Reproducing a functional flexion-extension axis (FEA) of the femur is key to achieving successful collateral ligament balance and joint line in total knee arthroplasty (TKA). This study assessed the feasibility of cylindrical axis (CA)-reference bone-cut and articular surface-reference bone-cut to reproduce FEA in Japanese osteoarthritis patients. The study enrolled 122 knees from 86 patients who underwent primary TKA due to grade III or IV osteoarthritis. Data from preoperative CT were reconstructed into 3-dimensional (3D) models using 3D-planning software. Cylindrical radii of the condyles were measured, and femoral bone-cut angles relative to anatomical landmarks were determined in the coronal and axial reference planes based on CA-reference and articular surface-reference methods.Purpose
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Wound condition after primary total knee arthroplasty (TKA) is important for prevention of periprosthetic infection. Any delay in wound healing will cause deep infection, which leads to the arthroplasty failure. Prevention of soft tissue problems is thus essential to achieve excellent clinical results. However, it is unknown as to the important surgical factors affecting the wound healing using detailed wound score after primary TKA so far. It was hypothesized that operative technique would affect wound healing in primary TKA. The purpose of the present study was to investigate and to clarify the important surgical factors affecting wound score after primary TKA. A total of 139 knees in 128 patients (mean 73 years) were enrolled. All primary TKAs were done by single surgeon. All patients underwent unilateral or bilateral TKA using Balanced Knee System®, posterior stabilized (PS) design (Ortho Development, Draper, UT) or Legion®, PS design (Smith and Nephew, Memphis, TN) under general and/or epidural anesthesia. Patients with immunosuppressive therapy, hypokalemia, poor nutrition (albumin < 3.4 g/dL), diverticulosis, infection elsewhere, uncontrolled diabetes mellitus (HbA1C>7.0%), obesity (Body Mass Index > 35 kg/m2), smoking, renal failure, hypothyroidism, alcohol abuse, rheumatoid arthritis, posttraumatic arthritis, and previous knee surgery were excluded. Hollander Wound Evaluation Score (HWES) was assessed on postoperative day 14. We evaluated age, sex, body mass index, HbA1C (%), preoperative femorotibial angle (FTA) on plain radiograph. In addition, intraoperative patella eversion, intraoperative anterior translation of the tibia, patella resurfacing, surgical time, tourniquet time, unidirectional barbed suture and length of skin incision were also evaluated as surgical factors. Multiple regression analysis was done using stepwise method to identify the surgical factors affecting HWES.Introduction
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A longer operative time will lead to the development of any postoperative complications in total knee arthroplasty (TKA). According to previous reports, a significant increase in TKA procedure time done by novice surgeons was observed compared to high-volume surgeons. Our purpose was to investigate and to clarify the important maneuver necessary for novice surgeons to minimize a surgical time in TKA. A total of 300 knees in 248 patients, averaged 74.6 ± 8.7 years, were enrolled. All primary TKAs were done using same instruments (Balanced Knee System®, PS design, Ortho Development, Draper, UT) and same measured resection technique at 14 facilities by 25 orthopedic surgeons. Surgeons were divided into three surgeon groups (4 experts, 9 medium volume surgeons, 12 novices). All methods were approved by our institution's ethics committee. We divided the operative technique into 5 steps to make comparisons of step-by-step surgical time among surgeon groups of different levels. We defined Phase 1 as performing surgical exposure from skin incision to insertion of the intramedullary rod into the femur. Thereafter, the distal and AP surface of the femur, proximal tibia, the chamfer and PS box of the femur, and patella were resected in Phase 2. In Phase 3, a setup the trial component and a keel of the tibia were done after a confirmation of appropriate ligament balance using the spacer block. Then, a bone surface was irrigated with 2000ml of saline after the removal of the trial component. Subsequently, permanent components were fixed with use of bone cement in Phase 4. Finally, the final irrigation using 2000ml saline and wound closure were done in Phase 5. Every phase of the surgical time was recorded in each TKA. As a statistical analysis, operation data including length of skin incision, component size, operation time in each phase, and ratio of surgical time in each phase to whole surgical time, were compared using non-repeated measures of ANOVA and a post hoc Bonferroni correction. The threshold for statistical significance was set at a p value of less than 0.05.Introduction
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Total knee arthroplasty (TKA) has traditionally been performed as an effective treatment for patients with end-stage knee OA, by relieving pain, restoring function, and correcting deformity. One-leg standing (OLS) test is a widely used clinical tool to evaluate postural steadiness in a standing position for elderly people. According to previous reports, one-leg standing time was associated with subjects' age, self-assessment of their health status, body mass index, mortality, and the risk of falls. Therefore, it is important to know knee condition including OLS in older patients with knee OA. However, it is unknown whether TKA will be really beneficial for OLS in the elderly people. It was hypothesized that postoperative recovery would be more slowly in older patients than in younger patients. Our purpose was to investigate factors affecting the OLS time in patients with end-stage knee OA and to clarify an age-related recovery process following TKA in the early postoperative period. A total of 80 knees in 40 patients (35 females and 5 males) were enrolled in the current investigation. Mean age was 75 (60–82) years old. All the patients had bilateral varus deformities with radiographic OA of grade 4 severities, according to Kellgren-Lawrence grade. All the patients were divided into 2 Groups; patients older than 76 years (Group O) and younger than 75 years (Group Y). After unilateral TKA using Balanced Knee System®, posterior stabilized design (Ortho Development, Draper, UT), postoperative evaluations including OLS time, knee flexion angle during standing (KFA), and Visual Analogue Scale (VAS), were done preoperatively and daily from postoperative day 3 to 20 in each group, because epidural catheter was removed on postoperative day 2. As a statistical analysis, values of preoperative measurements were used as controls in each group. Statistical difference between the data was evaluated using two-tailed repeated-measures of analysis of variance (ANOVA). After a significant P value (< 0.05) was determined, a post hoc Dunnett test was performed to compare selected mean values, and P-values of < 0.05 was considered as significant.Introduction
