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Biomedical subjects

D S Hungerford

Publications and source records attributed to D S Hungerford.

At least 37 records · Page 2Linked to original sources
PubMed2000

Evaluation of preoperative cultures before second-stage reimplantation of a total knee prosthesis complicated by infection. A comparison-group study.

BACKGROUND: Two-stage reimplantation has proven to be highly successful in the treatment of patients with infection at the site of a total knee arthroplasty. However, up to 20 percent of patients have a recurrence of infection following this treatment. The purpose of our study was to determine whether aspiration of the affected joint and culture of the specimen, performed before reimplantation and after discontinuation of antibiotic therapy, would help to identify patients who might have a recurrent infection. METHODS: We prospectively followed sixty-nine patients who were treated for a culture-proven deep infection at the site of a total knee arthroplasty. Group I consisted of thirty-five patients who were treated with removal of the prosthetic components and irrigation and debridement of the joint, followed by six weeks of antibiotic therapy and reimplantation of a prosthesis. Group II was composed of thirty-four patients who were treated with removal of the components and irrigation and debridement of the joint, six weeks of antibiotic therapy, and then repeat culture four weeks after the antibiotic course had ended. If the culture was negative, the patient was managed with a second-stage reimplantation of a prosthesis. If the culture was positive, the protocol was repeated, beginning with irrigation and debridement. The two groups were similar with regard to male-to-female ratio, age, preoperative Knee Society scores, time since primary surgery, types of infectious organisms, duration of symptoms, duration of follow-up, and number of previous revisions. All of the patients were evaluated clinically with use of the objective scoring system of the Knee Society and were followed with serial radiographs. Success was defined as no infection and a functional prosthesis, with a Knee Society score of at least 75 points at the last (thirty-six-month-minimum) follow-up evaluation. RESULTS: Of the thirty-five patients in Group I, five (14 percent) had recurrence of infection. One of the patients was managed with a successful second-stage revision, three were managed with arthrodesis of the knee, and one continued with chronic antibiotic suppressive treatment. Of the thirty-four patients in Group II, three (9 percent) had a positive culture after the course of antibiotics. The protocol was repeated for all three, and they subsequently had a successful second revision. One other patient (3 percent) in Group II, who had a negative culture, had a recurrent infection and was eventually managed with arthrodesis of the knee. CONCLUSIONS: Prerevision cultures, grown after discontinuation of antibiotic treatment and before reimplantation of the components, helped to identify the patients with infection at the site of a total knee arthroplasty in whom the infection might recur. The performance of aspiration and cultures resulted in a substantial improvement in the clinical outcome.

Aged↗
PubMed2000

Atraumatic osteonecrosis of the humeral head.

OBJECTIVE: To define the epidemiology, clinical and radiographic presentation, treatment, and prognosis of atraumatic osteonecrosis of the humeral head. METHODS: Of the 1,056 patients managed for osteonecrosis of any joint between July 1, 1974, and December 1, 1996, 127 shoulders in 73 patients were treated for atraumatic osteonecrosis of the proximal humerus. Clinical and radiographic characterization of this patient cohort was performed. RESULTS: At presentation, there were 47 women and 26 men with a mean age of 41 years (range 20-60). Numerous associated factors were noted: alcohol use (38%), moderate smoking (30%), asthma (8%), and nephrosis (3%). A corticosteroid association was noted in 60 patients (82%) and 42 of the patients (58%) had an immunocompromising disease. The severity of humeral head osteonecrosis did not correlate with dose or duration of corticosteroid therapy. According to the modified Ficat and Arlet radiographic staging system, there were 20 shoulders with Stage I disease, 55 shoulders with stage II disease, and 52 shoulders with Stage ITI or IV disease. Seventy-four of the shoulders treated with core decompression (78%) had good to excellent clinical outcomes at a mean followup of 6 years (range 2-21). Fourteen of the 16 patients (88%) treated with hemiarthroplasty or total shoulder arthroplasty were clinically successful at a mean followup 4 years (range 2-11). CONCLUSION: We observed a low incidence of humeral head involvement in the osteonecrosis patient cohort (7% of all osteonecrosis patients), and a high incidence of corticosteroid use (82%). hip involvement (81%), and bilateral disease (74%). Osteonecrosis of the humeral head should be suspected in patients presenting with shoulder pain and a history of osteonecrosis in other joints. Hip screening for osteonecrosis is advocated in patients with shoulder involvement. Early detection of shoulder osteonecrosis may permit a more conservative, joint-sparing approach as an alternative to surgical management.

Adult↗
PubMed2000

Reinfusion drains after primary total hip and total knee arthroplasty.

