Primary cup stability in THA with augmentation of acetabular defect. A comparison of healthy and osteoporotic bone.

Background Context: Reconstruction of acetabular defect has been advocated as standard procedure in total hip arthroplasty. The presence of bony defects at the acetabulum is viewed as a cause of instability and acetabular wall augmentation is often used without proper consideration of surrounding bone density. The initial cup-bone stability is, however, a challenge and a number of studies supported by clinical follow-ups of patients suggested that if the structural graft needs supporting more than 50% of the acetabular component, a reconstruction cage device spanning ilium to ischium should be preferred to protect the graft and provide structural stability.

Factors influencing initial cup stability in total hip arthroplasty.

Background: One of the main goals in total hip replacement is to preserve the integrity of the hip kinematics, by well positioning the cup and to make sure its initial stability is congruent and attained. Achieving the latter is not trivial.

Methods: A finite element model of the cup-bone interface simulating a realistic insertion and analysis of different scenarios of cup penetration, insertion, under-reaming and loading is investigated to determine certain measurable factors sensitivity to stress-strain outcome.

Optimisation of the posterior stabilised tibial post for greater femoral rollback after total knee arthroplasty--a finite element analysis.

Femoral rollback after total knee arthroplasty (TKA) is necessary for flexion beyond 90-100 degrees. Femoral rollback in posterior cruciate substituting TKA occurs as a result of the interaction between the femoral cam and tibial post. The geometric design of the cam post mechanism determines the kinematics of rollback.

Short-term outcome of preterms in two neonatology units in Al-qassim, saudi arabia.

Objective: A follow-up study, to compare the short-term outcome of preterms, in two hospitals in Al Qassim region, Saudi Arabia.

Methods: Preterms admitted in two hospitals, 47 in hospital A and 36 in hospital B, were followed from admission until one month after discharge. Preterms were compared on gestational age, birth weight, birth head circumference and length of stay.

Clinical evaluation of disabled children in Al-Qassim region, Saudi Arabia.

Objective: The study was conducted as part of an overall evaluation for an outreach program to evaluate the clinical status of all the participating children, identify management problems, if any, and offer relevant recommendations.

Methods: All the participating children were subjected to a detailed clinical evaluation using a structured questionnaire developed for the purpose. The subjects of this study were registered in the Center for Disabled Children in Buraidah and Unaizah, Al-Qassim region, Kingdom of Saudi Arabia.

Femoral shaft fracture after hip arthroplasty: a system for classification and treatment.

Twenty-one consecutive cases of femoral shaft fracture after hip arthroplasty treated at the University of Illinois affiliated hospitals were reviewed. Adequate follow-up and radiographs were available for 19 patients. The length of follow-up after fracture ranged from 2 to 13 years, with a mean of 3.

Inhibition of particulate debris-induced osteolysis by alendronate in a rat model.

A rat model was used to study the efficacy of alendronate therapy in inhibition of particle-induced periprosthetic osteolysis. A prosthesis was simulated by inserting a cylindrical polymethylmethacrylate plug into the distal femur of 24 rats allowing the plug to communicate with the joint space. Intra-articular injections of irregularly-shaped ultra-high molecular weight polyethylene particles of 20-200 pm in diameter were administered at 2-week intervals.

Proprioception after arthroplasty: role of the posterior cruciate ligament.

To test the hypothesis that retaining the posterior cruciate ligament during total knee arthroplasty helps preserve the threshold of proprioceptive sensation, a machine was designed that permitted direct measurement of passive angular deflection from a resting point to the threshold of patient perception. Sixty patients with unilateral primary total knee arthroplasties were evaluated; 30 with posterior cruciate ligament retaining prostheses and 30 with posterior cruciate ligament substituting prostheses. All patients had a minimum postoperative followup of 1 year, a good or excellent result as defined by the Hospital for Special Surgery Knee Score, and no evidence of peripheral neuropathy.

Misoprostol Inhibits Polymethylmethacrylate-Stimulated Lysosomal Degranulation and IL-1 Release from Neutrophils.

Endoprosthetic orthopedic implants may loosen over time. The mechanism of this loosening process remains poorly understood. Wear debris sloughed from bone cement (polymethylmethacrylate, PMMA) and orthopedic implant materials (metal, ultrahigh-molecular-weight polyethylene) may stimulate inflammatory responses in phagocytic cells which populate the bone-implant interface (synovial-like membrane).

Treatment of moderate to severe slipped capital femoral epiphysis with extracapsular base-of-neck osteotomy.

Extracapsular base of femoral neck osteotomy was performed in 36 hips with moderate to severe slipped capital femoral epiphysis (SCFE). Follow-up ranged from 2 to 24 years (average 9 years). According to modified Southwick's criteria, 90% of the hips had excellent or good result.

Increased superoxide anion production in polymorphonuclear leucocytes on exposure to isobutyl-2-cyanoacrylate.

Alkyl-2-cyanoacrylates have been employed in a variety of surgical procedures, although the pathophysiological basis for their cytotoxicity has not been resolved. Previous reports indicated that leucocytes infiltrate the site of cyanoacrylate application in situ. Consequently, human polymorphonuclear leucocytes were treated with 0-200 mM cyanoacrylate isobutyl-2- and superoxide anion radical production, lactate dehydrogenase release, and intracellular reduced glutathione content were quantitated following this treatment.

Biochemical changes in knee joint articular cartilage after cemented prosthetic hip hemiarthroplasty in dogs.

