Late radial head dislocation with radial head fracture and ulnar plastic deformation.

Type II Monteggia lesion equivalents produced by plastic deformation of the ulna are rare. Radial head fractures in skeletally immature patients are also uncommon. We report a late presentation of a Type II Monteggia equivalent injury with a fracture of the radial head and neck and plastic deformation of the ulna in an 11-year-old boy. The radial head was located on the initial injury radiographs and subsequently dislocated in a posterior direction. The radial head fracture was misdiagnosed as a coronoid fracture at presentation. The plastic deformation of the ulna was diagnosed several weeks after the injury when the dislocation was first noted. Magnetic resonance imaging was used to establish the diagnosis of a radial head fracture at the same time. The patient was treated successfully with an open reduction and internal fixation of the radial head combined with a dorsal closing-wedge ulnar osteotomy.

Current status of trochanteric reattachment in complex total hip arthroplasty.

UNLABELLED: A study was done to determine if cable fixation devices of more recent design were associated with a higher success rate and lower incidence of complications compared with early cable devices. Beginning in 1997 a cable plate device was used in an attempt to restore abductor function more consistently in complex total hip arthroplasties. Cobalt-chrome cables through holes in a trochanteric cable plate with two or more transversely oriented cables at or below the lesser trochanter were used in order to resist migration of the trochanteric fragment better. Other component features included instrumentation that allowed provisional fixation and measurement of the tension in the cables so that cables could be tightened and retightened sequentially to insure a minimum of 80 inch-pounds of tension in all cables before final crimping. Minimum 2-year followup was obtained in 42 patients who had complex arthroplasties (trochanteric nonunions and reattachment to structural grafts) in which such a device was used. Clinical and radiographic results were compared with a series of patients with similar indications in whom wire or and earlier-generation trochanteric cable fixation devices were used. The cable plate of a more recent design was associated with a possible trend for a lower incidence of limp, use of assistive walking devices, dislocation, and abductor weakness and significant decrease in the incidence of breakage and trochanteric nonunion. LEVEL OF EVIDENCE: Therapeutic study, Level III-1 (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Avoidance and management of neurovascular injuries in total hip arthroplasty.

Neural injuries that occur after total hip arthroplasty (THA) can be classified as involving either the central nervous system or peripheral nerves. Central nervous system changes after THA may be attributed to increased appreciation of fat embolism syndrome associated with THA. Certain maneuvers such as impacting the acetabulum, femoral reaming, and cement pressurization can force marrow fat into the venous system. When there is an associated right to left shunt, paradoxical embolization can occur, which may account for previously unexplained cases of confusion and mental status changes after surgery. Peripheral nerve injuries are rare and can involve either distant sites or nerves in the immediate vicinity of the hip joint. Upper extremity nerve injuries are usually associated with patient positioning. Sciatic nerve injury is the most common nerve injury following THA. In comparison, femoral nerve injury is much less common and is associated with an anterior approach. Diagnosis is often delayed, and the prognosis is generally better than with sciatic nerve injury. The superior gluteal nerve is at risk during the direct lateral approach. Obturator nerve injury is the least common type of injury and has the least functional consequence. It can present as groin or inguinal pain. Vascular injuries are less common but more immediately life threatening. The mechanisms of vascular injury include occlusion associated with preexisting peripheral vascular disease and vascular injury during removal of cement during screw fixation of acetabular components, cages, or structural grafts. Perioperative assessment should include vascular evaluation of patients with absent pulses, previous vascular bypass surgery, or dysvascular limbs. A CT scan should be considered when cement or components extend medially into the pelvis.

Revision total knee arthroplasty: fixation with modular stems.

The number of revision total knee replacements continues to increase annually. To date, much of the literature has focused on the performance of titanium revision systems. The primary aim of the current study was to review the mid term results of a contemporary revision knee system, with alternative design features. Ninety-one consecutive patients having aseptic revision total knee arthroplasty with one, modular all-cobalt chrome stemmed revision knee system using hybrid stem fixation were studied prospectively. Eighty-nine revisions in 84 patients were reviewed at a mean of 5.9 years (range, 4.1-8.6 years). Significant improvements in pain scores (15 +/- 14 to 38 +/- 14), function (40 +/- 24 to 53 +/- 29), range of motion (88 degrees +/- 23 degrees to 98 degrees +/- 18 degrees ), and total Knee Society score (85 +/- 40 to 132 +/- 40) were seen at followup. Five patients had revision surgery, with a Kaplan-Meier survivorship of 93.5% at 8.6 years. Intermediate results support the use of cobalt chrome components and hybrid cement fixation; however, this fixation in combination with high articular constraint requires continued monitoring.