Mean Cup Inclination Research Articles

A correction factor is needed for the intraoperative measurement of cup inclination in total hip arthroplasty.

The cup inclination in total hip arthroplasty is key to minimising complications. Stereometric effects (parallax) in two-dimensional projections can alter angle measurements. Even for different approaches, fluoroscopy causes different results in the measurement of inclination. A previous study has introduced a corrective factor for intraoperative radiographic cup inclination measurements compared to the postoperative standing radiographs. The aim of this study was to find out whether, first, the correction factor is reproducible and second, whether the correction factor is independent of the surgical approach and C-arm model used. A series of 377 cases of primary total hip arthroplasty was reviewed. We compared the cup inclination angle in the intraoperative and postoperative radiographic images. Based on this, it was possible to specify a standard of correction factor in defined ranges. The mean cup inclination in intraoperative images was 37.47∘ and the mean angle in postoperative images was 41.42, resulting in a mean difference of 3.95∘ with a strong correlation (r= 0.706). An added correction factor of 4∘ should be respected in intraoperative inclination measurements to adapt for parallax. An increased correction factor of 6∘ in particularly low-positioned cups (< 31∘) and a decreased correction factor of 2∘ in particularly steeply positioned cups (> 43∘) is recommended.

Is Outcome of Total Hip Arthroplasty for Hip Fracture Inferior to That of Arthritis in a Contemporary Arthroplasty Practice?

BackgroundOutcome of total hip arthroplasty (THA) for femoral neck fractures (FNF) has been associated with higher complication rates. However, THA for FNF is not always performed by arthroplasty surgeons. This study aimed to compare THA outcomes for FNF to osteoarthritis (OA). In doing so, we described contemporary THA failure modes for FNF performed by arthroplasty surgeons. MethodsThis was a retrospective, multisurgeon study from an academic center. Of FNFs treated between 2010 and 2020, 177 received THA by an arthroplasty surgeon [mean age 67 years (range, 42 to 97), sex: 64.4% women]. These were matched (1:2) for age and sex with 354 THAs performed for hip OA, by the same surgeons. No dual-mobilities were used. Outcomes included radiologic measurements (inclination/anteversion and leg length), mortality, complications, reoperation rates and patient-reported outcomes including Oxford Hip Score. ResultsPostoperative mean leg-length difference was 0 mm (range, −10 to −10 mm), with a mean cup inclination and anteversion of 41 and 26°, respectively. There was no difference in radiological measurements between FNF and OA patients (P = .3). At a 5-year follow-up, mortality rate was significantly higher in the FNF-THA group compared to the OA-THA group (15.3 versus 1.1%; P < .001). There was no difference in complications (7.3 versus 4.2%; P = .098) or reoperation rates (5.1 versus 2.9%; P = .142) between the groups. Dislocation rate was 1.7%. Oxford Hip Score at the final follow-up was similar [43.7 points (range, 10 to 48) versus 43.6 points (range, 10 to 48); P = .030]. ConclusionTHA for the treatment of FNF is a reliable option and is associated with satisfactory outcomes. Instability was not a common reason of failure, despite not using dual-mobility articulations in this at-risk population. This is likely due to THAs being performed by the arthroplasty staff. When patients live beyond 2 years, similar clinical and radiographic outcomes with low rates of revision can be expected compared to elective THA for OA. Level of evidenceIII, case-control study.

The Safety and Efficacy of the Anterior Approach Total Hip Arthroplasty as per Body Mass Index

BackgroundObesity is associated with component malpositioning and increased revision risk after total hip arthroplasty (THA). With anterior approaches (AAs) becoming increasingly popular, the goal of this study was to assess whether clinical outcome post-AA-THA is affected by body mass index (BMI). MethodsThis multicenter, multisurgeon, consecutive case series used a prospective database of 1,784 AA-THAs (1,597 patients) through bikini (n = 1,172) or standard (n = 612) incisions. Mean age was 63 years (range, 20-94 years) and there were 57.5% women, who had a mean follow-up of 2.7 years (range, 2.0-4.1 years). Patients were classified into the following BMI groups: normal (BMI < 25.0; n = 572); overweight (BMI: 25.0-29.9; n = 739); obese (BMI: 30.0-34.9; n = 330); and severely obese (BMI ≥ 35.0; n = 143). Outcomes evaluated included hip reconstruction (inclination/anteversion and leg-length, complications, and revision rates) and patient-reported outcomes including Oxford Hip Scores (OHS). ResultsMean postoperative leg-length difference was 2.0 mm (range: −17.5 to 39.0) with a mean cup inclination of 34.8° (range, 14.0-58.0°) and anteversion of 20.3° (range, 8.0-38.6°). Radiographic measurements were similar between BMI groups (P = .1-.7). Complication and revision rates were 2.5% and 1.7%, respectively. The most common complications were fracture (0.7%), periprosthetic joint infection (PJI) (0.5%), and dislocation (0.5%). There was no difference in dislocation (P = .885) or fracture rates (P = .588) between BMI groups. There was a higher rate of wound complications (1.8%; P = .053) and PJIs (2.1%; P = .029) among obese and severely obese patients. Wound complications were less common among obese patients with the ‘bikini’ incision (odds ratio 2.7). Preoperative OHS was worse among the severely obese (P < .001), which showed similar improvements (Change in OHS; P = .144). ConclusionAA-THA is a credible option for obese patients, with low dislocation or fracture risk and excellent ability to reconstruct the hip, leading to comparable functional improvements among BMI groups. Obese patients have a higher risk of PJIs. Bikini incision for AA-THA can help minimize the risk of wound complications.

