Cup In Total Hip Arthroplasty Research Articles

The dual mobility cup: what problems does it solve?

Dual mobility cups have two points of articulation, one between the shell and the polyethylene (external bearing) and one between the polyethylene and the femoral head (internal bearing). Movement occurs at the inner bearing; the outer bearing only moves at extremes of movement. Dislocation after total hip arthroplasty (THA) is a cause of much morbidity and its treatment has significant cost implications. Dual mobility cups provide an increased range of movement and a may reduce the risk of dislocation. This paper reviews the use of these cups in THA, particularly where stability is an issue. Dual mobility cups may be of benefit in primary THA in patients at a high risk of dislocation, such as those who are older with increased comorbidities and a higher American Association of Anesthesiology grade and those with a neuromuscular disease. They may be used at revision surgery where the risk of dislocation is high, such as in patients with many prior dislocations, or those with abductor deficiency. They may also be used in THA for displaced fractures of the femoral neck, which has a notoriously high rate of dislocation.

Quantitative Biomedical Imaging: Techniques and Clinical Applications.

Quantitative Biomedical Imaging: Techniques and Clinical Applications.

Dual mobility cup for prevention of early total hip arthroplasty dislocation in patients with neurological disorders

Patients with neurologic disorders are at a higher risk for hip arthroplasty dislocation. This can be attributed to hip muscle weakness, especially the abductor group. We inquired into the use of dual mobility acetabular component for the prevention of early hip dislocation in these patients. Thirty patients with documented neurological disorders and muscle weakness affecting the operated side underwent dual mobility total hip arthroplasty in the period between December 2012 and January 2014. The neurological disorders were cerebrovascular stroke, weakness due to brain tumors, Parkinsonism, old poliomyelitis, and multiple sclerosis. Twelve cases underwent primary dual mobility cup total hip arthroplasty as a treatment for proximal femoral fractures. Eighteen patients were revision to dual mobility total hip arthroplasty either due to failure of proximal femoral fracture fixation or failure of previous arthroplasty. All patients were ambulant (assisted walking) before the primary incident (either surgery or trauma). All patients were operated upon through the lateral approach. All the cups used were cemented. The mean age group of the patients was 64.6 years old. No definite postoperative infection occurred. The mean follow-up period was 13.2 months. One case died 6 months postoperative due to another cerebrovascular stroke. Functionally, all our patients could ambulate (assisted walking) postoperatively. No dislocation was recorded during the follow-up period. The dual mobility cup is effective in the prevention of early dislocation in patients with muscle weakness due to neurological disorders. Long-term follow-up is needed for the assessment of late dislocation, as well as the rate of loosening in this group of patients.

Increased migration of uncemented acetabular cups in female total hip arthroplasty patients with low systemic bone mineral density

Background and purpose — Low bone mineral density (BMD) may jeopardize the initial component stability and delay osseointegration of uncemented acetabular cups in total hip arthroplasty (THA). We measured the migration of uncemented cups in women with low or normal BMD.Patients and methods — We used radiostereometric analysis (RSA) to measure the migration of hydroxyapatite-coated titanium alloy cups with alumina-on-alumina bearings in THA of 34 female patients with a median age of 64 (41–78) years. 10 patients had normal BMD and 24 patients had low systemic BMD (T-score ≤ −1) based on dual-energy X-ray absorptiometry (DXA). Cup migration was followed with RSA for 2 years. Radiographic follow-up was done at a median of 8 (2–10) years.Results — Patients with normal BMD did not show a statistically significant cup migration after the settling period of 3 months, while patients with low BMD had a continuous proximal migration between 3 and 12 months (p = 0.03). These differences in cup migration persisted at 24 months. Based on the perceived risk of cup revision, 14 of the 24 cases were “at risk” (proximal translation of 0.2 to 1.0 mm) in the low-BMD group and 2 of the10 cases were “at risk” in the normal-BMD group (odds ratio (OR) = 8.0, 95% CI: 1.3–48). The radiographic follow-up showed no radiolucent lines or osteolysis. 2 cups have been revised for fractures of the ceramic bearings, but none for loosening.Interpretation — Low BMD contributed to cup migration beyond the settling period of 3 months, but the migrating cups appeared to osseointegrate eventually.

Intra-prosthetic dislocation of dual-mobility cups after total hip arthroplasty: potential causes from a clinical and biomechanical perspective.

