Dislocation Group Research Articles

Strain hardening and stored energy in high-Mn austenitic based low-density steel

In the present study an attempt has been made to understand the high strain hardening in austenitic low-density steel using two full field measurements of temperature and strain on the sample during tensile deformation. Based on these measurements’ evolution of energy storage during deformation was calculated. High energy storage has been attributed to the interaction between dislocation groups belonging to different slip bands and destruction of short-range order (SRO) clusters. This in turn, dictates the range of the elastic stress field of slip bands. Furthermore, weak deformation heterogeneity ensued just after yield and continued with a fixed strain pattern up to facture. This did not result in macroscopic instability but manifested as microstructural heterogeneity in the form of micro-band and nano twins at later stages of deformation. A mathematical model of energy storage based on dislocation entrapment is discussed.

Preoperative radius head dislocation affects forearm rotation after mobilization of congenital radioulnar synostosis

BackgroundThe present study was carried out to answer three questions: 1) How much forearm rotation can be expected after mobilization of congenital radioulnar synostosis (CRUS)? 2) Does preoperative radius head dislocation affect forearm rotation after mobilization? 3) What factors other than radius head dislocation affect postoperative forearm rotation? MethodsWe performed mobilization of CRUS with a free vascularized fascio-fat graft and a radius osteotomy (Kanaya’s procedure) on 26 forearms of 25 patients. The age at the surgery ranged from 5.3 to 13.4 years. The follow-up duration ranged 24–111 months. We classified CRUS into 3 groups according to the dislocation of the radius head: posterior dislocation (N = 13), anterior dislocation (N = 9) and no dislocation (N = 4). Since major complaints of patients and parents were poor forearm rotation and lack of supination, they were evaluated separately. ResultsMean preoperative forearm ankylosis angle was 34.8° (range; neutral to 90° pronation). Preoperative pronation ankylosis angle was higher in the posterior dislocation group (mean 55.3°) than the anterior dislocation (mean 11.6°) and no dislocation groups (mean 5.0°). There was no re-ankylosis after mobilization and the mean postoperative active range of motion (ROM) was 86.5°. The mean active ROM was 75.7° in the posterior dislocation group, 96.1° in anterior dislocation group and 100.0° in no dislocation group. The mean active supination was 6.9, 33.9 and 47.5° respectively. The posterior dislocation group showed less ROM and less supination than other groups. Preoperative pronation ankylosis angle showed negative correlation with postoperative ROM (ρ = − 0.59) and postoperative supination (ρ = − 0.73). ConclusionThe mean postoperative active ROM of this mobilization was 86.5°. Posterior dislocation group showed higher pronation ankylosis angle preoperatively, and less postoperative ROM and less supination than anterior and no dislocation groups. Preoperative pronation ankylosis angle showed negative correlation with postoperative ROM and supination.

Topologically Closed Packed Phase and Its Interaction with Dislocation Movement in Ni–Based Superalloy during High–Temperature Creep

In superalloys, topologically close–packed (TCP) phases, which contain refractory elements, usually significantly influence the mechanical properties. The current work investigates the structure and composition of the TCP phase in an Al–Mo–rich Ni–based single crystal superalloy. It is shown that after 40 h of thermal exposure, a large number of strip–like TCP phases are formed, which are enriched in Mo and Re. The structure of the TCP phase is identified as the tetragonal σ phase with the lattice parameter a being 0.93 nm and c being 0.50 nm. During the creep process, the single crystal tilts obviously and leads to orientation variation from <1 1 0> direction. Two groups of dislocations are observed in the deformed sample. One group contains straight dislocation lines and another group contains dislocation networks. The interaction between TCP phase and dislocation in the single crystal superalloy is studied to reveal the effect of the TCP phase on the deformation behavior. During creep, the σ phase hinders the dislocation movement, which may contribute to the propagation of the cracks and the final fracture.

Risk factor investigation for hip dislocation after periacetabular tumour resection and endoprosthetic reconstruction via thin-slice CT-based 3D model

