Does the Dual Mobility Cup Reduce Dislocation After Primary Total Hip Arthroplasty in Elderly Patients at High Risk of Dislocation?

OBJECTIVE: The dual mobility cup (DMC) is designed to extend the longevity of the prosthesis by improving stability, enhancing the range of motion, and decreasing impingement without increasing wear. We hypothesized that DMC would reduce the risk of dislocation in elderly patients. This study aimed to investigate the clinical and radiographic outcomes of DMC-total hip arthroplasty (THA) in elderly patients at high risk of dislocation. METHODS: From June 2016 to March 2020, 94 patients with a mean age of 77.7 years (97 hips) who underwent a posterolateral approach for DMC-THA in our department were followed up for at least one year. Preoperative and postoperative pelvic tilt angles (PTA) and DMC orientation were prospectively collected for all patients. Intraoperative and postoperative complications were recorded. A parametric test was used for normal distribution, and a non-parametric test was used for non-normal distribution. RESULTS: Abduction and anteversion angles of the cup were 42.4 and 18.0° in the supine position immediately postoperative. The average PTA for patients in the supine and standing positions were 26.5 and 34.5°, respectively. When moving from the supine to the standing position, patients experienced a mean posterior pelvic tilt of 9°. No intraoperative acetabular-related complications were recorded. Postoperative complications included early infection in one patient (1.0%) and dislocation in one patient (1.0%). CONCLUSION: Our study demonstrates that DMC-THA provides satisfactory short-term outcomes in elderly patients at a high risk of dislocation, regardless of the change in PTA resulting from postural transition.

Integrating the Combined Sagittal Index Reduces the Risk of Dislocation Following Total Hip Replacement.

BACKGROUND: The aims of this matched cohort study were to (1) assess differences in spinopelvic characteristics between patients who sustained a dislocation after total hip arthroplasty (THA) and a control group without a dislocation, (2) identify spinopelvic characteristics associated with the risk of dislocation, and (3) propose an algorithm including individual spinopelvic characteristics to define an optimized cup orientation target to minimize dislocation risk. METHODS: Fifty patients with a history of THA dislocation (29 posterior and 21 anterior dislocations) were matched for age, sex, body mass index (BMI), index diagnosis, surgical approach, and femoral head size with 200 controls. All patients underwent detailed quasi-static radiographic evaluations of the coronal (offset, center of rotation, and cup inclination/anteversion) and sagittal (pelvic tilt [PT], sacral slope [SS], pelvic incidence [PI], lumbar lordosis [LL], pelvic-femoral angle [PFA], and cup anteinclination [AI]) reconstructions. The spinopelvic balance (PI - LL), combined sagittal index (CSI = PFA + cup AI), and Hip-User Index were determined. Parameters were compared between the control and dislocation groups (2-group analysis) and between the controls and 2 dislocation groups identified according to the direction of the dislocation (3-group analysis). Important thresholds were determined from receiver operating characteristic (ROC) curve analyses and the mean values of the control group; thresholds were expanded incrementally in conjunction with running-hypothesis tests. RESULTS: There were no coronal differences, other than cup anteversion, between groups. However, most sagittal parameters (LL, PT, CSI, PI - LL, and Hip-User Index) differed significantly. The 3 strongest predictors of instability were PI - LL >10° (sensitivity of 70% and specificity of 65% for instability regardless of direction), CSIstanding of <216° (posterior instability), and CSIstanding of >244° (anterior instability). A CSI that was not between 205° and 245° on the standing radiograph (CSIstanding) was associated with a significantly increased dislocation risk (odds ratio [OR]: 4.2; 95% confidence interval [CI]: 2.2 to 8.2; p < 0.001). In patients with an unbalanced and/or rigid lumbar spine, a CSIstanding that was not 215° to 235° was associated with a significantly increased dislocation risk (OR: 5.1; 95% CI: 1.8 to 14.9; p = 0.001). CONCLUSIONS: Spinopelvic imbalance (PI - LL >10°) determined from a preoperative standing lateral spinopelvic radiograph can be a useful screening tool, alerting surgeons that a patient is at increased dislocation risk. Measurement of the PFA preoperatively provides valuable information to determine the optimum cup orientation to aim for a CSIstanding of 205° to 245°, which is associated with a reduced dislocation risk. For patients at increased dislocation risk due to spinopelvic imbalance (PI - LL >10°), the range for the optimum CSI is narrower. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Do We Really Need to Worry About Calcaneocuboid Subluxation During Lateral Column Lengthening for Planovalgus Foot Deformity?

