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

Orthopaedic implant technology is heavily based on the development and use of biomaterials. These are non-living materials (e.g. metals, polymers and ceramics) that are introduced into the human body as constituents of implants that fulfill or replace some important function. Examples would be prosthetic joint replacements and fracture fixation implants. For orthopaedic biomaterials to succeed in their desired functions and outcomes in the body, a number of factors need to be considered. The most obvious mechanical properties of the implants are that they need to suit their intended function, and various classes and types of biomaterials have been developed and characterised for use in different implant components depending on their demands. Less well understood but no less important are the interactions that occur between the constituent biomaterials and the living cells and tissues, both of the human host as well as pathogens such as bacteria. Biomaterials used for orthopaedic applications are generally considered to be biocompatible. However, adverse effects arising from interactions at the implant interface can result in various modes of implant failure, such as aseptic loosening and implant infection. This review paper uses the illustrative example of total hip replacement (which has been called the operation of the century) to highlight key points in the evolution of orthopaedic biomaterials. It will also examine research strategies that seek to address some of the major problems that orthopaedic implant surgery are facing today.
Absorbable Implants ; Arthroplasty, Replacement, Hip ; instrumentation ; methods ; Biocompatible Materials ; Humans ; Orthopedic Procedures ; instrumentation ; methods ; trends ; Osteoblasts

One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements have been made with regard to fixation technique and implant quality.
Arthroplasty, Replacement, Hip/*instrumentation ; *Hip Prosthesis ; Humans ; Metals ; *Prosthesis Design ; Surface Properties ; *Weight-Bearing

In order to help a surgeon to determine a proper canal filing cutting path in a hip replacement operation conveniently, this paper presents a kind of probe with combined structure. Firstly, the doctor can use this kind of combined probe to choose canal filing cutting path. Then, the doctor can use computer to guide the surgeon to file femoral cavity along the selected canal filing cutting path. Through hip replacement corpse experiments, filing effects and used time of using combined probe group and separate control group were analyzed. The experiment results showed that the methods introduced in this paper could lower the difficulty of hip replacement operations, improve the implantation of hip stem prostheses further, and reduce the incidence of surgical complications.
Arthroplasty, Replacement, Hip ; Femur ; Hip Prosthesis ; Humans ; Surgery, Computer-Assisted ; instrumentation

Arthroplasty, Replacement, Hip ; Fracture Fixation, Internal ; Hip Fractures ; surgery ; Humans ; Precision Medicine ; instrumentation ; methods ; Preoperative Period

The assistant artificial hip joint (AAHJ) is a new impermanent hip support implanted in the body. It is used for treatment of ischemic necrosis of the femoral head at the early stage. It reserves the natural femoral head, increases its containment and decreases its load, thus makes the recovery of the necrosed femoral head. The AAHJ's moving axis center is the same as that of the femoral head. Therefore, the moving range of the hip joint is very close to the normal postoperatively. The patient can walk with loading in 3 weeks after the surgical operation, and can regain his (or her) daily work and life in 2 to 3 months of the operation. The AAHJ's structure is simple and the price is cheap.
Arthroplasty, Replacement, Hip ; instrumentation ; Femur Head Necrosis ; surgery ; Hip Joint ; surgery ; Hip Prosthesis ; Humans ; Prosthesis Design ; Recovery of Function ; Treatment Outcome

In a hip replacement case when a standard hip stem is chosen, it is rough to select hip stems before operation, thus some stand-up standard hip stems should be prepared. The operation time is usually prolonged. In order to solve this problem, this paper presents a method to automatically select optimal standard hip stems by computers. Femoral anatomical data of a patient are acquired from X-ray films. Based on these anatomical data and a database of average cross-sections in proximal femurs, proximal femur of the patient can be reconstructed. This proximal femur model makes it possible to optimally select a standard hip stem. Theory analyses indicate that the method, presented in this paper, is practicable.
Arthroplasty, Replacement, Hip ; instrumentation ; Computer-Aided Design ; Hip Joint ; diagnostic imaging ; surgery ; Hip Prosthesis ; standards ; Humans ; Radiography