Dislocation of the hip remains a major complication after periacetabular tumour resection and endoprosthetic reconstruction. The position of the acetabular component is an important modifiable factor for surgeons in determining the risk of postoperative dislocation. We investigated the significance of horizontal, vertical, and sagittal displacement of the hip centre of rotation (COR) on postoperative dislocation using a CT-based 3D model, as well as other potential risk factors for dislocation. A total of 122 patients who underwent reconstruction following resection of periacetabular tumour between January 2011 and January 2020 were studied. The risk factors for dislocation were investigated with univariate and multivariate logistic regression analysis on patient-specific, resection-specific, and reconstruction-specific variables. The dislocation rate was 13.9% (n = 17). The hip COR was found to be significantly shifted anteriorly and inferiorly in most patients in the dislocation group compared with the non-dislocation group. Three independent risk factors were found to be related to dislocation: resection of gluteus medius (odds ratio (OR) 3.68 (95% confidence interval (CI) 1.24 to 19.70); p = 0.039), vertical shift of COR > 18 mm (OR 24.8 (95% CI 6.23 to 128.00); p = 0.001), and sagittal shift of COR > 20 mm (OR 6.22 (95% CI 1.33 to 32.2); p = 0.026). Among the 17 patients who dislocated, 70.3% (n = 12) were anterior dislocations. Three independent risk factors were identified, suggesting the importance of proper restoration of the COR and the role of the gluteus medius in maintaining hip joint stability.Cite this article: Bone Joint J2022;104-B(10):1180-1188.

Ten-year outcome following surgical treatment of femoroacetabular impingement

The primary aim of this study was to determine the ten-year outcome following surgical treatment for femoroacetabular impingement (FAI). We assessed whether the evolution of practice from open to arthroscopic techniques influenced outcomes and tested whether any patient, radiological, or surgical factors were associated with outcome. Prospectively collected data of a consecutive single-surgeon cohort, operated for FAI between January 2005 and January 2015, were retrospectively studied. The cohort comprised 393 hips (365 patients; 71% male (n = 278)), with a mean age of 34.5 years (SD 10.0). Over the study period, techniques evolved from open surgical dislocation (n = 94) to a combined arthroscopy-Hueter technique (HA + Hueter; n = 61) to a pure arthroscopic technique (HA; n = 238). Outcome measures of interest included modes of failures, complications, reoperation, and patient-reported outcome measures (PROMs). Demographic, radiological, and surgical factors were tested for possible association with outcome. At a mean follow-up of 7.5 years (SD 2.5), there were 43 failures in 38 hips (9.7%), with 35 hips (8.9%) having one failure mode, one hip (0.25%) having two failure modes, and two hips (0.5%) having three failure modes. The five- and ten-year hip joint preservation rates were 94.1% (SD 1.2%; 95% confidence interval (CI) 91.8 to 96.4) and 90.4% (SD 1.7%; 95% CI 87.1 to 93.7), respectively. Inferior survivorship was detected in the surgical dislocation group. Age at surgery, Tönnis grade, cartilage damage, and absence of rim-trimming were associated with improved preservation rates. Only Tönnis grade was an independent predictor of hip preservation. All PROMs improved postoperatively. Factors associated with improvement in PROMs included higher lateral centre-edge and α angles, and lower retroversion index and BMI. FAI surgery provides lasting improvement in function and a joint preservation rate of 90.4% at ten years. The evolution of practice was not associated with inferior outcome. Since degree of arthritis is the primary predictor of outcome, improved awareness and screening may lead to prompt intervention and better outcomes.Cite this article: Bone Jt Open2022;3(10):804-814.

TREATMENT RESULTS OF PATIENTS WITH FRACTURE-DISLOCATION OF THE FOREARM BONES

Purpose of the study: to analyze the treatment results of fracture dislocations of the forearm bones.
 Materials and research methods. In the traumatology department of the KP “Dnepropetrovsk Regional Clinical Hospital named after I.I. Mechnikov "DOR" 63 patients with fracture dislocations of the proximal forearm bones has been trested from 2016 to 2020. Taking into account the peculiarities of damage to the stability components of the elbow joint, all patients were divided into 3 groups depending on the type of damage to various anatomical stabilizers of the elbow joint: dislocation fractures of the Monteggi type, fractures of Malgene dislocation (through-olecranial fractures), “terrible triad”.
 Results. In the Monteggi fracture dislocation group (n = 24), excellent and good long-term functional results in 16.7% and 45.8% of patients, respectively, satisfactory - in 20.8% and unsatisfactory - in 16.7%. In the Malgeny fracture dislocation group, the majority of patients had excellent and good results - 14 (87.5%), satisfactory - in 2 (12.5%), there were no unsatisfactory results. In the group "terrible triad of the elbow joint" excellent results were obtained in 3 cases (15.8%), good - in 7 (36.8%), satisfactory - in 4 (21.1%), and unsatisfactory - in 5 (26 , 3%).
 Conclusions. Stable-functional osteosynthesis with the restoration of bone and soft tissue stabilizers of the elbow joint, with the possibility of active early restoration of the function of the elbow joint, help to reduce the period of disability and give positive results in 84.7% of patients.

Residual Hip Dysplasia in Children With Unilateral Hip Dislocation-Does Side Matter?