BACKGROUND: Although lengthening of the lateral column through an osteotomy of the anterior calcaneus is an integral component of flatfoot reconstruction in younger patients with flexible planovalgus deformities, the procedure has been implicated in iatrogenic calcaneocuboid (CC) subluxation and subsequent degenerative changes at the CC articulation. The purpose of this study is to characterize alterations at the CC joint after lateral column lengthening (LCL) and determine if Steinmann pin stabilization of the CC joint before distraction maintains a normal relationship. METHODS: Seven matched pairs of fresh-frozen cadaveric feet underwent preprocedure plain radiography and cross-sectional computed tomography (CT) imaging. LCL by osteotomy through the anterior calcaneus was then performed. One foot of each matched pair had a single smooth Steinmann pin placed centrally across the CC joint before osteotomy distraction. Distraction across each osteotomy was then performed and maintained with a 12-mm porous titanium wedge. Repeat imaging was obtained and compared with preprocedure studies to quantify sagittal and rotational differences at the CC articulation. RESULTS: Following LCL, plain radiography demonstrated statistically significant increases in the percentage of the calcaneal articular surface dorsal to the superior aspect of the cuboid in both the pinned (8.2% vs. 17.6%, P=0.02) and unpinned (12.5% vs. 16.3%, P=0.04) specimens. No difference in the percentage of subluxation was found between the 2 groups after LCL. CT imaging demonstrated statistically significant increases in rotation between the calcaneus and cuboid after LCL in both the pinned (7.6±5.6 degrees, P=0.01) and unpinned (17±12.3 degrees, P=0.01) specimens. The degree of rotation was greater in unpinned specimens after LCL (P=0.043). CONCLUSIONS: Both sagittal and rotatory subluxation seem to occur at the CC joint after LCL regardless of pin stabilization. As a single pin would be expected to limit pure translation while having little effect on rotation, it is possible that the rotational changes identified on 3-dimensional imaging are interpreted as dorsal translation when viewed 2 dimensionally using plain radiography. Consideration should therefore be given to CC stabilization with 2 pins during LCL to prevent this rotatory subluxation. LEVEL OF EVIDENCE: Level V-cadaver study.

Simulation of Implant Impingement After Spinal Corrective Fusion Surgery in Patients with Previous Total Hip Arthroplasty: A Retrospective Case Series.

STUDY DESIGN: A retrospective case series. OBJECTIVE: The aim of this study was to introduce the prevention of total hip arthroplasty (THA) dislocation using an implant impingement simulation after spinal corrective fusion and to verify the outcomes. SUMMARY OF BACKGROUND DATA: A high dislocation rate was found among patients who underwent spinal deformity corrective fusion with previous THA. To avoid dislocation, an appropriate position of the stem and cup is important, but the pelvic inclination may change after corrective fusion for spinal deformity. METHODS: Twelve consecutive patients (two men, 10 women; average age, 72.1 [range, 55-81] years during spine surgery) with previous THA were included. Data were retrospectively retrieved from a single-center's prospectively collected database of adult spinal deformity operation. Before surgery, anterior implant impingement simulation in THA was performed using computed tomography-based software. The tolerable pelvic tilt (PT) in which the anterior implant impingement occurred in the hip at the 120° flexion position was measured. The lumbar lordosis angle was deliberately reduced during spinal surgery according to the tolerable PT. The effect of the implant impingement simulation was verified by comparison with patients who underwent surgery before simulation (before 2014). RESULTS: THA dislocation occurred in six patients: four of five (80%) in the non-simulation, and two of seven (28.6%) in the simulation group. The difference between the preoperative and tolerable PT angles was-25° to 33°, and three patients had negative angles. In these three patients, the risk of anterior impingement and THA dislocation significantly increased with correction of lumbar lordosis if the PT was anterior. Two patients experienced repeated THA dislocation with postoperative and tolerable PT angle differences of 2° and -23°. CONCLUSION: Our simulation of anterior implant impingement and subsequent adjustment of the degree of spinal correction was useful to prevent dislocation. However, this method did not prevent dislocation in some patients.Level of Evidence: 4.

