A total hip replacement (THR) patient's spinopelvic mobility might predispose them to an increased risk of impingement, instability and edge-loading. This risk can be minimised by considering their preoperative movement during planning of component alignment. However, the question of whether the preoperative, arthritic motion is representative of the postoperative mobility has been raised. We aimed to determine the change in functional pelvic tilt in a series of THR patients at one-year.

Four-hundred and eleven patients had their pelvic tilt and lumbar lordotic angle (LLA) measured in the standing and flexed-seated (position when patients initiate rising from a seat) positions as part of routine planning for THR. All measurements were performed on lateral radiographs. At 12-months postoperatively, the same two lateral images were taken and pelvic tilt measured. Pearson correlation was used to investigate the linear relationship between pre-and post-op pelvic tilt. Furthermore, a predictive model of post-op pelvic tilt was developed using machine learning algorithms. The model incorporating four preoperative inputs – standing pelvic tilt, seated pelvic tilt, standing LLA and seated LLA.

In the standing position, there was a mean 2° posterior rotation after THR, with a maximum posterior change of 13°. The Pearson correlation coefficient between pre-and post-op standing pelvic tilt was 0.84. This prediction of post-op standing tilt improved to 0.91 when the three further inputs were incorporated to the predictive model.

In the flexed-seated position, there was a mean 7° anterior rotation after THR, with a maximum anterior change of 45°. The Pearson correlation coefficient between pre-and post-op seated pelvic tilt was 0.54. This prediction of post-op seated tilt improved to 0.71 when the three further inputs were incorporated to the predictive model.

The best predictor of post-operative spinopelvic mobility, is the patients pre-operative spinopelvic mobility, and this should routinely be measured when planning THR

The predictive model will continue to improve in accuracy as more data and more variables (contralateral hip pathology, pelvic incidence, age and gender) are incorporated into the model.

Patients may present with concurrent symptomatic hip and spine problems, with surgical treatment indicated for both. Controversy exists over which procedure, total hip arthroplasty (THA) or lumbar spine procedure, should be performed first.

Clinical scenarios were devised for 5 fictional patients with both symptomatic hip and lumbar spine disorders for which surgical treatment was indicated. An email with survey link was sent to 110 clinical members of the NA Hip Society requesting responses to: which procedure should be performed first; the rationale for the decision with comments, and the type of THA prosthesis if “THA first” was chosen. The clinical scenarios were painful hip osteoarthritis and (1) lumbar spinal stenosis with neurologic claudication; (2) lumbar degenerative spondylolisthesis with leg pain; (3) lumbar disc herniation with leg weakness; (4) lumbar scoliosis with back pain; and (5) thoracolumbar disc herniation with myelopathy. Surgeon choices were compared among scenarios using chi-square analysis and comments analyzed using text mining.

Complete responses were received from 51 members (46%), with a mean of 30.8 (± 10.4) years of practice experience. The percentages of surgeons recommending “THA first” were 59% for scenario 1; 73% for scenario 2; 47% for scenario 3; 47% for scenario 4; and 10% for scenario 5 (χ²=44.5, p<0.001). Surgeons were significantly more likely to choose “THA first” despite radicular leg pain (scenario 2), and less likely to choose “THA first” with the presence of myelopathy (scenario 5). The choice of “THA first” in scenarios 1, 3, and 4 were more equivocal, dependent on surgeon impression of clinical severity. For type of THA prosthesis, dual mobility component was chosen by: 12% in scenario 1; 16% in scenario 2; 8% in scenario 3; 24% in scenario 4; and 10% in scenario 5. Surgeons were more likely to choose dual mobility in scenario 4, but with the numbers available this was not statistically significant (χ²=6.6, p=0.16). The analysis of comments suggested the importance of injection of the joint for decision making, the merit of predictable outcome with THA first, the concern of THA position with spinal deformity, and the urgency of myelopathy.

With the presence of concurrent hip and spine problems, the question of “THA or lumbar surgery first” remains controversial even for a group of experienced hip surgeons. Outcome studies of these patients are necessary for appropriate decision making.

To assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular dual mobility acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design.

This was a prospective study of patients  65 years of age, with a BMI  35 kg/m², and UCLA activity score > 6 who received a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. All patients had a minimum of 2-year clinical follow-up.

Patient reported outcome measures, whole blood metal ion levels (ug/L), and periprosthetic femur BMD were measured at baseline and at 1- and 2-years postoperatively.

43 patients (30 male, 13 female; mean age 52.6 ± 6.5 years) were enrolled. Harris Hip Scores improved from 54.1 ± 20.5 to 91.2 ± 10.8 at 2 years postoperatively (p<0.001). All patients had radiographically well-fixed components, no patients have sustained an instability event, and no patients have required a return to the operating room or revision procedure.

Mean cobalt levels increased from 0.065 ± 0.03 ug/L preoperatively to 0.30 ± 0.51 at 1-year postoperatively (p=0.01), but decreased at 2 years postoperatively to 0.16 ± 0.23 (p=0.2) (Table 1). Four patients (9.3%) had a cobalt level outside the reference range (0.03 to 0.29ug/L) at 2 years postoperatively with values from 0.32 to 0.94. None were symptomatic

The mean femoral BMD ratio was maintained in Gruen zones 2 thru 7 at both 1- and 2-years postoperatively using this stem design (Table 2). At 2 years postoperatively, BMD in the medial calcar was 101.5% of the baseline value.

Use of a modular dual mobility prosthesis and cementless, tapered femoral stem has shown encouraging results in young, active patients undergoing primary THA. Elevation in mean cobalt levels and the presence of four patients outside the reference range at 2 years postoperatively demonstrates the necessity of continued surveillance in this cohort.

For any figures or tables, please contact authors directly: barrackr@wustl.edu

We aimed to demonstrate the clinical safety of a novel anatomic cementless ceramic hip resurfacing device. Concerns around the safety of metal on metal arthroplasty have made resurfacing less attractive, while long term function continues to make the concept appealing. Biolox Delta ceramic is now used in more than 50% of all hip arthroplasties, suggesting that it's safety profile is acceptable. We wondered if a combination of these concepts might work?

The preclinical testing of anatomic hip resurfacing device developed by our group was presented last year. A twenty patient safety study was designed. Patients had to be between the ages of 18 and 70. The initial size range was restricted to femoral heads between 46 and 54, representing the common sizes of hip resurfacing. The primary outcomes were clinical safety, PROMs and radiological control. Secondary outcomes include CTRSA and metal ion levels.

20 patients were recruited, aged 30–69. 7 were women and 13 were men. There were no operative adverse events in their operations undertaken between September 2017 and February 2018. One patient had a short episode of atrial fibrillation on the second postoperative day, and no other complications. At three months the median oxford hip score had risen from 27 (range 14–38) to 46 (31–48). Cobalt and chromium levels were almost undetectable at 3 months. Fixation appeared satisfactory in all patients, with no migration detected in either component. CTRSA is in process.

The initial safety of a novel cementless ceramic resurfacing device is demonstrated by this data. The 10 year, 250 case efficacy study will continue in 5 other European centres.

Robotic assisted surgery aims to reduce surgical errors in implant positioning and better restore native hip biomechanics compared to conventional techniques for total hip arthroplasty (THA). The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual THA versus robotic-arm assisted THA. Secondary objectives were to determine differences between these treatment techniques for THA in achieving the planned combined offset, cup inclination, cup version, and leg-length correction.

This prospective cohort study included 50 patients undergoing conventional manual THA and 25 patients receiving robotic-arm assisted THA. All operative procedures were undertaken by a single surgeon using the minimally-invasive posterior approach. Two independent blinded observers recoded all radiological outcomes of interest using plain radiographs. Patients in both treatment groups were well-matched for age, gender, body mass index, laterality of surgery, and ASA scores.

Interclass correlation coefficient was 0.92 (95% CI: 0.84 – 0.95) for intra-observer agreement and 0.88 (95% CI: 0.82–0.94) for inter-observer agreement in all study outcomes. Robotic THA was associated with improved accuracy in restoring the native horizontal (p<0.001) and vertical (p<0.001) centres of rotation, and improved preservation of the patient's native combined offset (P<0.001) compared to conventional THA. Robotic THA improved accuracy in positioning of the acetabular cup within the combined safe zones of inclination and anteversion described by Lewinnek et al (p=0.02) and Callanan et al (p=0.01) compared to conventional THA (figures 1–2). There was no difference between the two treatment groups in achieving the planned leg-length correction (p=0.10).

Robotic-arm assisted THA was associated with improved accuracy in restoring the native centre of rotation, better preservation of the combined offset, and more precise acetabular cup positioning within the safe zones of inclination and anteversion compared to conventional manual THA.

Robotic-arm assisted THA enables improved preservation of native hip biomechanics compared to conventional manual THA.

For any figures or tables, please contact authors directly: fsh@fareshaddad.net

Obesity has previously been demonstrated to be an independent risk factor for increased complications following total hip (THA) and total knee arthroplasty (TKA). The purpose of this study was to compare the effects of obesity and BMI to determine whether the magnitude of the effect was similar for both procedures.

We queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to identify patients who underwent primary THA or TKA between 2010 and 2014. Patients were stratified by procedure and classified as non-obese, obese, or morbidly obese according to BMI. Thirty-day rates of wound complications, deep infection, total complications, and reoperation were compared using univariate and multivariate logistic regression analyses.

We identified 64,648 patients who underwent THA and 97,137 patients who underwent TKA. Obese THA patients had significantly higher rates of wound complications (1.53% vs 0.96%), deep infection (0.31% vs 0.17%), reoperation rate (2.11% vs 1.02%), and total complications (5.22% vs. 4.63%) compared to TKA patients. Morbidly obese patients undergoing THA were also found to have significantly higher rates of wound complications (3.25% vs 1.52%), deep infection (0.84% vs 0.23%), reoperation rate (3.65% vs 1.60%), and total complications (7.36% vs. 5.57%). Multivariate regression analysis identified increasingly higher odds of each outcome measure as BMI increased.