Recurrent dislocation of total hip arthroplasty is a frequent indication for revision surgery. Hip joint stability depends on implant design, cup position and crucially on femoral head diameter. Due to an effective ultra-large diameter femoral head, dual-mobility cups are considered an attractive solution to prevent dislocation in unstable conditions. Although patients obviously benefit for many years in terms of mobility and pain, an increase of intra-prosthetic dislocation reports using dual-mobility cups has been recently observed. However, the failure mechanism of this implant-specific complication, which is characterized by the loss of the positive-locking between the femoral head and the mobile liner, is not yet completely understood. A comprehensive search was performed with the PubMed database and a search engine to overview this topic and to identify potential causes for this implant-specific failure from a clinical and biomechanical perspective. Peri-operative findings indicate extensive fibrosis at the large articulation as well as cup loosening as potential causes. In addition, current research has shown that the failure mechanism is affected by the surface topography of the femoral neck and in particular by the design of the mobile liner. In clinical practice it is necessary to differentiate a classic dislocation between the mobile liner and the metallic shell from an intra-prosthetic dislocation between the femoral head and the liner. Due to the increasing popularity of dual-mobility cups in total hip arthroplasty, the understanding of which implant-specific features or tissue response may increase the risk of intra-prosthetic dislocation is of major importance for reduced revision rates by using optimized surgical techniques and implant designs.

Double mobility cup total hip arthroplasty in patients at high risk for dislocation: a single-center analysis.

Double mobility cup systems (DMCS) have gained increasing acceptance, especially in patients at high risk for dislocation. The aim of this investigation was to analyze the frequency and indications of the DMCS use in our praxis and to evaluate dislocation and cup revision rates after a minimum follow-up of 2 years. All patients implanted with a DMCS from May 2008 to August 2011 were identified from our institutional database of primary and revision THA procedures. Patient demographics, including ASA score, were recorded, along with details of the surgical procedures, indications for DMCS use, and post-operative clinical course and any complications. Radiographs were analyzed for implant positioning and radiological signs of loosening. 1046 primary THA were implanted, of these 39 (4 %) primary DMCS. Indications were severe neuromuscular disease (SND) (14), hip abductor degeneration (HAD) (9), cognitive dysfunction (CD) (8) and others. 345 revision THA were performed, of these 50 (14 %) revision DMCS. Indications were recurrent dislocations (27), multiple prior hip surgeries (13), HAD (5), CD (3) and others. Overall dislocation rate was 2/89 (2 %); both in revision THA. Overall cup revision rate was 5/89 (6 %): 3 septic, 1 periprosthetic acetabular fracture, 1 "intraprosthetic dissociation". 67 patients were available for the standardized questionnaire at a median follow-up of 43 months (range 25-78). 19 patients were not available for two-year follow-up: 17 died and two were lost to follow-up. This study supports the use of DMCS constructs in primary and revision hip arthroplasty for specific high-risk patients. We continue to indicate DMCS in this patient group. We do caution against extending indications for DMCS to lower risk patient groups due to unknown issues surrounding wear and component longevity.

Performance of Porous Tantalum vs. Titanium Cup in Total Hip Arthroplasty: Randomized Trial with Minimum 10-Year Follow-Up

Porous tantalum monoblock cups have been proposed to improve survivorship of cementless primary THA. However, there are few direct comparative trials to established implants such as porous-coated titanium cups. 113 patients were randomized into two groups according to the cup: a porous tantalum monoblock cup (TM) or a porous-coated titanium monoblock cup (control). At a mean of 12 years after THA, no implants migrated in both groups. Two TM patients (4%) and 13 control patients (33%) presented with radiolucency around the cup (P<0.001). In the control group, 1 cup (2%) was revised for aseptic loosening. At 12 years post-implantation, porous tantalum monoblock cups demonstrated 100% survivorship, and significantly less radiolucency as compared to porous-coated titanium monoblock cups.

Metal-on-metal dysplasia cup total hip arthroplasty for hip osteoarthritis secondary to developmental dysplasia of the hip

This study aims to evaluate the clinical and radiological results of metal-on-metal dysplasia cup total hip arthroplasty (THA) for hip osteoarthritis secondary to developmental dysplasia of the hip (DDH). Between May 2009 and October 2011, THA was performed on 27 hips (7 Crowe type II, 9 Crowe type III, 11 Crowe type IV) of 22 patients (2 males, 20 females; mean age 43 years; range 25 to 63 years) with hip osteoarthritis secondary to DDH. All patients were evaluated clinically and radiographically. Average follow-up period was 34.2 months (range 24-53 months). While mean Harris hip score (HHS) was 43 (range 30 to 72 points) preoperatively, it was 92 (range 87 to 98 points) at final follow-up. Two patients developed sciatic nerve palsy postoperatively. Recurrent dislocation occurred in one patient one year after the operation. Mean cup inclination was 45.6° (range 42°-51°). Heterotopic ossification developed in eight patients. No patient's acetabular and femoral component migrated or subsided significantly. None of the implants was revised. Early clinical and radiological results of metal-on-metal dysplasia cup THA in DDH are satisfactory.

