THA in patients with acetabular bone defects is associated with a high risk of dislocation. Dual mobility (DM) cups are known to prevent and treat chronic instability. The aim of this study was to evaluate the dislocation rate and survival of jumbo DM cups. This was a retrospective, continuous, multicenter study of all the cases of jumbo DM cup implantation between 2010 and 2017 in patients with acetabular bone loss (Paprosky 2A: 46%, 2B: 32%, 2C: 15% and 3A: 6%). The indications for implantation were revisions for aseptic loosening of the cup (n=45), aseptic loosening of the femoral stem (n=3), bipolar loosening (n=11), septic loosening (n=10), periprosthetic fracture (n=5), chronic dislocation (n=4), intraprosthetic dislocation (n=2), cup impingement (n=1), primary posttraumatic arthroplasty (n=8), and acetabular dysplasia (n=4). The jumbo cups used were COPTOS TH (SERF), which combines press-fit fixation with supplemental fixation (acetabular hook, two superior flanges with one to four screws, two acetabular pegs). A bone graft was added in 74 cases (80%). The clinical assessment consisted of the Harris hip score. The primary endpoint was surgical revision for aseptic acetabular loosening or the occurrence of a dislocation episode. In all, 93 patients were reviewed at a mean follow-up of 5.3 ± 2.3 years [0, 10]. As of the last follow-up, the acetabular cup had been changed in five cases: three due to aseptic loosening (3.2%) and two due to infection (2.1%). The survivorship free of aseptic loosening was 96.8%. Three patients (3%) suffered a dislocation. At the last follow-up visit, the mean HSS scores were 72.15, (p < 0.05). Use of a jumbo DM cup in cases of acetabular bone defects leads to satisfactory medium-term results with low dislocation and loosening rates

Introduction. Orthopaedic rehabilitation of adolescences and young adults with high dislocation of the femur is rather challenging. The role of palliative salvage procedures is controversial enough in the cohort of patients. Materials and Methods. Treatment outcomes of 10 patients with congenital hip dislocation were analyzed. Mean age at intervention was 17,8 years (15–22). The grade of dislocation were assessed according to Eftekhar: type C − 2, type D − 8. The mean baseline shortening was 4.7±0.36 cm. All subjects underwent PSO with the Ilizarov method. Another osteotomy for lengthening and realignment was produced at the boundary of the upper and middle third of the femur. The mean time in the Ilizarov frame was 5.3 months. Results. The mean follow-up was 2.6±.1 years (range, 15 to 32 years). Limb shortening of 1 cm to 1. 1. /. 2. cm was observed in four cases. Functional outcomes according to d'Aubigne-Postel were: Pain 4,4±0,15 points. ROM − 4,1±0,3 points. Walking ability − 4,5±0,2 points. Two cases had good results (15–17 points), and seven patients had fair outcomes (12–14 points). A poor result (7 points) was recorded in one female patient 28 years after PSO followed by THA. Conclusions. Hip reconstruction with the Ilizarov method can be used in specific clinical situations as an alternative salvage procedure to delay THR in young patients with high dislocation of the femur

A fracture of the tuberosity is associated with 16% of anterior glenohumeral dislocations. Manipulation of these injuries in the emergency department is safe with less than 1% risk of fracture propagation. However, there is a risk of associated neurological injury, recurrent instability and displacement of the greater tuberosity fragment. The risks and outcomes of these complications have not previously been reported. The purpose of this study was to establish the incidence and outcome of complications associated with this pattern of injury. We reviewed 339 consecutive glenohumeral dislocations with associated greater tuberosity fractures from a prospective trauma database. Documentation and radiographs were studied and the incidence of neurovascular compromise, greater tuberosity fragment migration and intervention and recurrent instability recorded. The mean age was 61 years (range, 18–96) with a female preponderance (140:199 male:female). At presentation 24% (n=78) patients had a nerve injury, with axillary nerve being most common (n=43, 55%). Of those patients with nerve injuries 15 (19%) did not resolve. Greater tuberosity displacement >5mm was observed in 36% (n=123) of patients with 40 undergoing acute surgery, the remainder did not due to comorbidities or patient choice. Persistent displacement after reduction accounted for 60 cases, later displacement within 6 weeks occurred in 63 patients. Recurrent instability occurred in 4 (1%) patients. Patient reported outcomes were poor with average EQ5D being 0.73, QDASH score of 16 and Oxford Shoulder Score of 41. Anterior glenohumeral dislocation with associated greater tuberosity fracture is common with poor long term patient reported outcomes. Our results demonstrate there is a high rate of neurological deficits at presentation with the majority resolving spontaneously. Recurrent instability is rare. Late tuberosity fragment displacement occurs in 18% of patients and regular follow-up for 6 weeks is recommended to detect this