Suture anchor fixation may be an alternative to tension band wiring in olecranon fractures: Finite element analysis.

OBJECTIVES: This study aims to analyze and compare total deformations with tension band wiring (TBW), intramedullary screw (IS) and novel suture anchor (SA) fixation methods, and to investigate practicality of SA fixation in olecranon fractures using finite element analysis (FEA). MATERIALS AND METHODS: This finite element analysis study was conducted between May 2019 and October 2019. TBW, IS and SA fixation methods were compared in order to analyze fracture behavior in the ulna and humerus using FEA, which is among the mathematical methods of stress analysis. Boundary conditions were applied to the created model and total deformation amounts were compared among the methods in terms of displacement. RESULTS: The lowest amount of displacement was obtained with TBW method (1.2095 mm), while IS method (2.7703 mm) showed the highest amount of total displacement. Total displacement was lower with SA system (2.0397 mm) compared to IS fixation. In addition, no problem was observed with SA system in terms of failure occurrence. CONCLUSION: According to the results of FEA, although the lowest amount of displacement was obtained with TBW, it is concluded that anchor fixation method may be an alternative with practicality and mechanical properties. However, further studies are needed to obtain more precise data.

Factors contributing to disability in rheumatoid arthritis patients: an Egyptian multicenter study / Factores que contribuyen a la discapacidad en pacientes con artritis reumatoide: un estudio multicéntrico egipcio

OBJECTIVE: Minimizing disability and enhancing physical function to its optimal levels is still a challenge in management of rheumatoid arthritis (RA). The aim is to identify factors leading to disability in RA. METHODS: This is a cross-sectional Egyptian multicenter study carried out on 215 RA patients attending to our inpatient and outpatient rheumatology clinics during 4 months starting from April to July 2017 who agreed to participate in the study; 170 patients were from Cairo University hospitals and 45 from Zagazig University hospitals. We recorded a number of possible risk factors including demographic, clinical, serological and therapeutic factors. The assessment of patients' disability was done using Modified HAQ (MHAQ). RESULTS: A significant positive correlation was found between MHAQ and different markers of activity in addition to age and depression score (P<0.001). Illiteracy accounted for higher MHAQ scores (P=0.001). A higher MHAQ was found in patients with ischemic heart disease (P<0.05). Patients with erosions on X-rays had significantly higher MHAQ scores. Subluxations also accounted for higher MHAQ scores (P=0.000). CONCLUSION: Aging, illiteracy, disease activity, erosions, subluxations, depression and ischemic heart disease were all related to higher disability. Good control of disease activity which in turn reduces erosions and subluxations is mandatory. Screening for depression and proper use of anti-depressants is of great value. Proper screening and prophylaxis is recommended against ischemic heart disease by controlling modifiable risk factors like obesity, dyslipidaemia, hypertension, smoking and sedentary lifestyle

OBJETIVO: Minimizar la discapacidad y mejorar la función física hasta sus niveles óptimos sigue siendo un desafío en el tratamiento de la artritis reumatoide (AR). El objetivo es identificar los factores que conducen a la discapacidad en la AR. MÉTODOS: Se trata de un estudio multicéntrico egipcio de corte transversal llevado a cabo en 215 pacientes con AR que asisten a nuestras clínicas de reumatología para pacientes internados y ambulatorios durante 4 meses, desde abril a julio de 2017, que aceptaron participar en el estudio; 170 pacientes eran de hospitales de la Universidad de El Cairo y 45 de hospitales de la Universidad de Zagazig. Registramos una serie de posibles factores de riesgo que incluyen factores demográficos, clínicos, serológicos y terapéuticos. La evaluación de la discapacidad de los pacientes se realizó utilizando HAQ modificado (MHAQ). RESULTADOS: Se encontró una correlación positiva significativa entre MHAQ y diferentes marcadores de actividad además de la puntuación de edad y depresión (p < 0,001). El analfabetismo representó un puntaje MHAQ más alto (p = 0,001). Se encontró un MHAQ más alto en pacientes con cardiopatía isquémica (p < 0,05). Los pacientes con erosiones en los rayos X tuvieron puntajes de MHAQ significativamente más altos. Las subluxaciones también representaron puntuaciones más altas de MHAQ (p = 0,000). CONCLUSIÓN: El envejecimiento, el analfabetismo, la actividad de la enfermedad, las erosiones, las subluxaciones, la depresión y la cardiopatía isquémica se relacionaron con una mayor discapacidad. El buen control de la actividad de la enfermedad que a su vez reduce las erosiones y las subluxaciones es obligatorio. La detección de la depresión y el uso adecuado de antidepresivos es de gran valor. Se recomienda la detección y profilaxis adecuada de la cardiopatía isquémica controlando los factores de riesgo modificables como la obesidad, la dislipidemia, la hipertensión, el tabaquismo y el estilo de vida sedentario

