Showing papers in "Journal of Arthroplasty in 1997"
TL;DR: Satisfaction with THA is a complex phenomenon, affected by expectations, outcome, and what patients know about the procedure from their community network, demonstrating that a better understanding of THA satisfaction will enable better future selection of patients and an additional dimension of outcome, both of which are important to patients and payers.
Abstract: Although there have been many studies focusing on the increasingly important assessment of patients' satisfaction, few studies have specifically addressed this tissue for total hip arthroplasty (THA). The goals of this study were to measure patients' satisfaction with THA and to evaluate the relationships of expectations and outcome to patients' satisfaction. A total of 180 patients were surveyed 2 to 3 years after THA about their experiences with THA. Patients cited 45 different expectations, which were grouped into five categories reflecting improvement in pain, walking, psychological state, essential activities, and nonessential activities. Overall, 89% of patients were satisfied with the results of surgery. Lower rates of satisfaction were found in patients who had a better preoperative condition (as measured by the surgeons with The Hospital for Special Surgery Hip Scale), in patients who expected improvement in nonessential activities, and in patients who reported worse postoperative condition (as measured by self-assessment with the Hip Rating Questionnaire and the Medical Outcomes Study Short-form General Health Survey). Patients were also asked how they came to THA. Nearly 50% of patients were first referred to an orthopaedist by family or friends or based on their own knowledge. Seventy-four percent either had subsequently referred others for THA or would have done so if they knew someone with hip pain. This study demonstrates that satisfaction with THA is a complex phenomenon, affected by expectations, outcome, and what patients know about the procedure from their community network. A better understanding of THA satisfaction will enable better future selection of patients and an additional dimension of outcome, both of which are important to patients and payers.
377 citations
TL;DR: The results indicate that both prosthetic component selection and surgical technique have a significant effect on prosthetic knee kinematics during functional activities.
Abstract: A fluoroscopic measurement technique has been used to provide detailed three-dimensional kinematic assessment of knee arthroplasty function during a step-up activity. Three groups of knee arthroplasty subjects with excellent clinical outcomes and similar ranges of motion were evaluated. Each group received different prosthetic components and surgical treatments of the posterior cruciate ligament (PCL). Group 1 had relatively flat articular surfaces with retention of the bony insertion of the PCL, group 2 had similar articular geometry but recessed the PCL without retaining the bony insertion, and group 3 had prostheses with greater sagittal conformity and post/cam substitution of the sacrificed PCL. Although none of the knees exhibited normal knee kinematics, the ranges of axial rotation and condylar translation for group 1 were similar to ranges previously reported for normal and anterior cruciate-deficient knees. Axial rotations and condylar translations decreased when the PCL was surgically recessed or substituted. The smallest kinematic ranges were observed in group 3. The results indicate that both prosthetic component selection and surgical technique have a significant effect on prosthetic knee kinematics during functional activities.
326 citations
TL;DR: Between 1985 and 1990, 108 consecutive Harris-Galante I (Zimmer, Warsaw, IN) total hip arthroplasties were performed by four surgeons at a single hospital, and a significantly greater volumetric wear rate was found in patients who were younger, those with a higher activity level, those who received a 32-mm-diameter femoral head, and those with vertical orientation of their acetabular component.
Abstract: Between 1985 and 1990, 108 consecutive Harris-Galante I (Zimmer, Warsaw, IN) total hip arthroplasties were performed by four surgeons at a single hospital. At the time of follow-up evaluation, 80 hips were available for review. The mean rate of linear wear was 0.15 mm/y, mean rate of three-dimensional femoral head displacement was 0.21 mm/y, and mean rate of volumetric wear was 121 mm3/y. Eight hips (10%) in this series had radiologic osteolysis around either the femoral or acetabular component. A significantly greater volumetric wear rate was found in patients who were younger, those with a higher activity level, those who received a 32-mm-diameter femoral head, and those with vertical orientation of their acetabular component. No relationship could be made with patient weight, gender, Harris hip score, or cup diameter.
261 citations
TL;DR: Nine (11%) of the 79 revision femoral prostheses showed massive subsidence, with another nine hips subsiding to a lesser degree, and further elucidation of the critical factors contributing to the initial stability of the biologic composite is required.
