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Biomedical subjects

P F Sharkey

Publications and source records attributed to P F Sharkey.

At least 19 recordsLinked to original sources
PubMed2001

Cementless femoral fixation in the rheumatoid patient undergoing total hip arthroplasty: minimum 5-year results.

Sixty-two total hip arthroplasties in 49 patients with a diagnosis of rheumatoid arthritis were performed between November 1986 and December 1992. All components were titanium alloy with a circumferential plasma-spray porous coating. Four patients (4 hips) died before 5-year follow-up, and 6 patients (8 hips) were lost to follow-up, leaving 39 patients (50 hips) for review at a minimum 5-year follow-up after surgery (mean, 8 years; range, 5-12 years). There were 12 men and 27 women, with a mean age at time of surgery of 55 years (range, 25-77 years) and a mean weight of 69 kg (range, 42-109 kg). Compared with the preoperative Charnley scores, there was significant improvement in the postoperative scores: pain, from 2.7 to 5.7, and function, from 3.2 to 5.3. Thigh pain was present in 1 patient (1 hip) (2.0%). No femoral fractures occurred intraoperatively with the insertion of the prosthesis. Spot welds consistent with bone ingrowth were identified in all of the femoral components. No femoral components showed evidence of radiographic loosening or required revision for aseptic loosening or incapacitating thigh pain, but 7 acetabular revisions were performed. Uncemented femoral fixation with this component design in rheumatoid patients appears to be a promising treatment.

Adult↗
PubMed2001

Fixed minidose versus-adjusted low-dose warfarin after total joint arthroplasty: a randomized prospective study.

Widespread use of adjusted low-dose warfarin has been limited by the inconvenience of outpatient laboratory monitoring and the perceived risk of bleeding complications. We sought to determine if the dose of warfarin could be lowered safely even further, eliminating the need for laboratory monitoring and lowering the complication rate. Two hundred forty-five Patients undergoing primary total joint arthroplasty (n = 245) were randomized prospectively to adjusted low-dose warfarin (international normalized ratio [INR], 1.4-1.8) or fixed minidose warfarin (2 mg daily, regardless of INR) before hospital discharge. Prophylaxis continued for 6 weeks, with twice-weekly laboratory monitoring. Patients were followed for bleeding, thromboembolic events, and minor reported complications of warfarin therapy. With the numbers available, the rates of thromboembolic and bleeding events were not significantly different using equivalence analysis. Of patients in the fixed group, 8% had INRs >3.1, necessitating a decrease in dosage to 1 mg. Although such a fixed-dose protocol may simplify outpatient prophylaxis, intermittent monitoring still would be required because a subset of patients achieve a moderate level of anticoagulation and would be at risk for bleeding complications.

Adult↗
PubMed2001

Effect of femoral component offset on polyethylene wear in total hip arthroplasty.

Seventeen staged, bilateral total hip arthroplasties performed in 17 patients were reviewed to compare side-to-side polyethylene wear. Implants used on both sides were similar except for implant offset: one hip in each patient was replaced using a femoral component having a standard implant offset, whereas the other side had a lateral offset implant. The mean followup was 5.70 years (range, 2-10.2 years) on the side with a standard femoral implant and 5.67 years (range, 2-9.7 years) on the side with a lateralized femoral component. The only statistically different parameter between the sides was the femoral component offset. All other parameters affecting polyethylene wear, such as period of followup, head size, head type, cup size, cup inclination, medialization of cup, and patient-related factors were similar on both sides. On the side with a standard femoral component, the mean actual prosthetic offset (determined by manufacturer's specifications) was 35.2 mm and the radiologic offset was 31.5 mm. On the side with a lateralized femoral component, the actual prosthetic offset was 42.5 mm and the radiologic offset was 40.1 mm. The difference in offsets between the sides was statistically significant. The mean preoperative offset of the femur was 38.8 mm. Regression analysis revealed that only femoral component offset and cup size correlated significantly with linear wear rate. On the side with a standard femoral component, the linear wear rate was 0.21 mm per year, whereas on the side with a lateralized femoral component, the linear wear rate was 0.10 mm per year. The differences in the linear wear rates were significant. Lateralization of the femoral component in this series more closely restored preoperative hip biomechanics and significantly decreased polyethylene wear.

