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Biomedical subjects

R J Haddad

Publications and source records attributed to R J Haddad.

At least 55 records · Page 3Linked to original sources
PubMed1984

Joint position sense in total knee arthroplasty.

Seventeen postoperative total knee arthroplasty (TKA) patients were evaluated using two tests of knee joint position sense. Young controls and age-matched controls underwent identical tests. The TKA patients also underwent gait analysis, including foot switch stride analysis, and clinical evaluation using a standard scoring system. Results showed statistically significant decreases in joint position sense from young controls to old controls, and further significant decreases with joint disease; however, no further worsening was noted as a result of TKA. The abnormal gait parameters seen in TKA patients correlated as well with position sense as with clinical score. Strongest correlations were seen when a combined clinical and proprioceptive score was compared with gait parameters. In spite of alleviation of pain and correction of deformity, normal gait and function are not typically achieved after total knee replacement. Irreversible loss of joint proprioceptive function due to the disease process may be a major factor in the discrepancy between clinical and functional outcomes of total joint arthroplasty. Furthermore, loss of proprioception and the resulting abnormal gait patterns may place increased stress on components and contribute to loosening. In addition, an association between degenerative joint disease and decline in proprioception is suggested.

Adult↗
PubMed1984

Tissue reaction to a failed Bion hip prosthesis in a dog.

The tissue reaction in a dog to a failed constrained total hip replacement system with a Bion elastomer component was evaluated. The device consisted of Ti-6A1-4V alloy acetabular and femoral components connected with a Bion component. At necropsy the Bion component was found to have fractured. The tissue surrounding the Bion was granulomatous with numerous blackened regions. Histologically a severe chronic inflammatory response was present in the surrounding tissue with numerous giant cells and Bion laden macrophages.

Alkadienes↗
PubMed1984

Retrieval and analysis of intramedullary rods. A follow-up study.

From 1980 to 1983, 16 AO intramedullary femoral rods were retrieved and analyzed clinically, radiographically, and metallurgically. Cracking and/or fracture was observed in four of the 16 specimens. All cracks occurred at the point of maximum stress at the end of the slot. In two cases a structurally weaker weld zone coincided with this location. The weld zone and slot were also found to coincide in five of the uncracked rods. Two of the four cracked rods were removed because of pain, while only three of the 12 uncracked rods caused pain. Structural and material characteristics (i.e., the location of the weld at a point of maximum stress and significant variability in microstructure), rather than surgical technique or time in situ, were found to be responsible for the implant mechanical failures. Improvements should be made in fabrication techniques and material properties. For the present, careful assessment of a painful intramedullary rod and routine removal after healing are advisable.

Femoral Fractures↗
PubMed1983

Segmental spinal instrumentation in the management of fractures of the thoracic and lumbar spine.

Eleven cases of fracture of the thoracic and lumbar spine were treated with segmental spinal instrumentation (Luque rods). The majority of these injuries occurred in motor vehicular accidents or falls from a height and were usually associated with multisystem trauma. This method of instrumentation provided immediate rigid internal fixation, which obviated the need for postoperative orthoses, allowed easier nursing care and early ambulation, and facilitated rehabilitation of patients with spinal cord injury. At 13 months' average follow-up, there have been no instances of wire breakage, rod deformation, or deterioration of neurologic status. This favorable experience suggests that segmental spinal instrumentation should be considered as an alternative mode of spinal instrumentation in fractures of the thoracic and lumbar spine.

Accidents, Traffic↗
PubMed1983

Ambulatory function in total knee arthroplasty.

