The Pavlik harness (PH) is commonly used to treat infantile dislocated hips. Variability exists in the duration of brace treatment after successful reduction of the dislocated hip. In this study we evaluate the effect of prescribed time in brace on acetabular index (AI) at two years of age using a prospective, international, multicenter database. We retrospectively studied prospectively enrolled infants with at least one dislocated hip that were initially treated with a PH and had a recorded AI at two-year follow-up. Subjects were treated at one of two institutions. Institution 1 used the PH until they observed normal radiographic acetabular development. Institution 2 followed a structured 12-week brace treatment protocol. Hip dislocation was defined as less than 30% femoral head coverage at rest on the pre-treatment ultrasound or IHDI grade III or IV on the pre-treatment radiograph. Fifty-three hips met our inclusion criteria. Hips from Institution 1 were treated with a brace 3x longer than hips from institution 2 (adjusted mean 8.9±1.3 months vs 2.6±0.2 months)(p < 0 .001). Institution 1 had an 88% success rate and institution 2 had an 85% success rate at achieving hip reduction (p=0.735). At 2-year follow-up, we observed no significant difference in AI between Institution 1 (adjusted mean 25.6±0.9˚) compared to Institution 2 (adjusted mean 23.5±0.8˚) (p=0.1). However, 19% of patients from Institution 1 and 44% of patients from Institution 2 were at or below the 50th percentile of previously published age- and sex- matched AI normal data (p=0.049). Also, 27% (7/26) of hips from Institution 1 had significant acetabular dysplasia, compared to a 22% (6/27) from Institution 2 (p=0.691). We found no correlation between age at initiation of bracing and AI at 2-year follow-up (p=0.071). Our findings suggest that prolonged brace treatment does not result in improved acetabular index at age two years. Hips treated at Institution 1 had the same AI at age two years as hips treated at Institution 2, while spending about 1/3 the amount of time in a brace. We recommend close follow-up for all children treated for dislocated hips, as ~1/4 of infants had acetabular index measurements at or above the 90th percentile of normal. Continued follow-up of this prospective cohort will be critical to determine how many children require acetabular procedures during childhood. The PH brace can successfully treat dislocated infant hips, however, prolonged brace treatment was not found to result in improved acetabular development at two-year follow-up

We Present the results of radiographic assessment of limb length and offset measurements of the first 50 Corin Mini Hips done at Yeovil District Hospital. All reconstructed Hips were compared with the contra lateral hip for leg length and offset restoration using the method of Murphy et al 2007. Excellent matching with the contralateral hip in terms of leg length and offset were found in 78% of hips and fair matching in 22%. The mean leg length discrepancy was 4 mm and mean offset discrepancy was 2 mm. Our results show that despite using a different paradigm to conventional hip replacements, this stem allows accurate restoration of hip geometry

We report the medium term outcome of a 15 degrees face-changing acetabular cup in THA due to secondary OA in DDH. We analysed 28 Hips in 26 patients who underwent THA between May 2007and September 2009. There were 20 females and 6 males with a mean age of 52 yrs (range 33–68yrs). All patients received a cementless Exceed Advanced Bearing Technology 15° Face-changing cup (Biomet) with a ceramic liner through a posterior approach. A cementless or a cemented femoral stem, with 28 or 32mm Biolox Delta ceramic head, was used in all cases. All patients started full weight-bearing the next day. The average clinical and radiological follow-up was for 50 months (range 36–76 months). The mean Harris Hip Score improved to 94 and the Oxford Hip Score improved to 44. There was 100% survivorship of the hip joint for both components. Post-operative radiographs revealed integration of the cup with no signs of loosening or osteolysis. The mean covered acetabular lip inclination angle was 51 degrees (range 43–61)and the true inclination angle of the bearing was 36 degrees (range 28–46). The clinical results support the use of the cementless 15 degrees face-changing acetabular cup in the dysplastic acetabulum

Increased femoral head size reduces the rate of dislocation after total hip arthroplasty (THA). With the introduction of highly crosslinked polyethylene (HXLPE) liners in THA there has been a trend towards using larger size femoral heads in relatively smaller cup sizes, theoretically increasing the risk of liner fracture, wear, or aseptic loosening. Short to medium follow-up studies have not demonstrated a negative effect of using thinner HXLPE liners. However, there is concern that these thinner liners may prematurely fail in the long-term, especially in those with thinner liners. The aim of this study was to evaluate the long-term survival and revision rates of HXLPE liners in primary THA, as well as the effect of liner thickness on these outcomes. We hypothesized that there would be no significant differences between the different liner thicknesses.

