Dislocation Group Research Articles

ANTERIOR CRUCIATE LIGAMENT RUPTURE DISGUISED AS PATELLAR INSTABILITY: A COMMON MISS

Patellar dislocation is a common presentation with a clear management pathway. Sometimes, however, what a patient experiences as the patella dislocating may, in fact, be ACL insufficiency.We reviewed case notes and imaging of 315 consecutive ACL reconstructions, collecting data on the date and mechanism of injury, time to MRI, and reconstruction. We noted cases initially diagnosed as patellar dislocation.25 of 315 (7.9%) patients were initially diagnosed with a patellar dislocation. Subsequently, however, MRI scans revealed no evidence of patellar dislocation and instead showed ACL rupture with pathognomonic pivot-shift bony oedema. The false patella dislocation group were 32% female and had an average age of 25; the rest of the group average age was 27.1 and there were a lower proportion of females; 21%. The false patella instability patients had a median waiting time of 412 days from injury to operation (range: 70-2445 days), compared to 392 days (range: 9 – 4212 days) for rest of the patients. 5 of the remaining 290 had MRIs showing patella oedema with medial patello-femoral ligament injury in addition to their ACL rupture.From our literature search this is a new finding which shows that ACL rupture can present with symptoms suggestive of patellar dislocation. These findings raise the risk that there are a group of people who have been diagnosed with patellar instability who instead have ACL insufficiency and so are at risk of meniscal and chondral damage. Further research should analyse those diagnosed with patellar instability to quantify missed ACL injuries.

Patient Characteristics Influencing Knee Injury and Osteoarthritis Outcome Scores Vary with Time from Patellar Dislocation and Number of Dislocations

ObjectivesDemographic characteristics of the patient population influence patient reported outcome measures (PROMs) following patellar dislocations. The time from injury and number of dislocations can also vary within the patient population. The hypothesis of the study is that characteristics of the patient population influencing Knee injury and Osteoarthritis Outcome Score (KOOS) measures of pain, function and quality of life vary with time from patellar dislocation and number of dislocations. MethodsOutcome scores were evaluated for subjects in four groups: within five months of a first patellar dislocation (first-time group, n = 24), within five months of a recurrent dislocation (multiple group, n = 15), five to twelve months after a first dislocation (post-acute group, n = 14), and two years or longer after a first dislocation (two years group, n = 14). For each group, KOOS pain, physical function and quality of life scores were compared between males and females. KOOS scores were also correlated against age, body mass index (BMI), and time since first and most recent dislocation. ResultsFor the first-time dislocation group, physical function and quality of life scores were higher for men than women (p < 0.05). For the multiple dislocation group, pain and physical function improved as BMI decreased (p < 0.025), while quality of life improved as age decreased (p = 0.014). For the post-acute group, all three scores improved as BMI decreased (p < 0.05). For the two years group, all three scores worsened as time since first dislocation increased (p < 0.01). ConclusionsFollowing patellar dislocation, relationships between characteristics of the patient population and PROMs vary with time from injury and number of dislocations. In the acute phase following a first dislocation, PROMs likely reflect the traumatic injury. Based on relationships with BMI, outcomes likely reflect functional capacity of the knee in the acute phase of multiple dislocations and post-acute phase of a first dislocation. After multiple years, progressive degradation of the knee over time seems to influence PROMs. Level of EvidenceRetrospective study with more than one negative criterion (Level 4)

Habitual patellar dislocation exhibits less severe rotational deformities but poorer trochlear development and higher incidence of patella baja compared with recurrent patellar dislocation in skeletally mature patients.

This study compared the radiological characteristics between habitual and recurrent patellar dislocation in skeletally mature patients. From 2017 to 2019, 77 skeletally mature patients with habitual patellar dislocation were surgically treated at a single institution and reviewed retrospectively. A total of 55 knees from these patients were included in the habitual patellar dislocation group. During the same period, 55 knees with recurrent patellar dislocation were randomly selected from 242 patients and included in the recurrent patellar dislocation group. Various bony deformities were measured and compared between the two groups. Additionally, a subgroup analysis was conducted among patients with habitual patellar dislocation, comparing those with and without an 'invisible patella' observed on true lateral views with 30° of knee flexion. The femoral anteversion angle (21.8° vs. 26.3°, p = 0.041), tibiofemoral rotation angle (9.7° vs. 12.4°, p = 0.042) and external tibial rotation angle (24.3° vs. 29.6°, p = 0.001) in the habitual patellar dislocation group were significantly lower than those in the recurrent patellar dislocation group. 54% of knees in the habitual patellar dislocation group had a patella baja, and this was in sharp contrast to the recurrent patellar dislocation group in which none of the knees had a patella baja. 49.1% of knees in the habitual patellar dislocation group showed 'invisible patella' at 30° of knee flexion, and knees with 'invisible patella' had significantly higher tibial tubercle-trochlear groove (TT-TG) distance (30.4 vs. 19.8, p < 0.001) and tibiofemoral rotation angle (13.2° vs. 6.4°, p < 0.001) than knees with a visible patella. A distinct difference in bony anatomical features was observed between habitual and recurrent patellar dislocation in skeletally mature patients. Habitual patellar dislocation exhibited less severe rotational deformities of the lower extremity but showed poorer trochlear and patellar development, a larger TT-TG distance and a higher incidence of patella baja compared with recurrent patellar dislocation. Level III.

