Long-term deterioration of joint evaluation scores.

We investigated the long-term changes in the Harris Hip and Knee Society scores (HSS and KSS) to determine whether they result from overall functional decline rather than actual changes in the condition of the prosthesis. The HHS for 106 total hip arthroplasties with a minimum follow-up of ten years, no medical complications after operation and no evidence of radiological loosening, and the KSS for 264 total knee arthroplasties with a minimum follow-up of 12 years and no medical complications after operation or signs of radiographical loosening were evaluated. There were statistically significant drops in the functional scoring components of the joint evaluation systems despite no loosening of the prostheses or other significant medical complications. The HHS declined at an average of 0.67 points per year from between three and ten years after operation (p < 0.0001). Contributing to this were deterioration in gait and limp (p < 0.0004), the use of support aids (p < 0.0001), the distance walked (p < 0.0001) and the ability to climb stairs (p < 0.0455). The functional component of the KSS declined significantly at an average 0.88 points per year betwen the third and 12th years (p < 0.0001). There were significant declines in every component of the functional score including the distance walked (p < 0.0001), the ability to climb stairs (p < 0.0001) and the use of support aids (p < 0.0001). The knee score component of the KSS did not decline significantly (p < 0.9750). The combination of functional and pain scores within the HHS system leads to an inaccurate decline in the entire score. The decline of HHS and Knee Society functional scores in total joint arthroplasties, in the absence of implant-related problems, suggests that deterioration in the functional capacity of ageing patients is an important factor in longitudinal studies using these scoring systems.

Intra-operative findings in varus osteoarthritis of the knee. An analysis of pre-operative alignment in potential candidates for unicompartmental arthroplasty.

Interest in unicompartmental knee arthroplasty (UKA) for the treatment of medial compartment osteoarthritis has increased in recent years with apparent improvement in the long-term results. This is a result of improved surgical technique, patient selection, and implant design. In an effort further to improve patient selection we analysed the relationship between the pre-operative alignment of the knee and the anatomical findings at the time of surgery. We compared these findings with the indications for UKA. From 4021 total knee arthroplasties we compared intra-operative observations with the pre-operative clinical data in order to identify knees with isolated, medial, compartment changes, which would have been ideal candidates for UKA. We found that only 247 of the knees (6.1%) met anatomical qualifications for isolated, medial, unicompartmental osteoarthritis, and of these, only 168 (4.3%) met clinical standards ideal for UKA. Preoperative alignment showed a significant relationship with patterns of disease. Logistic regression revealed a relationship between pre-operative alignment and intraoperative findings resembling a Gaussian distribution. Patients with a pre-operative varus alignment of 7 degrees were slightly more likely to be selected for UKA. But the further the anatomical alignment in either direction varies from 7 degrees of varus, the more unlikely it is for the knee to exhibit a disease pattern of isolated, medial, unicompartmental osteoarthritis.

Short-term results of the M2a-taper metal-on-metal articulation.

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner group) were reported at mean follow-up intervals of 3.29 and 3.23 years. Radiographic evaluation revealed no evidence of early failure. No acetabular components have been revised or are pending revision. No statistically significant differences in the data were calculated between liner types except for the immediate postoperative (P=.0415) and minimum 2-year follow-up (P=.0341) angles of inclination. The M2a-taper metal-on-metal articulation may represent a viable alternative for THA in younger, higher demand patients.

Total knee arthroplasty with 4.4 mm of tibial polyethylene: 10-year followup.

A consecutive series of 387, one-piece, 8-mm tibial components were implanted in 313 patients. All tibial prostheses were manufactured with 4.4 mm of polyethylene directly molded to a 3.6 mm cobalt chrome metal baseplate. The average age of the patients at surgery was 70.6 years. From this group, a subset of 116 patients underwent bilateral total knee arthroplasties with an 8-mm tibial component on one side and at least a 10-mm thick tibial component (at least 6.4 mm of polyethylene) on the other side. The followup averaged 10.7 years. Postoperative knee and pain scores average 81.4 points and 47.2 points, respectively. No radiographic polyethylene wear or osteolytic lesions were identified. Tibial radiolucencies were observed in four knees. There were nine failures (2.3%). Three knees were revised for infection. Five knees were revised for metallosis secondary to failure of metal-backed patellas. No loose tibial components were identified. Defining failure as revision for any reason or loosening of any component, Kaplan-Meier survival rates at 5, 10, and 15 years were 98.7%, 95.4%, and 94.3%, respectively. There was no significant difference in clinical scores or survival rates between the knee components with thicker (at least 6.4 mm) or thinner (4.4 mm) polyethylene.

