A comparison of primary and revision total knee arthroplasty using the kinematic stabilizer prosthesis

The first 121 arthroplasties (in 105 patients) in which the cemented kinematic-stabilizer total knee prosthesis was used for primary arthroplasty or surgical revision at the Mayo Clinic were reviewed. Sixty-six patients (seventy-nine arthroplasties) were followed for a mean of thirty-seven months. There were fifty-three revision and twenty-six primary arthroplasties. The average range of motion in both groups increased from 95 to 101 degrees. Although none of these patients could ascend stairs without support before the operation, thirty-two (51 per cent) could do so at the time of the final follow-up. The incidence of moderate or severe pain was reduced from 86 to 6 per cent. Moderate or severe ligamentous instability had been present in thirty-three knees (42 per cent) preoperatively, but only five knees had significant medial, lateral, anterior, or posterior instability at final follow-up. The Hospital for Special Surgery knee score increased from an average of 56 points to 83 points in all of the knees. At follow-up, the patients who had had primary arthroplasty had 92 per cent good or excellent results and the patients who had had surgical revision had 81 per cent good or excellent results (p less than 0.05). There was no significant difference in the results between the patients who had osteoarthritis and those who had rheumatoid arthritis. Over-all, 85 per cent of the results were good or excellent at final follow-up. Tibial radiolucent lines of one to two millimeters were observed in 29 per cent of the knees at follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)     

Total knee arthroplasty in young adults who have rheumatoid arthritis

At the Mayo Clinic, between 1978 and 1982, forty-four total knee arthroplasties were performed with cement in twenty-six adults who had rheumatoid arthritis. The age at operation ranged from nineteen to thirty-nine years old. The twenty-six patients were followed for two to eight years (average, five years). At the time of final follow-up, thirty-nine knees were free of pain and five were mildly painful during weight-bearing. The Hospital for Special Surgery knee score improved from a mean of 52 points preoperatively to 84 points postoperatively. There were twenty-four excellent, fourteen good, six fair, and no poor results. Radiographic analysis revealed an incomplete radiolucent line that was more than one millimeter in width adjacent to five tibial and four femoral components in eight knees (18 per cent). The positions of the components had not changed. Postoperatively, there was one transient peroneal palsy and two knees required patellar resurfacing. No revisions were performed for loosening of a prosthesis. We concluded that use of a cemented total knee prosthesis in a patient who has rheumatoid arthritis and is less than forty years old provides a satisfactory result and that the component will not loosen after an average of five years.     

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)     

Comparison of a hybrid with an uncemented total hip replacement. A retrospective matched-pair study

The efficacy of a type of uncemented total hip replacement was compared with that of a hybrid total hip replacement in which an uncemented acetabular and a cemented femoral component were used. Twenty-five patients who had had a hybrid total hip replacement were matched, by age, weight, sex, and diagnosis, with twenty-five patients who had had an uncemented total hip replacement. All of the operations were done by one surgeon, who used the same operative approach and the same regimen of postoperative rehabilitation. All of the patients were followed for at least two years. The mean postoperative hip score was 96 points for the hybrid group and 84 points for the cementless group (p less than 0.02). Twenty-four (96 per cent) of the patients who had a hybrid prosthesis reported no or only slight pain postoperatively. In the uncemented group, of the six patients (24 per cent) who reported mild to severe pain, five had pain in the thigh, a limp occurred more frequently, five femoral components had migrated, and four hips needed reoperation. The results with the hybrid replacement that had a cemented femoral component were superior to those with the uncemented femoral component over the relatively brief period for which these patients were followed.     

Range of motion of standard and high-flexion posterior stabilized total knee prostheses. A prospective, randomized study

BACKGROUND: The restoration of posterior femoral translation has been shown to be an important factor in enhancing knee flexion after total knee arthroplasty. The purpose of this study was to compare the ranges of motion associated with standard and high-flexion posterior stabilized total knee prostheses in patients managed with simultaneous bilateral total knee arthroplasty. METHODS: Fifty patients (mean age, sixty-eight years) received a standard fixed-bearing knee prosthesis in one knee and a high-flexion fixed-bearing knee prosthesis in the contralateral knee. Two patients were men, and forty-eight were women. At a mean of 2.1 years postoperatively, the patients were assessed clinically and radiographically with use of the knee-rating systems of the Knee Society and The Hospital for Special Surgery. RESULTS: The mean postoperative Hospital for Special Surgery knee score was 90 points for the knees treated with the standard fixed-bearing prosthesis and 89.4 points for those treated with the high-flexion prosthesis. At the time of the final follow-up, the knees with the standard prosthesis had a mean range of motion of 135.8 degrees (range, 105 degrees to 150 degrees ) and those with a high-flexion prosthesis had a mean range of motion of 138.6 degrees (range, 105 degrees to 150 degrees ) (p = 0.41). No knee had aseptic loosening, revision, or osteolysis. CONCLUSIONS: After a minimum duration of follow-up of two years, we found no significant differences between the groups with regard to range of motion or clinical and radiographic parameters, except for posterior femoral condylar offset.     

