人工膝关节术后感染的诊断和二期翻修术

目的：对人工膝关节(TKA)术后感染接受二次翻修术的膝关节进行评估。方法：1996年1月～2002年1月实行人工膝关节置换术353膝，其中5个膝关节在术后出现感染，行二期翻修术即一期手术取出原假体，彻底清创，置入抗生素骨水泥间隙垫，术后使用6周以上的敏感抗生素，二期手术作假体翻修术。结果：平均随访2年，无1例翻修的膝关节发生感染或无菌性松动。最近一次随访时平均膝关节功能评分从翻修术前的0分增加到术后的58分(20～100分)，平均膝关节疼痛评分从术前的38分(24～50分)增加到术后的93分(87—100分)。结论：应该尽量采用二期翻修术处理TKA术后感染，以彻底的清除感染灶，使病人获得良好的功能。     

Functional results after revision of well-fixed components for stiffness after primary total knee arthroplasty

Between 1990 and 2001, 16 well-fixed, aseptic, primary total knee arthroplasties were revised in 15 patients for a diagnosis of stiffness. Patients were followed for a mean of 42 months (range, 2-6 years). Of 15 patients, 10 (66%) were satisfied with the results of the procedure. The mean Knee Society pain score improved from 28 to 65 points, and the mean functional score improved from 45 to 58 points. The mean arc of motion improved from 40 degrees preoperatively to 73 degrees postoperatively. Recurrent stiffness required additional intervention in 4 knees (3 patients, 25%). The results of revision of a well-fixed, stiff, primary total knee arthroplasty were mixed in our hands and provided only modest improvements in pain, function, and arc of motion. Key words: knee, arthroplasty, stiffness, revision, arthrofibrosis.     

Total knee arthroplasty in patients with a prior fracture of the tibial plateau

BACKGROUND: A fracture of the tibial plateau may predispose the knee to the development of posttraumatic arthritis. Malunion, intra-articular chondro-osseous defects, limb malalignment, retained internal fixation devices, and poor surrounding soft tissues may in turn compromise the outcome of total knee arthroplasty. The aim of our study was to evaluate the results of total knee arthroplasty in patients with a previous fracture of the tibial plateau. METHODS: The results of sixty-two condylar total knee arthroplasties performed with cement, from 1988 to 1999, in sixty-two patients with a previous fracture of the tibial plateau were reviewed. The fracture of the tibial plateau had been treated by open reduction and internal fixation in thirty-eight knees, external fixation in one knee, and nonoperatively in twenty-three knees. There were forty women and twenty-two men with an average age of sixty-three years at the time of the arthroplasty. Knee Society scores were recorded preoperatively and at the time of follow-up, at an average of 4.7 years, and complications were noted. No patient was lost to follow-up. RESULTS: The mean Knee Society scores improved significantly (p < 0.0001), from 43.9 points for pain and 52 points for function preoperatively to 82.9 and 84 points, respectively, at the time of the latest follow-up. There were thirteen reoperations, which included manipulation with the patient under anesthesia (five knees), wound revision (three knees), and component revision (five knees). There were six intraoperative complications (10%). A postoperative complication occurred in sixteen knees (26%). CONCLUSIONS: The vast majority of patients treated with total knee arthroplasty after a previous fracture of the tibial plateau have substantial improvement in function and relief of pain. However, these patients are at increased risk for perioperative complications, as evidenced by the high reoperation rate of 21% in this study.     

Stiffness after total knee arthroplasty. Prevalence of the complication and outcomes of revision

BACKGROUND: Stiffness is an uncommon but disabling problem after total knee arthroplasty. The prevalence of stiffness after knee replacement has not been well defined in the literature. In addition, the outcomes of revision surgery for a stiff knee following arthroplasty have not been evaluated in a large series of patients, to our knowledge. The purposes of this study were to define the prevalence of stiffness after primary total knee arthroplasty and to evaluate the efficacy of revision surgery for treatment of the stiffness. METHODS: We defined a stiff knee as one having a flexion contracture of >/=15 degrees and/or <75 degrees of flexion. Two separate groups were evaluated. First, the results of 1000 consecutive primary total knee replacements were reviewed to determine the prevalence of stiffness. Second, the results of fifty-six revisions performed because of stiffness, sometimes associated with pain or component loosening, after primary total knee arthroplasty were evaluated. RESULTS: The prevalence of stiffness was 1.3%, at an average of thirty-two months postoperatively. The patients with a stiff knee had had significantly less preoperative extension and flexion than did those without a stiff knee (p < 0.0001). There were no significant differences in age, gender, implant design, diagnosis, or the need for lateral release between the patients with and without stiffness. The second cohort, of knees revised because of stiffness, were followed for an average of forty-three months. The mean Knee Society score improved from 38.5 points preoperatively to 86.7 points at the time of follow-up; the mean Knee Society function score, from 40.0 to 58.4 points; and the mean Knee Society pain score, from 15.0 to 46.9 points. The mean flexion contracture decreased from 11.3 degrees to 3.2 degrees, the mean flexion improved from 65.8 degrees to 85.4 degrees, and the mean arc of motion improved from 54.6 degrees to 82.2 degrees. The arc of motion improved in 93% of the knees, and flexion increased in 80%. Extension improved in 63%, and it remained unchanged in 30%. CONCLUSIONS: The prevalence of stiffness in our series of 1000 primary knee arthroplasties was 1.3%. Revision surgery was a satisfactory treatment option for stiffness, as the Knee Society scores improved, the flexion contractures diminished, and 93% of the knees had an increased arc of motion. However, the results suggest that the benefits are modest.     