Long-term followup of anatomic graduated components posterior cruciate-retaining total knee replacement.

The purpose of the current study was to evaluate the authors' 15-year experience with the Anatomic Graduated Components total knee replacement. This is a report of the survivorship of 4583 Anatomic Graduated Component total knee arthroplasties. Kaplan-Meier survival analyses were performed with the end point defined as radiographic loosening, revision, or both. This end point was subdivided into the best case scenario in which it was assumed that all the patients lost to followup were doing well throughout the study and a worst case scenario in which it was assumed that all patients lost to followup had failed results at their last clinic visit. There were six (0.18%) femoral, 21 (0.46%) tibial, and 180 (4.2%) all-polyethylene patellar component failures secondary to aseptic loosening. All femoral components and 90% of the tibial components were revised; however, only 15 patellar components were revised. The clinical survival rate with revision of one or more of the components was 98.86% at 15 years. Despite having nearly flat-on-flat geometry and retaining the posterior cruciate ligament, which should increase the stresses in the polyethylene and at the bone-cement interface, this total knee replacement has proved to have minimal wear and excellent longevity with time. The authors think this is a result of the direct compression molded polyethylene articulation and the nonmodular configuration that incorporates metal backing on the tibial component and eliminates back-sided tibial component polyethylene wear.

The failure of all-polyethylene patellar components in total knee replacement.

The patellar component of total knee replacement is the most frequent source of nonseptic complications after total knee arthroplasty. The purpose of the current study was to review the radiographic factors associated with loosening of all-polyethylene patellar components. Four thousand five hundred eighty-three cases of Anatomic Graduated Components total knee replacements were performed at the authors' institution during the past 15 years. Radiographs were reviewed and loosening was defined as global radiolucency or component migration. Four thousand two hundred eighty-seven allpolyethylene patellar components were implanted. There were 180 (4.2%) loose all-polyethylene patellar components. The mean time to loosening was 2.6 years (+/- 1.75 years). Fifteen (0.3%) patellar components required revision. Five radiographic features were associated with failure. The incidence and mean time of appearance were recorded: (number; incidence; time) (1) Bone-cement radiolucency, n = 174, 96.7%, 1.4 years; (2) increased density, n = 118, 65.6%, 1.8 years; (3) trabecular collapse of the bone, n = 160, 88.9%, 2.3 years; (4) patella fracture and fragmentation, n = 133, 73.9%, 2.5 years; and (5) lateral subluxation of the residual patella bone, n = 146, 81.1%, 2.9 years. Lateral retinacular release was associated with an increased rate of patellar loosening. Loosening of the allpolyethylene patella component is an avascular process strongly associated with lateral retinacular release and for which the patient infrequently requires revision surgery.

A clinical comparison of the anterolateral and posterolateral approaches to the hip.

Patients who had anterolateral and posterolateral approaches in total hip replacement surgery were compared clinically for limp, dislocation, hospital stay, and discharge disposition. The only statistical difference was that the posterior approach had a statistically higher dislocation rate. Although the number of patients with limp was higher in the anterolateral group, the difference was not statistically different.

Does the preoperative radiographic degree of osteoarthritis correlate to results in primary total knee arthroplasty?

The preoperative radiographs of 1,888 patients undergoing 2,759 consecutive total knee arthroplasties (TKAs) performed for osteoarthritis (OA) were retrospectively reviewed to test the hypothesis that patients with less severe OA changes experience less pain relief and lower function scores after TKA. Age at surgery averaged 70.6 years, and follow-up averaged 2.5 years. Preoperatively, pain was independent of an arthritis grade, and this likewise was noted at > or =3 years after surgery. Patients with severe and mild radiographic changes of OA eventually experienced the same degree of function and pain relief after TKA.

The clinical significance of vacuum mixing bone cement.

