Total knee arthroplasty in obese patients.

We examined 182 patients (257 knees) who had had a total knee arthroplasty two to five six years earlier. The patients were grouped into five weight classes. Eighteen patients (twenty-seven knees) were considered moderately obese and twelve patients (twenty-seven knees), severely obese. The results in all but four knees were rated excellent or good. One patient needed a revision procedure for late infection, and the result was rated poor. Three results were rated fair. There was no discernible difference in the over-all scores among the five weight groups. However, 30 per cent of the knees of the moderately and severely obese patients had patellofemoral symptoms, whereas the incidence was 14 per cent in the other groups (p less than 0.03). No clear-cut association was found between obesity and either thrombophlebitis or complications related to the wound.

Posterior stabilized prosthesis. Results after follow-up of nine to twelve years.

We reviewed, nine to twelve years postoperatively, the records on an original cohort of 289 arthroplasties (218 patients) in which a posterior stabilized knee prosthesis with an all-polyethylene tibial component had been inserted at The Hospital for Special Surgery. One hundred and eighty intact prostheses in 139 patients were available for this analysis. Fourteen knees in fourteen patients had had a revision procedure. Five of these fourteen patients had had a bilateral arthroplasty, but only one knee of each of the five patients had been revised. Forty-eight of the patients (sixty-six knees) had died less than nine years after the operation. Twenty-nine other knees (twenty-two patients) had been lost to follow-up before a nine-year evaluation could be performed. Considering all 194 knees (including the fourteen that had been revised), the result with the system of The Hospital for Special Surgery was excellent for 117 knees (61 per cent), good for fifty-one (26 per cent), fair for twelve (6 per cent), and poor for the fourteen knees (7 per cent) that had been revised. The 180 knees in which the prosthesis was intact were also rated with the new scoring system of The Knee Society: the average postoperative knee score was 92 points (range, 35 to 100 points), and the average score for function was 66 points (range, 0 to 100 points). Survivorship analysis showed that the average annual rate of failure was 0.4 per cent and that the over-all rate of success at thirteen years was 94 per cent.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone-block transfer of the medial head of the gastrocnemius for posterior cruciate insufficiency.

An operation is described in which the medial head of the gastrocnemius is firmly fixed by a cancellous screw, through an attached bone block, to the medial femoral condyle to serve as an intraarticular graft for the control of chronic posterior instability of the knee. This procedure was done in eight patients, with a follow-up of twenty-nine to forty-eight months. The delay from injury to reconstruction averaged forty-two months (range, five to eighty-four months). At follow-up, stability was improved in all of the eight patients and the result was rated as good or excellent in six of them. One failure was due to unrelieved pain and in another patient a second injury led to reoperation. Because minimum immobilization is necessary, the postoperative care with this procedure is simplified and the period of rehabilitation is shorter.

Patellar dislocation following total knee replacement.

The reported incidence of patellar problems after total knee replacement has ranged from 5 to 30 per cent. Patellar dislocation is infrequent but can cause disabling symptoms. Between January 1974 and May 1982, eleven patients (twelve knees) with symptomatic lateral dislocation of the patella after total knee replacement were treated at The Hospital for Special Surgery by realignment of the extensor mechanism. All of the patients were women. Their average age was sixty-two years and average weight, eighty-seven kilograms. The diagnosis was osteoarthritis in seven knees and rheumatoid arthritis in five. Most of the patients had had preoperative valgus deformity (average, 18 degrees). The cause of dislocation was trauma in three knees, incorrect tracking of the patella after replacement in six, and malrotation of the tibial component in three. Four different prosthetic designs had been used. The design of the implant did not appear to be a factor causing dislocation in this group. The patellar dislocation was treated by proximal realignment of the quadriceps in ten knees, lateral retinacular release alone in one, and revision of the tibial and femoral components combined with proximal realignment in one. After an average follow-up of thirty-four months (range, twenty-four to fifty-seven months), the results according to The Hospital for Special Surgery knee-rating scale were excellent in ten knees and good in two, and there had been no redislocations.

