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The objective of this study is to assess preoperative patient expectations of medial opening wedge high tibial osteotomy (MOWHTO) and related postoperative fulfillment, to increase understanding of associated factors of postoperative satisfaction.One hundred fifteen patients who underwent MOWHTO were enrolled. Patients' expectations were measured using the Hospital for Special Surgery-Knee Replacement Expectations Survey. Fulfillment of expectations and satisfaction was evaluated using the Hospital for Special Surgery Knee Replacement Fulfillment of Expectations Survey and a 5-point Likert scale at 2 years, postoperatively. The discrepancies between preoperative expectation and postoperative fulfillment score were also assessed. Preoperative and postoperative patient-reported outcomes were evaluated using Western Ontario and McMaster Universities Arthritis Index (WOMAC) score. Univariate and multivariate analyses were performed to model predictions for satisfaction.The most expected items were "pain relief," "walking ability," and "perform daily activities." The top 3 items with the biggest discrepancies between expectation and fulfillment scores were "kneeling," "squatting," and "pain relief." Ninety patients (78.3%) were satisfied and 25 (21.7%) were dissatisfied at 2 years postoperative. Multivariate logistic regressions showed that patient expectations did not affect satisfaction. Small discrepancies between expectation and fulfillment scores (odds ratio [OR] 105.304, 95% confidence interval 20.974-528.714, P.001), high postoperative fulfillment scores (OR 1.198, 95% CI 1.110-1.293, P.001), and low postoperative Western Ontario and McMaster Universities Arthritis Index total scores (OR 0.932, 95% CI 0.894-0.971, P.001) were significantly associated with patient satisfaction.The small discrepancy between preoperative expectations and postoperative fulfillment of expectations was a major contributor to patients' satisfaction following MOWHTO.

Background This study aims to investigate how expectation fulfillment changes up to 10 years following total knee arthroplasty (TKA). Methods Preoperative data were collected for 323 patients undergoing TKA (Hospital for Special Surgery Knee Replacement Expectations survey, Oxford Knee Score [OKS], and Short Form [SF]-12). Expectation fulfillment, OKS, SF-12, and patient satisfaction were assessed at 1 year and 9-10 years postoperatively. Relative risk (RR) of dissatisfaction at late follow-up was calculated for each specific expectation question. Linear regression analysis was used to identify factors independently associated with early (1 year) and late (mean 9 years) expectation fulfillment scores. Results Mean expectation fulfillment scores declined from early to late follow-up (25.9-23.9, P = .025). Multivariate analysis identified younger age and better 1-year OKS as factors independently associated with long-term expectation fulfillment. Twelve percent of patients reported dissatisfaction at late follow-up. The risk of long-term dissatisfaction was greatest in patients with high preoperative expectations of kneeling (RR 2.2, 95% confidence interval [CI] 0.9-5.5), walking without aids (RR 2.4, 95% CI 0.7-7.6), and improved psychological well-being (RR 3.9, 95% CI 0.9-5.0). Night pain relief, kneeling ability, participating in outside activities, and sports were the most poorly fulfilled expectations at both early and late time points. Fulfillment improved the least from early to late for kneeling ability (17%) and ability to participate in outside activities (17%). Conclusion Expectation fulfillment following TKA changes with time. Expectations of kneeling ability and the ability to perform outside activities demonstrated persistently low levels of fulfillment. This information can be used to manage the longer term expectations of patients undergoing TKA.