Results of MIS TKA at mean nine year follow-up

The first 103 consecutive minimally invasive total knee arthroplasties performed by a single surgeon were assessed to determine the clinical and radiographic outcomes at a mean of 9-year follow-up (range, 8 to 10 years). Patients who died before final follow-up were 10 (13 knees), leaving 90 knees in 69 patients for final review. Outcome was evaluated using Knee Society pain and functional scores. Survival with revision as an end point was 97.1%. Knee Society scores and range of motion improved significantly to a mean of 96 and 92 points and a mean of 115 degrees, respectively. There were five patients who required surgical intervention for unexplained pain with findings of retained cement and adhesions. Radiographic analysis did not reveal any progressive radiolucencies. These results suggest that excellent long-term outcomes can be achieved with minimally invasive total knee arthroplasty.     

Total knee arthroplasty in young patients with juvenile rheumatoid arthritis

BACKGROUND: Juvenile rheumatoid arthritis is a disabling and destructive condition that commonly affects the knee during childhood. Total knee arthroplasty occasionally may be necessary for the treatment of end-stage disabling arthritis of the knee in young patients. There is a paucity of available data on the results of total knee arthroplasty in adolescents. We report our experience with total knee arthroplasty in patients under the age of twenty years who had juvenile rheumatoid arthritis. MATERIALS AND METHODS: We reviewed the results of twenty-five consecutive total knee arthroplasties that had been performed at our institution between 1982 to 1997 in thirteen patients (mean age, seventeen years) with juvenile rheumatoid arthritis. The average duration of clinical follow-up was 10.7 years, and the average duration of radiographic follow-up was 6.5 years. RESULTS: The mean Knee Society pain score improved markedly from 27.6 to 88.3 points, and the mean Knee Society function score improved modestly from 14.8 to 39.2 points. There was a slight improvement in the range of motion. Symptomatic and progressive radiolucent lines were noted in two knees, one of which was revised. Two knees (one patient) required exchange of the polyethylene liner at thirteen years. There were four additional reoperations, including manipulation under general anesthesia (two knees in one patient), lysis of adhesions (one knee), and extensor mechanism realignment (one knee). CONCLUSIONS: Despite a substantial number of postoperative complications, total knee arthroplasty provided excellent relief of pain and improvement in function in this group of adolescent patients with juvenile rheumatoid arthritis.     

Total knee arthroplasty after varus osteotomy of the distal part of the femur

BACKGROUND: There is little information in the literature regarding the outcome of total knee arthroplasty following distal femoral varus osteotomy. The purpose of the present study was to evaluate the intermediate-term results of total knee arthroplasty following distal femoral varus osteotomy. METHODS: The study group consisted of nine consecutive patients (eleven knees) who had had a total knee arthroplasty following varus osteotomy of the distal part of the femur. The average age of the patients was forty-four years (range, fifteen to seventy years) at the time of the arthroplasty. The results were evaluated with use of the Knee Society score preoperatively and after a mean duration of follow-up of 5.1 years. Radiographs made preoperatively and at the time of follow-up were evaluated for alignment in the coronal plane. RESULTS: The mean Knee Society knee score was 35 points before the arthroplasty and 84 points after the arthroplasty. The mean Knee Society function score was 49 points before the arthroplasty and 68 points after the arthroplasty. The mean interval between the femoral osteotomy and the total knee replacement was fourteen years (range, two to thirty-two years). A constrained prosthesis was required in five of the eleven knees. Two knees had an excellent result, five had a good result, and four had a fair result. The mean arc of motion improved from 81.8 degrees to 105.9 degrees. The mean radiographic alignment was 3.6 degrees of valgus (range, 7 degrees of varus to 18 degrees of valgus) before the arthroplasty and 3.3 degrees of valgus (range, 1 degrees of valgus to 6 degrees of valgus) at the time of the latest follow-up. There were no infections or wound complications. CONCLUSION: Total knee arthroplasty following distal femoral varus osteotomy decreases pain and improves knee function, but the procedure is technically demanding and is associated with inferior results when compared with those of primary arthroplasty performed in a patient without a prior femoral osteotomy. In the present series, the use of an intramedullary femoral alignment guide increased the tendency to place the femoral component in relative varus angulation (that is, in <5 degrees of valgus). We recommend checking the alignment of the femoral component with an extramedullary guide in knees that have had a previous distal femoral varus osteotomy.     