This study demonstrates the impact of obesity on postoperative complications is more profound for THA than TKA. This emphasizes the importance of considering patient comorbidities in the context of the specific procedure (hips and knees should be analyzed independently) when assessing risks of surgery.

The purpose of this randomized controlled trial is to evaluate the efficacy of using dilute betadine versus sterile saline lavage in aseptic revision total knee (TKA) and hip (THA) arthroplasty to prevent acute postoperative deep periprosthetic joint infection (PJI).

Of the 450 patients that were randomized, 5 did not have 90-day follow-up, 9 did not receive the correct treatment, and 4 were excluded for intraoperative findings consistent with PJI. 221 Patients (144 knees and 77 hips) received saline lavage only and 211 (136 knees and 75 hips) received a three-minute dilute betadine lavage (0.35%) prior to wound closure. Patients were observed for the incidence of acute postoperative deep PJI within 90 days of surgery. Statistical analysis was performed using t-tests or Fisher's exact test where appropriate. Power analysis determined that 285 patients per group are needed to detect a reduction in the rate of PJI from 5% to 1% (alpha=0.05, beta=0.20).

There were seven PJIs in the saline group and one in the betadine lavage group (3.2% vs. 0.5%, p=0.068). There were no significant differences in any baseline demographics between groups suggesting appropriate randomization.

Although we believe the observed difference between treatments is clinically relevant, it was not statistically significant with the sample size enrolled thus far and enrollment is ongoing. Nonetheless, we believe that these data suggests that dilute betadine lavage is a simple method to reduce the rate of acute postoperative PJI in patients undergoing aseptic revision procedures.

The principle function of the “short external rotator” muscle group is primarily as an abductor and extensor of the flexed hip and is better referred to as the “Quadriceps Coxa” (QC). The QC has a profound influenced on weight bearing rising and propulsive motions. The SPAIRE technique preserves Obturator Internus (OI) and Piriformis (P) resulting in improved stability of the hip and potentially improved recovery and function in patients undergoing hip arthroplasty.

Short term outcomes of the first 42 consecutive SPAIRE cases are compared with 86 consecutive cases using the traditional posterior approach that immediately preceded introduction of the technique. The purpose was to document the learning curve and confirm the safety of introducing SPAIRE into routine clinical practice.

The two groups were comparable and there was no statistically significant difference in length of stay, blood loss, intra-or post-operative complications nor radiological measurements relating to the femoral or acetabular components. Statistically significant differences were found for component usage (more uncemented acetabula for SPAIRE), length of operation (8 mins longer with SPAIRE); patient satisfaction was higher at 6 weeks and measured leg length discrepancy less in the SPAIRE group.

SPAIRE has been used routinely for all routine arthroplasties for over two years. RCTs are ongoing to document the effect of SPAIRE on recovery, long term function and activity level. If the potential benefits are confirmed SPAIRE may become the default technique for hip arthroplasty operations through a posterior approach for elective and hip fracture cases.

Despite the earlier work on the bone cement interface in successful Charnley stems lasting 20 years, there is still controversy explaining success and failure of cemented stems. Is it possible to analyse cemented stems histo-pathologically over the whole length of the prosthesis, to show where loosening might start or where the osseous structure resists components' failure?

The purpose of this analysis was to develop histo-pathological procedures, to provide information about bony integration or fibrous encapsulation.

This study took place over the past 12 years. Fourteen femoral stems from autopsies, 2 to 26 years post implant - Charnley, Exeter and Muller prosthesis. All clinically and radiologically sound, patients died for reasons unrelated to the implant.

Sections were cut in a complete sequence and analysed using a new microscope, the HIIFL microscope, ZOW Munich; thin sections were processed using embedding in epoxy-resin and bloc-staining in alkaline fuchsine. The sequence of sections was performed using a wet-grinding cutting process, ZOW Munich.

The analysis resulted in a very simple and unique experience. Independent of how long the implant was in place, there was no or nearly no radiolucent line in the X-ray. In defined compartments, surprisingly, cancellous bone was preserved and in many cases stiffened by bone cement. Bone to cement contacts without interposition of fibrous tissue. The findings might influence the operating techniques in the future. The results were fully coincident to findings in animal experiments of earlier work, including the secondary medullary cavity.

Stress shielding has been a well-recognised problem with uncemented femoral components resulting in proximal bone loss and dysfunction, but less attention has been paid to the preservation of acetabular bone stock. Uncemented acetabular components often demonstrate reduced bone density on plain radiographs in the mid-portion of the cup (zone 2), which may be due to the rigidity of the outer shell. This study compares the change in bone density around three different cups with varying moduli of elasticity at a minimum of 2 years. Our hypothesis was that less rigid cups would be associated with improved bone density and less stress shielding.

This prospective randomised controlled trial compared the bone mineral content (BMC) adjacent to three different cups with marked differences in stiffness. Cup A was an all titanium shell, cup B was a titanium coated all polyethylene implant and cup C was a tantalum backed shell. All articulations used a 32mm ceramic femoral head. Cup B used polyethylene modified by treatment with vitamin E whereas cups A and C used a liner made of irradiated cross linked polyethylene.

Five regions of interest (ROI) were established adjacent to the cup, regions 2, 3 and 4 where similar to the DeLee and Charnley regions 1, 2 and 3. Bone density was measured using IDXA preoperatively, postoperatively, 6 months, 1 and 2 years and compared for each ROI and implant.

Precision measurements showed significant reliability. All areas showed a reduction in BMC following insertion of the acetabular cup. Bone loss was less in ROI 1 and 4 in the area of rim fit for all cups and the maximal bone loss was seen in ROI 2 and 3 at the dome of the cup. The more elastic cup (Cup B) produced the least bone loss in this area (p<0.05). Cup C produced the largest bone loss at ROI 2 (40%) which continued increasing at 2 years.

Cup stiffness is related to bone loss adjacent to the acetabulum, presumably due to a similar process of stress shielding as seen in the femur. All cups produced similar changes at the periphery of the cup but the more elastic cup retained bone density beneath the cup which continued past 2 years. This improvement in bone quality is likely to be associated with better acetabular bone stock into the future and more reliable long term cup fixation.

The hip joint capsular ligaments (CL) passively restrain extreme range of motion (ROM) by wrapping around the native femoral head, and protect against impingement, edge loading wear and dislocation. This study compared how ligament function was affected by device (hip resurfacing arthroplasty, HRA; dual mobility total hip arthroplasty, DM-THA; and conventional THA, C-THA), with and without CL repair. It was hypothesized that ligament function would only be preserved when native anatomy was preserved: with restoration of head-size (HRA or DM-THA) and repair.

Eight normal male cadaveric hips were skeletonised, retaining the hip capsule. CL function was quantified by measuring ROM by internally (IR) and externally rotating (ER) the hip in six functional positions, ranging from full extension with abduction to full flexion with adduction (squatting). Native ROM was compared to ROM after posterior capsulotomy and HRA, and C-THA and DM-THA, before and after surgical CL repair.

ROM increased most following C-THA (max 62°), then DM-THA (max 40°), then HRA (max 19°), indicating later engagement of the capsule and reduced biomechanical function with smaller head-size. Dislocations also occurred in squatting after C-THA and DM-THA. CL-repair following HRA restored ROM to the native hip (max 8°). CL-repair following DM-THA reduced ROM hypermobility in flexed positions only and prevented dislocation (max 36°). CL-repair following C-THA did not reduce ROM or prevent dislocation.

When HRA was combined with repair, native anatomy was preserved and ligament function was restored. For DM-THA with repair, ligament function depended on the movement of the mobile bearing resulting in near-native function in some positions, but increased ROM when ligaments were unable to wrap around the head/neck. Following C-THA, the reduced head-size resulted in inferior capsular mechanics in all positions as the ligaments remained slack, irrespective of repair.

Choosing devices with anatomic head-sizes (resurfacing or dual-mobility) and repairing the capsular ligaments may protect against instability in the early postoperative period.

Subjective outcomes used in THA show outstanding improvements in patient-reported outcomes. However, recent evidence suggests that there may be a disconnect between patient-reported and objectively measured function. The aim of this study was to investigate if physical activity and sleep patterns change from pre- to six months post primary THA.

54 patients scheduled for THA were recruited. Patients were given a wrist-worn accelerometer (GeneActiv, UK) to wear continuously for one week pre-operatively and six weeks, three months and six months post-operatively. The device was also fitted to the patient immediately following surgery to capture data for the first two post-operative weeks. The following parameters were calculated: (1) sleep efficiency; (2) the amount of time (and length of each bout and fragmentation of the activity) spent in sedentary activity; and (3) time spent in light, moderate and vigorous physical activity.

Sedentary activities showed no change in the number, duration or fragmentation (p= 0.382, 0.288, 0.382, respectively). Patients were sedentary for 5–6 bouts/day with each bout lasting 50–76 minutes/day. A significant main effect was identified for time spent in light intensity activities (p=0.049). Prior to surgery, patients spent 201 minutes/day in light intensity activity. This decreased significantly to 133 minutes/day (p=0.025) in the first two postoperative weeks before returning close to pre-operative levels (192 minutes/day) at six weeks (p=0.025). No further changes were observed in light intensity activities. A significant main effect was identified for time spent in moderate intensity activities (p=0.003). Prior to surgery, patients spent 45 minutes/day in moderate intensity activities. This dropped to 18 minutes/day in the first two postoperative weeks (p=0.190). By three months this had increased to 66 minutes/day (p=0.049). No further changes were seen. There were no significant differences in time spent in vigorous intensity activities (p=0.244). Patients spent <1minute/day in vigorous intensity activities.

Sleep efficiency did not change significantly from pre- (82%) to six months post-operative (75%) (p=0.067) − 85% is typically considered good sleep efficiency. Patients discharged to a regional hospital had significantly poorer sleep efficiency than those discharged home (mean difference=14%, p=<0.001) or to a rehabilitation centre (mean difference=15%, p=0.001).

This patient cohort didn't demonstrate an overall improvement in objectively measured physical activity patterns from pre- to six months post-operative. Sleep efficiency, did not improve and remained sub-optimal.