Influence of the type of atlantoaxial dislocation secondary to os odontoideum on sagittal alignment and balance of the subaxial cervical spine after posterior atlantoaxial fusion.

This retrospective study aims to investigate the effect of the type of atlantoaxial dislocation due to os odontoideum on the sagittal alignment and balance of the cervical spine after posterior atlantoaxial fusion. Data of 48 consecutive patients who underwent posterior C1-C2 fusion to treat atlantoaxial dislocation/instability due to os odontoideum were retrospectively reviewed. Radiographic variables, namely the T1 slope (T1S), C1-C2 angle, C2-C7 angle, C1-C2 sagittal vertical axis (SVA), C2-C7 SVA, and modified atlas-dens interval (MADI), were measured preoperatively, immediate postoperatively, and at final follow-up. Patients were divided into three groups based on the preoperative MADI. Differences within and between groups in radiographic variables and relationships between the investigated variables were analyzed. The MADI was correlated with the preoperative to postoperative changes in the C1-C2 angle (r = 0.776, P < 0.05) and C2-C7 angle (r = -0.357, P < 0.05). In the group with anterior atlantoaxial dislocation, the C1-C2 angle and C2-C7 SVA were significantly enlarged at final follow-up (P < 0.05), while the C2-C7 angle was significantly reduced (P < 0.05). The changes in C1-C2 angle and C2-C7 angle were opposite between the posterior group and the anterior dislocation group. The direction/type of atlantoaxial subluxation correlates with the changes in lower cervical curvature after atlantoaxial fusion. Patients with atlantoaxial posterior dislocation and atlantoaxial instability are less likely than those with atlantoaxial anterior dislocation to develop loss of lordosis after posterior atlantoaxial fusion.

Paper 35: Number of Patellar Dislocation Events are Associated with Increased Chondral Damage of the Trochlea: data from the JUPITER group

Objectives: Patellofemoral instability (PFI) is frequently associated with chondral injuries to the patella and trochlea. Though several radiographic and intra-operative studies have demonstrated a link between patellar dislocation and chondral injury, the influence of the number of patellar dislocation events on the presence of chondral wear and severity is not established. This study aimed to understand the association between the number of patellar instability events and chondral damage observed directly in a large patient population undergoing patellar stabilization procedures. Methods: This was a retrospective review of the prospective multi-center Justifying Patellar Instability Treatment by Results (JUPITER) cohort. All patients undergoing primary surgical procedures to address PFI from 12/2016 to 9/2022 with a recorded number of patellar dislocations and detailed intra-operative assessment of the articular cartilage were included. Cartilage lesions were classified using the International Cartilage Repair Society (ICRS) classification, where ICRS grades 2 to 4 are defined as abnormal or severely abnormal. The number of dislocation events was grouped into 1-2, 3-5, and &gt;5 dislocations. Continuous and categorical variables were compared using independent t-tests and chi-squared tests, respectively with multivariable regressions used to control for demographic characteristics potentially influencing cartilage wear. A significance threshold of p&lt;0.05 was used. Results: A total of 938 patients at mean age 16.2 ± 3.8 years (range 5.1-35.0 years, 61.4% female patients) undergoing PFI procedures were included. Of these, 580 (61.8%) demonstrated a chondral injury. The most commonly affected region was the patella (n = 498, 53.1%) followed by the femoral condyles (n = 148, 15.8%), and trochlea (n = 109, 11.6%), with 83 (8.8%) patients having lesions located on both the patella and trochlea (Table 1). MPFL reconstruction was performed in 861 (91.8%) cases (Table 2), with other commonly performed procedures including patellofemoral chondroplasty (n = 388, 41.4%) and lateral retinacular lengthening or release (n = 255, 27.2%). Patients with fewer dislocations more frequently underwent fixation of an osteochondral fragment (1-2: 19.5%, 3-5: 7.6%, &gt;5: 1.7%, p&lt;0.001). There were no differences in the presence (p=0.209) or grade (p=0.716) of patellar chondral lesions based on dislocation number (Table 3). Patients with &gt;5 patellar dislocations more frequently had a trochlear chondral lesion (19.8%) compared to the groups with fewer dislocations (1-2: 8.4%, 3-5: 13.0%, p&lt;0.001). A greater number of dislocations was also associated with a higher proportion of abnormal (ICRS grades 2-4) trochlear lesions (&gt;5: 15.3%, 3-5: 11.7%, 1-2: 7.6%, p=0.009), and the mean trochlear ICRS grade was significantly greater for the highest dislocator group (&gt;5, mean 0.45 ± 0.99, p=0.023) compared to those with fewer dislocations (1-2: mean 0.24 ± 0.84, 3-5: mean 0.34 ± 0.93). Combined patellar and trochlear lesions were also higher in the most frequent dislocation group (&gt;5 dislocations: 15.8%, 3-5: 9.9%, 1-2: 6.1%, p&lt;0.001). In multivariable regression accounting for age, sex, BMI, and dislocation count, a dislocation count &gt;5 was the only variable significantly predictive of the presence of a trochlear chondral lesion (OR 2.16, 95% CI 1.36-3.43, p=0.001). Both age in years (OR 1.11, 95% CI 1.06-1.16, p&lt;0.001) and BMI (OR 1.05, 95% CI 1.02-1.07, p&lt;0.001) were predictive of a patellar lesion, while both age in years (OR 1.07, 95% CI 1.01-1.13, p=0.017) and dislocation count &gt;5 (OR 2.25, 95% CI 1.35-3.75, p=0.002) were predictive of the presence of both a patellar and trochlear lesion. Conclusions: This study demonstrates that an increased number of patellofemoral dislocation events is associated with more frequent trochlear and combined patellar/trochlear chondral damage with higher injury severity. Specifically, a dislocation count &gt;5 is associated with a greater than 2-fold increase in the number of trochlear chondral injuries, which are of higher severity potentially requiring surgical management. Conversely, patients with fewer dislocation events were more likely to undergo osteochondral fracture fixation, which may have driven earlier operative intervention in this group. This is the first, large prospective study to demonstrate that multiple patellar dislocations can result in increased and more severe chondral damage.