Background Recent clinical studies have suggested that systemic metal ion levels are significantly elevated at midterm follow-up in patients with ceramic-on-metal (COM) bearing. However, it is not clear whether there is a correlation between patient-related factors including the lifestyle and elevated levels of serum metal ions following COM total hip arthroplasty (THA). Methods Serum metal levels were measured in 201 patients (234 hips) including 121 COM patients (140 hips) and 80 non-COM patients (94 hips). The Harris Hip Score, University of California, Los Angeles activity scale score, and Western Ontario and McMaster Universities Osteoarthritis Index score were measured and radiographs were obtained for the analysis. Results Significantly higher levels of cobalt (Co) and chromium (Cr) were detected in the serum of the COM THA group (Co: 1.86 ± 4.0 μg/L; Cr: 1.81 ± 2.87 μg/L) than those of the non-COM THA group (Co: 0.27 ± 0.14 μg/L; Cr: 0.19 ± 0.25 μg/L; P The serum metal levels of patients who achieved the squatting position and the kneeling position were significantly higher than those of patients who could not squat (Co: P = .033; Cr: P = .074) and kneel (Co: P = .049; Cr: P = .031). The metal ion levels of the COM THA group correlated with the total range of motion (Co: P = .0293; Cr: P = .0399). Conclusion Patients who underwent a 36-mm COM THA showed high serum metal levels although good clinical outcomes at the midterm follow-up. We found that COM THA patients who were capable of greater range of motion, squatting, and kneeling are at risk of metal ion–related problems.

Background Sexual limitations in the setting of total knee arthroplasty (TKA) are poorly understood. Methods Surveys were designed to assess preoperative and postoperative sexual function, and limitations were retrospectively administered to 91 sexually active TKA patients at an average of 2.1 years (range, 0.5-4.0) after surgery. Preoperative and postoperative responses were compared using 1-tailed and 2-proportion z tests, with P Results Before TKA, sexual quality and/or frequency was limited in 45% of patients because of their knee. Patients experienced an average 17.1 months (range, 0-60) of sexual limitations before surgery, resulting largely from pain (87%) and diminished range of motion or flexibility (44%). Fifty-five percent of patients reported the need to change their sexual positions to accommodate their knee, with 97% of these patients indicating the need to avoid kneeling during sex. Postoperatively, fewer patients had to adjust their sexual positions to accommodate their knee (55% vs 28%, P = .0005), and avoid bearing weight on the afflicted knee during sex (97% vs 79%, P = .0213). Patients resumed sexual activity after an average of 2.4 months (range, 0-18). Despite these general improvements, 25% of individuals had less sex in the first year after surgery. After 1 year of recovery, however, 60% indicated that they more easily engaged in sexual activity than in the previous year, with 84% of these patients experiencing less pain, and 30% experiencing greater mobility or range of motion. Conclusion TKA does not eliminate sexual limitations, but it significantly decreases kneeling dysfunction and gives patients more liberty in selecting their sexual positions.

Background Patients commonly report difficulty kneeling after total knee arthroplasty (TKA). The purpose of this study was to retrospectively assess patients’ ability to kneel after TKA and to prospectively determine whether patients with reported difficulty can be taught to kneel. Methods Attempts were made to reach 307 consecutive TKAs in 255 adult patients who were 18-24 months after surgery. Patients were surveyed for their ability to kneel. Those who reported difficulty kneeling were offered participation in a kneeling protocol. At the conclusion of the protocol, participants were surveyed again for their ability to kneel. Results Of the 307 consecutive TKAs, 288 knees (94%) answered the survey. Of them, 196 knees (68%) could kneel with minor or no difficulty without any specific training. And 77 knees (27%) reported at least some difficulty kneeling and were eligible for participation in the protocol. Pain or discomfort was the most commonly reported reason for difficulty kneeling. Of these 77 knees, 43 knees (56%) participated. Thirty-six knees (84%) completed all or most of the protocol. All patients who completed all or most of the protocol were then able to kneel, and none reported significant difficulty kneeling. On average, participants improved 1.4 levels. Conclusion In this cohort, 68% of knees could kneel after TKA without any specific training. Of those who had at least some difficulty kneeling, all who participated were able to kneel after a simple kneeling protocol, although 44% of eligible patients did not participate. This study suggests that kneeling should be included in postoperative TKA rehabilitation.

Kneeling is an important function of the knee joint required for many daily activities. Bearing type is thought to influence functional outcome following UKA and TKA. Self-reported kneeling ability was recorded in 471 UKA and 206 TKA patients with fixed or mobile bearing implants. Kneeling ability was recorded from the Oxford Knee Score question 7. The self-reported ability to kneel was similar in patients with fixed and mobile bearing UKA implants following surgery. In TKA, greater proportions of patients were able to kneel in the fixed compared to the mobile bearing groups up to two years after surgery indicating that self-reported kneeling ability is enhanced in fixed compared to mobile bearing TKA.

