Kinematical alignment during total knee arthroplasty is an emerging process, and draws more and more attentions from scholars. Knee joint is close to normal joint after TKA through kinematical alighment, which has good clinical results and functional scores, and not increase failure probility. Thus, it may increase joint stress of patella-femur joint, lead to patellar maltracking and increase abrasion. The paper summarized defination and basical principle, operative method, clinical outcomes and deficiency of kinematical alignment during total knee arthroplasty, in order to choose a better way for kinematical alignment during total knee arthroplasty.
Arthroplasty, Replacement, Knee ; methods ; Biomechanical Phenomena ; Humans

In total hip arthroplasty (THA), the accurate positioning of implants is the key to achieve a good clinical outcome. Computer-assisted orthopaedic surgery (CAOS) has been developed for more accurate positioning of implants during the THA. There are passive, semi-active, and active systems in CAOS for THA. Navigation is a passive system that only provides information and guidance to the surgeon. There are 3 types of navigation: imageless navigation, computed tomography (CT)-based navigation, and fluoroscopy-based navigation. In imageless navigation system, a new method of registration without the need to register the anterior pelvic plane was introduced. CT-based navigation can be efficiently used for pelvic plane reference, the functional pelvic plane in supine which adjusts anterior pelvic plane sagittal tilt for targeting the cup orientation. Robot-assisted system can be either active or semi-active. The active robotic system performs the preparation for implant positioning as programmed preoperatively. It has been used for only femoral implant cavity preparation. Recently, program for cup positioning was additionally developed. Alternatively, for ease of surgeon acceptance, semi-active robot systems are developed. It was initially applied only for cup positioning. However, with the development of enhanced femoral workflows, this system can now be used to position both cup and stem. Though there have been substantial advancements in computer-assisted THA, its use can still be controversial at present due to the steep learning curve, intraoperative technical issues, high cost and etc. However, in the future, CAOS will certainly enable the surgeon to operate more accurately and lead to improved outcomes in THA as the technology continues to evolve rapidly.
Arthroplasty ; Arthroplasty, Replacement, Hip* ; Hip ; Learning Curve ; Methods

Although stems improve initial mechanical stability in revision total knee arthroplasty (TKA), ideal indications, proper lengths and diameters, and appropriate fixation methods remain controversial. The topics of the present article include the indications, selection of lengths and diameters, and fixation methods of stems in revision TKA. The use of a stem in revision TKA can protect the juxta-articular bone. A stem cannot be a substitute for optimal component fixation; it plays an adjunctive role in transferring the loads from the compromised metaphysis to the stronger diaphysis. Proper bone surface preparation and appropriate use of the stem based on a great store of knowledge are required to support the stemmed components effectively in revision TKA. The balance between overshielding and overloading the juxta-articular bone would provide excellent structural protection. The stem length and diameter should be tailored according to patients’ anatomical characteristics and determined fixation strategy. There are two traditional methods of stem fixation including the total cementation technique and the hybrid technique with a cementless press-fit stem. Selection of a cementation technique should be based on thorough consideration of advantages and disadvantages of each technique.
Arthroplasty ; Arthroplasty, Replacement, Knee ; Cementation ; Diaphyses ; Knee ; Methods

OBJECTIVETo systematically review the effectiveness of minimally invasive total hip arthroplasty (MIS-THA) versus traditional total hip arthroplasty (THA) in patients with hip diseases.

METHODSThrough a method of combining Free words and keywords,we searched databases including PubMed,The Cochrane Library, EMbase,Web of Science, CBM , CNKI and Wanfang Data for randomized controlled trials (RCTs) on the comparison between MIS-THA and THA for hip disease from inception to June, 2014. Two reviewers independently screened literatures according to the inclusion and exclusion criteria, extracted data and assessed the quality of the included studies according to the "bias risk assessment" tool recommended by Cochrane Handbook 5.0 for Systematic Reviews. Then, meta-analysis was performed using RevMan 5.3 software.

