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Biomedical subjects

Kevin J Mulhall

Publications and source records attributed to Kevin J Mulhall.

At least 19 recordsLinked to original sources
PubMed2006

Socioeconomic issues and demographics of total knee arthroplasty revision.

UNLABELLED: Despite rising numbers of total knee arthroplasty revision (TKAR) procedures there remains a paucity of information regarding the relationships between total knee arthroplasty failure and socioeconomic and educational status, demographics, general health and functional disability. We performed a multicenter prospective study of 290 consecutive TKAR patients in order to determine whether they differed from the population they were drawn from in terms of socioeconomic or educational status, race or gender. Secondary aims were to establish the relative comorbid status of this population, social supports and their general health status compared to national norms and their modes of failure. Our cohort consisted of 137 males and 153 females with a mean age of 68.6 years (range, 34-85 years), substantial overall functional disability according to the SF-36 and a large average number of comorbidities at baseline. We found a relative overrepresentation of patients of comparatively low socioeconomic and educational status and also of Caucasian patients in the TKAR population. This large prospective investigation demonstrates demographic features associated with TKA failure and provides a platform for further investigations on the effect demographic characteristics have on the outcomes of TKAR. LEVEL OF EVIDENCE: Prognostic Study, Level II (Lesser quality prospective study). See Guidelines for Authors for a complete description of the Levels of Evidence.

Adult↗
PubMed2006

Current etiologies and modes of failure in total knee arthroplasty revision.

UNLABELLED: Although total knee arthroplasty is a very effective intervention and increasing in prevalence, failures do occur. We studied patients presenting for total knee arthroplasty revision to determine any modifiable causes of failure, both short and long term, and where future efforts should be directed to reduce the incidence of failure. A multicenter prospective observational cohort study of 318 consecutive patients, with minimum 1 year follow-up, undergoing total knee arthroplasty revision was performed. Associations between modes of failure were also assessed. The mean time from primary procedure to total knee arthroplasty revision was 7.9 years. Many patients (64.4%) had more than one cause of failure. Thirty-one percent of patients were early (< 2 years) failures at a mean of 11 months. These had a higher prevalence of infection, perioperative factors and comorbidities. Late failures occurred at a mean of 119.2 months. Other major causes of failure included instability (28.9%), wear (24.5%) and component loosening suggesting the importance of modifications in technique, implants and other areas. Application of these findings will ultimately reduce revision numbers through continued refinement of total knee arthroplasty practice and through further specific investigation of these modes of failure. LEVEL OF EVIDENCE: Therapeutic study, level II-2 (prospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2006

Radiographic prediction of intraoperative bone loss in knee arthroplasty revision.

UNLABELLED: A key challenge for orthopaedic surgeons performing revision total knee arthroplasty is the management of bone loss. The goal of our study was to test the validity of predicting bone loss from preoperative radiographs using two commonly utilized bone loss assessments: the Anderson Orthopaedic Research Institute and University of Pennsylvania systems and secondarily to assess the frequency and severity of bone loss in a prospective study of total knee arthroplasty revisions. Ninety-eight total knee arthroplasty revision patients were assessed and bone loss was detected in 76 (77.6%) patients preoperatively and intraoperatively. The validity of both systems was established. Agreement between preoperative and intraoperative Anderson Orthopaedic Research Institute classification was fair for the femur and good for the tibia. All University of Pennsylvania preoperative measures were correlated with intraoperative measures. Establishing valid and reliable preoperative systems of measuring bone loss facilitates planning of total knee arthroplasty revision and rehabilitation and meaningful comparisons between different series of patients and treatment protocols. LEVEL OF EVIDENCE: Diagnostic study, level I (prospective testing of previously developed diagnostic criteria on consecutive patients [with universally applied reference "gold" standard]). See Author Guidelines for a complete description of levels of evidence.

Adult↗
PubMed2006

Extensor mechanism disruption after total knee arthroplasty.

UNLABELLED: Extensor mechanism disruption after total knee arthroplasty is a challenging complication for orthopaedic surgeons. The treatment options for repair include observation, direct primary repair, direct primary repair with synthetic ligament or autogenous tissue augmentation, or reconstruction with allograft tissue. A computerized systemic review and literature search was performed to identify the relevant literature on extensor mechanism disruptions associated with total knee arthroplasty. A comprehensive review of the literature and description of relevant treatment options and outcomes were performed using the information gained with the literature review. A multi-center prospective study on a consecutive series of patients recruited from the North American Knee Arthroplasty Revision (NAKAR) study was performed and data collected pre-operatively, intra-operatively, and post-operatively on patients that had a failed total knee arthroplasty using validated health related quality of life measures was analyzed. Six out of 290 patients in the study had extensor mechanism disruption and this group of patients had overall worse functional outcomes. The results of the study have solidified our knowledge that patients with extensor mechanism disruptions have worse functional outcomes and will need intensive management and rehabilitation. LEVEL OF EVIDENCE: Economic and decision analyses, level III (systematic review of level III studies). See Guide for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2006

Increased surgical volume is associated with lower THA dislocation rates.