Various systems of computer-assisted orthopaedic surgery (CAOS) in total hip arthroplasty (THA) were reviewed. The first clinically applied system was an active robotic system (ROBODOC), which performed femoral implant cavity preparation as programmed preoperatively. Several reports on cementless THA with ROBODOC showed better stem alignment and less variance in limb-length inequality on radiographic evaluation, less incidence of pulmonary embolic events on transesophageal cardioechogram, and less stress shielding on the dual energy X-ray absorptiometry analysis than conventional manual methods. On the other hand, some studies raise issues with active systems, including a steep learning curve, muscle and nerve damage, and technical complications, such as a procedure stop due to a bone motion during cutting, requiring re-registration and registration failure. Semi-active robotic systems, such as Acrobot and Rio, were developed for ease of surgeon acceptance. The drill bit at the tip of the robotic arm is moved by a surgeon's hand, but it does not move outside of a milling path boundary, which is defined according to three-dimensional (3D) image-based preoperative planning. However, there are still few reports on THA with these semi-active systems. Thanks to the advancements in 3D sensor technology, navigation systems were developed. Navigation is a passive system, which does not perform any actions on patients. It only provides information and guidance to the surgeon who still uses conventional tools to perform the surgery. There are three types of navigation: computed tomography (CT)-based navigation, imageless navigation, and fluoro-navigation. CT-based navigation is the most accurate, but the preoperative planning on CT images takes time that increases cost and radiation exposure. Imageless navigation does not use CT images, but its accuracy depends on the technique of landmark pointing, and it does not take into account the individual uniqueness of the anatomy. Fluoroscopic navigation is good for trauma and spine surgeries, but its benefits are limited in the hip and knee reconstruction surgeries. Several studies have shown that the cup alignment with navigation is more precise than that of the conventional mechanical instruments, and that it is useful for optimizing limb length, range of motion, and stability. Recently, patient specific templates, based on CT images, have attracted attention and some early reports on cup placement, and resurfacing showed improved accuracy of the procedures. These various CAOS systems have pros and cons. Nonetheless, CAOS is a useful tool to help surgeons perform accurately what surgeons want to do in order to better achieve their clinical objectives. Thus, it is important that the surgeon fully understands what he or she should be trying to achieve in THA for each patient.
Arthroplasty, Replacement, Hip/instrumentation/*methods ; Humans ; *Robotics ; Stereotaxic Techniques ; *Surgery, Computer-Assisted

OBJECTIVETo study the efficiency of decreasing instability of large femoral head components in revision total hip arthroplasty (THA).

METHODSFrom August 2005 to December 2010, 107 patients (112 hips) with 28 mm femoral head components (28 mm group) and 46 patients (46 hips) with 36 mm femoral head components (36 mm group) in revision THA were analyzed retrospectively in order to find if the dislocation rate and Harris hip score were different between the two groups at the time of last follow-up. All the operations were performed by the first author. There were 81 male patients (85 hips) and 26 female patients (27 hips) in 28 mm group with mean age of (62±17) years (26-79 years) and 33 male patients (33 hips) and 13 female patients (13 hips) in 36 mm group with mean age of (60±16) years (31-77 years).

RESULTSThe mean follow-up period was 43.3 months (33-71 months) for 28 mm group and 26.7 months (12-37 months) for 36 mm group. There were 7 patients dislocated after revision in 28 mm group, including 2 revised with reinforcement rings (with dislocation rate 9.5%), 3 revised with impaction bone grafting technique (with dislocation rate 8.3%) and 2 revised with cementless cups (with a dislocation rate 3.6%). The dislocation rate of this group was 6.2%. While the dislocation rate of 36 mm group was 2.2%, the only dislocated patient was because of loss of gluteus medius muscle function in the index operation. If this case was excluded, the dislocation rate of 36 mm group would be 0. There was significant difference between the two groups (χ2=103.0095, P<0.01). The Harris hip score was 88±11 for 28 mm group and 89±9 for 36 mm group, there was no significant difference between the two groups (P>0.05).

CONCLUSIONThe large femoral head components can significantly decrease the instability after revision THA, which should be used in revision THA.

Adult ; Aged ; Arthroplasty, Replacement, Hip ; instrumentation ; Female ; Follow-Up Studies ; Hip Prosthesis ; Humans ; Male ; Middle Aged ; Prosthesis Failure ; Retrospective Studies

OBJECTIVETo evaluate the difference of clinical outcomes and radiological outcomes through meta-analysis on the total hip arthroplasty (THA) between hydroxyapatite(HA) coating and non-HA coating femoral stems.

METHODSWe searched the MEDLINE, Embase, Cochrane library and CBM for published randomized controlled trial (RCT) comparing HA coating and non-HA coating femoral stems in primary THA clinical outcomes with Harris hip score and incidence postoperative thigh pain, radiological outcomes with presence of endosteal condensation and radioactive line on the prothesis, heterotopic ossification. Data analysis were performed using RevMan 5.0(the Cochrane Collaboration).

RESULTSTen studies and 917 hips into our analysis, with 464 hips in HA groups and 453 hips in non-HA groups. The combined results of the meta-analysis indicated there was no statistical differences between the two groups on postoperative Harris hip score(WMD = 3.04, 95%CI:-4.47-10.54, P = 0.43) , there was statistical difference on incidence postoperative thigh pain (RR = 0.56, 95%CI:0.33-0.94, P = 0.03) . There were no significant differences between the two groups on presence of endosteal condensation (RR = 1.01, 95%CI:0.91-1.11, P = 0.91), presence of radioactive line (RR = 0.99, 95%CI:0.88-1.11, P = 0.83) and incidence of heterotopic ossification (RR = 0.97, 95%CI:0.77-1.21, P = 0.77).

CONCLUSIONSThere are no clinical and radiological benefits in the use of HA coating femoral stems in Primary THA, there is not enough evidence prove the HA can reduce the incidence postoperative thigh pain.

Arthroplasty, Replacement, Hip ; instrumentation ; Coated Materials, Biocompatible ; Durapatite ; Femur ; Hip Prosthesis ; Humans ; Randomized Controlled Trials as Topic ; Treatment Outcome