Proximal tibial osteotomy. A subjective outcome study.

We performed a retrospective study of the results of proximal tibial osteotomy in thirty-four men (thirty-seven knees) who had had unicompartmental osteoarthrosis of the knee. The average age of the patients at the time of the procedure was forty-nine years (range, twenty-eight to sixty years). The functional results were evaluated according to the system of Tegner and Lysholm, in which the level of participation in work and sports activities is graded on a scale from 0 points (complete disability) to 10 points (the ability to participate in competitive sports at the elite professional level). The average functional score was 5.4 points (range, 2 to 8 points) preoperatively and 4.8 points (range, 1 to 8 points) postoperatively. Postoperatively, many of the patients were able to participate in activities, such as running and jumping, that can lead to damage of the components of a total knee arthroplasty. Twenty-eight (82 per cent) of the thirty-four patients stated that the results had met their expectations and that they would have the operation again given the same situation.

High tibial osteotomy for varus gonarthrosis. A long-term follow-up study.

We evaluated the results in eighty-three patients (ninety-five knees) who had had a high tibial osteotomy for either unicompartmental osteoarthritis or osteonecrosis. The operations were performed between 1965 and 1976. The mean length of follow-up was 8.9 years (range, five to fifteen years). The early results were promising: at two years 97 per cent and at five years 85 per cent of the knees had either an excellent or a good result. At subsequent follow-up, however, only sixty knees (63 per cent) had an excellent or good result, and in the remainder recurrent pain had developed. Twenty-two knees (23 per cent) had been revised to a total knee arthroplasty because of pain. The alignment obtained by the osteotomy was not as important in determining the long-term result as we had previously believed. Although recurrent varus deformity was observed in more than one-quarter of the knees, it was not necessarily associated with an unsatisfactory result. The passage of time was the most important factor in determining the result, as only fifteen (37 per cent) of the knees that had been followed for more than nine years were pain-free. We now believe that total knee arthroplasty is a more suitable operation for patients who are more than sixty years old and that high tibial osteotomy should be reserved for patients who have a strenuous occupation or who wish to continue to participate in sports activities.

Technical considerations of total knee arthroplasty after proximal tibial osteotomy.

Forty-five total knee replacements in forty-one patients who had continued to have progressive osteoarthritis after a proximal tibial osteotomy were evaluated prospectively. There were 51 per cent excellent, 29 per cent good, 4 per cent fair, and 16 per cent poor results after a minimum follow-up of two years. The resection of tibial bone that was produced by the osteotomy could not be related causally to the fair or poor clinical results that were found after arthroplasty. Radiographic study, however, showed that 80 per cent of the knees had patella infera before the arthroplasty, which may contribute to altered biomechanics of the patellofemoral joint of the arthroplasty. The procedure for total knee replacement is made more difficult by the previous osteotomy, and a custom-made prosthesis may be required. The clinical results that were obtained in this series are similar to those for the revision total knee arthroplasties that have been done at this institution, but they were not as satisfactory as those that were obtained after primary total knee replacement. Our results should be considered when a surgeon compares the advantages and disadvantages of proximal tibial osteotomy with those of total knee arthroplasty for an older patient who has unicompartmental osteoarthritis of the knee.

Observations on patellar height after proximal tibial osteotomy.

Sixty-six knees (sixty patients) that had had a proximal tibial osteotomy were evaluated to determine if any alteration of the patellar height had occurred as a result of the operation. Eighty-nine per cent of the patellae, as measured by the Insall-Salvati index, and 76.3 per cent, as measured by the Blackburne-Peel index, were observed to be lowered as they appeared on the postoperative lateral radiograph. This was probably due to shortening of the patellar ligament after prolonged immobilization in a cast, interstitial scarring of the patellar ligament, and new-bone formation in the area of insertion of the patellar ligament. There was no correlation between the postoperative height of the patella and the need for subsequent revision to a total knee replacement.