Adult↗
PubMed2001

Total hip arthroplasty using two different cementless tapered stems.

The authors report their 15-year experience with primary total hip arthroplasty using collarless, tapered, porous-coated femoral stems (Trilock and Taperloc) in patients with osteoarthritis, rheumatoid arthritis, and in octogenarians. Excellent clinical results were achieved in all groups at latest followup. For the patients with Trilock stems, Taperloc stems, and patients who were octogenarians and patients with rheumatoid arthritis, Charnley pain scores were 5.6, 5.5, 5.7, and 5.7; Charnley function scores were 5.2, 5.1, 4.2, and 5.3; Harris hip scores were 92, 92, 82, and 93 points, respectively. There was a 2% rate of thigh pain with the Trilock, 4% with Taperloc, 4% in octogenarians, and 2% in patients with rheumatoid arthritis. In 96% of the patients in the Trilock group, in 100% of the patients in the Taperloc group, in 100% of the patients who were octogenarians, and in 100% of the patients with rheumatoid arthritis, femoral components showed radiographic evidence of bone ingrowth. There were six (12%) femoral component revisions in the Trilock group (all secondary to nonmodularity of the component at the time of acetabular revision), one femoral component revision in the Taperloc group and no femoral component revisions in the patients who were octogenarians or who had rheumatoid arthritis. Design features (collarless tapered wedge fit, circumferentially porous-coated) virtually ensure bone ingrowth and are thought to be responsible for the excellent clinical results and longevity.

Adult↗
PubMed2001

Soft tissue injuries with the use of safe corridors for transfixion wire placement during external fixation of distal tibia fractures: an anatomic study.

OBJECTIVES: To determine which soft tissue structures are at risk and when joint violation can occur during small wire placement for hybrid external fixation of distal tibial fractures while adhering to published guidelines. DESIGN: Cadaver anatomic experiment. SETTING: University orthopaedic program. SUJBECTS: Five embalmed cadavers. INTERVENTION: Placement of small wire transfixion pins in the distal tibia. MAIN OUTCOME MEASUREMENTS: Dissection and measurements. METHODS: Four orthopaedic surgeons were shown diagrams that have been widely accepted as allowing for placement of transfixion pins in the distal tibia through safe corridors. Each of the orthopaedic surgeons was then asked to place two transfixion pins into each of five cadaver legs in a position that would provide stable external fixation of the metaphysis to the diaphysis with a circular fixator (forty pins total) for a distal tibial fracture within five centimeters of the plafond. The specimens were dissected, and pins impaling neurovascular structures, tendons, or the ankle capsule were recorded. The superior capsular synovial reflections were measured from the anterior joint line and the tip of the medial malleolus. These measurements were also performed on arthrograms of two extremities before their dissection. RESULTS: Fifty-five percent of the pins placed impaled at least one tendon that crosses the ankle joint. Neurovascular structures that were impaled included the saphenous vein (+/-10.5 percent) and the superficial peroneal nerve (+/-7.5 percent). One pin violated the superior capsular synovial reflection, which was an average of thirty-two millimeters (+/-1.58 millimeters) from the tip of the medial malleolus and twenty-one millimeters (+/-1.63 millimeters) from the anteromedial joint line. CONCLUSIONS: This study shows that tendons and neurovascular structures above the ankle are at risk during small transfixion pin placement, even when using safe corridors. Pins placed within two centimeters of the anterior joint line or three centimeters from the medial malleolus may be intracapsular.

