Postoperative dislocation following total hip arthroplasty (THA) remains a significant concern with a reported incidence of 1% to 10%. The risk of dislocation is multifactorial and includes both surgeon-related (i.e. implant position, component size, surgical approach) and patient-related factors (i.e. gender, age, preoperative diagnosis, neurologic disorders). While the majority of prior investigations have focused on the importance of acetabular component positioning, recent studies have shown that approximately 60% of “dislocators” following primary THA have an acceptably aligned acetabular component. Therefore, the importance of the relationship between the spine and pelvis, and its impact on functional component position has gained increased attention.

Kanawade and Dorr et al. have shown patients can be categorised into having a stiff, normal, or hypermobile pelvis based on their change in pelvic tilt when moving from the standing to seated position. The degree of change in functional position of both the acetabular and femoral components is impacted by the degree of pelvic motion each patient possesses. In the “normal” pelvis, as a patient moves from the standing to seated position the pelvis typically tilts posteriorly, thus increasing the functional anteversion of the acetabular component. However, patients with lumbar degeneration or spine pathology often have a decrease in posterior pelvic tilt in the seated position, thus potentially increasing their risk of dislocation. Bedard et al. noted an 8.3% dislocation risk in patients with a spinopelvic fusion after THA vs. 2.9% in those without.

There is the potential that preoperative, dynamic imaging can be used to predict the ideal component position for each individual patient undergoing THA. However, this assumes that a patient's preoperative pelvic motion will be the same following implantation of a total hip prosthesis, and that a patient's pelvic motion will remain consistent over time postoperatively. A recent study has shown that the impact of THA on pelvic motion can be highly variable, thus potentially limiting the utility of preoperative dynamic imaging in predicting a patient's ideal component position. Future investigations must focus on preoperative factors that can be used to predict postoperative pelvic motion and how pelvic motion changes over time following implantation of a total hip arthroplasty.

Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian Registry Study where 68447 patients were identified for having a hip hemiarthroplasty from 2012-2020. This is a retrospective cohort study, identifying patients that had cementless or cemented hip hemiarthroplasty. The surgeons who performed the procedures were linked to the procedure Total Hip Replacement. Individuals were categorized as experienced hip surgeons or not based on whether they performed 50 hip replacements a year. Identifying high volume surgeon (>50 cases/year) and low volume (<50 cases/year) surgeons. Hazard ratios adjusted for age and sex were performed for risk of revision over this 8-year span. A p-value <0.05 was deemed significant. For high volume surgeons, cementless fixation had a higher revision risk than cemented fixation, HR 1.29 (1.05-1.56), p=0.017. This pattern was similar for low volume surgeons, with cementless fixation having a higher revision risk than cemented fixation, HR 1.37 (1.11-1.70) p=0.004 We could not detect a difference in revision risk for cemented fixation between low volume and high volume surgeons; at 0-1.5 years the HR was 0.96 (0.72-1.28) p=0.786, and at 1.5+ years the HR was 1.61 (0.83-3.11) p=0.159. Similarly, we could not detect a difference in revision risk for cementless fixation between low volume and high volume surgeons, HR 1.11 (0.96-1.29) p=0.161. Using large registry data, cemented hip hemiarthroplasty has a significant lower revision rate than the use of cementless stems even when surgeons are stratified to high and low volume. Low volume surgeons who use uncemented prostheses have the highest rate of revision. The low volume hip surgeon who cements has a lower revision rate than the high volume cementless surgeon. The results of this study should help to guide surgeons that no matter the level of experience, using a cemented hip hemiarthroplasty for acute femoral neck fracture is the safest option. That high volume surgeons who perform cementless hemiarthroplasty are not immune to having revisions due to their technique. Increased training and education should be offered to surgeons to improve comfort when using this technique

Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian Registry Study where 68447 patients were identified for having a hip hemiarthroplasty from 2012-2020. This is a retrospective cohort study, identifying patients that had cementless or cemented hip hemiarthroplasty. The surgeons who performed the procedures were linked to the procedure Total Hip Replacement. Individuals were categorized as experienced hip surgeons or not based on whether they performed 50 hip replacements a year. Identifying high volume surgeon (>50 cases/year) and low volume (<50 cases/year) surgeons. Hazard ratios adjusted for age and sex were performed for risk of revision over this 8-year span. A p-value <0.05 was deemed significant. For high volume surgeons, cementless fixation had a higher revision risk than cemented fixation, HR 1.29 (1.05-1.56), p=0.017. This pattern was similar for low volume surgeons, with cementless fixation having a higher revision risk than cemented fixation, HR 1.37 (1.11-1.70) p=0.004 We could not detect a difference in revision risk for cemented fixation between low volume and high volume surgeons; at 0-1.5 years the HR was 0.96 (0.72-1.28) p=0.786, and at 1.5+ years the HR was 1.61 (0.83-3.11) p=0.159. Similarly, we could not detect a difference in revision risk for cementless fixation between low volume and high volume surgeons, HR 1.11 (0.96-1.29) p=0.161. Using large registry data, cemented hip hemiarthroplasty has a significant lower revision rate than the use of cementless stems even when surgeons are stratified to high and low volume. Low volume surgeons who use uncemented prostheses have the highest rate of revision. The low volume hip surgeon who cements has a lower revision rate than the high volume cementless surgeon. The results of this study should help to guide surgeons that no matter the level of experience, using a cemented hip hemiarthroplasty for acute femoral neck fracture is the safest option. That high volume surgeons who perform cementless hemiarthroplasty are not immune to having revisions due to their technique. Increased training and education should be offered to surgeons to improve comfort when using this technique

Aim. A septic revision of an artificial joint is routinely split up in a so-called dirty phase and a clean phase. The measures taken to initiate the start of the clean phase vary significantly between musculoskeletal infection centers. We performed simulations of one-step exchanges of infected THAs and sought to 1) determine the effect of different clean phase protocols on the sterile field, and 2) determine whether or not it is possible to re-implant the new prosthesis completely clean. Method. Nine fresh frozen cadaveric hips were used and primary THA was undertaken via a direct anterior approach. Before implantation of the components varying amounts of fluorescent powder (GloGerm) were deposited, simulating bacterial infection. Second, a one-step exchange was performed via a posterolateral approach. After implant removal, debridement, and lavage, randomization determined which clean phase protocol was followed, i.e. no, some or full additional measures. Finally, the new prosthesis was re-implanted (fig. 1). In order to determine the effect of different clean phase protocols on contamination of the sterile field standardized UV light-enhanced photographs were obtained of 1) the gloves, 2) the instrument table, 3) the drapes, and 4) the wound and these were ranked on cleanliness by a blind panel of hip surgeons. In order to determine whether or not it is possible to re-implant the prosthesis completely clean, the implant was taken out again at the end of the one-step exchange and inspected for contamination under UV light. Results. The gloves, the instrument table, the drapes (fig. 2) and the wound were significantly cleaner after a clean phase using full additional measures compared to partial or no additional measures (p < 0.000). Partial measures were able to reduce some of the contamination of the gloves and the wound, but had no effect on the drapes and the instrument table. All re-implanted implants were contaminated with some amount of fluorescent powder at the end of the one-step exchange. Conclusions. We advise to incorporate a clean phase with full additional measures into the surgical treatment of prosthetic joint infections, as the effect of partial measures seems to be a poor compromise. The results of this study have now been published: Vles G, Bossen J, Kloos J, Debeer P, Ghijselings S. On the value and limitations of incorporating a “clean phase” into the surgical treatment of prosthetic joint infections - an illustrative cadaveric study using fluorescent powder. J Exp Orthop. 2022 Mar 21;9(1):28. doi: 10.1186/s40634-022-00467-x