The presumed correlation between an increasing volume of health care procedures and an improvement in outcomes is sometimes referred to as the practice-makes-perfect effect. Growing interest in outcomes-based research has led to numerous papers examining this relationship for various surgical procedures, including total hip arthroplasty. The results of these studies have important implications for consumers, providers, and healthcare financers. Accordingly, we review the literature to date examining surgeon and hospital volume effects on hip arthroplasty outcomes, with a specific focus on the effects of volume on dislocation. A systemic review of the literature demonstrates a substantial positive association between surgical volumes and improvement in most THA outcomes, including dislocation; that is, increasing surgical volume is associated with lower dislocation rates. This correlation appears to be stronger and is more clearly established for surgeon volumes than it is for hospital volumes.

Arthroplasty, Replacement, Hip↗
PubMed2006

Does surgical approach affect total hip arthroplasty dislocation rates?

Dislocation is a common complication of total hip arthroplasty, but exact effect of surgical approach on dislocation rates remains unclear. Because little randomized prospective data exist in this context, we performed a meta-analysis comparing dislocation rates using the posterior approach with and without soft tissue repair. A systematic literature review resulted in five studies which directly compared the posterior approach with and without soft tissue repair. The dislocation rates with and without repair were 0.49% and 4.46%, respectively. The relative risk for dislocation was determined using a fixed effects model with chi square test for interstudy heterogeneity. The posterior approach without soft tissue repair was found to have an 8.21 times greater relative risk of dislocation than with soft tissue repair (95% confidence interval, 4.05-16.67). A separate systematic review of 11 studies revealed comparable dislocation rates associated with the anterolateral, direct lateral, and posterior approaches with soft tissue repair (0.70%, 0.43%, and 1.01%, respectively). These data demonstrate that adequate soft tissue repair greatly reduces the relative risk of dislocation using the posterior approach, and that the dislocation rates for the three most prevalent approaches are similar. Further prospective randomized trials examining dislocation rates and other clinical parameters are needed.

Age Distribution↗
PubMed2005

Total knee arthroplasty in juvenile rheumatoid arthritis.

BACKGROUND: There is a paucity of reports regarding the long-term results of total knee arthroplasty in patients with juvenile rheumatoid arthritis. The purpose of this study was to evaluate the outcome of total knee arthroplasty in patients with juvenile rheumatoid arthritis who had been followed for a minimum of twelve years. METHODS: Eight consecutive patients (fifteen knees) with juvenile rheumatoid arthritis underwent total knee arthroplasty at an average age of 16.8 years. Clinical evaluation of pain status, range of motion, and the ability to walk and radiographic evaluation of the alignment of the knees and component loosening were performed preoperatively and at a mean of 15.5 years postoperatively. RESULTS: All patients had substantial pain and functional limitation before the surgery, and seven of the eight patients used a wheelchair. At the time of the latest follow-up, which was after revision surgery in three patients, all of the knees were pain-free and six patients were able to walk about the community. The mean arc of motion had increased from 36 degrees to 79 degrees . The final radiographic evaluation showed that thirteen of the fifteen knees were in neutral alignment and two were in valgus. Failure, defined as revision of any of the components or definite loosening as seen radiographically, occurred in three knees. CONCLUSIONS: Good results, in terms of pain relief and restoration of function, were seen at a minimum of twelve years following total knee arthroplasty in our series of patients with juvenile rheumatoid arthritis. This procedure is a reasonable option when nonoperative therapy has been inadequate for patients with severe disability and pain in this relatively young population.

Adolescent↗
PubMed2005

Development and validation of a lower-extremity activity scale. Use for patients treated with revision total knee arthroplasty.