Background Anterolateral skin incision can preserve the skin sensory of the anterior aspect of the knee and may improve kneeling ability after total knee arthroplasty (TKA). Methods This is a prospective, 2-arm, parallel-group, randomized, controlled trial involving patients scheduled for TKA. A total of 118 patients (162 knees) were randomly assigned to receive anterolateral skin incision or anteromedial skin incision with 1:1 treatment allocation. The surgical techniques other than skin incision were identical in both groups. The area of cutaneous hypesthesia was measured by a nonblinded assessor, and kneeling ability was evaluated by 2 blinded assessors at 12 months after surgery. Results The area of cutaneous hypesthesia was significantly smaller in the anterolateral skin incision group than the anteromedial skin incision group (3.0 ± 8.7 cm2 vs 10.6 ± 18.6 cm2; 95% confidence interval, 2.8-12.3 cm2; P = .0019). The rates of patients judged to be able to kneel were significantly higher in the anterolateral skin incision group by both assessors (81% vs 60%; P = .025 and 81% vs 59%; P = .015, respectively) with almost perfect agreement between the 2 assessors (kappa value = 0.94). There were no significant differences in terms of complication rate, including wound complications, between the 2 groups (P > .05). Conclusion Compared with anteromedial skin incision, anterolateral skin incision may provide less cutaneous hypesthesia and better kneeling ability after TKA without increasing complication rate.

There is a paucity of information on the relationships between postoperative knee laxity and in vivo knee kinematics. The correlations were analyzed in 22 knees with axial radiographs and fluoroscopy based 3D model fitting approach after a tri-condylar total knee arthroplasty. During deep knee bend activities, the medial flexion gap had significant correlations with the medial contact point (r=0.529, P=0.011) and axial rotation at full extension. During kneeling activities, a greater medial flexion gap caused larger anterior translation at complete contact (r=0.568, P=0.011). Meanwhile, the lateral flexion gap had less effect. In conclusion, laxity of the medial collateral ligament should be avoided because the magnitude of medial flexion stability was crucial for postoperative knee kinematics.

Background Patellofemoral chondromalacia (PFCM) has historically been considered a contraindication for unicompartmental knee arthroplasty (UKA), but there is limited data assessing PFCM's impact on the results of fixed-bearing UKA. Our objective was to assess the impact of medial patellar and/or medial trochlear PFCM on overall and patellofemoral-specific 2-year outcomes after fixed-bearing medial UKA. Methods Intraoperative notes defined the presence and location of PFCM during fixed bearing medial UKA. Outcome measures included the New Knee Society Score (NKSS), Kneeling Ability Score (KAS) and Forgotten Joint Score (FJS-12). Thirty-one knees with PFCM ( PFCM group), and 52 knees without PFCM ( N-PFCM group) were included for analysis. Mann-Whitney U tests assessed the statistical significance of observed differences, and a Bonferroni correction was applied, adjusting threshold for significance to P = .005. Results At minimum follow-up of 2 years, no statistical differences were detected between the N-PFCM and PFCM groups in the postoperative NKSS (159 vs 157, P = .731), preoperative to postoperative NKSS change ( P = .447), FJS-12 (70.5 vs 67.6, P = .471), or KAS (71% vs 65%, P = .217). Patients with isolated patellar chondromalacia (n = 13) demonstrated trends toward worse outcomes according to NKSS (147, P = .198), FJS-12 (58, P = .094), and KAS (46%, P = .018), but were statistically insignificant. No failures occurred in either group. Conclusion Functional outcomes of fixed-bearing medial UKA are not adversely impacted by the presence of PFCM involving the medial patellar facet and/or medial or central trochlea. Further follow-up is needed to determine longer-term implications of fixed-bearing medial UKA in patients with PFCM.