The use of total hip arthroplasty in adolescents for end-stage degenerative hip disease is controversial with few reported outcomes in the literature. The purpose of the study was to report the outcomes of total hip arthroplasty in a cohort of adolescents managed by a multidisciplinary team of paediatric and adult orthopaedic surgeons from a single centre. A multidisciplinary clinic consisting of paediatric and adult hip surgeons was established in 2013 to identify, treat and prospectively follow adolescents who would potentially beneift from a total hip arthoplasty. To date 29 consecutive adolescent patients (20 female, 9 male, 32 hips) with end stage degenerative hip disease have undergone cementless primary total hip arthroplasty. Mean age at decision to treat was 15.7 years (age 11.4–18.5). Ten different underlying paediatric specific pathologies were documented including DDH, cerebral palsy, JIA, skeletal dysplasias, SCFE and idiopathic chondrolysis. Three patients had bilateral staged procedures. Clinical baseline and outcomes were measured using Oxford Hip Score (OHS), WOMAC score and ASKp scores. Radiographic follow-up was conducted at 6 weeks, 6 months and yearly thereafter. Post-operative complications were recorded. Twenty-five hips were eligible for minimum 2-year follow-up scoring at a mean 2.7 years (2.0–3.6 years). No intraoperative complications occurred. One case of recalcitrant postoperative psoas tendonitis occured. OHS improved from 25 (7–43) to 41 (23–48). WOMAC improved from 48 (12–8) to 12 (1–44), and ASKp improved from 78% (33–98%) to 93% (73–100%). Radiographic review revealed acceptable alignment of all components with no signs of loosening or wear. No revision of components was required. One patient died at 6 months post op from an unrelated condition. The early term results of total hip arthroplasty in adolescents from our multidisciplinary program are encouraging. Improvements in quality of life to normal values were seen as were hip scores consistent with satisfactory joint function. Depite the range of complex and varied causes of arthritis seen in this population the establishment of combined paediatric and adult orthopaedic surgical teams appears to be a successful model to manage end-stage degenerative hip disease in adolescents

Aims

Our primary aim was to establish the proportion of female orthopaedic consultants who perform arthroplasty via cases submitted to the National Joint Registry (NJR), which covers England, Wales, Northern Ireland, the Isle of Man, and Guernsey. Secondary aims included comparing time since specialist registration, private practice participation, and number of hospitals worked in between male and female surgeons.

The ideal operative treatment of displaced sub capital femoral fractures in the elderly is controversial. Recently, randomised controlled trials have suggested a better outcome with the use of total hip arthroplasty (THA) to treat displaced intra capsular fractures of the femur for elderly patients in good health. More recently the concept of dual mobility cups is being promoted to avoid dislocations in this cohort of patients. However, overall there is limited evidence to support the choice between different types of arthroplasty. Dislocation remains a main concern with THA, especially when a posterior approach is used. We analysed the outcome of 115 primary THR (112 cements and 3 uncemented) THR using a posterior approach with soft tissue repair in active elderly patients presenting with displaced intra capsular femoral neck fractures. Size 28 mm head was used in 108 and a size 32 mm head in the rest. All surgery was performed by specialist hip surgeons. Satisfactory results were noted in terms of pain control, return to pre-morbid activity and radiological evidence of bone implant osteo-integration. The 30-day mortality was nil. There were two dislocations and only one needed revision surgery due to recurrent dislocation. In conclusion, with optimal patient selection, THA seems to provide a good functional outcome and pain relief in the management of displaced intracapsular femoral neck fractures. Excellent outcome can be achieved when done well using the standard cemented THR and with 28mm head. A good soft tissue repair and a specialist hip surgeon is preferable

The challenges faced by hip surgeons have changed over the last decade. Historically, fixation, polyethylene wear, osteolysis, loosening and failure to osseointegrate dominated the discussions at hip surgery meetings. With the introduction of highly crosslinked polyethylene, wear and osteolysis are currently not significant issues. Improved surgical technique has resulted in a high rate of osseointegration and once fixed, loosening of cementless components is rare. In this session, we will focus on issues that orthopaedic surgeons performing hip surgery routinely face including bearing couples in the young active patient, implant choices in the dysplastic hip and osteoporotic femur, evaluation and management of the unstable hip and differential diagnosis of the painful THR