Cluster Hole Versus Solid Cup in Total Hip Arthroplasty: A Randomized Control Trial

Acetabular osteolysis has been linked to polyethylene debris that is generated in the hip migrating through screw holes in the acetabular component. Solid-backed acetabular components were designed to decrease this osteolysis. This prospective trial randomized 100 patients undergoing total hip arthroplasty to either a solid-backed or a cluster-hole acetabular component—all without screws. At 5years post-surgery, 34.4% of all patients had osteolytic lesions that were visible on CT. There was no significant difference in either presence or volume of the osteolytic lesions, cup migration or functional outcomes (OHS) between the groups. There may no longer be a detriment to using cluster-hole cups instead of solid cups in all hips. This would then give the surgeon the option to use screws for stability as required.

Dual mobility cups in total hip arthroplasty

Total hip arthroplasty (THA) is considered one of the most successful surgical procedures in orthopaedics. With the increase in the number of THAs performed in the world in the next decades, reducing or preventing medical and mechanical complications such as post-operative THA instability will be of paramount importance, particularly in an emerging health care environment based on quality control and patient outcome. Dual mobility acetabular component (also known as unconstrained tripolar implant) was introduced in France at the end of the 1970s as an alternative to standard sockets, to reduce the risk of THA dislocation in patients undergoing primary THA in France. Dual mobility cups have recently gained wider attention in the United States as an alternative option in the prevention and treatment of instability in both primary and revision THA and offer the benefit of increased stability without compromising clinical outcomes and implant longevity. In this article, we review the use of dual mobility cup in total hip arthroplasty in terms of its history, biomechanics, outcomes and complications based on more than 20 years of medical literature.

The use of a dual-mobility concept in total hip arthroplasty patients with spastic disorders

Total hip arthroplasty (THA) is one of the treatment options in patients with cerebral palsy (CP) with painful osteoarthritis of the hip. However, the risk of dislocation of the prosthesis is higher in patients with CP when compared with physically normal patients. In this retrospective study of ten consecutive cases, we hypothesized that the use of a dual-mobility cup could reduce this risk of dislocation combined with good functional results. From January 2008 until October 2010, eight patients (ten hips) with CP who consecutively received a THA using a dual-mobility cup were identified. At the time of surgery, the average age of the patient group was 54 years (range 43-61). Latest follow-up took place after on average 39 months (range 22-56 months). All patients or their caregivers were interviewed by telephone. They were asked if dislocation of the prosthesis had occurred. To evaluate quality of life and health in general, patients completed the SF-36 questionnaire. None of the prostheses had dislocated at the latest follow-up. Reoperation was needed in one patient after a periprosthetic fracture. Radiologic evaluation showed a mean cup inclination of 46 (range 27-58). On average, the quality of life of patients in this study was found to be limited in particular on the domains of physical health and functioning, while a fair to good score was measured at the six other different domains. The use of a dual-mobility cup in THA in patients with CP can lead to favourable results with respect to dislocation and clinical outcome.

Assessment of acetabulum anteversion aligned with the transverse acetabulum ligament: cadaveric study using image-free navigation system

The transverse acetabulum ligament (TAL) has been used as an intraoperative anatomical landmark to position the acetabulum cup in total hip arthroplasty (THA). However, the validity of the use of TAL has not been clarified. The purpose of this study was to examine the orientation of the cup component aligned with the TAL in cadaveric study. The 31 hips in 25 whole-body embalmed cadavers were examined. The donors were 12 men and 13 women. Simulated THA procedure using image-free navigation system was performed and a trial cup with a diameter of approximately 2 mm less than the size of the acetabulum were inserted and snugly fitted on the TAL through the posterior wall of acetabulum. The orientation of the cup component was measured using an image-free THA navigation system. The measured radiographic anteversion and inclination angles averaged 18.2±7.2° (range: 2.0–33.2°) and 43.5±4.2° (range: 33.1–51.0°) respectively. Based on the Lewinnek's safe zone criteria, 26 hips (80.6%) were judged to be within the. Moreover, in the analysis of the gender difference of TAL angles, the average anteversion angle was shown to be significant larger in female than male population. The TAL can be effectively used an intraoperative landmark to align the acetabulum component helping reduce the risk of dislocation after surgery. In the intraoperative judgment, a gender difference in the alignment of the TAL should be taken into consideration.

