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Biomedical subjects

T H Mallory

Publications and source records attributed to T H Mallory.

At least 73 records · Page 4Linked to original sources
PubMed1990

Malignant fibrous histiocytoma after total hip arthroplasty. A case report.

Technical advancements in total joint arthroplasty have led to components of varied design and substance and to increased longevity of the implanted components. Along with increased longevity of the implants comes concern about how these synthetic materials affect the tissues of the host. Experimentally, several materials currently used in implantable components have been shown to be potentially carcinogenic. Clinically, 12 cases of malignancy have been reported previously in association with orthopedic implants; of these, four were malignant fibrous histiocytomas (MFH). This report describes an additional case of MFH occurring in a patient who had multiple hip arthroplasties over a period of 15 years. While 13 malignancies associated with orthopedic implants could certainly be coincidental in view of the vast number of implanted orthopedic devices, each incidence of malignancy associated with an implant should be considered significant in determining any meaningful trends and relationships.

Adult↗
PubMed1990

Controlled perforation. A safe method of cement removal from the femoral canal.

Removal of cement from the femoral canal during total hip revision arthroplasty continues to be very challenging. The technique is described using multiple 9-mm perforations placed at least 5 cm apart on the anterior surface of the femoral shaft. The tip of the revision stem should be at least 5 cm distal to the most distal perforation. From January 1984 to December 1986, 219 cases of revision total hip arthroplasties were performed using this technique; the incidence of ipsilateral postoperative femoral fractures was nine out of 219. Eight of these fractures were at the tip or distal to the femoral prosthesis and were associated with trauma. One fracture occurred through a perforation site and had an associated fracture of the femoral component. This method appears to be a reliable and safe method of cement removal from the femoral canal.

Arthroplasty↗
PubMed1989

Intraoperative femoral fractures associated with cementless total hip arthroplasty.

Between 1982 and 1986, 56 femoral fractures associated with cementless total hip arthroplasty (THA) were evaluated and compared to a randomly selected cementless THA control group without fractures. Depending upon the femoral shaft location, these fractures were classified as Types I, II or III. There were 45 (80%) Type I, 9 (16%) Type II, and 2 (4%) Type III fractures. Patient evaluations were quantified using a modified d'Aubigne-Harris scoring system. Nonparametric statistical methodology was used for fracture and control group comparisons. Treatment protocols were divided into various modalities, depending upon fracture classification. Type I and Type II fractures have no long-term prognostic hazards associated with them (P greater than 0.1), while Type III fractures appear to have analogous clinical results (sample size was too small for statistical analysis).

Adult↗
PubMed1989

Use of the Greenfield filter to prevent fatal pulmonary embolism associated with total hip and knee arthroplasty.

We inserted a Greenfield filter prophylactically in forty-two of approximately 4,000 patients who were about to have a total hip or knee replacement, or both, and who were at high risk for pulmonary embolism (Group I). The filter was implanted postoperatively in twenty-four additional patients who had thromboembolic complications or in whom anticoagulation was contraindicated (Group II). None of the patients in Group I and only one in Group II had a fatal pulmonary embolism. Use of the Greenfield filter is a safe, easy, and effective method of preventing fatal pulmonary embolism in selected patients: those who are at exceptionally high risk for thromboembolism, as a method of preoperative prophylaxis; those who have had a thromboembolism and in whom therapeutic anticoagulation is contraindicated; and those who have complications secondary to therapeutic anticoagulation.

Adult↗
PubMed1989

Total joint replacement: both a miracle and a disappointment.

Total joint arthroplasty has become a successful therapy for patients with debilitating arthritis of the major weight-bearing joints. However, by current standards, the life of a total joint implant is approximately 10 to 15 years. Older, more sedentary patients enjoy greater and longer-term success than younger, active patients. Eventually, most implants fail because of component loosening. Currently, efforts to obtain longer-term implant stability are focused on achieving bone growth into the implanted components. A new process of plasma-spraying hydroxyapatite--an entirely biocompatible, bioceramic material--onto porous, titanium alloy components promotes bone ingrowth into the components resulting in implant fixation, which is superior to current methods of cemented or cementless fixation. Early results suggest that hydroxyapatite-bioingrowth fixation may be the start of a new era in joint implant surgery.

Arthritis↗
PubMed1989

Aseptic loosening in total hip arthroplasty secondary to osteolysis induced by wear debris from titanium-alloy modular femoral heads.