Abstract. Background. Dislocation of a hip hemiarthroplasty is a devastating complication with a high mortality rate in elderly patients. Previous studies have suggested a higher dislocation rate in patients with neuromuscular conditions. In this study, we have reviewed our larger cohort of patients to identify whether there is any association between neuromuscular disorders and prosthetic dislocation in patients treated with hip hemiarthroplasty for femoral neck fractures. Patients and Methods. Our study is a retrospective analysis of data collected over 34 years for patients with intracapsular neck of femur fracture who underwent hip hemiarthroplasty. The study population is composed of four groups: patients with no neuromuscular disorders, patients with Parkinson's disease, patients with previous stroke, and patients with dementia. Results. A total of 3827 patients were treated with hip hemiarthroplasty. For the 3371 patients with no neuromuscular condition (Group I) the dislocation rate was 1.1%. 219 patients had Parkinsonism (Group II) with a dislocation rate of 3.2%, 104 patients had a previous stroke with weakness on the fracture side with a dislocation rate of 1.0% (Group III), and 984 patients had severe dementia with a dislocation rate of 1.8% (Group IV). The increased dislocation rate for those with Parkinson's disease was statistically significant (p=0.02) while none of the other neuromuscular conditions were statistically significant. Conclusion. Our study demonstrates an increased risk of dislocation after hemiarthroplasty for patients with Parkinson's disease in comparison to other groups. No increase was apparent for those with dementia or weakness from a previous stroke

Abstract. Background. Traumatic knee dislocations are devastating injuries and there is no single best accepted treatment. Treatment needs to be customised to the patient taking into consideration injury to the knee; associated neurovascular and systemic injuries. Objective. This study looked at functional outcome of a single surgeon case series of patients who underwent surgical management of their knee dislocation. Methods. Seventy patients with knee dislocation were treated with multi-ligament reconstruction at a major trauma centre. Acute surgical repair and reconstruction with fracture fixation within 3 weeks was preferred unless the patient was too unstable (Injury severity score>16). PCL was primarily braced and reconstructed subsequently, if required. Outcome was collected prospectively using IKDC score, KOOS and Tegner score. Results. The mean age of the patients was 35yrs (17–74), 53 males and 17 females. 5 patients had CPN injury (7%), 3 had vascular injury (4.2%), 2 had combined CPN and vascular injury (2.8%). Acute surgical treatment was done in 48 patients while 10 had staged reconstruction. 22 patients had delayed reconstruction. The mean follow-up period was 4.8 years (1–12 yrs). According to the IKDC score 67% of the patients had near-normal knee function. The mean Tegner activity scale postoperatively was 4.5 (preinjury 6.5) and the mean KOOS score was 75.3. Four patients had stiffness and needed arthroscopic arthrolysis, two patients had a residual foot drop from the original injury and needed tendon transfer. Conclusion. Traumatic knee dislocation is a challenging problem but good outcomes can be achieved by surgical management

Despite recent advances in the management of slipped capital femoral epiphysis (SCFE), controversy remains about the treatment of choice for unstable slips. Surgical dislocation and open reduction has the advantage of identifying and preserving the blood supply of femoral head thereby potentially reducing the risk of avascular necrosis, (AVN). There is large variation in the literature from several small series about reported AVN rates ranging from two to 66% for unstable SCFE treated with surgical dislocation. The aim of our study was to analyze our experience with acute open reduction and internal fixation of unstable acute and unstable acute on chronic slips using the technique of surgical dislocation described by Professor Reinhold Ganz. A retrospective review of 11 patients (12 hips) treated by surgical dislocation, reduction and pinning as the primary procedure for unstable acute and unstable acute on chronic SCFE in a tertiary referral children's hospital was undertaken. This represents the entire series treated in this manner from September 2007 to January 2018. These procedures were performed by a team of Orthopaedic surgeons with significant experience performing surgical dislocation of the hip including patients with chronic SCFE, Perthes' disease, impingement and acetabular fractures. Demographic data, intraoperative records, postoperative notes and radiographs including details of subsequent surgery were reviewed. There were seven boys and four girls with mean age of 13.4 years, range 11 to 15 years at the time of surgical dislocation. Out of 12 hips, two had acute unstable slip while the remaining 10 had acute on chronic unstable slip. Six patients had good or excellent results. The remaining six patients developed AVN of which three patients had total hip replacement at six months, 17 months and 18 months following primary procedure. Seven patients required more than one operation. Three patients lost their correction and required re fixation despite surgical dislocation, reduction and fixation being their primary procedure. This series demonstrates a high percentage of AVN (50%) in severe unstable SCFE treated with surgical dislocation despite careful attention to retinacular flap development and intra operative doppler studies. This is in direct contrast to our experience with subcapital reorientation with surgical dislocation in stable slips where excellent results were achieved with a low rate of AVN. Pre-operative imaging with MRI and perfusion studies may identify where ischemia has occurred and might influence operative treatment. Based on our results, we do not recommend routine use of surgical dislocation in unstable SCFE. This technique requires further scrutiny to define the operative indications in unstable SCFE