Our hypothesis was that a high-flexion rotating-platform posterior stabilized (RP-PS) design could maximize range of motion (ROM) and improve deep-flexion activities. Eighty-seven consecutive patients (109 knees) with high-flexion RP-PS design were prospectively followed up for a minimum of 3 years. Radiographic and clinical outcomes were analyzed using Knee Society Score criteria and Western Ontario and McMaster Universities Osteoarthritis Index. Good to excellent clinical scores were achieved in 96% of the knees. There were no cases of infection, malalignment, loosening, osteolysis, or spinout. The mean preoperative ROM improved from 110.7° to 124° postoperatively. High-flexion activities such as squatting and kneeling were achieved in 62% and 60% of patients, respectively. High-flexion knee implant is safe and improves ROM and deep-flexion activities. Persistent pain is an important cause of dissatisfaction after total knee arthroplasty.

Orthopedic surgeons and their patients continue to seek better functional outcomes after total knee arthroplasty. The bicruciate substituting (BCS) total knee arthroplasty design has been introduced to achieve more natural knee mechanics. The purpose of this study was to characterize kinematics in knees with BCS arthroplasty during deep flexion and stair activities using fluoroscopy and model-image registration. In 20 patients with 25 BCS knees, we observed average implant flexion of 128° during kneeling and consistent posterior condylar translations with knee flexion. Tibial rotations were qualitatively similar to those observed in the arthritic natural knee. Knee kinematics with BCS arthroplasty were qualitatively more similar to arthritic natural knees than knees with either posterior cruciate-retaining or posterior-stabilized arthroplasty.

The sensation of numbness, prosthesis noise production, and kneeling difficulties are generally considered, by most surgeons, minor issues after total knee arthroplasty, but their frequency and relationship to patient expectations and satisfaction have been seldom described. We analyzed 49 patient responses to both an Oxford Knee Score and a separate questionnaire with specific questions about numbness, kneeling, and noise. Of these patients, 69% reported noise production, 71% reported numbness, and 82% reported kneeling difficulties. The mean scores for the magnitude of numbness and kneeling difficulties improved between the time frames of less than 6 months and more than 6 months postoperation, whereas noise scores worsened. None of these changes were statistically significant at the 5% level. Combinations of these issues do affect patient satisfaction and are greater for patients more than 6 months postoperation. A preoperative patient education program, informing patients about these issues, may improve patient satisfaction.

Many younger and highly active patients desire to achieve high flexion after total knee arthroplasty. This study's purpose was to determine if a contemporary total knee arthroplasty design improved functional knee flexion compared with a traditional total knee arthroplasty in patients living a Western lifestyle. Ten patients with bilateral total knee arthroplasty of 2 types were studied during weight-bearing lunge, kneeling, and stair activities using fluoroscopic imaging. There were no differences in maximum knee flexion during lunging or kneeling. Statistically significant differences in tibial rotation and condylar translation were observed during the 3 activities. Although several joint kinematic differences were observed, no important functional differences were observed in clinically excellent, high performing subjects with bilateral total knee arthroplasty of 2 types.

Nine ADVANCE (Wright Medical Technology, Arlington, TN)) Medial-Pivot (MP) and 9 ADVANCE Double-High total knee arthroplasties were analyzed under radiographic surveillance at standing, mid kneeling, and full kneeling. In vivo tibiofemoral contact positions were obtained using the 3- to 2-dimensional image registration technique. The contact in Double-High knee was always more posterior than that in the MP knee presumably because of the presence of the posterior cruciate ligament. The contact positions in both the designs moved anterior from standing to mid kneeling, moved posterior from mid kneeling to full kneeling, and remained within the intended articulation range of the implants. This study indicates that kneeling is safe in MP total knee arthroplasty even in the absence of a cam-post or posterior cruciate ligament.

Full flexion is critical for total knee arthroplasty (TKA) patients in the Middle East, where daily activities require a high range of motion in the lower limb. This study aimed to increase understanding of the knee kinematics of normal Muslim subjects during high-flexion activities of daily living, such as kneeling, Muslim prayer, sitting cross-legged, and squatting. The early postoperative kinematics for a select group of Muslim, high-flexion TKA patients are also reported. Mean curves were compared between the normal group and the TKA group. During kneeling, the average maximum flexion was 141.6° for the normal group and 140.2° for the TKA group. The normal group's maximum and minimum knee angles (flexion, abduction, external rotation) were reported and, with the exception of maximum extension, were not significantly different from the TKA group, despite short postoperative times.