The purposes of this study were to evaluate the efficacy of intraoperative surgeon-elected reinfusion drain placement and to determine whether drainage at 90 minutes is useful in predicting the need for a reinfusion drain. In the standard drain hip arthroplasty group, 6 of 30 patients (20%) received a reinfusion, similar to the 11 of 41 patients (27%) in the reinfusion drain group. In the total knee arthroplasty group, 38 of 45 patients (84%) in the standard group had reinfusion, similar to the 23 of 27 patients (85%) in the reinfusion drain group. The surgeon could not predict intraoperatively which patients would need a subsequent reinfusion drain. However, in more than 94% of the cases, one could know by 90 minutes postoperatively whether a reinfusion would be necessary. We believe that a drain that can be converted to a reinfusion drain in the recovery room would be the most cost-effective drain system.

Adult↗
PubMed1999

Immunohistochemical evaluation of interface membranes from failed cemented and uncemented acetabular components.

Aseptic loosening of acetabular components is a primary factor compromising the long-term outcome of cemented and cementless total hip replacement. It is unknown whether the pathogenesis of the loosening process is identical for both types of fixation. The specific aim of this study was to determine whether there is a difference in the cellular and cytokine profiles of interface membranes removed from between the implant and the host bone from failed cemented (n = 5) and failed cementless acetabulae (n = 5). Routine histology and immunohistochemical evaluations were completed on each tissue specimen. The monoclonal antibodies used included those specific for cell types (macrophages, fibroblasts, T lymphocytes) and for cytokines (IL-1beta, IL-6, TNF-alpha). The patients were all revised for loosening. The time to revision was significantly longer for the cemented group (16.6 yr; 13-21 range) than for the cementless group (8.9 yr; 4-13 range). In all cases, slides from each group stained positively for each of the cell types and cytokines evaluated. Immunohistochemical analyses indicated a predominance of macrophages and ubiquitous staining for the cytokines IL-1beta and TNF-alpha within the membranes of both patient groups. The intensities of cytokine staining were similar for both patient groups. More regions of fibroblastic connective tissue were observed surrounding failed cementless components as compared to those of the cemented group. The clinical ramification of our findings is that, despite differences in the cellular composition of the periprosthetic membranes, the membranes from failed cemented and cementless implants contain cytokines, which have been shown to be capable of modulating the inflammatory response. These inflammatory mediators are likely to play a significant role in the development of osteolysis and prosthetic loosening.

Acetabulum↗
PubMed1999

Effect of prosthetic titanium wear debris on mitogen-induced monocyte and lymphoid activation.

Wear debris generated by joint implant components has been reported to activate inflammatory and immune cells. Particulate debris derived from prosthetic material induces monocytes/macrophages, lymphocytes, synoviocytes, and fibroblasts to secrete cellular products, such as cytokines, which mediate inflammation. It has been speculated that degradation products impair the ability of inflammatory and immune cells to mount a protective response against noxious agents and infectious organisms by interfering with cell activation. Recent in vitro studies suggest that soluble metal ions inhibit T and B cell activation, but it is not known whether insoluble metal particles generated by prosthetic wear in tissue have the same effect. The purpose of the present study was to determine whether titanium wear debris retrieved from periprosthetic tissues surrounding a failed knee prosthesis suppresses activation of human monocytic and lymphoid cells. Peripheral blood monocytes and lymphocytes were incubated with the nonspecific activator pokeweed mitogen (PWM) in the presence or absence of titanium particles. Cell proliferative capacity and production of interleukins IL-1beta and IL-2 were determined as measures of activation. Titanium wear debris induced monocyte secretion of IL-1beta at levels comparable to those induced by PWM alone. In combination with PWM, titanium wear debris stimulated monocytes to secrete higher concentrations of IL-1beta than is stimulated by titanium itself or by PWM alone. Titanium wear debris did not activate lymphocytes, as indicated by marginal changes in DNA synthesis and IL-2 secretion, nor did it suppress the PWM-induced stimulation of DNA synthesis and IL-2 secretion. Our study suggests that nonspecific mitogen activators in spite of exposure to titanium wear debris can stimulate monocytic and lymphoid cells.

Biocompatible Materials↗
PubMed1999

Variation of rotation moment arms with hip flexion.