BACKGROUND: Valid outcome measurement tools are required to reliably demonstrate the effectiveness and clinical outcomes of lower-extremity arthroplasty. Having ascertained a lack of a practical and valid measure of the change in actual daily physical activity that occurs prior to and following lower-limb arthroplasty, we developed and validated a lower-extremity activity scale. METHODS: The eighteen-level self-administered scale was developed with the aid of content experts to ensure face validity. Validity and reliability were assessed with the use of (1) pedometer measurements of seventy subjects over seven days; (2) next-of-kin proxy measurements of the activity levels of ninety patients before they underwent lower-limb arthroplasty; and (3) application, and correlation with the Western Ontario and McMaster Universities Osteoarthritis Index scores, in a prospective seventeen-center clinical study of 297 consecutive patients undergoing revision total knee arthroplasty. In this latter study, demographic and comorbidity data were also collected. Univariate and bivariate correlations were performed, and a multivariate structured equation modeling approach was used to further test responsiveness, reliability, and validity of the lower-extremity activity scale. RESULTS: Pedometer readings correlated with the activity levels derived with the lower-extremity activity scale (r = 0.79). Of note was the finding that age, weight, and body mass index did not correlate well with the average number of steps per day (r = -0.32, -0.32, and -0.25, respectively). A significant correlation was found between the lower-extremity activity scores recorded by the patients and those reported by their next of kin (Pearson correlation, r = 0.715; p = 0.0001) and between the initial lower-extremity activity scores and two-week-retest scores (intraclass correlation = 0.9147; p < 0.0001), demonstrating the validity and reliability of the scale. The lower-extremity activity scale was responsive, accurately reflecting changes in the patient's condition between baseline and the time of follow-up (p < 0.001), and it was reliable, with baseline values correlating with follow-up scores (p < 0.001). The convergent validity of the lower-extremity activity scale was established by correlations with the function scores (r = -0.301, p < 0.001) and pain scores (r = -0.241, p < 0.001) derived with the Western Ontario and McMaster Universities Osteoarthritis Index and with a higher number of comorbidities (r = -0.244, p < 0.001). Multivariate path modeling further demonstrated diminished activity in patients who had more difficulty in functioning and a greater number of comorbidities. CONCLUSIONS: We developed a lower-extremity activity scale and validated that it was an effective instrument for the assessment of patients' actual activity levels. It is easy to apply and interpret, and it is valid and ready for use in the clinical setting. This scale will allow more accurate analysis and prediction of outcomes. Consequently, it will become a useful, practical adjunct to objective clinical decision-making and intervention for patients undergoing arthroplasty.

Activities of Daily Living↗
PubMed2004

Routine recovery room radiographs after total hip arthroplasty: ineffective for screening and unsuitable as baseline for longitudinal follow-up evaluation.

To assess the usefulness of traditional recovery room check radiographs after total hip arthroplasty, we retrospectively analysed 2,065 consecutive hip arthroplasty patients. We found a 0.1% rate of radiologic diagnosis of dislocation in the population screened. In 100 patients randomly selected for comparison, the image quality in the recovery room radiographs was significantly inferior to standardized departmental radiographs (P<.001), with further significant differences between cup version (P<.001), and stem alignment assessments (P=.002). We found good agreement between the authors in the assessments of these radiographs with a weighted kappa statistic of 0.8653 (P<.0001). Seven recovery room radiographs needed repetition for poor quality versus none of the departmental films (P=.007). With such poor information and diagnostic yield for follow-up and screening, these investigations should only be performed when clinically indicated.

Arthroplasty, Replacement, Hip↗
PubMed2004

Postoperative stiffness and adhesion formation around repaired and immobilized Achilles tenotomies are prevented using a model of heat shock protein induction.

BACKGROUND: Tendon repair and subsequent immobilization is frequently complicated by postoperative stiffness secondary to inflammation and peritendinous adhesions. Thermal preconditioning is known to reduce inflammation by inducing formation of cytoprotective heat shock proteins. This study evaluates the role of thermal preconditioning following complete division and repair of the Achilles tendon, with subsequent immobilization, mimicking the typical clinical scenario. MATERIALS AND METHODS: Twenty-four New Zealand White rabbits were used in the study. The treatment group underwent thermal preconditioning, by elevating their core temperature to 41.5 degrees C for 20 minutes. The Achilles tendon of the hindlimb was divided and repaired 18 hours following thermal preconditioning. The animals were sacrificed following 3 weeks of immobilization. Range of movement of the ankle, tendon gliding, quantity of adhesions, and weight of repaired tendons were assessed. RESULTS: Loss of range of movement at the ankle was significantly less in the treatment group versus controls (P = 0.02). The quantity of adhesions and weight of the repaired tendons were significantly reduced in the treatment group (P = <0.001 and P = 0.005, respectively). Tendon gliding relative to the surrounding soft tissue was also significantly improved in the treatment group (P = 0.002). CONCLUSION: Preconditioned animals demonstrated a significantly better range of ankle movement, decreases in adhesion formation and in the gliding, and dimensions of tendons. Thermal preconditioning therefore has the potential to improve clinical results in tendon surgery following repair and immobilization.

Achilles Tendon↗
PubMed2003

Triple pelvic osteotomy in Legg-Calvé-Perthes disease using a single anterolateral incision.

Pelvic osteotomy has a small role to play in the management of Legg-Calvé-Perthes disease. Residual acetabular dysplasia or incongruity can be corrected by rotational acetabuloplasty. In skeletally immature patients this can be performed by complete or incomplete innominate osteotomies. We present the case of a 12-year-old child with residual acetabular dysplasia, resulting from Legg-Calvé-Perthes disease, which was treated by a triple pelvic osteotomy performed by a small single anterolateral incision.