Developmental dysplasia of the hip (DDH) is the most common musculoskeletal abnormality in infants and young children. Despite the fact that the left hip is most frequently affected, literature and clinical experience suggest a poorer outcome for right-sided hip dislocation in DDH. On the basis of this hypothesis, we studied the outcomes (residual dysplasia, number of surgeries, and complication rate) of right-sided unilateral hip dislocation in comparison with left-sided unilateral hip dislocation in DDH up to 8 years follow-up. We identified all patients with unilateral hip dislocation at Erasmus MC Sophia Children's Hospital from 2002 to 2012, diagnosed with DDH before the age of 1 year and with a minimum follow-up of 8 years. The primary outcome was residual dysplasia (based on an acetabular index (AI) >18 degrees and center-edge angle of Wiberg (CEA) <15 degrees) at the age of 8 years. Secondary outcome measures were residual dysplasia at the ages of 1, 2, and 5 years, successful surgical reduction rates, additional surgery, and complication rates. Out of a consecutive series of 555 patients, 298 could be included (17 males; median age at diagnosis 4.0 [IQR 3.0 to 5.5] months): 107 patients (35.9%) had right-sided unilateral hip dislocation. There was no significant difference in residual dysplasia between the unilateral left-sided and unilateral right-sided hip dislocation groups, respectively, at 1-year follow-up (34.0% vs. 24.2%, P =0.107), 2-year follow-up (74.1% vs. 70.1%, P =0.565), 5-year follow-up (74.1% vs. 66.2%, P =0.261), and 8-year follow-up (65.3% vs. 53.8%, P =0.199). There was no significant difference in surgical interventions between the left-sided and right-sided hip dislocation groups, respectively: additional surgical reduction (14.7% vs. 15.0%, P =0.945) and additional surgery for residual dysplasia (8.9% vs. 10.3%, P =0.695). There was no significant difference in complication rate between the unilateral left-sided and unilateral right-sided hip dislocation groups, respectively: avascular necrosis (19.4% vs. 15.9%, P =0.454) and redislocation (11.5% vs. 9.3%, P =0.561). The results of our study suggest that in patients with DDH, unilateral right-sided hip dislocation does not have poorer outcomes compared with unilateral left-sided hip dislocation during an 8-year follow-up. Level III - retrospective follow-up study.

Expression and distribution pattern of aggrecanases and miR-140s in the thickened synovia of shoulder joints in rotator cuff tears: A retrospective observational study.

The rotator cuff (RC) is frequently torn at the enthesis composed of fibrocartilage. We aimed to histopathologically evaluate lining layers and assess the distribution of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)4, ADAMTS5, and microRNA (miR)-140s in the synovia of patients with RC tears. We recruited 51 patients who underwent arthroscopic surgical treatment for full-thickness rotator cuff tears, including 26 patients with < 3 cm tear size (group N) and 25 patients with ≥ 3 cm tear size (group W). Biopsied synovia were analyzed using histological and immunohistological techniques for the presence ADAMTS4 and ADAMTS5. The layers of the synovial lining were morphologically classified into 3 grades according to the synovitis score and staining levels of ADAMTSs. The glenohumeral synovia from 8 patients with recurrent shoulder dislocation (group C) were used as controls. Furthermore, in situ hybridization was performed to evaluate the presence of miR-140s in patients with massive tears and recurrent shoulder dislocation. The staining levels were evaluated and analyzed based on comparison between patient groups and correlation between ADAMTS5 and miR-140s. Histological analysis revealed significant differences between groups W and C. ADAMTS5 and ADAMTS4 were strongly expressed in the synovial lining of patients in group W, and this expression was significantly higher than that in groups C and N. In addition, expression of ADAMTS5 was inversely correlated with that of miR-140-3p. This study showed that synovia from group W had a significantly higher rate of severely thickened areas with strong expression of both aggrecanases. Furthermore, the area with weak expression of miR-140-3p showed strong ADAMTS5 expression.

A Case Series on Whether Arthroscopic Bankart Repair Following Primary Traumatic Anterior Shoulder Dislocation or Recurrent Dislocation in Soldiers Has an Effect on the Postoperative Recurrence Rate.