Late outcome after implantation of the PFC modular knee system

AIM: The objective of the current, prospective study was the evaluation of long-term results after total knee arthroplasty with the PFC-Modular-knee system. METHOD: A total of 514 total knee arthroplasties were implanted between 1991 and 1994 in 248 female and 55 male patients. Their average age amounted to 62.4 years and 449 of them (87.4%) were re-investigated within the first half-year of 2000. Clinical and radiological data were evaluated according the recommendations of the American Knee Society. RESULTS: Late complications were observed in 6.5% of the cases. They consisted of prosthetic loosening (13 knees), patella problems (11 knees), instability (2 knees), periprosthetic fractures (2 knees), and one prosthesis fracture, 18 patients complained about a therapy-resistant, chronic pain syndrome. These findings lead to revision arthroplasty in 15 cases (3.3%). Preoperative American Knee Society Score values were on average 33, 35 an 17 points and improved to mean values of about 85, 79 and 5 points. Radiological signs of prosthetic loosening were observed in 12 cases (2.7%). CONCLUSION: Long-term results after total knee arthroplasty with the PFC-Modular-knee system showed a significant improvement in the patients' complaints and clinical findings at an average of 7.8 years postoperatively. Complication and revision rates of 6.5% and 3.3%, respectively, were low when compared with the international literature and--apart from this--decreased in the course of the observation time.     

Total knee replacement for posttraumatic degenerative arthritis of the knee

Althoughsignificantadvancehasbeenmadeinoperativetreatmentofkneefracturesoverthelasttwodecades,fracturesofthedistalfemurorproximaltibiastillmayleadtoposttraumatic arthritis.13Concomitantly,markedimprovementin totalkneearthroplasty(TKA)hasalsobeenmade durin…     

Midterm results of cemented Press Fit Condylar Sigma total knee arthroplasty system

PURPOSE: To evaluate the midterm results of 50 patients who underwent total knee replacement using Press Fit Condylar (PFC) Sigma system. METHODS: We retrospectively reviewed 87 consecutive cases (50 patients with 37 bilateral cases) of PFC Sigma total knee replacement performed between January 1998 and December 1999. Patients were evaluated clinically and radiographically by an independent observer. The American Knee Society Score, Oxford Knee Score, and Knee Society radiographic assessment were used to rate knee function and to determine the satisfaction level of each patient. RESULTS: The mean age of the patients at the time of operation was 65 years (range, 41-85 years). The mean follow-up period was 5.4 years (range, 4.5-6.4 years). 44 patients (79 knees) were available for follow-up, 3 patients (3 knees) were lost to follow-up, and 3 patients (5 knees) died of unrelated causes. At the final follow-up, the mean Oxford Knee Score was 22. Using the American Knee Society Score, 88% of the knees were rated excellent, 4% good, 2% fair, and 6% poor. Five knees required revision surgery, the indications being infection in 4 knees and aseptic loosening in one knee. The survival rate of the implants was 94% at 6 years. CONCLUSION: The PFC Sigma total knee arthroplasty system has demonstrated good midterm results at our institution.     

The modular segmental kinematic rotating hinge for nonneoplastic limb salvage

From January 1980 to July 1998, 25 patients (26 knees) were treated with an arthroplasty using a Modular Segmental Kinematic Rotating Hinge total knee prosthesis for nonneoplastic limb salvage. The indications included: nonunion of a periprosthetic femur fracture (11 knees), severe bone loss and ligamentous instability (eight knees), nonunion of a supracondylar femur fracture (four knees), acute periprosthetic fracture (one knee), fracture of a previous hinge (one knee), and prior resection arthroplasty (one knee). The average age of the patients was 72.3 years. Twenty-two arthroplasties were revisions. The average followup was 58.5 months. At the latest followup, knee extension averaged 2.4 degrees and flexion averaged 93.6 degrees. The Knee Society knee score improved from an average of 45.4 preoperatively to 75.5. Preoperatively, functional scores averaged 8.6 and improved to 25. Complications occurred in eight patients. The most common was deep infection (five patients). The use of the Modular Kinematic Rotating Hinge for nonneoplastic limb salvage represents a small proportion (0.14%) of all primary and revision knee arthroplasties done at our institution. The indications for the surgery are for a highly complex and small subset of patients. The patients in the current study gained significant improvement in overall range of motion, Knee Society knee scores, and functional scores when this prosthesis was used.     