Revision total knee arthroplasty for failed unicompartmental replacement.

The results in nineteen patients (twenty-one knees) who had a failed unicompartmental knee replacement followed by a revision total knee arthroplasty were evaluated. There were twelve excellent, four good, one fair, and two poor results. The interval between the unicompartmental replacement and the revision total knee arthroplasty ranged from eight months to eight years. At the time of the revision, a major osseous defect was found in sixteen knees (76 per cent). The duration of follow-up after the revision ranged from two to ten years. At the most recent follow-up examination, radiographs revealed at least one radiolucent line in thirteen knees (62 per cent). The technical difficulties associated with the revision operation are evidence that unicondylar arthroplasty is not a conservative procedure that allows a total knee arthroplasty to be done easily later. The results also do not support the argument that a revision performed after failure of a unicondylar arthroplasty is less technically demanding than one performed after a failed primary total knee arthroplasty.

Revision total knee arthroplasty with use of modular components with stems inserted without cement.

We reviewed the results of seventy-six revision total knee replacements, performed between 1980 and 1988 on the Knee Service at The Hospital for Special Surgery, in seventy-four patients. Sixty-five patients (sixty-seven knees; 88 percent) had a complete clinical examination and radiographic evaluation, and nine patients (nine knees; 12 percent) were only interviewed by telephone. Survivorship analysis was performed for all patients. The average duration of follow-up was three years and six months (range, two to nine years). Only patients who had had revision of the femoral component or the tibial component, or both, because of aseptic failure were included. The tibial component of all prostheses that were used for revision had a metal backing. Cement was placed on the cut surfaces in the metaphyseal region of the femur and tibia. Fluted diaphyseal intramedullary rods were used in all patients and were not cemented. Metal wedges and augments were used to fill osseous defects when necessary. The average preoperative knee score, according to the rating scale of The Hospital for Special Surgery, was 49 points (range, 0 to 62 points). Postoperatively, the knee score improved to an average of 76 points (range, 0 to 97 points). Of the sixty-seven knees that had complete follow-up, fifty-six (84 percent) had an excellent or good result and five (7 percent) had a fair or poor result. In six (8 percent) of the seventy-six knees, the prosthesis failed, necessitating another revision. Failure was defined as removal or a recommendation for removal of the implant.(ABSTRACT TRUNCATED AT 250 WORDS)

The posterior stabilized total knee prosthesis. Assessment of polyethylene damage and osteolysis after a ten-year-minimum follow-up.

The long-term results of use of the posterior stabilized total knee prosthesis were evaluated with regard to clinical performance, survival of the implant, polyethylene wear, osteolysis, and loosening. One hundred and twenty patients had 165 primary total knee arthroplasties, with insertion of a posterior stabilized total knee prosthesis with a metal-backed tibial component with cement, between March 1981 and March 1983. Thirty-seven patients (fifty-three knees) subsequently died, five patients (six knees) were lost to follow-up, three patients (three knees) refused evaluation, and one patient (two knees) was excluded because of severe medical debilitation. Thus, seventy-four patients (101 knees) were available for analysis. The mean age of the patients at the time of the operation was sixty-four years (range, twenty-two to eighty-one years). The mean duration of follow-up was ten years and eight months (range, ten years to eleven years and ten months). Preoperatively, the mean arc of motion was 94 degrees (range, 65 to 130 degrees), compared with 110 degrees (range, 90 to 145 degrees) at the latest follow-up examination. The mean knee score, according to the rating system of The Hospital for Special Surgery, was 51 points (range, 18 to 73 points) preoperatively, compared with 85 points (range, 0 to 100 points) at the latest follow-up examination. When the four knees that had a revision are excluded, the mean knee score, according to the rating system of the Knee Society, was 92 points (range, 67 to 100 points) and the mean functional score was 71 points (range, 0 to 100 points) at the latest follow-up examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary total knee arthroplasty after patellectomy.

