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

Adverse spinopelvic characteristics (ASC) have been associated with increased dislocation risk following primary total hip arthroplasty (THA). A stiff lumbar spine, a large posterior standing tilt when standing and severe sagittal spinal deformity have been identified as key risk factors for instability. It has been reported that the rate of dislocation in patients with such ASC may be increased and some authors have recommended the use of dual mobility bearings or robotics to reduce instability to within acceptable rates (<2%). The aims of the prospective study were to 1: Describe the true incidence of ASC in patients presenting for a THA 2. Assess whether such characteristics are associated with greater symptoms pre-THA due to the concomitant dual pathology of hip and spine and 3. Describe the early term dislocation rate with the use of ≤36mm bearings. This is an IRB-approved, two-center, multi-surgeon, prospective, consecutive, cohort study of 220 patients undergoing THA through anterolateral- (n=103; 46.8%), direct anterior- (n=104; 27.3%) or posterior- approaches (n=13; 5.9%). The mean age was 63.8±12.0 years (range: 27.7-89.0 years) and the mean BMI 28.0±5.0 kg/m. 2. (range: 19.4-44.4 kg/m. 2. ). There were 44 males (47.8%) and 48 females (52.2%). The mean follow-up was 1.6±0.5 years. Overall, 54% of femoral heads was 32 mm, and 46% was 36mm. All participants underwent lateral spinopelvic radiographs in the standing and deep-flexed seated positions were taken to determine lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic-femoral angle (PFA) and pelvic incidence (PI) in both positions. Spinal stiffness was defined as lumbar flexion <20° when transitioning between the standing and deep-seated position; adverse standing PT was defined as >19° and adverse sagittal lumbar balance was defined as mismatch between standing PI and LL >10°. Pre-operative patient reported outcomes was measured using the Oxford Hip Score (OHS) and EuroQol Five-Dimension questionnaire (EQ-5D). Dislocation rates were prospectively recorded. Non-parametric tests were used, significance was set at p<0.05. The prevalence of PI-LL mismatch was 22.1% (43/195) and 30.4% had increased standing PT (59/194). The prevalence of lumbar stiffness was 3.5% (5/142) and these patients had all three adverse spinopelvic characteristics (5/142; 3.5%). There was no significant difference in the pre-operative OHS between patients with (20.7±7.6) and patients without adverse spinopelvic characteristics (21.6±8.7; p=0.721), nor was there for pre-operative EQ5D (0.651±0.081 vs. 0.563±0.190; p=0.295). Two patients sustained a dislocation (0.9%): One in the lateral (no ASC) and one in the posterior approaches, who also exhibited ASC pre-operatively. Sagittal lumbar imbalance, increased standing spinal tilt and spinal stiffness are not uncommon among patients undergoing THA. The presence of such characteristics is not associated with inferior pre-operative PROMs. However, when all characteristics are present, the risk of instability is increased. Patients with ASC treated with posterior approach THA may benefit from the use of advanced technology due to a high risk of dislocation. The use of such technology with the anterior or lateral approach to improve instability is to date unjustified as the rate of instability is low even amongst patients with ASCs

BACKGROUND. Early dislocation is a foremost complication of total hip arthroplasty through a postero-lateral approach. The extra-articular impingement of the anterior part of the great trochanter with ileum bone, with or without soft tissue interposition is a well recognized but underestimated etiopathogenetic cause reported in literature. In this retrospective study through the assessment of clinical and radiographic follow-up at a minimum of six months, the effectiveness of an antero- longitudinal osteotomy of the great trochanter for early dislocation prevention is evaluated. MATERIALS AND METHODS. 209 patients (48.3% males and 51,7% females) underwent a total hip arthroplasty from June 2011 to September 2015, with surgery being performed by the same surgeon. A modified posterolateral approach was used according to the tissue-sparing criteria, in all the cases an anterior longitudinal osteotomy of the great trochanter has been performed at 90° to the antiversion angle of the implant and aligned posteriorly with the prosthesis. All the patients underwent a clinical and radiological follow up at one, three, and six months. RESULTS. In this study, only one patient reported dislocation of THA. One patient suffered from a wound infection which was subsequently treated with antibiotics and had complete remission. All patients demonstrated a fast recovery of ROM and walking, starting from pre-op Harris Hip Score 42.24pts and obtaining a score of 81.52pts at three months, and 92.03 at six months post-op. After surgery and during the follow up period, there were no trochanteric fractures detected. DISCUSSION. The correct positioning of the implants, the head diameter, offset, soft tissues repair, absence of impingement, and patients compliance are all elements that define the prosthetic stability. Literature shows and incidence of primary total hip arthroplasty dislocation between 0.80% to 10%. The incidence of dislocation reported in a preliminary study in our Institute is 0.48%, demonstrating the effectiveness of the trochanteric osteotomy. CONCLUSIONS. The osteotomy of the great trochanter is an effective surgical technique used to decrease the anterior impingement and early dislocation incidence. It is particularly effective on patients with good compliance and correctly implanted prosthetic components