RESULTSThirteen RCTs involving 1 213 cases of surgeries and total 1 284 hips (MIS-THA: n = 631; THA: n = 653) were identified. The results of meta-analysis showed that statistically significant differences were found in Harris hip score on the 3rd month after operation [MD = 8.37, 95% CI (6.02,10.72)], Hematocrit [MD = 0.02, 95% CI (0.01, 0.03)] and Hemoglobin [MD = 0.50, 95% CI (0.16, 0.85)] at the 48th hour after operation, changed value of femoral offset [MD = 0.30, 95% CI (0.04, 0.56)] between two groups. In the change value of femoral offset, THA was better than MIS-THA; There were no statistically significant differences between two groups in Harris hip score at 1st year after operation [MD = 3.26, 95% CI (-3.25, 9.76)], WOMAC score [MD = -0.53, 95% CI (-3.67, 2.60)] and Oxford score [MD = 1.34, 95% CI (-3.46, 6.13)] at the 6th week after operation, Hematocrit at the 8th hour after operation [MD = -0.01, 95% CI (-0.02, 0.00)], the incidence of hip varus [RR = 0.82, 95% CI (0.45,1.52)] and dislocation [RR = 1.40, 95% CI (0.48, 4.12)].

CONCLUSIONTHA brings less trauma, less hemorrhage and better early clinical outcome compared with MIS-THA, but the difference of the complication rates between the two groups is similar.

To contrast the methodology of measuring cup placement precision utilizing Mimics and Matlab programming, based on clinical CT images of primary THA cases with computer assisted navigated surgery (CANS) and with the traditional manual method (MANS). The method was applied and analyzed to measure cup anteversion, cup abduction of 50 clinical cases with CANS and MANSThe results show that, cup placement precision differences exits between primary THA cases with CANS and MANS; more cases with CANS are within the safe zone contrasting MANS, and there was less variation and less placement error in CANS cases. CANS can improve cup placement precision and reduce the chance of dislocation efficiently.
Arthroplasty, Replacement, Hip ; instrumentation ; methods ; Humans ; Surgery, Computer-Assisted ; methods

How to remove the well fixed cement or cementless prosthesis and get a completely distal cement removal in the rTHR are critical to the outcome of revision. Because of higher rate of union, excellent intraoperative exposure, and adjustment of abductor tension, ETO has been widely applied to rTHR and complicated primary THR by foreign scholars. Furthermore, this technology has wide indications, very few contraindications, high cure rates,and low complications rate. ETO turns out to be a safe and effective revision technology. In the article, the indication, contraindication, complications and advantages of this technique were reviewed.
Arthroplasty, Replacement, Hip ; methods ; Humans ; Osteotomy ; adverse effects ; methods

Arthroplasty, Replacement ; methods ; Clinical Trials as Topic ; Humans ; Joint Prosthesis

Arthroplasty, Replacement, Hip ; methods ; Bone Transplantation ; Femur ; surgery ; Humans

Arthroplasty, Replacement, Knee ; adverse effects ; methods ; Humans ; Postoperative Complications ; therapy

BACKGROUNDThe acetabular teardrop is often used to guide acetabular component placement in total hip arthroplasty (THA). Placing the lower acetabular component aspect at the same level as the lower teardrop edge was assumed to restore the hip center of rotation. Here we radiographically analyzed the relationship between cup center and normal contralateral acetabulum center height on unilateral THA using this placement method.

METHODSA total of 106 unilateral THA cases with normal contralateral acetabula were reviewed and the vertical and horizontal distances in relation to the lower acetabular teardrop edge from both hip joint centers, cup inclination, and anteversion were measured radiographically. The paired t-test was used to compare left and right hip center heights. Scatter plots and Pearson's correlation coefficients were used to evaluate differences in hip center heights, cup anteversion, inclination angles, and medialized cup center distance compared to the contralateral hip joint.

RESULTSCup center height was significantly greater (P < 0.01) than contralateral hip joint center height (93.4% in the 0-5 mm range, 6.6% >5 mm). There was a weak correlation between hip center height difference and inclination (r = 0.376, P < 0.01) and between difference and anteversion (r = 0.310, P < 0.01) but no correlation between difference and outer cup diameter (r = 0.184, P = 0.058) or difference and medialized cup center distance (r = -0.098, P = 0.318).

CONCLUSIONSAlthough this method did not exactly replicate anatomic hip center height, the clinical significance of cup center height and anatomic hip center height differences is negligible. This acetabular component placement method has high simplicity, reliability, and stability.