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Biomedical subjects

John J Callaghan

Publications and source records attributed to John J Callaghan.

63 records · Page 4Linked to original sources
PubMed2002

Posterior cruciate-retaining modular total knee arthroplasty: a 9- to 12-year follow-up investigation.

Between November 1988 and January 1991, 101 press-fit condylar (PFC; Johnson & Johnson, Raynham, MA) posterior cruciate-retaining total knee arthroplasties were performed in 75 patients. All tibial components were modular metal-backed, and all patellar components were all-polyethylene. All living patients were evaluated at an average 10.5 years (range, 9.5-11.8 years). Only 1 knee required revision (at 11.1 years after the procedure), and only 1 other knee had evidence of radiographic failure. The average range of motion was 1 degrees (range, 0 degrees -10 degrees ) to 110 degrees (range, 86 degrees -130 degrees ). At 10 years of follow-up, the probability of prosthesis survival was 100%, and at 12 years, the probability of prosthesis survival was 93.3% (endpoint defined as revision for any reason).

Aged↗
PubMed2002

Tibial post impingement in posterior-stabilized total knee arthroplasty.

Reports of posterior-stabilized total knee replacements have shown excellent clinical success. However, tibial post-femoral cam impingement has been seen in modular component retrievals. This finding has been associated with transmission of rotational forces to the modular tray-polyethylene interface with subsequent backside polyethylene wear and the development of osteolysis. Femoral cam-tibial post designs that allow hyperextension and limit rotational constraint may minimize this impingement. Technical considerations including the avoidance of femoral component flexion and posterior tibial slope will minimize anterior tibial post impingement.

Arthroplasty, Replacement, Knee↗
PubMed2002

Choices and compromises in the use of small head sizes in total hip arthroplasty.

Observation cohort studies, a sliding-distance-coupled finite element model, and an expanded finite element model that simulates dislocation were used to evaluate the benefits and compromises associated with the use of smaller femoral heads in the total hip arthroplasty construct. Wear studies of total hip arthroplasty cohorts showed less polyethylene wear and less deleterious effects of third body debris when smaller femoral head sizes were used. The sliding-distance-coupled finite element model findings were corroborated by these clinical wear studies. The dislocation model predicted the increased propensity for dislocation when smaller modular head femoral components were used in the cohort studies. Impingement is not the only contributor to frank dislocation. The dislocation model explicitly defined the range of motion changes from impingement to dislocation, and the resisting moment changes between construct designs.

Adult↗
PubMed2002

Local head roughening as a factor contributing to variability of total hip wear: a finite element analysis.

Large inter-patient variability in wear rate and wear direction have been a ubiquitous attribute of total hip arthroplasty (THA) cohorts. Since patients at the high end of the wear spectrum are of particular concern for osteolysis and loosening, it is important to understand why some individuals experience wear at a rate far in excess of their cohort average. An established computational model of polyethylene wear was used to test the hypothesis that, other factors being equal, clinically typical variability in regions of localized femoral head roughening could account for much of the variability observed clinically in both wear magnitude and wear direction. The model implemented the Archard abrasive/adhesive wear relationship, which incorporates contact stress, sliding distance, and (implicitly) bearing surface tribology. Systematic trials were conducted to explore the influences of head roughening severity, roughened area size, and roughened area location. The results showed that, given the postulated wear factor elevations, head roughening variability (conservatively) typical of retrieval specimens led to approximately a 30 degrees variation in wear direction, and approximately a 7-fold variation in volumetric wear rate. Since these data show that randomness in head scratching can account for otherwise-difficult-to-explain variations in wear direction and wear rate, third-body debris may be a key factor causing excessive wear in the most problematic subset of the THA population.

Acetabulum↗
PubMed2002

Osteolysis associated with a cemented modular posterior-cruciate-substituting total knee design : five to eight-year follow-up.

BACKGROUND: Most intermediate and long-term studies of cemented posterior-cruciate-substituting total knee prostheses were performed with nonmodular tibial components. The purpose of this study was to evaluate the intermediate-term results of posterior-cruciate-substituting total knee arthroplasties in which a cemented modular tibial component had been used, with a particular focus on evaluating the prevalence of radiographic osteolysis. METHODS: Between 1992 and 1995, 176 consecutive primary total knee arthroplasties with use of the Insall-Burstein II system were performed in 134 patients at our institution. A modular metal-backed tibial component was inserted in 145 knees, and an all-polyethylene tibial component of the same design was inserted in thirty-one. Standard-terminology questionnaires were completed or Knee Society and The Hospital for Special Surgery scores were determined preoperatively and at the time of final follow-up, at an average of 6.4 years (range, 5.0 to 7.9 years). Initial postoperative radiographs were compared with those made at the time of final follow-up to assess component position, wear, radiolucent lines, and osteolysis. RESULTS: Ninety-two patients (128 knees) treated with the modular tibial component were alive at the time of final follow-up. No patient was lost to follow-up. Radiographs were available for 105 knees (82%). Three knees had been revised because of instability or infection; none had been revised because of loosening or osteolysis. The mean Knee Society clinical and functional scores were 85 points (range, 41 to 100 points) and 79 points (range, 30 to 100 points), respectively, at the time of final follow-up. According to The Hospital for Special Surgery score, 94% of the knees had a good or excellent result. Knee flexion averaged 113 degrees (range, 90 degrees to 130 degrees ) at the time of final follow-up. Osteolysis was present in seventeen (16%) of the knees with radiographic follow-up. Osteolysis did not develop in any knee in which an all-polyethylene tibial component had been used. Two knees (in one patient) were revised because of osteolytic lesions found at the time of follow-up for the study. Both of these knees had anterior wear of the tibial post due to impingement and backside tibial polyethylene wear. CONCLUSIONS: Modular Insall-Burstein II total knee prostheses were found to function well after five to eight years of follow-up. However, the high prevalence of osteolysis in patients who had good or excellent clinical scores is worrisome. Particular attention should be paid to preventing flexion of the femoral component, posterior slope of the tibial component, or hyperextension of the knee when posterior-cruciate-substituting total knee arthroplasty is performed. We also recommend routine follow-up radiographs after all total joint arthroplasties to detect asymptomatic osteolytic changes.