Surgeons often target the Lewinnek zone (40°±10° of inclination; 15°±10° of anteversion) for acetabular orientation during total hip arthroplasty (THA). However, matching native anteversion (20°-25°) may achieve optimal stability. The purpose of this study was to (1) determine incidence of early dislocation with increased target acetabular anteversion, and (2) report the accuracy of imageless navigation for achieving target acetabular position in a large, single-surgeon cohort. A posterolateral approach with soft tissue repair was performed in the 553 THA meeting the inclusion criteria. The same imageless navigation system was used for acetabular component placement in all THA. Target acetabular orientation was 40° ± 10° of inclination and 25° ± 10° of anteversion. Computer software was used to measure acetabular positioning on 6-week postoperative anteroposterior pelvic radiographs. Incidence of dislocation within 6 months of surgery was determined. Repeated measures multiple regression using the Generalised Estimating Equations approach was used to identify baseline patient characteristics (age, gender, BMI, primary diagnosis, and laterality) associated with component positioning outside of the targeted ranges for inclination and anteversion. Fisher exact tests were used to examine the relationship between dislocation and component placement in either the Lewinnek safe zone or the targeted zone. All tests were two-sided with a significance level of 0.05. Mean inclination was 42.2° ± 4.9°, and mean anteversion was 23.9° ± 6.5°. 82.3% of cups were placed within the target zone. Variation in anteversion accounted for 67.3% of outliers. Only body mass index was associated with inclination outside the target range (p = 0.017), and only female gender was associated with anteversion outside the target range (p = 0.030). Six THA (1.1%) experienced early dislocation, and 3 THA (0.54%) were revised for multiple dislocations. There was no relationship between dislocation and component placement in either the Lewinnek zone (p = 0.224) or the target zone (p = 0.287). This study demonstrates that increasing target acetabular anteversion using the posterolateral approach does not increase the incidence of early THA dislocation. However, the long-term effects on bearing surface wear and stability must be elucidated. The occurrence of instability even in patients within our target zone emphasises the importance of developing patient-specific targets for THA component alignment

Component malposition in total hip arthroplasty (THA) contributes to wear, dislocation, and leg length discrepancy (LLD). Robotic assisted total hip arthroplasty (rTHA) utilises computer-assisted haptically guided bone preparation and implant insertion to improve accuracy. The goal of this study is to compare accuracy and clinical outcome with manual THA (mTHA) and rTHA at minimum 1 year follow-up interval. Consecutive primary THA performed by one fellowship trained surgeon included: the first 100 mTHAs in his clinical practice (Group1- year 2000), the last 100 mTHAs before rTHA use (Group2- year 2010), and the first 100 rTHA (Group3- year 2011). All THAs utilised cementless implants, cross-linked polyethylene, and a posterior approach. Comparisons included age, sex, diagnosis, implant head size, blood loss (EBL), operative time, LLD, early dislocation and infection. Acetabular abduction (AAB), anteversion (AAV), and LLD were measured using validated software (Martell Hip Analysis Suite). The Lewinnek safe zone defined accuracy (AAB- 30°-50°, AAV- 5°-25°). Statistical analysis included ANOVA, Chi squared, and Fisher tests. Power analysis demonstrated adequate sample sizes. No differences were noted regarding group demographics. Average operative times varied: Group 1, 2, and 3- (160, 129, and 143 minutes, respectively). No deep infections occurred in any group. LLD greater than 1.5 cm varied: Groups 1, 2, and 3 (9%, 1%, 1%, respectively). Dislocation rates varied: Groups 1, 2, and 3- (5%, 3%, and 0%, respectively). EBL was less with rTHA than mTHA (Groups 1, 2, 3: 533cc, 437cc, 357cc, respectively). Average implant head size increased comparing Groups 1, 2, and 3 (31mm, 34.6mm, and 35.2mm, respectively). AAB accuracy varied: Groups 1, 2, and 3 (66%, 91%, and 98%, respectively). AAB greater than 55 degrees varied: Groups 1, 2, and 3 (15%, 1%, and 0%, respectively). There was a 3% fractured acetabular liner rate in Group 1, all cases occurred with AAB > 55 degrees, and AAB greater than 55 degrees correlated with increased acetabular liner fracture rate (20% vs. 0%, P < 0.05). No cases of fractured acetabular liners occurred in Group 2 or 3. rTHA improved AAV accuracy compared with mTHA (Group 2- 48%, Group 3- 75%; p<0.0001). Improved acetabular component accuracy with rTHA correlated with lower dislocation rates compared with mTHA (p<0.001). Total hip arthroplasty performed with traditional manual techniques has demonstrated excellent clinical outcomes in the majority of patients with many THA designs if components are placed accurately. Limitations in mTHA remain that alter results if accurate component placement is not achieved. In our study, clinical experience over 10 years improved AAB accuracy with mTHA, but AAV remained problematic. rTHA improved AAB and AAV accuracy compared with mTHA and demonstrated reduced early dislocation rates, improved rate of LLD, and reduced acetabular liner fracture risk compared with mTHA (p<0.05). Average rTHA operative times were 14 minutes longer than mTHA (Group 2), but this was not associated with increased EBL or infection rates. Further study is needed to evaluate whether the short term clinical and radiographic advantages noted with rTHA compared with mTHA will be maintained at longer follow up intervals