The Oxford hip score (OHS) at 6 months and five years of less than 27 has previously been reported as having a 5.2% chance of requiring revision of their total hip arthroplasty (THA) within 2 years. We determined whether the OHS obtained at 10 years after surgery would be a suitable screening tool in lieu of clinic visits to detect patients requiring closer monitoring.

We reviewed data from the NZ Joint Registry between January 1999 and December 2016. OHS at 10 years was available for 5,165 non-revised THA patients. Patients were separated into four categories based on their OHS: 3,483 (67%) scored 42–48, 1,023 (20%) scored 34–41, 373 (7%) scored 27–33, and 286 (5%) scored 0–26.

For patients with a 6-month OHS, revision risk within 2 years was 1.3% in the 42–48 group, 2.5% in the 34–41 group, 4.6% in the 27–33 group, and 10.2 % in the 0–27 group. If only patients with a grading of 33 or less were offered clinical follow-up, 659/5165 patients (12.7%) would require evaluation and of these, 46/659 (7%) could be expected to require revision within two years. Of those patients with an OHS > 34 not evaluated, only a small number, 72/4506 (1.6%), might require a revision.

The OHS at 10 years of patients with a THA who have a grading less than 27 is a much stronger predictor of revision than OHS at 6 months or 5 years. Use of the 10 year OHS as a screening tool for THA requires evaluation of only one in eight patients, with the chance of missing 1 in 63 patients not followed up who might require a revision.

Evaluation of the anatomical features, details of surgical technique and results of the THA in patients with CDH (type C1 and C2 by G. Hartofilakidis).

From 2001 to 2016 years one surgical team performed 683 THA in patients with CDH. We retrospectively studied 561 total hip arthroplasties in 349 patients, follow-up rate was 82.1%, from 12 to 188 months (mean 69.4). The results were evaluated by clinical examination, X-rays analysis, Harris Hip Score.

Unilateral high hip dislocation was observed in 175 patients (31.2%), in these cases often have underdeveloped half of the pelvis on the side of the dislocation. Type C1 was observed in 326 cases and type C2 – in 235 cases. Type C1 in comparison with C2 has less leg length discrepancy, developed shape of proximal femur, presence of supraacetabular osteophyte. The mean displacement of femoral head was 47.6 mm (from 29 to 55) for C1 and 63.4 mm (from 41 to 78) for C2. Average offset in C1 was 50.1 mm (37–63) and in C2 − 44.3 mm (34–52).

Shortening osteotomy by T. Paavilainen performed in 165 cases (50.6%) with C1 dysplasia and in 235 cases (100%) with C2. The features of surgical technique were small size of the cups with obligatory additional screw fixation of the cup and small offset of the stems. The cup was positioned into the true acetabulum in 99.1% cases of C2 type, for C1 – only 69.0%). The cups size 44 mm were used in 97.3% cases for type C2 and in 78.6% cases for type C1. For shortening osteotomy in 76.3% cases Wagner Cone stems were used.

Early complications included 9 dislocations (1.6%), 8 femoral nerve neuropathies (1.4%) and 3 infections (0.5%). There is no sciatic nerve palsy. Late complications included dislocation in two hips (1.1%), nonunion of the greater trochanter (8.4%), aseptic loosening of the femoral component − 2 (0.8 %), aseptic loosening of the cup − 11 (1.6%). Average Harris Hip score improved from 39.5 to 83.6 with unsignificant diffence between types C1 and C2 (from 37.3 to 81.4 and from 40.4 to 85.1 consequently). Revision rate was 2.1% for type C1 and 5.5% for type C2.

Hip replacement surgery in patients with high hip dislocation is very challenging. Type C2 dysplasia has only one surgical option with good long-term results – placement of the cup into the true acetabulum and shortening osteotomy. Its advantages include leg length alignment and decreased risk of sciatic nerve injury. Type C1 dysplasia presents more heterogenic group of patients and allows to use several surgical options – different placement of the cup and surgical approach without shortening osteotomy. Functional results in patients with type C1 are a little bit worse in comparison with type C2, but C1 had less risk of complications. The main problem of shortening osteotomy by Paavilainen is delayed union and non-union of great trochanter.

The Swedish Hip Arthroplasty Register started in 1979 and celebrates its 40^th anniversary in 2019. The Swedish Hip Arthroplasty Register is not primarily a device register or research database; we strive to provide an overall assessment of the care provided with a multidimensional approach, and to disseminate knowledge on best practices in our network of participating hospitals. Since the inception of the register, there has been a marked change in trends and outcomes.

The completeness of registrations has been 97–99% for primary THA, 93–95% for revisions, and 95–98% for HA over the last 10 years. The register contains 371,125 primary THAs, 55,893 HAs, 83,233 reoperations, and 408,110 PROM responses registered in 352,585 unique patients. All outcome measures have improved over time; primary THA has 0.71% 90-day mortality, 94.3% 10-year implant survival, and 2.2% 2-year reoperation rate. At 1-year follow up, 91% of the patients report a clinically significant pain reduction, 76% report a substantial improvement in health-related quality of life, and 89% are satisfied with the result of the operation.

Moving forward, we are developing enhanced online applications for surgeons, patients and the implant industry to access real-time information. This work involves constructing a shared decision-making tool that helps clinicians assessing the future benefits and risks of THA by offering individualized outcome predictions. Further steps forward include randomized clinical trials and nested studies through the registry's platform. The trends and changes in Swedish arthroplasty practice have largely been promoted and facilitated by the register over the last 40 years.

The purpose of this study is to compare 90-day costs and outcomes for primary total hip arthroplasty (THA) patients between a non-obese (BMI 18.5–24.9) versus overweight (25–29.9), obese (30–34.9), severely-obese (35–39.9), morbidly-obese (40–44.9), and super-obese (45+) cohorts.

We conducted a retrospective review of a prospective institutional database of primary THA patients from 2006–2013, including patients with a minimum of three-year follow-up. Thirty-three super-obese patients were identified, and the other five cohorts were randomly selected in a 2:1 ratio (total n = 363). Demographics, 90-day outcomes (costs, reoperations, and readmissions), and outcomes after three years (revisions and change scores for SF12, HHS, and WOMAC) were collected. Costs were determined using unit costs from our institutional administrative data for all in-hospital resource utilization. Comparisons between the non-obese and other groups were made with Kruskal-Wallis tests for non-normal data and chi-square and Fisher's exact test for categorical data.

The 90-day costs in the morbidly-obese ($13,134 ± 7,250 mean ± standard deviation, p <0.01) and super-obese ($15,604 ± 6,783, p <0.01) cohorts were statistically significantly greater than the non-obese cohorts ($10,315 ± 1,848). Only the super-obese cohort had statistically greater 90-day reoperation and readmission rates than the non-obese cohort (18.2% vs 0%, p <0.01 and 21.2% vs 4.5%, p=0.02, respectively). In addition, reoperations and septic revisions after 3 years were greater in the super-obese cohort compared to the non-obese cohort 21.2% vs 3.0% (p = 0.01), and 18.2% vs 1.5% (p= 0.01), respectively. There were no other statistical differences between the other cohorts with the non-obese cohort at 90-days or after 3 years. Improvements in SF12, HHS, and WOMAC were comparable in all cohorts.

The 90-day costs of a primary total hip arthroplasty for morbidly-obese (BMI 40–44.9) and super-obese (BMI>45) are significantly greater than for non-obese patients, yet these patients have comparable improvements in outcome scores. Health care policies, when based purely on the economic impact of health care delivery, may place morbidly-obese and super-obese patients at risk of losing arthroplasty care, thereby denying them access to the comparable quality of life improvements.

Total hip arthroplasty (THA) continues moving to the outpatient arena, and may be feasible for some conversion and revision scenarios. Controversy surrounds appropriate patient selection. The purpose of this study is to report complications associated with outpatient revision and conversion THA, and to determine if comorbidities are associated with complications or overnight stay.

From June 2013 through March 2018, 43 patients (44 hips) underwent conversion (n=12) or revision (n=32) THA at a free-standing ambulatory surgery center. Mean patient age was 58.4 years, and 52% of patients were male. Conversion procedures were for failed resurfacing in two, failed hemiarthroplasty in one, and failed fracture fixation with retained hardware in 9. Revision procedures involved head only in one, head and liner in 20, cup and head in 7, stem only in 2, and stem and liner in 2.

Forty-four (93%) were discharged same day without incident, none required transfer to acute facility, and 3 required overnight stay with 2 of these for convenience and only one for a medical reason, urinary retention. Three patients with early superficial infection were successfully treated with oral antibiotics. There were no major complications, readmissions, or subsequent surgeries within 90 days. One or more major comorbidities were present in 17 patients (39%) including 1 valvular disease, 8 arrhythmia, 2 thromboembolism history, 3 obstructive sleep apnea, 6 chronic obstructive pulmonary disease, 2 asthma, 4 frequent urination, and 1 renal disease. The single patient who stayed overnight for a medical reason had no major medical comorbidities.

Outpatient arthroplasty, including revision THA in some scenarios, is safe for many patients. Presence of medical comorbidities was not associated with risk of complications. The paradigm change of patient education, medical optimization, and a multimodal program to mitigate risk of blood loss and reduce need for narcotics facilitates performing arthroplasty safely in an outpatient setting.

Hip and knee revisions continue to increase in number and complexity. With an understanding that revisions have a high re-revision rate, the importance of correct decisions made at the index procedure, is paramount for patients and surrounding health care economy.

Since January 2015, East Midlands Specialist Orthopaedic Network, (set up on a ‘hub-and-spoke’ model), has allowed all revisions performed within our region, (5 hospitals with a 4 million population), to be discussed at a weekly ‘web’ conference. Integrated radiology allows clinical information to be reviewed remotely at each hospital. Chaired by specialist revision surgeons, with other surgeons, a microbiologist and radiology, vascular, plastics opinions available as required, a formal management plan is ‘signed off’ by the chair and returned to referring institution. We present prospective data of Network activities.

To January 2018, 1007 cases have been referred by 18 consultants from 5 hospitals. A change in proposed plan was seen in 48% cases. (40% involved technique and exposure advice; 18% involved surgical inventory; 22% further investigation; 11% microbiological input; 9% other miscellaneous advice) Few (5%) patients were transferred directly. We also identified 20% increase in outpatient referrals to the ‘hub’.