BackgroundAnterior traumatic shoulder dislocation is very common among soldiers or any young population following injury, which is invariably treated by closed reduction. The dislocation when treated nonsurgically has a 71% high rate of recurrence. There is not much data available on the rate of recurrence when primary dislocation (first time) was treated by arthroscopic Bankart repair and in those who have recurrent (multiple) dislocations before surgery.AimThis study aims to report the postoperative recurrence rate in soldiers with first-time dislocation versus those with recurrent dislocations before surgery.Study designThe present study is a level IV case series treatment study.MethodsIn this prospective study, 143 soldiers were included, of which 82 patients had first-time dislocation (F group) and 61 patients had recurrent dislocation before surgery (R group). The patients were evaluated and followed up for over three years. Nonabsorbable PEEK suture anchors (Chetan Meditech, India) were used for arthroscopic Bankart repair. The recurrence rates, Rowe scores, visual analog scale (VAS) scores, subjective shoulder values (SSVs), and satisfaction were compared. We also used the Simple Shoulder Test (SST) score for evaluation. The scores were recorded preoperatively and at three-year follow-up. The range of motion, postoperative function, recurrence rates, and return to pre-injury state was evaluated.ResultsA total of 143 patients were included, providing 97.3% follow-up at an average of 36 months. The postoperative recurrence rate was 19.7% in the F group and 58.3% in the R group (P < 0.001). The odds of postoperative recurrence were five times higher in the recurrent dislocation group (odds ratio (OR): 5.23).ConclusionPatients who underwent repair after first-time dislocation show a lower postoperative recurrence rate as compared with those who had multiple dislocations before surgery. It is prudent to advise early repair even after the first dislocation especially in young active soldiers to reduce the risk of postoperative recurrence.

Coronal Movement during Flexion and Extension of Knee Joints.

Objective There are variabilities in the distance between the tibial tuberosity and the trochlear groove. The knee angle needs to be considered when talking about patellofemoral instability. Methods This retrospective study analyses the MRI images of knee angles from 0 and 30 degrees in the patella dislocation group (20 cases) and in the control group (20 cases) from Dec 2017 to Dec 2019. Two experienced orthopedic physicians separately measure the study with a blind experiment method. Results The TT-TG data of the patella dislocation group and control group are 17.88 ± 3.40 mm and 13.31 ± 3.01 mm when the knee angle is 0, which indicates a difference with statistical significance (P < 0.01). The TT-TG data of the patella dislocation group and control group are 11.51 ± 3.60 mm and 7.40 ± 1.93 mm when the knee angle is at 30 degrees, indicating a statistically significant difference (P < 0.01). Also, the TT-TG data of both the patella dislocation group and control group have statistically significant differences within different knee angles of the same group (P < 0.01). The differences of TT-TG are 6.36 ± 2.43 mm and 5.92 ± 1.65 mm when the knee angle changes from 0 to 30, which shows no statistically significant difference (P > 0.01). Conclusion This research initially obtained the relevant MRI data of the TT-TG distance from different knee angles between the Chinese patella dislocation patient group and control group. The study received a new criterion to evaluate the TT-TG of patients with patella dislocations when the knee angle is below 30 degrees. The knee flexion angles need to be considered to measure the TT-TG distance when comprehensively evaluating patellofemoral instability. The TT-TG distance gradually increases when the knee changes from flexion to extension. The difference of the TT-TG distances shows no statistically significant difference.

Poster 152: Arthroscopic Bankart Repair Following a Second Dislocation Results in Increased Failure Rates Compared to Immediate Repair After Following a Traumatic First Time Dislocation

Objectives:Many surgeons will consider nonoperative treatment following a 1st time dislocation and will consider operative management if a second instability event occurs particularly for the in season athlete. The objective of this study was to compare rates of recurrent dislocation and post-surgical outcomes in patients undergoing arthroscopic bankart repair for anterior shoulder instability immediately following a 1st time traumatic anterior dislocation versus patients who sustained a 2nd dislocation event following initial conservative management. We hypothesized that patients sustaining a 2nd anterior shoulder dislocation would be more at risk for recurrent dislocations after arthroscopic repair and secondarily, would have worse objective and subjective outcomes.Methods:This was a retrospective chart review identifying all patients undergoing primary arthroscopic surgical stabilization for anterior shoulder instability between 2013-2019 at a single academic institution. Demographics, clinical history, physical exam, imaging, operative details, and postoperative course was reviewed. Patients were eligible for inclusion if they underwent arthroscopic Bankart repair without remplissage sustained one or two dislocation events and were clinically followed for a minimum of 12 months postoperatively. Exclusion criteria included posterior instability, multidirectional instability, and previous stabilization surgery, Primary outcome was documentation of recurrent shoulder dislocation during the postoperative period. Secondary clinical outcome measures were assessed including need for revision surgery, need for manipulation under anesthesia (MUA), range of motion, strength, Subjective Shoulder Value (SSV), Visual Analog Scale (VAS), PROMIS mental and physical health, American Shoulder and Elbow Surgeons Shoulder Score (ASES), and Brophy shoulder activity scores.Results:A series of 89 patients (mean age 21.3 years ± 7.3 years) met criteria for inclusion. 72 shoulders underwent surgical stabilization after a single shoulder dislocation event and 17 underwent surgery after sustaining two documented shoulder dislocations. No significant difference in demographic and radiographic characteristics, including presence of bony Bankart and off-track Hill Sachs lesions, was present between the groups. The rate of recurrent dislocation was significantly higher in the multiple dislocation group compared to single dislocations (31% vs 12%, p=0.048). There was a trend toward increased rate of revision stabilization in the 2nd dislocation group which did not reach statistical significance (22% vs 58%, p=0.167). No significant difference was present in the need for revision surgery, need for MUA, conversion to Latarjet procedure, range of motion, supraspinatus strength, VAS, PROMIS, ASES, and Brophy scores between the groups.Conclusions:Immediate surgical stabilization following a 1st time dislocation significantly diminishes the risk of recurrent dislocation in comparison to those who undergo surgery following two dislocation events. These findings suggest that patients who return to activities after a primary anterior shoulder dislocation and undergo surgical stabilization following just one additional event are at increased risk of failure following surgery. Furthermore, patients who have sustained even one additional dislocation from the primary event may benefit from more aggressive approaches may be necessary including arthroscopic approaches with augmentation or open approaches. Despite differences in recurrence rates, both groups achieved excellent subjective functional outcomes at a minimum of 12 months after surgery.