Through the use of gait analysis, this study attempts to characterize gait after total knee arthroplasty as a function of postoperative time to quantify the effectiveness of the surgery and to evaluate prostheses of several different designs. Gait analysis on 32 preoperative and 50 postoperative patients included measurement of velocity, cadence, stride length, and gait cycle. Postoperative data were collected at various intervals from 0.7 to 111 months after knee surgery (average postoperative time, 45.3 months). Linear regression analysis of velocity, cadence, stride length, gait cycle, and the ratio of contralateral to pathologic single limb support time as a function of postoperative time are reported with statistical error limits. Extrapolation of these results to zero postoperative time indicates that the patients who had had total knee arthroplasty had a slight improvement in all gait parameters compared to the preoperative control group. This was not statistically significant, however, except for cadence (P less than .05). Although velocity and stride length increased slightly toward more normal values with increased postoperative time, gait parameters at no time approached normal values.

Adult↗
PubMed1983

A biomechanical analysis of the etiology of tibia vara.

To elucidate the cause of tibia vara, finite element analysis of the proximal tibia was used to investigate the stresses occurring in the physeal plate during one-legged stance in 2- and 5-year-old children. A modification of the method of Kettlekamp and Chao was used to assign forces to the medial and lateral plateaus and lateral ligament. Stresses were calculated in the physeal plate for the two age groups as a function of degree of varus and body weight. Our results show that increasing varus resulted in increasing compressive stress in the medial tibial physis to a level seven times normal at 30 degrees of varus. Further, tensile stresses determined in the lateral tibial physis were increased above normal. Changes were more marked in the obese child and in the 5 year old. Using the data from Strobino et al. it appears that in the 2 year old 20 degrees of varus resulted in forces sufficient to retard growth. In the 5 year old, however, 10 degrees of varus resulted in borderline forces in a child of normal weight, but forces exceeding those necessary to retard physeal growth were calculated in the model of the obese child. Our data are consistent with the hypothesis that Blount's disease is primarily the result of the proximal tibial epiphysis responding to physical phenomena.

Biomechanical Phenomena↗
PubMed1983

Effect of articular disease and total knee arthroplasty on knee joint-position sense.

Joint proprioception in the human knee has been studied using two previously described tests. Threshold of detection of slow, constant, passive motion and ability to reproduce angles to which the knee was passively placed were accurately measured. A group of postoperative total knee arthroplasty (TKA) patients were examined. All patients also had documented articular disease in the unoperated knee. Results were compared to age-matched controls. In addition, a young control group was studied for comparison to both groups. A significant difference was seen between the young control group and the older control group in both tests performed. Age-matched controls and the postoperative patients demonstrated an even greater difference. There was, however, no difference between the operated and unoperated knee among the TKA patients. It is concluded that joint proprioception declines to some degree with normal aging. A more marked decline is associated with degenerative joint disease. Total joint replacement, however, did not lead to a further decrease in sensation.

Age Factors↗
PubMed1983

Femoral head stresses following cortical bone grafting for aseptic necrosis. A finite element study.

A two-dimensional finite element model was used to compare the femoral head stress distribution of an intact femur with that of a femur following core biopsy and biopsy with cortical grafting. There was a decrease in superior and lateral femoral head stresses of up to 50% by an incorporated and properly placed cortical graft. Core biopsy and cortical grafting short of the subchondral plate produced stress-concentrating effects. A medially placed cortical graft did not stress-relieve the superolateral femoral head. Thus, if cortical grafting is to be undertaken, the graft should extend from the lateral cortex to the subchondral plate, transfixing the length of the necrotic segment. Because of deleterious effects on femoral head stress distribution, core biopsy without cortical grafting should be discouraged or only very cautiously used.

Bone Transplantation↗
PubMed1983

A quantitative histologic study of osteoporosis produced by nutritional secondary hyperparathyroidism in dogs.