Influences of deformation defects on etching behaviors of high-strength and high-conductivity Cu alloy for lead frame

With increasing integration of the semiconductor devices, the requirements on size accuracy and surface quality of the lead frame are higher. Cold-rolling and low-temperature aging are usually used in processing of the Cu alloy for lead frame, which generate/eliminate the deformation defects that affect the etched surface morphology and roughness, while the influence mechanisms have not been well revealed. In this study, the CuCrSn alloy was used as the experimental material, which was cold-rolled to different degree and then aged at 450 °C for different time, and the microstructures and etched surfaces of the specimens were characterized. The results show that etched surface morphologies of grains with different orientations in the coarse-grained Cu alloy are different. With increasing cold-rolling deformation, the influences of grain orientation become less obvious, and the dislocation groups on the slip planes result in grooves approximately parallel to the rolling direction, meanwhile the surface uniformity are improved and the surface roughness decreases. For the 80 % cold-rolled Cu alloy, the density of grooves decreases with increasing aging time and elimination of the dislocations, and the etched surface roughness decreases firstly and then tends to be stable. The etched surface changes significantly and the surface roughness increase obviously after recrystallization of the specimen.

Multivariate Analysis of Risk Factors for In-Hospital Dislocation Following Primary Total Hip Arthroplasty.

Background: Early dislocation following primary total hip arthroplasty (THA) is a rare but devastating complication and represents a source of patient morbidity and financial burden to the healthcare system. The objective of this study was to identify patient characteristics and comorbidities that are associated with increased early in-hospital dislocation rates following primary THA. Methods: A retrospective cohort study was conducted using patient data from the Nationwide Inpatient Sample (NIS) database; we identified patients who had undergone THA from 2016 to 2019 and compared those with an early periprosthetic dislocation prior to discharge to those without. The patient characteristics and comorbidities were compared using univariate analysis with a subsequent investigation of statistically significant variables using multivariate analysis. The variables were compared using chi square, Fisher's exact test, and independent sample t-tests with data assessed using odds ratio with 95% confidence intervals. Results: A total of 5151 patients sustained an early dislocation compared to 362,743 who did not. Those who sustained an in-hospital dislocation were more likely to share the following characteristics: female sex (OR 1.21, p < 0.01), age > 70 (OR 1.45, p < 0.01), Caucasian ethnicity (OR 1.22, p < 0.01), SLE (OR 1.87, p < 0.01), and Parkinson's disease (OR 1.93, p < 0.01). Certain characteristics were also associated with decreased odds of having an in-hospital dislocation including elective surgery (OR 0.14, p < 0.01), tobacco use (OR 0.8, p < 0.01), diabetes without complications (OR 0.87, p < 0.01), and a history of heart valve replacement (OR 0.81, p < 0.01). The length of stay was significantly longer (4.7 days vs. 2.3 days) as was the total hospital charges (USD $101,517 vs. USD $66,388) for the early in-hospital dislocation group. Conclusions: Several patient characteristics and comorbidities are associated with early in-hospital dislocation episodes following total hip arthroplasty including female sex, age > 70, non-elective surgery, SLE, and Parkinson's. This information may be useful to help guide intraoperative implant selection and/or postoperative protocol in select patient populations to limit early instability as well as decrease the financial burden associated with this postoperative complication.