Biochemical changes in the distal femoral articular cartilage (knee joint) after cemented prosthetic replacement of the femoral head were determined. Femurs from dogs (n = 10) that had undergone cobalt-chromium prosthetic hip hemiarthroplasty (6-8 months postoperatively) were analyzed for articular cartilage lipids in the distal femur. The quantity of phosphatidylserine increased from 0.

Healing potential of experimental meniscal tears in the rabbit. Preliminary results.

This study assessed the healing potential of longitudinal or transverse incisions in the peripheral, central, and inner rim regions of rabbit medial menisci. Longitudinal and transverse incisions were made in 48 male New Zealand white rabbits. The incisions were either repaired with sutures or left open.

Polymorphonuclear leukocyte degranulation with exposure to polymethylmethacrylate nanoparticles.

Polymethylmethacrylate (PMMA) is clinically employed in a wide range of orthopaedic procedures. The etiology of the inflammatory reaction of recipient tissues to PMMA remains unresolved. Classically, polymorphonuclear leukocytes (PMNs) release cytoplasmic lysosomal granules when exposed to a variety of proinflammatory stimuli.

Clinical and motion studies of the Bateman bipolar prosthesis in osteonecrosis of the hip.

Forty-seven hips in 38 patients with femoral head osteonecrosis were reviewed for a mean follow-up period of 2.6 years. The average preoperative Harris hip score was 24.

Bateman hemiarthroplasty component disassembly. A report of three cases of high-density polyethylene failure.

Mechanical failures occurred in three Bateman bipolar hemiarthroplasties in two patients. In all three occurrences, the disassembly of the bipolar prosthesis was caused by fracture of the polyethylene liner of the bipolar acetabular component. This caused the 22-mm head of the femoral component to separate and unlock from the acetabular component.

Detection of musculoskeletal infection with the indium-III leukocyte scan.

Indium-111-labeled leukocyte scans were performed on 39 patients with suspected musculoskeletal infections to assess the usefulness of this study in detecting bone and joint infections. Results of these scans, as well as results of technetium-99m bone scans, were correlated with the patients' final diagnoses. The indium scan had an overall sensitivity of 77%, a specificity of 69%, and an accuracy of 72%.

The effect of adjunctive methylmethacrylate on failures of fixation and function in patients with intertrochanteric fractures and osteoporosis.

In a retrospective review of eighty-two intertrochanteric fractures (twenty-nine stable and fifty-three unstable) in seventy-nine elderly, debilitated patients with associated advanced osteoporosis (Grade III or less by the system of Singh et al.), fifty-six were available for follow-up: twenty-eight that had been treated at the University of Illinois with an approximately anatomical reduction and compression-screw fixation and twenty-eight (in twenty-seven patients) that had been treated at the University of Chicago with an approximately anatomical reduction, compression-screw fixation, and adjunctive methylmethacrylate bone cement in the head-neck fragment. Follow-up analysis after an average of thirty-four months for the group that had augmentation with cement and an average of twenty-six months for the uncemented group showed that for the eighteen stable fractures that could be followed the rates of complications of fixation were the same in the two groups, while for the thirty-eight unstable comminuted fractures that were followed the rate of complications of fixation was lower when adjunctive methylmethacrylate cement was used.

Can carbon fiber implants substitute for collateral ligament?

The biomechanic and histologic changes following replacement of the medial collateral digit of the knee with carbon fiber filament prostheses of varying diameters were studied in young rabbits. Biomechanic testing showed changes with time in the mode of failure and force to failure of the replacements, but the initial differences in the force to failure of the three diameter groups diminished over the 12-week experimental period. Histologic studies with both light and electron microscopy revealed resorption of the carbon fibers and replacement by fibrosed ligaments.

Early mobilization of rabbit medial collateral ligament repairs: biomechanic and histologic study.

The postoperative management of repaired medial collateral ligaments is controversial. There are proponents for either early mobilization or immobilization. To contribute to an understanding of the issues, 24 adult Dutch rabbits were divided into four groups and a comparative study was made of their incised medial collateral ligaments, contrasting early immobilization with mobilization at three and six weeks.

A comparison between arthrotomy and irrigation and multiple aspirations in the treatment of pyogenic arthritis: a histological study in a rabbit model.

Staphylococcus aureus pyogenic arthritis was produced in a group of eight rabbits. After 24 hours, all rabbits were treated with systemic procaine and benzathine penicillin for five days. Four rabbits were treated with daily aspiration, and four rabbits were treated with arthrotomy and irrigation.

An apparatus for measuring the load-displacement and load-dependent kinematic characteristics of articulating joints-application to the human ankle joint.

An apparatus is described which is capable of measuring the load-displacement characteristics as well as determining the loci of centers of rotation of articulating joints. The apparatus employs a floating head which permits the axis of rotation to coincide with the position of minimum joint resistance, thus eliminating non-physiological rotations at the joint. The coupled loads are also measured, thus providing an accurate description of the joint structural characteristics.

Acrolysis in pachydermoperiostosis. Primary or idiopathic hypertrophic osteoarthropathy.

A 45-year-old black woman was admitted for correction of an equinus deformity of the right lower extremity that resulted from shortening of the Achilles tendon. She exhibited classic findings of pachydermoperiostosis, including clubbing of the digits, periosteal new bone formation, and hypertrophy of skin and its adnexa, associated with several facial acne. In addition, she showed excessive resorption of distal phalanges of the hands and feet, a finding heretofore unreported in pachydermoperiostosis, to our knowledge.