Bone ingrowth into porous coated canine total hip replacements. Quantification by backscattered scanning electron microscopy and image analysis.

Bone ingrowth into titanium fiber mesh porous-surfaced canine total hip replacement prostheses was evaluated and quantified using a computer assisted image analysis system attached to a scanning electron microscope equipped with a back scattered electron detector. Excellent contrast between the bone, the porous metal and the soft tissues resulted in the backscatter mode, allowing easy differentiation of these components in real time by the image analysis based on gray scales. By three weeks the mean (+/- standard deviation) amount of bone ingrowth expressed as a percentage of porous layer measured 7.

Revision of nonseptic, loose, cemented femoral components using modern cementing techniques.

A series of 43 hips (41 patients) in which a cemented revision arthroplasty was performed for a symptomatic, nonseptic, loose (42) or broken (1) femoral component was reviewed clinically and radiographically. The operation was done using femoral components of contemporary design, a trochanteric osteotomy, a cement gun, and a PMMA femoral plug. The femoral compactor and water pic were used once they became available (36%).

Periprosthetic femoral fractures following total knee arthroplasty.

Supracondylar and distal femoral fractures involving total knee arthroplasties present a relatively new and challenging problem. The alignment of the total knee components prior to and subsequent to the fracture, as well as the patients' range of motion, symptoms, and level of function following their treatment, were investigated in 14 cases. Ten of the patients had nonoperative treatment.

Fractures of the acetabulum.

A critical analysis of the results reveals the following major factors in determining the outcome of an individual acetabular disruption: The damage to the acetabular articular surface, which is reflected by the pattern of fracture and its degree of comminution, impaction, and osteoporosis, and associated damage of the femoral head The adequacy of the reduction, which is reflected by intraoperative inspection and postoperative radiographs The associated complications of the fracture and treatment (e.g., avascular necrosis, sciatic palsy, and heterotopic ossification) We recommend principles of treatment of acetabular fractures comparable to those employed for most other displaced intraarticular fractures, namely an anatomic reduction, stable internal fixation, and early motion, to realize reproducibly optimal results.

Stability of acetabular fractures after internal fixation. A cadaveric study.

The rigidity of a transverse acetabular fracture in a laboratory cadaveric model immobilized by internal fixation was studied. On the application of a longitudinal load imposed on the fifth lumbar vertebra, four modes of displacement of the acetabular fracture were monitored by the use of variable impedance transducers. The rigidity of various combinations of lag screws and plates was assessed.

Experimental arthritis induced by intraarticular injection of allogenic cartilaginous particles into rabbit knees.

Human synovial fluid often contains small cartilaginous "wear particles." Previous in vitro experiments have indicated the potential involvement of these particles in the pathophysiology of arthritis. To determine whether this potential is realized under the conditions existing within joints, standard suspensions of lapine articular cartilage were injected intraarticularly into the knee joints of rabbits.

External and internal fixation of the pelvic ring.

From the basis of this experience an algorithm for the stabilization of virtually all types of pelvic ring disruption is provided which appears to outline suitable options in stabilization for virtually all types of pelvic ring fracture including those with acetabular disruption. Surgical complications have been sufficiently uncommon so that more widespread use of this protocol would appear to be justifiable. Nevertheless, the surgical techniques of internal fixation are formidable operations that should be undertaken only by those surgeons who possess appropriate training and experience.

External fixation of the pelvis.

During the past decade the useful classification and principles of management of the fractured pelvis have progressed rapidly. For the acute management the principal consideration is the control of severe intrapelvic hemorrhage. A protocol has been developed that combines the early application of external fixation with a closed reduction of the pelvic fracture.