Bone Nails↗
PubMed2001

Primary cementless total hip arthroplasty in octogenarians. Two to eleven-year follow-up.

BACKGROUND: Cementless total hip arthroplasty is an accepted alternative to total hip arthroplasty with cement in younger patients, but it remains controversial for elderly patients. The purpose of this study was to evaluate the clinical and radiographic outcomes of cementless total hip arthroplasty with use of a proximally coated stem in patients who were at least eighty years of age at the time of the operation. METHODS: One hundred and twenty-three cementless total hip replacements were performed for the treatment of osteoarthritis in 114 patients between the ages of eighty and eighty-nine years. Seven patients (eight hips) died within two years after the surgery, seventeen patients (eighteen hips) died more than two years postoperatively but were not followed for at least two years, and five hips were lost to follow-up; this left ninety-two hips in eighty-six patients for review. The mean duration of follow-up was five years (range, two to eleven years). For the clinical evaluation, the Charnley modification of the Merle d'Aubigné and Postel scale was used. In addition, preoperative and postoperative Harris hip scores were available for sixty-nine hips. Seventy-eight hips were followed radiographically for two years or more. The focus of the radiographic evaluation was the status of the fixation of the femoral and acetabular components as well as cup wear. RESULTS: Perioperative medical complications occurred in association with 24% (thirty) of the 123 operations, but there were no deaths. The mean Charnley scores for pain and function for the ninety-two hips that were followed clinically for at least two years improved by 3.0 and 1.4 points, respectively. The sixty-nine hips for which preoperative and postoperative Harris hip scores were available had a mean improvement of 42 points, with a mean score of 82 points at the last follow-up evaluation. Mild thigh pain was present in four patients, but it did not limit their activity. There were no femoral component revisions. All of the femoral components were radiographically stable and had bone ingrowth. No acetabular component failed by loosening, but 41% (thirty) of the seventy-three hips with radiographs available for measurement of wear showed polyethylene wear. Of the seventy-eight cups that were followed radiographically for two years or more, 4% (three) were associated with lysis, but none had been revised. CONCLUSIONS: Cementless fixation in the elderly is safe, effective, and durable at the time of two to eleven-year follow-up.

Aged↗
PubMed2000

Routine follow-up office visits after total joint replacement: do asymptomatic patients wish to comply?

A total of 100 patients presenting for routine office follow-up after total hip or knee arthroplasty completed questionnaires evaluating whether they preferred to come to the office for routine follow-up evaluation or whether they would have preferred an evaluation without an office visit. Of 100 patients, 45 would have preferred not to come into the office for a routine evaluation. They were content to mail completed questionnaires and radiographs to their physicians. The other 55 patients preferred office visits. These 2 groups were comparable for age, sex, height, weight, and number of surgeries (P > .11) Preoperative and postoperative scores were similar between the 2 groups (P > .39). None of the patients that would have preferred not to come in to the office believed that quality of care would be compromised. A significant number (45%) of patients would prefer not to come to the office because of the wages saved and time spared. Routine office visits may be eliminated for these patients through the use of health outcome devices, such as the SF-36, along with routine radiographs. The potential to decrease healthcare costs and increase patient satisfaction warrants the identification of these patients. Assessment of the effect on quality of care with elimination of routine follow-up visits requires further study.

Aged↗
PubMed2000

The bearing surface in total hip arthroplasty: evolution or revolution.

Highly cross-linked polyethylenes represent a new class of polyethylenes that demonstrate dramatic improvements of wear characteristics in laboratory tests. Cross-linked polyethylenes can be manufactured by a number of methods, all of which lead to some changes in the physical properties of the polyethylene. The very limited clinical information about cross-linked polyethylenes available has been favorable. Cross-linked polyethylenes appear to hold promise as an alternative to conventional polyethylene and to hard-on-hard bearing surfaces, but much more clinical information will be required before they can be recommended for routine clinical use.

