Biomedical subjects
Publications and source records attributed to H Kaufer.
A case in which only one sibling of an identical, HLA-B27 negative, twin pairing is affected by ankylosing spondylitis is reported. While endogenous variables may predispose certain populations to ankylosing spondylitis, the discordance illustrated in these seronegative monozygotic twins indicates that exogenous factors may certainly influence the development and course of this disease.
The spherocentric knee was designed as an intrinsically stable prosthesis to manage the problems of deformity, instability, and metaphyseal bone loss in joints too severely involved to use resurfacing arthroplasty. Follow-up information has been obtained on 58 of the first 82 knees requiring spherocentric arthroplasty. After an average eight-year followup period, the results are gratifying with respect to pain, ambulatory ability, deformity, and instability. The infection and reoperation rates of 5% and 15% seem satisfactory when one considers the severely disabled patient and pathologic conditions of the knee joint.
Arthrodesis remains the procedure of choice for salvage of an infected total knee arthroplasty in patients with relatively minor preprosthetic arthroplasty disability. Patients with very severe preprosthetic disability resulting from multiarticular disease or other systemic disease may be treated best by a resection arthroplasty. Systemic sepsis can be eliminated in almost all patients, and drainage can be eliminated in most. Those patients who find the stability of a resection arthroplasty inadequate for their needs can have a secondary arthrodesis performed with an intramedullary rod, which yields a high probability of success. External immobilization is not necessary. The advantages of a two-stage arthrodesis are that it is an elective procedure, performed in a limb free of sepsis. The patient has been psychologically prepared for the arthrodesis, and the two-stage procedure has a high probability of success. Neither the underlying diagnosis, nor the infecting organism, nor the type of infected prosthesis is a reliable predictor of success or failure of either a resection arthroplasty or a second-stage arthrodesis.
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In the treatment of equinovarus deformity of the foot in children with cerebral spastic paralysis, to supplement heel-cord lengthening, we split the posterior tibial tendon and transferred its posterior half laterally into the peroneus brevis tendon. Thirty-seven operations were performed on thirty-one hemiplegic, quadriplegic, and diplegic children who were followed for a mean of eight years postoperatively (range, four to fourteen years), at which time twenty-six of the thirty-one children were skeletally mature. There were thirty excellent, four good, and three poor results. The results did not deteriorate with time. Thirty-two of thirty-four children with good or excellent results had functioning dorsiflexors of the foot and were brace-free postoperatively. The children who had a poor result had recurrent deformity, but none had development of a calcaneal or calcaneovalgus deformity.
One hundred and one tibiotalar arthrodeses were performed using a single surgical technique that has not been previously reported. The average follow-up was ten years (range, two to twenty-five years). The rate of pseudarthrosis was 5 per cent, four to five times less than in other recent large reports. Pseudarthrosis occurred only in patients with a sensory deficit. Secure fusion was radiographically documented in 95 per cent and the functional clinical result was good to excellent in 90 per cent. The ideal fusion position was found to be neutral or slight equinus angulation, and varus-valgus angulation equal to that of the contralateral side. More than 7 degrees of varus angulation of the heel was associated with symptomatic lateral metatarsalgia in all feet in which it occurred. Radiographic measurement documented an average 85 per cent (11-degree) increase in postoperative tarsal motion. Neither symptoms nor function correlated with the degree of tarsal hypermobility.
UNLABELLED: Ten fresh human upper-extremity cadaver specimens were tested for the effect of residual angulation from simulated fractures of both bones of the forearm on the potential for range of rotation of the forearm and for limitations of pronation and supination specifically. Ten and 20-degree angulations for the radius and ulna, such as might be encountered in all reasonable clinical situations, were tested. Little significant loss of forearm rotation resulted from angulations of 10 degrees in any direction. With 20 degrees of angulation, there was statistically significant and functionally important loss of forearm rotation. CLINICAL RELEVANCE: A residual angulation of 10 degrees in mid-shaft fractures of the radius, ulna, or both bones of the forearm will not limit forearm rotation anatomically. Loss in the range of rotation can be expected with residual angeles of 20 degrees or more.