Midterm results of mobile-bearing knee replacements

We examined the clinical and radiographic results of 93 patients affected by knee arthritis or osteonecrosis subjected to unilateral cementless mobile-bearing total knee arthroplasty with the LCS prothesis (Depuy/Johnson & Johnson). The mean follow-up was 9.5 years (range, 7–12 years). Clinical evaluation was performed using the Knee Society rating system, while radiographic evaluation was done according to the Knee Society roentgenographic system. At the latest follow-up, the mean knee score was 87 points: the functional score improved from 40 to 90. Radiolucent lines were small and not progressive. The implant survival at 12 years was 88%. Six knees (7%) required revision for implant-related problems. We conclude that the mobile-bearing prosthesis is a successful device even at long-term follow-up.     

Medial unicompartmental knee arthroplasty with the Miller-Galante prosthesis

BACKGROUND: Unicompartmental knee arthroplasty has become a popular treatment alternative for osteoarthritis that is confined to the medial part of the knee. Excellent intermediate-term results recently have been reported in association with the Miller-Galante unicompartmental implant. The purpose of the present study was to report on our longer-term experience with the Miller-Galante medial unicompartmental knee implant. METHODS: We evaluated the results of 113 medial unicompartmental knee arthroplasties that had been performed with use of the Miller-Galante implant in eighty-four patients between 1989 and 2000. The mean age of the patients at the time of surgery was sixty-eight years. Forty-five patients were men, and thirty-nine were women. Thirteen patients (sixteen knees) died at a mean of seven years after the index arthroplasty. No patient was lost to follow-up. The remaining seventy-one patients (ninety-seven knees) were followed for a mean of ten years and were evaluated with use of the Knee Society clinical and radiographic rating system. RESULTS: Eleven knees were revised at a mean of four years after the index procedure. The mean Knee Society knee and function scores for the sixty-one patients (eighty-six knees) who were living and who had not had a revision improved from 48 and 53 points preoperatively to 93 and 80 points at the time of the most recent evaluation. The five and ten-year rates of survival were 94% and 90%, respectively, with revision to tricompartmental knee arthroplasty as the end point and 93% and 86%, respectively, with revision or radiographic loosening as the end point. CONCLUSIONS: The Miller-Galante medial unicompartmental knee arthroplasty provided excellent pain relief and restoration of function in carefully selected patients and demonstrated durable implant survival at ten years.     

Revision total knee arthroplasty by impaction bone grafting

The presence of bone loss in a failed total knee arthroplasty can present a significant reconstructive challenge. Experience with the technique of using impacted morselized allograft with revision components having fixed stems is presented. Nineteen knees (21 patients) were reconstructed using impacted bone graft alone in 14 knees, bone graft plus methylmethacrylate in five knees (including one knee in which the replacement failed), and in three knees morselized bone graft was used in conjunction with structural bone allograft. Minimum followup ranged from 6 months to 62 months for the patients in the current series. These patients represent a relatively small, but growing portion of this surgeon's population of patients undergoing revision knee arthroplasty. Patients with large defects were selected for the study. Histologic specimens from the one failed knee arthroplasty revealed viable, incorporated bone graft. Excluding the replacement that failed, the average improvement in Knee Society combined knee and function scores was 87 points. The principles of revision and primary total joint arthroplasty are applied for achieving a stable implant. Specific to this technique, solid support of the implant-graft interface, graft-host bone interface, and the use of a tight, supportive stem is imperative. The author's experience provides additional support for the use of bone grafting techniques in patients with large bone defects who are undergoing revision total knee replacement.     

Extensor mechanism allografts in total knee arthroplasty.