Biomechanical Phenomena↗
PubMed1999

Factors influencing choice of implants in total hip arthroplasty and total knee arthroplasty: perspectives of surgeons and patients.

To determine the factors influencing surgeons' choice of implants for total hip arthroplasty (THA) and total knee arthroplasty (TKA), 650 surveys were mailed to all active members of the American Association of Hip and Knee Surgeons practicing in the United States; 364 surveys (56%) were completed and returned. Analysis revealed that the average number of total hip and total knee replacements performed by the respondents in 1997 was 81 and 97; there was substantial regional variation. The average number of hip implant and knee implant brands used by these surgeons in 1997 was 2.4 and 1.8. Anticipated improvement in clinical results and cost of components were the most frequently listed reasons for changing brands. Surgeons were also queried about cost reduction programs at their particular institution. The most frequently listed strategies for cost reduction of implants included surgeon cost-awareness programs and volume discounting. More than half of the respondents (53.5%) anticipate manufacturers to decrease the cost of implants in the next 2 years. Most of the respondents (93.7%) currently have the ability to choose a particular implant. About half (46.7%) anticipate losing some or all control of this decision in the next 3 years. These respondents foresee their hospitals requiring the use of a discounted implant in the future. An additional survey was completed by 102 consecutive patients scheduled either for primary THA (64) or primary TKA (38) at our institution. When asked about implant selection, 93.1% responded that their orthopaedic surgeon should choose the prosthesis; 5.9% responded that their physician in consultation with the patient should choose the prosthesis. When asked what should be the primary determinant of implant choice, cost or quality, the overwhelming majority (97.1%) chose quality. A small percentage (2.9%) chose cost and quality. No patient chose cost alone. A large number of patients (84.8%) responded that they would pay additional costs if their insurance companies or health maintenance organizations refused to pay for a better but more expensive implant. Most patients realized how expensive components are, and 51% of the respondents correctly estimated the cost of an implant. Orthopaedic surgeons perceive that they are losing control of implant choice in THA and TKA. Cost of implants is one of the most significant factors influencing which implant is chosen. Patients (the true payors), however, overwhelmingly want their surgeons to choose the implant used at surgery, and they want quality, not cost, to be the primary determinant of this decision.

Arthroplasty, Replacement, Hip↗
PubMed1999

Efficacy of irrigation for removal of particulate debris after cemented total knee arthroplasty.

We studied the amount of particulate debris removed with pulsatile lavage irrigation before and after component implantation in 13 consecutive patients undergoing primary cemented total knee arthroplasty (TKA) done by a single surgeon. Before component implantation, the knees were copiously lavaged with 3 L of pressurized irrigant; all fluid was collected in 1 aliquot using standard wall suction canisters. After cementing the components in place, another 3 L of pressurized irrigant was used; this fluid was collected in 3 sequentially labeled 1-L aliquots. Collected fluids were centrifuged, and the residue was washed, recentrifuged, and dried. Residual particulate debris was quantitated by weight. An average of 537 mg/L (range, 16-1,406 mg/L) of debris were removed before implantation with 3 L of irrigation. An average of 217 mg/L (range, 31-999 mg/L), 52 mg/L (range, 0-189 mg/L), and 49 mg/L (range, 1-185 mg/L) of debris was removed after implantation with each of the additional liters. Using analysis of variance testing, there was a statistically significant difference between the amount of debris removed with 3 L and after 4 L (P = .02) and 5 L (P = .03) of irrigant. There was no statistical difference between irrigation with 5 L and 6 L of irrigation (P = .92). The residua particulate debris was also analyzed to determine the relative amounts of bone-soluable organics and polymethyl methacrylate (PMMA). Before implantation, the residual debris, by weight, consisted of 79% bone and 21% soluable organics. We found on average that after implantation of components the specimens contained 53% bone and 47% PMMA and soluable organics by weight. We believe that despite careful implantation and meticulous cement technique, large amounts of debris, including bone and PMMA, remain after TKA, which require at least several liters of pulsatile lavage to remove. Removal of this particulate debris may decrease third-body polyethylene wear.