Achieving very deep flexion after total knee arthroplasty is an important goal of most patients in Japan, Asia, and the Middle East because of floor-sitting lifestyles. Numerous knee arthroplasty designs have been introduced to permit high flexion. We performed an in vivo radiographic analysis of tibiofemoral motions during weight-bearing kneeling in one high-flexion knee arthroplasty design. Twenty knees implanted with a posterior-stabilized rotating-platform knee arthroplasty flexed an average of 126 degrees. The femoral condyles translated posteriorly from extension to maximum flexion. Total posterior condylar translations averaged 11.6 and 4.7 mm for the lateral and medial condyles, respectively. Tibial internal rotation in 19 knees averaged 9 degrees from extension to maximum flexion. Knees implanted with a posterior-stabilized, rotating-platform knee arthroplasty show deep flexion knee kinematics consistent with the implant design intent.

Achieving deep knee flexion145 degrees is a goal of many patients receiving knee arthroplasty in Asia and the Middle East, yet it is unknown whether knees with implants move similar to the natural knee in these postures. We studied 18 of 36 consecutively operated knees that were able to flex145 degrees using fluoroscopic analysis during kneeling to maximum flexion. An average of 9 degrees tibial internal rotation was observed in deep flexion. Posterior condylar translations were observed from 80 degrees to 120 degrees flexion, and the condyles translated forward in flexion beyond 120 degrees. Separation of the condyles from the tibial surface was observed in 9 knees at flexion130 degrees. Very deep flexion can be achieved and is well accommodated using contemporary posterior-stabilized knee arthroplasty, but the kinematics differ from the intact natural knee.

Some surgeons warn against kneeling after total knee arthroplasty (TKA), because limited clinical data exist. We describe the tibiofemoral contact position of TKA components during kneeling in vivo. Ten posterior-substituting (PS) and 10 cruciate-retaining (CR) designs were examined using a radiographic image-matching technique. Movement from standing to kneeling at 90 degrees produced different responses. CR knees translated anteriorly (medial, 4 +/- 4 mm; lateral, 2 +/- 6 mm). PS knees underwent little posterior translation (medial, 0.2 +/- 3 mm; lateral, 1 +/- 4 mm). Movement from 90 degrees to maximum flexion produced femoral posterior translation (CR medial, 5 +/- 4 mm; CR lateral, 5 +/- 4 mm; PS medial, 6 +/- 4 mm; PS lateral, 6 +/- 3 mm). The relationship between tibiofemoral contact position and flexion angle was more variable for CR (r2=.38) than for PS (r2=.64). Knee kinematics was similar to other deep-flexion weight-bearing activities.

Computed tomography (CT) has been used to assess the rotational alignment of the distal femur. The purpose of this study was to establish a simple radiographic technique to evaluate the posterior femoral condyles. For this study, 39 osteoarthritic knees and 19 normal knees were examined. The condylar twist angle and posterior condylar angle were measured using a new roentgenographic technique ("the kneeling view") and CT images. The kneeling view is a posteroanterior projection parallel to the articular surface with 80 degrees knee flexion. In this view, the transepicondylar axis and posterior condylar line can be seen. We noted statistically significant correlation between the angles on the kneeling view and those on CT images. Therefore, the kneeling view can be used as a substitute for CT in the measurement of rotational alignment of the distal femur.