Total knee arthroplasty in patients </=50 years old

Thirty patients (30 knees) who underwent total knee arthroplasty at age 相似文献   

Results of unicompartmental knee arthroplasty at a minimum of ten years of follow-up

BACKGROUND: There is a renewed interest in unicompartmental knee arthroplasty. The present report describes the minimum ten-year results associated with a unicompartmental knee arthroplasty design that is in current use. METHODS: Sixty-two consecutive unicompartmental knee arthroplasties that were performed with cemented modular Miller-Galante implants in fifty-one patients were studied prospectively both clinically and radiographically. All patients had isolated unicompartmental disease without patellofemoral symptoms. No patient was lost to follow-up. Thirteen patients (thirteen knees) died after less than ten years of follow-up, leaving thirty-eight patients (forty-nine knees) with a minimum of ten years of follow-up. The average duration of follow-up was twelve years. RESULTS: The mean Hospital for Special Surgery knee score improved from 55 points preoperatively to 92 points at the time of the final follow-up. Thirty-nine knees (80%) had an excellent result, six (12%) had a good result, and four (8%) had a fair result. At the time of the final follow-up, thirty-nine knees (80%) had flexion to at least 120 degrees . Two patients (two knees) with well-fixed components underwent revision to total knee arthroplasty, at seven and eleven years, because of progression of patellofemoral arthritis. At the time of the final follow-up, no component was loose radiographically and there was no evidence of periprosthetic osteolysis. Radiographic evidence of progressive loss of joint space was observed in the opposite compartment of nine knees (18%) and in the patellofemoral space of seven knees (14%). Kaplan-Meier analysis revealed a survival rate of 98.0% +/- 2.0% at ten years and of 95.7% +/- 4.3% at thirteen years, with revision or radiographic loosening as the end point. The survival rate was 100% at thirteen years with aseptic loosening as the end point. CONCLUSIONS: After a minimum duration of follow-up of ten years, this cemented modular unicompartmental knee design was associated with excellent clinical and radiographic results. Although the ten-year survival rate was excellent, radiographic signs of progression of osteoarthritis in the other compartments continued at a slow rate. With appropriate indications and technique, this unicompartmental knee design can yield excellent results into the beginning of the second decade of use.     

Results after knee replacement with a posterior cruciate-substituting prosthesis

From 1979 to 1984, eighty patients (119 knees) were arbitrarily selected for treatment with knee arthroplasty in which a posterior cruciate-substituting replacement was used. The average age of the forty-nine women and thirty-one men was 66.9 years (range, twenty-two to eighty-four years). Sixty-one right and fifty-eight left knees were operated on, and bilateral replacement was performed in thirty-nine of the eighty patients. The diagnosis was osteoarthritis in fifty-eight patients (eighty-eight knees), rheumatoid arthritis in fourteen patients (twenty-two knees), osteonecrosis in three patients (four knees), and traumatic arthritis secondary to a fracture of the tibia or femur in five patients (five knees). The average preoperative score on The Hospital for Special Surgery knee-rating scale was 47.5 points, and the average range of motion preoperatively was 88 degrees (range, 30 to 140 degrees). Of the 119 knees, eighty-seven had a varus alignment (maximum, 35 degrees) before knee replacement. After follow-up of two to eight years, the average score on The Hospital for Special Surgery scale was 90 points, and the average range of motion was 107 degrees. Of the 119 knees, 83 per cent were rated as excellent; 15 per cent, as good; none, as fair; and 2 per cent, as poor. Radiolucencies of one millimeter were present in 76 per cent of the knees; of two millimeters, in 7 per cent; and of three millimeters, in 3 per cent. No statistically significant correlation between radiolucencies and the clinical result was found. The results in knees of patients who had rheumatoid arthritis were not as good as those in knees of patients who had other diagnoses (F = 11.44). Our experience suggested that the posterior cruciate-substituting design provides more motion than do the cruciate-sacrificing surface-replacement designs, with no deleterious effects. The rate of infection (1.6 per cent) after these procedures, which were carried out in a standard operating theater with vertical airflow, was equivalent to that in other published series in which rooms with laminar airflow were used. Patients who had a bilateral procedure did as well as those who had a unilateral replacement, but they required approximately 3.5 more units of blood.     