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 or ceramic head is snap-fit into the large polyethylene. In some European centers, these components are routinely used for primary total hip arthroplasty. However, their greatest utility will be to prevent and manage recurrent dislocation in the setting of revision total hip arthroplasty. Several retrospective series have shown satisfactory results for this indication at medium-term follow-up times. The author has used dual mobility components on two occasions to salvage a failed constrained liner. At least one center reports that dual mobility outperforms 40mm femoral heads in revision arthroplasty. Modular dual mobility components, with screw fixation, are the author's first choice for the treatment of recurrent dislocation, revision of failed metal-on-metal resurfacing or total hips, unipolar arthroplasties, and salvage of failed constrained liners. There are concerns of elevated metal levels with one design, and acute early intra-prosthetic dissociation following attempted closed reduction. Total hip surgeons no longer use conventional polyethylene, autologous blood donation, or a hemovac drain; now constrained components join these obsolete techniques! In 2018, a dual mobility component, rather than a constrained liner, is the preferred solution in revision surgery to prevent and manage recurrent dislocation

Acetabular implant position is important for the stability, function, and long-term wear properties of a total hip arthroplasty (THA). Prior studies of acetabular implant positioning have demonstrated a high percentage of outliers, even in experienced hip surgeons, when conventional instruments are used. Computer navigation is an attractive tool for use in (THA, as it has been shown to improve the precision of acetabular component placement and reduce the incidence of outliers. However, computer navigation with imageless, large-console systems is costly and often interrupts the surgeon's workflow, and thus, has not been widely adopted. Another method to improve acetabular component positioning during THA is the use of fluoroscopy with the direct anterior approach. Studies have demonstrated that the supine position of the patient during surgery facilitates the use of fluoroscopic guidance, thus improving acetabular component position. A handheld, accelerometer based navigation unit for use in total hip replacement has recently become available to assist the surgeon in positioning the acetabular component during anterior approach THA, potentially reducing the need for intraoperative fluoroscopic studies. We sought to compare the radiographic results of direct anterior THA performed with conventional instrumentation vs. handheld navigation to determine the accuracy of the navigation unit, and to see whether or not there was a reduction in the fluoroscopic time used during surgery. Furthermore, we timed the use of the navigation unit to see whether or not it required a substantial addition to surgical time. Our results demonstrate that a handheld navigation unit used during anterior approach THA had no difference with regard to acetabular cup positioning when compared to fluoroscopically assisted THA, but led to a reduction in the use of intraoperative fluoroscopy time

OBJECTIVE. Debridement, Antibiotics and Implant Retention (DAIR) procedure is well established for Prosthetic Joint Infection (PJI) in acute setting after total hip and knee replacements. We present our perspective of DAIR in a relatively a small cohort following hip and knee replacements in a District General Hospital (DGH) in United Kingdom, where we delivered comparable results to leading tertiary centers in short to mid-term followup. METHODS. We undertook a retrospective study involving 14 patients, who underwent DAIR in our DGH between August 2012 and December 2015. Patient cohort included primary, complex primary and revision hip and knee replacements. Multiple samples were taken intraoperatively for cultures and histology. mMicrobiological support was provided by a microbiologist with interest in musculoskeletal infections. RESULTS. 14 patients [9 males, 5 females; age 62–78 years (Mean 70.7); BMI 22–44.2 (Mean 33.8)] with multiple comorbidities underwent DAIR procedure within 3 weeks of onset of symptoms, (although the time from index surgery ranged from 15 days to 58 months). Patient selection was made by two Hip surgeons. 12 out of 14 grew positive cultures with two growing Vancomycin resistant Enterococcus. IV antibiotics were stated after samples intraoperatively and continued in six patients after discharge using (OPAT), while 8 were discharged with oral antibiotics. One patient died in immediate post operative period due to generalised sepsis. Another patient died of myocardial infarction 2 years after DAIR. 12 (85.7%) patients are doing well with regular followup (Mean 20 months) in clinics. CONCLUSIONS. With good patient selection, DAIR is a far simpler solution and a safe and reproducible surgical option in PJI in hip and knee replacements compared to one or two stage revisions with the implications. But published Data in contemporary literature is predominantly from specialized centers. Our small series provides a perspective of early to mid term results of DAIR from a DGH

