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Biomedical subjects

M A Mont

Publications and source records attributed to M A Mont.

At least 73 records · Page 4Linked to original sources
PubMed1997

Proximally coated ingrowth prostheses. A review.

Proximally coated femoral components for cementless total hip replacement were conceived in the early 1980s in response to the proximal stress shielding that was seen with extensively coated devices. The main purpose of this study was to analyze whether these prostheses remain viable options based on the results of presently used devices, while detailing the problems encountered with first generation devices. The evolution of these designs and how they were modified in response to early problems, was reviewed. Initial iterations were less successful because they were sometimes not stable, had problems with thigh pain, and progressive osteolysis. However, second generation devices with greater than 5 years clinical experience seem promising and have shown very low aseptic loosening rates (1%-3%), and less thigh pain (under 5% in most studies). The reader still must await longer term studies to know whether progressive osteolysis will be a problem. These encouraging midterm results can be attributed to improved geometry, instruments, and technique which ensure initial implant stability. Proximal coating must be circumferential, to seal the diaphysis from were debris. After incorporating design changes in response to the significant failures of early devices, the concept of proximal coating for cementless femoral stems seem viable, as long as the twin requirements of circumferential coating and rigid initial stability are realized.

Arthroplasty, Replacement, Hip↗
PubMed1997

A second-generation cementless hip prosthesis: improved results over the first-generation prosthesis.

Forty-two patients who had a Porous Coated Anatomic (PCA) "E" series, second-generation, cementless hip arthroplasty (Howmedica, Rutherford, NJ) were compared with 42 patients who had a first-generation PCA prosthesis. Patients were directly matched for age, sex, diagnosis, weight, Charnley functional status, and duration of follow-up. All of the operations were done by the same two surgeons, who used the same operative approach and the same postoperative rehabilitation plan. All of the patients were followed up for at least 5 years (range, 60 to 76 months). In the "E" series group, there were 41 of 42 (98%) good and excellent clinical results with a mean Harris hip score of 94 points (range, 46 to 100 points); the first-generation group had 34 of 42 (81%) good and excellent clinical results and a mean Harris score of 81 points (range, 42 to 100 points) (P = 0.001). There was one acetabular component revision in the "E" series group (2%), which can be compared with eight revisions (19%) in the first-generation group (P = 0.012). The incidence of femoral radiolucencies was 19% (eight hips) for the "E" series group compared with 50% (21 hips) in the first-generation group (P = 0.009). The radiolucencies in the "E" series group were small, nonprogressive, and confined typically to zone I. We believe that the improvements in design of the "E" series component may account for these differences.

Adult↗
PubMed1996

Cementless total knee arthroplasty in obese patients. A comparison with a matched control group.

The heaviest 45 patients (50 knees) who underwent cementless total knee arthroplasty were compared with a matched control group of 45 total knee arthroplasty patients (50 knees) with respect to clinical and radiographic data. Surgery was performed over a 10-year period (1980-1989) and follow-up evaluation averaged 7 years (range, 2-11 years). The control group consisted of nonobese patients matched to the obese group with respect to age, sex, diagnosis, preoperative deformity, and length of follow-up evaluation. Clinical evaluation was made using the Knee Society rating scale as well as an analysis of multiple other clinical parameters. Radiographically, each patient was evaluated with long-standing anteroposterior views, lateral and patellar views, and spot fluoroscopic views of the involved knee. This evaluation included an analysis of lucencies, bead shedding, and prosthetic alignment. The final average clinical score in the obese group was 88 points with four revisions, and that for the control group was 91 points with two revisions. There were no significant differences in the combined percentage of good and excellent results between the two groups. On the basis of the results of this study, it is believed that weight as a factor by itself should not compromise the early (7-year average follow-up period) results of total knee arthroplasty.

Adult↗
PubMed1996

Core decompression versus nonoperative management for osteonecrosis of the hip.