Cemented rotating-platform total knee replacement. A nine to twelve-year follow-up study

BACKGROUND: Although the LCS (low contact stress) rotating-platform mobile-bearing knee replacement has been used extensively, there have been few intermediate or long-term clinical and radiographic follow-up studies evaluating the device. The purpose of this study was to report the nine to twelve-year results of a consecutive series of patients who had a primary total knee replacement performed with this device. METHODS: Between November 1985 and November 1988, the senior author (R. C. J.) performed 119 consecutive total knee arthroplasties in eighty-six patients with LCS rotating-platform femoral and tibial components and a Townley all-polyethylene dome patellar component. All components were fixed with cement. The average age of the patients at the time of the operation was seventy years (range, thirty-seven to eighty-eight years). Fifty-two patients (seventy-six knees) were female, and thirty-four patients (forty-three knees) were male. The patients were evaluated with clinical knee ratings and radiographic analysis nine to twelve years following the knee replacement. RESULTS: At the time of the nine to twelve-year follow-up, sixty-four patients (eighty-six knees) were alive, eighteen patients (twenty-eight knees) had died, and four patients (five knees) had been lost to follow-up. Of the 114 knees in the eighty-two patients for whom the final outcome was known, none required a reoperation and none had a dislocation of the mobile-bearing prosthesis. For the forty-five patients (sixty-six knees) who returned for final clinical and radiographic follow-up examinations at nine to twelve years, the average clinical and functional Knee Society ratings were 30 points (range, 2 to 70 points) and 44 points (range, 0 to 80 points) preoperatively and 90 points (range, 63 to 102 points) and 75 points (range, 30 to 100 points) at the final follow-up evaluation. The average Hospital for Special Surgery knee rating was 57 points (range, 28 to 80 points) preoperatively and 84 points (range, 59 to 97 points) at the final follow-up evaluation. The average active range of knee flexion was from 0 degrees (range, 0 to 10 degrees) to 102 degrees (range, 15 to 120 degrees) at the final follow-up evaluation. Seven of the sixty-six knees were painful anteriorly. There was no periprosthetic osteolysis and no evidence of loosening on follow-up radiographs. CONCLUSIONS: After nine to twelve years of follow-up, the cemented LCS rotating-platform knee replacement was found to be performing well, with durable clinical and radiographic results.     

Survivorship analysis of the uncemented porous-coated anatomic knee replacement

Ninety-six patients who had a total of 108 replacements with an uncemented porous-coated anatomic knee prosthesis were followed for an average of sixty-four months (range, thirty-nine to ninety-three months). At the time of the most recent follow-up, twenty-one implants (19 per cent) had failed, all due to problems with the tibial component. A patellar component was not used, and no noteworthy patellar problems were encountered after the operation. There were no infections about the prostheses, and no femoral implant was revised. The most common cause of failure was collapse of the anteromedial part of the tibial plateau, which occurred in fourteen knees. The prosthesis loosened without collapse of bone in two knees, and five knees were revised because of gross wear of the polyethylene. When the time of failure was defined as the point at which revision of the prosthesis was recommended, the cumulative rate of survival was 84 per cent (95 per cent confidence interval, +/- 7 per cent) at five years and 77 +/- 10 per cent at six years. When the time of failure was defined as the point at which the knee replacement was actually done, the five-year rate of survival was the same. No significant differences were demonstrated between groups that were stratified by age, sex, weight, or primary diagnosis. We therefore do not recommend the use of an uncemented porous-coated anatomic knee replacement of the design that was evaluated in this study.     