Excessive flexion and internal rotation of the hip is a common gait abnormality among individuals with cerebral palsy. The purpose of this study was to examine the influence of hip flexion on the rotational moment arms of the hip muscles. We hypothesized that flexion of the hip would increase internal rotation moment arms and decrease external rotation moment arms of the primary hip rotators. To test this hypothesis we measured rotational moment arms of the gluteus maximus (six compartments), gluteus medius (four compartments), gluteus minimus (three compartments) iliopsoas, piriformis, quadratus femoris, obturator internus, and obturator externus. Moment arms were measured at hip flexion angles of 0, 20, 45, 60, and 90 degrees in four cadavers. A three-dimensional computer model of the hip muscles was developed and compared to the experimental measurements. The experimental results and the computer model showed that the internal rotation moment arms of some muscles increase with flexion; the external rotation moment arms of other muscles decrease, and some muscles switch from external rotation to internal rotation as the hip is flexed. This trend toward internal rotation with hip flexion was apparent in 15 of the 18 muscle compartments we examined, suggesting that excessive hip flexion may exacerbate internal rotation of the hip. The gluteus maximus was found to have a large capacity for external rotation. Enhancing the activation of the gluteus maximus, a muscle that is frequently underactive in persons with cerebral palsy, may help correct excessive flexion and internal rotation of the hip.

Biomechanical Phenomena↗
PubMed1999

Clinical experience with a proximally porous-coated second-generation cementless total hip prosthesis: minimum 5-year follow-up.

This study reports the minimum 5-year follow-up of our experience with the Porous-Coated Anatomic E (PCA-E) series femoral stem and the modular acetabular cup. A total of 115 consecutive total hip replacements using PCA-E series (Howmedica, Rutherford, NJ) were performed in 108 patients. Six patients whose hips were performing well clinically died before 5-year follow-up and were excluded from the final evaluation. The remaining 109 hips (102 patients) were assessed at a mean follow-up of 72 months (range, 60-84 months). The hip diagnoses were osteoarthritis in 73, osteonecrosis in 31, rheumatoid arthritis in 2, and hip dysplasia in 3. The mean age was 56 years (range, 24-83 years). Three hips were revised: 1 because of late hematogenous infection, 1 because of aseptic loosening of the femoral component, and 1 because of postoperative loosening of an acetabular component. The Harris hip scores improved from a mean of 50 points (range, 20-66 points) preoperatively to a mean of 92 points (range, 64-100 points) at final follow-up. The score differed in each Charnley functional class, with a mean of 93 points (range, 72-100 points) in 57 hips of class A (no other joint involvement); 90 points (range, 58-100 points) in 26 hips of class B (opposite hip involvement); and 85 points (range, 37-100 points) in 26 hips of class C (multiple joint involvement or severe systemic disease). Out of 106 hips that had a full radiographic evaluation performed, 103 femoral components revealed stable bony ingrowth, 2 revealed stable fibrous ingrowth, and 1 showed migration with progressive loosening. This patient with radiographic loosening has minimal symptoms and has not required or been offered further surgery (Harris hip score of 86 points). The low aseptic loosening rate (2%) at minimum 5-year follow-up compares favorably with any cemented or cementless series. The osteolysis that was seen was focal and localized. The short follow-up does not allow determination of progression. There were no cases of distal osteolysis. We attribute the improved results from reported first-generation experience to multiple factors, including increased number of sizes (9 vs 6), increased proportional metaphyseal size, improved polyethylene manufacture (ram extruded vs machined), improved acetabular locking mechanism, and change to 26-mm from 32-mm femoral heads.

Adult↗
PubMed1999

Eliminating patellofemoral complications in total knee arthroplasty: clinical and radiographic results of 121 consecutive cases using the Duracon system.

This study reports the minimum 5-year follow-up of our experience with the Duracon Total Knee Arthroplasty System. A total of 121 consecutive total knee replacements using the Duracon system (Howmedica, Rutherford, NJ) were performed in 104 patients. Three patients died before the 5-year follow-up and were excluded from the final evaluation. The remaining 118 knees (101 patients) were assessed at a mean follow-up of 65 months (range, 60-80 months). The knee diagnoses were osteoarthritis in 97 patients, rheumatoid arthritis in 2 patients, osteonecrosis in 1 patient, and pigmented villonodular synovitis in 1 patient. The mean age was 70 years (range, 28-85 years). There were no reoperations for aseptic loosening, and there have been no reoperations for patellofemoral problems. At final follow-up evaluation, 112 knees (96%) had good or excellent results, and 6 knees (4%) had poor clinical results or went on to revision. For the surviving knees, the preoperative Knee Society objective score improved from a mean of 52 points (range, 20-72 points) to a final follow-up mean of 94 points (range, 66-100 points). Five knees needed reoperations: 2 knees in 1 patient because of acute hematogenous infection at 12 months, 1 knee because of a supracondylar femur fracture, 1 because of a patellar tendon rupture, and 1 to increase polyethylene thickness because of instability. The lack of aseptic loosening at the minimum 5-year follow-up compares favorably with any cemented or cementless series of knee replacement. The almost complete absence of patellofemoral complications in this series also indicates that the design changes, with particular attention to the trochlea design and patellofemoral contact throughout full flexion, have achieved their intended purpose. The results are encouraging at midterm, awaiting true long-term (15-20 years) follow-up.