The Hip-Spine Relationship Simplified.

Much attention has recently been focused on the relationship between the hip and spine and its contribution to postoperative instability following total hip arthroplasty. However, the terminology can be confusing. Through an understanding of spinopelvic parameters, spinopelvic motion, and the interplay between the spine and pelvis, the surgeon can plan for and decrease the risk of instability after total hip arthroplasty. This review details spinopelvic parameters that predispose to instability and guides readers in understanding spinopelvic motion as it relates to THA instability.

Does a computed tomography-based navigation system reduce the risk of dislocation after total hip arthroplasty in patients with osteonecrosis of the femoral head? A propensity score analysis.

This study aimed to investigate whether use of a computed tomography (CT)-based navigation system reduce the risk of dislocation after total hip arthroplasty (THA) in patients with osteonecrosis of the femoral head (ONFH). A total of 271 hips from 192 consecutive patients that underwent primary THA for ONFH were included. There were 110 hips in non-navigation group, and 161 hips in navigation group. After applying exclusion criteria, 209 hips from 149 patients were selected for analysis. Clinical outcomes and complication rates were evaluated, and implant alignments were also calculated. To identify whether the navigation system was useful to prevent dislocation, the inverse probability of treatment-weighted Cox regression analysis using a propensity score in relationship to sex, age at surgery, body mass index, and femoral head size was performed. No significant difference was observed in clinical scores between both groups. Dislocation was significantly lower in the navigation group (3 hips, 2.7%) than in the non-navigation group (11 hips, 11.2%; p = 0.012), whereas periprosthetic joint infection and aseptic loosening did not differ between the groups. Variance of cup inclination and anteversion angles was smaller in the navigation group than in the non-navigation group (p < 0.001). Use of the CT-based navigation system (hazard ratio; 0.26, 95% confidence interval, 0.07-0.98; p = 0.047) turned out to be the predictor for preventing dislocation. In conclusion, use of the CT-based navigation system provided a precise placement of components, and thus helps to prevent dislocation in patients with ONFH in the propensity score analysis.

Predicting Radial Head Instability in Multiple Hereditary Exostoses (MHE): A Multicenter Analysis of Risk Factors.

BACKGROUND: Forearm deformity occurs in one third of patients with multiple hereditary exostoses (MHE). Conservative and surgical treatment are aimed at preventing radial head subluxation and/or dislocation. Dislocation has been associated with isolated distal ulnar lesions, radial bowing, and ulnar shortening. Risk factors for radial head subluxation have not been clearly elucidated. This study aimed to identify risk factors for all radial head instability in MHE, to optimize early detection and prevent frank dislocation. METHODS: This multicenter retrospective case-control investigation included MHE patients with forearm lesions seen between 2000 and 2017 at 2 tertiary care children's hospitals. Demographic, clinical factors, radiographic measures, and surgical history were quantified. Comparisons were made between forearms that developed radial head instability versus those that remained stable and between those that progressed to radial head subluxation versus those that progressed to dislocation. RESULTS: This study included 171 forearms in 113 patients with MHE, who presented at a mean age of 8.0 years with a median follow-up time of 6.0 years. Nine forearms progressed to radial head subluxation (mean age: 10.2 y), and 24 forearms had radial head dislocation (mean age: 9.9 y). Five subluxations and 3 dislocations occurred despite preventative surgery. Initial radial bowing (7.2% vs. 8.5%, P=0.04), ulnar variance (-5.8% vs. 11.0%, P<0.001), and ulnar shortening (-2.5 vs. 9.1 mm, P=0.04) were predictive of radial head instability. Distal ulnar lesions and more severe ulnar variance (-5.8 vs. -10.6, P<0.001) and shortening (-2.5 vs. 13.2 mm, P=0.02) were associated with an increased risk of radial head subluxation. No significant differences were identified between forearms that progressed to subluxation versus those that progressed to dislocation. CONCLUSIONS: Distal ulnar lesions and radiographic measures can be used to determine the risk of radial head instability in MHE. Ulnar variance and shortening are early identifiable risk factors for radial head subluxation that can help guide monitoring and treatment. Radial bowing may be a late predictor of instability. LEVEL OF EVIDENCE: Level III-prognostic.

