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

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

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.

BACKGROUND: Computer-assisted orthopaedic surgery (CAOS) improves accuracy and reduces outliers in total knee arthroplasty (TKA). However, during the evaluation of CAOS systems, the error generated by the guidance system (hardware and software) has been generally overlooked. Limited information is available on the accuracy and precision of specific CAOS systems with regard to intraoperative final resection measurements. The purpose of this study was to assess the accuracy and precision of a next generation CAOS system and investigate the impact of extra-articular deformity on the system-level errors generated during intraoperative resection measurement. METHODS: TKA surgeries were performed on twenty-eight artificial knee inserts with various types of extra-articular deformity (12 neutral, 12 varus, and 4 valgus). Surgical resection parameters (resection depths and alignment angles) were compared between postoperative three-dimensional (3D) scan-based measurements and intraoperative CAOS measurements. Using the 3D scan-based measurements as control, the accuracy (mean error) and precision (associated standard deviation) of the CAOS system were assessed. The impact of extra-articular deformity on the CAOS system measurement errors was also investigated. RESULTS: The pooled mean unsigned errors generated by the CAOS system were equal or less than 0.61 mm and 0.64degrees for resection depths and alignment angles, respectively. No clinically meaningful biases were found in the measurements of resection depths (< 0.5 mm) and alignment angles (< 0.5degrees). Extra-articular deformity did not show significant effect on the measurement errors generated by the CAOS system investigated. CONCLUSIONS: This study presented a set of methodology and workflow to assess the system-level accuracy and precision of CAOS systems. The data demonstrated that the CAOS system investigated can offer accurate and precise intraoperative measurements of TKA resection parameters, regardless of the presence of extra-articular deformity in the knee.
Arthroplasty, Replacement, Knee/*methods ; Reproducibility of Results ; *Surgery, Computer-Assisted

Computer assisted surgery (CAS) was used to improve the positioning of implants during total knee arthroplasty (TKA). Most studies have reported that computer assisted navigation reduced the outliers of alignment and component malpositioning. However, additional sophisticated studies are necessary to determine if the improvement of alignment will improve long-term clinical results and increase the survival rate of the implant. Knowledge of CAS-TKA technology and understanding the advantages and limitations of navigation are crucial to the successful application of the CAS technique in TKA. In this article, we review the components of navigation, classification of the system, surgical method, potential error, clinical results, advantages, and disadvantages.
Arthroplasty, Replacement, Knee/*methods ; Humans ; *Surgery, Computer-Assisted

PURPOSE: We devised an intraoperatively identifiable mechanical axis (IIMA) as a reference of alignment in total knee arthroplasty (TKA). MATERIALS AND METHODS: Between February 2010 and January 2011, primary TKAs were consecutively performed on 672 patients (1007 knees) using an IIMA as a reference in the coronal plane. RESULTS: The alignment of the lower extremity improved from a mean of 11.4+/-6.7degrees (-10.3-34.4degrees) of varus preop. to 0.7+/-3.5degrees (-5.2-8.6degrees) immediately after surgery. Mean alignment of the femoral component in the coronal plane was 89.3+/-2.3degrees (83.4-97.2degrees) postop. and mean alignment of the tibial component was 90.4+/-2.2degrees (85.1-94.2degrees) postop. CONCLUSION: This study showed that IIMA could be of considerable value as a new guider of alignment that is easily accessible and highly effective during total knee arthroplasty.
Arthroplasty, Replacement, Knee/*methods ; Femur/surgery ; Humans ; Tibia/surgery

BACKGROUNDControversy still exists regarding whether medial parapatellar approach (MP) or midvastus approach (MV) is preferable in total knee arthroplasty (TKA) up to now. The aim of this meta-analysis was to compare the clinical and radiological outcomes following the MV or MP for TKA.

METHODSA comprehensive search of unrestricted-language literature of all studies comparing MP with MV was conducted through the electronic literature databases of PubMed, EMBASE, Cochrane Library, CNKI, VIP, and WANFANG. Retrieval time was from the time when databases were built to October 2013. Manual search of relevant trials, reviews, and related articles was also performed. Outcomes of interest included postoperative knee extensor and flexor function, postoperative pain, patella tilt, and complications. Relative risk (RR) and weighted mean differences (WMD) from each trial were pooled using random-effects or fixed-effects model depending on the heterogeneity of the included studies. A subgroup analysis or a sensitivity analysis was conducted to explore the potential source of heterogeneity when necessary.

RESULTSTwenty-one randomized controlled trials (RCTs) comprising 1 188 patients (1 450 knees) were eligible. Our results showed that MV was associated with better early postoperative extension (WMD = -1.26, 95% CI -2.36 to -0.16, P = 0.02) and flexion (WMD = 10.13, 95% CI 5.36 to 14.90, P < 0.01), less postoperative pain (WMD = -0.21, 95% CI -0.34 to -0.07, P = 0.002) , and no greater risk for complications than MP. The patella tilt did not differ significantly between the two groups (WMD = -0.70, 95% CI -1.94 to 0.54, P = 0.27).

CONCLUSIONSMV may be a better approach than MP, as it improves postoperative early joint function and decreases pain. Future multi-center randomized controlled studies with large sample sizes are required to verify the current findings.