Total knee arthroplasty for primary knee osteoarthritis: Changing pattern over the past 10 years

Objective: To review the epidemiology of total knee arthroplasty for primary osteoarthritis and the change of patient characteristics over the last decade. Design: Retrospective review. Setting: A tertiary referral centre for joint replacement surgery in a teaching hospital in Hong Kong. Patients: All patients who underwent primary total knee arthroplasty for primary knee osteoarthritis from January 2000 to December 2009. Results: In all, 1157 total knee arthroplasties (589 left and 568 right) were performed on 588 females and 162 males. The annual number of total knee arthroplasties increased from 91 in 2000 to 181 in 2009. The annual number of patients increased from 58 (46 female, 12 male) in 2000 to 159 (117 female, 42 male) in 2009. When compared yearly results, there were no significant changes in the preoperative Knee Society Knee Score, Knee Society Functional Assessment, and passive range of motion of these patients. However, there was a significant decreasing trend with regard to lower limb mechanical axis mal-alignment, from 15.1° deviation from the neutral axis in 2000, to 14.8° deviation in 2004, and then 12.9° deviation in 2009 (mostly varus deformity). There was no difference between left knees and right knees, and between females and males. The mean age of the patients did not show significant change over the past decade, but the number and proportion of patients over 80 years old showed an increase from 4.8% (2000 to 2004) to 13.8% (2005 to 2009). On the other hand, the number and proportion of patients under the age of 60 years did not change. Conclusions: There was an increasing trend towards total knee arthroplasties, both in terms of number of operations and patients. The number of younger patients having total knee arthroplasty did not increase over the last 10 years, whereas the number of those older than 80 years increased significantly over that period.published_or_final_versio

Comparing two-phase locking and optimistic concurrency control protocols in multiprocessor real-time databases

Previous studies (Haritsa et al., 1990) have shown that optimistic concurrency control (OCC) generally performs better than lock-based protocols in disk-based real-time database systems (RTDBS). We compare the two concurrency control protocols in both disk-based and memory-resident multiprocessor RTDBS. Based on their performance characteristics, a new lock-based protocol, called two phase locking-lock write all (2PL-LW), is proposed. The results of our performance evaluation experiments show that different characteristics of the two environments indeed have great impact on the protocols' performance. We identify such system characteristics and show that our new lock-based protocols, 2PL-LW, is better than OCC in meeting transaction deadlines in both disk-based and memory-resident RTDBS.published_or_final_versio

股骨旋轉的放射學評估：屍體標本研究

Purpose: To define how the lesser trochanter can be used in an objective manner to assess the femoral rotation in plain radiograph. Methods: Eighteen pairs of cadaveric femurs from Chinese individuals were used in this study. For each femur, radiographs were taken in the following positions with reference to the anatomical transepicondylar axis: neutral position; 5°, 10°, 15°, and 20° internal rotation; and 5°, 10°, 15°, and 20° external rotation. Lesser-trochanter index, which was defined as the width of lesser trochanter divided by the remaining width of the proximal femur, measured at the level of its most prominent point, which was perpendicular to the anatomical axis of the proximal femur, was obtained on a Picture Archiving Communication System workstation in every radiograph. Statistical analyses were performed by using a statistical software R (R language, version 2.12.0). Results: The lesser-trochanter index showed positive correlation with increasing external rotation of femur: correlation coefficient = 0.75 (p<0.00001). Analysis-of-variance test showed that the lesser-trochanter indexes of Group 1 (20° and 15° internal rotation), Group 2 (10° internal rotation to 10° external rotation), and Group 3 (15° and 20° external rotation) had statistically significant differences (p<0.00001). Receiver operating characteristic curves were used to determine the cutoff value of lesser-trochanter index to distinguish the three groups. By using the lower cutoff value as 0.17, we can distinguish Group 2 from Group 1 with a sensitivity of 0.85 and a specificity of 0.65. By using the upper cutoff value as 0.28, we can distinguish Group 2 from Group 3 with a sensitivity of 0.80 and a specificity of 0.73. Conclusion: The lesser-trochanter index can be used as a method to assess the rotational alignment of femur in plain radiograph. It is simple, objective, not affected by the factor of magnification, and can be applied to both long and short films. © 2012.link_to_subscribed_fulltex

