Total knee arthroplasty in patients with pre-existing fracture deformity.

Pre-existing femoral or tibial extra-articular fracture deformity may adversely affect the results of total knee arthroplasty (TKA). This deformity can be addressed with asymmetrical intra-articular resection or with correctional osteotomy performed prior to or at the time of primary TKA. Careful preoperative planning obviates many potential problems that can occur at the time of surgery with correction of many complex deformities.

Extensor mechanism complications after total knee arthroplasty.

The patellofemoral joint is an important source of pain and complications following total knee arthroplasty. Anterior knee pain, patellar instability, fracture, rupture of the extensor mechanism, and a variety of miscellaneous problems affecting the patella can adversely affect the results of a total knee arthroplasty. Because patellofemoral complications after total knee arthroplasty often occur because of problems with patient selection, implant design, and surgical technique, it is important for orthopaedic surgeons treating patients with extensor mechanism complications after total knee arthroplasty to evaluate the entire knee replacement and base treatment on the etiology of the complication and not just the complication itself.

Factors affecting the durability of primary total knee prostheses.

BACKGROUND: Failure of total knee arthroplasty is problematic. The purpose of this study was to evaluate the factors that influence the durability of a primary total knee prosthesis. METHODS: A survivorship analysis of 11,606 primary total knee arthroplasties carried out between January 1, 1978, and December 31, 2000, was performed. An analysis of patient and implant-related factors affecting survivorship was done with use of a multivariate Cox model. RESULTS: The survivorship was 91% (95% confidence interval, 90% to 91%) at ten years (2943 knees), 84% (95% confidence interval, 82% to 86%) at fifteen years (595 knees), and 78% (95% confidence interval, 74% to 81%) at twenty years (104 knees) following the surgery. Prosthetic survivorship at ten years was 83% for patients fifty-five years of age or less compared with 94% for those older than seventy years of age (p < 0.0001), 90% for those with a diagnosis of osteoarthritis compared with 95% for those with inflammatory arthritis (p < 0.005), and 91% for those with retention of the posterior cruciate ligament compared with 76% for those with substitution of the posterior cruciate ligament (a posterior stabilized prosthesis) (p < 0.0001). Survivorship at ten years was 92% for nonmodular metal-backed tibial components, 90% for modular metal-backed tibial components, and 97% for all-polyethylene tibial components (p < 0.0001). Survivorship at ten years was 92% for prostheses fixed with cement compared with 61% for those fixed without cement (p < 0.0001). CONCLUSIONS: Significant risk factors for failure of total knee arthroplasty were the type of implant, age and gender of the patient, diagnosis, type of fixation, and design of the patellar component. In the ideal situation-treatment of a woman over the age of seventy years who has inflammatory arthritis with a nonmodular, metal-backed tibial component, cement fixation, an all-polyethylene patellar component, and retention of the posterior cruciate ligament-the ten-year survivorship of the prosthesis was estimated to be 98% (95% confidence interval, 97% to 99%).

Double level osteotomy of the knee: a method to retain joint-line obliquity. Clinical results.

BACKGROUND: Although general guidelines have been proposed for proximal tibial and supracondylar osteotomies, double level osteotomy provides the advantage of maintaining neutral joint-line obliquity in addition to correcting limb malalignment around the knee. The goal of this prospective study was to determine the outcome of double level osteotomy of the knee performed after analysis with computer-aided preoperative planning software in patients with varus malalignment. METHODS: Twenty-nine double level osteotomies of the knee were performed in twenty-four patients. The patients were followed for an average duration of 82.7 months (range, twenty-seven to 137 months). All knees had moderate-to-severe varus deformity and arthritis. The mean preoperative mechanical tibiofemoral angle was 193.9 degrees (that is, 13.9 degrees of varus). Preoperative and postoperative evaluations included clinical (scores according to the Knee Society system), radiographic, and computer-aided analysis of the mechanical status of the knee joint. Failure was defined as conversion of an osteotomy to a total knee arthroplasty or the presence of severe pain in a patient who declined arthroplasty. RESULTS: The mean clinical and functional scores according to the Knee Society system improved from 34 and 64 points, respectively, before the osteotomy to 90 (p < 0.0001) and 81 points (p = 0.079) at the time of the final follow-up examination. One patient was lost to follow-up. One of the twenty-nine knees was subsequently converted to total knee arthroplasty forty-nine months postoperatively. The cumulative rate of survival at 100 months was 96% (95% confidence interval, +4.5 to -8.7), with eight patients remaining at risk. CONCLUSIONS: Double osteotomy is a valuable procedure for patients with such a large varus deformity that appropriate realignment and load transfer to the unaffected compartment, together with an acceptable joint-line obliquity, cannot be achieved by a single osteotomy.