Short term analysis of total hip replacement done with constrained acetabular component - functional and radiological outcome

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Dislocation remains at the forefront of complications after primary total hip arthroplasty (THA). In our study, we talk about the use of constrained liners and its outcomes in an unstable hip.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; The total number of patients included in the study was 15. The total number of hips in the study were 15. The age group of the patients varied between 51 years and 89 years with mean age group of 73 years. The most common indication in our study was dislocation contributing 60% (n=9) of the hips.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; The post-operative mean Harris hip score (HHS) at immediate post-operative was 67.6. There was a gradual improvement in the HHS through 6 months (77.6), one year (83.3), two years (86.7) and 3 years (90.33). There were no cases with post-operative septic or aseptic loosening in the radiological analysis. The mean cup inclination was 34.3. Out of the 13 hips, in eight hips the femoral stem was in varus. Five hips had a centrally placed femoral stem. Stability management in THA have seen the component design take centre stage, primarily with the use of larger diameter femoral heads and the rise in popularity of constrained acetabular liners (CAL). Several authors have done studies which talk about the stability of this implant design and the reliability of this implant in unstable hips and in hips where instability was expected.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; In our study, proximal femur tumours, dislocated total hips, abductor insufficiencies and aseptic loosening all showed good results.&lt;/p&gt;

An audit on the accuracy of freehand acetabular cup positioning in total hip arthroplasty with the direct lateral approach at a tertiary institution over seven years

BACKGROUND: The direct lateral approach for total hip replacement has been traditionally reserved and described for neck of femur fractures. Advantages of this approach include technically easy access to the acetabulum and femur and low incidence of hip dislocation. Imperfect positioning of the acetabular component leads to increased risk for dislocations, accelerated wear, reduced range of motion and increased revision rate. Freehand technique has been the gold standard for many decades, but newer technologies like computer navigation and robotic-assisted surgery have shown to improve the accuracy of cup placement. This study reports on the accuracy of freehand cup positioning via the direct lateral approach with mention of the dislocation rate METHODS: We retrospectively reviewed 253 patients who had total hip replacements done via the direct lateral approach. The patients' files were evaluated for patient parameters, demographic details, aetiology of hip pathology, confirmation of approach used, comorbidities and history of previous relevant surgery. The postoperative radiographs were analysed for acetabular component position inclination and anteversion. Dislocation rates were calculated as a secondary objective RESULTS: The radiographic analysis was performed using the Liaw method based on trigonometry of the eclipse generated. This showed a mean cup inclination of 42.3° (95% CI: 41.3-43.3°) and anteversion of 12.7° (95% CI: 12.0-13.7°). A total of 57% of the acetabular cups were within the safe zones described by Lewinnek. Of them, 78% were in the 30-50° range for inclination and 73% in the 5-25° range for anteversion. There were ten dislocations within one year from the index procedure: a dislocation rate of 4.0% (95% CI: 2.8-8.5% CONCLUSION: The freehand technique using the direct lateral approach for acetabular cup placement produces a poor overall accuracy of only 57%. Although our study only commented on ten dislocations, the rate (4%) is significantly worse compared to the 0.43% reported in literature for the direct lateral approach. The radiographic results for inclination and anteversion are comparable to other freehand techniques, regardless of the approach used, but significantly worse than results achieved with navigation and robotics Level of evidence: Level 4

Modular Dual Mobility Constructs Used for Recurrent Hip Instability.