Introduction. The shuck test was widely used to assess the overall soft-tissue tension around the hip joint during surgery. There have been few attempts to standardize how one evaluates soft tissue tension in total hip arthroplasty. The aim of this study was to ask how reliable the shuck test was as a measure of soft tissue tension in total hip arthroplasty. Methods. First, we assessed the intra- and inter-examiner variability of the force generated in the shuck test. Next, we asked how the strength of traction forces and joint position on the distance of displacement of the prosthetic head at surgery. Twenty-one hip surgeons, consisting of seven experienced hip surgeons, seven junior hip surgeons, and seven surgeons in training were included in the first study. Test subjects were instructed to pull a traction gauge with their customary range of force. Each subject performed two sets of the shuck test in one week interval. Eighteen patients who had cementless THA through postero-lateral approach using 3D-CT based navigation system were enrolled in the second study. After implantation of components, the leg was pull caudally using our original device [Fig. 1]. The strength of applied traction force was 20 %, 30 %, 40 % and 50 % of body weight of each patient. The distance of displacement of a prosthetic head during traction was recorded at flexion angles of 0, 15, 30 and 45 degrees using the navigation system. Internal or external rotation of legs was controlled within 5 degrees. Results. There was a significant difference among examiners in the range of force generated in shuck test. The mean force was 24.1 kg (SD; 6.4, range; 11 to 35). There was no significant difference in the range of force among experienced, junior surgeons and surgeons in training (p=0.11). Intra-class correlation between the tests and re-tests was 0.8. The distance of displacement of prosthetic heads during traction increased with traction forces significantly (p=0.001). There were significant differences in the distance of displacement of prosthetic heads during traction among flexion angles (p=0.001). The femoral head displaced most at the flexion angle of 15 degrees. Conclusion. There were considerable inter-examiner differences in the range of forces generated by the shuck test. The strength of traction forces and flexion angles influenced significantly the distance of displacement of prosthetic heads. It is necessary to standardize the strength of traction forces and flexion angles in order to make the shuck test reliable

The number of cemented femoral stems implanted in the United States continues to slowly decrease over time. Approximately 10% of all femoral components implanted today are cemented, and the majority are in patients undergoing hip arthroplasty for femoral neck fractures. The European experience is quite different. In the UK, cemented femoral stems account for approximately 50% of all implants, while in the Swedish registry, cemented stems still account for the majority of implanted femoral components. Recent data demonstrating some limitations of uncemented fixation in the elderly for primary THA, may suggest that a cemented femoral component may be an attractive alternative in such a group. Two general philosophies exist with regards to the cemented femoral stem: Taper slip and Composite Beam. There are flagship implants representing both philosophies and select designs have shown excellent results past 30 years. A good femoral component design and cementing technique, however, is crucial for long-term clinical success. The author's personal preference is that of a “taper slip” design. The cemented Exeter stem has shown excellent results past 30 years with rare cases of loosening. The characteristic behavior of such a stem is to allow slight subsidence of the stem within the cement mantle through the process of cement creep. One or two millimeters of subsidence in the long-term have been observed with no detrimental clinical consequences. There have been ample results in the literature showing the excellent results at mid- and long-term in all patient groups. The author's current indication for a cemented stem include the elderly with no clear and definitive cutoff for age, most likely in females, THA for femoral neck fracture, small femoral canals such as those patients with DDH, and occasionally in patients with history of previous hip infection. Modern and impeccable cement technique is paramount for durable cemented fixation. It is important to remember that the goal is interdigitation of the cement with cancellous bone, so preparing the femur should not remove cancellous bone. Modern technique includes distal plugging of the femoral canal, pulsatile lavage, drying of the femoral canal with epinephrine or hydrogen peroxide, retrograde fill of the femoral canal with cement with appropriate suction and pressurization of the femoral cement into the canal prior to implantation of the femoral component. The dreaded “cement implantation syndrome” leading to sudden death can be avoided by appropriate fluid resuscitation prior to implanting the femoral component. This is an extremely rare occurrence today with reported mortality for the Exeter stem of 1 in 10,000. A cemented femoral component has been shown to be clinically successful at long term. Unfortunately, the art of cementing a femoral component has been lost and is rarely performed in the US. The number of cemented stems, unfortunately, may continue to go down as it is uncommonly taught in residency and fellowship, however, it might find a resurgence as the limits of uncemented fixation in the elderly are encountered. National joint registers support the use of cemented femoral components, and actually demonstrate higher survivorship at short term when compared to all other uncemented femoral components. A cemented femoral component should be in the hip surgeons armamentarium when treating patients undergoing primary and revision THA