Extensor mechanism complications following total knee arthroplasty.

Patellofemoral complications are avoided by careful patient selection, proper implant design, and correct surgical technique. The patient with an extensor mechanism complication should be carefully evaluated for femoral and tibial component positioning, especially rotational alignment. Management of the extensor mechanism complication should be directed at its cause and may necessitate revision of the entire arthroplasty. Isolated revision of a patellar implant should only be performed once satisfactory alignment of the femoral and tibial components has been confirmed.

Upper tibia osteotomy: long term results - realignment analysis using OASIS computer software.

BACKGROUND: The normal values for axial alignment and joint line obliquity of the knee that indicate a successful valgus upper tibial osteotomy have not been established and reported in the literature. METHODS: To identify those parameters we prospectively followed 51 patients with 54 lateral closing wedge upper tibial osteotomies performed after preoperative and postoperative analysis of standardized hip-to-ankle radiographs with a software computer program (OASIS). RESULTS: Of the 54 knees, 18 (33.3%) underwent additional surgery. The average follow-up of the remaining 36 knees was 10 years (range 6.9-13.8 years). The cumulative osteotomy survival rate was 89% at 5 years and 76% at 10 years. Compared with patients whose postoperative femorotibial angle was 174 degrees -180 degrees , the patients whose postoperative femorotibial angle was <174 degrees or >180 degrees did worse with respect to osteotomy failure. Ten knees were at a decreased risk of failure. These knees had a postoperative femorotibial angle of 174 degrees -180 degrees , lateral joint line obliquity of <4 degrees , and a medial plateau force distribution of 40%-60%. The knees that met these criteria had 100% survival at 5 and 10 years, whereas the rest of the knees had survival rates of 86% and 70%, respectively. CONCLUSIONS: We believe that using these criteria during preoperative planning may improve the survival of upper tibial osteotomy provided a precise, reproducible surgical technique and rigid fixation can be performed.

Patellectomy after total knee arthroplasty.

UNLABELLED: We retrospectively reviewed nine patients who had condylar TKA and subsequently had a patellectomy between 1969 and 2003. One patient was lost to followup, but the remaining eight patients were followed up for an average of 49 months after patellectomy. All patellectomies were done after comminuted patellar fractures at an average of 21 months (range, 4-88 months) after the initial arthroplasty. Knee scores after the initial arthroplasty were 83 points (range, 69-97 points) and 49 points (range, 10-100 points) for pain and function, respectively. Knee scores after patellectomy were 81 (range, 20-97) and 28 (range, 0-80) for pain and function, respectively. The average range of motion before and after patellectomy was 0 degrees to 104 degrees and 2 degrees to 106 degrees , respectively. Four patients had mild extensor lags at final examination, but all were less than 10 degrees . Two patients were unable to use stairs. Two patients had complications consisting of quadriceps tendon rupture and secondary instability. Midterm results after patellectomy show knee scores for pain that are comparable to those after initial arthroplasties, but the function scores were not as good. Fifty percent of the patients had extensor lags but all were mild (< 10 degrees ). Patellectomy can provide pain relief after a patellar fracture after total knee arthroplasty but the functional results are frequently poor. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Treatment of the patella at reimplantation for septic total knee arthroplasty.

The results of treatment of the patella at the time of aseptic revision of a total knee arthroplasty (TKA) have been better with resurfacing of the patella than other modes of treatment such as leaving a bony shell. Treatment of the patella at the time of reimplantation of a TKA has not been addressed in prior studies. The ability to resurface the patella will be determined by the amount of bone remaining, integrity of the patella, vascularity, the location of the joint line, and soft tissue coverage for wound closure. The current review addresses the technique of patellar resurfacing and patellar bone defect treatment at the time of reimplantation of a TKA.