Axial alignment of the lower extremity in Chinese adults

Background: The restoration of normal axial alignment of the lower extremity is important to surgeons who perform reconstructive surgery of the knee. However, data on the normal alignment of the lower extremity in Chinese adults are not available. Methods: The axial alignment of the lower extremity in twenty-five adult male and twenty-five adult female volunteers of southern Chinese origin was measured on weight-bearing radiographs of the entire lower limb. The mean age was twenty-four years for the male volunteers and twenty-three years for the female volunteers. The results were compared with those of two similar studies of white volunteers in the United States. Results: The medial inclination of the tibial plateau in the Chinese subjects (mean and standard deviation, 5.4 ± 2.5 degrees for women and 4.9 ± 2.3 degrees for men) was greater than the commonly reported 3 degrees. The extremities of the Chinese women were found to have a mean of 2.2 ± 2.5 degrees of varus alignment, and those of the Chinese men had a mean of 2.2 ± 2.7 degrees of varus alignment. Conclusions: Compared with the white subjects described in the studies by Moreland et al. and Hsu et al., the Chinese subjects had significantly larger medial inclination of the knee joint (knee-joint obliquity) (p < 0.005) and the female Chinese subjects had significantly more varus alignment of the lower extremity (p < 0.025). Clinical Relevance: Five degrees of external rotation of the femoral component, instead of the commonly reported 3 degrees, may be required to obtain a rectangular flexion gap in total knee arthroplasty in Chinese patients. The racial difference in the knee-joint obliquity may contribute to the racial difference in the ratio of knee osteoarthritis to hip osteoarthritis. Additional studies are necessary to confirm this relationship.published_or_final_versio

Use of strontium-enriched bioactive bone cement in enhancing tendon osteointegration in a rabbit anterior cruciate ligament reconstruction model

Conference Theme: Defying the Aging Spine: Our Mission ContinuesConcurrent Free Papers 5 - Sports: no. 5.17Introduction: It was hypothesised that strontium led to accelerated healing of strontium-enriched calcium phosphate cement (Sr-CPC)–treated soft tissue tendon graft within the bone tunnel in anterior cruciate ligament (ACL) reconstruction. This hypothesis was tested in a rabbit ACL reconstruction model using Achilles tendon allograft. Methods: A total of 30 bilateral ACL reconstructions were performed in 15 rabbits. The graft on the tested limb was treated with Sr-CPC, while that on the contralateral limb was treated with CPC. Three were sacrificed for histomorphometric analysis respectively at 3, 6, 9, 12, and 24 weeks after the index operation. Histomorphometric analysis of the healing of graft was done by 2 independent observers in 42 histological zones per animal using a scoring system of 0 to 9. The data were analysed by Mann-Whitney U test. Results: Accelerated healing of the graft within bone tunnel was noted in the strontium-treated limb at 3, 6, 9, and 12 weeks after the operation (p < 0.001) when compared with the CPC-treated limb. Complete healing of the graft by Sharpey’s fibre formation at 9 weeks and early evidence of remodelling into normal ACL insertion site at 12 weeks were noted in the SrCPC group. The healing of the graft in the CPC-treated limb was noted 3 to 6 weeks slower than the Sr-CPC group. Conclusion: Strontium is the main contributing factor leading to accelerated healing of Sr-CPC–treated soft tissue tendon graft in a rabbit ACL reconstruction model.postprin

Use of strontium-enriched bioactive bone cement in enhancing tendon osteointegration in a rabbit anterior cruciate ligament reconstruction model

Conference Theme: Defying the Aging Spine: Our Mission ContinuesConcurrent Free Papers 5 - Sports: no. 5.17Introduction: It was hypothesised that strontium led to accelerated healing of strontium-enriched calcium phosphate cement (Sr-CPC)–treated soft tissue tendon graft within the bone tunnel in anterior cruciate ligament (ACL) reconstruction. This hypothesis was tested in a rabbit ACL reconstruction model using Achilles tendon allograft. Methods: A total of 30 bilateral ACL reconstructions were performed in 15 rabbits. The graft on the tested limb was treated with Sr-CPC, while that on the contralateral limb was treated with CPC. Three were sacrificed for histomorphometric analysis respectively at 3, 6, 9, 12, and 24 weeks after the index operation. Histomorphometric analysis of the healing of graft was done by 2 independent observers in 42 histological zones per animal using a scoring system of 0 to 9. The data were analysed by Mann-Whitney U test. Results: Accelerated healing of the graft within bone tunnel was noted in the strontium-treated limb at 3, 6, 9, and 12 weeks after the operation (p < 0.001) when compared with the CPC-treated limb. Complete healing of the graft by Sharpey’s fibre formation at 9 weeks and early evidence of remodelling into normal ACL insertion site at 12 weeks were noted in the SrCPC group. The healing of the graft in the CPC-treated limb was noted 3 to 6 weeks slower than the Sr-CPC group. Conclusion: Strontium is the main contributing factor leading to accelerated healing of Sr-CPC–treated soft tissue tendon graft in a rabbit ACL reconstruction model.postprin