The objective of this study was to determine the in vivo medial and lateral femorotibial condyle contact positions for 20 subjects having either a posterior cruciate–retaining (PCR) or posterior-stabilized (PS) total knee arthroplasty (TKA) while sitting and kneeling. The two-dimensional radiographic images were converted into three-dimensional images using an iterative computer model-fitting technique. Anteroposterior contact positions, axial rotation, and condylar lift-off were assessed for each subject. In a seated position, the femorotibial contact points were, on average, posterior for both TKA groups (PCR: medial=−2.4 mm, lateral=−3.4 mm; PS: medial=−5.1 mm, lateral=−8.9 mm; medial, P =.21; lateral, P =.08). In a kneeling position, the contact position shifted anteriorly for the PCR TKA group (medial = 0.9 mm, lateral=−0.8 mm), whereas the contact positions in the PS TKA group remained posterior (medial = −5.6 mm, lateral=−8.3 mm; medial, P =.002; lateral, P =.0004). It is hypothesized that while in a kneeling position, the posterior cruciate ligament has less resistance to the anterior thrust of the femur relative to the tibia than in a PS TKA, in which this force is absorbed in the cam-and-post mechanism.

Few studies have compared functional kinematics in knees using identical prostheses with or without the posterior cruciate ligament (PCL). This study contrasted in vivo knee kinematics with an anterior cruciate ligament-substituting arthroplasty with and without PCL retention. We hypothesized that knees without PCLs would exhibit less femoral posterior translation, and consequently less maximum knee flexion. Fifty-six knees were studied using dynamic radiography at least one year post-surgery, with twenty-seven knees retaining the PCL and twenty-nine knees having the PCL sacrificed. Consistent with our hypothesis, PCL-sacrificing knees showed more anterior femoral condylar positions. Contrary to our hypothesis, PCL-sacrificing knees demonstrated greater knee flexion during kneeling (122° versus 115°). Contracted PCLs in severely deformed knees likely were the cause of limited flexion in some retaining knees.

We developed a new posterior-stabilized total knee arthroplasty (TKA) with a unique post-cam design that induces and accommodates internal tibial rotation with deep knee flexion. To validate the design concept of this system, we conducted an image analysis study employing a computer-aided diagnosis system for 24 TKA-implanted knees. In the analysis, the tibiofemoral relationship in the following 3 postures was evaluated: standing at extension, forward lunge, and kneeling with maximum knee flexion. The results of the image analysis showed achievement of consistent internal rotation of the tibia in deep flexion with a broad contact area at the post-cam interface as intended by the original design concept of this TKA system.

The objective of this study was to measure the effect of kneeling on tibiofemoral contact following cruciate-retaining and posterior-stabilized total knee arthroplasty. Five cadaveric knees were tested on a custom testing system that allowed physiologic muscle loading. Three forces were used to simulate nonkneeling, double-stance kneeling, and single-stance kneeling at flexion angles of 90°, 105°, 120°, and 135°. Tibiofemoral contact areas and pressures were measured using the Tekscan (South Boston, MA) system. Kneeling increased contact areas and pressures in both designs with variable significance (P < .05). Moving from double- to single-stance kneeling increased pressures in the cruciate-retaining group but decreased pressures in the posterior-stabilized group (P < .05). Chronic, repetitive kneeling after total knee arthroplasty may increase polyethylene wear due to increased contact areas and pressures.

This study was conducted to investigate functional disabilities and patient satisfaction in Korean patients after total knee arthroplasty (TKA). Of 372 female patients who had undergone TKA with a follow-up longer than 12 months, 261 patients (70.2%) completed a questionnaire designed to evaluate functional disabilities, perceived importance, and patient satisfaction. The top 5 severe functional disabilities were difficulties in kneeling, squatting, sitting with legs crossed, sexual activity, and recreational activities. The top 5 in order of perceived importance were difficulties in walking, using a bathtub, working, recreation activities, and climbing stairs. Severities of functional disabilities were not found to be correlated with perceived importance. The 23 patients (8.8%) dissatisfied with their replaced knees had more severe functional disabilities than the patients satisfied for most activities. The dissatisfied patients tended to perceive functional disabilities in high-flexion activities to be more important than the satisfied.

The purpose of this study was to evaluate the rotational kinematics of a fixed-bearing posteriorly stabilized total knee design in moderate and deep flexion. Three-dimensional kinematics analyses were conducted on 20 knees in 4 weight-bearing positions using 3-dimensional shape-matching techniques. Average maximum skeletal flexion was 138 degrees . Internal tibial rotation was demonstrated in 19 of 20 knees. The average internal tibial rotation in midflexed lunge was 5.5 degrees (-3.8 degrees to 14.1 degrees ) and in maximum flexion kneeling was 4.0 degrees (-3.1 degrees to 10.6 degrees ). Separation of articular surfaces was not identified. In this study, patients with this device demonstrated patterns of rotation similar to those previously reported for both the normal knee and rotating platform designs.