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Skin closure methods are various in total knee arthroplasty (TKA). Subcuticular skin closure techniques, which do not require postoperative stitch removal, are considered to be useful for excellent cosmesis and patients' satisfaction. Basically, subcuticular skin closure provides the tightness and water-tight seal, which leads to loss of postoperative normal physiologic drainage. As a routine wound closure, we performed the subcuticular skin closure with use of absorbable sutures or barbed sutures without staples. According to some previous reports, subcuticular skin closure using barbed sutures resulted in worse clinical outcomes, comparing with conventional skin staples. However, little attention has been paid to the differences between conventional absorbable and barbed sutures in both capsular and subcuticular skin closures. Our purpose was to investigate the efficacy and safety of the barbed suture, comparing to conventional absorbable sutures in TKA. A total of 81 knees in 75 patients (60 females and 15 males) were enrolled in the current investigation. Mean age was 73 (58–89) years old. All the subjects underwent unilateral or staged bilateral TKA using Balanced Knee System, posterior stabilized design (Ortho Development, Draper, UT). All knees were divided into two groups, as presented in Table 1. In conventional group, capsule was repaired using interrupted number 1 braided absorbable sutures, followed by closure of subdermal layer using a 3-0 monofilament absorbable suture with inverted interrupted knots. Thereafter, subcuticular skin closure was done using 4-0 monofilament absorbable suture, followed by adhesive tape. On the other hand, in barbed suture group, 1-0 and 4-0 unidirectional barbed suture (V-Loc, Covidien, Mansfield, Massachusetts) was used for capsule and subcuticular skin closure, respectively. Drains were removed on postoperative day 2. We evaluated closure time from capsule to skin, range of motion (ROM), Hollander Wound Evaluation Score (HWES: maximum score 6/6), and complications. Postoperative ROM and HWES were evaluated on postoperative day 14. As a statistical analysis, the data was compared between groups using Mann-Whitney U-test and Fisher exact probability test. P-values of < 0.05 were considered as significant.Introduction
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According to previous reports, unilateral total knee arthroplasty (TKA) would produce the asymmetric changes of lower extremity in the coronal plane in patients with bilateral knee osteoarthritis (OA). To our knowledge, little attention has been paid to the alignment changes of trunk and contralateral limb. It was hypothesized that the unilateral correction of knee deformity would affect trunk bending in the coronal plane after unilateral total knee arthroplasty. The purpose of the current study was to investigate trunk bending in the coronal plane before and after the surgery. Twenty patients (17 Females and 3 Males; mean 76 years old) with bilateral symptomatic knee osteoarthritis participated. They had radiographic bilateral OA of at least grade 3 severities according to the Kellgren-Lawrence scale. All the subjects underwent unilateral TKA using Balanced Knee System®, posterior stabilized design (Ortho Development, Draper, UT). All the subjects provided informed consent. All methods and procedures were approved by our institution's ethics committee. They were asked to step on the two scales and perform relaxed standing for five seconds, placing each foot on each scale independentlys. Thereafter, anteroposterior radiographs of the whole spine and bilateral long legs were taken with use of a vertical 35.4 × 101.7-cm film. The shoulder tilting angle was defined by the height difference between the centers of the right and left acromioclavicular joints, and the pelvic tilting angle was defined by the height difference between the centers of the right and left femoral heads. To evaluate trunk bending, the shoulder-pelvis bending angle was defined as the angle between the shoulder girdle line (Fig. 1, Line a) and the pelvic line (Fig. 1, Line b). Femorotibial angle (FTA) was also evaluated. These radiographs were taken before the surgery and on postoperative day 21. Simultaneously, knee flexion angles on TKA side, subjective pain level on TKA side and vertical knee forces (% body weight; BW) on TKA side during relaxed standing were also examined. Data evaluations were done both before and on postoperative day 21. Statistical difference between the data was evaluated using two-tailed Wilcoxon t-test. P-values of < 0.05 were considered as significant.Introduction
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Length of hospital stay in Japan is 20 to 30 days, which is much longer than United States. Reasons of such differences are utilization of a national insurance system in Japan, and more than 90 % of patients are discharged to home. The purpose of the current study was to investigate inpatient recovery process during relaxed standing, and to clarify the appropriate length of hospital stay following TKA. Thirty patients (25 Females and 5 Males) with knee osteoarthritis, 67 to 84 years old (mean 75), participated. All the subjects provided informed consent and the study was approved by our institution. The subjects were asked to step on the two scales and perform relaxed standing, placing each foot on each scale independently. Evaluations were divided into two categories; subjective and objective components. Subjective component was based on pain level, and objective component consisted of vertical knee force and knee flexion angle during relaxed standing. Namely, subjective pain level on TKA side, vertical knee forces (%BW) on TKA side, and knee flexion angles (degrees) on TKA side during relaxed standing, were examined. Each evaluation was done twice. Data evaluations were done pre- and post-operatively. Postoperative evaluations were done daily from postoperative day 3 to 21. Pain level, vertical knee force, and knee flexion angle were evaluated using visual analog scale (100 mm), same type of two scales, and goniometer, respectively. Vertical knee force (%BW) was defined as the ratio of weight bearing on TKA side to body weight in our study. An average value of two trials was calculated. Values of preoperative measurements were used as controls. Statistical difference between the data was evaluated using two-tailed repeated-measures of analysis of variance. After a significant P value (< 0.05) was determined, a post hoc Bonferroni correction was performed to compare selected mean values, and P-values of < 0.05 was considered as significant.Introduction
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