The current, most popular recommendation for cup orientation, namely the Lewinnek box, dates back to the 70's, that is to say at the stone age of hip arthroplasty. Although Lewinnek's recommendations have been associated with a reduction of dislocation, some complications, either impingement or edge loading related, have not been eliminated. Early dislocations are becoming very rare and most of them probably occur in “outlier” patients with atypical pelvic/hip kinematics. Because singular problems usually need singular treatments, those patients need a more specific personalised planning of the treatment rather than a basic systematic application of Lewinnek recommendations. We aim in this review to define the potential impacts that the spine-hip relations (SHRs) have on hip arthroplasty. We highlight how recent improvements in hip implants technology and knowledge about SHRs can substantially modify the planning of a THR, and make the «Lewinnek recommendations» not relevant anymore. We propose a new classification of the SHRs with specific treatment recommendations for hip arthroplasty whose goal is to help at establishing a personalized planning of a THR. This new classification (figures 1 and 2) gives a rationale to optimize the short and long-term patient's outcomes by improving stability and reducing edge loading. We believe this new concept could be beneficial for clinical and research purposes

INTRODUCTION. The direct anterior approach to THR has become an increasingly popular minimally-invasive technique in an effort to minimize dislocation risk, facility early recovery, and diminish soft tissue injury. However, it has been associated with unique complications including intraoperative femur fracture, cutaneous nerve palsy, stem subsidence, and wound healing complications. These risk of these complications have been documented to be more likely in the surgeon's early experience with the approach. The minimally-invasive Supercapsular Percutaneous-Assisted (SuperPATH) technique was developed to minimize capsular and short-external rotator injury, minimize dislocation risk, and provide an easier transition from the standard posterior approach. METHODS. Fifty (50) consecutive elective total hip replacements in 48 patients were performed using the SuperPATH technique. These also represented the first fifty elective THRs the surgeon performed in practice. Indications were primary or secondary osteoarthritis (92%), avascular necrosis (6%), and impending pathologic fracture (2%). Patients were evaluated retrospectively for dislocation, major, and minor complications. RESULTS. At average follow-up of 10.9 months (Range 1–27 months), there were no dislocation events. There was one periprosthetic fracture identified at 14-day follow-up that required femoral revision surgery in an elderly female patient with osteoporosis. Otherwise, there were no reoperations for any reason. There were no wound complications or deep infections. There was one stem subsidence (2%) of 4 mm. There were no neurovascular injuries. CONCLUSION. The SuperPATH technique can likely be performed at an early experience level with low early complication risk and lower early dislocation risk. This minimally-invasive technique deserves further interest and evaluation as it may present a gentle learning-curve to surgeons

The main causes of total hip arthroplasty (THA) revisions are loosening and instability. Use of a dual mobility cup cemented in a acetabular reconstruction cage device limits the risk of instability and does not hinder the acetabular fixation during THA revisions. The objective of this study was to analyse a retrospective series of 123 THA revisions with antiprotusio cage and dual mobility socket. Patients and methods: At a mean follow-up of 10 years, we analysed a continuous series of 123 revisions using a reconstruction device (87 Kerboull cross-plates, 12 Burch-Schneider antiprotrusio cages, 24 custom-fit Novae ARM cages associated in all cases with a Novae Stick dual mobility cup cemented into the cage). There were 80 women and 43 males. The mean age at the surgery was 69.2 years old. PMA score increased from 9.6 +/− 3.06 preoperatively to 14.2 +/− 2. at the follow-up. 9 early dislocations occurred and one late dislocation. At the last follow-up, the X-rays showed nine hardware failures, including one cross-plate fracture, one hook fracture, and one flange fracture. Analysis of the radiological position of the cup showed a mean lowering of 13 mm and a 7 mm lateralisation compared to the preoperative position. 2 revisions for aseptic loosening and 3 for septic loosening were performed. This study confirms the advantage of dual mobility cups during acetabular reconstruction cemented in antiprotrusio cages as a way to limit, without eliminating, the risk of dislocation. Therefore cemented fixation of dual mobility cups in cages appears to be a reliable short-term option