BackgroundRecurrent hip dislocation despite prior attempts at surgical stabilization is a dreadful and technically challenging complication. A modular dual mobility (MDM) articulation has shown promise in addressing this problem, which might seem intractable. Our purpose was to examine the outcomes of revision total hip arthroplasty (THA) with an MDM placed through a direct anterior (DA) approach when all other conservative and surgical treatments have failed.MethodsFifteen patients revised with an MDM for recurrent instability (RI) between 2012 and 2018 by a single surgeon at a single institution were reviewed retrospectively, with a minimum of two years' follow-up. All patients underwent full acetabular revision with an MDM articulation through a DA approach with intraoperative fluoroscopy. No stems were revised. Dislocations, complications, and clinical outcomes are reported.Results All patients had recurrent posterior instability with a mean number of 4 ± 2 (range: 2 to 8) dislocations prior to MDM revision THA (MDM rTHA). Eight patients had already failed surgical intervention for instability, and seven had failed repeated closed reductions and conservative care. After MDM rTHA, there were no dislocations at a mean follow-up of 4 ± 1 years (range: 2 to 8). Similarly, there were no further revisions or reoperations. Postoperatively, the mean cup inclination improved to 45 ± 2 degrees (range: 41 to 48), and the mean anteversion improved to 20 ± 2 degrees (range: 17 to 23). All cups were well-positioned utilizing fluoroscopic guidance. The mean effective head size increased from 32 mm to 44 mm. The mean hip disability and osteoarthritis disability score (HOOS, Jr) was 73 ± 25% (range: 40 to 100).ConclusionRefractory hip instability in THA may be effectively managed with an MDM articulation, even when prior attempts at surgical stabilization have failed. Intraoperative imaging and a direct anterior approach may aid the challenges of implant positioning and achieving hip stability in a revision setting.

Supercapsular Percutaneously Assisted total hip arthroplasty versus lateral approach in Total Hip Replacement. A prospective comparative study

BackgroundSupercapsular Percutaneously Assisted total hip arthroplasty (SuperPATH approach) is a relatively new minimal invasive approach which has been associated with encouraging postoperative outcomes. The aim of this study is to compare the minimal invasive (MIS) SuperPATHapproach with the standard modified Hardinge approach at the base of muscle damage due to serum markers, functional results and other perioperative and postoperative data. Material and methodsForty eight (48) consecutive patients undergone primary total hip arthroplasty (THA) by the same surgeon (GD), were enrolled in our study. From this study population, the modified Hardinge approach was performed in 23 patients and the SuperPATH approach was performed in 25 patients. Soft tissue impairment was studied based on three representative markers, C-reactive-protein (CRP) and two enzymes, creatine kinase (CK) and lactate dehydrogenase (LDH). We measured these markers 10 min after surgery, on 1st and 2nd postoperative day. The levels of the perceived pain were evaluated according to the Visual Analog Scale/Numerical Rating Scale (VAS/NRS) score which was registered 6 h, 12 h, 1 day and 2 days postoperatively. The functional and clinical evaluation of the patients was achieved with Harris Hip Score (HHS), Charnley's Hip score, EuroQol (EQ-5D)-(EQ-100), Patient Health Questionnaire (PHQ-9) and neuropathic pain questionnaire (DN-4) 6 months and 1 year postoperatively. The rest of the collected data included patient's age, gender, body mass index (BMI), other comorbitities, the American Society of Anesthiologists score (ASA), Charlson Index score, the pre-operative diagnosis, implant positioning through radiographic evaluation, the type of anesthesia, the days of hospitalization, the operating time, incision length, blood loss and blood transfusion requirements and complication rates. ResultsSuperPATH approach was related with statistically considerable lower levels of CRP at 10 min (p = 0,001) and at 24 h (p = 0,047) postoperatively, as well as lower LDH levels in all time points postoperatively. It was also associated with shorter incision length (p < 0.001), longer operating time (p < 0.001), higher mean cup inclination p < 0.001, decreased postoperative pain levels the first 6 and 12 h (p < 0.001) and relatively better clinical and functional results 6 months after surgery, but not at 12 months. ConclusionOur study revealed some advantages in favor of the SuperPATH approach comparing with the standard modified Hardinge approach, mainly in terms of less muscle damage and less perceived pain postoperatively. More research is required in order to further elucidate its efficacy.

Biomechanical reconstruction parameters obtained after direct anterior approach total hip arthroplasty do not compromise clinical outcome.