Since 1984, we have used components made of titanium alloy for total joint arthroplasty. Recently, two patients needed revision hip arthroplasty, approximately three years after the initial procedure, because of aseptic loosening secondary to severe osteolysis that had been induced by metallic debris. Although implants made of titanium alloy have many favorable qualities--most importantly, superb biocompatibility--the alloy is more susceptible to wear by particles of acrylic cement and tends to generate more polyethylene wear than do components made of stainless steel or chromium-cobalt. A new process of implanting ions has reportedly improved resistance to wear as well as fatigue properties and has enhanced the resistance to corrosion of the implants. Although, to our knowledge, only in vitro studies of this process have been reported to date, we recommend avoiding the use of components made of titanium alloy in which ions have not been implanted. We suggest considering the possibility of osteolysis secondary to appreciable metallic debris in patients who have aseptic loosening of titanium-alloy components that were not implanted with ions.

Adult↗
PubMed1988

Mittelmeier ceramic total hip arthroplasty. A retrospective study.

Ceramic, featuring low reactivity and excellent durability, is an excellent material for biologic implant. The authors studied the Mittelmeier ceramic total hip prosthesis in 62 patients (69 hips), with an average follow-up period for the surviving cases of 37.6 months (SD = 9.04; range, 24-52 months). As a result of aseptic loosening, 19 cases (27%) were revised, with an average time to revision of 26.2 months (SD = 8.8; range, 14-38 months). Proper femoral interference fit, measured as 90% of the intramedullary canal fill, was associated with better clinical scores, fewer radiolucencies on follow-up roentgenogram, and decreased failure due to aseptic loosening. In this study, there appeared to be no adverse effects of ceramic as a biomaterial. Design modifications may lead to better fixation and, hence, long-term durability.

Ceramics↗
PubMed1988

Prophylactic use of a hip cast-brace following primary and revision total hip arthroplasty.

A hip cast-brace was routinely applied to 67 patients undergoing 37 revision and 30 primary total hip arthroplasties. In the revision group, 78% of the patients were discharged by the tenth postoperative day; the average period in the cast-brace was 23 days. One patient developed deep venous thrombosis. Dislocation occurred in three patients who had undergone previous revision total hip arthroplasties. Of these three patients, one dislocated while wearing the cast-brace. In the primary group, 72% of the patients were discharged by the eighth postoperative day and average time in the cast-brace was 15 days. One developed deep venous thrombosis; no dislocations occurred.

Braces↗
PubMed1988

Works in progress #2. Threaded acetabular components. Design rationale and preliminary clinical experience.

Two design rationales for threaded acetabular components, the S-ROM Anderson cup and S-ROM SuperCup, are discussed. Components have been followed for at least six months, with a range of six to 24 months. The average follow up is nine months. One hundred components in 96 patients had sufficient follow up and full clinical and roentgenographic evaluations to be included in this study. The 100 hips were divided into four groups based on S-ROM Anderson cup versus S-ROM SuperCup and on primary versus revision. Each hip was evaluated on a clinical and radiologic basis. Based on clinical and roentgenographic evaluations of both the primary and revision situations of the S-ROM SuperCup, consistently good to excellent results were observed. To date, no case has undergone revision for clinical or roentgenographic failure. Dramatic pain relief was exhibited by 96% of patients. Although early results are very encouraging, longer follow ups are necessary.

Acetabulum↗
PubMed1988

Fracture of a metal-backed acetabular component in total hip arthroplasty. A case report.

Metal-backed acetabular components offer the advantage of a lower incidence of loosening. The case of a 33-year-old man emphasizes the potential problem of fracture of both the polyethylene and metal-backed structures. Although this case report may represent an unusual and infrequent occurrence, it emphasizes a potential failure mode for acetabular components with metal backing. While fracture of the polyethylene has been previously reported, little thought has been given to the further potential of fracture of metal-backed support. The clinical profile as well as the roentgenographic appearance of such a phenomenon is presented for further sophistication of the surgeon when dealing in the challenging area of hip arthroplasty.

Acetabulum↗
PubMed1988

Preparation of the proximal femur in cementless total hip revision.