The network is an excellent tool for discussing complex cases, supporting surgeons in smaller units. A significant number of alterations in plan are made with a few patients transferred directly. We feel the network can only enhance care and are working now to identify exactly how it has affected clinical outcomes. We encourage others to adopt this approach.

A longitudinal study was done assessing the latest radiographs available in a series of collarless Corail uncemented stems which have reported survival rates of 95% at 20 years. Parameters scored included the degree of “Ghosting” or delamination, the Gruen, the stem fit in the femoral canal and the degree of calcar resorption. Patient and implant demographics were noted.

At 3 years the loosening rate was 23% reaching 64% at 6 years after the index procedure. It was present in all age groups, with a peak in the 24 to 49 year age group. Males and females had the same occurrence. When it was present this was always in zone 1. It was present in 6% of patients in zone 7, but then always associated with zone 1 changes. High and standard off-set stems had the same loosening rates. The looser fit of the stem the higher the incidence of loosening. There was no correlation to the type of bearing surface or the degree of calcar resorption. Those patients with a BMI of 25 – 35 had lower loosening rates compared to those with higher or lower BMI's.

We postulate that cancellous bone on-growth onto the hydroxyapatite coating associated with loading flexural micro-motion leads to hydroxyapatite being pulled off the smooth stem substrate in zone 1. Progressive delamination of the hydroxyapatite then occurs. The triple-tapered design though imparts continued stability.

We report high loosening rates in the Corail stem and suggest a mechanism for its development.

Reconstruction of massive acetabular bone defects in primary and revision THA is challenging for reconstructive joint surgeons. The use of porous metal augments is one of the options. The advantages of porous metal augments are easy to use, modularity and lack of resorption. We investigated the radiological results of porous metal augments used for massive acetabular bone defects in primary and revision THA.

Forty-one hips in forty patients had porous metal augments between 2011 and 2016. Thirty of the procedures were revision arthroplasties and 11 were primary procedures (Crowe type III in 5 hips, Crowe type IV in 3, septic hip sequalae in 2 and RA in one). Four of the revisions were second-stage reimplantation after infection. The Paprosky classification for revision was 2B in 4 hips, 2C in one, 3A in 3 and 3B in 22. Regenerex augments were used in 39 hips and trabecular metal augments were used in 2. Thirty-six cups were cemented and 5 cups were uncemented.

Mean follow-up was 37.6 months (range, 1–82). Radiographic findings of osteointegration between host bone and the porous metal augments were assessed. The presence or absence of radiolucent lines between cement or cup/host bone and augment/host bone interface was noted.

Two revisions were performed due to infection, one month and 66 months after operation. The other implants were stable without any complications. Osteointegration between host bone and the porous metal augments were recognized in 36 hips. Radiolucent lines between cement/host bone interface, less than 1 mm in width, were visualized in 2 hips.

Porous metal augments are convenient and our short-term results showed excellent radiological results for massive acetabular bone defects in primary and revision THA.

Failed ingrowth and subsequent separation of revision acetabular components from the inferior hemi-pelvis constitutes a primary mode of failure in revision total hip arthroplasty (THA). Few studies have highlighted other techniques than multiple screws and an ischial flange or hook of cages to reinforce the inferior fixation of the acetabular components, nor did any authors report the use of porous metal augments in the ischium and/or pubis to reinforce inferior fixation of the acetabular cup.

The aims of this study were to introduce the concept of inferior extended fixation into the ischium and/or pubis during revision total hip arthroplasty, and to answer the following questions: (1) what are early clinical outcomes using inferior extended fixation and (2) what are the radiographic outcomes of hips revised with inferior extended fixation?

Patients who underwent revision THA utilizing the surgical technique of inferior extended fixation with porous metal augments secured in the ischium and/or pubis in a single institution from 2014 to 2016 were reviewed. Twenty-four patients were initially identified, and 16 patients were included based on the criteria of minimum 18 months clinical and radiographic follow-up.

The median HHS, as well as the SF-12 physical and mental components improved significantly at the latest follow-up (p<0.001). The WOMAC global score decreased significantly at the latest follow-up (p<0.001). All constructs were considered to have obtained bone ingrowth fixation.

Early follow-up of patients reconstructed with porous metal augments using the inferior extended fixation surgical technique demonstrated satisfactory clinical outcomes, restoration of the center of rotation and adequate biological fixation.

There is still little information on the histological characteristics of the acetabular bone tissue after failure of the primary prosthetic component. The purpose of this study is to characterize the viability and quality of the acetabular bone tissue in patients undergoing acetabular revision for aseptic loosening of uncemented components.

19 patients were enrolled: 14 hip revisions and 5 primary total hip arthroplasty. Samples collecting: three acetabular bone biopsy of patients were collected at the time of surgery with a 8G diameter needle after reaming. Histological evaluation: all samples, after removing the mineral component, were cut longitudinally with a thickness section of 5μm and colored with hematoxylin-eosin dichromic dye. Histological evaluation was done by optical microscopy with 40× magnification. Five bone quality classes were developed by evaluating percentage of aseptic necrosis, percentage of active osteoblasts, presence of osteopenia, presence of osteoclasts, absence of intramedullary hematopoietic component. Histological evaluation: the bone quality of cases was significantly poorer than the controls. The differences found were statistically significant between the two groups for percentage of necrosis (p=0.0033), percentage of active osteoblasts (p=0.0071) and presence of osteopenia (p=0.037).

Overall bone quality was significantly worse in the study group due reduced viability, overturn of lamellar structures, reduced amount of intramedullary hematopoietic component in respect to the controls; this could result in poor ability of the host bone to interact with the implanted components.

Highly porous tantalum cups have been used in complex acetabular revisions for nearly 20 years but reports of long term results are limited. This study was designed to report ten year results of revision using a single porous tantalum cup design with special attention to re-operation for any reason, all-cause revision, and revision for aseptic loosening.

Retrospective review of all revision THA cases performed from 1999–2006 using a highly porous tantalum acetabular component design with multiple screw holes and a cemented polyethylene liner (Zimmer Biomet, Warsaw, IN). Our institutional medical record and total joint registry were used to assess follow-up and xrays were reviewed. The Paprosky classification system was used to rate acetabular bone loss. Radiographic loosening was defined as new/progressive radiolucencies in all 3 acetabular zones, or cup migration (>2mm). Kaplan-Meier survivorship was used to assess survivorship free of cup revision/removal for any reason, and free of revision for aseptic loosening.

Between 1999 and 2006 this tantalum cup was used in 916 revisions. Mean age: 66 (±6), BMI: 29 (±6), and male: 42%. Indications for revision: aseptic loosening 346 (38%), osteolysis 240 (26%), and infected arthroplasty 168 (18%). Large (3A or 3B) bone defects were present in 260, and pelvic discontinuity in 61. Reoperation for any reason: 133 (15%), but 84 of 133 cases did not require cup revision for instability (38) or femoral failure (24). Tantalum cup removal/revision was required in 49 (5.3%) for deep infection (39) and recurrent dislocation (6), and aseptic loosening (4). 10 year survivorship free of cup revision for any reason: 95% and for aseptic loosening: 99%. Radiographic review (mean 10 years): suspicious for aseptic loosening in another 4 cups.

A highly porous tantalum acetabular component with multiple screws and a cemented polyethylene insert provided durable long term fixation for an array of acetabular revision problems. Long term aseptic loosening was very rare (<1%) and cup removal was mainly related to deep infection, and rarely dislocation.

Assess union rate, complications, and outcomes of large series of contemporary extended trochanteric osteotomies (ETOs) performed during revision THAs.

From 2003 to 2013, 612 ETOs were performed during revision THAs using 2 techniques. 367 were Paprosky type and 245 were Wagner type. Indications were aseptic loosening (65%), periprosthetic joint infection (18%), periprosthetic fracture (6%), femoral implant fracture (5%), and other (6%). Mean age 69 years, 58% male. Median follow-up 5 years (range, 2.1 to 13 years).

Mean Harris Hip Scores increased from 57 preoperatively to 77 at latest follow-up (p=0.0001). Radiographic union of the extended osteotomy occurred in 98%. There were 9 ETO nonunions. Mean time to union of the distal transverse osteotomy was 5.9 months (range, 1 month − 2 years). Mean trochanteric osteotomy fragment migration prior to union was 3 mm (range, 0–29 mm). Over 1 cm of migration occurred in 7.4%. Intraoperative fracture of the ETO diaphyseal fragment occurred in 4%, and postoperative greater trochanter fractures in 8.8%. Other complications: dislocation in 5.7% and infection in 3.4%. Dislocation occurred in 19 of 462 with ETO migration < 1 cm and 4 of 39 with ETO migration ≥1 cm (p=0.08). Ten year survivorship free of revision for aseptic femoral loosening, free of any component removal or revision, and free of reoperation were 97%, 91%, and 82%, respectively.

The union rate after ETO was high and notable trochanteric migration was infrequent. The most common complication was fracture intraoperatively or postoperatively of the osteotomy fragment.

We questioned about bearing surface and infection in two populations of patients who had bilateral THA with different bearings performed in the same hospital by the same surgical team from the year 1981 to the year 2010 (mean followup 15 years; 7 to 35).

1) first population (mean age 32 years): 325 patients (650 hips) with sickle cell disease (SCD) with two different bearing on each side. 116 patients had Metal on PE (MoP) on one side and Ceramic on PE (CoP) on the contralateral; 106 patients had (CoP) and Ceramic on Ceramic (CoC); 103 patients had MoP and CoC. 2) matched control population (same age, same period) of 820 patients without co-morbidities: 354 patients had MoP and CoP; 237 had CoP and CoC; 229 had MoP and CoC.

Among the 2290 hips, 3 early (less than 12 months) unilateral infections (2 in the controls, 1 in the SCD), and 59 late unilateral infections: 23 (1.4%) in 1640 THAs control, versus 36 (5.5%) in the SCD 650 THAs (P < 0.0001) during the observation period of 35 years.

