubMed1988

Fractures and non unions of the proximal pole of the carpal scaphoid bone. Internal fixation by a proximal to distal screw.

We report a new proximal to distal screw fixation technique for proximal pole fractures and non unions of the carpal scaphoid (type I of the Schernberg, Elzein and Gerard classification). Seven cases of non union with a live proximal polar fragment were operated from 1984 to 1986 with 4 excellent and 2 fair results and one failure. Three recent displaced fractures were also treated this way, with 3 excellent results. This useful technique is worth knowing and deserves a place in the treatment of scaphoid fractures, especially type I proximal pole fractures which represent a challenging problem, and are in no way comparable to other locations.

Bone Screws↗
PubMed1999

Condylar positional changes after mandibular advancement surgery with rigid internal fixation.

The purpose of this retrospective investigation was to describe condylar positional changes in patients after mandibular advancement surgery. By superimposing on clearly identifiable cephalometric landmarks (ie, mandibular symphysis and rigid fixation screws), condylar positional changes from immediately after surgery to orthodontic appliance removal were extrapolated. Although the mandibular symphysis generally moved in either an anterior or posterior direction after surgery, condylar movements were exclusively in an upward vertical direction. Correlations were found between several measured variables, including a tendency for increased superior postsurgical movement of the condyles with increasing magnitudes of surgical advancement of the mandible. This long-term instability of skeletal relationships may be caused by a wide variety of interacting factors and events.

Adolescent↗
PubMed1997

Internal fixation of hip osteotomy in children. Successful healing in 26 children without postoperative casting.

We assessed the necessity of postoperative casting when a plate was used for fixation of a proximal femoral varus osteotomy. 26 children without postoperative immobilization were compared to 17 children with a cast. No complications were encountered in either group of children and all osteotomies showed similar healing. Our findings indicate that plate fixation provides adequate stability for healing of the osteotomy.

Bone Diseases, Developmental↗
PubMed1989

Internal fixation of the unstable cervical spine using posterior Roy-Camille plates: preliminary report.

We reviewed 13 cases of unstable cervical spine treated by stabilization with posterior Roy-Camille plates and fusion. The patients were treated between 1985-1988. Six patients had acute traumatic episodes, three patients had posttraumatic instabilities, one patient had laminectomy for cervical spondylotic myelopathy, and three patients had metastatic bone disease. All had successful fusion in approximately 3 months without complications. The indications and techniques of posterior Roy-Camille plating are outlined.

Adult↗
PubMed1991

Immediate internal fixation of high-energy open forearm fractures.

Eighteen patients with Gustilo and Anderson Grade III A (7), III B (8) or III C (3) open diaphyseal forearm fractures were treated with a protocol consisting of extensive primary debridement, immediate open reduction, dynamic compression plate fixation, and vascular repair when indicated. This was followed by routine redebridement at 24 to 48-h intervals until wound status allowed completion of soft tissue reconstruction. Bone grafting was performed at 8 to 10 weeks following obtainment of a closed soft tissue envelope for injuries with extensive comminution or bone loss (5 patients, 7 fractures). Subsequent procedures such as tendon transfers, scar revision, joint arthrodesis, or secondary nerve reconstruction were required in 8 of 18 patients. Minor complications related to delayed wound healing occurred in 3 individuals (15%). One deep infection of a fractured radius occurred in a patient with a floating elbow and failed free flap. Salvage with debridement, retention of hardware, and a second free flap resulted in fracture union. One patient required a second bone graft to obtain union of a segmental forearm defect. Amputation was performed in one patient following failed forearm replantation with greater than 8 h warm ischemia time. Immediate debridement and plate fixation of Grade III forearm fractures performed in conjunction with aggressive soft tissue management provided good or excellent results in 12 patients (66%) and is an acceptable treatment alternative in these difficult injuries.

Adolescent↗
PubMed1991

Internal fixation with a self-compressing plate and lag screw: improvements of the plate hole and screw design. 1. Mechanical investigation.

For a number of years, self-compressing plates, with oval holes and using special drill guides, have been in use. Recently, the advantages offered by lag screw interfragmentary compression inserted through the plate have gained prominence. Often such screws are inserted in an inclined position toward the fracture plane for better efficiency. It has also become evident that inclined screws placed into oval holes undergo a displacement toward the fracture. Efforts to improve the effect of this technique have led to a new plate and screw interaction that is described herein. The result is versatility and efficiency of the fracture fixation.

Biomechanical Phenomena↗
PubMed1991

Internal fixation with a self-compressing plate and lag screw: improvements of the plate hole and screw design. 2. In vivo investigations.

A mechanically improved design of bone plate and screw was compared in vivo with conventional plate fixation. This method was investigated biologically in a standardized osteotomy model on sheep tibiae. It was found that maintenance of reduction of an osteotomy was facilitated and there was no adverse effect of this fracture fixation system on bone remodeling. The modified implant permits the reduced surgical approach to the bone through one plane and optimal fixation of the fracture or osteotomy.

Animals↗
PubMed2002

Open reduction and internal fixation of unstable distal radius fractures: results using the trimed fixation system.

OBJECTIVE: The purpose of this study was to evaluate the early results of patients with displaced and unstable distal radius fractures treated with fragment-specific fixation. DESIGN Prospective and consecutive. SETTING: Private orthopaedic practice. PATIENTS/PARTICIPANTS: Twenty-five patients with 27 fractures with an average follow-up of 29 months (range 24-36 months) treated with fragment-specific fixation for unstable radius fractures. MAIN OUTCOME MEASUREMENTS: Clinical and radiographic examination. Disabilities of the arm, hand, and shoulder and patient-rated wrist evaluation outcome measures. RESULTS Patients had an average 61 degrees of dorsiflexion and 54 degrees of palmarflexion at the wrist. Twenty-five fractures healed in acceptable alignment, with one loss of reduction and one patient death. Mean +/- standard deviation DASH score was 17 +/- 18, and PRWE score was 19 +/- 22. CONCLUSION: Unstable distal radius fractures can be reliably and anatomically reduced and stabilized using fragment-specific fixation. Fixation of markedly comminuted fractures is secure enough to allow immediate motion and does not require casting or external fixation. Preliminary clinical and radiographic results are excellent, and patient satisfaction is high. Anatomic reduction with early motion can be achieved in a routine fashion on unstable distal radius fractures using the described technique.

Adult↗