This controlled study compared the strength and porosity of 48 polymethylmethacrylate cement-implant constructs prepared with open bowl versus vacuum mix technique. Forty-eight blast finished stainless steel rods of 13 mm diameter were implanted with centralizers into 17-mm inner diameter tubes that had been retrograde filled with polymethylmethacrylate cement. The eight cement preparations used were open bowl and vacuum mixed Simplex, Osteobond, Zimmer Dough Type, or Palacos R. Six replications of each condition were performed. The tubes were maintained at 37 degrees C. Each tube was cut transversely into five segments. The center three segments were used for data analysis: pushout strength, cycles to failure, and interface porosity analysis. Rod pushout data showed there was no significant difference between open bowl and vacuum mixed samples when all cement brands were combined. Mean sheer force for Palacos R vacuum mixed samples was greater than open bowl (634+/-47 versus 423+/-171), whereas the force for the Zimmer Dough Type cement open bowl was greater than that of the vacuum mixed samples (901+/-71 versus 705 +/-82). Cycles to failure data did not show significant differences when open bowl and vacuum mixed samples were compared when cements were analyzed individually or combined. Image analysis of cement-implant interfaces showed that vacuum mixing reduced void area significantly compared with open bowl mixing in the Palacos R and Osteobond preparations. Vacuum mixing does not appear to reduce cement prosthesis interface porosity or improve its mechanical properties in all cements.

Total knee replacement in patients with genu recurvatum.

Between June 1987 and March 1997, 57 total knee replacements were done in 53 patients with at least 5 degrees hyperextension deformity as measured on physical examination. The average recurvatum measured 11 degrees (range, 5 degrees-20 degrees). No cases of major ligamentous instability, neuromuscular disease, or inflammatory arthropathy were identified before surgery. Before surgery, Knee Society knee, function, and pain scores averaged 41 points, 41 points, and 13 points, respectively. A posterior cruciate-retaining prosthesis was implanted in all patients. The followup averaged 4.5 years (range, 3-10 years). Knee, function, and pain scores improved to 81 points, 78 points, and 43 points, respectively. Postoperative extension averaged 0 degrees (neutral) (range, 10 degrees hyperextension-10 degrees contracture). Only two (3.5%) knees had a hyperextension deformity after surgery. Both deformities measured 10 degrees and were in patients with a preoperative diagnosis of osteoarthritis. At final followup, no knee replacement was revised for any reason. In addition, only one case of a progressive radiolucent line greater than 1 mm (tibial Zone 7) was observed. Although the etiology of a hyperextension deformity should be elucidated before surgery, its presence does not preclude a well-functioning total knee replacement.

Total knee arthroplasty after high tibial osteotomy. A comparison study in patients who had bilateral total knee replacement.

BACKGROUND: The outcome of total knee replacement after high tibial osteotomy remains uncertain. We hypothesized that the results of total knee replacement with or without a previous high tibial osteotomy are similar. METHODS: The results of a consecutive series of thirty-nine bilateral total knee arthroplasties performed with cement at an average of 8.7 years after unilateral high tibial osteotomy were reviewed. There were twenty-seven men and twelve women. Preoperatively, the knee scores according to the system of the Knee Society were similar for all of the knees; however, valgus alignment and patella infera were more common in the knees with a previous high tibial osteotomy. Bilateral total knee replacement was staged in seven patients and was simultaneous in thirty-two patients. The results of the total knee arthroplasties were retrospectively reviewed with respect to the knee and function scores according to the system of the Knee Society, the radiographic findings, and the complications. RESULTS: Intraoperatively, no notable differences were identified in the number of medial, lateral, or lateral patellar releases required. However, less lateral tibial bone was resected in the group with a previous high tibial osteotomy (average, 3.3 millimeters) than in the group without a high tibial osteotomy (average, 7.5 millimeters). The average duration of follow-up was 7.5 years (range, three to sixteen years) in the group with a previous high tibial osteotomy and 6.8 years (range, two to ten years) in the group without a high tibial osteotomy. At the time of the final follow-up, the knee and function scores were similar for the two groups (89.0 and 81.0 points, respectively, for the group with a previous high tibial osteotomy, and 89.6 and 83.9 points, respectively, for the group without a high tibial osteotomy). Although more knees were free of pain in the group without a previous high tibial osteotomy (thirty-six) than in the group with a previous osteotomy (thirty-three), this difference was not found to be significant with the numbers available (p = 0.4810). Knee alignment and stability, femoral and tibial component alignment, and range of motion also were similar in both groups postoperatively. One allpolyethylene tibial component was revised in the high tibial osteotomy group. Two knees in each group required manipulation. There were no deep infections. CONCLUSIONS: While patients with a previous high tibial osteotomy may have important differences preoperatively, including valgus alignment, patella infera, and decreased bone stock in the proximal part of the tibia, the present study suggests that the clinical and radiographic results of primary total knee arthroplasty in knees with and without a previous high tibial osteotomy are not substantially different. In our relatively small group of patients, the previous high tibial osteotomy had no adverse effect on the outcome of the subsequent total knee replacement.

