Recently, short shaped stem becomes popular in total hip arthroplasty (THA). Advantages of the short stem are preserving femoral bone stock, thought to be less thigh pain, suitable for minimally invasive THA. However, bony reaction around the short stem has not been well known. The purpose of this study was to compare the two years difference of radiographic change around the standard tapered round stem with the shorter tapered round stem. Evaluation was performed in 96 patients (100 joints) who underwent primary THA. Standard tapered round stem (Bicontact D stem) was used in 44 patients from January 2011 to May 2013. Shorter stem (Bicontact E stem) was used in 56 patients from May 2015 to March 2016. The proximal shapes of these two stems are almost the same curvature. The mean age at surgery was 64 years. The mean BMI at surgery was 24.0 kg/m2. Eighty-six patients had osteoarthrosis and 10 patients had osteonecrosis. Evaluation was performed 2 years after surgery with standard AP radiographs. The OrthoPilot imageless navigation system was used during surgery. Evaluation of the stem fixation, stress shielding, and cortical hypertrophy were carried out.INTRODUCTION
MATERIALS AND METHODS
Long term results of Total Hip Arthroplasty (THA) are affected by wear of articulation. Ceramic on ceramic articulation have been used especially for young patients because of its low wear and bio-inert property. However, because of its hardness, it is concerned that ceramic fracture, chipping, or squeaking might happen with ceramic on ceramic articulation. The purpose of this study was to investigate over 10-years clinical and radiographic results of ceramic bearing cementless THA.Introduction
Objective
Recently, the short stem has become popular in total hip arthroplasty (THA). The advantages of the short stem are that it preserves femoral bone stock, possibly results in less thigh pain, and is suitable for minimally invasive THA. However, because of the short stem, malposition may happen during surgery. The purpose of this study was to compare the stem alignment, which was measured by CT, between the standard tapered round stem and the shorter tapered round stem. CT evaluation was performed in 28 patients (29 joints) who underwent primary THA. The standard tapered round stem (Bicontact D stem) was used in 13 patients. The shorter stem (Bicontact E stem) was used in 16 patients (17 joints). The proximal shapes of these two stems have almost the tame curvature. The mean age at surgery was 68 years. The mean BMI at surgery was 23.3 kg/m2. Eighteen patients had osteoarthrosis, 3 patients had osteonecrosis, and 1 patient had femoral neck fracture. All surgeries were performed in the supine position with the direct anterior approach. The OrthoPilot imageless navigation system was used during surgery. Evaluation of the stem antetorsion angle (AA), flexion angle (FA), and varus angle (VA) were carried out.INTRODUCTION
MATERIALS AND METHODS
The decreased bone mass or local osteoporosis at the proximal femur is often recognized in patients of rheumatoid arthritis (RA). In total hip arthroplasty (THA), the cancellous bone will be lost when rasping technique is applied for the preparation of stem insertion. In addition, cutting or elongation for contracted muscles around the hip joint can be required to insert the stem. To avoid these problems, the non-broaching, non-rasping impaction technique for the stems was applied in THA for the patients with RA. We report clinical and radiographic results of this method. In surgery, the femoral neck was cut and prepared without using a box chisel, reamer or broaches, instead, a series of trial stems were used with the method of impaction technique. After impaction of cancellous bone with the final size of the trial stem, the stem is fixed by bone cement without taking any cement mantle. Full weight bearing was allowed for all patients from the next day of the surgery. We investigated short-term clinical and radiographic results and the incidence of complication that was related to this technique. Post-operative radiological results with the minimum follow-up of 12 months after surgery were analyzed in 31 joints (25 cases) with this technique. The mean age at the time of surgery was 66.3 years (46∼82). The mean duration after surgery was 62 months (14∼108).Introduction
Materials and Methods
Several papers have reported the efficacy of an imageless navigation system in acetabular cup orientation during total hip arthroplasty (THA). Also, an imageless navigation system is useful for recovering leg length discrepancy. However, no study has evaluated the accuracy of the stem antetorsion angle (SAA) with an imageless navigation system in THA. The purpose of this study was to evaluate the accuracy of the stem antetorsion angles, which were measured by CT with the CT-free navigation system. Also, we evaluate the factors that affect the inaccuracy. CT evaluation was performed in 60 patients (60 joints) who underwent primary THA from December 2011 to March 2014. Fifty-nine patients were female. The mean age at surgery was 67 years. The mean BMI at surgery was 24.0 kg/m2. Fifty-four patients had osteoarthrosis, 5 patients had osteonecrosis, and 1 patient had femoral neck fracture. All surgeries were performed in the supine position with the direct anterior approach. The OrthoPilot imageless navigation system was used during surgery. An Excia stem was used in 47 patients and a Bicontact stem was used in the other 13. Evaluation of SAA was carried out. Instead of SAA, the navigation indicates the rasp antetorsion angle based on the hip-knee-ankle plane during surgery. SAA based on the posterior condylar plane was measured with CT by using 3D THA plannning software. The accuracy of the imageless navigation system was evaluated by comparison of the navigation values obtained during surgery with the CT measured values. Correlations were analyzed with Pearson correlation analysis.INTRODUCTION
MATERIALS AND METHODS