Intra-articular Radial Head Fractures: A Deceptive Type of Injury.

BACKGROUND: Isolated intra-articular radial head (IARH) fractures in skeletally immature patients represent a rare injury. Despite their initial benign radiologic appearance, these fractures are at risk for progressive radial head subluxation and may end with degenerative irreversible changes of the radiocapitellar joint. The aim of this study is to highlight the seriousness of these injuries and the importance of early diagnosis and a proper follow-up to achieve optimal outcomes. METHODS: We retrospectively reviewed 6 patients with IARH fractures treated at our institution between 2011 and 2016. All patients presented with Salter-Harris types III or IV fracture. Five of 6 fractures were initially undisplaced. Treatment, clinical, and radiographic results were analyzed. Patients were divided into 2 groups according to treatment: patients included in group A were treated conservatively, whereas patients of group B were treated with early surgery. The final functional outcome was assessed using the Oxford Elbow Score (OES). The Broberg-Morrey classification was used for the radiographic results. RESULTS: Group A included 3 patients (average age, 11±2 y). They developed an initially missed posterior subluxation of the radiocapitellar joint that caused to all of them a painful elbow and limited range of motion (ROM). Despite rescue surgery, they all presented with limited ROM at the final follow-up, although no functional limitations (OES, 46.3±2.9). The radiographs showed early degenerative changes. Group B included 3 patients (average age, 11±1 y) all treated surgically within 1 week from the injury. They showed no limitation of ROM and good functional (OES, 47.7) and radiologic outcomes. CONCLUSIONS: IARH fractures in skeletally immature children are deceptive injuries which are often underestimated. Surgeons should be aware of these fractures, especially when a discrepancy between the clinical signs and symptoms, and the radiologic appearance exists, as this may be the only red flag that allows their identification in the acute setting. An early and accurate diagnosis followed by prompt and more aggressive treatment when necessary is mandatory for successful results. LEVEL OF EVIDENCE: Level IV-case series.

Importance of the Occipitoaxial Angle and Posterior Occipitocervical Angle in Occipitocervical Fusion.

OBJECTIVE: To observe the effects of occipitoaxial angle (O-C2 angle, OC2A) and posterior occipitocervical angle (POCA) selection on postoperative clinical efficacy and lower cervical curvature in patients with acute acquired atlantoaxial dislocation after occipitocervical fusion (OCF). METHODS: A total of 150 healthy subjects without cervical disease (healthy group) were randomly selected based on gender and age. Three spine surgeons measured the OC2A and POCA of the healthy group and averaged the values. A total of 30 patients with an average age of 51.0 years (range, 18-70 years; 16 male and 14 female) with trauma or rheumatoid arthritis (disease group) who underwent occipitocervical fusion (OCF) for atlantoaxial dislocation between January 2012 and June 2016 were reviewed. OC2A, POCA, and cervical spinal angle (CSA) were measured postoperative/soon after surgery and ambulation, and at the final follow-up visit. The preoperative and final follow-up visual analog scale (VAS), Japanese orthopedics association score (JOA), neck disability index (NDI), and dCSA (change of CSA from postoperative/soon after surgery and ambulation to final follow-up) were recorded. RESULTS: The values of OC2A and POCA in 150 healthy subjects were 14.5° ± 3.7° and 108.2° ± 8.1°, respectively, and the 95% confidence interval (CI) were 7.2°-21.8° and 92.3°-124.0°, respectively. There was a negative correlation between OC2A and POCA (r = -0.386, P < 0.001). There were 18 patients (group one) of ideal OC2A and POCA (both within 95% CI of the healthy group) postoperative/soon after surgery and ambulation with a mean follow-up time of 26.3 ± 20.9 months in disease group. The remaining patients (group two) with a mean follow-up time of 31.3 ± 21.3 months. There was no statistically significant difference in the baseline data as well as pre-operative outcomes, including VAS score, JOA score, and NDI between the two groups. Likewise, the post-operative outcomes in final follow-up, including VAS and JOA score, had no distinct difference in the two groups. However, NDI (11.0 ± 2.9) in group two at the final follow-up was significantly higher than that in group one (7.0 ± 2.3) (P < 0.001). And group two showed statistically greater dCSA (5.9 ± 7.5°) than group one (-2.3° ± 6.2°) (P = 0.003). CONCLUSIONS: The negative correlation between OC2A and POCA plays an important role in maintaining the biodynamic balance of the occipital-cervical region. OC2A and POCA should be controlled of a normal population in patients with acute acquired atlantoaxial dislocation during OCF, which can further improve the clinical efficacy and prevent loss of lower cervical curvature after surgery.