BACKGROUND. Ideal treatment of displaced femoral neck fragility fractures in the previously ambulatory patient remains controversial. Treating these patients with total hip arthroplasty has improved patient reported outcomes and reduced rates of revision surgery compared to those treated with hemiarthroplasty. However, possible increased risk of dislocation remains a concern with total hip arthroplasty. The anterolateral and direct anterior approaches to total hip replacement have been applied in the femoral neck fracture population to minimize dislocation rates. However, the anterolateral approach has been associated with abductor injury and increased rates of heterotopic ossification while the anterior approach has been associated with peri-prosthetic femur fracture, lateral femoral cutaneous nerve injury, and wound complications. The Supercapsular Percutaneously Assisted (SuperPATH) approach was developed to minimize disruption of the capsule and short-external rotators in an effort to reduce the risk of dislocation and assist in quicker recovery in the elective hip arthroplasty setting. To achieve this, the SuperPATH technique allows the femur to be prepared in situ and the acetabulum to be reamed percutaneously once the femoral head is removed. This study investigates the post-operative time to ambulation, length of stay, discharge destination, and early dislocation rate of previously ambulatory patients with a displaced femoral neck fragility fracture that were treated with a total hip arthroplasty via the SuperPATH technique. METHODS. A retrospective chart review was performed of previously ambulatory patients consecutively treated for a displaced femoral neck fragility fracture with a total hip replacement using the SuperPATH technique. Thirty-five patients were included in the study and examined for demographic data, time to ambulation, length of stay, major and minor complications during their hospital stay. Phone interviews were conducted to check for dislocation events. RESULTS. Thirty-five patients were included in the study with an average age of 75.7 years old (range 51–95). Patients spent an average of 5.35 ± 1.61 days in the hospital and were discharged on post-operative day 3.6 ±1.38. 89% of patients were able to stand and ambulate by post-operative day 1, and 97% of patients were able to stand and ambulate before discharge from the hospital. 26% of patients were able to be discharged home, 46% were discharged to in-patient rehabilitation, 23% were discharged to a skilled nursing facility, and one patient was discharged to hospice. There were no iatrogenic femoral fractures caused, no incidents of symptomatic heterotopic bone formation, and no superficial or deep wound infections. 88.5% of patients had adequate follow up averaging 370.6 ±235.18 days, with no dislocation events observed. CONCLUSION. These early results indicate that minimally invasive total hip arthroplasty utilizing the SuperPATH technique is a safe and effective treatment for displaced femoral neck fragility fractures in the previously ambulatory patient. Additionally, this technique allows for early ambulation without an increased risk of dislocation

Introduction. Dislocation due to suboptimal cup positioning is a devastating complication in the early phase after total hip arthroplasty. Malpositioning can also result in other mechanical complications like subluxation, edge loading, increased debris, surface damage or squeaking in ceramic-on-ceramic hips. Preventing at least some of these complications in younger and more active patients is of paramount interest for the individual patient and for the society since optimized component orientation is an important determinant to reduce such risks and to further increase longevity of the implant. This study reports on two new surgical instruments that help the orthopedic surgeon to manually place both components within the optimized combined safe-zone (cSafe-Zone). Material and Methods. More than 900 minimal-invasive total hip arthroplasties (MIS-THA) have been performed between 2007 and 2015 in our institution using the minimal-invasive direct anterior approach (DAA) on an orthopedic table with foot holder. Cups were implanted applying the “stem-first” surgical technique i.e. the prosthetic stem dictates the orientation of the socket depending on the prosthesis design. A system-specific trial head which indicates the prosthesis-specific relative orientation of cup and stem and a modified cup impactor were used to finally seat the definitive acetabular socket manually during trial stem reduction while fully visually controlling the optimal orientation of the cup during impaction. This surgical technique drives both components into their optimal relative positions according to the combined version and the combined safe-zone concept in total hip arthroplasty. Results. Both new instruments, femoral trial head as well as the modified cup impactor, provide an easy way to manually control the optimal placement of the acetabular socket during impaction intraoperatively. The combined safe-zone is clearly indicated and the inverse interrelationship of stem and cup anteversion is ideally reflected by this simple mechanical system. In patients operated on with the “stem-first” technique the components were placed in the new cSafe-Zone in 94% of the cases and no squeaking or prosthetic impingement did occur in any of these patients. One early dislocation did occur and was treated by closed reduction. Conclusion. Stem-first technique using trial head-controlled impaction with a modified cup impactor is ideally suited for the minimal-invasive direct anterior approach in total hip arthroplasty to control the placement of both prosthetic components. It assists the surgeon in aligning the cup and the stem according to the cSafe-Zone in order to get the intended range of movement (iROM)

Dual mobility components for total hip arthroplasty provide for an additional articular surface, with the goals of improving range of motion, jump distance, and overall stability of the prosthetic hip joint. A large polyethylene head articulates with a polished metal acetabular component, and an additional smaller metal head is snap-fit into the large polyethylene. New components have been released for use in North America over the past four years. In some European centers, these components are routinely used for primary total hip arthroplasty. Some surgeons in USA suggest routine use in primary hip arthroplasty. However, their greatest utility is to manage recurrent dislocation in the setting of revision total hip arthroplasty. Recent biomechanical data suggests that, in a 3D CT scan-cadaver hip model, there is no difference in range of motion between a 36mm head and an ADM dual mobility component sizes 50–56mm. There is little wear data on dual mobility components, except from one implant manufacturer. It is feared that there is a “3rd articulation” in dual mobility components—the routine impingement of the femoral neck against the polyethylene femoral head. Several retrospective series have shown satisfactory results for these dual mobility components at short- to medium-term follow-up times. There are important concerns with polyethylene wear, late intra-prosthetic dislocation, and the lack of long-term follow-up data. Big femoral heads (36mm and 40mm) articulating with highly cross-linked, e-beam, remelted, polyethylene are a better choice in primary total hip arthroplasty, to decrease the frequency of dislocation in “high risk” patients. Although the risk of early dislocation was 4% in “high risk” patients, there was no recurrence, no revision, and no late first dislocation. Until further long-term results are available, caution is advised in the routine use of dual mobility components in primary total hip arthroplasty