The results of twenty-two consecutive primary total knee replacements, performed an average of nine years (range, one to twenty-three years) after a patellectomy in twenty-two patients, were reviewed retrospectively. The average duration of follow-up was seven years (range, three to fifteen years). The average age of the patients at the time of the arthroplasty was sixty-seven years (range, thirty-six to eighty-nine years). The average Hospital for Special Surgery knee score was 46 points (range, 22 to 74 points) preoperatively and 76 points (range, 45 to 97 points) postoperatively. Thirteen patients had an excellent or good result and seven had a fair or poor result; in two patients, the operation was considered a failure. Except for one patient who had myasthenia gravis, all patients could climb stairs in reciprocal manner. Four patients lacked 5 to 20 degrees of active extension compared with passive extension. With respect to the over-all results, there was no significant difference among the four types of prostheses that were used (p = 0.2). The patients who had received an Insall-Burstein posterior stabilized prosthesis had better scores for pain and function than did the patients who had received a total condylar I prosthesis (p = 0.005 and 0.01, respectively). There was a direct correlation between the knee score and the number of years that had elapsed since the patellectomy. The longer the interval between the patellectomy and the total knee replacement, the higher the postoperative knee score (r = 0.78, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of four models of total knee-replacement prostheses.

Twenty-nine knees with unicondylar, sixty-four with duocondylar, fifty with Guepar, and fifty with geometric prostheses were studied. The follow-up ranged from two to three and one-half years. The unicondylar prosthesis was used in the mildest cases and gave the least complications, but the quality of results was not superior to that achieved with the other prostheses. The duocondylar model was best suited for knees with rheumatoid arthritis and mild deformity. The geometric prosthesis was the best condylar prosthesis for osteoarthritis with moderate to severe deformity, but gave the worst results in knees with rheumatoid arthritis. The Guepar prosthesis was used in the worst knees and gave the best results, but it had the highest infection rate and was the most difficult to salvage. A radiolucency was observed in about 60 per cent of the condylar replacements around the tibial component and in 45 per cent of the Geupar replacements around the femoral component. The significance of this cannot yet be determined but it suggest that the fixation may not be ideal. In all types, residual pain was most frequently attributed to the patellar compartment. Patellectomy was not a solution.

Two-stage reimplantation for the salvage of infected total knee arthroplasty.

The results of eleven two-stage reimplantations to salvage eleven infected total knee arthroplasties in ten women (seven with osteoarthritis and three with rheumatoid arthritis) were evaluated after an average follow-up of thirty-four months. The staged procedures included removal of all of the components of the prosthesis and all cement, then six weeks of parenteral antibiotic therapy (monitored by maintaining serum bactericidal levels at a peak dilution of 1:8), and finally reimplantation with a total condylar-type prosthesis. All antibiotics were discontinued after reimplantation. At follow-up, no patient had had a recurrence of the original infection, but one had a hematogenous infection with a different organism secondary to an infected bunion. The results after reimplantation were rated excellent in five knees, good in four, and fair in two. Weakness of the extensor mechanism with an extension lag was the most frequent complication. We do not believe that antibiotic therapy alone is adequate for the management of an infection around a prosthesis. The method described appears to be effective but it is costly and time-consuming. The surgical procedures and medical management are technically difficult, often special equipment and a custom-made prosthesis are required, and there are no shortcuts.

Deep-vein thrombosis following total knee replacement. An analysis of six hundred and thirty-eight arthroplasties.