Measurement of external deviation angle of patellar tendon and its application on diagnosis of recurrent patellar dislocation

To compare computed tomography (CT) measurement results of external deviation angle of patellar tendon and tibia tubercle-trochlea groove (TT-TG), as well as the diagnostic ability and pathology in recurrent patellar dislocation threshold. From January 2015 to March 2020, 46 patients with recurrent patella dislocation and 112 patients with non-patella dislocation were retrospectively analyzed. Forty-six patients with recurrent patella dislocation were divived into 2 groups according to TT-TG value, 11 patients with patellar dislocation with TT-TG≥20 mm(group A), including 7 males and 4 females, aged from 16 to 27 years old with an average of(21.00±3.98) years old; 35 patients with patellar dislocation with TT-TG<20 mm(group B), including 14 males and 21 females, aged from 16 to 37 years old with an average of(22.83±6.09) years old. While 112 patients with non-patella dislocation(group C) included 63 males and 49 females, aged 16 to 36 years old with an average of(22.87±5.69) years old. The measurement data of external deviation angle of patellar tendon and TT-TG value among three groups were compared. Spearman analysis was used to analyze correlation among them. Intraclass correlation coefficient (ICC) was used to determine repeatability within group. Receiver operating characteristic (ROC) area under the curve was used to evaluate diagnostic ability of parameters, and calculate osteotomy parameters of external deviation angle of patellar tendon, as well as external deviation angle of patellar tendon and TT-TG value in the diagnosis of recurrent patella diagnostic parameters of dislocation. External deviation angle of patellar tendon in group A, B and C was (22.04±3.09)°, (17.20±4.43)°and (10.22±3.45)° respectively;while TT-TG value was(21.15±0.71) mm, (15.97±2.69) mm and (11.12±3.77) mm, there were significance among three groups (P<0.01), and had difference between group A and B(P<0.01). There was strong positive correlation between external deviation angle of patellar tendon and TT-TG value (r=0.735, P<0.000 1). The intra-group ICC value(0.980, 0.982) of external deviation angle of patellar tendon in group A and B have better repeatability than TT-TG value (0.594, 0.775). The external deviation angle of patellar tendon in group C(0.956) and repeatability of TT-TG value(0.906) was very good. In the diagnosis of recurrent patellar dislocation, the area under ROC curve of external deviation angle of patellar tendon (0.916) was greater than TT-TG value(0.886), and diagnostic parameters were 13.84°and 14.69 mm, respectively;in tibial osteotomy, the area under ROC curve of external deviation angle of patellar tendon was 0.821, and osteotomy parameter was 20.15°. CT imaging could reliably measure external deviation angle of patellar tendon.There is a strong positive correlation between external deviation angle of patellar tendon and value of TT-TG, which could be used to determine pathological state of recurrent patellar dislocation, and external deviation angle of patellar tendon is superior to the TT-TG value in the diagnosis of recurrent patellar dislocation. The external deviation angle of patellar tendon could also be used to guide the formulation of the tibial osteotomy plan for recurrent patellar dislocation.

Are There Cephalometric Measurements Associated With Recurrent Temporomandibular Joint Dislocation?