The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears

BACKGROUND: The impact of a recurrent defect on the outcome after rotator cuff repair has been controversial. The purpose of this study was to evaluate the functional and anatomic results after arthroscopic repair of large and massive rotator cuff tears with use of ultrasound as an imaging modality to determine the postoperative integrity of the repair. METHODS: Eighteen patients who had complete arthroscopic repair of a tear measuring >2 cm in the transverse dimension were evaluated at a minimum of twelve months after surgery and again at two years after surgery. The evaluation consisted of a standardized history and physical examination as well as calculation of the preoperative and postoperative shoulder scores according to the system of the American Shoulder and Elbow Surgeons. The strength of both shoulders was quantitated postoperatively with use of a portable dynamometer. Ultrasound studies were performed with use of an established and validated protocol at a minimum of twelve months after surgery. RESULTS: Recurrent tears were seen in seventeen of the eighteen patients. Despite the absence of healing at twelve months after surgery, thirteen patients had an American Shoulder and Elbow Surgeons score of >/=90 points. Sixteen patients had an improvement in the functional outcome score, which increased from an average of 48.3 to 84.6 points. Sixteen patients had a decrease in pain, and twelve had no pain. Although eight patients had preoperative forward elevation to <95 degrees, all eighteen regained motion above shoulder level and had an average of 152 degrees of elevation. At the second evaluation, a minimum of twenty-four months after surgery, the average score, according to the system of the American Shoulder and Elbow Surgeons, had decreased to 79.9 points; only nine patients had a score of >/=90 points, and six patients had a score of /=80.     

Total knee arthroplasty in valgus knees

One hundred thirty-four total knee arthroplasties in 98 patients with a valgus alignment were analyzed. Knees with a preoperative alignment of 10 degrees or greater anatomic valgus were believed suitable for inclusion. The average follow-up period in these patients was 4.5 years (range, two to ten years). One hundred eighteen knees were implanted with a posterior stabilized prosthesis, eight knees with a constrained implant design, four knees with a total condylar prosthesis, and four knees with a cruciate-retaining design. All components in all knees were cemented. A lateral retinacular release was necessary in 76% of the arthroplasties secondary to intraoperative lateral subluxation of the patella. The ligamentous release for balancing these valgus-deformed knees was done from the femur. There were 95 knees (71%) rated as excellent, 27 knees (20%) as good, eight knees (6%) as fair, and four knees (3%) as poor. Postoperatively, 76% of the knees had a tibiofemoral alignment between 5 degrees and 9 degrees valgus with an overall average of 7 degrees valgus (range, 3 degrees varus to 15 degrees valgus). Total knee arthroplasty is a reliable and durable procedure in the treatment of valgus knee arthritis. However, valgus-deformed knees represent a greater challenge than their varus counterparts to the implant surgeon in terms of the intraoperative balancing required. This may be a function of the greater difficulty in achieving ligamentous equilibrium and the relative rarity of valgus-deformed knees.     

Prevention of venous thrombosis after total hip arthroplasty. Antithrombin III and low-dose heparin compared with dextran 40

The anticoagulant action of heparin is mediated through antithrombin III, and the postoperative decrease in the plasma concentration of antithrombin III may contribute to the relative ineffectiveness of prophylaxis with low-dose heparin in preventing venous thrombosis after total hip arthroplasty. We conducted a prospective, randomized trial to compare the effectiveness of a regimen of antithrombin III, given intravenously once daily, and low-dose heparin with a regimen of dextran 40, given intravenously, in preventing venographically documented venous thrombosis after total hip arthroplasty. The results demonstrated an incidence of venous thrombosis of 4.9 per cent in patients who received antithrombin III and heparin; this was significantly lower than the incidence (28.6 per cent) in patients who received dextran 40 (p less than 0.005). Venous thrombosis occurred only in patients who had total hip arthroplasty with a cemented prosthesis (fourteen of fifty-seven patients, or 24.6 per cent); none of the twenty-six patients in whom a non-cemented prosthesis was used had venous thrombosis (p less than 0.01). Of the patients in whom a cemented prosthesis had been inserted, the incidence of venous thrombosis was lower in those who were treated with antithrombin III and heparin (7.4 per cent) than in those who were treated with dextran 40 (40 per cent) (p less than 0.005). Postoperative levels of antithrombin III were maintained at more than 90 per cent of the baseline level in patients who received it; this was significantly higher than in patients who received dextran 40.(ABSTRACT TRUNCATED AT 250 WORDS)     

The press-fit Kinemax knee arthroplasty. High failure rate of non-cemented implants.

We report the results of 75 consecutive primary press-fit Kinemax arthroplasties with an average follow-up of 14 months (three to 28). We reviewed 26 cemented and 49 non-cemented tibial components implanted into 72 patients (30 men and 42 women, median age 70 years). At the latest follow-up the overall evaluation (Hospital for Special Surgery knee rating scale) for cemented cases was excellent in 54%, good in 42% and poor in 4%. No cemented prosthesis loosened. Of the non-cemented cases 55% were excellent, 23% good, and 2% fair. Ten tibial implants (20%) loosened and required revision. Residual pain marred the result in 24% of the non-cemented prostheses and in 4% of the cemented group. We do not recommend the press-fit, smooth-surfaced Kinemax prosthesis for non-cemented use.     