For this study on the incidence and prevention of deep-vein thrombosis, we examined the data on 517 patients with 638 total knee replacements. All of the patients had postoperative venograms and 475 had postoperative perfusion lung scans. We collected data on known risk factors, tourniquet time, knee deformity, postoperative rehabilitation, and methods of prophylaxis, and performed extensive statistical evaluation. Forty-nine patients inadvertently did not receive prophylaxis, and in forty-one (84 per cent) of them ipsilateral deep-vein thrombosis developed. The incidence of ipsilateral thrombosis was 57 per cent in the 468 patients who did receive some form of prophylaxis. Ipsilateral thrombosis in the popliteal veins or thigh was seen in 11 per cent of the patients with unilateral total knee replacement, and contralateral thrombosis was noted in 3 per cent. Bilateral total knee replacement was associated with a 58 per cent incidence of ipsilateral deep-vein thrombosis in the calf and a 14 per cent incidence in the thigh. Pulmonary embolism was diagnosed clinically in nine patients (1.7 per cent), but was suggested on perfusion lung scans in thirty-nine patients (7 per cent). Twelve patients (2.3 per cent) received formal anticoagulant therapy. In no patient was the pulmonary embolism fatal. No specific high-risk population was identified. While no one prophylactic regimen was proved to be more effective than another in our series, we think that prophylactic measures should be part of the management of patients undergoing total knee replacement.

Successive bilateral total knee replacement.

We studied the results of 304 posterior stabilized condylar knee arthroplasties, performed over a two and a half-year period, to compare unilateral, bilateral one-stage, and bilateral staged arthroplasty. The minimum length of clinical follow-up was two years. Using The Hospital for Special Surgery rating system, we found the clinical results to be identical for all three groups. The medical complications were similar in each group except that there was a higher incidence of thromboembolism and pulmonary embolism, as seen venographically, in the patients with staged procedures. We concluded that one-stage bilateral knee arthroplasty is preferable in a patient who requires replacement for severely arthritic knees.

Two-stage reimplantation for the salvage of total knee arthroplasty complicated by infection. Further follow-up and refinement of indications.

Thirty-eight total knee replacements (in thirty-five patients) that were complicated by infection were treated with a two-stage protocol for reimplantation. The clinical results in these knees (nine of which have been previously reported on) were evaluated at an average follow-up of four years (range, 2.5 to ten years). There was only one documented recurrence of infection with the original organism. Three patients in whom the immunological system was suppressed had a subsequent hematogenous infection with a different organism. According to the knee-rating system of The Hospital for Special Surgery, there were eleven excellent, thirteen good, six fair, and seven poor results. For one patient who had severe polyarticular rheumatoid arthritis, the result could not be rated. The results of this study suggested that the two-stage protocol for reimplantation, with a six-week interval of intravenous antibiotic therapy, is the procedure of choice for the treatment of an infection around a total knee arthroplasty. A patient who has polyarticular rheumatoid arthritis and in whom the immunological system is suppressed may not be an ideal candidate for the protocol. Gram-negative bacterial infection may be treated with this protocol, provided the organism is sensitive to relatively non-toxic antibiotic medication.

Pneumatic sequential-compression boots compared with aspirin prophylaxis of deep-vein thrombosis after total knee arthroplasty.

This prospective, randomized study was undertaken to compare the effectiveness of pneumatic sequential-compression boots with that of aspirin in preventing deep-vein thrombosis after total knee arthroplasty. Patients were randomly assigned to one of two prophylactic regimens: compression boots or aspirin. One hundred and nineteen patients completed the study. Seventy-two patients had unilateral arthroplasty and forty-seven, one-stage bilateral arthroplasty. In the unilateral group, the incidence of deep-vein thrombosis was 22 per cent for the patients who used compression boots compared with 47 per cent for those who received aspirin (p less than 0.03). In the bilateral group, the incidence of deep-vein thrombosis was 48 per cent for the patients who used compression boots compared with 68 per cent for those who received aspirin (p less than 0.20). The results confirm the effectiveness of compression boots in the treatment of patients who have had unilateral total knee arthroplasty. Despite the use of compression boots, however, patients who had bilateral arthroplasty were at greater risk for the development of deep-vein thrombosis.

Effects of epidural anesthesia on the incidence of deep-vein thrombosis after total knee arthroplasty.