Abstract: The incidence of massive early subsidence (subsidence greater than 10 mm) following impaction grafting of the femur in revision surgery is reported. The first 79 consecutive revision total hip arthroplasties using morselized allograft, polymethyl methacrylate cement, and a double-tapered, polished, collarless stem were reviewed. Nine (11%) of the 79 revision femoral prostheses showed massive subsidence, with another nine hips subsiding to a lesser degree. Further elucidation of the critical factors contributing to the initial stability of the biologic composite is required.
232 citations
TL;DR: Sixty-one patients undergoing a two-stage revision of an infected hip using a prosthesis of antibiotic-loaded acrylic cement were followed for an average of 43 months, with a retrieval rate of 98% for those still living.
Abstract: Sixty-one patients undergoing a two-stage revision of an infected hip using a prosthesis of antibiotic-loaded acrylic cement were followed for an average of 43 months. Twelve patients were excluded (3 died, 6 had no proven infection, and 2 no second stage). Only 1 patient was lost to follow-up evaluation from those included, for a retrieval rate of 98% for those still living. Of the remaining 48 patients, 3 had further sepsis: Two became reinfected with different organisms and 1 with the same organism, for an infection eradication rate of 94%. The other 45 had no clinical, laboratory, or radiographic evidence of infection. Thirty-seven patients (80%) had a Harris hip score greater than 80 or an improvement of at least 30 points.
226 citations
TL;DR: This study shows that in selected circumstances, irrigation, debridement, and retention of the components can result in low morbidity with high success rates.
Abstract: The results of 24 infected total knee arthroplasties (22 patients) that were treated by irrigation, debridement, and retention of the prosthetic components were prospectively studied. Strict criteria were used for the selection of this method of treatment. Patients had to be less than 30 days after index arthroplasty (postsurgical group) or had to have less than 30 days of knee symptoms (hematogenous group). In addition, there had to be no radiographic signs of osteitis or evidence of a loose prosthetic component. Patients had one to three irrigation and debridement procedures depending on systemic signs, knee symptoms, or the results of knee aspirations. All of the immediate postsurgical infections (10 knees) and 10 of the 14 (71%) late hematogenously infected knees retained the prosthesis without further evidence of infection at the final follow-up visit at 48 months (range, 24-140 months). This study shows that in selected circumstances, irrigation, debridement, and retention of the components can result in low morbidity with high success rates.
204 citations
TL;DR: The plastic components of 280 retrieved unicondylar and total knee arthroplasties were studied and delamination was the principal were type and that the incidence of failure could accelerate considerably over follow-up periods beyond 10 years.
Abstract: The plastic components of 280 retrieved unicondylar and total knee arthroplasties were studied. Wear was visually scored using a relative ranked data method. Although wear on the components was highly variable, several conclusions could be drawn regarding the nature and causes. Wear was associated more with the medial than the lateral condyle. Delamination was the most severe type of wear and occurred in short ( 10 years)-term retrievals. In the short term, delamination wear was associated with hot pressing of the tibial plastic or with fracture of the tibial baseplate. For a single design, a significant difference in the amount of delamination on hot-pressed and non-hot-pressed tibial components was observed. In medium- and long-term retrieved specimens of the designs with moderately high conformity, delamination wear was associated with restriction of rotational movement of the femoral component or with abrupt changes in the radius of the tibial component. In flatter, less conforming designs, wear was associated with laxity, such that the polyethylene delaminated toward the edges of the tibial component. Wear attributed to cement abrasion or entrapment occurred on the more conforming designs. Delamination was associated with the presence of fusion defects in the polyethylene but could also occur in the absence of such defects. That delamination was the principal were type and that this is caused by a fatigue mechanism mean that the incidence of failure could accelerate considerably over follow-up periods beyond 10 years. Designs of moderate conformity without abrupt changes in radii may prolong the duration of plastic tibial components before serious delamination occurs.
204 citations
TL;DR: The 5- to 13-year follow-up data on 297 cementless revision arthroplasties with extensively coated components (Anatomic Medullary Locking femoral component, DePuy, Warsaw, IN) are reported and a basic classification of the femoral defects was developed.