Child↗
PubMed2003

Comparison of different anti-inflammatory agents in suppressing the monocyte response to orthopedic particles.

Three different anti-inflammatory agents--diclofenac, dexamethasone, and N-acetylcysteine--were compared to evaluate their effectiveness in suppressing monocyte-macrophage cell culture activation and mediator release (tumor necrosis factor-alpha [TNF-alpha] and interleukin-1beta [IL-1beta]) in response to polymethylmethacrylate particulate debris. N-acetylcysteine and diclofenac were most effective in suppressing TNF-alpha and IL-1beta expression by the monocyte-macrophages. Dexamethasone reduced TNF-alpha expression but was not as effective suppressing IL-1beta expression. N-acetylcysteine and dexamethasone had no effect on cell viability whereas diclofenac at the highest concentrations decreased cell viabilities. N-acetylcysteine and diclofenac, but less so dexamethasone, are effective in suppressing wear debris-related cell activation and mediator release and thus potentially represent therapeutic or preventive modalities for periprosthetic osteolysis.

Acetylcysteine↗
PubMed2002

Simultaneous hip and upper limb fracture in the elderly: incidence, features and management considerations.

We performed a retrospective analysis of all patients admitted to a single unit over 4 years with fractured neck of femur. Of the 760 patients admitted over this period of time 36 (4.7%) were found to also have a fracture of the upper limb. The associated upper limb fractures were distal radius (n=28), olecranon (n=2) and neck of humerus (n=5) and fifth metacarpal (n=1), with the same ratio of intracapsular to extracapsular fractures as the whole group. The female to male ratio in the isolated hip fracture group was 2.4:1 and for the combined fractures group was 8:1 (difference P=0.014). The mean patient age was 77.3 years for isolated hip fractures and 83.9 for the combined group (P=0.037). The mean total length of stay in hospital for isolated hip fracture was 15.6 days and for combined fractures was 20.4 days (P=0.010). We have demonstrated that combined upper limb and neck of femur fractures occur in a population that is older and predominantly female. They are associated with a significant increase in hospital stay and increased difficulties in mobilisation as a consequence of the combined fractures. It is therefore important to recognise this specific subgroup of patients presenting with hip fractures in order to ensure that they receive adequate treatment and rehabilitation and that the use of valuable health care resources are optimised.

Accidental Falls↗
PubMed2002

Inhibition of polymethylmethacrylate particle-induced monocyte activation and IL-1beta and TNF-alpha expression by the antioxidant agent N-acetylcysteine.

We investigated the effectiveness of an antioxidant agent, N-acetylcysteine (NAC), in suppressing macrophage activation and mediator release in response to particulate debris. Polymethylmethacrylate (PMMA) particle-stimulated monocyte-macrophages were cultured alone and with varying concentrations of NAC. Tumor necrosis factor alpha (TNFalpha) and interleukin-1beta (IL-1beta) expression in the resultant cultures were measured using enzyme-linked immunosorbant assays. The ultrastructural effect of treatment was also assessed by electron microscopy. Cell viability in the various cultures was measured to rule out an effect of cytotoxicity. NAC treatment reduced TNFalpha and IL-1beta expression by the monocyte-macrophages. Culturing with NAC was also associated with less ultrastructural activation of the monocytes. Furthermore, NAC was not associated with any adverse effect on cell viability in the concentrations used. Our findings demonstrate the effectiveness of the antioxidant N-acetylcysteine in suppressing the cell activation and TNFalpha release seen on exposure to wear debris. This represents a novel potential therapeutic method in the prevention or treatment of periprosthetic osteolysis.

Acetylcysteine↗
PubMed2002

Thermal preconditioning prevents peritendinous adhesions and inflammation.

Adhesion formation is one of the foremost obstacles to a reliably good outcome in tendon and joint surgery. Thermal preconditioning has been found to reduce the inflammatory response through the induction of molecular chaperone expression, a recently described family of cytoprotective intracellular proteins. The authors analyzed the effect of thermal preconditioning on the inflammatory response to surgery, on tendon healing, and on the formation of peritendinous adhesions in 16 New Zealand White rabbits. Very significant decreases in adhesion formation and in the gliding and dimensions of tendons in animals that had thermal preconditioning were found. Tendons from these animals also showed a decreased level of adhesion formation and a significantly diminished inflammatory response on histologic examination with no biomechanically significant deleterious effect on the strength of tendon healing on testing load to failure. These findings are consistent with induction of heat shock proteins by hyperthermic pretreatment. Such prevention of peritendinous adhesions and the inflammatory response to injury and surgery without compromising healing are findings that have significant implications for tendon surgery and all surgery involving joints and soft tissues.

Animals↗