Aged↗
PubMed1999

Acetabular fracture associated with cementless acetabular component insertion: a report of 13 cases.

Acetabular fracture during insertion of a cementless acetabular component occurred in 13 patients. The preoperative diagnosis was osteoarthritis in 6 patients, rheumatoid arthritis in 2 patients, avascular necrosis in 3 patients, hip fracture nonunion in 1 patient, and developmental dysplasia of the hip in 1 patient. Several different components were used; however, the acetabulum was underreamed by 1 to 3 mm in all cases. The acetabular fracture was identified in 9 of 13 cases intraoperatively. The fracture was identified on postoperative radiographs for the other 4 cases. Fractures were treated by a variety of means, including the addition of augmentation screws in or around the cup, use of autograft bone at the fracture site, modified postoperative weight-bearing status, and immobilization. In 2 cases, the socket needed to be revised after it progressively migrated and failed. One patient had cup migration, and another had a radiolucent line about the cup but was not symptomatic enough to require revision. In 3 of these 4 cases, the fracture was not identified intraoperatively. Underreaming of the acetabulum and use of an oversized acetabular component has been recommended to improve the initial stability of the acetabular component during total hip arthroplasty. Impaction of an oversized component requires bone to undergo plastic deformation if the cup is to be fully seated. Theoretically, this technique provides improved component stability with enhanced osseous ingrowth into the cup. The 13 cases reported in this study demonstrate that acetabular fracture is a complication that may occur in association with uncemented hip arthroplasty, particularly if oversized components are used. The importance of recognizing acetabular fractures intraoperatively and the need to institute appropriate treatment to ensure a stable acetabular component is emphasized. In patients with osteoporotic bone, line-to-line reaming with use of a cementless acetabular component or insertion of a cemented socket may be considered to avoid this significant complication.

Acetabulum↗
PubMed1998

Conversion of hemiarthroplasty to total hip arthroplasty: can groin pain be eliminated?

In this study 45 patients with groin or buttock pain after hemiarthroplasty were evaluated 2 to 7 years after conversion to total hip arthroplasty. Groin or buttock pain was completely relieved in 36 patients (80%) and partially relieved in an additional 4 patients (9%). After conversion surgery, 9 patients continued to have groin or buttock pain, but no factor could be identified that would predict an unsuccessful result. The hypothesis tested in this study was whether conversion of a hemiarthroplasty to a total hip arthroplasty eliminates groin pain. Because a significant number of patients (up to 20%) will continue to have some groin or buttock pain after conversion surgery, patients should be warned of this contingency before surgery.

Acetabulum↗
PubMed1998

Five-year clinical and radiographic follow-up of the uncemented long-term stable fixation total hip arthroplasty.

Thirty-nine uncemented porous-coated long-term stable fixation total hip prostheses with a minimum 5-year follow-up, were retrospectively reviewed for clinical and radiographic outcome. Clinical evaluation was performed using the modified Harris Hip Score. Additionally, all patients completed a satisfaction questionnaire. Anteroposterior view and lateral view radiographs were obtained and compared with immediate postoperative films utilizing the Hip Society radiographic evaluation form for uncemented implants. The follow-up period averaged 69 months (range, 60-87 months). At the most recent follow-up visit Harris Hip Scores averaged 88 points (range, 68-100 points), with 79% good or excellent results. Of the 8 hips (6 patients) with fair or poor results, 5 patients (6 hips) were Charnley category C patients. All patients were satisfied with their surgery and all, but 2 stated that their function had significantly improved. The incidence of significant thigh pain was 13%. Calcar osteolysis was present in 13 of 39 femurs with the majority of cases being minimal. All but one femoral component demonstrated bone ingrowth. There was no distal femoral osteolysis present and no femoral revisions have been performed or are planned. Acetabular osteolysis was present in 7 of 39 hips, with 4 of the 7 centered around acetabular fixation screws. All patients who had acetabular bone loss had some degree of femoral osteolysis. Thus far, one patient has required acetabular revision secondary to osteolysis. Acetabular osteolysis in this series was more profound than on the femoral side and two other patients are being considered for revision due to pelvic side osteolysis. In conclusion, the uncemented long-term stable fixation femoral component proved to be durable in this series of patients. The circumferential porous coating on the femoral implant may protect against distal osteolysis. A concerning rate of severe pelvic osteolysis and impending failure was noted and may lead to a greater need for revision surgery with longer follow-up.