The number one reason to consider large heads in total hip arthroplasty (THA) is for increased stability. Large diameter femoral heads substantially increase stability by virtue of increased range of motion and increased jump distance, which is the amount of displacement required to sublux the head out of the socket. Prevention is the best means for reducing dislocation, with requisites for stability being appropriate component position, restoration of leg length, and restoration of offset. In a review from our center studying the frequency of dislocation with small diameter femoral heads (≤32 mm) in 1262 patients (1518 hips) who underwent primary THA performed via a direct lateral approach, we observed a dislocation rate of 0.8% (12 of 1518). In a subsequent study of 1748 patients (2020 hips) who underwent primary THA at our center with large diameter heads (mean 43 mm, range 36–60 mm), we observed a substantially lower 0.04% frequency of dislocation (one of 2010) at a mean followup of 2.6 years. Our findings have been echoed in studies from several other centers. Howie et al. reported a prospective controlled trial of 644 low risk patients undergoing primary or revision THA randomised to receive either a 36 mm or 28 mm metal head articulated on highly crosslinked polyethylene. They observed significantly lower frequency of frequency of dislocation with 36 mm heads both overall (1.3%, 4 of 299 versus 5.4%, 17 of 216 with 28 mm heads, p=0.012) and in primary use (0.8%, 2 of 258 versus 4.4%, 12 of 275 with 28 mm heads, p=0.024), and a similar trend in their smaller groups of revision patients (5%, 2 of 41, versus 12%, 5 of 41 with 28 mm heads, p=0.273). Lachiewicz and Soileau reported on early and late dislocation with 36- and 40 mm heads in 112 patients (122 hips) at presumed high risk for dislocation who underwent primary THA. Risk factors were age >75 for 80 hips, proximal femur fracture for 18, history of contralateral dislocation for 2, history of alcohol abuse in 2, large acetabulum (>60 mm) in 6, and other reasons in 14. Early dislocation (<1 year) occurred in 4% (5 of 122), all with 36 mm heads. Late dislocation (>5 years) did not occur in any of the 74 patients with followup beyond 5 years. Stroh et al. compared 225 patients (248 hips) treated with THA using small diameter heads (<36 mm) to 501 patients (559 hips) treated with THA using large diameter heads (≥36 mm). There were no dislocations with large diameter heads compared with 1.8% (10 of 559) with small diameter heads. Allen et al. studied whether or not large femoral heads improve functional outcome after primary THA via the posterior approach in 726 patients. There were 399 done with small heads (<36 mm), 254 with medium heads (36 mm), and 73 with large heads (>36 mm), analyzed pre-operatively, at 6 months, and at 12 months. The authors could not find a correlation between increasing head size and improved function at one year, but observed that dislocation was reduced with large diameter heads. Optimization of hip biomechanics via proper surgical technique, component position, and restoration of leg length and offset are mandatory in total hip arthroplasty. Large heads enhance stability by increasing range of motion prior to impingement and enhancing jump stability

Introduction:. Non-invasive extendible endoprostheses (NIEE) were primarily developed for salvage after musculo-skeletal tumour surgery in the immature skeleton. However, they may also have a unique application to manage complex limb reconstruction in revision surgery to address limb-length inequality in the mature skeleton. The aim of this study is to present the minimum 2 –year results of using non-invasive extendible endoprostheses for complex lower limb reconstruction. Methods:. Between 2004 and 2013, 21 patients were treated with 23 NIEE. The indication for surgery was salvage of infected prosthesis following primary tumor resection in 6 cases, aseptic prosthesis failure after primary tumour resection in 5 cases, aseptic non-tumor prosthesis failure in 1 case, infected non-tumor prosthesis in 8 cases and symptomatic non-union of graft reconstruction in 3 cases. There were 14 male and 7 female patients with a mean age of 49.8 years (range 19–81). Results:. The mean length gained was 41.5 mm (range 0 to 90) requiring a mean of 7 (0–25) lengthening episodes performed in the outpatient department. 4 cases required revision surgery for persistent infection. These had multiple previous surgeries and inadequate soft tissue coverage. There were also 2 early dislocations in one patient treated successfully with lengthening and 1 failure to achieve desired length. The Mean Musculoskeletal Tumour Society rating score was 19. Conclusion:. The use of NIEE is associated with good functional outcome and offers yet another way of limb salvage. A modest complication rate is noted in this series, which reflects the complexity of these cases