A complete review of the literature disclosed that there were 42 reports of 2025 hips treated by either core decompression (1206 hips) or nonoperative management (819 hips), excluding electrical stimulation, for osteonecrosis of the femoral head. The peer-reviewed published reports included general surveys, prospective studies, and multicenter studies, but excluded case reports. Satisfactory clinical results were reported in 63.5% of hips in 24 studies of core decompression and in 22.7% of hips in 21 studies of nonoperative management. When looking at only precollapse hips, there were 71% versus 34.5% good results, respectively. Recalculation excluding reports by the 4 centers that do the most core decompressions (and report the best results) showed a clinical success rate for core decompression of 53% versus 22.7% for the nonoperatively treated group. Investigators of multiple studies have reported that nonoperative management leads to extremely poor results. Core decompression has been reported to have a notable effect on the natural history and clinical progression in early stages of osteonecrosis of the femoral head. In view of the limitations of this data, further clarification of this effect only can be obtained by large prospective randomized studies.

Femur Head Necrosis↗
PubMed1996

Partial denervation for persistent neuroma pain around the knee.

The authors present the results of denervation procedures treatment for 70 patients with persistent knee pain after total knee replacement, trauma, or osteotomy. In patients with total knee arthroplasty, aseptic loosening, sepsis, ligamentous instability, malalignment, and polyethylene wear had to be systematically ruled out as the source of pain. In patients with nontotal knee arthroplasty, arthrosis, synovitis, ligamentous instability, and meniscal derangement had been excluded as a source of pain. All candidates for the procedure had a successful selective nerve block. Sixty of the 70 (86%) patients were satisfied with the denervation procedure as judged by direct questioning and a reduction in their preoperative pain visual analog score of 5 or more points. The average Knee Society score improved from a preoperative mean of 51 points (range, 40-62 points) to a followup mean of 82 points (range, 15-100 points). Forty-nine of 70 (70%) patients had final Knee Society objective scores greater than 80. There was no difference in patient satisfaction whether the followup period was less than 2 years or more than 2 years. Selective knee denervation is indicated in the management of intractable knee pain after exhaustion of traditional approaches to any structural or infectious etiologies and after successful selective nerve block.

Adult↗
PubMed1996

Exploration of radiographically normal total knee replacements for unexplained pain.

Twenty-seven patients underwent exploration of their total knee replacements because of severe debilitating pain of an unknown cause. The group was further subdivided into (1) patients who had painful knees with range of motion greater than 80 degrees and (2) patients who had painful knees with decreased range of motion (< 80 degrees arc). At final followup, there were 11 excellent and good results (41%) with 16 fair or poor results (59%). For the 15 patients with decreased range of motion, 9 of 15 knees (60%) had good or excellent results. Range of motion arc improved from a preoperative 43 degrees average to a 81 degrees average. For the pain only group, there were only 2 excellent or good results (17%). Poor results were encountered in 6 of 7 patients (86%) in whom a cementless prosthesis was converted to a cemented prosthesis. If a problem was identified at surgery, only 3 of 12 knees (25%) had successful outcomes.

Adult↗
PubMed1996

Osteonecrosis of the talus: treatment by hindfoot fusion.

The results were reviewed for 11 ankles (10 patients) that had been treated with various hindfoot arthrodeses because of symptomatic osteonecrosis of the talus. Follow-up averaged 6.5 years (range, 2-15 years). A functional assessment using a modified Mazur grading system was performed both before surgery and at final follow-up. Data were also collected on the duration of the procedure, intraoperative findings, and the patient's assessment of postoperative cosmesis (excellent, good, fair, or poor). Radiographs were analyzed to determine the interval from the procedure until bony union. Nine of the 11 arthrodeses (82%) fused with the primary procedure and achieved excellent Mazur ratings (mean, 86 points; range, 81-90 points). The average interval until radiographic fusion was 7 months (range, 4-13 months). All eight patients (nine fusions) with successful fusions graded their cosmetic outcomes as excellent or good. The average length of the procedure was 148 minutes (range, 130-300 minutes), compared with an average of 92 minutes (range, 62-151 minutes) for ankle arthrodeses performed by the same surgeons in rheumatoid or osteoarthritic ankles (P < 0.001) and 102 minutes (range, 75-164 minutes) from a report in the literature. Two of the procedures were complicated by nonunions secondary to infections. In one patient, after treatment by debridement and intravenous antibiotics, reinfection and chronic osteomyelitis developed with a subsequent below-knee amputation. The other patient was treated successfully with debridement, antibiotics, and subsequent revision arthrodesis, which fused solidly at 9 months with an excellent result. We conclude that hindfoot arthrodeses for osteonecrosis can be technically demanding, but, despite having a long time to bony union, they can have an excellent clinical outcome.

