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At least 109 records · Page 6Linked to original sources

New problems in old bones: closed nailing of the shaft of the femur.

Closed medullary nailing is now established as a routine treatment of fractures of the shaft of the femur. However, the quality of the bone in elderly patients is such that serious technical difficulties may arise during the operation. Three typical cases illustrate the problems that may occur and point the lesson that closed nailing in the elderly ought not to be undertaken by the inexperienced surgeon.

Aged↗

Internal fixation of nonunions.

We review the two major types of internal fixation of nonunions (plating and intramedullary nailing), and analyze nonunions in different locations (upper and lower extremities). Depending on the type and the location of the nonunion, plating or intramedullary nailing may be selected. Both have advantages and disadvantages: plating requires opening the nonunion site, which entails some damage to the soft tissues, and carries with it a risk of secondary infection. With plating, it often is impossible to do a real decortication because the periosteum may be thin and poorly adherent to bone, and the quality of bone may prove insufficient to achieve good fixation with most of the screws. However, plating still is used in metaphyseal nonunions, and angular deformities may be corrected by applying a plate under tension on the convex side of the bone. Nailing can be done percutaneously in numerous cases; it has a smaller risk of infection but, should an infection be present, there is a risk that it may spread over the entire length of the medullary cavity. Nailing stimulates bone formation, but noninterlocking nails may cause shortening and rotational instability of the nonunion site. Plate fixation was popular approximately 20 years ago, but now has been largely superseded by intramedullary nailing except for proximal or distal nonunions. Dynamic locking nails are preferable. Successful treatment of nonunions often requires several consecutive surgical actions and a global strategy must be established from the beginning, taking care not to interfere with the successive steps.

Arm Injuries↗

Mechanical evaluation of humeral interlocking intramedullary nails.

Implantation of an interlocking intramedullary nail has rapidly become the modality of choice for the management of various fractures of the humeral shaft; namely, those that are not minimally displaced, impacted and/or stable. The mechanical properties of the nail per se or the nail-bone construct are essential to the nail's satisfactory clinical performance. The present work is a critical review of this topic, using reports given in the opne literature. Whence, gaps and unresolved controversies in the current knowledge base are identified. Expositions on future work, based on the foregoing observations as well as uncharted topics, are presented.

Adult↗

Impending and actual pathological fractures in patients with bone metastases of the long bones. A retrospective study of 233 surgically treated fractures.

OBJECTIVE: Analysis of short-term and long-term complications after cemented osteosynthesis for pathological fractures. DESIGN: Retrospective study. SETTING: South Municipal Hospital and the Daniël den Hoed Cancer Centre, Rotterdam, The Netherlands. SUBJECTS: 199 patients consecutive surgically treated between 1978 to 1990 for 233 fractures (161 actual and 72 impending) caused by metastatic lesions of the femur, humerus and tibia. INTERVENTIONS: Local resection of the tumour was followed by endoprostheses (n = 52) and by internal plate osteosynthesis (n = 167); 14 fractures were treated with intramedullary nails. Bone cement was added in 211 cases (91%). MAIN OUTCOME MEASURES: Pain relief, mobilisation, complications. RESULTS: Pain relief was achieved in about 90%. 145 (76%) who were treated for fractures of the lower extremity were able to walk again. There were 13 local complications: 26 (11%) implanted devices failed (cumulative probability 40%, after 60 months). In 11 cases the fixation failed after 7 weeks. The failure rate was 16% in the subtrochanteric region treated with an angled blade (probability 70% after four years). The patients' survival rate was 55% after six months and 20% at two years. CONCLUSION: Despite the poor life expectancy, our results indicate that hemiarthroplasty or osteosynthesis with bone cement for treatment of pathological (impending) fractures is a safe way to restore limb function and to improve quality of life.

Adult↗

Bending and torsional stiffness in cadaver humeri fixed with a self-locking expandable or interlocking nail system: a mechanical study.