Abstract: The 5- to 13-year follow-up data on 297 cementless revision arthroplasties with extensively coated components (Anatomic Medullary Locking femoral component, DePuy, Warsaw, IN) are reported. A basic classification of the femoral defects was developed. All patients were evaluated clinically and radiographically at a minimum of 60 months. Clinically, the average Postel-d'Aubigne score improved from 4.8 before to a 10.2 after surgery. Definite radiographic instability was noted in seven hips. Five patients were symptomatic and were revised. The mechanical failure rate was 2.4%. The overall complication rate was 5.7%, with a 2.6% dislocation rate. In the presence of bone loss in the proximal metaphyseal region of the femur, fixation of the femoral component is best achieved in the diaphyseal region of the femur using an extensively coated femoral component.
198 citations
TL;DR: Three hundred ten femurs in 300 patients suffering from primary hip osteoarthritis were analyzed by computed tomography scanning and several measurements were extracted, and the parameters essential to the characterization of the diverse femoral morphologies encountered were identified.
Abstract: In the field of uncemented hip arthroplasties, secondary biologic fixation of femoral implants depends directly on the quality of the primary stability. Metaphyseal filling and a good fit between the implant and the proximal femur improve initial stabilization and optimize the transmission of forces to the bone. Precise knowledge of the three-dimensional femoral shape is essential to the design and selection of adapted implants. Three hundred ten femurs in 300 patients suffering from primary hip osteoarthritis were analyzed by computed tomography scanning. After three-dimensional reconstruction, several measurements were extracted, and the parameters essential to the characterization of the diverse femoral morphologies encountered were identified. A new classification of the proximal femur is proposed. The consequences on the design and the preoperative selection of femoral implants are discussed.
191 citations
TL;DR: Nine patients have been identified over the past 15 years with persistent FLLI, and among the causes suggested are tightness of periarticular soft tissues with resultant pelvic obliquity and degenerative conditions of the spine with contracture.
Abstract: A consecutive series of 100 patients undergoing primary total hip arthroplasty were assessed for functional leg-length inequality (FLLI). In addition, the medical records of all patients treated for FLLI by the senior author (C.S.R.) in the past 15 years was reviewed. A questionnaire was distributed to the members of the Hip Society specifically to query the prevalence, etiology, and management of FLLI. Fourteen percent of patients were noted to have pelvic obliquity and FLLI.1 month after surgery. All had resolution of the symptoms by 6 months after surgery. Nine patients have been identified over the past 15 years with persistent FLLI. Among the causes suggested by respondents to the questionnaire are tightness of periarticular soft tissues with resultant pelvic obliquity and degenerative conditions of the spine with contracture. Methods of treatment and prevention are discussed.
154 citations
TL;DR: It is concluded that the midvastus muscle-splitting approach is an efficacious alternative to the medial parapatellar approach for primary total knee arthroplasties.
Abstract: This study presents a modification of the medial parapatellar surgical approach for total knee arthroplasty. This approach separates the vastus medialis muscle in the direction of its fibers beginning at the superior pole of the patella. One hundred eighteen consecutive total knee arthroplasty cases, performed by a single surgeon, were randomized prospectively to receive a medial parapatellar or midvastus muscle-splitting surgical approach. The frequency of lateral retinacular releases was recorded, patellar tilt and translation were measured, and quadriceps strength was tested. The midvastus muscle-splitting approach provided excellent exposure to all knees. Patellar stability and quadriceps strength were equivalent for the two approaches. It is concluded that the midvastus muscle-splitting approach is an efficacious alternative to the medial parapatellar approach for primary total knee arthroplasties.
TL;DR: The relationship between mortality rates and hospital patient volume for major orthopaedic surgery and diagnosis-related groups (DRGs) 209, 210, and 214 was examined, covering hip and knee arthroplasty, other hip and femur procedures, and spine procedures.
Abstract: This study examines the relationship between mortality rates and hospital patient volume for major orthopaedic surgery. All Medicare patients from fiscal years 1993 and 1994 in diagnosis-related groups (DRGs) 209, 210, and 214 were included, covering hip and knee arthroplasty, other hip and femur procedures, and spine procedures. Within DRG 209, five procedures were studied in more detail: total hip arthroplasty, partial hip arthroplasty, revision total hip arthroplasty, total knee arthroplasty, and revision total knee arthroplasty. Higher-volume hospitals had lower mortality rates, both in-house and in-house plus 30-day, for each of the DRGs studied and for each of the individual procedures within DRG 209. Age and sex were examined as potential causes of the differences in mortality rates, but no attempt was made to adjust for comorbidities or orthopaedic degree of difficulty. Results for 1995 are included in an appendix.
