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Biomedical subjects

J A Rand

Publications and source records attributed to J A Rand.

At least 37 records · Page 2Linked to original sources
PubMed1996

Comparison of inset and resurfacing patellar prostheses in total knee arthroplasty.

A comparison of 135 resurfacing with 116 inset biconvex patellar components with a single total knee arthroplasty design was performed. At 2.5 +/- 0.5 years postoperatively, patellar tilt in the resurfacing group was 4 degrees +/- 6 degrees compared with 0.5 degree +/- 5 degrees in the biconvex group (p < 0.0001). Lateral patellar subluxation was 6% +/- 10% in the resurfacing group compared with 3% +/- 9% in the biconvex group (p < 0.05). Lateral release was required in 79% of the resurfacing group compared with 56% in the biconvex group (p < 0.0001). Complete patellar radiolucent lines were seen adjacent to 4 biconvex and 2 resurfacing patellar prostheses. Patellar radiolucent lines were seen more frequently in area 1 in the biconvex group compared with the resurfacing group (p < 0.01). An inset patellar implant appears to provide better radiographic alignment than a resurfacing implant, but it has a higher incidence of radiolucent lines.

Adult↗
PubMed1996

Modularity in total knee arthroplasty.

A prospective study was performed of 41 consecutive revisions using a modular total knee arthroplasty design. The Hospital for Special Surgery knee score improved from 52 +/- 16 preoperatively, to 85 +/- 8 at last evaluation. At last evaluation, the HSS knee scores were excellent in 26, good in 14, fair in 1, and poor in 0 knees. The Knee Society pain score improved from 38 +/- 23 preoperatively to 91 +/- 8 at last evaluation. The Knee Society function score improved from 40 +/- 24 preoperatively to 68 +/- 28 at last evaluation. Incomplete radiolucent lines were seen adjacent to 61% of the components, but not adjacent to the long stems. The results were similar with either pressed fit or cemented long stems or posterior cruciate retaining or posterior stabilized articulations of the prosthetic design. Modularity facilitates revision total knee arthroplasty.

Aged↗
PubMed1995

Total knee arthroplasty with the kinematic condylar prosthesis. A ten-year follow-up study.

Of 168 consecutive knees (118 patients) that had been treated with an arthroplasty with use of a kinematic total condylar prosthesis that allowed retention of the posterior cruciate ligament, 119 knees (eighty-four patients) were available for review at a mean of 10.0 +/- 0.7 years after the operation. The Hospital for Special Surgery knee score improved significantly, from a mean of 55 +/- 12 points preoperatively to a mean of 81 +/- 9 points at ten years (p < 0.0001). Radiolucent lines about the patellar component, present in thirty-five of eighty-three knees at the latest follow-up examination, were related to malpositioning of the tibial and femoral components. Six revisions were performed, and four of them were for a loose patellar component. The rate of deep infection was 1 per cent (one knee). Complications occurred in twenty-six knees (22 per cent). With revision as the end point, the rate of survival of the prostheses was estimated to be 96 per cent at ten years. The knee scores, the rate of survival of the implants, and the range of motion of the knees in the current study were similar to those reported previously for patients who had insertion of a total condylar prosthesis with sacrifice of the posterior cruciate ligament and for those who had substitution of the posterior cruciate ligament with a posterior stabilized prosthesis. A prosthesis that has a metal-backed tibial component and that allows preservation of the posterior cruciate ligament provides durable results, but loosening of the patellar component remains a major problem.

Adult↗
PubMed1995

Tibial wedge augmentation for bone deficiency in total knee arthroplasty. A followup study.

This report constitutes a followup of a previous study of 28 knees in 25 patients with metal wedge augmentation for tibial bone deficiency. Those patients were reviewed 2.3 years after surgery; 79% had excellent results, and 21% had good results. Twenty-four knees in 21 patients with a metal wedge augmentation for tibial bone deficiency were reviewed 5.6 years clinically and 4.8 years radiographically after surgery. Clinical results were excellent in 67%, good in 29%, and poor in 4%. The only poor result was in 1 knee that required 2 revision procedures: the first for failure of a metal-backed patellar component and the second for aseptic loosening of the femoral component. Radiolucent lines at the cement bone interface beneath the metal wedge were present in 13 knees. Eleven of those radiolucencies were < 1 mm in width, and 2 were 1 to 3 mm in width. None of those lucent lines were progressive. Metal wedge augmentation for tibial bone deficiency is a useful option. No deterioration of the wedge-prosthesis or wedge-cement-bone interface was seen at midterm followup.

Aged↗
PubMed1994

Intramedullary arthrodesis of the knee after failed total knee arthroplasty.