We performed a retrospective database analysis from a single center of all primary total hip replacements using HXLPE liners from 2010 and earlier, including all femoral head sizes. All procedures were performed by fellowship trained arthroplasty surgeons. Patient characteristics, implant details including liner thickness, death, and revisions (all causes) were recorded. Patients were grouped for analysis for each millimeter of PE thickness (e.g. 4.0-4.9mm, 5.0-5.9mm). Kaplan-Meier survival estimates were estimated with all-cause and aseptic revisions as the endpoints.

A total of 2354 patients (2584 hips) were included (mean age 64.3 years, min-max 19-96). Mean BMI was 29.0 and 47.6% was female. Mean follow-up was 13.2 years (range 11.0-18.8). Liner thickness varied from 4.9 to 12.7 mm. Seven patients had a liner thickness <5.0mm and 859 had a liner thickness of <6.0mm. Head sizes were 28mm (n=85, 3.3%), 32mm (n=1214, 47.0%), 36mm (n=1176, 45.5%), and 40mm (n=109, 4.2%), and 98.4% were metal heads. There were 101 revisions, and in 78 of these cases the liner was revised. Reason for revision was instability/dislocation (n=34), pseudotumor/aseptic lymphocyte-dominant vasculitis associated lesion (n=18), fracture (n=17), early loosening (n=11), infection (n=7), aseptic loosening (n=4), and other (n=10). When grouped by liner thickness, there were no significant differences between the groups when looking at all-cause revision (p=0.112) or aseptic revision (p=0.116).

In our cohort, there were no significant differences in all-cause or aseptic revisions between any of the liner thickness groups at long-term follow-up. Our results indicate that using thinner HXPE liners to maximize femoral head size in THA does not lead to increased complications or liner failures at medium to long term follow-up. As such, orthopedic surgeons can consider the use of larger heads at the cost of liner thickness a safe practice to reduce the risk of dislocation after THA when using HXLPE liners.

Introduction

Primary robotic-arm assisted total hip arthroplasty (THA) yields more accurate and reproducible acetabular cup placement, nonetheless, data is scarce in terms of outcomes. The purpose of the present study was to report on patient-reported outcomes (PROMs) in a large group of patients who underwent robotic-arm assisted THA. The authors hypothesized that (1) patients who underwent robotic-arm assisted primary THA would achieve favorable and significant improvement in PROMs, (2) an accurate and reproducible acetabular cup placement with respect to the defined SafeZones would be obtained, and (3) a low rate of THA dislocation would be observed.

Simultaneous bilateral total hip arthroplasties (THAs) present unique and unwarranted dangers to the patient and surgeon alike. These include a significantly increased risk of blood transfusion (up to 50% in contemporary series even with the use of tranexamic acid), longer operative times, longer length of stays, and higher mortality rates in patients with minimal risk factors (age > 75 years, rheumatoid arthritis, higher ASA class, and/or male sex). This is even in light of the fact that the vast majority of literature has a substantial selection bias in which only the healthiest, youngest, non-obese, and most motivated patients are included.

Traditionally, simultaneous bilateral THAs were completed in the lateral decubitus position. This required the surgeon and surgical team to reposition the patient onto a fresh wound, as well as additional prepping and draping. To mitigate these additional limitations of simultaneous bilateral THAs, there has been a recent trend towards utilizing the direct anterior approach. However, this particular approach presents its own unique set of complications such as an increased risk of periprosthetic femoral fracture and early femoral failure, an increased risk of impaired wound healing (particularly in obese patients), potential injury to the lateral femoral cutaneous nerve with subsequent neurogenic pain, and traction-related neurologic injuries. When compounded with the risks of simultaneous bilateral THAs, the complication profile becomes prohibitive for an elective procedure with an otherwise very low morbidity.

