Heterotopic bone in hip arthroplasties. Cemented versus noncemented.

Sixty-six hip arthroplasties in 55 patients were reviewed to specifically study cemented versus noncemented procedures, as related to heterotopic bone formation (HBF). Other factors considered included the type of arthroplasty, surgical approaches, preoperative and postoperative medicines, preoperative predisposing diagnoses, range of motion, and pain. The overall percentage of heterotopic ossification was 64%. There was no significant difference between cemented (67%) and noncemented (55%) procedures. Except for an increased percentage (80%) of ossification after a trochanteric osteotomy, there were no significant differences between the three reviewed surgical approaches. Male osteoarthritics had the highest overall HBF. Eighty percent of patients who previously had developed HBF also did so with a contralateral hip surgery. Surprisingly, all patients with gout (100%) developed HBF. Acetylsalicylic acid used prophylactically for anticoagulation had no significant effect. Resurfacing arthroplasty procedures accounted for half of the severe grades of HBF. A decreased range of motion occurred with more severe grades of HBF.

Perioperative blood loss associated with total knee arthroplasty. A comparison of procedures performed with and without cementing.

We reviewed the cases of thirty-four patients (thirty-eight knees) in whom prostheses with an identical design were used for primary total knee arthroplasty, and we compared the perioperative blood loss between the eleven knees in which cement was used and the twenty-seven knees in which cement was not used. The patients who had an uncemented prosthesis had a significantly greater mean blood loss, both intraoperatively (p less than or equal to 0.05) and during each subsequent eight-hour interval on the first postoperative day (p less than or equal to 0.05). The total for the forty-eight-hour postoperative collection also was greater (p less than or equal to 0.01), as was the cumulative loss for the entire study (p less than or equal to 0.01). When patients who had rheumatoid arthritis and osteoarthrosis were considered separately, the results were similar; that is, there was a significantly greater total postoperative blood loss in each of the two groups when cement was not used (p less than or equal to 0.025). A minimum postoperative hemoglobin concentration of ninety-five grams per liter was maintained; a greater percentage of patients (sixteen of twenty-seven) in whom cement was not used needed a transfusion as compared with two of eleven in the group in whom cement was not used (p less than or equal to 0.025), and they also needed more packed red-blood cells (1062 compared with 750 milliliters) (p less than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A phalangeal fracture model--quantitative analysis of rigidity and failure.

Nine types of internal fixation techniques were tested in 4-point bending using a pig metacarpal model for phalangeal fractures. Levels of bending rigidity and bending moments at failure were determined, and the modes of failure are described. Plate and screw fixation afforded the greatest rigidity, and epiphyseal fractures occurred, leaving intact the test section. Flexible wire loop fixation failed by wire cutting into bone when a square knot was used. Twisted wire unraveled when placed in tension. Depending on the fracture type and the wire placement. Kirschner wires failed either by slipping in the bone, twisting in the bone cortex, or bending at the bone cortex interface. Rigidity varied widely depending on the way in which the wires were employed.