TL;DR: The results of this study suggest that the SF-36 health survey can capture additional important quality-of-life domains that are influenced by a THA and that these domains are influencedby the age and sex of the patient.
Abstract: The purpose of this study was to examine the relationship between the Harris Hip Score (HHS), a traditional method of patient assessment of a total hip arthroplasty (THA), and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), a commonly used health-related quality-of-life survey. One hundred forty patients returning for routine clinical follow-up evaluation of a primary THA were asked to fill out the SF-36 quality-of-life survey, as well as questions concerning their perceptions of their THA. The patient's surgeon assessed the THA with the traditional HHS. The correlations between the HHS and the SF-36 domains were highest in the physical component summary scores for male patients of all ages and female patients 65 years of age or older. The correlations were lower for the mental component summary scores of all patients, but particularly in female patients younger than 65. When the SF-36 scores were compared with age and sex-matched population norms, both age and sex were found to be important. Men younger than 65 had scores lower than norms in the physical function domains, but were comparable in the mental health domains. The older men had scores comparable to the norms in all domains. Female patients of all ages, however, had lower scores in the physical function domains. The greatest differences were noted in the female patients younger than 65. The HHS is commonly used to assess disease-specific pain and function in THA patients; however, the results of this study suggest that the SF-36 health survey can capture additional important quality-of-life domains that are influenced by a THA and that these domains are influenced by the age and sex of the patient. The combination of a disease-specific scoring system and a quality-of-life survey would allow a more global assessment of a THA in all patients. Studies evaluating the results of THAs should either assess the results of male and female patients separately when sample size is sufficiently large or use sex as a possible covariate in a multivariate analysis.
TL;DR: Patellofemoral contact stresses did not change significantly after total knee arthroplasty when the patella was not resurfaced, but they increased significantly after the patela was resurfaced with both the dome-shaped and the conforming components.
Abstract: Compressive contact stress between the patella and the anterior femur and between the quadriceps tendon and anterior femur was measured before and after total knee arthroplasty in 5 cadaver knee specimens using a digital electronic sensor. Contact stresses were measured in the normal knee and after total knee arthroplasty with an unresurfaced patella, a dome-shaped patella, and a conforming patella. Patellofemoral contact stresses did not change significantly after total knee arthroplasty when the patella was not resurfaced, but they increased significantly after the patella was resurfaced with both the dome-shaped and the conforming components. The conforming patella had the highest contact stresses because it tilted at flexion angles greater than 90 degrees and applied load to a small area on the superior portion of the patellar component. The conforming patella markedly decreased tendofemoral contact force because the thicker superior pole of the patella tented the quadriceps tendon at flexion angles greater than 120 degrees. This further increased patellofemoral contact force in deep knee flexion.
TL;DR: The results show that the true entry point is medial to the center of the notch, and rod placement error results in excessive valgus alignment, and the importance of correct use of the guide is demonstrated.
Abstract: Of the technical factors important in achieving a successful total knee arthroplasty, limb alignment has been demonstrated to be most influential in determining implant survival. Intramedullary femoral guide systems rely on placement of the intramedullary rod along the anatomic axis of the femur. In this article, the accuracy of the femoral intramedullary guide is investigated using radiographs and a mathematical model. The femoral anatomic axis was drawn on 40 consecutive, preoperative, 3-ft standing radiographs. Using a mathematical model, the potential angular error in the distal femoral cut from aberrant placement of the intramedullary rod was estimated. Calculated values correlated with measured values from plain radiographs and an intramedullary guide template. The anatomic axis was found to exit the distal femur at an average of 6.6 mm medial to the center of the femoral notch. Substantial malalignment error resulted from minor malposition of the intramedullary rod. Most books and diagrams demonstrating the use of intramedullary guides indicate that the entry point is at the center of the femoral notch. These results show that the true entry point is medial to the center of the notch, and rod placement error results in excessive valgus alignment. Preoperative drawing of the anatomic axis on a 3-ft or 18-inch anteroposterior radiograph is recommended. The results both demonstrate the importance of correct use of the guide and heighten cognizance among surgeons performing total knee arthroplasty as to the limitations of the intramedullary guides.
TL;DR: The wear observed on a retrieved hip implant obtained postmortem from a low demand patient 1 year after total hip arthroplasty indicates that rigorous testing and evaluation of titanium nitride coating technology should be conducted prior to widespread use on total joint implants.