Windswept deformity in bilateral total knee arthroplasty.

Windswept deformity, when an individual has 1 knee in extreme varus alignment and the other in severe valgus alignment, is an unusual occurrence in patients presenting for bilateral total knee arthroplasty. This condition was evaluated in 22 patients to examine possible differences between knees in the same individual. Differences between the varus and valgus knees included alignment (P = .0001), as expected, and the position of the lateral joint line (P = .0161) preoperatively. No significant differences were observed between these 2 knee categories in any other comparison preoperatively or postoperatively. Total knee arthroplasty in patients with windswept deformity can be expected to be successful in both knees when attention is given to proper alignment and soft tissue balancing intraoperatively.

Is the preoperative radiograph useful in predicting the outcome of a total hip replacement?

The preoperative radiographs of 1015 patients undergoing 1163 total hip replacements for osteoarthritis were evaluated to determine if a relationship exists between the extent of osteoarthritis and the clinical results of a total hip replacement. Preoperative radiographs were graded with respect to the degree of cartilage space loss, direction of cartilage space loss (femoral head migration), and severity of osteophyte formation. Followup averaged 32.1 months (range, 6-93 months). Greater degrees of cartilage space loss correlated with lower hip scores preoperatively but were unrelated to preoperative pain. These patients had statistically less pain at 6 months and 1 year. Patients with superior cartilage space loss before surgery also had statistically less pain at 6 months. However, at 3 years and beyond, pain was independent of degree of preoperative cartilage space loss, osteophyte formation, or femoral head migration. In addition, hip scores at any followup were independent of the degree of osteoarthritis observed on the preoperative radiograph. These findings provide statistical support to the concept that greater degrees of joint space loss correlate with better relief of pain and less severe joint space loss correlates with less relief of pain within the first year after total hip replacement. At 3 years and beyond, hip and pain scores were independent of the degree of preoperative osteoarthritis.

Total knee arthroplasty after high tibial osteotomy.

Between 1980 and 1995, 95 consecutive total knee replacements were performed at an average of 10 years 4 months after high tibial osteotomy. The average age of the 82 patients was 66 years, with a preoperative diagnosis of osteoarthritis in 94 knees. One patient died 6 months after surgery. The followup of the remaining 81 patients (94 knees) averaged 8.6 years (range, 2-17 years). Knee Society knee score at final followup improved to an average of 87.6 points from a preoperative average of 38.1 points. No pain was present in 86.2% of knees, and 12.8% of knees had only mild or occasional pain. Tibial radiolucencies were identified in 12 (12.8%) knees at final followup, and in only four knees were radiolucent lines found about the lateral zones. Only one tibial component required revision 3 years after surgery. Although no preoperative factor was identified that predisposed to an inferior knee score, function score, or pain score, the severity of the preoperative flexion contracture and the number of previous surgeries did relate to diminished postoperative motion. However, an increased number of patellar radiolucencies were seen in the knees in which the lateral joint line was raised (referenced from the fibular head) a greater degree. The clinical results of total knee replacement after high tibial osteotomy appeared similar to those of primary total knee replacement. The previous high tibial osteotomy had no adverse effect on the eventual results of a cemented posterior cruciate retaining total knee replacement.

The effect of intraoperative intravenous fixed-dose heparin during total joint arthroplasty on the incidence of fatal pulmonary emboli.

All patients who underwent primary total knee arthroplasty (TKA), revision TKA, primary total hip arthroplasty (THA), and revision THA between January 1, 1990, and December 31, 1996, were retrospectively reviewed to determine the incidence of fatal pulmonary emboli. All TKA patients received 1,000 U of intravenous heparin sodium before the tourniquet was inflated and an additional 500 U of intravenous heparin sodium before the inflation of the second tourniquet during bilateral TKA. All THA patients received 1,000 U of intravenous heparin sodium at the time of the skin incision and 500 U of intravenous heparin sodium before preparation of the femoral canal. The overall incidence of fatal pulmonary emboli was extremely low (TKA, 0.096%; THA, 0.16%). With this regimen of intravenous intraoperative heparin, postoperative aspirin, thromboembolic disease hose, and early ambulation, there is no risk of postoperative bleeding, it is inexpensive, and there is no concern on how long to keep the patients on this regimen postoperatively. We recommend this regimen for the prevention of fatal pulmonary emboli after total joint arthroplasty.