Accurate reconstruction of biomechanical parameters following total hip arthroplasty (THA) is crucial for good joint function. We investigated how reconstruction parameters achieved by minimally invasive anterior (MIS) THA may influence function and patient-related outcomes. A consecutive series of 95 patients treated by MIS THA for primary osteoarthritis were retrospectively reviewed. Primary outcome measures were Harris Hip Score (HHS), hip disability and osteoarthritis outcome score (HOOS) and EQ-5D. Femoral offset (FO), abductor lever arm (ALA), centre of rotation (CoR), leg length discrepancy (LLD), cup version and stem alignment were measured pre- and post-operatively. Obtained reconstruction parameters compared to the contralateral hip were used as independent variables in a multivariate regression with each primary outcome measure as dependent variable. Mean age at surgery was 69years. HHS rated 94.7% of patients as good/excellent and mean EQ-5D was 0.82. Post-operative HOOS subscales showed no statistical difference compared to the Italian benchmark population. Stem alignment averaged 0.2° valgus, mean cup inclination was 37.8° and mean anteversion was 12.8°. When compared to the contralateral side, CoR was post-operatively elevated by 2.6mm and medialized by 2.4mm averagely. An average FO reduction of -0.5mm was observed while FO ratio increased by 1.9% averagely. ALA decreased by -3.3mm while LLD was 2.3mm averagely. Multivariate regression analysis revealed a significant contribution of ALA to HHS only. Biomechanical parameters achieved by MIS THA are satisfactory with negligible impact on functional results and no impact on patient-related outcomes certifying the high quality achieved in THA.

The direct anterior approach provokes varus stem alignment when using a collarless straight tapered stem.

Inaccurate stem implantation can cause unsatisfactory offset reconstruction and may result in insufficient gluteal muscle function or aseptic loosening. In this study, stem alignment of a collarless straight tapered HA-coated stem was retrospectively analyzed during the learning phase of the direct anterior approach (DAA) for primary total hip arthroplasty (THA). From Jan 2013 to Jun 2015, a total of 93 cementless THA were implanted in patients with unilateral coxarthrosis via the DAA in a two surgeon setting using the Corail® or Trendhip® stem (DePuy Synthes or Aesculap). Varus(+)/Valgus(-) stem alignment was analyzed in postoperative anteroposterior pelvic radiographs. Effects on femoral offset reconstruction and correlation to patient's individual clinical and radiological parameters were evaluated. 55 stems were implanted in varus (59%), 32 in neutral (34%) and 6 in valgus alignment (7%). Mean stem alignment in varus position was + 2.2° (SD ± 1.4°). Varus alignment was associated with male gender and preoperative coxa vara deformity: low CCD, high femoral offset and long thigh neck (p ≤ 0.001). Alignment was not correlated to femoral offset restoration, BMI or leg length difference. Mean cup inclination was 44° (SD ± 4.7°) and 90% matched the coronal Lewinnek safe zone. In the learning curve, the DAA can be associated with a high incidence of varus stem alignment when using a straight tapered stem, especially in men with coxa vara deformity: low CCD, high femoral offset and long thigh neck. An insufficient capsule release makes femur exposure more difficult and might be an additional factor for this finding. We recommend intraoperative X-ray in the learning phase of the DAA to verify correct implant positioning and to adjust offset options.

Attention Focus Does Not Influence Performance of Sit-to-Stand in Young and Older Adults

An external focus of attention can improve performance, but there is little research on effects for the elderly in every day, well-learned mobility tasks. 57 older and 59 young adults performed the sit-to-stand and stand-to-sit while holding a cup, at three difficulty levels (cup empty or full, at normal or fast speed). Half were instructed to focus internally (on their movements) and half externally (on the cup). The effects of focus, age, and difficulty level were tested for movement time, mean inclination of the cup, inclination variability, and smoothness with 2 × 2 × 3 ANOVAs. Significant effects of difficulty were consistent across variables (p < 0.05). An effect of focus was present only for the inclination variability of the stand-to-sit (p < 0.03), favoring an internal focus (less variability). The age × focus interaction was significant for mean cup inclination, but post hoc tests failed to reveal any significant differences. The results of this study, together with the literature, suggest that an external focus may not benefit the performance of young or older adults in general mobility activities of daily living. The prevalent assumption that an external focus is always beneficial for performance needs further empirical testing.