Dual-mobility cups for revision due to instability are associated with a low rate of re-revisions due to dislocation

Background and purpose Revision total hip arthroplasty (THA) due to recurrent dislocations is associated with a high risk of persistent instability. We hypothesized that the use of dual-mobility cups would reduce the risk of re-revision due to dislocation after revision THA.Patients and methods 228 THA cup revisions (in 228 patients) performed due to recurrent dislocations and employing a specific dual-mobility cup (Avantage) were identified in the Swedish Hip Arthroplasty Register. Kaplan-Meier survival analysis was performed with re-revision due to dislocation as the primary endpoint and re-revision for any reason as the secondary endpoint. Cox regression models were fitted in order to calculate the influence of various covariates on the risk of re-revision.Results 58 patients (25%) had been revised at least once prior to the index cup revision. The surgical approach at the index cup revision was lateral in 99 cases (44%) and posterior in 124 cases (56%). Median follow-up was 2 (0–6) years after the index cup revision, and by then 18 patients (8%) had been re-revised for any reason. Of these, 4 patients (2%) had been re-revised due to dislocation. Survival after 2 years with the endpoint revision of any component due to dislocation was 99% (95% CI: 97–100), and it was 93% (CI: 90–97) with the endpoint revision of any component for any reason. Risk factors for subsequent re-revision for any reason were age between 50–59 years at the time of the index cup revision (risk ratio (RR) = 5 when compared with age > 75, CI: 1–23) and previous revision surgery to the relevant joint (RR = 1.7 per previous revision, CI: 1–3).Interpretation The risk of re-revision due to dislocation after insertion of dual-mobility cups during revision THA performed for recurrent dislocations appears to be low in the short term. Since most dislocations occur early after revision THA, we believe that this device adequately addresses the problem of recurrent instability. Younger age and prior hip revision surgery are risk factors for further revision surgery. However, problems such as potentially increased liner wear and subsequent aseptic loosening may be associated with the use of such devices in the long term.

Modular cementless cup for total hip arthroplasty: results at 4-year follow-up

The aim is to perform the assessment of a modular cementless acetabular cup with a tapered internal design for all bearing couplings. In 190 unselected consecutive patients, 207 total hip arthroplasties were implanted. The implants were clinically and radiographically evaluated. Follow-up was 49.7 ± 8.1 months. The average Harris hip score improved from 55.5 ± 5.7 to 94.7 ± 3.4 (P < 0.05). All cups were well-positioned and stable. The Kaplan-Maier cumulative survivorship was 98.5 ± 0.8%. No significant differences have been noted in dividing patients according to the different liner materials (P < 0.005). The study, whose rationale is the novelty of this kind of implant, suggests the efficacy of the Delta-PF acetabular cup.

Is transverse acetabular ligament an anatomical landmark to reliably orient the cup in primary total hip arthroplasty?

Accurate positioning of the acetabular cup in primary total hip arthroplasty is critical to decrease the rate of dislocation. Inaccurate orientation of the cup is the most common error during this procedure. Target acetabular orientation is still controversial. An original study found a dislocation rate of 0.6% when the cup was aligned with the transverse acetabular ligament (TAL). TAL is a patient-specific anatomical landmark and a tool for cup orientation. Eight cadaveric pelves (14 hips included for study) were harvested in toto at our research laboratory. Anatomical versions of the TAL, labrum and horns were measured in relation to the anterior pelvic plane. A navigator sensor and an optoelectronic device (Motion Analysis™) were used. Anatomical versions of the TAL, horns and labrum averaged 1.9° (range, -8° to +13.3°), 3° (range, -12.2° to 14°), and 26.3° (range, 17.4° to 41.8°), respectively. To our knowledge, this is the first study to report the orientation of the periacetabular soft-tissues. TAL anteversion was outside the safe zone described by Lewinnek, while labrum anteversion was within this safe-zone. We discuss the reference used, Lewinnek's safe zone, and functional orientation of the implants. Lewinnek's safe-zone does not seem to be valid. The TAL seems to be a specific reference for each patient but its reliability must still be confirmed as an adequate reference for positioning the cup in total hip arthroplasty.