Nutritional secondary hyperparathyroidism (NSH) was induced in adult beagle dogs through nutritional control by a diet high in phosphorus (1.20%) and low in calcium (0.12%). A control group was fed a diet containing 0.42% phosphorus and 0.54% calcium. A statistically significant increase in iPTH level was observed at ten and 20 weeks. The femoral heads of experimental (NSH) animals showed increased osteoclastic activity and an approximately 20%-30% reduction in volume fraction cancellous bone. No abnormal osteoid seam was found in the cancellous bone of the experimental animals, and no statistically significant differences were observed in either the calcium-to-phosphorus or mineral-to-matrix ratios of the bone tissue for the two groups. Data obtained from histologic sections on the number of trabecular bone intercepts per unit length and thickness of trabeculae in the femoral head indicated a uniform, rather than specific loss of bone mass in the experimental sections. Histologic sections from the proximal femoral shaft revealed increased endosteal and periosteal diameters in the experimental group compared with the control group.

Animals↗
PubMed1983

Fractured coracoid process in acromioclavicular dislocations. Report of four cases and review of the literature.

Acromioclavicular (AC) dislocation with a concomitant coracoid process fracture occurs infrequently. This fracture should be suspected with all AC dislocations occurring in the first three decades of life. An axillary lateral radiograph or tomogram often is needed to detect the fracture. Surgical treatment can produce good results, but equally satisfactory function with minimal residual cosmetic deformity may be achieved by nonsurgical measures.

Acromioclavicular Joint↗
PubMed1982

Stress distribution in the proximal femur after surface replacement: effects of prosthesis and surgical techniques.

The increasing number of reported femoral neck fractures following surface replacement indicates a potentially serious problem in this procedure. A comparison of the stress levels in the proximal femur before and after hip surface replacement was made using the finite element technique. A proposed surgical bone graft procedure utilizing a strut of cortical bone placed through the femoral head into the neck to help support the surface replacement was also studied as an adjunct for use in avascular necrosis. The findings indicate that stress magnitudes and distributions in the proximal femur are markedly altered after surface replacement when compared to a femur without a prosthesis. Stress levels in the femoral head with surface replacement were found to be significantly lowered suggesting future problems with stress shielding. Lateral neck stresses were found to be equal to or greater than stress levels in the femur without a prosthesis. Stress orientation in the femoral neck is also markedly altered. Surface replacement design and recommended surgical positioning were important variables in determining stress levels. Femoral neck stresses were found to be significantly lowered for all designs of surface replacement when the bone graft modification was utilized. The results of this study explain the major mechanisms of failure of the femoral component. The proposed bone graft modification is demonstrated by the finite element model to decrease the possibility of femoral neck fracture.

Femur↗
PubMed1982

Third-generation beta-lactam antibiotics for treatment of orthopedic infections.

Third-generation beta-lactam antibiotics are effective against a wider range of microorganisms than are older antibiotics. Cefotaxime, moxalactam, cefoperazone, ceftizoxime, ceftazidime, cefsulodin, and ceftriaxone were used to treat 102 patients hospitalized with orthopedic infections. Sensitivity of the pathogens to the antibiotic used was established in all cases. Patients allergic to penicillin were given either moxalactam or ceftazidime. Pathogens were eradicated in all but six instances, five of which were Pseudomonas aeruginosa. Four of these developed resistance during therapy. Only three patients had clinical responses that were less than satisfactory. No serious adverse reaction occurred, and no allergic reactions developed. This new class of antibiotics is thus safe and effective as the sole therapeutic agent for many orthopedic infections, including those that require long periods of treatment.

Adolescent↗
PubMed1975

Hallux valgus and metatarsus primus varus treated by bunionectomy and proximal metatarsal osteotomy.

Sixteen feet with hallux valgus and metatarsus primus varus have been treated by excision of the exostosis of the first metatarsal head, advancement of the medial capsule and the abductor hallucis, release of the lateral capsule and adductor tendon, and open-wedge osteotomy at the base of the first metatarsal inserting a bone graft. During a three-year period ther have been no nonunions of the osteotomy, and satisfactory maintenance of the corrections has occurred. This method is preferred over distal metatarsal osteotomy.

Bone Transplantation↗