Optimal position of lipped acetabular liners to improve stability in total hip arthroplasty\u2014an intraoperative in vivo study

BackgroundLipped or elevated acetabular liners are frequently used in total hip arthroplasty to improve stability. However, the optimal position of the lip is not known. The purpose of this study was to determine the optimal position of lipped acetabular liners in total hip arthroplasty performed with a posterior approach.MethodsIn 14 hips, lipped trial liners were placed intraoperatively in various positions around the posterior clock-face of the implanted acetabular shell component. For each liner position, stability of the hip was tested at maximal hip flexion with gradually increasing internal rotation until subluxation occurred, at which point the position of the hip was measured using smartphone accelerometer-based goniometers. Smartphone goniometers were first validated against a computer-assisted navigation system. Post-operative radiographs were analyzed for cup inclination angle, cup anteversion angle, and femoral offset.ResultsMean cup inclination angle in our series was 31° ± 6°. The most common liner position that imparted the greatest stability to posterior subluxation was posteriorly and inferiorly (4 o’clock position for left hip, or 8 o’clock position for right hip). The range for most stable liner position for different patients varied from postero-superior (11 o’clock/1 o’clock position) to directly inferior (6 o’clock position). Comparing a non-lipped liner to a lipped liner placed in the optimal position, the average difference in internal rotation gained before dislocation was 23°. There was no association between cup inclination or anteversion angle with liner position of greatest stability.ConclusionIn hip replacements performed through a posterior approach and with mean cup inclination angle of 31° ± 6°, placing the lip of the elevated liner in the postero-inferior quadrant may impart more stability than in the postero-superior quadrant.

The minimalinvasive direct anterior approach in aseptic cup revision hip arthroplasty: a mid-term follow-up

The minimally invasive direct anterior approach (DAA) is an established approach for primary total hip arthroplasty (THA). The complication rates in hip revision arthroplasty are much higher in comparison with primary THA. A right positioning of the implants and a soft tissue, especially the abductors spearing approach, is important to get good functional results and low complication rates. The aim of this study was to show the clinical and radiological outcome of isolated revision hip arthroplasty of the cup by using the DAA. Aseptic cup revisions were carried out in 48 patients using the DAA. A decision to exchange the stem was made intraoperatively in seven cases. Complications, radiological and functional outcome were assessed. All of the data were collected retrospectively. The mean follow-up period was 65 months. In most of the cases the standard DAA was used. A proximal extension was nescessary in 15 patients (31%). The mean cup inclination angle after revision was 44° (min. 25°, max. 62°). Six implants (12.5%) were located outside of the Lewinnek safe zone. The centers of rotation of the revision implants were a mean of 0.6cm superior (min. 0, max. 2.2cm) and 0.5cm lateral (min. 0.2cm, max 1.2cm) in comparison with the center of rotation in the healthy hip on the contralateral side. Harris Hip Score improved significantly from 50 to 91 (P = 0.03). Complications noted consisted of two periprosthetic infections (4.2%), one aseptic cup loosening (2.1%), two hematomas requiring revision (4.2%), and one case each of femoral nerve injury, lower-leg venous thrombosis, and pneumonia. No dislocations were observed and there were no cases of heterotopic ossification based on the Brooker classification. No persistent damage of the nervus cutaneus femoris lateralis was found at the follow-up examinations. The DAA represents a feasible option in hip revision arthroplasty. Anatomic reconstruction of the cup is reproducibly possible. Good medium-term results can also be achieved. Particularly in relation to dislocation, the complication rates are low. Due to the learning curve, the DAA should only be used in hip revision arthroplasty by those with sufficient experience in primary THA. Adequate data regarding stem revisions through the DAA are not available at the moment.

Direct Anterior Approach Total Hip Arthroplasty Using a Morphometrically Optimized Femoral Stem, a Conventional Operating Table, Without Fluoroscopy

BackgroundOur experience with direct anterior approach total hip arthroplasty (THA) suggests that it can be performed successfully with a morphometrically optimized metaphyseal-diaphyseal engaging femoral stem (NOT a short stem), a regular operating room table (NOT a special custom table), and WITHOUT intraoperative fluoroscopy. We report our minimum 2-year results. MethodsA retrospective review of a single-surgeon series of primary direct anterior approach THAs was performed. All procedures were performed on a regular table, without fluoroscopy, using a cementless tapered femoral stem. Clinical, functional, and radiographic outcomes were evaluated at a minimum of 2 years. ResultsIn total, 1017 primary THAs were performed. The preoperative Harris Hip Score was 40.7 ± 5.1 and improved to 95.3 ± 4.2 at minimum 2-year follow-up. There were 3 dislocations (0.3%) and 15 revisions (1.5%): 7 for infection (0.7%), 4 for periprosthetic fractures (0.4%), 2 for instability (0.2%), 1 for loosening (0.1%), and 1 for pain (0.1%). Five patients (0.5%) required blood transfusion. One patient developed deep vein thrombosis and pulmonary embolism. No intraoperative fractures, perforation, or THA-related mortality occurred. Neutral stem alignment was confirmed in 98.3%. Mean cup inclination was 38.8° ± 5.1° and anteversion was 16.2° ± 3.5°. The mean leg-length discrepancy was corrected from 1.2 ± 0.2 cm preoperatively to 0.2 ± 0.1 cm postoperatively. ConclusionUsing a morphometrically optimized metaphyseal-diaphyseal engaging tapered femoral stem instead of a short stem reduces component malposition and minimizes risk of loosening. Combining the use of this implant design and the technique and elements described in our cohort demonstrated to have excellent results at 2 years. The patients will need continued follow-up to demonstrate further durability of this device and technique compared to others performing direct anterior THA.