Effects of lower limb length discrepancy on spinopelvic compensation following total hip arthroplasty in patients with developmental dysplasia of the hip

BackgroundLimited research has examined the impact of lower limb length discrepancy (LLLD) alteration on spinopelvic compensation in individuals with developmental dysplasia of the hip (DDH). This study aimed to investigate the effects of LLLD on spinopelvic compensation following total hip arthroplasty (THA) and elucidate the complex biomechanical adaptations in the spinopelvic structures.MethodsA retrospective review of DDH patients undergoing THA from January 2014 to December 2021 categorized individuals with Crowe type I and II into the low dislocation group (LDG, n = 94) and those with Crowe type III and IV into the high dislocation group (HDG, n = 43). Demographic data, as well as preoperative, postoperative, and last follow-up imaging data, including lower limb length (LLL), sacral obliquity (SO), iliac obliquity (IO), hip obliquity (HO), Cobb angle, apical vertebral translation (AVT), and coronal decompensation (CD), were collected for analysis.ResultsPatients in the LDG had a significantly higher surgical age and shorter disease duration (P<0.05). In LDG, patients exhibited substantial postoperative reductions in LLLD, SO, IO, and HO (P<0.05), while Cobb Angle, AVT, and CD showed no statistically significant changes (P>0.05). The variation in LLLD correlated significantly with the variations in SO, IO, and HO (P<0.05). Postoperative outcomes in the HDG demonstrated marked decreases in LLLD, SO, IO, HO, and CD (P<0.05), with no significant change in Cobb angle and AVT (P>0.05). The variation in LLLD correlated significantly with the variations in SO, IO, HO, and CD (P<0.05).ConclusionsTHA effectively reduces LLLD in patients with DDH, and the variation in LLLD correlates meaningfully with the recovery of spinopelvic compensatory mechanisms.

Dislocations deteriorate postoperative functional outcomes in supination-external rotation ankle fractures

PurposeTo assess the relationship between dislocation and functional outcomes in supination-external rotation (SER) ankle fractures. MethodsA retrospective case series study was performed on patients with ankle fractures treated surgically at a large trauma center from January 2015 to December 2021. The inclusion criteria were young and middle-aged patients of 18–65 years with SER ankle fractures that can be classified by Lauge-Hansen classification and underwent surgery at our trauma center. Exclusion criteria were serious life-threatening diseases, open fractures, fractures delayed for more than 3 weeks, fracture sites ≥2, etc. Then patients were divided into dislocation and no-dislocation groups. Patient demographics, injury characteristics, surgery-related outcomes, and postoperative functional outcomes were collected and analyzed. The functional outcomes of SER ankle fractures were assessed postoperatively at 1-year face-to-face follow-up using the foot and ankle outcome score (FAOS) and American orthopedic foot and ankle society score and by 2 experienced orthopedic physicians. Relevant data were analyzed using SPSS version 22.0 by Chi-square or t-test. ResultsDuring the study period, there were 371 ankle fractures. Among them, 190 (51.2%) were SER patterns with 69 (36.3%) combined with dislocations. Compared with the no-dislocation group, the dislocation group showed no statistically significant differences in gender, age composition, fracture type, preoperative complications with diabetes, smoking history, preoperative waiting time, operation time, and length of hospital stay (all p > 0.05), but a significantly higher Lauge-Hansen injury grade (p < 0.001) and syndesmotic screw fixation rate (p = 0.033). Moreover, the functional recovery was poorer, revealing a significantly lower FAOS in the sport/rec scale (p < 0.001). Subgroup analysis showed that among SER IV ankle fracture patients, FAOS was much lower in pain (p = 0.042) and sport/rec scales (p < 0.001) for those with dislocations. American orthopedic foot and ankle society score revealed no significant difference between dislocation and no-dislocation patients. ConclusionDislocation in SER ankle fractures suggests more severe injury and negatively affects functional recovery, mainly manifested as more pain and poorer motor function, especially in SER IV ankle cases.

Comparison of ultrasound-guided closed reduction and percutaneous pinning fixation for unstable humeral lateral condylar fractures.

Ultrasound-guided techniques have become popular in severe humeral lateral condylar fractures (HLCFs). This study compared the results of ultrasound-guided closed reduction and percutaneous pinning (UG-CRPP) for Song types 4 and 5 and dislocation type of HLCFs. This retrospective study was conducted in patients with HLCFs treated between January 2021 and October 2022 at three hospitals. The patients were divided into three groups according to Song's classification and elbow dislocation. The surgical time, reduction failure rate, and outcomes of the three groups were compared. The mean surgical time of the 94 patients across the three groups (Song 4 group, 42 cases; Song 5 group, 38 cases; and dislocation group, 14 cases) was the longest for Song 4 (66.14 ± 23.05 min), followed by the dislocation group (59.71 ± 21.07 min) and Song 5 (52.16 ± 14.94 min) (for all, P = 0.009). The failure rate decreased in the following order: dislocation group (5/14), Song 4 group (7/42), and Song 5 group (2/38). The failure rate of closed reduction in Song 4 was 3.2-fold higher than that in Song 5, and for the dislocation group, it was 7.6-fold higher than that in Song 5. Significant differences were observed between the Song 4, Song 5, and dislocation groups in terms of shaft-condylar angle and supination (P = 0.015, P = 0.043). No significant differences (P > 0.05) were observed in the carry angle, flexion, extension, or pronation of the three groups. Two cases of delayed healing, four cases of superficial infection, one case of trochlear necrosis, and 39 cases of lateral spur in the Song 4 group were observed. In the Song 5 group, five had a superficial infection, one had re-displacement, and 26 had a lateral spur. In the dislocation group, there were two cases of superficial infection and 10 of lateral spurs. Song 4 HLCFs require longer surgical time and present more postoperative complications than Song 5 and dislocation-type HLCFs and can easily lead to lateral spurs. The failure rates of closed reduction in Song 4 and the dislocation type were higher than those in Song 5. Thus, UG-CRPP can be used to treat patients with unstable HLCFs.