In control group with the Kaplan-Meier analysis, increase infections over time but different (p=0.02) for each bearing surfaces, respectively from 0% at one year to 0.4% revision (2 cases) at most recent follow-up for 466 CoC hips, from 0% to 1.1% (7 cases) for 591 CoP hips, and from 0.3% to 2.4% (14 cases) for 583 MoP hips.

In sickle cell disease group MoP hips had higher risk of infection (26 among 219) when compared with CoP (9 among 222; p=0.002), and CoC (1 among 209 hips; p=0.0004); with increase over time from 1% at one year to 4% with CoP, and from 1% to 11.8% with MoP.

When contralateral hip of same patient is control, PE components are more prone to infection than those involving ceramic-on-ceramic.

Although there is some clinical evidence of ceramic bearings being associated with a lower infection rate after total hip arthroplasty (THA), available data remains controversial since this surface is usually reserved for young, healthy patients. Therefore, we investigated the influence of five commonly-used biomaterials on the adhesion potential of four biofilm-producing bacteria usually detected in infected THAs.

In this in-vitro research, we evaluated the ability of S. aureus, S. epidermidis ATCC 35984, E. coli ATCC 25922 and P. aeruginosa to adhere to the surface of solid biomaterials, including a 28mm cobalt-chromium metal head, a 28mm fourth-generation ceramic head, a 48mm fourth-generation ceramic insert, a 48mm highly-crossed linked polyethylene insert and a 52mm titanium porous-coated acetabular component. After an initial vortex step, a bacterial separation from the surface of each specimen was done until no remaining attached bacteria were observed by digital optical microscope. The colony-forming units were counted to determine the number of viable adherent bacteria and the bacterial density.

We found no differences on global bacterial adhesion between the different surfaces. E. coli presented the least adherence potential among the analysed pathogens (p<0.001). The combination of E. coli and S. epidermidis generated an antagonist effect over the adherence potential of S. epidermidis individually (58±4% vs. 48±5%; p=0.007). The combination of P. aeruginosa and S. aureus presented a trend to an increased adherence of P. aeruginosa independently, suggesting an agonist effect (71% vs. 62%; p=0.07).

In this study, ceramic bearings appeared not to be related to a lower bacterial adhesion than other biomaterials. However, different adhesive potentials among bacteria may play a major role on infection's inception.

Leukocyte esterase (LE) has shown to be an accurate marker of prosthetic joint infections and has been proposed as an alternative to frozen section (FS) for intra-operative diagnosis. In this study, intra-operative determination of LE was compared with FS for the diagnosis of periprosthetic hip infections.

One hundred and nineteen patients undergoing hip revision surgery due to prosthetic joint failure from June 2015 to December 2017 were considered. Joint fluids were collected before the arthrotomy for determination of LE which was performed by using enzymatic colorimetric strips. Four to six samples were stained with hematoxylin eosin for FS and considered suggestive for infection when at least 5 polymorphonuclear leukocytes in 5 fields at high power fields were found.

Sensitivity and specificity of LE were 100% and 93.8 %, respectively. The positive predictive value was 79.3 %, while the negative predictive value was 100%. Time from collection to response was 20.1 ± 4.4 minutes.

Sensitivity and specificity of FS were 83.3 % and 92.1 %, respectively. The positive and negative predictive values were 84.6 % and 97.1%. Time from sample collection response was 27.2 ± 6.9 minutes.

LE showed a higher sensitivity and a slightly lower specificity and the same diagnostic accuracy of intraoperative FS. The faster turnaround time (about 20 minutes from receiving of sample by the laboratory), its ease of use and the low costs make this test a valuable alternative to frozen sections and is going to replace FS in our clinical practice.

The reported success rate after treatment with debridement, antibiotics and implant retention (DAIR) of hip prosthesis infections has been found variable. We evaluated all reoperations performed because of infection and reported to Swedish Hip Arthroplasty Register (SHAR) between 1999 and 2016. The analyses were separated into reoperations performed for the first time and those which had been preceded by at least one previous reoperation performed because of the same reason. The outcome was repeated reoperation performed because of infection.

1,882 were first-time procedures (Group I) and 2,275 had been preceded by at least one reoperation due to infection (Group II). Head and/or liner exchange had been performed in 47% of the cases in group I, and in 22% in Group II. The mean age varied between 70 and 71 years and there was a dominance of males in all groups (52–59%). Compared to all primary THR performed during this period (n=319,813) patients with inflammatory disease, idiopathic femoral head necrosis and sequel after childhood disease were overrepresented for this type of procedure.

Between 1999 and 2016 the number of DAIR procedures increased from 29 to 383 per year corresponding to 21 and 72 % of all reoperations performed due to infection. In first time reoperations the survival was 74.5±3.1% if the head/liner had been exchanged and 46.2±3.2% if only irrigation and synovectomy had been performed. In patients reoperated at least one time previously due to infection the survival rates dropped to 68.6±4.6% and 34.5±2.4%.

Compared to first time reoperation with exchange of femoral and/or liner, synovectomy and irrigation without exchange of any implant part(s) resulted in an almost tripled risk of a second reoperation due to same reason (Hazard Ratio: 2.8, 95% confidence interval: 2.4–3.3). In cases previously reoperated because of infection (Group II) exchange of head/liner and debridement had a 28% increased risk of failure compared to the corresponding first time reoperations (1.28 1.02–1.6). If none of the components were replaced in Group II, the risk ratio for a new failure increased almost 4 times (3.8 3.3–4.4). Presence of a cemented stem increased the risk for further reoperations due to infection (1.14 1.02–1.28), but not presence of a cemented cup (1.06 0.92–1.19). All hazard ratios were adjusted for age, gender, diagnosis and type of fixation.

The comparatively good results observed after exchange of head and liner might indicate that this is necessary to perform a sufficiently radical debridement. This observation could also be biased by a surgeon related factor suggesting that component exchange mainly is performed by surgeons with long experience of revision surgery.

No single test is 100% sensitive and specific for the diagnosis of prosthetic joint infection. Joint aspiration is currently the only preoperative investigation that can establish the identity of the infecting organism and its antibiotic susceptibilities. Frequently when attempting to aspirate a joint a ‘dry tap occurs as fluid cannot be aspirated. In this situation, normal saline may be injected into the joint and then reaspirated to provide fluid for culture.

The aim of this study was to ascertain the diagnostic accuracy of culture of joint aspiratie with or without saline reaspiration in the event of a dry tap.

A retrospective analysis of 580 hip and knee aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre operative aspiration is routine.

Fluid was aspirated in 313 (54%) cases and dry taps in which saline injection reaspiration was performed occurred in 267 (46%) cases. Overall sensitivity and specificity of diagnostic aspiration were 84% (78–89%) and 85% (81–88%) respectively. Sensitivity and specificity of saline injection-reaspiration after dry tap were 87% (79–82%) and 79% (72–84%) compared to 81% (71–88%) and 90% (85–93%) for direct aspiration.

Pre operative joint aspiration and culture is a sensitive and specific test for the confirmation of diagnosis in patients at a moderate to high risk of prosthetic joint infection. Culture of saline injection-reaspiration also provides accurate diagnostic information in the event of a dry tap. Both methods allow susceptibility testing of relevant organisms and are therefore able to guide peri-operative and cement instilled antibiotic therapy.

Culture of pre operative joint aspirates provides sensitive and specific diagnostic information including antimicrobial susceptibility results.

Saline injection-reaspiration is a useful additional technique in those patients in whom fluid cannot be aspirated.

The infection rate after total joint arthroplasty (TJA) has been shown to be 1–2% in multiple series and registry data. Irrigation, debridement, and polyethylene exchange (IDPE) is a common first line treatment in many cases of acute prosthetic joint infection (PJI). The reinfection rate in open IDPE procedures is variable with studies showing reinfection rates of 10–70% depending on various patient and microbial factors. Our pilot study aimed to determine if the bacterial load in infected total joints was sufficiently reduced by IDPE to allow for the use of post-debridement cultures as an independent marker of procedural success.

46 prosthetic joint infections underwent irrigation and debridement using 6L of normal saline and 3L of a normal saline and bacitracin mixture prior to the insertion of a new polyethylene liner. This protocol utilized a single equipment setup with all surgical members donning new gloves prior to polyethylene exchange. Between 3 and 5 intraoperative cultures were obtained both prior to and after debridement as per the surgeon's standard protocol. A two-tailed student's t-test was used to evaluate for any differences in the rate of positive culture between these two groups.

Of all pre- and post-debridement cultures sampled 66.5% and 60.7% of cultures were positive respectively. No significant difference in the rate of positive intraoperative culture was found between pre-debridement and post-debridement groups (p = 0.52). In 32 of 46 (69%) cases there was no difference in the total number of positive cultures despite a thorough debridement.

Our data shows that open debridement of PJI does not provide a sterile environment, and post-debridement cultures should not be used as an independent marker of procedural success. The role of an irrigation and debridement to reduce the bacterial burden and potentiate the clearance of an infection is established but its efficacy is unclear, and the inability to create a post-debridement sterile environment is a concern.

Deep infection after THA is a devastating complication that implies major suffering for the patients and large costs for society. Reports from multiple national and regional registries show increasing incidence of deep infection. Is this a consequence of improved diagnostics, changed virulence of the causative organism, increased co-morbidity of the patients?

An open database will be setup and hosted by an existing, high quality registry. All possible variables including patient demographic, detailed surgical information, bacteria/fungus characteristics, antibiotic treatment, radiographic findings and follow-up for 3 years will be collected. The incoming data will be displayed on a dashboard with continuous analyses and statistics. Any individual surgeon or hospital can report data.

A board with members from the International Hip Society and the International Society of Arthroplasty Registries will supervise the process and facilitate scientific analyses from collected data.

Although single-stage revision has attracted a lot of attention due to less socioeconomic cost, this technique is not widely used throughout the world due to strict indications. In this situation, we report our outcome on single-stage revision combined with selective direct intra-articular antibiotic infusion for chronic infected THA, especially for patients with culture-negative hip, fungal infections and multidrug-resistant organism.