This study illustrates differences in the cartilage degeneration in osteoarthritic knees in patients with more frequent hyperflexion activities of daily living compared with Western patients. Proximal tibial articular cartilage wear and cruciate ligament condition were assessed in Saudi Arabian and North American patients with varus osteoarthritis undergoing total knee arthroplasty. In anterior cruciate ligament (ACL) intact knees, there were significant differences in wear location, with a clearly more anterior pattern in Saudi Arabian knees. Complete ACL deficiency occurred in 25% of North American knees but only 14% of Saudi Arabian knees. These ACL-deficient knees showed the most severe cartilage wear in both groups and posterior medial wear patterns. Biomechanical descriptions of knee flexion and axial rotation during kneeling or squatting are consistent with the more pronounced anteromedial and posterolateral cartilage wear patterns observed on the Saudi Arabian knees. These observations provide insight into altered knee mechanics in 2 culturally different populations with different demands on knee flexion.

Deep flexion activities including kneeling are desired by patients after total knee arthroplasty. This in vivo radiographic study sought to reveal the effect of tibial insert design on tibiofemoral kinematics during kneeling. One group of patients received standard posterior stabilized tibial inserts, whereas the other group received posterior stabilized tibial inserts (Flex inserts) that were designed to allow more flexion. The patients with the Flex inserts achieved greater range of motion without different tibiofemoral contact behavior.

We report a case of ceramic liner fracture in a 34-year-old man that occurred 1 year 9 months after total hip arthroplasty with a BiCONTACT (Aesculap, Tuttlingen, Germany) ceramic-on-ceramic prosthesis. The ceramic liner was found within the metal shell in 4 large pieces and multiple small fragments in the peripheral portions. Its condition indicated that the possible mechanism of late ceramic liner chip fracture was repeated episodes of impingement between the prosthetic neck and the edge of the ceramic liner. Squatting, kneeling, and sitting cross-legged caused impingement. These positions are more common in Asian populations than in Western populations. After the joint was thoroughly irrigated, a new modular ceramic liner and a 28-mm ceramic head were implanted.

This study tests the hypothesis that patients receiving a posterior cruciate ligament (PCL)-retaining prosthesis have no difference in functional outcome compared to those receiving a cruciate-sacrificing, posterior-stabilized (PS) design. Forty-nine patients underwent a total knee arthroplasty (TKA), performed by a single surgeon using the same implant design with either a PCL-retaining or a PS tibial insert. Each patient completed a self-administered, validated Total Knee Function Questionnaire as well as the SF-36. At 1-year follow-up, each patient's range of motion and Knee Society knee score were measured. There were no statistically significant differences between the 2 groups using the traditional measures of function following total knee replacement, including overall satisfaction with surgery. However, the TKFQ revealed that patients with PS knees reported greater functional limitations in squatting, kneeling, and gardening. Our results suggest that with the specific implant used in this study, substitution for the PCL with a spine and cam mechanism may not fully restore the functional capacity of the intact PCL, particularly in high-demand activities that involve deep flexion.

The number of patients receiving a TKA during working life is increasing but little is known about the impact of TKA on patients' reintegration into the workplace. In this cross-sectional survey it was found that 173 of 480 responders worked within 2 years prior to surgery. Sixty-three percent of the working patients stopped within two weeks prior to surgery and 102 patients returned within 6 months. One third never returned to work. Activities that most improved were operating foot pedals, operating vehicles, standing and walking on level terrain. Activities that least improved were kneeling, crouching and clambering. Fifty patients scored 5 or less on the Work Ability Index. Thirty patients were dissatisfied. TKA significantly, but unequally, reduces difficulties in carrying out knee-burdening work activities. (C) 2014 Elsevier Inc. All rights reserved