Clinical effects of combined anteversion and offset on postoperative dislocation in total hip arthroplasty

BackgroundImplant impingement and soft tissue tension are factors involved in dislocation after total hip arthroplasty (THA). Combined anteversion (CA) has been used as an indicator for implant placement. However, optimal implant placement remains a challenge. Moreover, the effect of changes in offset on dislocation is still unclear. In this study, we aimed to clarify the effects of postoperative CA and pre- and postoperative changes in offset on dislocation.MethodsIncluded were patients who underwent primary cementless THA between 2013 and 2020. The mean values of CA and offset in the dislocation and non-dislocation groups were compared. The CA values within ± 10% of the recommended values were defined as good CA, and those outside the range were rated as poor CA. The dislocation rates were compared between the good and poor CA groups and between the groups with and without increased offset.ResultsA total of 283 hips were included. The mean values of CA in the dislocation and non-dislocation groups were significantly different (P < 0.05). The dislocation rate was significantly lower in the good CA group (P < 0.05). The dislocation rates in the groups with and without increased total offset were 0.5% and 4.3%, respectively (P = 0.004). There were no dislocations in patients with good CA and increased offset.ConclusionsThe dislocation rate was significantly lower when implants were placed within ± 10% of the recommended CA value. Our results suggest that dislocation can be avoided by placing the implant in the good CA range and considering the increase in total offset on the operative side.

Influence of Etchants on Etched Surfaces of High-Strength and High-Conductivity Cu Alloy of Different Processing States.

With the continuous integration of semiconductor devices, the requirements of the size accuracy and surface quality of etched lead frames are stricter. The etchant is a key factor in the etching process and etched surface quality, while the effects of the difference in etchants on the etched surface morphology of Cu alloy have not been directly studied. In this study, aqua regia, acidic FeCl3 and two CuCl2 solutions were used as etchants, and different CuCrSn specimens were etched and characterized. The results show that the etching rate in aqua regia is high, and the grain orientation, grain boundary (GB) and dislocations have significant influences on the local etching rate. The preferential etching of some atomic planes forms steps between the grains with different orientations, and preferential etching around the GB and dislocation group forms grooves, resulting in high surface roughness. For the surfaces etched by the FeCl3 and CuCl2 etchants, the steps and grooves are blurred; thus, they are less rough. The CuCrSn alloy surface etched by the aqua regia is clean, with little Cr-rich particles, while high-density Cr-rich particles remain on the surfaces etched by the FeCl3 and CuCl2 etchants. For the same kind of etchant, the ion concentration can affect the etching mechanism, rate and the etched surface morphology.

Application direct anterior approach in pediatric femoral head and neck lesions

BackgroundFemoral neck is one of the high-risk areas for benign tumors and tumor-like lesions. Small range of lesions may also lead to pathological fracture, femoral head necrosis and other serious problems.PurposeTo investigate a new minimally invasive surgical approach to resect femoral head and neck lesions in children.Patients and methodsRetrospective study of 20 patients with femoral neck and femoral head lesions from February 2019 to March 2023 in our hospital. Among them, 14 were boys and 6 were girls, 17 were femoral neck lesions and 3 were femoral head lesions. The age of the patients ranged from 3.2 to 12.6 years, with a mean of 7.1 years. The patients were divided into group A and group B according to different surgical approaches; group A used the Smith-Peterson approach, Watson-Jones approach or surgical dislocation approach and group B used the DAA. Intra-operatively, incision length, operative time and blood loss were recorded in both groups. Group A consisted of 1 femoral head lesion and 8 femoral neck lesions, including 5 cases of bone cyst and 4 cases of eosinophilic granuloma. Group B consisted of 2 femoral head lesion and 9 femoral neck lesions. A total of 11 patients with different types of disease were included in group B, including bone cysts (3 cases), aneurysmal bone cysts (1 case), eosinophilic granulomas (6 cases), Kaposi's sarcoma (1 case).ResultsThe two groups of patients differed in terms of incision length (P < 0.05), operative blood loss (P < 0.05) and operative time (P < 0.05). At 6–48 months post-operatively, there were no significant differences in function and all patients had good hip function.ConclusionThe direct anterior approach is effective for resection of paediatric femoral head and neck lesions. It provides clear exposure of the surgical site, minimal trauma and does not compromise the integrity of the anterior musculature.Level of evidence: III.