We have previously reported on the medium-term outcomes following a non-operative protocol of a short period of splinting followed by early movement to treat simple dislocations of the elbow. We undertook extended follow up of our original patient study group to determine whether the excellent results previously reported were maintained in the very long-term. A secondary question was to determine the rate and need for any late surgical intervention. We attempted to contact all patients in the original patient study group. Patients were requested to complete the Oxford elbow score (OES), the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and a validated patient satisfaction questionnaire. Patients were requested to attend a face-to-face assessment where they underwent a clinical examination including neurovascular assessment, range-of-motion and an assessment of ligamentous stability. Seventy-one patients (65%) from the original patient study group agreed to participate in the study. The mean duration of follow-up was 19.3 years. At final follow-up patients reported excellent functional outcome scores and a preserved functional range of movement in the injured elbows. The mean DASH score was 5.22 points and the mean Oxford Elbow Score was 91.6 points. The mean satisfaction score was 90.9 points. Our study shows that the excellent outcomes following treatment with a protocol of a short period of splinting and early movement remain excellent and are maintained into the very long term. These findings support our hypothesis that this treatment protocol is appropriate and suitable for most patients with simple dislocations of the elbow. The role for primary ligamentous repair for this patient group should be carefully considered. Work to more clearly define the anticipated benefits of surgery for specific patient groups or injury patterns would help to support informed decision making

Introduction. Dislocation is a major cause of Total Hip Arthroplasty (THA) early failure and is highly influenced by surgical approach and component positioning. Robotic assisted arthroplasty has been developed to improve component positioning and therefore reduce post-operative complications. The purpose of this study was to assess dislocation rate in robotic total hip arthroplasty performed with three different surgical approaches. Methods. All patients undergoing Robotic Arm-Assisted THA at three centers between 2014 and 2019 were included for assessment. After exclusion, 1059 patients were considered; an anterior approach was performed in 323 patients (Center 2), lateral approach in 394 patients (Center 1 and Center 2) and posterior approach in 394 patients (Center 1 and Center 3). Episodes of THA dislocation at 6 months of follow up were recorded. Stem anteversion, Cup anteversion, Cup inclination and Combined Anteversion were collected with the use of the integrated navigation system. Cumulative incidence (CI), incidence rate (IR) and risk ratio (RR) were calculated with a confidence interval of 95%. Results. Three cases of dislocation (2 posterior approach, 1 anterior approach) were recorded, with a dislocation rate of 0.28% and an IR of 0.14%. Placement of cup in Lewinnek safe zone rate was 82.2% for posterior approach, 82.0% for lateral approach and 95.4% for anterior approach. Placement in the Combined Version safe zone rate was 98.0% for posterior approach, 73.0% for lateral approach and 47.1% for anterior approach. Despite the difference, dislocation IR was 0.30% for anterior approach, 0.34% for posterior approach and 0% for lateral approach. Conclusion. Robotic assisted technique is associated with low dislocation risk, especially in posterior approach. The Combined version technique appears to be a reliable way to reduce dislocation risk in the posterior lateral approach, but does not appear to be essential for lateral and anterior approaches