Adult↗
PubMed1996

Corrective osteotomy for osteonecrosis of the femoral head.

We reviewed the long-term results of thirty-seven corrective osteotomies that had been performed for osteonecrosis of the femoral head that was stage II or III according to the classification of Ficat and Arlet. At a mean of 11.5 years (range, five to eighteen years) postoperatively, twenty-eight hips (76 per cent) had a good or excellent result according to the Harris hip-scoring system, and nine (24 per cent) had a fair or poor result and subsequently needed a total hip arthroplasty. Six of the nine failures were in the seventeen hips of patients who had received corticosteroids. Conversely, of the twenty hips of patients who had not received corticosteroids, seventeen (85 per cent) had a good or excellent result as determined by the Harris hip score at the latest follow-up evaluation. Five of the six hips that had had a combined necrotic angle of more than 200 degrees preoperatively had subsequent collapse of the femoral head. Of the thirty-one hips that had had a combined necrotic angle of less than 200 degrees preoperatively, twenty-seven (87 per cent) had a good or excellent clinical result. There were five complications. Three non-unions and one cutout of the compression screw were successfully treated, and these hips had an excellent clinical result at the time of the latest follow-up. The fifth complication was osteomyelitis and led to a poor result. The results of this study suggest that corrective intertrochanteric osteotomy is a successful treatment for Ficat and Arlet stage-II or III disease if the patient has a small or medium lesion (a combined necrotic angle of less than 200 degrees) and is not receiving continuous high doses of corticosteroids.

Adolescent↗
PubMed1996

The operative treatment of peroneal nerve palsy.

We retrospectively reviewed the results of operative decompression for peroneal nerve palsy in thirty-one patients who had been managed between 1980 and 1990. All patients had been managed non-operatively for at least two months after they had initially been seen. Intraoperatively, we found epineurial fibrosis and bands of fibrous tissue constricting the peroneal nerve at the level of the fibular head and at the proximal origin of the peroneus longus muscle. At a mean of thirty-six months (range, twelve to seventy-two months) postoperatively, thirty (97 per cent) of the thirty-one patients reported subjective and functional improvement and were able to discontinue the use of the ankle-foot orthosis. In contrast, only three of nine patients who had been managed non-operatively reported subjective and functional improvement (p < 0.01). Peroneal nerve palsy does not always resolve spontaneously; if it is left untreated, the loss of dorsiflexion of the ankle and persistent paresthesias can result in severe functional disability. Therefore, if non-operative measures do not lead to improvement within two months, we believe that operative decompression should be considered.

Adolescent↗
PubMed1996

Intraoperative custom press-fit and standard press-fit femoral components in total hip arthroplasty. A comparison of surgery, charges, and early complications.

A consecutive group of 60 patients who had intraoperative custom press-fit total hip arthroplasties (67 hips; Identifit, Thackray, London, United Kingdom) was compared with a similar group of 60 patients who had standard press-fit arthroplasties (66 hips; McCutchen, Wright Medical Technologies, Arlington, Tennessee) to determine if there were differences in operative time and charges, as well as early complications and early radiographic results. The unilateral intraoperative custom group had an average anesthesia time of 3 hours, 39 minutes, an operating time of 2 hours and 26 minutes, and a blood loss of 725 mL. The averages for the standard group included an anesthesia time of 2 hours, 19 minutes, a surgical time of 1 hour, 25 minutes, and a blood loss of 480 mL. By 6 months after surgery, 49 (73%) in the custom group had subsidence of 2 mm or more, compared with 10 hips (15%) in the standard group. The custom group had 17 early postoperative complications versus 3 in the standard group. The charge for the hospital stay averaged $19,950 for the custom group and $14,322 for the standard group. At the present time, the high incidence of complications and the increased charges make the intraoperative custom hip replacement an unlikely first choice of recommendation.