Femoroacetabular Variations Are Predisposing Factors for Traumatic Posterior Hip Dislocation.

Although high-energy trauma mechanisms are generally considered to cause traumatic posterior hip dislocations, femoroacetabular variations are assumed to contribute to low-impact hip dislocations. Thus, the present study aimed to identify morphologic femoral and acetabular risk factors that may also contribute to posterior hip dislocations in high-energy trauma mechanisms. The acetabular and femoral morphology of 83 hips with a traumatic posterior dislocation following a high-energy trauma mechanism were analyzed and matched to a control group of 83 patients who sustained high-energy trauma without a hip injury. The lateral center-edge angle, acetabular index, acetabular depth/width ratio, cranial and central acetabular version angles, and the anterior and posterior acetabular sector angles were measured on computed tomography to quantify femoroacetabular impingement (FAI) morphology, acetabular version, and coverage. The caput-collum-diaphyseal angle and the alpha angles in the coronal and axial planes were measured to detect cam-type FAI deformity. A receiver operating characteristic curve was utilized to determine threshold values for an increased risk of hip dislocation. Acetabular retroversion and posterior acetabular undercoverage were significantly increased in patients with hip dislocations compared with controls (p < 0.001). The central acetabular version angle and posterior acetabular sector angle that indicated an increased risk of hip dislocation were ≤9° and ≤90°, respectively. Cam-type FAI deformity and coxa valga were significantly increased in the dislocation group (p < 0.001). The anterolateral alpha angle that indicated an increased dislocation risk was ≥47°. Acetabular retroversion, posterior acetabular undercoverage, and cam-type FAI morphology may be risk factors contributing to traumatic posterior hip dislocation in high-energy trauma mechanisms. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Résultats à long terme de l’arthroplastie totale dans les luxations congénitales de la hanche. Étude rétrospective des résultats avec 10 à 20 ans de recul

Introduction: The impact of bone deformities, previous surgeries, and the surgical technique in total hip arthroplasty (THA) for congenital dislocation of the hip (CDH) at a long-term has not been clearly defined yet. In this single-centre observational study we sought to assess patients undergoing THA due to osteoarthritis secondary to severe CDH with low or high dislocation ten- to 20-years after surgery. To determine this purpose, we assessed: 1) THA-related complications and reoperations; 2) the clinical outcome, patients´ satisfaction and radiological results; and 3) the possible risk factors for reoperation with particular attention to the surgical technique and the influence of prior surgeries.Hypothesis: We hypothesized that an anatomical reconstruction of the hip would decrease the reoperations rates in patients undergoing THA with severe CDH.Methods: Seventy-five patients (85 hips) operated between 1999 and 2012 at our large tertiary hospital were analyzed. Fifty-six hips were diagnosed as low dislocation (group 1) and 29 hips as high dislocation (group 2). The existence of prior surgeries was frequent: group 1, pelvic osteotomies 6 hips, femoral osteotomies 7, tectoplasty (shelf) 6, resection arthroplasty 1 and lowering of the greater trochanter 1; group 2 included pelvic osteotomies 10 hips, femoral osteotomies 10, and a femoral lengthening 2. The number of additional procedures during THA was: group 1 (19/56 (34%)), acetabular roof bone autograft 8 hips, acetabular medial wall autograft 2, hardware removal 6, extended femoral osteotomy 2, and a femoral shortening 1; group 2 (20/29 (69%)), acetabular bone autograft 12 hips, medial autograft 1, hardware removal 1, extended femoral osteotomy 2, and a femoral shortening 4 hips The clinical and the radiological analysis were compared in both groups for a minimum follow-up of ten years. Cox regression models were used to detect risk factors for reoperation.Results: Nine patients (13.8%) required reoperation for the following reasons: cup loosening (5 hips), periprosthetic femoral fracture (3) and stem loosening (1); seven had prior surgeries. The 12-year survival rate for reoperation for any reason was 96.3% (95% Confidence Interval (CI) 91.2-100) in group 1 and 75.7% (95% CI, 65.8-90.8) in group 2 (p=0.003). Patients with high dislocation (p=0.02, Hazard Ratio (HR): 6.25, 95% CI, 1.26-30.9) and those with an acetabular component inclination placed out of the target zone between 35º and 50º (p=0.03, HR: 4,27, 95% CI, 1.13-16.1) had a higher risk of reoperation.Discussion: An optimal placement of the acetabular component decreased the reoperation rates in patients undergoing THA for severe CDH. Hips with high dislocation and the existence of prior surgery can affect THA implantation.Level of Evidence: III; retrospective; comparative

Effectiveness comparison of ultrasound-guided closed reduction and Kirschner wire fixation for different unstable humeral lateralcondylar fractures of children