Background. Hip Hemiarthroplasty is one of the commonest orthopaedic operation done in UK with recent NHFD data from 2017 report showing that 43% of the 77000 patients who presented to hospital had hemiarthroplasty. Literature suggests dislocation rate of 0.8% – 6.1% for Hip Hemiarthroplasty. Dislocation of hemiarthroplasty may lead to significant morbidity and mortality. Aim. To investigate if acetabular dysplasia has a significant association with hemiarthroplasty dislocation. Methodology. Retrospective multicentre review. Review of radiographs of patients receiving a hip hemiarthroplasty for a hip fracture measuring Acetabular index (sharp angle) and Lateral Centre edge angle(CEA). A large acetabular index and lower value for the center-edge angle suggest acetabular dysplasia. Measurements were made for 20 patients with dislocation and 20 patients without dislocation. Statistical assessment of the results with unpaired t test was performed. Results. Mean acetabular angle for those with dislocation was 42.65 degrees versus 37.8 for those without dislocation giving a p value of 0.000861. Mean Center-edge angle of those with dislocation was 26.1 degrees versus 37 for those without dislocation giving a p value of 0.000019. Conclusion. This study showed that the hemiarthroplasty dislocation group had higher acetabular index and Lower Center-edge angle compared to the hemiarthroplasty group without dislocation clearly demonstrating that acetabular dysplasia is implicated in the aetiology of hip hemiarthroplasty dislocation. Hence careful review of the pre-op X-rays for dysplastic features would benefit in making a sound management plan

Introduction. Computer-assisted hip navigation offers the potential for more accurate placement of hip components, which is important in avoiding dislocation, impingement, and edge-loading. The purpose of this study was to determine if the use of computer-assisted hip navigation reduced the rate of dislocation in patients undergoing revision THA. Methods and Materials. We retrospectively reviewed 72 patients who underwent computer-navigated revision THA [Fig. 1] between January 2015 and December 2016. Demographic variables, indication for revision, type of procedure, and postoperative complications were collected for all patients. Clinical follow-up was performed at 3 months, 1 year, and 2 years. Dislocations were defined as any episode that required closed or open reduction or a revision arthroplasty. Data are presented as percentages and was analyzed using appropriate comparative statistical tests (z-tests and independent samples t- tests). Results. All 72 patients (48% female; 52% male) were included in the final analysis [Fig. 2]. Mean age of patients undergoing revision THA was 70.4 ± 11.2 years. Mean BMI was 26.4 ± 5.2 kg/m. 2. The most common indications for revision THA were instability (31%), aseptic loosening (29%), osteolysis/eccentric wear (18%), infection (11%), and miscellaneous (11%). During revision procedure, polyethylene component was most commonly changed (46%), followed by femoral head (39%), and acetabular component (15%). At 3 months, 1 year, and final follow-up, there were no dislocations among all study patients (0%). Compared to preoperative dislocation values, there was a significant reduction in the rate of dislocation with the use of computer-assisted hip navigation (31% vs. 0%; p<0.05). Discussion. Our study demonstrates a significant reduction in the rate of dislocation following revision THA with the use of computer navigation. Although the cause of postoperative dislocation is often multifactorial, the use of computer-assisted surgery may help to curtail femoral and acetabular malalignment in revision THA

Introduction. Total hip arthroplasty (THA) dislocation has been associated with different risk factors. The main difficulty in analysing dislocation is its low rate of incidence, necessitating large series for study. We assessed factors related with patients, implant characteristics, and quality of the hip reconstruction to better identify their influence on the THA dislocation rate. Material and Methods. Dislocations in 2,732 THAs performed between 2001 and 2016 were assessed with regard to factors related with the patient (gender, age, preoperative diagnosis, lumbar pathology); the implant (femoral head size, bearing surface, stem offset, femoral head/neck ratio); and the surgical technique (approach, cup and stem position, and abductor mechanism reconstruction). Regression analysis was used for different risk factors and Kaplan-Meier for survival analysis. Results. After ERAS implementation, opioid consumption decreased for hospital day one (49.5MME to 35.4MME; p=0.000) and overall hospitalization (79.5MME to 59.5MME; p=0.000). Average LOS decreased (57.84hrs to 51.87hrs; p=0.011), blood transfusion rate was unchanged (4.25% to 3.81%; p=0.725), and disposition to home over skilled nursing facility increased (80.4% to 82.5%; p= 0.022). Unplanned return-to-hospital encounters were unchanged (8.51% to 8.88%; p=0.8486). Readmission trended up during postoperative days 0–30 and trended down during postoperative days 31–90. (1.42% to 2.96%; p=0.1074) and (1.21% to 0.85%; p=0.5748), respectively. There were 92 dislocations (3.4%), of these, 62 were treated conservatively (2.3%) and 30 surgically (1.1%). Survivorship analysis for dislocation was 96.0% (95% CI:95.0–97.0) at 17 years. Among patient-related factors, greater age (p=0.001), lower activity level (p=0.001) and lumbar fusion (p<0.001) were associated with a higher dislocation rate. Among implant-related factors, a ceramic-on-ceramic THA (p<0.001) and a femoral size of 32 or 36 mm in diameter had lower dislocation rates. With regards to surgical technique, a greater acetabular abduction angle (p=0.001) and a greater distance to the hip anatomic center (p=0.006) had higher dislocation rates. A cup position outside Lewinnek´s safe zone (p<0.001) and the abductor mechanism window (p<0.001) also had a higher dislocation rate. Multivariate analysis revealed that only significant lumbar pathology (p=0.001) and lumbar fusion (p<0.001) were significant dislocation-related factors among patient-related factors. Poor reconstruction of the hip rotation (p=0.035), a cup position outside of Lewinnek's safe zone (p<0.001) and the abductor mechanism window (p<0.001) were significantly associated with a higher dislocation risk among surgical technique-associated factors. Conclusions. Significant lumbar spine pathology increases the rate of dislocation. A proper reconstruction of the hip, including appropriate cup position and rotation centre reconstruction of the hip are essential to decrease the risk of dislocation after primary THA. The weakness of the abductor muscles is also an important cause for dislocation