Use of a total condylar knee prosthesis for treatment of osteoarthritis and rheumatoid arthritis. Long-term results

Between May 1975 and December 1979, 113 patients had 153 arthroplasties using a total condylar knee prosthesis. Thirty patients (forty-two knees) died, and one (two knees) was lost to follow-up. Thirty-eight of these forty-four knees had been followed for more than two years, and none had had a revision. The remaining eighty-two patients (109 knees) were followed for an average of nine years (range, seven to 11.5 years). At the time of the latest examination, ten had had a revision for various reasons. For the ninety-nine knees that had the original prosthesis, the findings were compared with those of an evaluation that had been done four years postoperatively. The average over-all knee score was found to have decreased between the four-year and the latest follow-up evaluation, primarily because of a 7-point decrease in the score for function. The rate of infection was 0.6 per cent. The knees that had had patellar resurfacing had better over-all scores and better scores for pain than those that had not. This was particularly true in the patients who had osteoarthritis. The results of arthroplasty using a total condylar prosthesis appeared to be consistent and durable. Although there was a decrease in the quality of the functional result with increasing age, the patients reported consistent relief of pain.     

Total knee arthroplasty in neuropathic arthropathy

We describe the results of total knee arthroplasty (TKA) undertaken for severe, neurosyphilitic Charcot arthropathy in ten patients (19 knees). A cemented condylar, constrained prosthesis was implanted in all but two knees. The mean follow-up was 5.2 years (5 to 6). The mean knee score before operation was 36.5 points (30 to 42) which improved to 76 points (58 to 90) after operation as judged by the Hospital for Special Surgery score. At final follow-up three knees (16%) had aseptic loosening which required salvage by an arthrodesis, six (31%) were functioning poorly and ten (53%) were satisfactory. We conclude that although Charcot arthropathy is not an absolute contraindication to total knee replacement, there is a high incidence of serious complications.     

Surgical management of knee dislocations

BACKGROUND: The evaluation and management of knee dislocations remain variable and controversial. The purpose of this study was to describe our method of surgical treatment of knee dislocations with use of a standardized protocol and to report the clinical results. METHODS: Forty-seven consecutive patients presented with an occult (reduced) or grossly dislocated knee. Fourteen of these patients were not included in this series because of confounding variables: four had an open knee dislocation, five had vascular injury requiring repair, three were treated with external fixation, and two had associated injury. The remaining thirty-three patients underwent surgical treatment for the knee dislocation with our standard approach. Anatomical repair and/or replacement was performed with fresh-frozen allograft tissue. Thirty-one of the thirty-three patients returned for subjective and objective evaluation with use of four different knee rating scales at a minimum of twenty-four months after the operation. RESULTS: Nineteen of the thirty-one patients were treated acutely (less than three weeks after the injury) and twelve, chronically. The mean Lysholm score was 91 points for the acutely reconstructed knees and 80 points for the chronically reconstructed knees. The Knee Outcome Survey Activities of Daily Living scores averaged 91 points for the acutely reconstructed knees and 84 points for the chronically reconstructed knees. The Knee Outcome Survey Sports Activity scores averaged 89 points for the acutely reconstructed knees and 69 points for the chronically reconstructed knees. According to the Meyers ratings, twenty-three patients had an excellent or good score and eight had a fair or poor score. Sixteen of the nineteen acutely reconstructed knees and seven of the twelve chronically reconstructed knees were given an excellent or a good Meyers score. The average loss of extension was 1 degrees, and the average loss of flexion was 12 degrees. There was no difference in the range of motion between the acutely and chronically treated patients. Four acutely reconstructed knees required manipulation because of loss of flexion. Laxity tests demonstrated consistently improved stability in all patients, with more predictable results in the acutely treated patients. CONCLUSIONS: Surgical treatment of the knee dislocations in our series provided satisfactory subjective and objective outcomes at two to six years postoperatively. The patients who were treated acutely had higher subjective scores and better objective restoration of knee stability than did patients treated three weeks or more after the injury. Nearly all patients were able to perform daily activities with few problems. However, the ability of patients to return to high-demand sports and strenuous manual labor was less predictable.     