Are Hooded, Crosslinked Polyethylene Liners Associated with a Reduced Risk of Revision After THA?

BACKGROUND: Hooded acetabular liners and head sizes ≥ 32 mm have both shown to have a beneficial effect on the revision rate for dislocation in THA. Experience with noncrosslinked polyethylene (nonXLPE) raised concerns regarding the risk of impingement damage, loosening, and osteolysis with hooded liners; however, the evidence for this in crosslinked polyethylene (XLPE) is inconclusive. The interaction between different femoral head sizes and hooded liners is not well understood, and it is unclear whether hooded XLPE liners have a beneficial effect on overall long-term survivorship. QUESTIONS/PURPOSES: We analyzed a large national joint registry to ask: (1) Is the use of hooded XLPE liners associated with a reduced revision rate for dislocation compared with nonhooded liners? (2) Is there a difference in the revision rate for aseptic loosening/osteolysis? (3) Is head size associated with any difference in the revision rate between hooded and nonhooded liners? METHODS: The Australian Orthopaedic Association National Joint Replacement Registry longitudinally maintains data on all primary and revision joint arthroplasties with nearly 100% capture. We analyzed all conventional primary THAs performed from registry inception in September 1999 until December 31, 2016 in patients with a diagnosis of osteoarthritis who had nonhooded or hooded XLPE bearings in a cementless acetabular shell. The study group included 192,659 THA procedures with XLPE liners, of which 67,904 were nonhooded and 124,755 were hooded. The mean age of patients receiving nonhooded liners was 70 years (range, 11-100 years); 44% were males. This was similar to the patients with hooded liners, who had a mean age of 70 years (range, 16-100 years); 45% were males. The main outcome measure was the cumulative percent revision at 15 years of the THA using Kaplan-Meier estimates of survivorship. We examined reasons for revision and and performed multivariable analysis to control for the confounding factors of three head size groups (< 32mm, 32mm, and > 32mm) and for the method of femoral fixation. RESULTS: There was a higher revision rate for dislocation for patients with nonhooded liners at all times to 15 years (HR, 1.31; 95% CI, 1.17-1.47; p < 0.001). There was a higher revision rate for the diagnosis of aseptic loosening/osteolysis with patients with nonhooded liners compared with hooded liners (HR, 1.19; 95% CI, 1.05-1.34; p = 0.006). Head sizes of 32 mm or larger were independently associated with a lower comparative revision rate between hooded and nonhooded liners, but this was not apparent for head sizes smaller than 32 mm. It appeared that the main driver of the finding in larger heads was a reduced dislocation risk with hooded liners for 32 mm heads (HR, 1.50; 95% CI, 1.23-1.80; p < 0.001) and for heads larger than 32 mm (HR, 1.50; 95% CI, 1.20-1.89; p < 0.001). CONCLUSIONS: Prior research has suggested that hooded acetabular liners may be associated with impingement, loosening, and osteolysis; however, in this large, registry-based report we found that XLPE hooded liners are not associated with an increased revision rate for aseptic loosening/osteolysis. Although there are many potential confounding variables in this registry analysis, if anything, surgeons using larger femoral heads and hooded liners likely did so in patients with a higher perceived dislocation risk. Patients with larger heads and XLPE hooded liners were, however, less likely to experience revision for dislocation. These liners therefore appear reasonable to use in primary THA at the surgeon's discretion. LEVEL OF EVIDENCE: Level III, therapeutic study.