Comparison of fatty-acid-binding protein 4 and adiponectin levels in infrapatellar fat pad and subcutaneous adipose tissue, synovial fluid and plasma in subjects with knee osteoarthritis

Conference Theme: Defying the Aging Spine: Our Mission ContinuesConcurrent Free Papers 2 - Basic Science/General Orthopaedics: no. 2.8Introduction: It was recently reported that inflammation is involved in the pathogenesis of osteoarthritis (OA). Fattyacid-binding protein 4 (FABP4) and adiponectin are both adipocyte-derived cytokines closely related with inflammation pathways. The FABP4 exhibits a pro-inflammatory property while adiponectin shows anti-inflammatory effect. The study aimed to assess the expression of FABP4 and adiponectin in paired blood and synovial fluid from OA patients, and to examine whether the infrapatellar fat pad (IPFP) from OA subjects would release FABP4 and adiponectin similar to that of donor-matched subcutaneous adipose tissue (ScAT). Materials and Methods: Plasma, synovial fluid, ScAT, and IPFP of 20 OA patients (4 males and 16 females) were collected during total knee arthroplasty. Levels of FABP4 and adiponectin were measured in plasma, synovial fluid, and fat conditioned media using ELISA (AIS, HKU). Results: Levels of FABP4 were significantly higher in IPFP media than ScAT (p = 0.015), while the same were significantly higher in synovial fluid than in plasma (p < 0.001). There were no significant differences of adiponectin levels between IPFP and ScAT media (p = 0.737). Plasma levels of adiponectin were significantly higher than synovial fluid (p < 0.001). Discussion and Conclusion: The OA patients exhibit an inflammatory state in local environment (IPFP and synovial fluid) compared with systemic environment (ScAT and plasma). The IPFP may play a key role in OA inflammation and may be an important resource of inflammatory mediators in synovial fluid.postprin

Effectiveness of an integrated adventure-based training and health education program in promoting regular physical activity among childhood cancer survivors

Background: There is growing concern about declining levels of physical activity in childhood cancer survivors. This study aimed to examine the effectiveness of an integrated adventure-based training and health education program in promoting changes in exercise behavior and enhancing the physical activity levels, self-efficacy, and quality of life of Hong Kong Chinese childhood cancer survivors. Methods: A randomized controlled trial, two-group pretest and repeated post-test, between-subjects design was conducted to 71 childhood cancer survivors (9- to 16-year-olds). Participants in the experimental group joined a 4-day integrated adventure-based training and health education program. Control group participants received the same amount of time and attention as the experimental group but not in such a way as to have any specific effect on the outcome measures. Participants' exercise behavior changes, levels of physical activity, self-efficacy, and quality of life were assessed at the time of recruitment, 3, 6, and 9 months after starting the intervention. Results: Participants in the experimental group reported statistically significant differences in physical activity stages of change (p < 0.001), higher levels of physical activity (p < 0.001) and self-efficacy (p = 0.04) than those in the control group. Besides, there were statistically significant mean differences (p < 0.001) in physical activity levels (-2.6), self-efficacy (-2.0), and quality of life (-4.3) of participants in the experimental group from baseline to 9 months after starting the intervention. Conclusions: The integrated adventure-based training and health education program was found to be effective in promoting regular physical activity among childhood cancer survivors. Copyright © 2013 John Wiley & Sons, Ltd.postprin

Surgical debridement with prostheses retention for the treatment of acute periprosthetic infections following total knee arthroplasty

Free Paper Presentation Session 6 – Adult Joint Reconstruction: no. 6.3INTRODUCTION: Periprosthetic infection after total knee arthroplasty (TKA) is difficult to treat. Surgical debridement with retention of prostheses is one of the valid methods ...postprin

Case series of Jehovah's witnesses having Total Knee Arthroplasty in Hong Kong

Electronic Poster Presentations: P48INTRODUCTION: Total knee arthroplasty (TKA) is challenging in Jehovah’s Witnesses (JW), as they do not accept transfusions. We report our experiences with a series of TKAs in JW in our ...postprin