Determining the necessity for routine pathologic examinations in uncomplicated total hip and total knee arthroplasties.

Total hip and total knee arthroplasties (n = 951) were retrospectively reviewed to determine the cost-effectiveness of routine pathologic examination of surgical specimens in primary total hip and total knee replacements. Discrepancies between the postoperative diagnosis and the final pathologic diagnoses were recorded. Of the 951 cases reviewed, 27 (2.8%) noted conflicting postoperative and pathologic diagnosis. In all cases, the discrepancy was between a postoperative diagnosis of osteoarthritis and pathologic diagnosis of avascular necrosis. No new cases of neoplasia or inflammatory arthropathy were noted based on the pathologic interpretation. Sixteen of these discrepancies (5.1%) and were noted in total hip arthroplasties, and 11 (1.7%) were noted in total knee arthroplasties. In no case was postoperative medical or surgical treatment altered. Based on this review, strong consideration should be given to the elimination of routine pathologic evaluation of surgical specimens during primary joint arthroplasty, leaving this pathologic evaluation optional, at the discretion of the orthopaedic surgeon, rather than mandatory.

The natural history of a posteriorly dislocated total hip replacement.

A retrospective review was conducted to delineate the natural history of the posteriorly dislocated total hip replacement. A total of 1,036 consecutive total hip replacements were performed between 1989 and 1992. Forty (3.9%) were known to have dislocated posteriorly. Twenty-four of these dislocations occurred after primary replacements, and 16 occurred after revision. Eighty-five percent of the dislocations occurred within 2 months and were reduced closed. No statistical differences were noted between these 2 groups with respect to height, weight, sex, age, and femoral and acetabular anteversion. Nonunion of the greater trochanter, modular femoral neck length, and operative approach appeared to affect hip stability. Twenty-three of the 40 dislocated hips (57.5%) redislocated. Sixteen of the 40 hips (40%) required reoperation for recurrent dislocation. Thirteen of the 16 revisions (81.3%) were successful. A dislocated total hip replacement that has been rendered stable does not preclude one from having a successful total hip replacement, and it does not appear to affect survivorship at intermediate follow-up.

Patellar complications (total knee arthroplasty). Effect of lateral release and thickness.

One thousand, one hundred forty-six Anatomic Graduated Component total knee arthroplasties performed between 1987 and 1989 were used to investigate the effects of patellar thickness alone or coupled with lateral retinacular release on initial patellar complications and maximal flexion. Lateral release was found not to be statistically significant regarding radiolucency, patellar prosthesis loosening, or an increase or decrease in flexion. However, total knee arthroplasties in which a lateral release was done, which either saved the superior lateral genicular artery or sacrificed the superior lateral genicular artery, were found to increase the incidence of initial patellar fractures and/or loosening (complications within 1 year) when compared with total knee arthroplasties in which a lateral release was not performed. There was no statistical difference in failure rates regarding fractures and/or loosening of the patella between lateral releases in which the superior lateral genicular artery was saved and the lateral releases in which the superior lateral genicular artery was sacrificed. A difference in postoperative patellar thickness compared with preoperative patellar thickness was found not to be significant to initial patellar fracture and/or loosening, patellar fracture alone, patellar loosening alone, radiolucency, the need for a lateral release, or to an increase or decrease in flexion. Lateral release and patellar thickness had no significant effect on patellar fracture and/or loosening.

Intra-articular morphine and/or bupivacaine after total knee replacement.

The postoperative analgesic effects of intra-articular injections of bupivacaine and/or morphine were examined prospectively in 437 patients who had total knee replacement for osteoarthritis. They were divided randomly into four groups. Group I received 10 mg of morphine (1 ml) and 9 ml of saline, group II received 10 ml of bupivacaine (2.5 mg/ml), group III received 10 ml of saline, and group IV received 10 mg of morphine (1 ml) and 9 ml of bupivacaine (2.5 mg/ml). All analgesics administered in the first 24 hours after operation were recorded. The patients rated their pain on the McGill-Melzack scale at 1, 6, 12 and 24 hours. No significant differences were found between any of the groups in the use of Demoral and/or Toradol in 24 hours, the length of stay in hospital or the pain rating at 1, 6, 12 or 24 hours. Patients in groups I and IV, whose injections included morphine, used significantly more morphine in the first 24 postoperative hours than did groups II or III.