Hip precautions not meaningful after hemiarthroplasty due to hip fracture. Cluster-randomized study of 394 patients operated with direct anterolateral approach.

AIMS: We aimed to compare two treatment regimes, one with and one without postoperative precautions in hemiarthroplasty patients, in terms of dislocation rate and patient-reported outcome. Direct lateral approach was used. PATIENTS AND METHODS: 394 patients were included in a cluster-randomized study 2010-2014. Depending on which ward they were admitted to, they were allotted to free rehabilitation (non-precaution group, NPG, n = 226) or our conventional regime with precautions and mandatory assistive equipment (precaution group, PG, n = 168). Patients were followed during hospital stay, at 6 weeks (postal questionnaire), 3 month (visit) and 6 months (reading of medical records) by means of function tests, health-related quality of life (EQ-5D) and other patient-reported outcome measures (PROM). RESULTS: One patient in each group had dislocation(s). We found no statistically significant differences regarding in-hospital-mortality, severe adverse events, EQ5D index or other PROM. In the NPG, rehabilitation personnel had significantly shorter work effort during hospital stay (p < 0.001). 7 in the NPG and 13 of the PG had reoperations (p = 0.038), 4 and 8 had deep infections, 3 and 5 periprosthetic fractures. CONCLUSION: Rehabilitation precautions are not needed for preventing dislocation when direct lateral approach is used. Without precautions, rehabilitation personnel implement significantly shorter work effort during hospital. We found no statistically significant differences regarding PROM and complications except for somewhat more reoperations in total in the precaution group.

An increase in the risk of excessive femoral anteversion for relatively younger age and types of femoral morphology in total hip arthroplasty with direct anterior approach.

BACKGROUND: Direct anterior approach (DAA) is known to diminish a dislocation risk and widely used for total hip arthroplasty (THA). On the other hand, anterior dislocation due to increasing stem anteversion and cup anteversion is an important complication. METHODS: A retrospective analysis of 140 (male/female: 10/130) consecutive patients with 149 hips who had undergone primary THA in the period between 2011 and 2015 was conducted. Factors including age, gender, body mass index (BMI), and primary diagnosis were examined. Radiographic parameters including the Dorr proximal femoral types, cortical thickness index (CTI), canal flare index (CFI), and canal to calcar index were measured. To investigate relationships of combined anteversion (CA) with other factors, a stepwise regression analysis was performed. RESULTS: The mean age, BMI, and the follow-up period were 69.5 ± 10.3 years old, 23.4 ± 3.4 kg/m2, and 48.2 ± 13.6 months, respectively. The proximal femurs of the 149 hips were categorized as Dorr type A ( n = 33), type B ( n = 110), and type C ( n = 6). The mean CTI, CFI, and canal to calcar index were 0.56 ± 0.08, 4.15 ± 0.83, and 0.46 ± 0.09, respectively. The mean stem varus angle, radiographic inclination, and radiographic anteversion of the cup were 0.19 ± 1.63, 40.9 ± 6.0°, and 12.7 ± 3.5°, respectively. Stem anteversion measured by computed tomography (CT) axial image was 17.7 ± 12.0°. The mean radiographic inclination, radiographic anteversion (CTRA), and anatomical anteversion analyzed by Kyocera 3-D template were 40.8 ± 7.2°, 19.8 ± 6.6°, and 28.8 ± 10.0°, respectively. Mean CA defined as the sum of stem anteversion and CTRA was 37.5 ± 14.5°. To investigate relationships of CA with other factors, a stepwise regression analysis was performed and resulted in a model with age ( p < 0.001). In the same way, stem anteversion and CTRA were analyzed; only for the stem anteversion, the stepwise selection process resulted in a model with age ( p < 0.001) and the Dorr types ( p = 0.047). CONCLUSION: The risk of excessive femoral anteversion increases for relatively younger age and for types of femoral morphology according to the Dorr classification, moreover with an increase of CA in DAA-THA with cementless tapered-wedge stem.