Abstract: There is increasing interest in using surface modification technology to improve the wear properties of titanium alloy and limit articular surface wear of metal and polyethylene components. This report details the in vivo wear performance of titanium nitride coating on a retrieved hip implant obtained postmortem from a low demand patient 1 year after total hip arthroplasty. Analysis of the well-functioning implant revealed that wear debris can originate from a titanium nitride coated femoral head, as delaminated surface asperities, and manifest as adhesive wear on the articular surface. The wear observed on this implant indicates that rigorous testing and evaluation of titanium nitride coating technology should be conducted prior to widespread use on total joint implants.
TL;DR: The results suggest that drains may not be needed following total hip arthroplasty, and the more common serous wound discharge may be of some concern when drains are not used following total knee arthroPLasty.
Abstract: The efficacy of closed suction drains following joint arthroplasty operations was prospectively evaluated in a randomized manner. All 88 patients allotted to primary knee or hip arthroplasty operations during a 6-month period were included in the study. Drains were used in 32 of 58 patients following total knee arthroplasty and in 18 of 30 total hip arthroplasties. No statistical difference was found in the hemoglobin levels measured following surgery and in the number of patients requiring blood transfusions between the two groups after total hip arthroplasty (P = .06). The power of the test to detect a difference of 2 g% in hemoglobin levels is 94%. Two patients from each group had a transient serous discharge for 3 to 4 days following surgery and none had wound infections. Significantly more blood transfusions were needed in patients with drains following total knee arthroplasty compared with patients without drains (0.7 unit per patient versus 0.2 unit per patient, P = .005) to maintain the same hemoglobin blood levels. Patients with no drains had significantly more transient sterile serous wound discharge than patients with drains (38.4% vs 12.5%, P = .02). Superficial wound infection necessitating antimicrobial medication developed in one patient with drains and in no patients in the other group. These results suggest that drains may not be needed following total hip arthroplasty. The more common serous wound discharge may be of some concern when drains are not used following total knee arthroplasty.
TL;DR: The results of 57 revision total knee arthroplasties performed for aseptic failure between 1984 and 1992 with a cemented posterior-stabilized or constrained condylar prosthesis were reviewed at follow-up examinations at a minimum of 36 and an average of 62 months.
Abstract: The results of 57 revision total knee arthroplasties performed for aseptic failure between 1984 and 1992 with a cemented posterior-stabilized or constrained condylar prosthesis were reviewed at follow-up examinations at a minimum of 36 and an average of 62 months (range, 36-120 months). The reason for revision was aseptic loosening of 1 or both components in 32 knees (56%), instability in 16 knees (28%), polyethylene wear and osteolysis in 4 knees (7%), supracondylar femur fracture in 2 knees (4%), and a failed allograft, pain, and arthrofibrosis in 1 knee each (5% total). The average age of the patients at the time of the revision was 74 years (range, 38-90), and the original diagnosis for the majority of patients was osteoarthritis (74%). All of the revision prostheses were cemented posterior stabilized or constrained condylar-type implants. Bone deficiencies were grafted with cancellous allograft in contained defects and cortical allograft in noncontained defects. Five knees were reconstructed with allograft-prosthesis composites. The average modified Hospital for Special Surgery knee score improved from 49 to 82 (100 points possible) at final follow-up evaluation (P .05).
TL;DR: Subtrochanteric osteotomy in total hip arthroplasty for developmental dislocation of the hip allows for acetabular exposure and diaphyseal shortening while facilitating femoral derotation, and some of the potential complications of greater trochanterics osteotomy may be avoided.
Abstract: A surgical technique, which uses a transverse osteotomy, for subtrochanteric femoral shortening and derotation in total hip arthroplasty for high-riding developmental dislocation of the hip is described. Anteversion is set by rotating the osteotomy fragments, and torsional stability is augmented with allograft struts and cables when indicated. Eight patients with 9 total hip arthroplasties were followed for an average of 43 months (range, 24-84 months). Good to excellent results were obtained in 87% of patients (7 of 8). Eight of 9 osteotomies (89%) demonstrated radiographic evidence of healing at an average of 5 months. One patient had an asymptomatic nonunion of the osteotomy site but still had a good overall clinical result. Another patient suffered fatigue failure of a distally ingrown porous device, which necessitated revision total hip arthroplasty 18 months after surgery. Subtrochanteric osteotomy in total hip arthroplasty for developmental dislocation of the hip allows for acetabular exposure and diaphyseal shortening while facilitating femoral derotation. Furthermore, proximal femoral bone stock is maintained and some of the potential complications of greater trochanteric osteotomy may be avoided.