We retrospectively reviewed 131 patients with chronic infected THA between January 2010 and February 2017 who underwent single-stage revision, including soakage of surgical area with 0.5% aqueous betadine, pouring powdered vancomycin or imipenem into the medullary cavity. For patients with culture-negative hip, fungal infections and multidrug-resistant organism, a direct intra-articular infusion of pathogens-sensitive antibiotics via three-branch catheter were performed postoperatively. Recurrence of infection and clinical outcomes were evaluated.

One hundred and fifteen patients were followed-up for an average of 4.5 years (range, 1.2–8 years). Of the 115 patients, 103 patients (89.6%) required no additional surgical or medical treatment for recurrence of infection. A recurrent infection was observed in 4 of the 23 patients (17.4%) with culture-negative infected hip. One of 4 fungal infections was relapse and the success rate in patients with multidrug-resistant organism was 84.2% (16/19). The mean postoperative Harris hip score was 81 points (63 to 92; p < 0.05) at the most recent assessment.

Treatment of chronic infected THA by single-stage revision combined with selective direct intra-articular antibiotic infusion can be fairly effective, even for patients with relative “contraindication” of this approach.

A randomized trial was designed to compare the outcome of ceramic-on-ceramic with ceramic on conventional polyethylene. These patients have been followed for 15 years.

58 hips in 57 patients under 60 years of age were randomized into one of two groups. Patients were blinded to the type of hip they received. Both groups of patients were treated routinely with prophylactic peri-operative antibiotics and low molecular weight Heparin. All patients were seen at six weeks, three months and annually after surgery. Clinical and radiologic assessment was carried out at each visit.

Fifty-eight hips were available for analysis, 28 in the CoP group and 29 patients in the CoC group. Mean age of both groups was less than 45 years.

There were seven revisions (16%) among the 58 patients enrolled in the study. In the CoP group four patients underwent revision with head and liner exchange for eccentric polyethylene wear 16 years post-implantation. In the CoC group one patient had a cup revision at 15 years for acute aseptic instability of the acetabulum; two additional patients in the CoC group had femoral head exchange, one for fracture and one for trunnion corrosion. Both occurred 14 years after the index surgery.

Functional outcome scores showed no difference between the two groups at 15 years. Radiographically there was a statistically difference in wear between the two groups.

This study demonstrates that both ceramic-on-ceramic and ceramic-on-polyethylene produce satisfactory functional results with low revision rates in young patients.

We assessed the clinical and radiological outcome of a single uncemented total hip replacement (THR) after twenty years, analysing polyethylene wear and osteolysis.

82 hips implanted between 1992 and 1995 were prospectively evaluated. Mean follow-up was 20.6 years (18–23). A hemispherical porous-coated cup matched to a proximally hydroxyapatite-coated anatomic stem. A 28mm PE liner, sterilised by gamma irradiation in air, was used in all hips. Radiological position, eventual loosening and osteolysis were recorded over time. Penetration of the head into the liner was measured by the Roentgen Monographic Analysis (ROMAN) Tool at 6 weeks, 6 months, one year and yearly thereafter.

Six cups were revised due to wear and four cups because of late dislocation. All stems showed osseointegration and all cups appeared radiographically well-fixed. Six unrevised hips showed osteolysis on the acetabular side and two hips on the proximal femur. Creep at one year was 0.30±0.23 mm. Mean total femoral head penetration was 1.23mm at ten years, 1.52mm at 15 years and 1.92mm at 23 years. Overall mean wear was 0.12±0.1 mm/year and 0.09±0.06 mm/year after the creep period. Mean wear was 0.08±0.06 mm/year in hips without osteolysis and 0.14±0.03 mm/year in hips revised or hips with osteolysis (p<0.001).

Although continued durable fixation can be observed with porous-coated cups and proximally hydroxyapatite-coated anatomic stems, true wear continues to increase at a constant level over time. PE wear remains as the main reason for osteolysis and revision surgery in uncemented THR after twenty years.

We report on an innovative surface grafting to highly crosslinked (HXLPE) bearing for THA using a biocompatible-phospholipid-polymer poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC). Such hydrophilic surfaces mimic articular cartilage and are hypothesized to improve lubrication and thereby reduce friction and wear.

We performed in vitro testing of wear and friction of ceramic-on-polyethylene THRs with the PMPC treatment, and compared them with untreated controls. Highly cross-linked UHMWPE bearings, gamma-ray-irradiated at different levels with and without vitamin E (HXL Vit. E: 125 kGy, HXL: 75 kGy, respectively) were divided so half were PMPC treated (n=3 for all four groups). All were paired with identical 40 mm diameter zirconia-toughened-alumina ceramic heads. Testing was carried-out on an AMTI hip simulator for 10 million simulated walking cycles with standard lubricant and conditions (ISO-14242-1). Wear was measured gravimetrically at 21 intervals, and so was frictional torque with a previously described and tested methodology.

PMPC treatment produced a statistically significant 71% in wear reduction of HXL poly (1.70±1.36 mg/Mc for PMPC vs. 5.86±0.402 mg/Mc for controls, p=0.013). A similar significant wear reduction was found for PMPC treated HXL with Vit. E liners (0.736±0.750 mg/Mc, vs. 2.14±0.269 mg/Mc, p=0.035). The improvements were associated with 12% and 5% reductions in friction of the HXL and Vit. E HXL respectively (statistically significant p=0.003, and marginal p=0.116, one tailed).

These results were an important step in the quest for lower wearing, thin and strong UHMWPE liners for larger diameter femoral heads with the potential benefit of longevity and less risk of dislocation after surgery.

The primary purpose of the current study was to evaluate and compare the wear properties of vitamin E-doped, highly-crosslinked PE (VEPE) and one formulation of moderately cross-linked and mechanically-annealed ultra-high molecular weight PE (ModXLPE) in patients five years after primary THA. We also sought to understand whether polyethylene wear is associated with radiographic evidence of bone resorption or with deterioration in patient-reported outcome measures (PROMs).

A total of 221 patients from four international centers were recruited into a prospective RSA and clinical outcomes study. Seventy percent (76%) of patients received VEPE (vs. ModXLPE) liners, and 36% received ceramic (vs. metal) femoral heads. PROMs and radiographs were collected preoperatively and at one, two, and five years postoperatively. In addition, RSA radiographs were collected to measure PE wear.

We observed similar bedding in through the one-year interval and wear through the two-year interval between the two liner types. However, there was significantly more femoral head penetration in the ModXLPE cohort compared to the VEPE cohort at the five-year follow-up (p<0.001). The only variables independently predictive of increased wear were ModXLPE (vs VEPE) liner type (β=0.22, p=0.010) and metal (vs. ceramic) femoral head type (β=0.21, p=0.013). There was no association between increased wear and radiolucency development (p=0.866) or PROMs. No patients were found to have evidence of osteolysis.

At five-years postoperatively, patients treated with VEPE (vs. ModXLPE) and ceramic (vs. metal) femoral heads demonstrated decreased wear. At the longest follow-up (five years postoperatively), the wear rates for both liner groups were very low and have not led to any osteolysis or implant failures via aseptic loosening.

We evaluated (1) wear rate, (2) prevalence and volume of osteolysis using 3D-CT scan, (3) other bearing-related complications, (4) HHS and survivorship free from revision at 15 years after THA using first-generation XLPE (1G XLPE).

One-hundred sixty THAs were evaluated regarding bearing-related complication, HHS and survivorship. Among them, 112 hips underwent 3D-CT to analyze wear rate and osteolysis. All THAs were performed by single surgeon using cup of identical design, a 28-mm metal head and 1G XLPE (10 Mrad). Average age were 57 years and mean follow-up was 15.2 years. 3D-CT scan was performed at average of 13.0 years. Clinical evaluation included HHS and radiographic analysis was performed regarding stem alignment, cup anteversion and inclination angle, component stability, wear rate and osteolysis. Wear was measured using digital software. The prevalence and volume of osteolysis were also evaluated. Complications included XLPE dissociation/rim fracture, dislocation, periprosthetic fracture, infection, HO and any revision. Survivorship free from revision at 15 years was estimated.

Average inclination and anteversion angle of cups were 40.7° and 20.6°. Mean stem alignment was 0.1° valgus. Average bedding-in and annual wear rate wear rate was 0.085 mm and 0.025 mm/yr. Eleven hips (10%) demonstrated osteolysis; pelvic osteolysis with average volume of 1.4 cm³ in six and femoral osteolysis with mean size of 0.4 cm² in seven hips. Of 160 THAs, 5 hips (3%) dislocated. Overall, bearing-related complications occurred in 16 hips (10%). Other complications included postoperative periprosthetic fracture in 4 (3%), infection and HO in 3 hips, respectively. No hip demonstrated loosening, XLPE rim fracture/dissociation. Seven THAs (4%) were revised; recurrent dislocation in 5 and periprosthetic joint infection in 2 hips. Average HHS at last follow-up improved from 47.7 preoperatively to 91.2 points (p<0.001). Estimated survivorship free from revision at 15 years was 95.6 %.

THA using 1G XLPE demonstrated low wear rate as well as low incidence of osteolysis at average follow-up of fifteen years. Longer-term studies will be necessary to determine if XLPE will continue to demonstrate this improved osteolysis characteristics.

Widespread use of XLPE has reduced the incidence of both revision surgery and dislocations. This paper aims to create gross estimates of the magnitude of the resulting cost savings.

Data about decreasing rates of revision surgery and dislocations after THA, comparing XLPE versus CPE, were obtained from the literature along with figures for costs. Gross estimates were generated from these figures.

AOA NJRR 17 reports that at 15 years XLPE reduced the “all cause” revision rate of ceramic on polyethylene by 6.8% and at 16 years reduced the rate for metal on polyethylene by 6.5%. Their average 15 year figure was 4.8%, nearly in half. Dislocations were reduced by 24%. Other data substantiate these trends.