In defence of the posterior malleolus.

The posterior malleolus of the ankle is the object of increasing attention, with considerable enthusiasm for CT scanning and surgical fixation, as expressed in a recent annotation in The Bone & Joint Journal. Undoubtedly, fractures with a large posterior malleolar fragment that allow posterior talar subluxation from the mortise are served better by fixation. However, in all other situations, the existing literature does not support this widespread change in practice. The available biomechanical evidence shows that the posterior malleolus has little part to play in the stability or contact stresses of the ankle joint. Radiographic studies have not shown that CT scanning offers helpful information on pathoanatomical classification, case selection, or prognosis, or that scanning improves the likelihood of an adequate surgical reduction. Clinical studies have not shown any improvement in patient outcome after surgical fixation, and have confirmed that the inevitable consequence of increased intervention is an increased rate of complications. A careful and thoughtful evaluation of indications, risks, and benefits of this fashionable concept is required to ensure that we are deploying valuable resources with efficacy, and that we do no harm. Cite this article: Bone Joint J 2018;100-B:566-9.

Prevention of Dislocation After Total Hip Arthroplasty.

BACKGROUND: Prevention of dislocation after primary total hip arthroplasty (THA) begins with patient preoperative assessment and planning. METHODS: We performed a literature search to assess historical perspectives and current strategies to prevent dislocation after primary THA. The search yielded 3458 articles, and 154 articles are presented. RESULTS: Extremes of age, body mass index >30 kg/m2, lumbosacral pathology, surgeon experience, and femoral head size influence dislocation rates after THA. There is mixed evidence regarding the effect of neuromuscular disease, sequelae of pediatric hip conditions, and surgical approach on THA instability. Sex, simultaneous bilateral THA, and restrictive postoperative precautions do not influence the dislocation rates of THA. Navigation, robotics, lipped liners, and dual-mobility acetabular components may improve dislocation rates. CONCLUSIONS: Risks for dislocation should be identified, and measures should be taken to mitigate the risk. Reliance on safe zones of acetabular component positioning is historical. We are in an era of bespoke THA surgery.

Do dual-mobility cups cemented into porous tantalum shells reduce the risk of dislocation after revision surgery?

Background and purpose - Dual-mobility cups (DMCs) reduce the risk of dislocation and porous tantalum (TM) shells show favorable osseointegration after acetabular revision surgery, yet the combination of these implants has not been studied. We hypothesized that (1) cementing a DMC into a TM shell decreases the risk of dislocation; (2) DMCs cemented into TM shells are not at greater risk of re-revision; (3) liberation of tantalum ions is marginal after use of this combined technique. Patients and methods - We investigated the outcome in 184 hips (184 patients) after acetabular revision surgery with TM shells, fitted either with DMCs (n = 69), or with standard poly-ethylene (PE) liners (n = 115). Chart follow-up was complete for all patients, and the occurrence of dislocations and re-revisions was recorded. 20 were deceased, 50 were unable to attend follow-up, leaving 114 for assessment of hip function after 4.9 (0.5-8.9) years, radiographs were obtained in 99, and tantalum concentrations in 84 patients. Results - 1 patient with a DMC had a dislocation, whereas 14 patients with PE liners experienced at least 1 dislocation. 11 of 15 re-revisions in the PE group were necessitated by dislocations, whereas none of the 2 re-revisions in the DMC group was performed for this reason. Hence, dislocation-free survival after 4 years was 99% (95% CI 96-100) in the DMC group, whereas it was 88% (CI 82-94, p = 0.01) in the PE group. We found no radiographic signs of implant failure in any patient. Mean tantalum concentrations were 0.1 µl/L (CI 0.05-0.2) in the DMC group and 0.1 µg/L (CI 0.05-0.2) in the PE group. Interpretation - Cementing DMCs into TM shells reduces the risk of dislocation after acetabular revision surgery without jeopardizing overall cup survival, and without enhancing tantalum release.

Afectación medular en la artritis reumatoide / Involvement of the spinal cord in rheumatoid arthritis

No disponible