We prospectively analyzed 83 patients who underwent ceramic-on-ceramic THA using preassembled (n = 22) or modular acetabular components (n = 61) between June 2010 and June 2012. No radiographic evidence of progressive radiolucency, osteolytic lesions, acetabular fractures, or component migration was detected in either group. Furthermore, no patient required revision surgery for instability or ceramic breakage. Table 1 shows the mean postoperative HHS, WOMAC score, and acetabular component inclination and anteversion in groups A and B. No significant differences in mean postoperative HHS (P < 0.056), WOMAC score (P < 0.258), acetabular component inclination (P < 0.827), or anteversion (P < 0.549) were observed between the two groups according to the independent sample t-test. However, the chi-square (Fisher's exact) test showed a significant difference between the two groups with respect to the gender of the patients (P < 0.001, Table 2). These findings indicate that half of the women had smaller acetabular diameters accommodating a cup size of only 48–50-mm. Thus a preassembled ceramic liner is a very good option for women with a small acetabulum, which could permit the use of a larger femoral head (36-mm) with thin-walled acetabular components. In contrast, the component-specific complications between the two groups were quite similar. One patient (group B) had transient squeaking that disappeared after a few months. One patient (group B) had a mild limp caused by abductor muscle weakness, and one patient (group B) had a superficial wound infection that was treated with local debridement and antibiotics. Early dislocation (P < 0.488) occurred in three patients (one in group A and two in group B). Two patients (one in group A and one in group B) reported postoperative falling events at their bedside. The other in group B was a female with rheumatoid arthritis, which can lead to a much higher risk of dislocation due to soft tissue laxity around the hip joint. All of these patients were treated by closed reduction without further incident. Three patients (one in group A and two in group B) had mild iliopsoas pain (P < 0.488) that was not associated with loosening; however, the pain did not limit their activities (Table 3). In conclusion, we found no significant differences in the mean postoperative radiographic or functional outcomes or complications between the two groups, showing satisfactory performance at the 2 year follow up. Only the gender of the patient was significantly different between the two goups, demonstrating that a larger number of women had smaller acetabular diameters accommodating a cup size of only 48–50-mm. Although a preassembled cup with a 36-mm ceramic liner has proven safety in the short term, future research should focus on its long-term risks

The number one reason to consider large heads in total hip arthroplasty (THA) is for increased stability. Large diameter femoral heads substantially increase stability by virtue of increased range of motion and increased jump distance, which is the amount of displacement required to sublux the head out of the socket. Prevention is the best means for reducing dislocation, with requisites for stability being appropriate component position, restoration of leg length, and restoration of offset. In a review from our center studying the frequency of dislocation with small diameter femoral heads (≤32 mm) in 1262 patients (1518 hips) who underwent primary THA performed via a direct lateral approach, we observed a dislocation rate of 0.8% (12 of 1518). In a subsequent study of 1748 patients (2020 hips) who underwent primary THA at our center with large diameter heads (mean 43 mm, range 36–60 mm), we observed a substantially lower 0.04% frequency of dislocation (one of 2010) at a mean followup of 2.6 years. Our findings have been echoed in studies from several other centers. Howie et al. reported a prospective controlled trial of 644 low risk patients undergoing primary or revision THA randomised to receive either a 36 mm or 28 mm metal head articulated on highly crosslinked polyethylene. They observed significantly lower frequency of frequency of dislocation with 36 mm heads both overall (1.3%, 4 of 299 versus 5.4%, 17 of 216 with 28 mm heads, p=0.012) and in primary use (0.8%, 2 of 258 versus 4.4%, 12 of 275 with 28 mm heads, p=0.024), and a similar trend in their smaller groups of revision patients (5%, 2 of 41 versus 12%, 5 of 41 with 28 mm heads, p=0.273). Lachiewicz and Soileau reported on early and late dislocation with 36- and 40 mm heads in 112 patients (122 hips) at presumed high risk for dislocation who underwent primary THA. Risk factors were age >75 for 80 hips, proximal femur fracture for 18, history of contralateral dislocation for 2, history of alcohol abuse in 2, large acetabulum (>60 mm) in 6, and other reasons in 14. Early dislocation (<1 year) occurred in 4% (5 of 122), all with 36 mm heads. Late dislocation (>5 years) did not occur in any of the 74 patients with follow up beyond 5 years. Stroh et al. compared 225 patients (248 hips) treated with THA using small diameter heads (<36 mm) to 501 patients (559 hips) treated with THA using large diameter heads (≥36 mm). There were no dislocations with large diameter heads compared with 1.8% (10 of 559) with small diameter heads. Allen et al. studied whether or not large femoral heads improve functional outcome after primary THA via the posterior approach in 726 patients. There were 399 done with small heads (<36 mm), 254 with medium heads (36 mm), and 73 with large heads (>36 mm), analyzed preoperatively, at 6 months, and at 12 months. The authors could not find a correlation between increasing head size and improved function at one year, but observed that dislocation was reduced with large diameter heads. Optimization of hip biomechanics via proper surgical technique, component position, and restoration of leg length and offset are mandatory in total hip arthroplasty. Large heads enhance stability by increasing range of motion prior to impingement and enhancing jump stability