Eighteen patients (eighteen knees) were managed with an intramedullary arthrodesis after a failed total knee arthroplasty. Twelve knees had had a revision total knee arthroplasty and six, a primary total knee arthroplasty. Three knees had had failure of a hinged prosthesis. In eleven knees, the arthroplasty had failed because of infection. Nine patients had had previous attempts at arthrodesis with external fixation. The average duration of the operation was six hours, and the average blood replacement was 2975 milliliters. A vascularized fibular pedicle graft was used in four patients. At a mean of thirty-seven months after the arthrodesis, sixteen of the eighteen patients had a complete radiographic union. The mean time to union was 5.5 months. Although a high rate of union was achieved in these patients, complications occurred in ten of the eighteen knees and this must be considered. Intramedullary arthrodesis is a successful method of salvage for a failed total knee arthroplasty or one complicated by infection that is not amenable to revision, but it is technically demanding and has frequent complications.

Adult↗
PubMed1994

Evaluation and management of infected total knee arthroplasty.

Infection after total knee arthroplasty is an infrequent but devastating complication. An understanding of the cause of infection, its diagnosis, and potential treatment options is essential to achieve a satisfactory result. The most successful treatment option is reimplantation with an 89% success rate of elimination of infection. However, some individuals require alternative salvage techniques.

Arthrodesis↗
PubMed1994

Cemented long-stem revision total knee arthroplasty.

Theoretical concerns about the use of cemented long-stemmed revision total knee arthroplasty include inducing stress shielding with adverse effects on prosthesis fixation. This study details the clinical outcome of 35 patients with 40 cemented long-stemmed kinematic stabilizer revision total knee arthroplasties at followup evaluation averaging 58.2 months (range, 24-111 months). Of these 40 revision arthroplasties, there were 25 long-stemmed tibial components and 38 long-stemmed femoral components. The Knee Society pain score improved from a preoperative value of 38 points (range, 4-80 points) to 83 points (range, 33-100 points) at last evaluation. The Knee Society function score improved from a preoperative value of 46 points (range, 5-100 points) to 64 points (range, 0-100 points) at last evaluation. Initial postoperative radiographs showed tibial bone-cement radiolucencies in 5 knees, but at final followup none of these radiolucencies had progressed. Radiolucencies developed in 5 additional tibial components by the time of final followup, but these were all incomplete and < 1 mm in width. Two femoral components had initial postoperative radiolucencies. These radiolucencies remained stable in 1 knee, whereas the other knee had asymptomatic radiographic loosening. Incomplete radiolucencies of < 1 mm developed in 3 additional femoral components at final followup. The incidence of tibial radiolucencies of 32% in the present study is similar to the incidence of radiolucencies with a nonstemmed revision cemented total knee arthroplasty, with the same prosthetic design, previously reported from the authors' institution.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Treatment of the infected total knee arthroplasty with insertion of another prosthesis. The effect of antibiotic-impregnated bone cement.

Eighty-six patients with 89 infected total knee arthroplasties were treated with insertion of another prosthesis. Treatment was not according to an established protocol for parameters, such as delay between removal of the infected prosthesis and insertion of the new prosthesis, duration of antibiotics, use of antibiotic-impregnated cement spacers or beads, and use of antibiotic-impregnated cement for prosthetic fixation at revision surgery. Final followup averaged 52 months (range, 6-126 months). Complications occurred in 30 (33.7%) knees, with recurrent deep infection developing in 10 (11.24%) knees. Patient age, medical diagnosis, type of microorganism, duration of parenteral antibiotics, delay between the resection and revision surgery, and use of antibiotic-impregnated cement spacers or beads were not correlated with the cure rate of infection. Use of antibiotic-impregnated bone cement for prosthesis fixation at revision surgery was the only variable that correlated with the cure rate of deep infection. Seven (28%) of the 25 knees without antibiotic-impregnated cement for prosthesis fixation developed recurrent infection compared with 3 (4.7%) of 64 knees with antibiotic-impregnated cement for prosthesis fixation. This difference was statistically significant (p = 0.0025, log-rank test).

Adult↗
PubMed1993

Comparison of metal-backed and all-polyethylene tibial components in cruciate condylar total knee arthroplasty.

An evaluation of 78 knees in 63 patients using the cruciate-sparing total condylar prosthesis was performed. At a mean of 10 years following the arthroplasty there were 86% good or excellent results in knees with an all-polyethylene tibial component compared to 95% with a metal-backed tibial component (NS). Survivorship at 10 years using an endpoint of revision was 96% (NS) in both groups; using an endpoint of revision or poor knee score was 85% (NS) in the metal-backed compared to 92% (NS) in the all-polyethylene groups; using an endpoint of revision, poor knee score, or complete radiolucent line was 85% in the metal-backed compared to 90% (NS) in the all-polyethylene groups. There were no significant differences in the frequency of radiolucent lines at the last evaluation. Two percent of the tibial components in the metal-backed group had complete radiolucent lines compared to none in the all-polyethylene group. The cruciate-sparing total condylar prosthesis provides satisfactory results with no significant differences between the metal-backed or all-polyethylene tibial components at 10 years.