Adult↗
PubMed1996

Avascular necrosis of the talus treated by core decompression.

We reviewed 11 patients (17 ankles) who had had core decompression for symptomatic avascular necrosis of the talus before collapse. The Mazur grading system was used to assess function preoperatively and at final follow-up, and radiographs were graded according to the Ficat and Arlet (1980) classification modified for the ankle. At a mean follow-up of seven years (2 to 14) 14 ankles (82%) had an excellent or good outcome (Mazur scores > 80 points; pain scores > 40 points (41 to 50). The other three ankles required tibiotalar fusion at a mean of 13 months (5 to 20) after core decompression. We conclude that core decompression is a viable method of treatment for symptomatic avascular necrosis of the talus before collapse.

Adult↗
PubMed1995

History of the contralateral knee after primary knee arthroplasty for osteoarthritis.

Published reports of series of total knee replacements vary between 20% and 75% in the percentage of patients eventually having bilateral replacements. There are no data in the literature on the predicted course of the contralateral knee for patients presenting for total knee replacement. This study reviewed the history of the contralateral knee in patients with a diagnosis of osteoarthritis presenting for unilateral primary total knee arthroplasty. The current study group comprised 185 patients who had either a minimum 5 year followup (range 5-12.5 years) or who were known to have had a second knee arthroplasty before 5 years. Evaluation included a full clinical and radiographic examination of the contralateral knee at index arthroplasty and at final followup. Of the 185 patients, the contralateral side initially was asymptomatic in 36%, mildly symptomatic in 16%, moderately symptomatic in 28%, and severely symptomatic in 20%. Seventy-nine (43%) knees eventually underwent contralateral arthroplasty. Ninety-three percent of patients who had moderate or severe symptoms and severe radiographic arthritis of the contralateral side at the time of presentation later underwent total knee replacement. However, patients who presented initially with mild symptoms or who had no symptoms had only a 9% incidence of knee arthroplasty.

Adult↗
PubMed1995

Radiographic characterization of aseptically loosened cementless total knee replacement.

From January 1980 to December 1992, 655 cementless total knee arthroplasties with the PCA total knee system were done at the authors' institution. Thirty of these knees have been revised for aseptic loosening of either tibial or femoral components or both. Patients in the failed arthroplasty group were matched directly to a control group with well-functioning, stable and painless cementless total knee prostheses (Knee Society objective score, > 90 points). In this study, the authors analyzed any alignment differences between the 2 groups of knees. Special attention was given to the postoperative radiographs to evaluate for potential predictors of success versus failure. Multiple radiographic parameters were measured for each knee and included measures of frontal alignment, sagittal alignment, rotation, percent prosthetic coverage, and cortical thickness (denoted as the cortical-cancellous index). On univariate analysis, no individual radiographic parameter was significantly different in the failure group versus the control group. However, multivariate analysis indicated that certain combinations of abnormal parameters were significantly higher in the failed group than the control group. These parameters included measures of frontal and sagittal plane component alignment. The summated abnormal parameters per patient averaged 3.67 (range, 1-7) for the failure group and 1.80 (range, 0-7) for the control group.

Activities of Daily Living↗
PubMed1995

Partial denervation for persistent neuroma pain after total knee arthroplasty.

Despite the high percentage of patients who are satisfied completely with the results of total knee arthroplasty, there is a small group who remain disabled because of persistent neuroma pain. Recently, a better understanding of the innervation of the skin and capsule around the human knee joint has provided a theoretical basis for denervation in this group of patients. Fifteen patients were identified who had persistent or worse knee pain for > 6 months after total knee arthroplasty. In each patient, component loosening, malalignment, knee instability, and infection had been excluded systematically as a source of pain. Pain was evaluated preoperatively with the Knee Society Functional Score Questionnaire and a visual analog scale. To be selected for surgery, each patient must have had a reduction by 5 points on the visual analogue scale for pain after undergoing selective nerve blocks. Postoperative assessment was done by a team that did not include the surgeon who did the denervation. The technique for selective knee denervation is described in detail. All 15 patients had at least 1 of the nerves to the knee selectively denervated (45 nerves in 15 patients). All patients reported subjective improvement in the immediate postoperative period. This improvement was maintained at a mean followup of 12 months (range, 6-16 months). Selective knee denervation is indicated in the management of intractable knee pain of neuroma origin after total knee arthroplasty.