TL;DR: The postoperative radiographs of 35 patients who underwent impaction allografting of the proximal femur were reviewed and it was concluded that the surgical technique requires modification to ensure a more consistent cement mantle and clinical result.
Abstract: The postoperative radiographs of 35 patients who underwent impaction allografting of the proximal femur were reviewed. Of Gruen zones that could be clearly visualized, 39.9% contained areas where cement was absent. Even when an adequate mantle was present, cement voids were commonly seen. These cement mantle deficiencies were confirmed in a series of cadaveric impaction allografting procedures. They appear to be a consequence, at least in part, of an inadequate differential between trial and actual component sizes. Additionally, 4 patients were identified with significant component migration secondary to radiographically visible cement mantle fractures within the first 6 months of surgery. It is concluded that the surgical technique requires modification to ensure a more consistent cement mantle and clinical result.
TL;DR: Results were suggestive of a modest short-term reduction in pain scores in the morphine and bupivacaine treatment groups compared with placebo; however, results were statistically significant only at 4 hours because of the great variability in the pain score data.
Abstract: The purpose of this study was to determine if intra-articular injection of morphine or bupivacaine significantly decreased postoperative pain as well as the use of intravenous narcotics for pain relief in patients undergoing total knee arthroplasty (TKA). In a prospective, double-blind, randomized fashion, 105 patients undergoing TKA were divided into the following 4 groups defined by the intra-articular injection they received: group 1 (n = 27) received saline solution, group 2 (n = 26) received morphine sulfate (5 mg), group 3 (n = 24) received bupivacaine (50 mg), and group 4 (n = 28) received a combination of morphine sulfate and bupivacaine. The injections were administered immediately after wound closure by the Hemovac drainage tubing that remained clamped for 45 minutes after surgery to allow for absorption. Before surgery and at 2, 4, 6, 24, and 48 hours after surgery, pain intensity was recorded using a visual analog scale. Postoperative supplemental intravenous morphine and/or meperidine was administered via a patient-controlled analgesia device, and 24-hour drug usage was tabulated. Results were suggestive of a modest short-term reduction in pain scores in the morphine and bupivacaine treatment groups compared with placebo (saline); however, results were statistically significant only at 4 hours because of the great variability in the pain score data. The total amount of postoperative pain medication used in the first 24 hours after surgery was not statistically significant between the 4 treatment groups. Thus, the results put into question the benefit of postoperative intra-articular administration of morphine or bupivacaine in patients undergoing TKA.
TL;DR: For total knee arthroplasty, using the tourniquet at a pressure of 100 mmHg above the systolic blood pressure is recommended to provide a bloodless field and will result in a less unpleasant postoperative period.
Abstract: Thigh pain following tourniquet application is a common patient complaint in the early postoperative period following total knee arthroplasty. Postoperative thigh pain was evaluated in 28 consecutive simultaneous bilateral total knee arthroplasty patients between April 1996 and October 1996. A prospective, double-blind, randomized clinical trial was performed. Tourniquet pressure of 350 mmHg was used on 1 thigh (thigh 1) and 100 mmHg plus systolic blood pressure on the other (thigh 2). A scale of pain (no pain, mild, moderate, or severe) was applied on the first, second, and third days, as well as 2 and 6 weeks after surgery. There were 16 men and 12 women with a mean age of 72 years (range, 55-85 years). The mean tourniquet time was similar in both groups (thigh 1 = 23 minutes, thigh 2 = 22 minutes). The mean tourniquet pressure in thigh 2 was 230 mmHg (range, 212-260 mmHg). There was a statistically significant difference in thigh pain on the first (P = .01), second (P = .01), and third (P = .001) postoperative days between both groups, with more thigh pain on the 350 mmHg side. At 6 weeks after surgery, the difference in thigh pain was gone. For total knee arthroplasty, using the tourniquet at a pressure of 100 mmHg above the systolic blood pressure is recommended. This is adequate to provide a bloodless field and will result in a less unpleasant postoperative period.