Introduction. Dislocation is one of the most common orthopaedic complications after primary total hip replacement (THR). The reported dislocation rate in elective THR is 5–8%. This number increases up to 22% for THR done for neck of femur fractures. Due to the reported increase in dislocation for trauma, some surgeons prefer to do a hemi-arthroplasty or open reduction and internal fixation (ORIF). Hemi-arthroplasty is known to have poorer functional outcomes. Failure of ORIF is as high as 43%, and revision of failed ORIF to THR has reported dislocation rates of up to 42%. Materials and methods. A retrospective review of all THR done for neck of femur fractures during 2006–2011 was undertaken. The patients in our institution who are considered for a THR must have an active life-style. Records were reviewed for delay to surgery, surgical approaches, articulations, bearing surfaces, follow up periods and cemented versus uncemented implants. We excluded all pathological fractures, extra-capsular fractures, failed ORIF, patients with incomplete data and patients with a follow-up period less than 3 months. Hip dislocation was the end-point of the review and we did not study other causes of revision e.g. loosening of components or infection. Results. A total of 115 cases were identified as suitable for analysis. Average age at surgery was 73.2 years (range 30–81). Delay to surgery was 5.3 days (range 1–63). Average follow up period was 18.3 months (range 3 months-4,3years). Four patients (3.4%) had a confirmed dislocation. Three of these patients had successful closed reduction and one patient required revision surgery and change of component orientation. Conclusion. Our early dislocation rate of 3.4% is within the published results and shows that primary THR is an acceptable and safe option for displaced intracapsular NOF in active patients. Most recent studies have shown superior functional outcomes of THR compared to hemi-arthroplasty or poorly performed ORIF. NO DISCLOSURES

Introduction:. Dislocation is still one of the major complications in total hip arthroplasty. Among other factors, it is important to maximize the intended range of movement (iROM) in order to reduce the risk for prosthetic impingement and to prevent edge loading in order to avoid surface damage and squeaking. Therefore, both components should be positioned in accordance to the new combined safe-zone for correct combined version and inclination aiming for an optimal relative orientation of both components. This study shows how this optimal combined orientation of both components can be determined for a specific total hip prosthetic system and how the result can be transferred to surgery and accomplished intraoperatively using minimal-invasive stem-first technique. Material and Methods:. 829 minimal-invasive total hip arthroplasties have been performed from 2007 to 2013 in our institution. In all of these surgeries a minimal-invasive direct anterior approach (DAA) was applied. All patients were positioned supine on a proprietary orthopedic table. In 168 cases a system-specific mechanical aiming device was used intraoperatively in order to control the combined version and inclination according to the specific safe-zone by orienting the prosthetic socket in relation to the prosthetic stem. This is called “stem-first technique” meaning that the prosthetic stem dictates the orientation of the socket. It does not mean the sequence of implantation. It's specific advantage is that the stem redirects the socket if it's position is modified. It equally applies to standard, anatomic (Fig. 1) or short stems (Fig. 2). The socket orientation is not primarily referred to bony landmarks of the pelvis but to the neck of the stem. Nevertheless the surgeon has to look for sufficient fixation of the socket within the acetabular bone. Leg length was measured in the surgical field additionally and prosthetic offset was adjusted according to the preoperative planning. All other patients were operated on in our standard minimal-invasive DAA-procedure. The majority of the patients suffered from osteoarthritis, their mean age was 68 years. Results:. Optimal component orientation for each prosthesis system was derived from its 3D-model by simulating hip joint motion in the physiologic range of motion. Optimal component orientation means maximizing the area of the combined safe-zone. In the stem-first group cup orientation was in the new combined safe-zone in 94% of the cases and no squeaking or prosthetic impingement did occur in any of these patients. Leg length did not differ more than +/− 5 mm. 83% of all patients receiveda ceramic-on-ceramic articulation, one early dislocation did occur and treated by closed reduction. Conclusion:. Stem-first technique is ideally suited for the minimal-invasive direct anterior approach in total hip arthroplasty to control the combined orientation of the prosthetic components and to achieve excellent clinical results. It assists the surgeon in aligning the cup and the stem according to their correct combined orientation in order to get an optimal range of movement especially in young patients

We undertook a comparative audit of 171 consecutive Hip and Knee Arthroplasties performed by an overseas team at an Independent Hospital (Group 1) between August 2005 and December 2005 and compared them to a corresponding number performed by all grades of surgeons at the local NHS Trust (Group 2). We examined patient selection criteria such as BMI and ASA grade and compared the early radiological outcome, complication rate, length of hospital stay and the patient satisfaction rate between the two groups. We found that patients in Group 1 had a lower average BMI (27.13) and a better ASA grade (95% grade 1 and 2) as compared to Group 2 (BMI - 29.69 and 80% ASA Grade 1 and 2). The average hospital stay was 6.1 days in Group 1 and 8 days in Group 2. Only 74% of the patients in Group 1 were completely satisfied with their treatment outcome as compared to 91% in Group 2. (Trent Arthroplasty Questionnaire). There were 7 early dislocations (9.1%) in Group 1 (76 THRs), two requiring revision, as compared to one in Group 2 (1.3%, 84 THRs). Three other patients from Group 1 (TKRs) required a revision procedure within the first year. There was an increased incidence of adverse features (mal-alignment and mal-positioning of components) on the post operative X rays of patients in Group 1 as compared to Group 2 leading to adverse clinical events. 11 patients (95TKRs) showed substantial femoral notching in Group 1 as compared to 3 in Group 2. This study shows that patients selected for surgery by the overseas team were the fitter of the two groups, but had a significantly higher complication rate and a much lower satisfaction rate. The study underlines the potential risks of commissioning work to overseas teams in order to reduce waiting times