Epidural anesthesia has been reported to reduce the prevalence of deep-vein thrombosis after total hip arthroplasty compared with the prevalence after general anesthesia. However, the effect of epidural anesthesia on the rate of thrombosis after total knee arthroplasty has not been reported previously, to our knowledge. A review was conducted of 705 total knee arthroplasties (541 patients) that had been performed by a single surgeon between September 1984 and December 1988. During this period, the operative technique, the protocol for rehabilitation, and the regimen for prophylaxis against thromboembolism did not change meaningfully. The patients received either epidural or general anesthesia. Preoperative and postoperative perfusion scans of the lungs and a venogram of the lower limb or limbs that had been operated on were done for all patients. For the 227 patients who had received epidural anesthesia, the over-all rate of deep-vein thrombosis was 48 per cent, which was significantly lower than the 64 per cent incidence in the 264 patients who had received general anesthesia (p less than 0.0001). The greatest reduction was in the occurrence of proximal thrombosis, which was identified in 9 per cent of the patients who had had general anesthesia but in only 4 per cent of those who had had epidural anesthesia (p less than 0.05). The use of epidural anesthesia reduced the incidence of proximal thrombosis after both unilateral and one-stage bilateral arthroplasty.

Total knee replacement in young, active patients. Long-term follow-up and functional outcome.

We reviewed our experience with total knee arthroplasties performed between 1977 and 1992 in patients who were fifty-five years old or less to determine the appropriate management for younger patients who have severe osteoarthrosis. One hundred and fourteen knee replacements were performed in eighty-eight patients who were an average of fifty-one years old (range, twenty-two to fifty-five years old). All of the operations were performed by one of the two senior ones of us (J. N. I. or W. N. S.) with the use of cementing techniques. A posterior stabilized, posterior cruciate-substituting design was used for all but one replacement, for which a semiconstrained total condylar prosthesis was used. Six knees (four patients) were lost to follow-up. Follow-up data for the remaining 108 knees (eighty-four patients) were used to perform the survivorship analysis. One hundred and three unrevised knees (eighty patients) were available for clinical evaluation with the scoring systems of The Hospital for Special Surgery and the Knee Society at an average of eight years (range, three to eighteen years) postoperatively; thirty-six knees were followed for more than ten years. In addition, the activity levels of the patients were assessed with the activity score of Tegner and Lysholm. Radiographs were examined for evidence of loosening of the component. At the latest follow-up examination, the average knee score according to the system of The Hospital for Special Surgery had improved from 55 points preoperatively to 92 points. According to the system of the Knee Society, the average knee score was 94 points and the average functional score was 89 points. The result for all 103 knees was good or excellent according to the knee scores of The Hospital for Special Surgery and the Knee Society. Ninety-seven knees (94 per cent) had good or excellent function according to the functional score of the Knee Society. The average activity score of Tegner and, Lysholm improved from 1.3 points (range, 0 to 4 points) preoperatively to 3.5 points (range, 1 to 6 points) at the latest follow-up examination. All but two patients had improvement in the activity score postoperatively, and nineteen (24 per cent) of the eighty patients had an activity score of at least 5 points, indicating regular participation in activities such as tennis, skiing, bicycling, or strenuous farm or construction work. Nine (9 per cent) of the 103 knees had non-progressive tibial radiolucent lines. Two patients had a revision because of late infection, and one patient had revision of a well fixed tibial component because of wear of the polyethylene. In addition, three patellar components were revised for loosening, and one spacer was exchanged to treat instability. With failure defined as revision of either the femoral or the tibial component, the over-all rate of survival was 94 per cent at eighteen years. When the three patellar revisions were included in the failures, the survival rate was 90 per cent at eighteen years. When the exchange of the spacer was also included in the failures, the survival rate was 87 per cent at eighteen years. We consider arthroplasty with cementing of a posterior stabilized total knee prosthesis to be effective operative treatment with durable results for osteoarthrosis in younger patients when other, less invasive measures have failed. Within the average eight-year follow-up interval of this study, polyethylene wear, osteolysis, and loosening of the conforming posterior cruciate-substituting prosthesis were not major problems for these younger, active patients, although it is possible that this observation could change with an even longer duration of follow-up.