Inclusive costs of nonseptic revisions in US dollars, incorporating those relevant costs for the year prior to and the year following surgery, have been shown to average in the neighborhood of $55,000. Dislocations add further to the costs. The estimated savings from XLPE by 15 years on those total hip replacements done in one year in North America equal nearly $1 billion, even without incorporating any increase annually in the number done. While the specific savings in other countries with lower costs are less, similar proportions likely obtain. Despite all the assumptions, the magnitude is striking.

In addition to major benefits to the patients, the surgeons, and the hospitals, XLPE affords a massive advantage economically.

Trunnionosis is an important failure mechanism of total hip arthroplasties as has recently been reported by the England and Wales national joint registry. Adverse local tissue reaction has also recently been associated with total hip arthroplasty (THA) with metal on polyethylene and ceramic on polyethylene articulations. The contributing factors in the mechanism of this failure pattern have not been elucidated, however they are likely multifactorial to include corrosion, fretting, taper design, implantation time, metal particulate debris, and wear at the metal on metal interface. Furthermore, dissimilar metallic combinations have been shown to exacerbate tribocorrosion. Authors have also reported on the use of ceramic heads to reduce trunniononis, however, tribocorrosion is still present. The majority of the literature regarding modular head neck taper fretting and corrosion involves cobalt chrome (CoCr) alloy. Little is known about head neck fretting corrosion with Oxinium femoral heads.

To measure fretting, corrosion, and wear on the female tapers of retrieved Oxinium femoral heads and to determine how demographic and device factors affect these measurements.

Ninety-two (92) retrieved 12/14 Oxinium heads were graded using the modified Goldberg score for subjectively grading corrosion and fretting on the taper surface. A novel silicone molding technique was validated, then applied to the female tapers of the retrievals and of two pristine Oxinium femoral heads, sizes 32+0 and 32+4. The molds were scanned using a Konica Minolta 3D laser scanner for reconstruction of the topography, dimensions, and surface features of the tapers. Geomagic software was used to align the retrieved to the pristine 3D models, allowing measurement of surface deviations (from wear) that had occurred while the heads were implanted. Patient demographic and implant data were correlated with Goldberg scores and wear deviations.

The mean Goldberg score was 1.6. Goldberg scores of 1 (minimal), 2 (mild), and 3 (moderate) were present in 41 of the 92 heads (45%), 43 heads (47%), and 8 heads (8%) respectively. No implants received a score of 4 (severe). A positive significant correlation was found between length of implantation and increased female taper fretting (R = 0.436, p < 0.01). Wear deviations were significantly greater with 36mm heads compared to 32mm heads (p < 0.01) and with +4 offsets compared to 0 offsets (p = 0.013).

Similar to previous work analyzing ceramic heads, Oxinium heads demonstrated predominately mild tribocorrosion grades, however do not eliminate tribocorrosion. Tribocorrosion was increased with large heads and increased offsets. This finding is consistent perhaps with greater mechanical burden that larger implants with increased offsets experience. Further investigation is needed to elucidate if Oxinium femoral heads reduce fretting and corrosion when compared to CoCr femoral heads.

The purpose of this study was to evaluate the functional and oncological outcome of recycled autograft reconstruction after a wide excision for primary malignant bone tumor around the hip.

From 1998 to 2015, 67 patients with a primary malignant bone tumor involving proximal femur or periacetabular zone (P2) were included. There were 36 males and 31 females with a mean age of 34 years (13 to 58). Of these, 29 patients had grade I or II chondrosarcoma, 28 high-grade osteosarcoma, 6 Ewing's sarcoma and 4 undifferentiated pleomorphic sarcoma. Enneking stage of all 67 patients was stage II. Of the resection classification, proximal femur resection was performed in 29 patients, P1+P2 in 15, P2+P3 in 14, P1+P2+P3 in 4, P2 only in 4, and P2+proximal femur in 1. Extracorporeally irradiated recycled autograft and liquid nitrogen frozen autograft were performed in 44 and 23 patients, respectively.

At a mean follow-up of 98 months (10 to 239), 48 patients (72%) were continuously disease-free, 12 (18%) died of disease and 7 (10%) were alive with disease. The tumors of these patients who had died of disease were usually located in pelvic bones (10/12). Of these 37 patients with pelvic tumors, 7 patients (22%) had local recurrence, four of them received external hemipelvectomy. Other complications included hip dislocation in 2 patients, nerve injury in 2 and deep infection in 2. However, the above complications were rarely occurred in the patients with proximal femur reconstruction. The mean Musculoskeletal Tumor Society functional score were 77% (53 to 93).

Recycled autograft reconstruction for primary malignant bone tumor around the hip is a valid method with acceptable morbidity and a favorable functional outcome.

In recent years, the direct anterior approach (DAA) has become a standard approach for primary total hip arthroplasty (THA). With the increasing use of the DAA in primary cases also more and more revision surgeries are performed through the same interval. With ability to extend the DAA interval proximally and distally, loose cups, loose stems, and even periprosthetic femoral fractures (PPF) can be treated. Especially, PPF are devastating complications causing functional limitations and increased mortality. Therefore, we conducted a study to report the outcome of surgical treatment of PPF with the DAA interval.

We report on the one year complications and mortality in 40 cases with a mean clinical follow-up of 1.5 years. Mean age of patients was 74.3 years. Fractures were classified as Vancouver B2 (36), and B3 (N=4). In 14 cases, a standard stem was used, and in 26 cases a modular revision stem. In 30 cases, a distal extension +/- tensor release was used, in 4 cases a proximal tensor release was done, and in the remaining 6 cases revision could be performed without extension of the approach.

Median cut/suture time was 152 minutes (IQR 80 – 279). The overall complication rate in our patient group was 12.5%. 2 patients died in the first three months after operation. One patient had a transient femoral nerve palsy, which completely recovered.

The DAA interval to the hip for the treatment of PFF showed similar results compared with other approaches regarding mortality, complications, fracture healing, dislocation rate and clinical results. We conclude that femoral revision in case of PPF in the DAA interval is a safe and reliable procedure. Each Vancouver type of periprosthetic fracture can be treated by use of this approach.

Arthroplasty registries have played a key role in the treatment of patients with various joint diseases and conditions since their conception. Swedish hip and knee arthroplasty registries were initiated in late 1970's. The main aim of registries was to create feedback to surgeons. During the last two decades with introduction of patient reported outcomes, data from registries have been increasingly used to compare caregivers and to improve quality of health care. According to the Swedish Hip Arthroplasty Register (SHAR) Sahlgrenska University Hospital had been underperforming during years 2006–2012. In order to improve the outcomes a systematic data driven approach using local and national registries, based on value based management was undertaken.

Representatives from all categories of healthcare staff and patients were invited to join a newly initiated group. The group was asked to define which measurement that contributed most to improve healthcare. Data from SHAR and local registries were used and seventeen different areas of improvement were identified. Several workgroups were initiated.

Between years 2013 and 2017 there was an increase of 60% in the annual volume of elective THAs. The length of stay decreased from 6.4 days to 1.8 days. Satisfaction with outcome of surgery increased from 76% to 90%. Adverse events decreased from 28% to 10%. The risk of re-operations within 2 years decreased from 2.4% to 1.9%.

Data from a national and a local registry were used to identify and implement changes in a large university hospital. Engaging member of staff and creating a graphical tool for continuous feedback drastically improved the quality of care whilst increasing the availability of hip replacements and reducing costs. This project demonstrates the power of registry data and a patient centered approach in engaging staff and improving healthcare.

The purpose of this study was to examine a cohort of patients with minor acetabular dysplasia features in order to identify the preoperative clinical characteristics and imaging findings that differentiate patients with hip instability from patients with impingement.

A retrospective cohort study of patients with borderline acetabular dysplasia was performed. All patients were identified by prospective radiographic evaluation with an LCEA between 20° and 25°. Multivariate statistical analyses were used to identify independent predictors of disease type.

Of the 143 hips in the cohort, 39.2% (n=56) had the diagnosis of instability, while 60.8% (n=87) had the diagnosis of impingement. The cohort included 109 females (76.2%) and 34 males (23.8%).

Hips with instability had a lower LCEA (21.8° vs. 22.8°; p<0.001), lower ACEA (23.3° vs. 26.6°; p=0.002), a higher AI (11.8° vs. 8.5°; p<0.001), and a lower maximum alpha angle (54.4° vs. 61.1°; p=0.001). The odds of instability increased 1.7 times for each one-degree decrease in LCEA, 1.4 times for each one-degree decrease in ACEA, and 1.1 times for each one-degree increase in acetabular inclination (all p0.003). Female sex was strongly associated with instability.

The instability subgroup had greater range of motion (IRF, 22.7° vs. 12.4°, p<0.001) and total arc of motion (IRF+ERF, 61.2° vs. 47.4°, p<0.001). We identified predictors of diagnosis including: acetabular inclination (1.49, p<0.001), ACEA (0.89, p=0.007), crossover sign (0.27, p=0.014), preoperative mHHS (0.96, p=0.014), IRF (1.10, p=0.001), and age (0.88, p=0.001).

Patients with symptomatic instability tend to have increased acetabular inclination, decreased ACEA, greater functional limitations, younger, greater IRF, while hips with impingement demonstrate the opposite trends.

To characterize the quality of flap tissues and the resident cells in order to provide a scientific rationale for reattaching flap tissues during surgery.

11 acetabular chondral flaps and 3 non-delaminated cartilage samples were resected during open hip surgeries and the anatomical orientation was marked. The viability was measured in 7 flaps with Live Dead staining and the distribution of the extracellular matrix components was investigated in 7 oriented flaps by histology. The chondrogenic potential of the residing cells (P2) was investigated via pellets assays (5 flaps). Their capacity to outgrow from flap particles was tested upon encapsulation in 4mm-diameter fibrin glue discs (6 flaps).

The viability in flaps was 49.4 ± 6.5 % compared to 70.6 ± 8.2 % in non-delaminated cartilage, (not significant). Histology showed a progression of fibrillation from the delaminated side towards the site of attachment. This degraded state correlated with the capacity of the cells to outgrow, with 60.6 ± 33 % of the gel area covered by migrating cells after 4 weeks in culture. However, the cells in flaps showed a decreased chondrogenic potential than chondrocytes from non-delaminated cartilage.