Several theories have been proposed for the etiology of recurrent temporomandibular joint (TMJ) dislocation. The purpose of the present study was to determine whether there are cephalometric measurements associated with this phenomenon. A retrospective case-control study was performed, which included individuals who suffered from recurrent TMJ dislocation and a control group composed of patients who suffered from unrelated odontogenic infections and did not have any TMJ disorder. All the patients were referred to the Department of Oral and Maxillofacial Surgery at the Hadassah Medical Center between 2010 and 2021 and underwent multidetector computed tomography of the jaws. The main predictor variable was a history of recurrent TMJ dislocations. Covariates included age and gender. The primary outcome variable was a set of 11 cephalometric measurements. A statistical analysis was performed with the Mann-Whitney U-test for continuous variables and the Chi-squared test or Fisher's exact test for categorical variables, followed by a logistic regression model. Multiple comparisons were made by using the Benjamini-Hochberg method. The total 32 subjects included in the analysis consisted of 16 patients presenting with bilateral recurrent TMJ dislocation and a control population of 16 patients. The mean age was 34.19±12.7years, 40.6% (n=13) were males, with no statistically significant differences between the groups. An increased overbite was detected in the TMJ dislocation group, whereas over-jet was greater among the control group, although not statistically significant. Skeletal ratio analysis showed that the TMJ dislocation group had a statistically significantly greater Articulare-Gonion length (46.96mm±5.2mm vs 43.01mm±5.3mm; P=.043) and a lower angle of occlusal plane to Frankfort horizontal (4.56o±5.7o vs 9.60o ± 3.9o; P=.007), Y-axis (58.01o±4.9o vs 61.72o ± 3.3o; P=.019), and Frankfurt mandibular plane (24.10o±6.1o vs 30.14o ± 4.7o; P=.004). Specific cephalometric measurements are associated with recurrent TMJ dislocation. The high Articulare-Gonion length and the low rates of occlusal plane to Frankfort horizontal angle, Y-axis, and Frankfurt mandibular plane found in the study population suggest that the resultant vertically oriented elevator muscles may be considered a predisposing factor for this phenomenon.

Long-Term Survivorship of Cemented and Uncemented Polyethylene Liner Exchange

BackgroundRevision surgery is usually required for complications associated with total hip arthroplasty (THA). Significant morbidity can be associated with revision THA and thus some may only revise the liner of the original metal back component if it is found to be well fixed. We compare the long-term survivorship of cemented and uncemented head-liner THA exchange surgeries and possible causes. MethodsBetween 2000 and 2018, we reviewed cases from our arthroplasty database who underwent THA revision for head-liner exchange. We stratified our cohort into 2 groups: cemented and uncemented liners. Patients were followed clinically and radiographically to determine survivorship of the exchanges for both cemented and uncemented liners. Implant survivorship was measured using a competing risk analysis considering death and patients lost to follow-up as competing risks. ResultsA total of 84 patients (85 hips) underwent head-liner exchange surgery during the study period (21 cemented and 64 uncemented liners). The mean follow-up time was 6.9 years, with 75.3% and 24.7% of patients having been revised due to non-dislocation and dislocation causes, respectively. Two cemented liners (9.5%) and 11 uncemented liners (17.2%) required revision. The survival analysis of all head-liner revision was 86.4% at 18 years. Survival estimates liner exchanges due to dislocation versus non-dislocation groups were 57.3% versus 82.7% respectively (P = .034). ConclusionThe present study shows improved survivorship of head-liner exchanges performed due to non-dislocation etiology compared to dislocation etiology, but no difference in survivorship between cemented and uncemented head-liner exchange. Level of EvidenceLevel III.

Anteroposterior pelvic radiograph is not sufficient to confirm hip reduction after conservative treatment of developmental dysplasia of the hip.

The purpose of this study was to investigate whether an anteroposterior pelvic radiograph alone is sufficient to confirm hip reduction after conservative treatment or whether MRI could be alternatively performed. A total of 133 children (145 hips) were enrolled. All children were examined by anteroposterior pelvic radiographs and MRI. Three experts interpreted anteroposterior pelvic radiographs and then verified these results on MRI. For patients with inconsistent results between anteroposterior pelvic radiographs and MRI, the continuity of Shenton's line and Calve's line was recorded, and the medial clear space of bilateral hips was measured for unilateral cases. There was complete agreement between the three experts in the interpretation of anteroposterior pelvic radiographs of 111 (76.55%) hips; there was disagreement in the remaining 34 hips, with two experts diagnosing satisfactory reduction in 13 hips and dislocation in 21 hips. Assuming that the judgment of two or more doctors on anteroposterior pelvic radiographs was taken as the final result, 17 hips (11.72%) were misjudged. There was no statistically significant difference between the actual in-position group and the actual dislocation group in terms of the continuity of Shenton's line ( P = 0.62) and Calve's line ( P = 0.10) and the medial clear space of bilateral hips ( P = 0.08). In children less than 1 year of age with developmental dysplasia of the hip treated conservatively, the use of anteroposterior pelvic radiographs alone to judge hip reduction might result in misdiagnosis and missed diagnosis. MRI could be alternatively used to detect hip reduction after conservative treatment, especially when the doctor was not familiar with ultrasound in the presence of plaster.