Analysis of factors influencing the stability of press-fit cups in total hip arthroplasty

Analysis of factors influencing the stability of press-fit cups in total hip arthroplasty

Relationship between Sacral Pelvic Incidence and Acetabular Orientation

The importance of the sacral pelvic incidence (SPI) in relation to individual variations of sagittal spinal curvature has become well-recognised. We attempted to determine the relationship between SPI and acetabular orientation. The three-dimensional coordinates of 47 homologous points were observed on 51 adult anatomical pelvises (26 female and 25 male). The reference vertical plane was Lewinnek's anterior pelvic plane. 10 angular parameters and 11 linear parameters were defined and calculated. These were expressed both in absolute value (in millimetres) and in "acetabular unit" (relative to the mean value of the right and left acetabular rays). Mean values of the parameters were calculated for all pelvises and according to gender. There were two dominant parameters: the "sacral slope" and the "V pubic angle". "Acetabular tilting" was primarily dependent on the "sacral slope" and its intermediary on the "SPI", while "acetabular anteversion" dependent on the "V pubic angle" via the "angle of prow". It is recommended that positioning of the acetabular cup in total hip arthroplasty relates to anatomical parameters, and to the global sagittal balance of the pelvi-spinal unit.

Comparison of cortical and cancellous bone remodeling of the pelvis after press-fit cup total hip arthroplasty dependent on patient and prosthesis-specific characteristics: a computed tomography-assisted osteodensitometry study in vivo

Even though periprosthetic bone loss is common after total hip arthroplasty, there is no scientific evidence whether it compromises the survival of the prosthesis. Using quantitative computed tomography-assisted osteodensitometry, we determined the pattern of periacetabular bone density (BD) changes of two different press-fit cups (54 hips) 10 days, 1 year and 3 years post-operatively. We measured cortical and cancellous BD at three points of time and evaluated the effects of patient-specific characteristics [age, gender, body mass index (BMI)], clinical function, and BD at index operation. Cancellous BD decreased in all periacetabular regions by up to -52% (p ≤ 0.001). In contrast, cortical BD above the dome of the cup remained constant while at the level of the cup it decreased by up to -17% (p ≤ 0.001). Older patients had significantly lower cortical (ventral and dorsal) and cancellous (cranial) BD values, obese patients had a higher cortical BD ventral, and patients with excellent clinical results had a higher cancellous BD ventral and dorsal to the cup. Changes in BD suggest high stress shielding of retroacetabular cancellous bone, while load is transmitted to cortical bone above the dome of the cup. Patient-specific characteristics were shown to affect BD, but long-term analysis is needed to show whether these effects are of clinical importance.

3D CT Analysis of Combined Cup and Stem Anteversion in Cases of Cup Navigation in Hip Arthroplasty

Navigation of the cup in total hip arthroplasty is well analyzed and shows accurate results, reducing cup outliers of Lewinnek's "safe zone." With regard to the combined anteversion of cup and stem, however, a "new" safe zone with a range of 25° to 50° has been published. The aim of this study was to analyze total anteversion (cup and stem) by postoperative 3D computed tomography in isolated cup navigation cases. In 46 patients, the mean combined anteversion was 34.4° (range, 16.3°-57.3°, SD ± 9.3°) with 10 outliers. The mean cup anteversion was 19.5° (range, 11°-27°, SD ± 3.7°). Regarding Lewinnek's "safe zone" (cup only), we observed 5 outliers. An improvement of technique of stem implantation or navigation may reduce outliers of combined anteversion.

Improving Cup Positioning Using a Mechanical Navigation Instrument

Although surgical navigation reduces the rate of malpositioned acetabular cups in total hip arthroplasty (THA), its use has not been widely adopted. As a result of our perceived need for simple and efficient methods of navigation, we developed a mechanical navigation device for acetabular cup orientation. We assessed accuracy of cup orientation (mean error of cup inclination and anteversion) of a novel mechanical navigation device, percentage of outliers, length of operation, and compared the results with a series of CT-based computer-assisted THAs. Cup orientation of 70 THAs performed using the mechanical navigation device was compared with a historical control group of 146 THAs performed using CT-based computer navigation. Postoperative cup orientation was measured using a validated two-dimensional/three-dimensional matching method. An outlier was defined outside a range of ± 10° from the planned inclination and/or anteversion. Using the mechanical navigation device, we observed a decrease in the errors of inclination (1.3° ± 3.4° [range, -6.6° to 8.2°] versus 3.5° ± 4.2° [-12.7° to 6.9°]), errors of anteversion (1.0° ± 4.1° [-8.8° to 9.5°] versus 3.0° ± 5.8° [-11.8° to 19.6°]), percentages of outliers (0% versus 9.6%), and length of operation (112 ± 22 [78-184] minutes versus 132 ± 18 [90-197] minutes) compared with CT-based navigation. Compared with CT-based surgical navigation, navigation of acetabular cup orientation using a mechanical device can be performed in less time, lower mean errors, and minimal equipment.