Aged↗
PubMed1999

Operative management and outcome of complex wounds following total knee arthroplasty.

This study describes the treatment protocol for and the outcome of the management of complex wounds around total knee replacements. An analysis of 28 patients (29 knees) with complex defects who had surgery between January 1, 1986, and July 30, 1996, was performed. A specific management protocol was applied to each knee on the basis of the size and depth of the wound, the presence of infection, and the quality of soft tissue. Primary treatment included local wound care, debridement, and skin grafting or coverage with a fasciocutaneous flap, pedicled muscle flap, or free muscle transfer. Postoperatively, knees were evaluated using the Knee Society objective score. Successful salvage of the lower extremity was obtained in 28 knees (97 percent) and of the knee prosthesis in 24 of 29 knees (83 percent). Secondary plastic surgery procedures were necessary in five knees (17 percent), and secondary orthopedic procedures were necessary in four knees (14 percent). Successful salvage of total knee arthroplasty in the presence of a complex wound requires early identification of infection, aggressive irrigation and debridement, and early appropriate soft-tissue coverage. The use of our proposed algorithm will facilitate management of these complex wounds.

Adult↗
PubMed1999

Infections associated with dental procedures in total hip arthroplasty.

Dental procedures may lead to a transient bacteraemia lasting for up to 30 minutes. Of the numerous cases of total hip arthroplasty (THA) reported which have been infected from haematogenous sources, dental procedures have been involved only infrequently. We reviewed the records of 2973 patients after THA. Of the late infections identified in 52 patients, three (6%) were strongly associated with a dental procedure. Infection was diagnosed by culture from the affected joint; Streptococcus viridans was identified in two cases and Peptostreptococcus in one. One patient had diabetes mellitus and another rheumatoid arthritis, both conditions predisposing to infection. The dental operations all lasted for more than 45 minutes and no patient received perioperative antibiotics. Infection of a THA after dental procedures is more common than has been previously suspected. Patients with systemic disease, or who are undergoing extensive procedures, should be considered for prophylactic antibiotic treatment.

Antibiotic Prophylaxis↗
PubMed1999

Proximally porous-coated ingrowth prostheses: limits of use.

Callaghan has suggested that the most important factor in obtaining optimal results after total hip arthroplasty may be the ability to determine when to use cemented or cementless fixation. This article has presented the indications and relative contraindications for use of proximally porous-coated prostheses. Midterm results suggest that with appropriate patient selection, excellent clinical results can be achieved with currently available proximally porous-coated prostheses. Use of proximally coated prostheses is indicated for primary total hip arthroplasty in patients aged >70 years with good bone stock. Relative contraindications are based on interference with bone ingrowth or with the ability to achieve a congruent fit, both of which preclude establishment of rigid initial stability. These conditions include metabolic bone disease such as osteoporosis, osteomalacia, Gaucher's disease, sickle cell disorders, and Paget's disease; significant anatomical distortion, as seen in developmental dysplasia of the hip with anteversion, prior osteotomy, or intertrochanteric fracture; Dorr type C bone; and current treatment with radiation, chemotherapy, indomethacin, or diphosphonates. The same relative contraindications to use are applicable in revision situations. Further, proximally porous-coated prostheses should not be used for revision arthroplasty in the setting of massive bone loss, limited life expectancy, or inability to participate in protected weight bearing. These devices may be used successfully in revision arthroplasty when the hip has minimal or moderate bone loss, and occasionally in the setting of severe bone loss. As further information is revealed through the long-term (10-20 years) results of proximally coated prostheses, further refinements and knowledge of the indications and contraindications for the use of these prostheses will be revealed.

Arthroplasty, Replacement, Hip↗
PubMed1999

Patellofemoral complications after total knee arthroplasty: a comparison of Modular Porous-Coated Anatomic with Duracon prostheses.

Clinical and radiographic analyses were used to compare results obtained in 45 patients who underwent a Modular Porous-Coated Anatomic total knee arthroplasty with results in a similar group of 45 patients who underwent a Duracon total knee arthroplasty. The surgeries were consecutively performed over an 8-month period, and follow-up evaluation averaged 63 months. The two patient groups were similar with regard to the following variables: age, sex, diagnosis, height, weight, and preoperative and postoperative activity levels. Whereas both Duracon and Modular total knee arthroplasty prostheses yielded similar results approximately 5 years after surgery, the data suggest that Duracon appears to minimize patellofemoral complications.

Adult↗