Forty knees in 40 patients who had a chronic extensor mechanism disruption after knee arthroplasty underwent extensor mechanism allograft placement to restore extensor function. Thirteen knees were infected previously and 11 knees did not respond to previous attempts at direct extensor repair or reconstruction. Two patients died and two patients underwent above the knee amputation because of recurrent infection. The final group of 36 patients was studied for a mean followup of 3.6 years (range, 2-10 years). Clinical evaluations were performed using a modified Knee Society scoring system. The average range of motion in the entire group of patients was 1.4 degrees extension to 98 degrees flexion. The average extensor lag was 13 degrees in 15 of 36 patients. There were eight extensor allograft ruptures, which were treated by repeat extensor allograft placement. The average knee scores for function improved from 37 points preoperatively to 68 points postoperatively. Despite these initial ruptures, 34 of 36 patients had a successful clinical result. These results support the use of this technique for complete extensor mechanism loss after knee arthroplasty when direct repair is unfavorable.     

Total knee arthroplasty in patients with Paget's disease of bone at the knee

The purpose of this study was to identify the technical difficulties, complications, and long-term outcome of total knee arthroplasty in patients with Paget's disease. Twenty consecutive patients (21 knees) with Paget's disease at the knee who underwent primary total knee arthroplasty were retrospectively reviewed. All arthroplasties employed cemented condylar implants. Two patients died at less than 2 years and one was lost to follow-up; the remaining 17 (18 knees) were followed for an average of 9 years. Mean Knee Society scores for pain and function improved from 41 and 36 points preoperatively to 87 and 67 points, respectively, postoperatively. One patient underwent femoral revision for aseptic loosening at 10 years. None developed substantial heterotopic ossifications or deep infection. Total knee arthroplasty in patients with Paget's disease can provide good clinical results with low revision rate and good implant durability, despite technical challenges.     

The results of tibial tubercle osteotomy for revision total knee arthroplasty

Tibial tubercle osteotomy was used in the surgical exposure of 67 knees in 64 patients undergoing revision total knee arthroplasty. The clinical and radiographic results were reviewed retrospectively. The mean follow-up time was 30 months (range, 5-60 months). Knee Society scores (KSS) confirmed good or excellent results in 87% of the knees, and the mean KSS was 86. The procedure was particularly effective in 2-stage exchanges for infected total knee arthroplasty, in which infection was eradicated in 9 of 10 cases, with a mean KSS of 82. In this series, no patellofemoral complications, no component malalignments, and no avulsions of the patellar tendon occurred. Serious complications directly related to the tibial tubercle osteotomy occurred in 5 patients (7%).     

Press-fit condylar design total knee arthroplasty. Fourteen to seventeen-year follow-up

BACKGROUND: The Press-Fit Condylar total knee arthroplasty implant design has been used by many orthopaedic surgeons over the last twenty years. The design has survived with relatively minor modifications and remains a popular implant system today. The present study represents the fourteen to seventeen-year results for our patients who were described in our previous report on the eight to ten-year results. METHODS: The senior author performed 160 consecutive total knee arthroplasties with use of the Press-Fit Condylar cruciate-retaining device in 134 patients between 1986 and 1989. The mean age of the patients at the time of the index procedure was 70.5 years. Follow-up data were available for sixty-three of sixty-four surviving knees. Surviving patients were followed for a mean of 15.8 years. The knees were evaluated on the basis of Knee Society function and clinical scores, radiographs, and survivorship analysis. RESULTS: The mean Knee Society function score was 65, and the mean clinical score was 89. The overall survival rate of the knee was 91.5% with revision for any reason as the end point and 97.2% with aseptic loosening as the end point. The rate of revision of the tibial insert because of wear-related aseptic loosening was 2.5%. We found no relationship between revision and the shelf life or method of sterilization of the polyethylene insert. Radiolucent lines were present in 62% (twenty-one) of thirty-four knees; all radiolucent lines were nonprogressive. None of the implants were loose according to the criteria of the Knee Society. CONCLUSIONS: This long-term analysis indicates that the Press-Fit Condylar total knee implant is a successful implant system with excellent longevity.     

Distal Femoral Arthroplasty for the Treatment of Periprosthetic Fractures After Total Knee Arthroplasty

Periprosthetic fractures after total knee arthroplasty present substantial challenge if associated with poor bone stock, fracture comminution, and loose or damaged components. Revision total knee arthroplasty with distal femoral arthroplasty is often necessary in these injuries. We reviewed 20 patients (22 knees) with a mean age of 69.5 years who underwent revision with distal femoral arthroplasty fracture. Patients were followed for an average of 58.6 months. At the latest follow-up, the mean Knee Society knee and functional score were 82.8 and 40, and the Short Form 36 mean physical functioning and mental functioning scores were 55.8 and 65.6, respectively. There were 10 postoperative complications with 5 patients requiring additional surgery. Distal femoral arthroplasty seems to be a viable option for complex periprosthetic femoral fractures after total knee arthroplasty. However, considering the relatively high rate of complications, this procedure should be reserved for patients where alternative treatments are not possible.