Background. Inpatient dislocation after total hip arthroplasty (THA) is considered a non-reimbursable “never event” by the Centers for Medicare and Medicaid Services. There is extensive evidence that technical procedural factors affect dislocation risk, but less is known about the influence of non-technical factors. We evaluated inpatient dislocation trends following elective primary THA, and identified patient and hospital characteristics associated with the occurrence of dislocation. Methods. We used discharge records from the Nationwide Inpatient Sample (2002–2011). Temporal trends were assessed and multivariable logistic regression modeling was used to identify factors associated with dislocation. Results. The in-hospital dislocation rate increased from 0.025% in 2002 to 0.15% in 2011, despite a downward trend in length of stay (P<0.001). Patient characteristics associated with the occurrence of dislocation were black or Hispanic race/ethnicity, lower household income, and Medicaid insurance. Comorbidities associated with dislocation included hemiparesis/hemiplegia, drug use disorder, chronic renal failure, psychosis, and obesity. Dislocations were less likely to occur at teaching hospitals and in the South. Conclusion. The in-hospital dislocation rate following elective primary THA is increasing, in spite of shorter stays and surgical advances over time. Given the sociodemographic disparities in dislocation risk documented herein, interventions to address social determinants of health might do as much or more to reduce the occurrence of dislocation than technical improvements

Introduction. After aseptic loosening, dislocation of hip prosthesis is the most frequent complication in patients with hip arthroplasty, with annual cost of treatment from 70 to 100 million dollar (American estimation). Materials and methods. In the periods between January 2000 and December 2005, 359 hip arthroplasty surgeries were done in orthopedic clinic of Torretti Hospital of Ancona – Italy as following: 279 cases of primary hip arthroplasty and 80 cases of revision hip prosthesis with rate of dislocation: Total number of cases are 24 from 359 (6.6%) cases as following: 15 cases (5,3%) after primary hip arthroplasty and with rate of dislocation 9 cases (11,2%) after revision hip arthroplasty, all the dislocated case are followed retrospectively as following:. -. We analyzed our data according to the followings. -. Primary pathologies in the dislocated hip cases. -. Models of prosthesis that have been implanted (ABG II, Doufit SAMO, Ancafit Cremascoli). -. Causes of dislocation and time of dislocation regarding the date of operation. -. Types of treatment used in dislocated cases. Conclusion. Concerning to the perioperative complications and risk of factors, our data are accepted to those with similar criteria mentioned in literature. Some factors (as example, good patient selection, good preoperative planning, good experience of the surgeon and regular clinical and radiographic follow up) can favor good results with less complications. The surgical treatment becomes indispensable after second episode of dislocation, especially if the hip is highly unstable after the closed reduction. The corrected therapeutic choice depends on the determining cause of the dislocation (imbalance of the soft tissues, malposition of the prosthetic components or both) 3. -. Modularity of DOUFIT SAMO Prosthesis is considered as indispensable factor because it is nearly accommodate the anatomy of Hip joint and so can decrease the possibility of hip prosthesis dislocation after both primary and revision hip arthroplasty. This study emphasizes the need for further researches on the geometry of the hip prosthesis that may lead to decrease the risk of dislocation after hip arthroplasty