TL;DR: The functional influence of patellofemoral design was evaluated by testing two cohorts of patients with total knee arthroplasty while walking, climbing stairs, and rising from a chair to suggest a relationship between a nonanatomic trochlea and abnormal function during stair-climbing.
Abstract: The functional influence of patellofemoral design was evaluated by testing two cohorts of patients with total knee arthroplasty while walking, climbing stairs, and rising from a chair. The two cohorts received one of two different designs of total knee arthroplasty. The designs differed primarily in the curvature of the femoral trochlea. These differences in curvature have been shown in in vitro studies to influence the tracking of the patella. One design had a smaller radius on the patellar flange, which caused the patella to articulate more anteriorly and distally than the second design, which had a larger radius in this region. The second design more closely replicated the curvature of the femoral trochlear anatomy. There was a significant functional difference during stairclimbing between the patient groups, whereas there was no difference during walking or chair rising. The group with the design that had nonanatomic tracking of the patella had a higher than normal moment tending to flex the knee (net quadriceps moment) during late stance phase. The increased net quadriceps moment during late stance was concurrent with an increased knee flexion. The abnormal function occurred when the patellar was tracking over the nonanatomic portion of the trochlea. Patients in the group with the anatomic trochlea did not have abnormal function. These results suggest a relationship between a nonanatomic trochlea and abnormal function during stair-climbing.
TL;DR: This review demonstrates that cemented total knee arthroplasty in younger patients with osteoarthritis and rheumatoid arthritis can attain results comparable to the excellent results obtained in the older age groups.
Abstract: Seventy-two cemented total knee arthroplasties were performed on 52 patients who were 55 years old or younger. Results on 68 knees in 50 patients with an average follow-up period of 9.92 years are reported. The average age of the patients was 50.7 years (range, 30–55) at the time of surgery. The diagnosis was osteoarthritis in 37 knees, rheumatoid arthritis in 29 knees, and ankylosing spondylitis in 2 knees. The average preoperative Knee Society knee score was 23, and the average follow-up knee score was 97. All knees were rated as good or excellent for knee score. The average latest function score was 75 (preoperative, 36). Both knees in one patient required revision for loose components. This review demonstrates that cemented total knee arthroplasty in younger patients with osteoarthritis and rheumatoid arthritis can attain results comparable to the excellent results obtained in the older age groups.
TL;DR: Tourniquet time and its relationship to blood loss and deep vein thrombosis were studied in 80 cases of unilateral total knee arthroplasty as part of a prospective multicenter double-blind study onThromboprophylaxis for knee surgery.
Abstract: Tourniquet time and its relationship to blood loss and deep vein thrombosis were studied in 80 cases of unilateral total knee arthroplasty. These data were part of a prospective multicenter double-blind study on thromboprophylaxis for knee surgery. This study reports on the cases done at one institution in which the tourniquet was used in three different ways: group 1, no tourniquet use; group 2, limited tourniquet use for cementing time only; group 3, tourniquet use throughout the whole case. Blood loss was significantly related to tourniquet time (P = .0001). The incidence of deep vein thrombosis was not related to the tourniquet group (P = .9).
TL;DR: It is concluded that performing simultaneous bilateral TKA does not result in any significant increase in patient morbidity or compromise in postoperative function when compared with unilateral TKA.
Abstract: Recent studies have reported increased morbidity associated with bilateral simultaneous total knee arthroplasty (TKA). The purpose of this study was to evaluate the morbidity and clinical outcome associated with simultaneous bilateral TKA in contrast to unilateral TKA. All primary TKAs, either unilateral or simultaneous bilateral, performed between May 1988 and July 1993 were retrospectively reviewed. Patients were evaluated using Knee Society scores both before surgery and a minimum of 6 months after surgery. In addition to routine demographics, patients were evaluated for the incidence of both local wound and systemic complications. It is concluded that performing simultaneous bilateral TKA does not result in any significant increase in patient morbidity or compromise in postoperative function when compared with unilateral TKA.
TL;DR: It is concluded that the risk of fatal PE after unilateral TKA and unicompartment knee arthroplasty is low and chemical thromboprophylaxis was used only in high-risk cases in which there was a history of previous thromboembolism or obesity.
