It has been postulated that the larger femoral head size may be associated with reduced risk of dislocation after total hip arthroplasty(THA). However, Dislocation after THA has a multifactorial etiology with variables such as femoral head size, type of cup, stem and surgical approach. The objectives of this study is to evaluate the association between femoral head component head size, surgical approach, surgeon's experience and the rate of dislocation after THA.Introduction
Objectives
Corrosion at the modular junction of the femoral component in total hip arthroplasty (THA) was considered as a cause of adverse local tissue reaction in recent years. We reported three adverse local tissue reaction cases after total hip arthroplasty using the same modular neck stem in this study. We have been essentially using the same titanium modular neck stem system and the same combination bearing surface of 26mm cobalt chromium (CoCr) head and highly cross linked polyethylene line for primary total hip arthroplasty since November 2009. Three female showed adverse local tissue reaction and had additional surgical treatment after the THA.Introduction
Materials and Methods
Neck and cup impingement resulted in producing larger amount of wear and risk for dislocation after total hip arthroplasty. DDH had more complex to adjust combined cup and femoral neck anteversion during surgery. Dislocation is the second most prevalent complication in total hip replacement with a 2–4% incidence. These resulted in significant financial burden to health care system. Sixteen million US dollars or more cost had in Japanese health insurance system every year. Purpose of this study was to evaluate neck-cup impingement with neck changeable M/L taper Kinectiv stem for DDH patients. Single surgeon's series were analyzed neck cup impingement of 1152 primary total hip surgeries with DDH. 269 hips in men, surgical approach were 754 mini-one antero-lateral, 284 mini- Watson-Jones, and 114 Hardinge. Acetabular cups were seated 20 degrees anteversion. Kinectiv Stem (Zimmer, Warsaw, IN) was inserted manually with standard technique. Femoral head selection was performed 26mm CoCr basis. 32mm were used for 75 years old or more, and 36mm were 80 years or older. First trial was performed with straight type of neck and 26mm femoral head based on preoperative templating. At neck and head trial to evaluated antero-superior impingement with “flex+add.+IR” and postero-inferior impingement with “ext.+add.+ER”. If the neck and cup impingement occurred even if no dislocation, necks were replaced counter version or larger offset.Introduction
Materials & Methods
It is important to measure 2-dimensional (2D) polyethylene wear in total hip arthroplasty (THA) accurately in order to estimate value of wear performance. However, wear vector direction is usually defined in a coordinate system specific manner, which sometimes leads to confusion and makes it difficult to compare measures between techniques. We systematically evaluated the influence of four different coordinate system definitions for the measurement of 2D wear in acetabular cups form radiographs. We performed 2D wear measurement of 152 hips that underwent THA using a 26mm CoCr femoral head with the same design of cementless acetabular shell between September 2003 and March 2005. All hips received either a CPE liner (76 hips, gamma sterilized at 25 kGy) or a XLPE liner (76hips, 10Mrad e-beam irradiation, EtO sterilized) randomly during the surgery. The average follow-up was 81.6±8.2 months. Supine AP radiographs obtained postoperatively at 6 months and final follow-up were assessed for each femoral head penetration and angle using Roman v1.70 software (
#1; the line tangent to both ischiums was defined as 0 degrees, with wear directed medially defined as positive and wear detected laterally defined as negative. #2; wear directed toward the liner (Zone 1 and Zone 2) defined as positive and away from it as negative (Zone 3 and Zone 4). #3; wear vector magnitude angle ranging between 0 and 360, starting from the medial part of the line (x axis). #4; wear vector between 0 and 180, directed towards the liner, was identical with coordinate #3. The vector between 180 and 360, directed away from the liner, was analyzed into the positive cosine magnitude. (Modified #3)Introduction
Materials and Methods
Highly cross-linked polyethylene (XLPE) was introduced into clinical practice to decrease acetabular cup wear in total hip arthroplasty (THA) based upon extremely low wear rates in vitro. Numerous short-term clinical studies using XLPE cups have shown promising improvements in wear performance. In this study we evaluated in vivo wear performance of XLPE cups compared to conventional PE (CPE) cups in primary THA at a minimum five years follow-up. Between October 2003 and March 2005, 114 hips were randomized to receive either a CPE cup or a XLPE cup with primary THA. A single experienced surgeon performed all cases at the same hospital. All hips received a CoCr femoral head and a cementless acetabular shell (Trilogy, Zimmer, Warsaw). One-hundred three cases received cementless femoral stems and eleven stems were cemented. Forty-six hips received a 26 mm head size CPE cup (gamma sterilized at 25 kGy), and 68 hips received XLPE cups (10 Mrad e-beam irradiation, EtO sterilized) in 26 mm (47 hips), 28 mm (11 hips) and 32 mm (10 hips) head sizes. The mean age in the XLPE and CPE groups was 57 ± 8 and 62 ± 8, respectively (p < 0.05). Mean follow up was 70 months (range, 60 to 91 months). Supine AP radiographs were obtained postoperatively at 2, 6, 9, 12, 18, 24, 36, 48, and 60 months, and at final follow-up. Each radiograph was assessed for femoral head penetration using Roman v1.70 software (Introduction:
Materials and Methods:
Crowe IV complete dislocated hips were thought to be difficult for primary THA. Correction for leg length discrepancy associated with nerve palsy or tough to reduction during surgery. Purpose of this study was to evaluate 3.5cm total leg length correction for any type of Crowe IV patients setting in anatomical positioning of acetabular cup with femoral shortening osteotomy. 24 hips were evaluated averaged 28 months after primary THA. Correction length of center of rotation, amount of femoral shortening, Harris hip score, and abductor muscle power recovery with MicroFet 2 caluculator. Bilateral cases were preformed with 6 months interval. Length of femur and tibia compared to contralateral normal side were evaluated from plain radiograms.Purpose
Materials & Methods
Dysplastic acetabulum (DDH) have some difficulty even if with conventional approach of THA. Indication or contraindication is not clear with MIS THA. The purpose of this study was to evaluate complications with mini antero-lateral approach for DDH patients. 1523 DDH hips were evaluated. Follow-up periods were averaged 36 mos. (24–74). 612 were Crowe I, 628 of II, and 283 of III. Crowe IV hips were contra-indicated. Leg length discrepancy (LLD) before and after surgery, OR time, complications during and after surgery, and length of hospital stay were evaluated.Purpose
Materials & Methods
To determine the effect of early recovery with 2 different MIS THA for patients with dysplastic hip because of relatively severe muscle weakness before surgery. MIS THA (248 MIS A/L, 96 2-incision) were performed with single surgeon from 2002. Averaged age was 61 years old. Abductor muscle power and VAS score were analyzed preop, 3, 5 7, 14 days, 2, 6 and 12 months after surgery. Patients were prone position and MicroFET machine (HOGGAN Inc. USA) were used for this analysis. All analysis were performed with single observer (physical therapist).Purpose
Materials & Methods