Midterm results of Magnum large head metal-on-metal total hip arthroplasty

ObjectivesWe present the results of the prospective follow up of a sample of large head metal-metal total hip arthroplasty obtained after the safety alert regarding a higher incidence of revision of these implants. Material and methodsAll patients implanted with the Recap-M2a-Magnum cup between 2008 and 2011 were included. They were prospectively reviewed recording Harris Hip Score, clinical symptoms of chromium or cobalt intoxication. Serum levels of these ions were requested as well as X-rays and ultrasonography. An MRI was performed in the cases of positive ultrasonography. ResultsTwenty-six males with a mean age of 48.54 years [32–62, SD: 7.18] were included. An anterolateral approach and Bi-Metric (7) and F-40 (19) stems were used. Cephalic diameters ranged 42–52 (mode: 46) and the mean cup inclination was 39.35° [21–59°, SD: 9.78]. During follow-up (7.3 years [5.9–9.4; SD: .78]), 3 patients (11.5%) underwent revision (2 cases aseptic loosening, 1 pseudotumour). Mean time until revision was 5.4 years [3.1–8.0; SD: 2.48]. The accumulated survival probability was 88.5% (95% CI 76.3–100%). Harris Hip Score was 94.47 [66.5–100; SD: 8.94] and the patients showed no metallic intoxication symptoms. The levels of chromium were 1.88μg/dl [0.6–3.9] and cobalt 1,74μg/dl [0.5–5,6]. One pseudotumour was found in an asymptomatic patient, and small amounts of periarticular liquid were found in 5 patients (19.2%) Discussion and conclusionsHigh revision rates are still found when follow up is extended due to aseptic loosening and pseudotumour formation. MRI might not be the most adequate test to study the complications of these prostheses.

Resultados a medio plazo de la artroplastia total de cadera metal-metal con cabeza de gran tamaño Magnum

ObjectivesWe present the results of the prospective follow up of a sample of large head metal-metal total hip arthroplasty obtained after the safety alert regarding a higher incidence of revision of these implants. Material and methodsAll patients implanted with the Recap-M2a-Magnum cup between 2008 and 2011 were included. They were prospectively reviewed recording Harris Hip Score, clinical symptoms of chromium or cobalt intoxication. Serum levels of these ions were requested as well as X-Rays and ultrasonography. An MRI was performed in the cases of positive ultrasonography. ResultsTwenty-six males with a mean age of 48.54 years [32-62, SD: 7.18] were included. An anterolateral approach and Bi-Metric (7) and F-40 (19) stems were used. Cephalic diameters ranged 42-52 (mode: 46) and the mean cup inclination was 39.35° [21-59°, SD: 9.78]. During follow-up (7.3 years [5.9-9.4; SD: .78]), 3 patients (11.5%) underwent revision (2 cases aseptic loosening, 1 pseudotumour). Mean time until revision was 5.4 years [3.1-8.0; SD: 2.48]. The accumulated survival probability was 88.5% (95% CI 76.3-100%). Harris Hip Score was 94.47 [66.5-100; SD: 8.94] and the patients showed no metallic intoxication symptoms. The levels of chromium were 1.88 mcg/dl [0.6-3.9] and cobalt 1,74 mcg/dl [0.5-5,6]. One pseudotumour was found in an asymptomatic patient, and small amounts of periarticular liquid were found in 5 patients (19.2%) Discussion and conclusionsHigh revision rates are still found when follow up is extended due to aseptic loosening and pseudotumour formation. MRI might not be the most adequate test to study the complications of these prostheses.