With an increased incidence of revision for the failed cemented total hip arthroplasty, techniques of revision surgery need meticulous attention to detail. Although the causes of the failed cemented total hip arthroplasty are many, they tend to follow characteristic patterns. The proximal femur can be exposed through an extensive muscle split incision, which offers a complete circumferential view of the femur. The cement removal is enhanced by controlled perforation using high-speed drills. Classification of bony deficits of the proximal femur can be divided into Type I, including intact cortex and medullary content; Type II, in which there is intact cortex but deficient medullary content; and Type III, in which deficits of both the cortex and medullary canal are present. Prosthetic selection is based on residual bone stock. In general, cementless fixation is advocated, with distal fixation using long-stem devices. Augmentation of bone deficits requires the use of segmental prosthetic replacement or fresh-frozen allografts. One hundred sixty patients were followed for two to six years. Satisfactory results have occurred in over 90% of the patients; better results are anticipated in patients with minimal bone deficits. Aseptic loosening requiring rerevision has occurred in 5% of the patient population. Understanding the dynamics of failure and the residual bone deficits allows one to manage the failed cemented total hip arthroplasty with greater efficiency and predictability.

Bone Cements↗
PubMed1987

Extensile exposure of the hip for revision arthroplasty.

The authors describe a lateral approach to the hip without trochanteric osteotomy that allows sufficient access to the femur and acetabulum for revision total hip arthroplasty. When bone loss is extensive, this approach permits massive autograft/allograft arthroplasty of the proximal femur and acetabulum. This approach follows anatomic muscle planes, maintains abductor function, and allows wound closure with a viable muscle cuff around the acetabulum and upper femur. The exposure is adequate for anatomic placement of components and correction of leg length discrepancy.

Follow-Up Studies↗
PubMed1987

Femoral cement removal in revision total hip arthroplasty. A biomechanical analysis.

A technique of femoral cement removal in revision total hip arthroplasty is described and biomechanically evaluated. Two 9-mm holes are drilled anteriorly through the proximal femoral cortex before cement is removed. These holes permit direct visualization of the medullary canal and help to prevent eccentric reaming or inadvertent perforation with the power drill. They also provide portals for enhanced irrigation, illumination, and cement removal. For assessment of the effect of cortical perforations on bone strength, 12 cadaveric femurs containing cemented prosthetic stems were analyzed. The femurs were stressed at various loads on the Instron Materials Testing Machine (Instro Engineering Corporation, Kenton, MA) under conditions simulating single-limb stance. The stress concentrations were significantly higher about laterally drilled holes than about those located anteriorly. When loaded to failure, all fractures occurred at or below the prosthetic stem tip. No fractures occurred in the proximally placed drill holes. A finite element model showed that two holes kept at least two hole diameters apart did not cause cumulative stress concentration.

Biomechanical Phenomena↗
PubMed1987

Arteriovenous fistula with false aneurysm of the inferior medial geniculate artery. A complication of total knee arthroplasty.

Two cases of traumatic arteriovenous fistula with false aneurysm of the inferior medial geniculate artery are reported as a complication of total knee arthroplasty. Both cases were diagnosed within the first two months following the knee surgery. Diagnosis in both cases was confirmed by arteriography. Surgical excision of this lesion with ligation of the inferior medial geniculate artery resolved both of these complications. Strict hemostasis in the region of the inferior medial geniculate artery following subperiosteal release of the medial ligaments in total knee arthroplasty should prevent this complication.

Aged↗
PubMed1987

Femoral component geometry. A factor in total hip arthroplasty durability.

The theoretically conceived geometric design for femoral components, including a longer length, an extended width, and a stiffer modulus, is expressed in the clinical design of the Buck-32 prosthesis. This prosthesis was used in 110 patients with 122 hip arthroplasties between 1975 and 1979, giving a follow-up period of five to nine years (average, 7 years). Femoral loosening requiring revision surgery occurred in 2.3% of the patient population. Radiolucencies were noted in 24% of the cases but were progressive in only 17%. Complications were minimal, as were bone changes about the prosthetic units. There is clinical evidence in the literature, substantiated by this study, that geometric design does influence the durability of a cemented femoral component.

Adult↗
PubMed1984

Total articular replacement arthroplasty. A clinical review.

Sixty-four total articular replacement arthroplasties were performed in 60 patients with an average follow-up period of 24 months. Ninety-three percent of the patients had little or no pain at the time of follow-up examination; 83% of the patients were able to walk unlimited distances; 97% of the patients had a postoperative flexion range of 90 degrees or greater. The incidence of progressively increasing radiolucency at the bone-cement interface in the acetabular area was disturbingly high. There was also a progressive occurrence of bone sclerosis along the lateral border of the prosthetic stem, indicating that the stem provoked bony changes in response to stress transfer. Despite these responses, this procedure has shown better results than those in which other types of conservative or resurfacing devices were used during a two-year evaluation period.

Adult↗