Acetabular implant position is important for the stability, function, and long-term wear properties of a total hip arthroplasty (THA). Prior studies of acetabular implant positioning have demonstrated a high percentage of outliers, even in experienced hip surgeons, when conventional instruments are used. Computer navigation is an attractive tool for use in THA, as it has been shown to improve the precision of acetabular component placement and reduce the incidence of outliers. However, computer navigation with imageless, large-console systems is costly and often interrupts the surgeon's workflow, and thus, has not been widely adopted. Another method to improve acetabular component positioning during THA is the use of fluoroscopy with the direct anterior approach. Studies have demonstrated that the supine position of the patient during surgery facilitates the use of fluoroscopic guidance, thus improving acetabular component position. A handheld, accelerometer-based navigation unit for use in total hip replacement has recently become available to assist the surgeon in positioning the acetabular component during anterior approach THA, potentially reducing the need for intra-operative fluoroscopic studies. We sought to compare the radiographic results of direct anterior THA performed with conventional instrumentation vs. handheld navigation to determine the accuracy of the navigation unit, and to see whether or not there was a reduction in the fluoroscopic time used during surgery. Furthermore, we timed the use of the navigation unit to see whether or not it required a substantial addition to surgical time. Our results demonstrate that a handheld navigation unit used during anterior approach THA had no difference with regard to acetabular cup positioning when compared to fluoroscopically assisted THA, but led to a reduction in the use of intra-operative fluoroscopy time

The challenges faced by hip surgeons have changed over the last decade. Historically, fixation, polyethylene wear, osteolysis, loosening and failure to osseointegrate dominated the discussions at hip surgery meetings. With the introduction of highly crosslinked polyethylene, wear and osteolysis are currently not significant issues. Improved surgical technique has resulted in a high rate of osseointegration and once fixed, loosening of cementless components is rare. In this section, we will focus on issues that orthopaedic surgeons performing hip surgery routinely face including bearing couples in the young active patient, implant choices in the dysplastic hip and osteoporotic femur, evaluation and management of the unstable hip and differential diagnosis of the painful THR

The anterior pelvic plane (APP) angle is often used as a reference to decide pelvic alignment for hip surgeons. However, Rousseau criticised the validness of the APP angles because the APP angles in standing position measured on conventional standing X-ray films never showed correlation with the other pelvic alignment parameters, such as sacral slope (SS). We measured the APP angles, SS and pelvic tilt (PT) on the non-distorted anteroposterior (AP) and lateral digitally reconstructed radiography (DRR) images in supine position (with CT scans) and AP and lateral X-ray images in standing position (with EOS X-ray machine [EOS imaging, Paris, France]) by using of the same EOS software. Our data showed that the pre- and post-operative APP angles correlated with SS and PT in both supine and standing positions. Our non-distorted high quality images and the EOS software revealed these correlations. Therefore, we can still use the APP angles to decide pelvic alignment for patients who undergo total hip arthroplasty (THA). Recent papers demonstrated positional or chronological dramatic changes of the APP angles between pre- and post-operative states in patients who underwent THA. The EOS system will be a powerful tool to investigate these changes of the pelvic alignments

