Limb salvage surgery with vascular reconstruction.

Vascular reconstruction and limb salvage surgery has been the authors' preferred approach when malignancy involves major vessels of the extremities. Treatment of 16 patients involved resection, with vascular grafting in 14 patients and rotationplasty in two patients. The major vessels were surrounded by tumor in six patients, nearly encased in three patients, invaded by tumor in four patients, and widely contaminated by intralesional surgery in three patients. The tumor stage included one Stage IB, 12 Stage IIB, two Stage IIIB sarcomas, and one multiply recurrent carcinoma. The largest average tumor dimension was 9.5 cm, and the length of grafting was 14 cm. Major nerves were sacrificed in eight (50%) patients, flaps or muscle transfers were done in seven (44%), chemotherapy was administered in nine (56%), radiation therapy was used in four (25%), and pulmonary metastasectomy was done in two (12%). At a mean followup of 56 months, 50% (eight of 16) of patients were alive without disease. Local recurrence was 12% (two of 16 patients), and infection was 12% (two of 16 patients). Limb salvage was achieved in 88% (14 of 16 patients), and functional status was judged good or excellent in 81% (13 of 16 patients). The complication rate observed in this subset of patients is significant, yet local control and the incidence of major complications was acceptable. Results observed from this series and data gathered from the literature clearly indicate that patients can avoid amputation, despite malignant involvement of major vessels to their extremities.

Retrograde femoral nailing: a focus on the knee.

A consecutive series of 23 patients with reamed retrograde femoral nails was reviewed. Nails were placed through the intercondylar notch with a minimal incision. Nineteen patients with retrograde femoral nails were available at an average follow-up of 19.3 months. The union rate was 100% with no infections or malunions. No second surgeries were required for union. Knee range of motion averaged 109 degrees and was greater in those patients with shaft fractures (117 degrees) than in those with supracondylar-intercondylar fractures (91.3 degrees) (P=.02). Pain (0-3 scale) averaged 0.36. Hospital for Special Surgery knee scores averaged 80.4 (90% good or excellent results). Minor knee pain (55%) and secondary surgeries (35%) were common. The only fair or poor results were in patients with preexisting osteoarthritis. A literature review of 14 papers and abstracts was conducted. Exposure, often extensive initially, is more recently percutaneous. The infection rate is acceptable (0-14%), with knee sepsis uncommon. Lower union rates were observed for supracondylar femur fractures (80%-84%) than for femoral shaft fractures (85%-100%) after a single surgery. Second surgeries are common (14%-60%). Varus/valgus malunion, common (12%-29%) with the initial extrarticular entry site, occurs less with the intercondylar entry site. The antegrade femoral nail allows for better control of proximal shaft fractures, while the retrograde femoral nail is more reliable in controlling distal shaft fractures. Rotational malunion still remains a problem. Mild knee pain is common (13%-60%). The treatment of supracondylar femur nonunions with retrograde femoral nailing is disappointing.

Cervical facet dislocation: management following delayed diagnosis.

This study examined the influence of early versus late initial presentation of patients with cervical spine facet dislocation on presentation, neurologic deficit, and the success of closed reduction. Thirty-four patients were studied, and approximately 35% presented at least 72 hours following their injury. Compared with patients who presented early, this late group demonstrated less neurologic deficit, and closed reduction was less likely to be successful. These findings suggest that a distinction should exist in the management algorithm between early versus late presentation of cervical facet dislocation.

The holding strength of cannulated screws compared with solid core screws in cortical and cancellous bone.

The comparative holding strength of cannulated screws (CS) versus solid core screws (SCS) has not been reported, although differences exist in the respective diameters of their outer thread and pilot drill holes. Our objectives were to characterize these differences and determine the holding power of CS compared with SCS in cortical and cancellous bone. The dimensions of the Synthes (Paoli, PA) 3.5-mm SCS, 3.5-mm CS, 6.5-mm SCS, and 7.0-mm CS were measured, and the cross-sectional area for thread purchase was calculated. Using adult canine femurs, small-fragment 3.5-mm SCS were inserted in cortical (midshaft) and cancellous (condyle) bone of one limb, and CS were placed in similar locations in the contralateral limb. The same technique was used for large-fragment CS and SCS. Pull-out testing was performed using an MTS machine (MTS Systems, Minneapolis, MN) with axial loads applied at 5 mm/s, and data were analyzed to determine the effects of screw type, location, and size. Differences in CS versus SCS design result in higher cross-sectional areas available for SCS thread purchase. Yet no significant differences exists between screw types (SCS vs. CS) in either cortical or cancellous bone. In cancellous bone, large-fragment screws required more force to pull out than did small screws (p = 0.000). The mean force required to pull out small-fragment screws was higher in cortical bone than in cancellous bone (p = 0.000). These data suggest that the clinical decision to use CS versus SCS should not be based on pull-out strength.