Adult↗
PubMed1993

Fractures of the femoral shaft adjacent to long stem femoral components of total hip arthroplasty: report of seven cases.

Seven femoral shaft fractures adjacent to the distal aspect of long stem revision femoral components of total hip arthroplasty were evaluated at a mean of 6 years (range: 2 to 12) after fracture. Nonoperative treatment with a spica cast was used in four patients. Complications were delayed union in two patients and malunion in two. Operative treatment included revision and bone grafting in one patient and open reduction and internal fixation in two. Plate fracture and delayed union occurred in one patient. Operative treatment resulted in no malunions and earlier recovery of function than with nonoperative management. Femoral shaft fractures adjacent to long stem total hip arthroplasties are difficult to manage; the complication rate is 71%.

Aged↗
PubMed1993

Extensive osteolysis around an aseptic, stable, uncemented total knee replacement.

Extensive osteolysis occurred around an aseptic, well-fixed, stable, uncemented total knee prosthesis. At the time of revision, tibial polyethylene wear and minimal metal-on-metal contact were present. A hypertrophic synovium-like membrane abutted bone in regions of osteolysis. Examination of this membrane revealed polyethylene-wear debris and significant levels of chromium, cobalt, and titanium. Wear debris--polyethylene, metal, or a combination of both--may be responsible for the osteolytic process in this case.

Bone Cements↗
PubMed1993

A prospective randomized study of a collar versus a collarless femoral prosthesis.

A prospective, randomized study of 44 collared versus 40 collarless cemented HD-2 total hip arthroplasties (THAs) was performed in 84 patients. Seventy patients were examined at an average of 4.6 years after surgery. Five hips have required, or are scheduled to have, revision arthroplasty: two with collared prostheses and three with collarless prostheses. Good collar contact with the proximal medial femur was achieved in 47% of the collared prostheses. No patient with good contact has required or is scheduled to have revision hip surgery. Radiolucent lines were greater in both frequency and width in Gruen Zones 2 and 7 in patients with a collarless prosthesis. Loss of endosteal height of the femoral neck was 3.5 mm in patients with collarless prostheses and 1.7 mm in patients with collared prostheses. Loss in height of the femoral neck was 2.6 mm in patients with collared prostheses with poor bone contact and 0.7 mm in patients with collared prostheses with good bone contact. The mean preoperative and postoperative Harris hip scores for the collarless group and for the collared group were not statistically different. There were no statistically significant differences in acetabular position, the incidence of acetabular radiolucent lines, or femoral subsidence between patients treated with collared or collarless prostheses. This study demonstrates that it is possible to stress the proximal medial portion of the femur with a collared prosthesis. Furthermore, a significant increase is identified in both the frequency and width of radiolucent lines in patients with collarless prostheses in Zones 2 and 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1993

Isolated patellar component revision of total knee arthroplasty.

Forty-two knees in 41 patients required isolated patellar component revision of a total knee arthroplasty (TKA). Revision was performed for loosening in 14 knees, wear to metal backing in 13, fracture of the fixation peg in seven, dissociation of polyethylene from metal backing in two, anterior knee pain in two, patellar instability in two, and component malposition with fat pad proliferation in two. Thirty-six knees were evaluated two to eight years after patellar revision. The Hospital for Special Surgery knee scores improved from an average of 71 preoperatively to 81 postoperatively. Eighteen knees were excellent; 12, good; four, fair; and two, poor. Complications associated with patellar revision included late patellar fractures in five knees, patellar instability in three, peroneal nerve palsies in two, patellar polyethylene wear to metal backing in two, infection in one, and extensor lag in one. This seemingly straight-forward procedure is associated with a high complication rate.

Adult↗
PubMed1993

V-Y quadricepsplasty in total knee arthroplasty.

The results in 14 consecutive patients (16 knees) who have had total knee arthroplasty (TKA) with a V-Y quadricepsplasty were reviewed. There were eight men and six women with an average age of 66.2 years. Nine patients (ten knees) had revision arthroplasty and five patients (six knees) had primary arthroplasty. Nine of the 14 patients were examined and evaluated in the biomechanics laboratory using the modified Cybex-II system at a mean of three years from surgery. Using the knee rating score of the Hospital for Special Surgery, there were two excellent, ten good, two fair, and two poor results. The average active range of motion was 4 degrees to 85 degrees. Biomechanical testing revealed statistically significant weakness in extension compared with the contralateral side only at test speeds of 120, 180, and 240 degrees per second in those patients who had contralateral normal knees. The affected side at other test speeds were weaker but did not reach statistically significant weakness when compared with the contralateral knee. Comparing V-Y quadricepsplasty to normal medial parapatellar TKA patients, the extensor mechanism was weaker in the V-Y group but not to a significant degree. If one requires a V-Y quadricepsplasty during TKA, one can expect near normal active extension and moderate weakness in extension. Knee scores reflect the difficult reconstructive challenges that are inherent in patients who require a V-Y quadricepsplasty.

Activities of Daily Living↗