The objective of this study was to determine whether the bearing surface is a risk factor for revision after late dislocation in total hip arthroplasty (THA). Data from primary THAs were extracted from the New Zealand Joint Registry over a 13-year period. The mean age of patients was 68.9 years; 53.2% were female. The surgical approach used was posterior in 66% of THAs, lateral in 29% and anterior in 5%. There were 53,331 (65.1%) metal-on-polyethylene THAs, 14,093 (17.2%) ceramic-on-polyethylene, 8,177 (10.0%) ceramic-on-ceramic, 461 (0.5%) ceramic-on-metal, 5910, and (7.2%) metal-on-metal. The primary endpoint was late revision for dislocation, with ‘late’ defined as greater than one year post-operatively. 73,386 hips were available for analysis. The overall revision rate was 4.3% (3,130 THAs), 1.1% (836) were revised for dislocation. Only 0.65% (470) hips were revised for dislocation after the first post-operative year. The unadjusted hazard ratios (HR) showed significantly higher rates of revision for dislocation in ceramic-on-polyethylene (HR 2.48; p=0.001) and metal-on-polyethylene (HR 2.00; 95% p =0.007) compared to ceramic-on-ceramic. However, when adjusted for head size, age and surgical approach, only ceramic-on-polyethylene (HR 2.10; p=0.021) maintained a significantly higher rate of revision, whereas metal-on-polyethylene approached significance (HR 1.76; 95% p = 0.075). In New Zealand, dislocation is the most common reason for revision, ahead of aseptic loosening of the acetabular component. The relationships between bearing materials and risk of revision for late dislocation is controversial. However, in this study ceramic-on-ceramic shows lower risk rates for revision than other bearing surface combinations. Low wear and less debris, limited peri-articular inflammatory reaction and an healthy fibrotic pseudo-capsule are potential factors determining long-term stability of the hip joint

We report a rare case of Hip Resurfacing dislocation three years after a bilateral Hip Resurfacing in a very strong patient and show the maneuver to do a closed reduction on a film done at the surgical theatre under general anesthesia. Hip resurfacing dislocation is a very rare entity described in the literature and more rare after three years. With conventional total hip replacement the dislocation rate is 2–5%. In the international literature the dislocation rate with resurfacing is 0.21%. We describe a case of a 47 years old male patient who was submitted to a biltateral 54 × 60 mm Hip Resurfacing in November 16 th and 18th, 2011 (two separate days). He had a normal post op and returned to his work after six weeks and recreational activities after four months. Three years later, on November 8th, 2014 he did an extreme movement of hip flexion, adduction and internal rotation when he was gardening and planting a tree seedling suffering a left hip dislocation. Hopefully we could reduce the dislocated hip in a closed manner in the following morning. Patient went home next day but on that same night had important abominal pain needing to return to hospital when numerous gallbladder stones where found being submitted to a total laparoscopic colecistectomy two days later. It was really a bad luck week. Metal ions are still normal and patient is symptomless until today having returned to his recreational activities. We will show in a movie the maneuver to do this closed reduction and hope by showing this maneuver that our colleagues do not have to do an open dislocation in the future in case they face a Hip Resurfacing dislocation

Surgical treatment options for Femoroacetabular impingement (FAI) includes both surgical dislocation and hip arthroscopy techniques. The primary aim of this study was to evaluate and compare the survivorship of arthroscopies (scope) and surgical dislocations (SD) at minimum 5-year follow-up. The secondary aim was to describe differences in functional outcomes between the 2 groups. This was a retrospective, single surgeon, consecutive, case-series from a large tertiary care centre. We evaluated all surgeries that were performed between 2005 and 2011. Our institutional database was queried for any patient undergoing surgery for FAI (pincer (n=23), cam (n=306), or mixed (n=103) types). Patients with childhood pathologies i.e. Legg Calve Perthes and slipped capital femoral epiphysis were excluded. This resulted in 221 hips (169 males, 52 females) who underwent either SD (94, 42.5%) or scope (127, 57.5%). A manual chart review was completed to identify patients who sustained a complication, underwent revision surgery or progressed to a total hip arthroplasty (THA). In addition, we reviewed prospectively collected patient reported outcome measure (PROMs) using (SF12, HOOS, and UCLA). Survivorship outcome was described for the whole cohort and compared between the 2 surgical groups. PROMs between groups were compared using The Mann-Whitney U test and the survival between groups was assessed using the Kaplan-Meier Analysis and the Log-Rank Mantel Cox test. All analyses were performed in SPSS (IBM, v. 26.0). The cohort included 110 SDs and 320 arthroscopies. The mean age of the whole cohort was 34±10; patients in the SD group (32±9) were younger compared to the arthroscopy group (39±10) (p<0.0001). There were 16 post-operative complications (similar between groups) and 77 re-operations (more common in the SD group (n=49) due to symptomatic metal work (n=34)). The overall 10-year survival was 91±3%. Survivorship was superior in the arthroscopy group at both 5- (96% (95%CI: 93 – 100)) and 8- years 94% (95%CI: 90 – 99%) compared to the SD Group (5-yr: 90% (95%CI: 83 – 98); 8-yr: 84% (95%CI:75 – 93)) (p=0.003) (Figure 1). On average HOOS improved from 54±19 to 68±22 and WOMAC from 65±22 to 75±22. The improvement in PROMs were similar between the 2 groups. We report very good long-term joint preservation for the treatment of FAI, which is similar to those reported in hip dysplasia. In addition, we report satisfactory improvement in function following such treatment. The differences reported in joint survival likely reflect selection biases from the treating surgeon; more complex cases and those associated with more complex anatomy were more likely to have been offered a SD in order to address the pathology with greater ease and hence the inferior joint preservation identified in this group. For any figures or tables, please contact the authors directly