Comparison of Surgical Treatment Outcomes of Pediatric Medial Epicondyle Fractures With and Without Elbow Dislocation

The aim of this study was to compare surgical treatment outcomes of pediatric medial epicondyle fractures with and without elbow dislocation. A total of 139 patients (75 boys and 64 girls; mean ± SD age, 9.6 ± 3.3 years) who received surgical treatment for medial epicondyle fractures at the Children's Hospital of Nanjing Medical University from January 2012 to December 2018 were included in our study. There were 99 cases that had a medial epicondyle fracture alone (group A) and 40 cases had a concomitant elbow dislocation (group B). Pain, ulnar nerve palsy, and stability of the elbow joint were recorded. Robert's criteria was used to assess elbow function. The prevalence of ulnar nerve palsy was lower in group A compared to group B, both before and after surgery. More patients underwent ulnar nerve transposition in group B than in group A. The incidence of elbow valgus instability was higher in group B than in group A. At the final follow-up, all patients had achieved good radiographic restoration of the elbow joint. Clinical outcomes in group A, according to Robert's criteria, were better than those in groupB. Elbow dislocation was associated with poorer functional outcomes following surgical treatment of medial epicondyle fractures in children. Therapeutic IV.

Distalization of the Tibial Tubercle for Patellar Stabilization Combined With Medial Patellofemoral Ligament Reconstruction: Length of Distalization or Residual Patella Alta and its Affect on Outcome

Background: Previous research supports that distal translation of the tibial tubercle osteotomy (dTTO) for patients with recurrent lateral patellar dislocation (R-LPD) and patella alta is effective for surgical patellar stabilization. Hypothesis/Purpose: The main purpose of this article is to evaluate (1) the results of modifying the surgical threshold and postoperative goal of patellar height measurements for surgical stabilization originated in the “menu à la carte” approach to patellar surgical stabilization and (2) the relationship between the distance distalized in millimeters and postoperative complications. Our hypothesis was that dTTO with medial patellofemoral ligament reconstruction (MPFL-R) will successfully stabilize the patella with improvement in outcome scores and few complications, using a modification of the original menu à la carte as our surgical algorithm. Study Design: Case series; Level of evidence, 4. Methods: A total of 68 consecutive patients with R-LPD underwent dTTO and MPFL-R for surgical patellar stabilization by a single surgeon between May 2009 and September 2015. Surgical indications were R-LPD combined with patella alta. The surgical threshold for dTTO was Caton-Deschamps index (CDI) or Insall-Salvati ratio ≥1.4 and/or a patellar trochlear index <0.15. The postoperative surgical goal for patellar height was a CDI of 1.1 to 1.2. Length of the distalization was computed by using the CDI measurement as the primary intraoperative guide and measured intraoperatively with a ruler. Clinical, radiographic, and patient outcome measures were reviewed. Results: The mean CDI preoperatively was 1.40 and postoperatively it was 1.09. The mean distalization was 9.9 mm (range, 4-15 mm). Three patients (4.4%) had frank R-LPD postoperatively. Ten patients had residual patella alta (CDI >1.2), with 1 redislocation. Mean postoperative CDI in the recurrent dislocation group was 1.13 (range, 1.06-1.25) as compared with 1.09 (range, 0.92-1.35) in the nonrecurrent group (P = 0.65). Complications included 3 tibial fractures (4.4%) and postoperative knee arthrofibrosis in 6 patients (8.8%), with mean distalization greater in the arthrofibrosis group (P = .04). Knee injury and Osteoarthritis Outcome Score (KOOS) values improved in all domains, including a 31–point increase in Quality of Life. Conclusion: dTTO with MPFL-R for patients with patella alta leads to a high rate of normalization of patellar height measurements (87%) and patellar stabilization (95.6%). Residual patella alta is not associated with an increased risk of recurrence. The length of dTTO up to 15 mm is not associated with an increase in postoperative complications, except for an increased prevalence of arthrofibrosis (8.8%).