Our findings indicate that flaps contain viable cells that can outgrow from the tissue due to the degraded state of the matrix. The poor chondrogenic property of the cells suggests they are unlikely to produce enough matrix to provide a solid attachment of the delaminated tissue upon migration.

The modified Dunn procedure has the potential to restore the anatomy in hips with slipped capital femoral epiphyses (SCFE) while protecting the blood supply to the femoral head. However, there is controversy about the risks associated with the procedure especially in the most severe capital slips.

Therefore, we report on (1) clinical outcome, (2) the cumulative survivorship with endpoints AVN and/or OA progression and (3) radiographic anatomy of the proximal femur at followup in patients treated with a modified Dunn procedure for severe SCFE.

We performed a retrospective analysis involving 46 hips of 46 patients treated with a modified Dunn procedure for severe SCFE (slip angle >60°) between 1999 and 2016.

Followup averaged 8 years, (range 1–17) with 2 patients lost to followup after one year.

The mean age was 13 years (range 9–19 years). Mean preoperative slip angle was 64° (range 60–90) and 14 out of 46 hips (30%) presented with unstable slips.

Clinical scores and PROMs were evaluated and the hips were followed standard x-rays. Cumulative survivorship (Kaplan-Meier) with three defined endpoints: (1) AVN; (2) progression by at least one OA grade according to Tönnis; (3) non-preserved hip joint.

(1)Mean Harris Hip score (HHS) was 93 points (66–100) and mean Hip Disability and Osteoarthritis Outcome Score (HOOS) was 90 points (67–100) at last followup.

(2)Cumulative survivorship was 93% at 10-year followup. Three hips reached an endpoint. Two hips (4%) had AVN, one of them underwent hip arthrodesis. One hip had OA progression.

(3)Postoperative slip angle was 7° (1–16). Alpha angle on axial radiograph was 39° (26–71) at followup. 41/44 hips (93%) had no OA (Tönnis 0).

The modified Dunn procedure largely corrected slip deformities with low apparent risk of progression to avascular necrosis or osteoarthritis at mean 8-years followup. The AVN rate in severe and unstable (30%) capital slip was 4% (2 hips) with this procedure.

Adolescent and young adult patients with a history of DDH and residual hip dysplasia tend to have an early presentation of symptoms. In these patients, a severe acetabular dysplasia, aspheric femoral head and/or high greater trochanter are often observed. We evaluated the long-term results of rotational acetabular osteotomy (RAO) for symptomatic hip dysplasia in patients younger than 21 years.

We performed 492 RAOs for hip dysplasia from 1987 to 2017. In these cases, patients younger than 21 years at the time of surgery were 40 patients (46 hips). We evaluated 34 patients (40 hips, follow-up rate; 85%) retrospectively. There were 32 females and two males; their mean age at the time of surgery was 17.8 years (12–21). The mean follow-up period was 16.8 years (1–30). In eight hips, isolated RAO was not adequate to correct instability and/or congruency. For these hips, four varus femoral osteotomies, two valgus femoral osteotomies and two greater trochanter displacement were combined with RAO.

The mean clinical score (JOA) was improved from 80 to 90 significantly at the final follow-up. The mean CE angle was improved from −3.4 (−35–10) degrees to 27 (8–42) degrees, acetabular roof angle from 30 (15–60) degrees to 6.7 (−3–30) degrees, head lateralization index from 0.665 (0.5–1.0) to 0.614 (0.429–0.7) postoperatively. Radiographic OA progression was observed in four hips, but no hip was converted to THA.

The RAO is an effective technique for surgical correction of a relatively severe dysplastic hip in adolescent and young adults.

To investigate the clinical results of capsular arthroplasty in the treatment of young patients with unilateral hip dislocation.

We retrospectively evaluated all patients who had the capsular arthroplasty from June 2012 to September 2016 in our department. Hips were evaluated using hip Harris score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. The Tonnis osteoarthritis grade and Severin classification were used to access the radiographic outcomes.

Fifty-nine patients (10 males and 49 females) with an average of 16.8y (range: 8–26y) were followed by a mean of 32.1 months (range: 12.5–66.0 months). The mean HHS was 83.4 (range: 31.2–99) and WOMAC score was 12.3 (range: 0–49) at the final follow up. Multivariate analysis revealed that the poor capsular quality (OR=8.29) was associated with the poor result. The thicker capsule (OR=0.83) and bigger femoral head (OR=0.73) were associated with the good result. There were 15 patients (25.4%) identified as Tonnis grade 0, 21 patients (35.6%) as grade 1, 18 patients (30.5%) as grade 2 and 5 patients (8.5%) as grade 3. According to Severin classification, 28 patients (47.6%) were regarded as class I, 22 patients (37.3%) as II, 7 patients (11.9%) as III and 2 patients (3.4%) as IV. One patient underwent THA after 41.5 months. The joint stiffness was the most common complication (10.2%).

We confirmed the efficacy of the capsular arthroplasty in the treatment of young patients with unilateral hip dislocation. The capsular quality and the size of femoral head were associated with the clinical results.

Periacetabular osteotomy (PAO) is a demanding procedure that puts patients at risk for potentially significant blood loss, and blood transfusions. Avoidance of transfusions in otherwise healthy young patients is important. This project was designed to study the effectiveness of our blood conservation efforts.

178 consecutive PAOs performed in one hospital by one surgeon (RFS) from 2008 to 2016 were reviewed retrospectively. PAO's were performed in other hospitals, too, but a majority were from the study group hospital. Data were collected from digitalized patient office charts and hospital electronic medical records. Collected data were analyzed for categorical associations between blood loss, demographic data, and transfusion risks.

Over the past 27 months, the transfusion rate in 63 consecutive patients has been reduced to Zero. Discontinuation of drains, use of TXA, spinal anesthesia, reducing trigger for transfusion to Hgb of <7, cell saver use in all cases, and careful intraop coagulation, among others, have been incrementally incorporated. The overall transfusion rate was 10.7% for all patients. In the early years of this study, prior to adoption of all of these blood conservation measures, the transfusion rate was 12.5%. Over the past four years the transfusion rate was 1.5%. Over the last two years it has been zero.

There is little data specifically regarding transfusion rates in PAOs but this study establishes that an aggressive approach to blood saving techniques and limitation of bleeding can reduce the risk of transfusion to virtually zero in this population of mostly young patients.

The hip-shelf procedure is less often indicated since the introduction of peri-acetabular osteotomy (PAO). Although this procedure does not modify pelvic shape, its influence on subsequent total hip arthroplasty (THA) is not known. We performed a case-control study comparing THA after hip-shelf surgery and THA in dysplastic hips to determine: 1) its influence on THA survival, 2) technical issues and complications related to the former procedure.

We performed a retrospective case-control study comparing 61 THA cases done after hip-shelf versus 63 THA in case-matched dysplastic hips (control group). The control group was matched according to sex, age, BMI, ASA and Charnley score, and bearing type. We compared survival and function (Harris, Oxford-12), complications at surgery, rate of bone graft at cup insertion, and post-operative complications.

The 13-year survival rates for any reason did not differ: 89% ± 3.2% in THA after hip shelf versus 83% ± 4.5% in the controls (p = 0.56). Functional scores were better in the control group (Harris 90 ± 10, Oxford 41/48) than in the hip-shelf group (Harris 84.7 ± 14.7, Oxford 39/48) (p = 0.01 and p = 0.04). Operative time, bleeding and rate of acetabular bone grafting (1.6 hip-shelf versus 9.5 control) were not different (p > 0.05). Postoperative complication rates did not differ: one transient fibular nerve palsy and two dislocations (3.2%) in the hip-shelf group versus four dislocations in the control group (6.3%).

The hip-shelf procedure does not compromise the results of a subsequent THA in dysplastic hips. This procedure is simple and may keep its indications versus PAO in severely subluxed hips or in case of severe femoral head deformity.

Osteonecrosis of the femoral head (ONFH) is an ischemic disorder that causes bone and bone marrow necrosis. In spite of many studies, the primary cause of ischemia is still unknown. The purpose of this study is to identify the susceptibility genes in ONFH.

We performed a genome-wide association study (GWAS) in 1,602 ONFH cases and 60,000 controls. Stratified GWASs based on the 3 subgroups of ONFH (corticosteroids, alcohol, idiopathic) were also performed. We then evaluated the candidate gene in silico using public databases.

Two loci in 12q24.11–12 and 20q12 showed significant association with ONFH. A stratified analysis suggested that the 12q24 locus was associated with ONFH through the drinking capacity. In the 20q12 locus, LINC01370 was the only gene, which functions were related to the plausible biological pathway for the development of ONFH.

A novel ONFH locus was identified at chromosome 20q12, and LINC01370 was the best candidate gene in this locus.

We investigated the preliminary results of femoral head necrosis treated by modified femoral neck osteotomy through surgical hip dislocation in young adults.

33 patients with femoral head osteonecrosis received modified femoral neck osteotomy through surgical hip dislocation from March 2015. 14 patients who had minimal 12 months of follow-up were reviewed radiographically and clinically (mean follow-up:16 months, 12–36 months). The mean age of the patients 32 years at the time of surgery (ranged from 16 to 42years). There were 6 women and 8 men. The cause of the osteonecrosis was steroid administration in 6, alcohol abuse in 4, trauma in 3, and no apparent risk factor in 1. According to the Ficat staging system, 1 hips was stage II, 9 hips III, and 4 hips stage IV. The posterior or anterior rotational angle was 90–180° with a mean of 143°. Clinical evaluation was performed in terms of pain, walk and range of motion on the basis of Merle d'Aubigné hip scores: 17–18 points are excellent, 15–16 are good, 13–14 are fair, 12 or less are poor.

Recollapse of the final follow-up anteroposterior radiograph was prevented in 13 hips. One patient got 1 mm recollapse 18 months after surgery. No patient got progressive joint space narrowing. The Merle d'Aubigné score was excellent in 7 hips, good in 5, fair in 2.

The preliminary results suggest that modified femoral neck osteotomy through surgical hip dislocation is in favor of young patients. But longer term follow-up is necessary.