Long-term results of metal on metal total hip arthroplasty in younger patients (

IntroductionMetal on Metal (MoM) hip arthroplasty saw a new era of popularity with development of its second generation bearing surfaces, in the first decade of this century. However, by the end of that decade, concerns had been raised due to metal debris related complications.We aimed to determine the survival of MoM stemmed hip replacement in younger population. We also studied the rate of revision related to adverse reaction to metal debris (ARMD) along with reviewing the clinical and radiological progress of MoM hip arthroplasty in younger age (<55 yrs) group. Patients & MethodsThis is a retrospective cohort study of patients 55 yrs old or younger, who had metal on metal (MoM) hip arthroplasty for osteoarthritis. We had 109 procedures performed on 90 patients with a mean follow up of 10 years. All patients were reviewed as per MHRA guidelines in planned follow-up clinics. Data analyses were performed using SPSS. ResultsSurvival of implant in our younger cohort was 88.1% at a mean age if 10 years, with revision for any cause as an endpoint. Most of the patients were happy with the outcome of their hip replacement as they were able to perform activities of daily living and work without compromise. Mean Oxford hip score was 43.Altogether, there were 12 revisions, 7 of these were for metallosis and associated symptoms. Average time to revision was 7 years. Other analysis revealed mean acetabular cup inclination angle to be 49 degrees but no significant correlation was found between this angle and serum metal ion levels. Serum Chromium and Cobalt levels were significantly higher in revision group. DiscussionMetal on metal hip arthroplasty prime popularity time has gone. In younger population, although revision rates are higher, the surviving implants give a very good outcome in terms of patient satisfaction. Most of the patients report a desired outcome of ‘forgotten hip’.

Midterm follow-up study of metal on metal total hip replacement

Background: Metallosis and pseudotumors are long discussed complications with metal on metal bearing total hip replacement which has increased the rate of revision total hip replacements in these patients. Aims and Objective: To evaluate the levels of metal ion (Cobalt and Chromium), factors affecting theses metal ion levels and incidence of pseudotumors in metal on metal total hip replacement patients. Materials And Methods: Prospective descriptive study done on 25 patients who had metal on metal bearing surface replacement and total hip replacement with a mean post-op period of 6 years. Serum metal ion levels (Cobalt and Chromium), MARS-MRI (Metal Artifact Reduction Sequence) and acetabular cup inclination angle on X-rays and functional score were recorded in theses patients on two follow-up visits with mean follow-up period of 1 year. Result: Mean cobalt was 1.64 and mean chromium was 3.06. 28% of the study population showed asymptomatic pseudotumors but were less than 5cm. Mean cup inclination angle was 41.8* on X-rays which did not have any influence on serum metal ions and functional score. Gender (Male / Female) and type of arthroplasty (Articular surface replacement / Total hip replacement) has no affect on serum metal ions. Functional scores of these metal on metal patients comparable to metal on polyethylene bearing patients. Revison total hip replacement done in one metal on metal THR patient who had a dislocated cup in his second follow-up. Conclusion: Metal on metal hip arthroplasty patients were functionally doing well like the regular metal on polyethylene patients. Chromium values were significant and higher than cobalt. Incidence of asymptomatic pseudotumors was 28%.

Hip resurfacing before 50years of age: A prospective study of 979 hips with a mean follow-up of 5.1years.

Hip resurfacing arthroplasty (HRA) is an alternative to total hip arthroplasty (THA) for the treatment of hip osteoarthritis in patients younger than 50 years. Data on revision rates after HRA are conflicting. The National Institute for Health and Care Excellence (NICE) recommends performing only those hip arthroplasty procedures associated with 10-year revision rates no greater than 5% (0.5% per year). Follow-up studies can rapidly determine whether this criterion is met. The uncertainties surrounding revision rates after HRA prompted us to design a study of prospectively enrolled patients aiming (1) to determine the revision rate after HRA performed before 50years of age and (2) to assess the functional, radiological, and biological outcomes of HRA. The revision rate after HRA performed before 50years of age meets the NICE criterion. Consecutive patients undergoing HRA before 50years of age were enrolled prospectively. The same implant was used in all patients. Functional outcomes were assessed based on the Harris Hip Score (HHS), Postel-Merle d'Aubigné (PMA) score, 12-item Oxford Hip Score (OHS), and UCLA activity score. Radiographic outcomes were assessed, and blood levels of chromium and cobalt were assayed. The study included 936 patients (979 HRAs) with a mean age of 42.7years (16.4-50.0years) at surgery and a mean follow-up of 5.1years (range: 3.1-9.0 years). All four mean functional scores were significantly improved at last follow-up vs. baseline: HHS, 95.9 (39.0-100) vs. 44.3 (18.0-83.0); PMA score, 17.6 (6.0-18.0) vs. 11.7 (3.0-16.0); OHS, 14.3 (12.0-37.0) vs. 40.6 (25.0-60.0); and UCLA activity score, 7.8 (2.0-10.0) vs. 5.6 (1.0-10.0) (p<0.0001). Mean cup inclination in the coronal plane was 42.1° (25.0°-68.0°). Mean blood cobalt level was significantly higher at last follow-up than at baseline (1.36μg/L [0.05-8.2μg/L] vs. 0.61μg/L [0.01-3.6]) (p<0.001). No patient experienced dislocation. Revision was required for 17 hips and involved changing the implant in 12 (1.2%). The 10-year survival rate with implant change, as the endpoint was 98.7% (95%CI, 97.6%-99.3%), indicating that the NICE criterion was easily met. The NICE criterion allows the rapid identification of prostheses with insufficient survival. HRA is theoretically associated with a high risk of aseptic mechanical loosening, as it is performed in young patients who have a high level of physical activity. Nevertheless, our study showed that implant survival after HRA was better than required by the NICE criterion. Thus, HRA is a valid alterative to THA in patients younger than 50years. IV, prospective study with no control group.