Arthroplasty, Replacement, Hip↗
PubMed1998

Immediate weightbearing after uncemented total hip arthroplasty.

Radiographic subsidence of the femoral prosthesis and clinical results after unilateral and simultaneous bilateral uncemented total hip arthroplasty were compared. Patients who had bilateral total hip arthroplasty began weight-bearing as tolerated on both lower extremities the day after surgery. Patients who had undergone unilateral total hip arthroplasty were maintained at 10% weightbearing on the operative limb for 6 weeks after surgery. Patients in both groups were matched for age, gender, and weight. Minimal followup was 2 years. There was no difference between the two groups in terms of clinical results. Radiographic assessments were performed immediately after surgery, 6 weeks after surgery, and again at 2 years after surgery. Radiographs were reviewed by a single observer and analyzed with a digitized data recorder. Increased subsidence of the femoral prosthesis within the bilateral group was found at 6 weeks. The mean subsidence of the femoral prosthesis at 6 weeks for the bilateral total hip arthroplasty group was 0.86 mm (range, 0.18-2.60 mm) and for the unilateral group was 0.39 mm (range, 0.07-1.46 mm). However, subsidence occurring between 6 weeks and 2 years averaged 0.50 mm (range, 0.09-1.10 mm) for the bilateral group and 0.54 mm (range, 0.03-0.99 mm) for the unilateral group. This difference was not significant. At the 2-year followup, all femoral prostheses in both groups appeared radiographically stable with evidence of bone ingrowth and no indications of loosening. Thus, immediate weightbearing after bilateral total hip arthroplasty in this study resulted in more initial subsidence (during the first 6 weeks after surgery) of the femoral prosthesis but did not preclude the prosthesis from becoming stable and achieving bone ingrowth. Patients in both groups obtained satisfactory clinical results. Because initial stability and bone ingrowth are factors influenced by prosthesis design, the results of this study may not be applicable to all implants.

Adult↗
PubMed1995

Clinical significance of leg-length inequality after total hip arthroplasty.

Sixty-eight patients were interviewed and examined after total hip arthroplasty (THA) to determine the clinical consequences (patient satisfaction, shoe lift use, gait abnormalities, etc) of leg-length inequality. No patient met clinical or radiographic criteria for revision THA. Minimum follow-up was 2 years, and average follow-up was 6.6 years (range, 2 to 20.5 years). A questionnaire, with specific questions about leg-length inequality, was completed by each patient. Leg-length inequality was determined by orthoroentgenography and compared with clinical measurements of leg length. The average inequality in this series of patients was 9.7 mm. A significant number (32%) of patients were aware of this inequality; the average leg-length inequality in this group was 14.9 mm. More than half of these patients were disturbed by the inequality. The magnitude of leg-length inequality closely correlated with awareness of the inequality, abnormal gait, use of ambulatory assistive devices, the need for a shoe lift, prior leg-length inequality, and revision THA. Clinical measures of leg-length inequality correlated poorly with values determined orthoroentgenographically. The high rate of dissatisfaction among patients with a leg-length inequality and the untoward results associated with this inequality indicate that surgeons performing THA should familiarize themselves with a reliable method for equalizing leg lengths intraoperatively.

Adult↗