To compare the effectiveness of ultrasound-guided closed reduction and Kirschner wire fixation for different unstable humeral lateralcondylar fractures of children. The clinical data of 94 children with unstable humeral lateralcondylar fractures admitted to three medical centers between January 2021 and October 2022 were retrospectively analyzed. The children were divided into three groups according to the Song classification and whether the elbow joint was dislocated or not, including 42 cases of Song 4 type (group A), 38 cases of Song 5 type (group B), and 14 cases of elbow joint dislocation (group C). There was no significant difference in gender, age, side, cause of injury, and time from injury to operation among the three groups ( P>0.05). All children were treated with ultrasound-guided closed reduction and Kirschner wire fixation. The operation time and complications of the three groups were recorded and compared, and the failure of closed reduction was evaluated by ultrasound. X-ray examination was performed at last follow-up to measure the Baumann angle, condylar angle, carrying angle, and lateral osteophyte of the affected side; the extension, flexion, pronation, and supination range of motion of the affected elbow joint were measured; the function of the elbow joint was evaluated by Mayo score. The operation time in group A was significantly longer than that in groups B and C ( P<0.05). There were 7, 2, and 5 cases of closed reduction failure in groups A, B, and C, respectively, and there was no significant difference in the incidence of the closed reduction failure ( P>0.05). All patients were followed up 6-28 months, with an average of 15.7 months. There was no significant difference in the follow-up time among the three groups ( P>0.05). Complications: in group A, there were 2 cases of delayed union, 4 cases of needle tract infection, 1 case of trochlear necrosis, and 39 cases of lateral osteophyte; in group B, there was 1 case of malunion, 5 cases of needle tract infection, 1 case of redisplacement, and 26 cases of lateral osteophyte; in group C, there were 2 cases of needle tract infection and 10 cases of lateral osteophyte. There was no significant difference in the incidence of complications among the three groups ( P>0.05). No cubitus varus or cubitus valgus deformity was found in all patients. At last follow-up, except that the condylar angle in group A was significantly greater than that in groups B and C ( P<0.05), there was no significant difference in other imaging indicators, elbow range of motion, or Mayo score between groups ( P>0.05). The Song type 4 of humeral lateralcondylar fracture treated with ultrasound-guided closed reduction and Kirschner wire fixation has a longer operation time, more postoperative complications, and is more prone to lateral osteophyte.

Dislocation Does Not Seem To Be an Absolute Factor Effecting the Short- to Medium-Term Poor Prognosis of Patients with Acetabular Posterior Wall Fracture.

Dislocation is a complication of acetabular fractures involving the posterior wall, but whether dislocation is an absolute factor impacting the short- to medium-term prognosis of the hip joint remains controversial. This study aimed to compare the short- to medium-term clinical and radiological results among patients diagnosed with an acetabular fracture involving the posterior wall, with or without dislocation.Seventy-nine patients diagnosed with an acetabular fracture involving the posterior wall were retrospectively divided into posterior dislocation and non-dislocation groups. All fractures were open reduction + internal fixation with a plate screw combination through the single Kocher-Langenbeck approach. The short- to medium-term radiographic outcomes of follow-up were evaluated using the Matta radiologic grading system, while the clinical outcomes were evaluated using the modified Merle d'Aubigné-Postel evaluation system.The mean follow-up duration for all patients was 43.90 (range 24-75) months. Both groups achieved similar short- to medium-term clinical and radiographic results. There seems to be no significant differences between the two groups regarding the short- to medium-term assessment of clinical and radiographic results and the occurrence of postoperative complications (p>0.05).In patients with acetabular fractures involving the posterior wall, hip dislocation is probably not an absolute determinant of a poor outcome. Even with early reduction, the short- to medium-term prognosis results appear similar to those of patients without dislocation.

Long-term results of total hip arthroplasty in severe congenital hip disease: A ten- to 20-year follow-up study

IntroductionThe impact of bone deformities, previous surgeries, and the surgical technique in total hip arthroplasty (THA) for congenital dislocation of the hip (CDH) at a long-term has not been clearly defined yet. In this single-centre observational study we sought to assess patients undergoing THA due to osteoarthritis secondary to severe CDH with low or high dislocation ten- to 20-years after surgery. To determine this purpose, we assessed: (1) THA-related complications and reoperations; (2) the clinical outcome, patients’ satisfaction and radiological results; and (3) the possible risk factors for reoperation with particular attention to the surgical technique and the influence of prior surgeries. HypothesisWe hypothesized that an anatomical reconstruction of the hip would decrease the reoperations rates in patients undergoing THA with severe CDH. MethodsSeventy-five patients (85 hips) operated between 1999 and 2012 at our large tertiary hospital were analyzed. Fifty-six hips were diagnosed as low dislocation (group 1) and 29 hips as high dislocation (group 2). The existence of prior surgeries was frequent: group 1, pelvic osteotomies 6 hips, femoral osteotomies 7, tectoplasty (shelf) 6, resection arthroplasty 1 and lowering of the greater trochanter 1; group 2 included pelvic osteotomies 10 hips, femoral osteotomies 10, and a femoral lengthening 2. The number of additional procedures during THA was: group 1 (19/56 [34%]), acetabular roof bone autograft 8 hips, acetabular medial wall autograft 2, hardware removal 6, extended femoral osteotomy 2, and a femoral shortening 1; group 2 (20/29 [69%]), acetabular bone autograft 12 hips, medial autograft 1, hardware removal 1, extended femoral osteotomy 2, and a femoral shortening 4 hips. The clinical and the radiological analysis were compared in both groups for a minimum follow-up of ten years. Cox regression models were used to detect risk factors for reoperation. ResultsNine patients (13.8%) required reoperation for the following reasons: cup loosening (5 hips), periprosthetic femoral fracture (3) and stem loosening (1); seven had prior surgeries. The 12-year survival rate for reoperation for any reason was 96.3% (95% confidence interval [CI] 91.2–100) in group 1 and 75.7% (95% CI, 65.8–90.8) in group 2 (p=0.003). Patients with high dislocation (p=0.02, hazard ratio [HR]: 6.25, 95% CI, 1.26–30.9) and those with an acetabular component inclination placed out of the target zone between 35° and 50° (p=0.03, HR: 4.27, 95% CI, 1.13–16.1) had a higher risk of reoperation. DiscussionAn optimal placement of the acetabular component decreased the reoperation rates in patients undergoing THA for severe CDH. Hips with high dislocation and the existence of prior surgery can affect THA implantation. Level of evidenceIII; retrospective; comparative.