Factors associated with dislocation after bipolar hemiarthroplasty through an (antero-)lateral approach in elderly patients with a femoral neck fracture: a retrospective cohort study with a nested case–control subanalysis of radiographic parameters

IntroductionDislocations of hip hemiarthroplasty (HHA) are serious complications. The aim of the study was to identify clinical aspects and radiographic parameters of the hip that put patients at risk for dislocation after HHA for femoral neck fractures.MethodsThis retrospective analysis included elderly patients with a femoral neck fracture treated with a HHA. A lateral (90.7%) and an anterolateral (9.3%) approach was applied. On pelvic radiographs, a nested-controlled analysis was performed. Two control patients were matched to one patient suffering a dislocation with respect to age, sex, and body-mass-index (BMI).ResultsIn 527 HHA, 10 dislocations (1.9%) were identified. In the dislocation group (DG), all patients were female (100% vs. 73.5%, p = 0.071). No significant differences between the DG and the control group (CG) were found with respect to age, body-mass-index (BMI), ASA Score, routine laboratory parameters, and comorbidity. Radiographic analysis revealed a smaller center edge angle (CEA, 39.0, IQR 33.0–42.5 vs. 43.0, IQR 41.0–46.0, p = 0.013), a more varus neck-shaft angle (NSA, 130.0, IQR 125.8–133.5 vs. 135.0, IQR 134.0–137.0, p = 0.011) of the contralateral side and a higher femoral head extrusion index (FHEI) in the DG (FHEI, 11.5, IQR 9.8–16.3 vs. 2.0 IQR 0.0–9.0, p = 0.003). In addition, a greater trochanteric fracture was associated with an increased likelihood for HHA dislocations (30.0% vs 6.0%, p = 0.022).ConclusionA smaller radiographic center edge angle, a more varus neck-shaft angle of the contralateral side, a higher femoral head extrusion index and intraoperative fractures of the greater trochanter are associated with an increased risk of HHA dislocation.

The influence of spinopelvic relationships on late dislocation of the prosthetic femoral head after total hip arthroplasty

Objective. To analyze the influence of sagittal balance parameters on the risk of dislocations of the head of the femoral component of the hip joint endoprosthesis.Material and Methods. A retrospective analysis of medical records of 113 patients with idiopathic coxarthrosis who underwent unilateral total hip arthroplasty was performed. The study assessed the parameters characterizing the sagittal balance in patients without prosthetic femoral head dislocation in the postoperative period (Group 1; n = 60) and in patients treated for prosthetic femoral head dislocation (Group 2; n = 53). Comparison of indicators was carried out by non-parametric Mann – Whitney U-test, and identification of dislocation predictors – by building single- and multi-factor logistic regression models. Differences were considered statistically significant at the achieved significance level p &lt; 0.05.Results. In Group 1, the type 3 sagittal balance according to Roussouly prevailed (48 %), in Group 2 – types 1, 2 and 4 (75 %). In patients with types 1 and 2 sagittal balance, the dislocations of the prosthetic femoral head occured 1.84 times more often than in patients with type 3, and that in patients with type 4 – 1.66 times more often.Conclusion. Patients with Roussouly type 3 sagittal balance have significantly lower risks of postoperative dislocation of the prosthetic femoral head, as compared with those with types 1, 2 and 4.

Evaluation of the rate of post-operative dislocation in patients with ipsilateral valgus knee deformity after primary total hip arthroplasty.

There is scant literature on the evaluation of dislocation after total hip arthroplasty (THA) in patients with ipsilateral valgus knee deformity. This study aimed to investigate the post-operative dislocation rate in patients with valgus knee deformity who underwent ipsilateral THA and identify whether ipsilateral valgus knee deformity increases the dislocation rate after THA. We retrospectively reviewed patients with valgus knee deformity who underwent ipsilateral THA in our institution from January 2016 to December 2018. Each hip with ipsilateral valgus knee deformity was matched with a hip without valgus knee deformity according to sex, affected side, and date of surgery. The primary outcome was the dislocation rate after THA. Univariate analyses were initially used to compare data between the dislocation group and the non-dislocation group. Independent risk factors for dislocation were determined using multivariate logistic regression. There were 257 THAs with ipsilateral valgus knee deformity (valgus knee group) and 257 THAs without valgus knee deformity (control group). The valgus knee group showed a significantly higher dislocation rate than the control group (9.7% versus 1.6%, p < 0.001). Older age (p = 0.020) and malposition of the acetabular cup (p = 0.048) were independent risk factors of post-operative dislocation. Patients with valgus knee deformity have a higher risk of dislocation after ipsilateral THA. If ipsilateral THA and total knee arthroplasty must be performed successively, total knee arthroplasty may have an earlier priority than THA.