Incidence of Adverse Reactions to Metal Debris From 28-mm Metal-on-Metal Total Hip Arthroplasties With Minimum 10 Years of Follow-Up: Clinical, Laboratory, and Ultrasound Assessment of 44 Cases

BackgroundTotal hip arthroplasty with metal-on-metal (MoM) bearings has been suspected to cause adverse reactions to metal debris (ARMD), with the incidence varying greatly by implant type and patient gender. The prevalence of ARMD from small-diameter MoM bearings in women is unknown, especially after 10 years of follow-up (FU). MethodsCementless 28-mm MoM total hip arthroplasty bearings (Metasul) were implanted consecutively in 42 active women between 1996 and 2002. They were reviewed after a minimum of 10 years' FU with clinical, laboratory, radiological, and ultrasound assessments. ResultsMean FU was 15.9 years (range, 13-18). The mean Postel-Merle d'Aubigné and Oxford scores were 16.9 (range, 13-18) and 15.1 (range, 12-24), respectively, at FU. Mean cup inclination angle was 46.3° (range, 35°-57°). No femoral osteolysis was detected, but limited acetabular osteolysis (11%) over the screw holes occurred in 5 cases. No liquid or solid synovial reactions or ARMD were apparent on ultrasound, even in the 5 cases of pelvic osteolysis. Mean chromium levels were 1.32 μg/L (range, 0.1-7.9) and cobalt levels were 1.85 μg/L (range, 0.35-13.6). Cobalt was >3 μg/L in only 3 cases. The 15.9-year survivorship was 95% (range, 94.1%-98.9%). ConclusionReliable results were obtained with 28-mm MoM bearings, notably in young, active patients. This implant configuration requires very accurate positioning. No ARMD was seen in this group at 16 years' FU.

601 metal-on-metal total hip replacements with 36 mm heads a 5 minimum year follow up: Levels of ARMD remain low despite a comprehensive screening program

BackgroundWe conducted a retrospective study to assess the clinical outcome, failure rate, and reason for failure of a large consecutive series of 36mm MoM Corail/Pinnacle total hip replacements (THRs). MethodsBetween 2006 and 2011, 601 consecutive 36mm MoM THRs were performed (585 patients). Patients were followed according to the UK Medicines and Healthcare Products Regulatory Agency (MHRA) guidelines. All patients were accounted for and 469 patients (78%) were clinically and radiographically assessed. 328 females and 141 males with a median age of 73 (range 36–94 years) and a median follow up of 7.2 years (range 5.2–9.7 years) were followed. Clinical data included blood cobalt and chromium, Oxford Hip Score (OHS), plain radiograph, ultrasound of hip and intra-operative findings in those patients who had revision surgery. Results56 patients died of causes unrelated to their hip replacement. The mean survivorship of the implant was 92.8% (range 91.6–94%, 95% CI) at a median time to follow up of 84 months (62–113 months).The functional outcome was good with a median OHS of 38 out of 48 (23–44). The dislocation rate was 0.99%, with all these 6 cases requiring revision.476 patients had blood tests. 100 patients (21%) had elevated levels of either cobalt above MHRA guidelines of 7 parts per billion (120 and 135nmol/L respectively for cobalt and chromium). Cobalt was elevated independently of chromium in 75% of the cases (but never vice versa).The mean cup inclination angle was 42°. Each incremental stem size increase resulted in a decrease in cobalt by 11nmol/L.The most common reason for revision was adverse reaction to metal debris (ARMD) (12 cases). ConclusionThis paper is the largest and longest follow up of 36mm MoM THRs. Using the MHRA guidelines for follow up, the revision rates of this cohort has remained low compared to other studies, but unacceptably higher than that of other bearing surfaces. Level of evidenceIII.