Aged↗
PubMed2002

Minimum ten-year follow-up of cemented total hip replacement in patients with osteonecrosis of the femoral head.

Between November 1970 and September 1984 the senior author performed fifty-three consecutive total hip arthroplasties with cement in forty-one patients with the diagnosis of osteonecrosis of the femoral head. Five hips in three patients with failed renal transplants requiring chronic hemodialysis were excluded. At the time of final review, a minimum of ten years after the procedure, twenty-one patients (twenty-eight hips) were living, fifteen patients (eighteen hips) had died, and two patients (two hips) were lost to follow-up. A minimum ten-year follow-up radiograph was obtained on twenty-two (79%) of the hips in surviving patients. During the follow-up period 17.4% of hips (eight hips) required revision: 13.0% (six hips) for aseptic loosening, 2.2% (one hip) for sepsis, and 2.2% (one hip) for recurrent dislocation. All eight revisions occurred in patients living at time of final review, giving a revision prevalence of 22.9% (17.1% for aseptic loosening, 2.9% for sepsis, and 2.9% for recurrent dislocation) in patients surviving ten years. The prevalence of revision of the femoral component for aseptic loosening was 6.5% (three hips) for all hips and 9.1% (three hips) in patients surviving at least ten years. The prevalence of femoral aseptic loosening, defined as those components revised for aseptic loosening and those that demonstrated definite or probable radiographic loosening, was 13.0% (six hips) for all hips and 28.6% (six hips) for hips with at least ten-year radiographic follow-up. The prevalence of revision of the acetabular component for aseptic loosening was 13.0% (six hips) for all hips and 18.2% (six hips) in patients surviving at least ten years. The prevalence of acetabular aseptic loosening was 15.2% (seven hips) for all hips and 29.2% (seven hips) for hips with at least ten-year radiographic follow-up. In patients with osteonecrosis of the femoral head survivorship was significantly inferior to that in the senior author's overall patient population with regard to revision for aseptic loosening (p=0.019), revision for acetabular loosening (p=0.01), revision for femoral loosening (p=0.008), and aseptic femoral loosening (p=0.004). Survivorship to aseptic acetabular loosening was not significantly different (p=0.32). Young age at the time of surgery significantly increased the risk of subsequent component loosening (p<0.008) and revision due to aseptic loosening (p<0.002). These findings demonstrate the relatively poor durability of cemented total hip arthroplasty in patients with osteonecrosis of the femoral head as compared to patients with other diagnoses and suggest that the younger age in this patient population compromises results.

Adolescent↗
PubMed2002

Androgen receptors in human synoviocytes and androgen regulation of interleukin 1beta (IL-1beta) induced IL-6 production: a link between hypoandrogenicity and rheumatoid arthritis?

OBJECTIVE: To investigate the hypothesis that synoviocytes possess androgen receptors (AR) that could be modulated by the non-aromatizable androgen, dihydrotestosterone (DHT), resulting in altered levels of inflammatory cytokines. METHODS: Using molecular analyses of AR in combination with the multiprobe ribonuclease protection assay and ELISA, we investigated the presence of AR and the effect of DHT on interleukin 1beta (IL-1beta) induced expression of the IL-6 superfamily of cytokines in synoviocytes. RESULTS: Our studies corroborate the presence of AR in synoviocytes. DHT exerts a suppressive effect on IL-1beta induced IL-6, macrophage-colony stimulating factor (CSF), and granulocyte-CSF production by synoviocytes. This modulatory effect is exerted at both the transcriptional and translational level; 17beta-estradiol, at high concentrations, had a stimulatory effect. CONCLUSION: The identification of functional AR in synoviocytes and the modulatory effect of DHT on the inflammatory process in the joint suggest a direct link between hypoandrogenicity and rheumatoid arthritis (RA) disease status. Understanding the complex regulation of inflammatory cytokines by hormones may contribute to the development of new therapeutic targets for clinical intervention in RA.

Adolescent↗