Introduction. Dislocation is one of severe complications after total hip arthroplasty (THA). Direct anterior approach (DAA) is useful for muscle preservation. Therefore, it might be also effective to reduce dislocation. The purpose of this study is to investigate the ratio and factors of dislocations after THA with DAA. Materials & methods. Nine hundred fifity two primary THAs with DAA are examined. Mean age at operation was 64.9 yrs. 838 joints are in women and 114 (joints) in men. All THAs were performed under general anesthesia in supine position. We reviewed the ratio, onset and frequency of dislocations, build of the patients, preoperative Japanese Orthopaedic Association (JOA) Hip scores, implant setting angles, pelvic tilt angles and diameter of inner heads. Results. The ratio of dislocation was 14 joints (1.47%). All patients were women and mean age was 67.1 yrs. Anterior dislocation was in 9 joints and posterior was in 5 joints. Primary diagnosis for THA was the following: osteoarthritis in 9 hips and rheumatoid arthritis in 5 (hips). About primary onset, 7 joints were within 3 weeks, 5 joints from 3 weeks to 3 months and 2 joints after 3 months. About frequency, 9 joins were simple and 5 joints were multiple. Revision surgery was done in 2 joints due to ceramic fracture and cup migration. About build of the patients, mean body height was 153.1cm, mean body weight (was) 55.6 kg and mean BMI (was) 23.6. Mean preoperative JOA score was 40.0 points. Implant setting angles were the following: mean cup inclination was 42.4 degree, mean cup anteversion (was) 24.8 degree and mean stem anteversion (was) 18.7 degree. Cup inclination and anteversion in the anterior dislocation group were bigger than that in no dislocation group. Stem anteversion in the posterior dislocation group was smaller than that in no dislocation group. The difference of pelvic tilt angle between supine and standing position was 6.4 degree. It was significant bigger in the posterior dislocation group. The most of used Inner head was 28mm in 375 joints. There was no significant difference of the dislocation rate among inner head size. Discussion and conclusion. DAA-THA can expect the reduction of dislocation rate due to intermusclar approach; however there are some reports of high dislocation rate because of difficult technique. In our study, dislocation ratio was 1.47%. Risk factors of dislocation after THA was rheumatoid arthritis, large cup inclination and anteversion for anterior dislocation, small stem anteversion and large difference of pelvic tilt angle between supine and standing position for posterior dislocation

Background. Dislocation is one of the commonest complications of total hip arthroplasty (THA) with incidence of between 0.3 and 10% in primary, and from 15 % to 30% of revision cases. Despite this, little is known of the outcome of treatment strategies for dislocation. In this study, we evaluated clinical results in patient undergoing revision THA for recurrent dislocation. Materials and Methods. Twenty-four hips underwent revision THA for recurrent instability between 1998 and 2011 at our institution. Nine patients were male, and 15 were female. At the time of revision, the average age was 69.9 years (range, 45–83 years). Average follow-up was 29.8 months (range, 6–72 months). We recorded the number of times of dislocation, the direction of dislocation, the factor of dislocation and the operative strategy employed for each case. Demographic data and surgical treatment used were analyzed to determine risk factors for failure. We performed Mann-Whitney rank sum test, Student's t-test and Fisher exact test to evaluate the factors influencing failure. Significance was defined as a p value of <0.05 (Statistical Package for Social Sciences (SPSS) version 12.0 J for Windows (SPSS Inc., Chicago, IL, USA)). Results. Before revision surgery, dislocation was occurred more than three times in all cases. The anterior dislocation was only four cases. In the factor of dislocation, 5 were malposition of implant, 11 were soft tissue imbalance, 3 were highly posterior tilting of pelvic and 5 were multi-factorial. Revision treatment includedã��liner and ball exchange in 19 hips, cup exchange in 5 hips. There was eight substitution to constrain liner for sever soft tissue imbalance. Nine (37.5%) had further dislocation. Cup revision for implant malposition was a successful method in recurrent instability (P=0.04). Constrain liner exchange (P=0.03) was associated with higher failure rate. Conclusion. Recurrent dislocation has complex problems with multifaceted etiology that requires extensive preoperative planning of each dislocation factors and availability of multiple surgical options