Total hip arthroplasty (THA) has been cited as one of the most successful surgical procedures performed today. However, as hip surgeons, we desire constantly improving outcomes for THA patients with more favorable complication rates. At the same time, patients desire hip pain relief and return to function with as little interruption of life as possible. The expectation of patients has changed; they have more physical demands for strength and flexibility, and aspire to achieve more in their recreational pursuits. Additionally, health care system constraints require the THA episode of care to become more efficient as the number of procedures increases with time. These factors, over the past fifteen years, have led to a search for improved surgical approaches and peri-operative pain and rehabilitation protocols for primary THA. The orthopaedic community has seen improved pain control, length of stay, and reduction in complications with changes in practice and protocols. However, the choice of surgical approach has provided significant controversy in the orthopaedic literature. In the 2000s, the mini-posterior approach (MPA) was demonstrated as the superior tissue sparing approach. More recently, there has been a suggestion that the direct anterior approach (DAA) leads to less muscle damage, and improved functional outcomes. A recent prospective randomised trial has shown a number of early deficits of the posterior approach when compared to the direct anterior approach. The posterior approach resulted in patients taking an additional 5 days to discontinue a walker, discontinue all gait aids, discontinue narcotics, ascend stairs with a gait aid, and to walk 6 blocks. Patients receiving the posterior approach required more morphine equivalents in the hospital, and had higher VAS pain scores in the hospital than the direct anterior approach. Interestingly, activity monitoring at two weeks post-operatively also favored DAA with posterior approach patients walking 1600 steps less per day than DAA patients. There has been little difference in the radiographic outcomes or complications between approaches in prospective randomised trials. A number of randomised clinical trials have demonstrated that both the direct anterior and posterior approach provided excellent early post-operative recovery with a low complication rate. DAA patients have objectively faster recovery with slightly shorter times to achieve milestones of function, with similar radiographic and clinical outcomes at longer-term outcomes, with a similar complication rate

Introduction. While THA is associated with positive results and long-term improvement in patient quality of life, outcomes are nonetheless associated with adverse events and post-procedural deficits related to discrepancies in leg length (LLD), offset and cup placement. Post-THA errors in these parameters are associated with gait alteration, low back pain and patient dissatisfaction. Such discrepancies often necessitate revision and increasingly lead to medical malpractice litigation. Maintaining accuracy in post-surgical leg length, offset and cup placement during THA is difficult and subject to error. The sensitivity of these factors is highlighted in studies that have shown that a change of as little as 5 degrees of flexion or abduction can induce alterations in leg length of up to several millimeters. Similarly, positioning of implants can alter global and femoral offset, affecting abductor strength, range of motion and overall physical function. Compounding the biochemical issues associated with inaccurate leg length are the costs associated with these deficits. Traditional freehand techniques of managing intra-operative parameters rely on surgeon experience and tissue tensioning to manually place components accurately. These methods, however, are only able to assess leg length and are subject to inaccuracies associated with patient movement or orientation changes during surgery. Mechanical methods of minimizing post-surgical discrepancies have been developed, such as outrigger or caliper devices, although these methods also address leg length only and provide poor feedback regarding offset and center of rotation, therefore providing insufficient data to accurately achieve appropriate post-surgical leg length. Computer-assisted navigation methods provide more data regarding leg length, offset and center of rotation, but are limited by their cumbersome nature and the large capital costs associated with the systems. The Intellijoint HIP. ®. surgical smart tool (Intellijoint Surgical, Inc., Waterloo, ON) is an intra-operative guidance tool that provides surgeons with real time data on leg length, offset and center of rotation, thereby allowing for confident selection of the correct implant in order to ensure appropriate post-surgical biomechanics. The early clinical results from an initial cohort of patients indicate that Intellijoint HIP. ®. is safe and effective. No adverse events were reported in the initial cohort, and the smart tool was able to measure surgical parameters to within 1mm when compared to radiographic measurements. With training cases removed, 100% of cases had a post-procedure leg length discrepancy of less than 5mm. This paper describes the indications, procedural technique and early clinical results of the Intellijoint HIP. ®. smart tool, which offers a safe, accurate and easy-to-use option for hip surgeons to manage leg length, offset and cup position intra-operatively