Aged↗
PubMed1994

Total knee arthroplasty in diabetic patients. Comparison to a matched control group.

Between January 1980 and July 1989, 63 total knee arthroplasties were performed on 48 patients who had a clinical history of diabetes mellitus. Six patients died prior to completing the 2-year follow-up period and two patients (3 knees) were lost, leaving 53 knees in 40 patients available for review. The patients were considered as a total group, and were also divided into two subgroups: (1) insulin-dependent diabetes mellitus (IDDM) (9 knees) and (2) noninsulin-dependent diabetes mellitus (NIDDM) (44 knees). There were 10 men and 30 women in the series with an average age of 67. Patients were followed from 24 to 126 months (average, 54 months). The Porous Coated Anatomic total knee system (Howmedica, Rutherford, NJ) was used without cement in 30 knees and with cement in 23 knees. Diabetic patients were matched to a nondiabetic control group using a computer-generated selection process to match the following parameters: (1) age at surgery, (2) sex, (3) arthritic diagnosis, (4) length of follow-up period, (5) mode of fixation, and (6) preoperative deformity. Statistical analysis was performed using regression analysis and chi-square tests. In the diabetic group, there was an average clinical score of 85, with 43 knees (82%) rated excellent or good. Ten knees (18%) were rated fair, poor, or required revision (4 revisions, 7%). This was statistically different from the control group, which had an average clinical score of 92, with 51 knees (96%) rated excellent or good, 1 fair rating, and 1 revision (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Fractures of the ipsilateral femur after hip arthroplasty. A statistical analysis of outcome based on 487 patients.

A complete review of the literature revealed 487 patients in 26 published reports with ipsilateral femur fractures occurring about the femoral prosthetic stem. This review included general surveys, multicenter studies, and case reports. Based on these studies, the authors divided the fractures into six types: type 1, intertrochanteric; type 2, proximal femur; type 3, spanning the prosthesis tip; type 4, distal to the prosthesis tip; type 5, comminuted blowout; and type 6, supracondylar. Type 1-5 fractures were stratified into the following treatment groups: traction, casting and partial weight bearing, cerclage wiring, screw/plate fixation, long-stem revision with plus/minus supplementation fixation or bone-graft, and other less frequently reported techniques. A statistical analysis of each type of fracture in terms of the various treatments used and the clinical outcome was performed. The best results based on the literature would be cerclage wiring or long-stem revision for types 2, 3, and 5 fractures (P < .02). For type 4 fractures, traction and long-stem revisions were about equally successful (at 77 and 74%, respectively), and were both superior to screw/plate fixation or cerclage fixation (P < .01). Other factors, such as cemented versus cementless prostheses, stable versus unstable prostheses, overall medical condition of the patient, and other parameters, should be analyzed and considered when choosing a treatment course. Based on the authors' results, suggestions for the treatment of each fracture type are offered.

Femoral Fractures↗
PubMed1994

Management of ipsilateral supracondylar femur fractures following total knee arthroplasty.

A complete review of the literature revealed 195 fractures in 12 published studies of ipsilateral supracondylar femur fractures occurring about a total knee arthroplasty. This review included general surveys, multicenter studies, and case reports. Based on these studies, the authors divided the fractures into nonoperative and operative treatment groups. The fracture types were also subclassified into nondisplaced (Neer type 1) and displaced (Neer types 2 and 3). Statistical analysis of each type of fracture in terms of the various treatments and clinical outcome was performed. This study revealed satisfactory results in 83% of the patients with nondisplaced fractures that were treated without surgery. In contrast, 64% of all patients with displaced fractures that were treated with or without surgery had satisfactory outcomes. This difference is statistically significant (P < .05). Of the patients with displaced fractures, nonoperative versus operative results were not statistically significant (P < .9) (67% satisfactory vs 61%). A treatment algorithm is proposed based on the above data.

Femoral Fractures↗