Biomechanics of healed experimental fractures.

Biomechanical properties of osteotomies and physiologically fractured canine femurs fixed with six-hole stainless steel AO/DCP plates (Synthes: Paoli, PA) were investigated with torsional loading 12 weeks postoperatively and were compared. Biomechanical evaluation of fracture healing with compression plate fixation requires a well controlled fracture creation technique which should reflect closely the natural process. Osteotomy has been suspected of creating ;local bone necrosis, a segmental defect, and subsequent healing patterns which do not mimic those following a more physiologic fracture. Two fracture techniques were compared in the mid-diaphyseal canine femur. An osteotomy was created in one limb and stabilized with a dynamic compression plate, while the contralateral limb was fractured physiologically utilizing four-point bending (modified technique of Ashhurst et al.) and also stabilized with a dynamic compression plate. Comminution developed in one animal during the four-point bending fracture creation technique and nonunion developed in an animal following osteotomy. Following sacrifice at three months, dynamic torsion testing demonstrated no statistical difference in mean torque to failure (osteotomy = 27.7, SD 9.4 N m; physiologic fracture = 28.4, SD 5.0 N m). Stiffness, rotation to failure, and energy to failure were also analysed and demonstrated no statistical difference.

Dynamic compression plate fixation: a biomechanical comparison of unicortical vs bicortical distal screw fixation.

The use of unicortical screws instead of bicortical screws in the extreme outer holes of dynamic compression plates (DCPs) has been recommended to minimize the stress riser effect at the end of the plates. The authors examined in vitro two groups of paired canine femurs after compression plates had been applied to the anterolateral diaphyseal surface bilaterally. Group I: intact paired femurs with bicortical peripheral screws in one DCP and unicortical peripheral screws in the other; Group II: osteotomized paired femurs again comparing unicortical and bicortical peripheral DCP screws. All specimens were torsion tested to failure and the torque, stiffness, energy, rotation, and failure fracture length were calculated. Unicortical screws did not enhance the torsional strength in either group, and significantly compromised stiffness, energy, and rotation in the osteotomized group. The only apparent benefit of unicortical peripheral screws in a DCP was a shorter, less comminuted fracture upon failure.

Strength reduction and the effects of treatment of long bones with diaphyseal defects involving 50% of the cortex.

Currently, three criteria are accepted as indications for prophylactic internal fixation of metastatic disease in long bone, including lesions (a) destroying 50% or more of the cortex; (b) 2.5 cm or greater in diameter; or (c) with pain unrelieved by radiation therapy. Using an oblong defect configuration in which one half of the cross-sectional area was destroyed, canine femora were torsion-tested at high speed to determine (a) the actual strength reduction incurred by a lesion destroying 50% of the cortical circumference, and (b) the effects and benefits of internal fixation using polymethylmethacrylate and/or a six-hole compression plate on such a defect. The femurs with a 50% circumferential cortical defect demonstrated only 12.7 +/- 3.8% of intact strength. Defects treated with a combination of plating (all screws bicortical) and polymethylmethacrylate (torque to failure 4.39 +/- 0.90 times greater than the defect alone or TE/TD = 4.39 +/- 0.90) were statistically stronger than defects treated with polymethylmethacrylate alone (TE/TD = 2.48 +/- 0.66; p less than 0.025) or by plating alone (TE/TD = 2.61 +/- 0.91; p less than 0.025), but torque-to-failure was only increased to approximately 56% of an intact bone. Plated intact bones (TE/TD = 5.33 +/- 0.41) were significantly weaker than intact bones (TE/TD = 8.50 +/- 2.52; p less than 0.001). Our results substantiate the need for using polymethylmethacrylate and internal fixation in combination when prophylactically fixing pathologic lesions of this proportion.

Effects of bone graft and electrical stimulation on the strength of healing bony defects in dogs.

Autogenous cancellous bone graft alone or in combination with electrical stimulation is commonly employed yet there exists no conclusive data that the strength of the healing defect is actually modified. The authors examined three groups of paired canine femurs that were torsion tested to failure. Group I (in vitro): an intact femur was compared to a standard defect; Group II (in vivo): a defect alone was compared to a defect plus graft killed at eight weeks; Group III (in vivo): a defect plus graft was compared to a defect graft plus Osteostim (BGS Medical Corp., Milwaukee, Wisconsin) implantable stimulator killed at eight weeks. In Group I the defect decreased the average strength 45% (p = 0.005); in Group II the grafted defect decreased the strength 20% (p = 0.121); in Group III the defect graft plus electrical stimulation increased strength 4% (p = 0.669). At eight weeks, bone grafting, alone or with electrical stimulation did not statistically increase the torsional strength of the healing bony defect.