Comparative analysis of hip arthroscopy and open surgical dislocation for treating femoroacetabular impingement

AbstractThe purpose of this study was to compare the impact of hip arthroscopy group and open surgical dislocation group as treatments for femoroacetabular impingement (FAI) in young athletes, specifically in relation to early hip osteoarthritis. A systematic search was conducted across four databases to identify controlled trials comparing hip arthroscopy and open surgical dislocation for FAI treatment. The selected studies (9 in total) underwent rigorous literature assessment and data analysis using Review Manager (RevMan) 5.3 software. The meta‐ analysis revealed that there was no statistically significant difference between hip arthroscopy group (the test group) and the open surgical dislocation group (the control group) concerning the improvement of the alpha angle (Standardized Mean Difference [SMD]: ‐5.54; 95% Confidence Interval [CI]: ‐ 12.45,1.38; p = 0.117), the Modified Harris Hip Score (mHHS) after a 12‐ month follow‐ up (SMD:0.94; 95% CI:‐ 2.87,4.75; p = 0.629) and the complication rate (OR: 0.66; 95% CI: 0.26,1.65; p = 0.372). However, the meta‐ analysis revealed that the Nonarthritic Hip Score (NAHS) after a 12‐ month follow‐ up of the test group was significantly higher than that of the control group (SMD: 6.31; 95% CI: 0.53, 12.09; p = 0.032). In terms of the reoperation rate, it demonstrated a significantly lower rate in the test group compared to the control group (OR: 0.48; 95% CI: 0.29, 0.82; p &lt; 0.01). These findings suggest that hip arthroscopy may have better outcomes for patients with FAI, as it is associated with improvements in hip function and a lower reoperation rate. However, these conclusions should be validated by further high‐ quality studies.

Insufficient stem antetorsion and lower cup abduction is a combined risk factor for posterior hip dislocation in patients undergoing THA for femoral neck fractures: a retrospective analysis

BackgroundThe role of acetabular and femoral component positions with respect to the risk of post-operative instability and dislocation remains debated. In this study, we aimed to identify potential risk factors for early dislocation following primary total hip arthroplasty (THA) for displaced intracapsular femoral neck fractures (FNF) using radiological measurements.MethodsWe retrospectively analyzed data for patients who underwent cementless primary THA for FNF using a posterolateral approach between January 2018 and December 2021. Follow-up duration, age, sex, affected side, and mean time from THA to dislocation were recorded. Leg-length inequality, abductor lever arm, vertical and horizontal femoral offsets, vertical and horizontal hip centers of rotation, abduction, anteversion of the acetabulum and femoral prosthesis, and combined anteversion were measured.ResultsThe study sample included 17 men and 34 women, with 21 and 30 patients undergoing left- and right-hip operations, respectively. The mean patient age was 70.18 ± 7.64 years, and the mean follow-up duration was 27.73 ± 13.52 months. The mean time between THA and dislocation was 1.58 ± 0.79 months. Seven patients (13.73%) sustained posterior dislocation of the hip. The abduction angle (36.05 ± 6.82° vs. 45.68 ± 8.78°) (p = 0.008) and anteversion of the femoral prosthesis (8.26 ± 4.47° vs. 19.47 ± 9.01°) (p = 0.002) were significantly lower in the dislocation group than in the control group. There were no significant differences in other parameters.ConclusionsInsufficient stem antetorsion combined with lower abduction angle of the acetabular component were associated with a high risk of dislocation, especially in patients with deep flexion or internal rotation of the flexed hip joint and knees, or in patients with a stiff spine or anterior pelvic tilt, impingement may then occur in the neck of the prosthesis and cup component, ultimately resulting in posterior dislocation. These findings could remind surgeons to avoid simultaneous occurrence of both in THA surgery. These results provide new insight into risk factors for hip dislocation in patients undergoing primary THA for FNF and may aid in reducing the risk of instability and dislocation.Level of evidenceProspective comparative study Level II.