Collar versus collarless cemented HD-II femoral prostheses.

A randomized prospective study was done in 1982 to evaluate the effect of a collar on the cemented femoral component. During a 2-year period, 84 patients were enrolled to receive a collared (44 hips) or a collarless (40 hips) HD-II femoral component at the time of their primary total hip arthroplasty. Three patients were lost to followup, two patients were excluded because of randomization errors, six patients had good clinical results but refused followup, and 30 patients had died. The 43 surviving patients (collar 24, collarless 19) had radiographic and clinical followups at an average of 9.6 years (range, 61-143 months). Harris hip scores were similar, with an average of 89 in the collared group and 78 in the collarless group. There were no differences in the incidence or magnitude of pain between the patients receiving a collared or collarless femoral component. The Kaplan-Meier survivorship analysis predicted an overall survival rate free of revision of 86% at 10 years. There were no statistically significant differences in survival rates between the two groups.

Cemented long-stem revision total knee arthroplasty.

From 1981 to 1989, 38 cemented, posterior, stabilized, revision, total knee arthroplasties (TKAs) were performed at the authors' institution using the stemmed kinematic stabilizer prosthesis of a single design. The mean clinical follow-up after the index procedure was 10.1 years. The Knee Society pain score averaged 17 points before revision and improved to 51 points at last follow-up, and the function score averaged 48 points before revision and improved to 57 at last follow-up. Ten-year component survival free of revision or removal for any reason was 96.7%; 11-year component survival free of revision for aseptic loosening was 95.7%. Cemented stem fixation in revision TKA provides good clinical results with durable fixation at an average of 10 years' follow-up.

Revision total knee arthroplasty with cemented components and uncemented intramedullary stems.

Sixty-three failed total knee arthroplasties in 60 patients (27 females, 33 males; average age, 66 years) were treated consecutively with revision using cemented component fixation and an uncemented stem. Patients were followed for a mean of 5.75 years (range, 2-10 years); none were lost to follow-up. There were 12 (19%) re-revisions: 6 (10%) were revised for aseptic loosening, 4 (6%) for recurrent infection, and 2 (3%) for instability. Knee Society Pain Scores improved from 56 to 81, and function scores improved from 49 to 62 points. Latest radiographs in retained knees showed none with definite femoral loosening but 4 with tibial component loosening. Combining those revised for aseptic loosening and radiographic aseptic loosening, mechanical failure occurred in 10 patients (16%).

Reoperations after 3200 revision TKAs: rates, etiology, and lessons learned.

The purpose of this study was to evaluate the prevalence, etiology, and evolution with time of reoperations done after index revision total knee arthroplasties. After exclusion criteria were met, 1814 index knee revisions in 1627 patients were included in the final cohort with more than 50% of the revisions done for loosening and extensor mechanism problems and more than 80% of the revisions involving the femoral, tibial, or both components. Three hundred seventy-three knees subsequently have been reoperated on one or more times. The average time from index revision total knee arthroplasty to the first reoperation was 3.5 years (range, 1 day-19 years). Of the 1814 index revision total knee arthroplasties, 373 (20%) had 593 reoperations in 336 patients. The cumulative risks of first reoperation at 5, 10, and 15 years were 16.1% (95% CI, 14.2, 17.9), 26% (95% CI, 23.4, 28.6), and 31.4% (95% CI, 30.2, 39), respectively. There was no difference in risk to first reoperation when comparing the decades in which the index revisions were done (1970-1980, 1981-1990, and 1991-2000). There was a trend toward a higher cumulative risk of first time reoperations for deep infection, loosening, and instability in the last decade, but with the numbers available this was not statistically significant. The prevalence of reoperations in this large series of index revision total knee arthroplasties done for aseptic reasons was surprisingly high. Despite substantial improvements during the past 3 decades in component design, surgical technique, and prevention of infection, patients who have a revision total knee arthroplasty are at substantial risk of having one or more subsequent problems that result in a reoperation.