Patients with neuromuscular disease and imbalance present a particularly challenging clinical situation for the orthopaedic hip surgeon. The cause of the neuromuscular imbalance may be intrinsic or extrinsic. Intrinsic disorders include those in which the hip is in development, such as cerebral palsy, polio, CVA, and other spinal cord injuries and disease. This can result in subluxation and dislocation of the hip in growing children, and subsequent pain, and difficulty in sitting and perineal care. Extrinsic factors involve previously stable hips and play a secondary role in the development of osteoarthritis and contractures in later life. Examples of extrinsic factors are Parkinson's disease, dyskinesis, athetosis, and multiple sclerosis. Goals of treatment in adults with pain and dysfunction in the setting of neuromuscular imbalance are to treat contractures and to perform salvage procedures to improve function and eliminate pain. Treatment of patients with neuromuscular imbalance may include resection arthroplasty (Girdlestone), arthrodesis, or total hip arthroplasty. Resection arthroplasty is typically reserved for patients that are non-ambulatory, or hips that are felt to be so unstable that arthroplasty would definitely fail due to instability. In modern times arthrodesis has limited use as it negatively impacts function and self-care in patients with neuromuscular disorders. Total hip arthroplasty has the ability to treat pain, relieve contractures, and provide improved function. Due to the increased risk of instability, special considerations must be made during primary total hip arthroplasty in this patient cohort. Risk of instability may be addressed by surgical approach, head size, or use of alternative bearing constructs. Posterior approach may have increased risk of posterior dislocation in this patient group, particularly if a posterior capsular repair is not possible due to the flexion contractures and sitting position in many patients. Surgeons familiar with the approaches may utilise the anterolateral or direct anterior approach judicially. Release of the adductors may be performed in conjunction with primary total hip arthroplasty to help with post-operative range of motion and to decrease risk of instability. In a standard bearing, the selected head size should be the largest that can be utilised for the particular cup size. Rigorous testing of intra-operative impingement, component rotation, and instability is required. If instability cannot be adequately addressed by a standard bearing, the next option is a dual mobility bearing. Multiple studies have shown improved stability with the use of these bearings, but they are also at risk for instability, intraprosthetic dislocation, and fretting and corrosion of the modular connections. Another option is a constrained liner. However, this results in reduced range of motion, and an increased risk for mechanical complications of the construct. The use of a constrained liner in a primary situation should be limited to the most severe instability cases, and the patient should be counseled with the associated risks. If total hip arthroplasty results in repeated instability, revision surgery or Girdlestone arthroplasty may be considered

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 or ceramic head is snap-fit into the large polyethylene. In some European centers, these components are routinely used for primary total hip arthroplasty. However, their greatest utility will be to prevent and manage recurrent dislocation in the setting of revision total hip arthroplasty. Several retrospective series have shown satisfactory results for this indication at medium-term follow-up times. The author has used dual mobility components on two occasions to salvage a failed constrained liner. At least one center reports that dual mobility outperforms 40mm femoral heads in revision arthroplasty. Modular dual mobility components, with screw fixation, are the author's first choice for the treatment of recurrent dislocation, revision of failed metal-metal resurfacing, total hips, unipolar arthroplasties, and salvage of failed constrained liners. There are concerns of elevated metal levels with one design, and acute early intra-prosthetic dissociation following attempted closed reduction. Total hip surgeons no longer cement Charnley acetabular components, use conventional polyethylene, autologous blood donation, or a drain; now constrained components join these obsolete techniques! In 2017, a dual mobility component, rather than a constrained liner, is the preferred solution in revision surgery to prevent and manage recurrent dislocation