Selection of an optimum thickness of polyethylene insert in total knee arthroplasty (TKA) is important for the good stability and range of motion (ROM). The purpose of this study is to investigate the amount of change of ROM as the thickness of trial insert increase. The study included 86 patients with 115 knees undergoing TKA from October 2012 to February 2014. There were 17 men and 69 women with an average age of 75±8 (58–92) years. The implants posterior stabilized knee (Scorpio NRG, Stryker) was used and all prostheses were fixed with cement. The ROM was measured by the goniometer under the general anesthesia at the time of operation in increments of 1°. Preoperative flexion angle was measured by passively flexing the patient's hip 90 degrees and allowing the weight of the leg to flex the knee joint (Lee et al 1998). Extension angle was measured by holding the heel and raising the leg by another examiner. During TKA, flexion and extension angle was measured in a similar manner when each insert trial (8, 10, 12, and 15mm) was inserted. After the wound closure and removing the draping, ROM was measured again. Statistical analysis of range of motion was performed using a paired t-test to determine significanceIntroduction
Material and Method
Planning of the stem antetorsion angle (SAA) is difficult with radiograph before THA. 3D THA planning software with CT is useful for planning the cup and the stem implantation angles before THA. However, even using the 3D planning software, we sometimes experience the different SAA during surgery compare to the planned SAA. The purpose of this study was to compare the implanted SAA with the preoperative planned SAA, which was planned by using 3D THA planning software. CT evaluation was performed in 44 patients (5 males) who underwent primary THA. The mean age at surgery was 67 years (range 26–85 years). The mean BMI at surgery was 24.1kg/m2 (15.6–31.7kg/m2). Forty-one patients had osteoarthrosis, 2 patients had osteonecrosis, and 1 patient had femoral neck fracture. All surgeries were performed in the supine position with the direct anterior approach. The OrthoPilot imageless navigation system (BBraun/Aesculap) was used during surgery. Excia stem was used in 34 patients and Bicontact stem was used in 10 patients. Planning of the surgery was performed using 3D THA planning software (ZedHip, Lexi). After surgery, SAA was measured with CT by the same 3D THA planning software. SAA was evaluated by comparison of the planned values before surgery with the CT measured values. Also, the shape of the femur and the stem were evaluated.Introduction
Materials and Methods
Imageless navigation is useful in acetabular cup orientation during total hip arthroplasty (THA). There is a limitation of accuracy in the imageless navigation system because of the registration method, that is, to palpate bony landmarks over the skin. To improve this limitation, ultrasound-based navigation was introduced for more precise registration of bony landmarks. We evaluated the accuracy of placement of the implant, which was measured by CT in 66 patients. 22 patients underwent THA with imageless navigation, and 44 patients underwent THA with ultrasound-based navigation. The accuracy was evaluated by comparison of the navigation values obtained during surgery with the CT measured values. For the 44 patients with ultrasound-based navigation system, the mean CIA was 39.6+4.1 degrees (mean+SD) and the CAA was 18.5+6.1 degrees with CT evaluation. Ultrasound-based navigation showed 39.0+3.2 degrees in CIA and 18.8+5.9 degrees in CAA during surgery. The mean absolute difference in cup inclination angle (CIA) between ultrasound-based navigation and CT was 2.4+2.1 degrees (range 0.1–9.2 degrees). The mean absolute difference in cup anteversion angle (CAA) between navigation and CT was 2.2+2.7 degrees (0.04–12.2 degrees). The rasp ante-torsion angle was 28.6+10.0 degrees in the ultrasound-based navigation system. The mean SAA was 28.8+9.3 degrees in CT. Strong correlation was found between the rasp ante-torsion angle and SAA (r=0.858). The mean absolute difference between the rasp ante-torsion angle and SAA was 4.3+3.6 degrees (0.2-17.2 degrees). For the 22 patients with imageless navigation system, the mean absolute difference between imageless navigation and CT in CIA, CAA, and SAA were 2.5+1.8 degrees (0.1–5.8 degrees), 5.4+3.8 degrees (0.1–17.2 degrees), and 5.2+3.0 degrees (1.1-12 degrees) respectively. The thickness of subcutaneous tissue at the pubic symphysis was correlated to the difference in CAA between the imageless navigation and CT (r=0.456). Ultrasound-based navigation showed higher accuracy in CAA compare to imageless navigation. Moreover, ultrasound-based navigation showed almost the same accuracy of placement of the implant compare to the reported accuracy with CT-based navigation. Ultrasound-based navigation system improved the limitation of accuracy in the imageless navigation system.
The efficacy of an imageless navigation system in acetabular cup orientation during total hip arthroplasty (THA) is well known. We evaluated the accuracy of placement of the cup and stem and leg extension length with the imageless navigation system. Radiographic evaluation was performed in 69 consecutive patients (75 joints) who underwent primary THA from January 2009 to December 2010. Evaluation of the cup inclination angle (CI), cup anteversion angle (CA), leg extension length (L) and stem anteversion angle (SA) was carried out. SA was evaluated in 21 patients who underwent CT scan after surgery. The accuracy of imageless navigation system was evaluated by comparison of the navigation values obtained during surgery with the radiographic or CT measured values. Good correlation was found between the navigation values and the radiographic or CT measured values in CI (P<0.001, r2 = 0.579), CA (P<0.001, r2 = 0.607), L (P<0.001, r2 = 0.775), and SA (P<0.001, r2 = 0.834). The mean absolute difference between navigation and radiograph or CT was 3.3 degrees (range 0.1 to 9.9 degrees) in CI, 4.6 degrees (0.1 to 11.4 degrees) in CA, 3.2mm (0.7 to 8.3) in L, and 3.6 degrees (0.1 to 10 degrees) in SA. The results of this study demonstrated that imageless navigation shows good accuracy not only in cup implantation angle but also in leg extension length and in stem anteversion angle according to radiographic and CT evaluation. We conclude that imageless navigation is a useful tool for performing accurate surgery for THA.