Objective. By retrospective analysis of clinical data, to find new risk factors for postoperative dislocation after total hip replacement and the dose-effect relationship when multiple factors work simultaneously. Methods. A nested case-control study was used to collect the dislocated hips from 5513 primary hip replacement case from 2000 to 2012. Apart from the patients with given cause of dislocation, 39 dislocated hips from 38 cases were compared with 78 hip from 78 cases free from dislocation postoperatively, which matched by the admission time. The factors that may affect the prosthetic unstable was found by the univariate analysis, and then they were performed multivariate logistic regression analysis and evaluation of a dose-effect factors. Results. The clinical scores between the two groups was no significant difference before and after surgery. Univariate analysis revealed the position of acetabular prosthesis (P = 0.05) and the big ball (P=0.01) differences were statistically significant. While patient with adduction deformity incorporating limb lengthening≧2cm(P<0.01) or the knee valgus deformity incorporating pelvic obliquity (P=0.01), as well as bilateral cases (P=0.02) were also the risk factors for dislocation. Big head decrease the dislocation rate. Multivariate analysis confirmed these newly founded factors are more important than the classic factors in this group of patients. Conclusion. Patients with hip adduction deformity combined with limb lengthening, knee valgus deformity combined with pelvic obliquity and bilateral pathological hip seem more predisposed to dislocation after total hip arthroplasty, who should be strengthened preoperative education and postoperative management to prevent. Key Word. total hip arthroplasty, dislocation, multivariate analysis

Introduction. Computer navigation systems are quite sophisticated intra-operative support systems for the precise placement of acetabular or femoral components in THA. However, few studies have addressed the clinical benefits derived from using a navigation system to achieve precise placement of the implants. The purpose of this study is to investigate the early dislocation rate of navigation-assisted primary THA through a posterior approach in order to clarify the short-term benefit of using a computer navigation system. Methods. We retrospectively reviewed the early dislocation rate (within 12 months after surgery) of 475 consecutive primary cementless or hybrid THAs with femoral head sizes ≦32mm performed via posterior approach. There were 85 men and 390 women, with a mean age of 60 years (17 to 88) at operation. Preoperative diagnoses included osteoarthritis in 384 hips, osteonecrosis in 45 hips, and others in 46 hips (ex. RA, trauma, infection, congenital disease). All THAs were planned using a 3D templating system based on the combined anteversion theory, performed by single surgeon through a posterior approach with repair of the posterior capsule, assisted by a CT-based surface matching type computer navigation system for cup implantation. All patients were directly followed up at least 1 year after surgery. We classified all 475 joints into four groups: normal or mildly deformed hips (Group A; 308 joints, ex. primary OA, Crowe group 1, osteonecrosis), moderately deformed hips (Group B; 97 joints, ex. Crowe group 2, protrusio acetabuli, Perthes like deformity), severely deformed hips (Group C; 53 joints, ex. Crowe group 3 or 4, ankylosis, fused hip), and neuromuscular and cognitive disorders (Group D; 17 joints), and examined the dislocation rate for each group. Results. We had eleven early dislocations, for an overall dislocation rate of 2.3% (11/475). All dislocations occurred posteriorly within 6 weeks after surgery. Three joints were Crowe group 4 dislocated hips, three were Charcot joints, two were Girdlestone hips after pyogenic arthritis, two was a Crowe group 1 hip, and one was osteonecrosis. All 11 cups were implanted within 5 degree of error from the preoperative planning, and all were placed within the Lewinnek safe zone. The dislocation rates according to group were 0.6% for group A (2/308), 0% for B (0/97), 9.4% for C (5/53), and 23.5% for D (4/17). Discussion. The use of computer navigation system in patients undergoing THA improves the precision of acetabular cup placement by decreasing the number of outliers, which may result in reducing the risk of dislocation. In this series, most dislocations occurred in the highly risky or rare condition cases in groups C or D. In such cases, precise and appropriate cup implantation assisted by the navigation system could not completely prevent dislocation because of the patients' specific special backgrounds. On the other hand, early dislocation was prevented for the normal/mild to moderately deformed joints such as those in groups A or B. Computer navigation system was effective for prevent early dislocation in the normal or mild to moderately deformed joints