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We studied eighty-two consecutive spherocentric total knee arthroplasties with an average follow-up of four years (range, two to six years). All patients had either severe preoperative instability or deformity, or both. The over-all functional improvement and symptomatic relief were excellent. Knees with preoperative instability did as well as those with preoperative deformity that were stable. The knees with preoperative valgus deformity were the most likely to have postoperative wound problems or transient nerve palsy, while those with preoperative varus deformity were much more likely to have loosening. Postoperative limb alignment of 7 to 9 degrees of valgus angulation protected against lucency and loosening. No new cases of lucency or loosening appeared after two and one-half years. The infection rate was 4 per cent and the rate of failure due to loosening was 5 per cent. The over-all reoperation rate was 9 per cent. Nine patients (with eleven arthroplasties) died during the follow-up period.
Three patients had hematogenous infections caused by the same organism (as determined by identical antibiotic sensitivity profiles) in more than one joint. In each of the patients, the same infecting organism had also been recovered from a previous distant infection. Evidence that sepsis resulted from late hematogenous contamination is overwhelming. All three cases clearly had at least some late total joint infection which was not from organisms introduced at the time of total hip arthroplasty but from hematogenous contamination from a distant site occurring at a late date unknown to the surgeon. Patients with a total joint arthroplasty should probably have systemic antibiotic coverage to protect the prosthetic joint against hematogenous contamination from distant sites of infection and from potential bacteremia induced during medical or dental procedures.
The patella is an important functional component of the knee extension mechanism. It accounts for 13 to 30% of the knee extensors' moment arm. Functional deficits owing to patellectomy include decreased knee extension power, extension lag, instability, chronic effusion, decreased stance phase flexion, alteration of the path of instant flexion centers and decreased flexion range.
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The spherocentric knee is a non-hinged, intrinsically stable knee-joint prosthesis which allows controlled triaxial rotation and was designed specifically for use in severely deformed or grossly unstable knees. Biomechanical evaluation of the prosthesis implanted in fresh human cadaver limbs demonstrated highly favorable motion, stability, strength, deflection, and energy absorption characterists for the spherocentric prosthesis-bone assembly as compared with control cadaver knees. After an average follow-up of 25.5 months after the first twenty-five spherocentric arthroplasties, the clinical results were highly satisfactory and suggested that the spherocentric knee may be relatively resistant to the problems of wear debris, loosening, and breakage which have plagued other intrinsically stable knee-joint prostheses.
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Profound hypercalcemia associated with immobilization is rare. Hypercalcemic crisis occurring as a result of immobilization in which there was not a coexisting, contributing medical condition has not, to our knowledge, been reported previously. Failure to consider hypercalcemia as the source of progressive anorexia, nausea, vomiting, and irritability resulted in a respiratory arrest and nearly fatal outcome in the case of a 13-year-old boy one month after a simple femoral fracture. Therapy consisting of the intravenous administration of fluids and corticosteroids was successful in lowering the serum calcium level until mobilization could be accomplished. Review of previously reported cases emphasizes the difficulty in recognition and diagnosis of this unusual condition. Surgeons treating patients with fractures should be aware of this complication and familiar with its appropriate therapy.
It is obvious from the above that there are several independent mechanisms in the production of the various types of lumbar fractures. The details of these mechanisms must be fully understood in each case of lumbar vertebral injury. The cases reviewed in the present paper show that similar if not identical lumbar injuries can occur in car occupants wearing or not wearing lap belts at the time of the crash. Thus, cauxally relating a lumbar injury to the lap seat belt is in error. Only distraction injuries located between 1-2 and 1-4 with no evidence of either compression or anterior wedging can be causally related to a lap belt. Even some injuries with this typical confuguration have been observed in persons who were not belted (10). Thus, without knowledge of details of the crunch, lumbar fractures could mistakenly related to use of the lap belt. Thoraculumbar injuries have been senn in patients who were ejected from the car some time during the crash event. Relating the ejection event to the lumbar fracture must be done with great caution. As has been shown by Roaf (48) and by Kaufer and Hayes (33), the type and location of the lumbar spine injury can frequently and indicatory of load application. Other body injuries, or lack thereof, are often good clues to determine the point of load application causing lumbar injury. In addition, it has been recomended that additional details of the injury and of the accident be obtained for accuracy reporting of seat belt injuries.