Abstract: A consecutive series of 1,390 primary total knee arthroplasty (TKA) procedures (1,201 patients, 1,600 arthroplasties) performed between January 1980 and July 1994 were reviewed to establish the incidence of death from pulmonary embolism (PE). Nine hundred twenty-three bi- or tricompartment TKAs and 467 unicompartment TKAs were performed as one-stage procedures. Chemical thromboprophylaxis was used only in high-risk cases in which there was a history of previous thromboembolism or obesity. There were no deaths from PE after unicompartment arthroplasty procedures. Autopsy confirmed PE as the cause of death in 2 patients following bi- and tricompartment TKAs (0.22%; 95% confidence interval [CI], 0.03-0.8%). The incidence was higher for one-stage bilateral TKA as 1 of the autopsy-confirmed deaths occurred in this group 0.7% (95% CI, 0.02-3.78%). Two other deaths were certified without postmortem examination (pneumonia and myocardial infarction in each case). As PE could not be ruled out as the cause of death in the latter 2 cases, these were considered as possible PE deaths to provide the maximum possible death rate that could result. Thus, the maximum possible incidence of fatal PE after TKA without routine use of chemical anticoagulation was 0.4% (95% CI 0.1-1.1%). It is concluded that the risk of fatal PE after unilateral TKA and unicompartment knee arthroplasty is low. The risk of clinical, nonfatal thromboembolic events, which might themselves warrant prophylaxis, was not quantified in this article.
TL;DR: The clinical outcome of the cemented Charnley hip arthroplasty at follow-up periods of 16-25 years was evaluated retrospectively in patients aged 50 years or younger and female sex was associated with a better prognosis.
Abstract: The clinical outcome of the cemented Charnley hip arthroplasty at follow-up periods of 16–25 years was evaluated retrospectively in patients aged 50 years or younger. One hundred thirty-two of a total of 167 hip arthroplasties were studied. The overall probability of survival of the implant at 20 years was 75%. Survival of those with rheumatoid disease was 80% compared with 64% for those with osteoarthritis. Female sex was associated with a better prognosis. Accelerated wear was associated with decreased survival of the prosthesis. Varus orientation of the femoral component significantly influenced failure (P
TL;DR: A generic three-dimensional finite-element model of the upper half of the femur containing a cementing femoral stem of a total hip arthroplasty was developed to study those factors influencing cement strains near the tip of a cemented femoral component, suggesting that the single factor that most adversely influenced peak strains at or near thetip of the prosthesis was a thin cement mantle.
Abstract: A generic three-dimensional finite-element model of the upper half of the femur containing a cemented femoral stem of a total hip arthroplasty was developed to study those factors influencing cement strains near the tip of a cemented femoral component. This generic model was verified through another three-dimensional finite-element model that had been created based on the precise geometry of a cadaver femur implanted with a contemporary cemented femoral component. This cadaveric femoral reconstruction had been created with strain gauges embedded in the cement mantle and was then loaded under conditions simulating single leg stance and stairclimbing. By use of the cement strains measured experimentally in the cadaver femur, and comparison of them with those obtained from the finite-element model of that cadaver femur, it was possible to establish proper material properties, boundary conditions, and loading conditions for the generic model. The generic model was then modified parametrically to determine those factors that influence the strains occurring within the cement mantle near the tip of a cemented femoral component. These models suggest that the single factor that most adversely influenced peak strains at or near the tip of the prosthesis was a thin cement mantle. This effect was present both when the cement mantle was reduced in thickness and when a similar effect occurred by virtue of a varus or valgus placement of the stem. Factors that decreased the peak cement strains near the tip of the femoral stem included a more flexible stem and thicker cement mantles. This effect of a more flexible stem could be obtained by changing the modulus of the metal implant, by uniformly reducing the thickness of the stem, or by tapering the stem within the same bone geometry. Thicker cement mantles reduced both the axial and the shear strains occurring at the tip of the prosthesis. The presence or absence of a hole in the tip of the prosthesis per se, as for a centralizer, had no significant effect on the peak cement strains seen around the tip of the prosthesis; however, truncating the tip of the prosthesis from a hemisphere to a flat profile, which resulted in a sharp corner at the tip of the prosthesis, produced a 35% increase in cement strains at the tip as a result of a stress concentration effect. Thus, the common way of modifying the tip to have a hole for a centralizer, which involved truncating the tip, increased the cement strains occurring near the tip of the prosthesis.