OBJECTIVES: This study was designed to gain data about a new expandable, noninterlocked intramedullary nail's capacity to stabilize unstable transverse humeral shaft fractures without the need for interlocking, thus making nail implantation simpler and to prove our goal hypothesis: that in a midshaft osteotomy of the humeral shaft the expandable humeral nail will show the same bending and torsional stiffness as an interlocked humeral nail, when implanted correctly according to the manufacturer's instructions. DESIGN: Pair randomization. SETTING: Mechanical laboratory testing. PARTICIPANTS: Eight pairs of freshly harvested cadaveric humeri. INTERVENTIONS: Fracture model was a midshaft transverse osteotomy, gapped to 3 mm. Each humerus pair received an expandable humeral nail (Fixion) or an interlocked humerus nail (Synthes) through a retrograde approach. The humeri were fixed in polymethylmethacrylate cylinders and tested in a servo-pneumatic material-testing machine. MAIN OUTCOME MEASUREMENTS: Torsional stiffness and bending stiffness of the nail-bone-construction. RESULTS: Expandable nails (interlocked nails) showed a lateral bending stiffness of 0.73 +/- 0.14 (0.63 +/- 0.1) KN/mm (P = 0.026) and a frontal bending stiffness of 0.67 +/- 0.18 (0.58 +/- 0.09) KN/mm (P = 0.084). Torsional stiffness values were 0.13 +/- 0.19 (0.43 +/- 0.09 Nm/degrees) (P = 0.012). Lower torsional stiffness in the expandable nail group was observed in humeri with a funnel shaped proximal intramedullary canal. CONCLUSIONS: The nail systems showed similar characteristics for frontal bending (P = 0.084), but not for lateral bending (P = 0.026). For lateral bending, the Fixion nail showed significantly more stiffness than the UHN nail (P = 0.026). There was significantly lower torsional stiffness with expandable nails compared with interlocked nails. Clinical correlation would suggest that in rotationally unstable fractures (A2 and A3 diaphyseal fractures), interlocked nails would provide increased stability over expandable nails.

Biomechanical Phenomena↗

Biomechanics of intramedullary fracture fixation.

Intramedullary rodding allows excellent control of bending forces on long bone fractures when adequate sized rods are used. This is made possible by reaming when necessary. Torsional stability is poor if adequate bone nail contact is not obtained and there is little bone fragment interdigitation. This can be optimized with the interlocking system, especially with proximal and distal fractures. Intramedullary rods allow transmission of compressive load so there must be adequate bone to bone contact without comminution to prevent shortening. If a great deal of comminution is present, an interlocking system must be used to resist compressive loads. The interlocked devices have not been proven to be a detriment to union and indeed are a semi-rigid fixation system when used in comminuted shaft fractures. The strength of an osteosynthesis with an intramedullary rod depends on the geometry of the rod and the geometry of the fracture complex. Both locked and nonlocked intramedullary rods perform extremely well when one understands the mechanical principles involved in intramedullary rodding and pays close attention to detail.

Biomechanical Phenomena↗

Biomechanical and clinical effects of adding interfragmentary wiring to locked nailing for humeral nonunions.

BACKGROUND AND PURPOSE: The use of locked nailing for the treatment of humeral nonunions is threatened by the potential of initial instability which may result in residual fracture gap and motion and is detrimental to fracture healing. This study investigated the biomechanical and clinical effects of adding interfragmentary wiring to reduce the initial instability in the treatment of humeral nonunion. METHODS: The biomechanical study compared the mechanical properties of 3 fixation methods: locked nail alone, with staple, and with interfragmentary wiring. Composite humeri were transected to simulate nonunion and were retrograde nailed. Nail-bone constructs were examined by non-destructive bending tests and destructive torsional tests. The initial instability, fixation stiffness and strength were measured and compared. The clinical study compared 21 nonunions treated by locked nailing alone and 30 nonunions treated by locked nailing with interfragmentary wiring. The indication for wiring was persistent nonunion gap or motion during operation. The union rate, time to union, functional recovery of the adjacent joints and the time for functional recovery were compared between the treatment groups. RESULTS: Biomechanically, in both bending and torsional tests, locked nailing with a staple or wiring resulted in significantly less initial instability than locked nailing alone. Test results for bending stiffness, torsional stiffness, or torsional strength did not differ significantly among the 3 fixation methods. In the clinical study, interfragmentary wiring had the advantage of providing tight nonunion compression, which was beneficial for nonunion healing and promoted early postoperative exercise. Patients treated with locked nailing with interfragmentary wiring had significantly shorter time to union and faster shoulder functional recovery (p < 0.05). CONCLUSIONS: Adding interfragmentary wiring was an effective and safe procedure in humeral nonunions treated with locked nailing.

Biomechanical Phenomena↗