Osteotomy of the tibial tubercle during total knee replacement. A report of twenty-six cases

The cases of twenty-four patients who had twenty-six osteotomies of the tibial tubercle in conjunction with total knee replacement were analyzed with regard to complications and technical considerations. The patients were followed for a minimum of two years (average, three years and six months). Major complications related to the surgical technique occurred in 23 per cent of the knees and complications not related to the technique, in an additional 8 per cent. Rheumatoid arthritis and a history of at least one previous operation about the knee were predisposing factors for these complications.     

Primary repair of intraoperative disruption of the medical collateral ligament during total knee arthroplasty

BACKGROUND: Intraoperative disruption of the medial collateral ligament during total knee arthroplasty is an uncommon complication that is frequently treated by implanting a prosthesis with varus-valgus constraint. To our knowledge, no data have been published on primary repair or reattachment of the medial collateral ligament and implantation of a minimally constrained posterior-stabilized or cruciate-retaining prosthesis. This retrospective study evaluates the hypothesis that satisfactory clinical results, at a minimum of two years, can be achieved with immediate repair or reattachment of the medial collateral ligament and without a constrained total knee prosthesis. METHODS: Of 600 knees treated with primary total knee arthroplasty, sixteen (in fourteen patients) sustained either a midsubstance disruption of the medial collateral ligament or an avulsion of the ligament from bone during the procedure. Preoperatively, all patients had either neutral or varus alignment and an intact medial collateral ligament. Midsubstance tears were treated with direct primary repair, and avulsions of the ligament off the tibia or femur were treated with suture-anchor reattachment to bone. All patients wore a hinged knee brace, with no limit to the range of motion, for six weeks postoperatively. Clinical and radiographic data were gathered prospectively as part of a database that was ongoing throughout the period of study; the cohort of patients was assembled retrospectively by searching that database. RESULTS: No patients were lost to follow-up. The mean duration of follow-up was forty-five months (range, twenty-four to ninety-five months). The Hospital for Special Surgery knee scores increased from a mean of 47 points (poor) preoperatively to a mean of 93 points (excellent) at the time of final follow-up. On physical examination, no patient had a Hospital for Special Surgery score in the fair or poor range and all patients had regained normal stability in the coronal plane both at full extension and at 30 degrees of flexion. No patient required knee-bracing beyond the initial six-week postoperative period. The range of motion at the time of final follow-up averaged 108 degrees (range, 85 degrees to 125 degrees ), although one knee required manipulation under anesthesia to obtain a satisfactory range of motion. No arthroplasties required revision. Radiographic examination demonstrated appropriate limb alignment in all patients at the time of final follow-up. CONCLUSIONS: Intraoperative disruption of the medial collateral ligament can be treated with primary repair or reattachment of the ligament to bone and postoperative bracing with good results; this avoids the potential disadvantages associated with the use of varus-valgus constrained implants.     

Conversion of a fused knee with use of a posterior stabilized total knee prosthesis

BACKGROUND: Typically a hinged or condylar constrained prosthesis is recommended for total knee arthroplasty in a fused knee, to substitute for the absent or deficient collateral ligaments. The purpose of this study was to evaluate the stability and clinical results after the use of a posterior stabilized prosthesis in the conversion of a fused knee to a total knee arthroplasty. METHODS: Thirty-six patients (thirty-six knees) with a mean age of 39.2 years underwent conversion of a fused knee to a total knee arthroplasty with a posterior stabilized prosthesis. The mean duration of ankylosis had been 24.5 years. Clinical and radiographic evaluation was carried out preoperatively; at six weeks and three, six, and twelve months postoperatively; and annually thereafter. The mean duration of follow-up was 7.7 years. RESULTS: The mean preoperative Hospital for Special Surgery knee score of 60 points improved to 83.2 points at the final follow-up examination. Twenty-two knees were pain-free, and the remaining fourteen were mildly painful after prolonged walking. The mean amount of active flexion in the entire group was 77.7 degrees. The extension lag in the entire group averaged 12.5 degrees. Complications included necrosis of the skin edges in eighteen knees (50%), a rupture of the quadriceps tendon in two patients, and a pyogenic infection in two. No prosthesis required revision because of clinical or radiographic loosening. CONCLUSIONS: We believe that when the soft-tissue sleeves in a previously fused knee are carefully preserved intraoperatively, they can provide adequate stability after total knee arthroplasty with a posterior stabilized prosthesis. Therefore, we believe that use of that type of prosthesis is a reasonable alternative to the use of a more constrained implant in the treatment of this condition.