Bone preserving hip arthroplasty devices are appealingfor use in young patients because their high-demand activities and extended lifetimes makes the prospect of multiple revisions a reality. Therefore prostheses which ensure a straightforward revision with a low complication rate and good clinical outcome are favourable for young and active patients. Modern hip resurfacing serves these conditions and shows very good mid-term and now longer term (10 and 13 years) results especially in osteoarthritis. With other diagnoses like avascular necrosis, deformities of the femoral head in m. Perthes or slipped femoral epiphysis (SUFE), or in large bone cysts and erosive arthritis the bone stock of the femoral head gives insufficient support to the femoral component. In these conditions the alternative to a resurfacing procedure had been a stemmed total hip arthroplasty (THA). The Birmingham Mid Head Resection device (BMHR; Smith&Nephew Orthopaedics) is an alternative to resurfacing and to a stemmed THA. The BMHR device consists of an uncemented short stem made of titanium alloy and a large diameter cobalt-chrome head. The stem does not enter the femoral canal thus facilitating future revisions. The metal-on-metal bearing is the same as in resurfacing. The instrumentation allows switching from a planned BHR to the BMHR. The BMHR uses the unique anatomy of the head neck junction to prepare internally a cone that matches the frustoconical section of the BMHR stem. Thus a cement free press fit can be achieved. This maintains anatomical load transmission and avoids osteopenia of the proximal fenur. Since 2006 we have performed 662 BMHR implantations. The indications were osteoarthritis in about 70%, dysplasia in 20%, AVN 5,5%, posttraumatic OA in 3%, SUFE and m. Perthes in 1%. Complications occured in 3,2%. Fractures of the femoral neck occured in 8 patients, 4 of them caused by technical errors in the beginning, 3 because of higher risk indication. All revisions were performed successfully and the cup was retained. Low grade infections in 2 cases with one stage revision and 3 unstable cups needed to be reinserted. All revisions were successful. One early dislocation was treated by closed reduction, another remained unstable and was treated by THA. In conclusion we continue to use the BMHR to bridge the gap between resurfacing and stemmed THA because the complications we experienced are not inevitable and had become very rare with our growing experience

The aim of this retrospective and mono centric study is to expose results and complications of the reverse concept in the elderly in case of trauma. We therefore ask whether clinically the patients recover a pre-broken state, whether the radiological follow-up shows critical images and whether the rate of complications is important. We reviewed the outcome of forty-two patients operated consecutively by the same surgeon at a mean follow-up of 9.1 years (range, 1–19 years). There were four men and thirty-eight females, mean age 75 (range, 58–92 years), with 28 complex four-part fractures and 14 fracture-dislocations. There was no re-fixation of the tubercles because of a poor bone quality. Six complications occurred: 2 complex sympathetic dystrophies treated by medication, 2 early dislocations (one superior because of an impingement in adduction between the humeral stem and the remnants of the tubercles solved by their ablation without further problems and one anterior caused by the voluntary 10° ante-version of the humeral component to improve internal rotation leading to the reorientation of the stem), 1 deep infection solved by debridement and drainage for an early postoperative Acinetobacter infection without further problems and one aseptic loosening of the base-plate with a broken screw and no wear at 12-year follow-up leading to implant a classic base-plate because of a fair bone stock and efficient primary grip after impaction. The mean Constant score dropped from 55 at one year to 52 (20 to 84) at last revision which represented 67% of the mean score for the injured side. Mean adjusted Constant score was 68. Only 58% of the patients were satisfied or very satisfied because of poor rotations avoiding nourishment with utensils, dressing andpersonal hygiene. When the dominant arm was affected, the patients lost frequently their autonomy. Two patients with 42-mm glenospheres had complete 2-mm radiolucent lines at four- and eight-year follow-up. Inferior spurs were seen in 15 cases (35%). They were stable after emergence without functional impact or radiographic evolution. They appeared at a mean of 2.5 years (range, 1–6 years). Scapular notching was seen in 23 cases (55% of the patients), all appeared before two-year follow-up. Eleven notches were stable with a sclerotic border and without critical humeral images. Twelve were progressive with a proximal humeral bone loss (n = 7) or a radiolucent line (n = 5). In these cases, there was a negative effect on the Constant score: 41 points instead of 57 for notches without critical images. Our experience reported in the present study has somewhat weakened our enthusiasm for this procedure. 42% of the patients were unsatisfied because of poor rotations and the functional results were never equal to the pre-injury state. 33% of the radiological images found were critical. 14% of the patients had a severe complication. Such results do not allow us to validate in the long-term the concept of RSA in recent trauma of proximal humerus. So nowadays, our elective indication is a woman for a non-dominant arm, over seventy years old with poor physiology and important osteoporosis