It is estimated that approximately 3.1 – 7.7% of the general population suffers from primary osteoarthritis of the hip, with up to 42% of these cases being bilateral. The odds of undergoing a contralateral THA after index unilateral THA range from 16–85%. Up to 20% of these patients have the contralateral THA within 5 years. For this patient population, simultaneous bilateral THA may be an appealing option but it remains controversial. Proponents of bilateral simultaneous THA cite advantages such as a single anesthetic exposure, overall shorter length of hospital stay, quicker recovery, earlier return to function, less time off of work, and potential economic advantages. Only recently has there been more data emerging on patients undergoing simultaneous bilateral THA through the direct anterior approach (DAA). The DAA has the distinct advantage of supine positioning that facilitates easy exposure to both hips without the need to reposition the patient onto a fresh surgical incision while performing the second operation. Recent publications suggest that bilateral simultaneous DAA is a safe procedure and may have economic benefits as well.

At our institution between 2010 and 2016, a consecutive series of 105 patients (210 hips) undergoing simultaneous bilateral DAA THA and a matched group of 217 patients undergoing unilateral DAA THA by the same surgeon at a single institution were reviewed. The two groups were matched by gender, age, body mass index and date of surgery. There were no significant differences between the two groups in terms of early complications. There were 2 complications in the unilateral group that were intraoperative nondisplaced calcar fractures that were treated with a single cerclage cable and 50% weight bearing for four weeks. There were 6 in-hospital systemic complications in the unilateral group compared to 7 in the bilateral group (p = 0.129). In-hospital systemic complications were similar between the two groups and included urinary retention, cardiopulmonary abnormalities, alcohol withdrawal, and nausea / vomiting.

There were a total of 14 30-day follow-up hip-related complications in the unilateral group compared to 5 in the bilateral group (p = 0.06) These complications were similar between the two groups and included wound healing issues, tendinitis / bursitis, deep infection, nerve palsy, stem subsidence, and instability. Intraoperative estimated blood loss (EBL) was 360cc in the unilateral group compared to 555cc in the bilateral group (p < 0.001). The bilateral group had lower postoperative day one (POD1) hemoglobin (9.5 g/dl vs. 10.2 g/dl; p < 0.001). Four percent of unilateral patients required blood transfusion compared to 11% in the bilateral group. There were significant differences between the two groups in terms of distance ambulated on POD1 and length of stay (LOS). On average, the unilateral patients walked 235 feet on POD1 compared to 182 feet for the bilateral patients (p < 0.001). Length of stay was significantly longer in the bilateral group (1.95 days vs. 1.12 days; p < 0.001). All 322 patients involved in the study were discharged to home except for a single patient in the bilateral group who was discharged to a skilled nursing facility.

In conclusion, we found no difference in in-hospital or 30-day complication rates when comparing the simultaneous bilateral group to the unilateral group. The main difference when compared to unilateral surgery is increased blood loss yet this did not directly result in specific complications. Simultaneous bilateral DAA THA can be performed safely and without an unacceptably high perioperative complication rate.

Use of a short femoral stem for total hip replacement is not a new idea. Morrey first reported on the results of the Mayo Conservative Stem (Zimmer) in 1989. A short femoral stem can also be soft tissue conserving by allowing for a curved insertion track avoiding the abductor attachments. These concepts have made use of a short femoral stem attractive for use in less invasive total hip surgical approaches. The goal of a short femoral stem is to be bone conserving and provide preferential stress transfer to the proximal femur. This may make the short stem desirable for most total hips regardless of surgical approach.

The proximal femur has considerable variability in shape, canal size, and offset. This makes a single geometry short stem potentially unstable in some anatomic variants without having a longer stem to resist varus bending moments or obtain diaphyseal stability. The Fitmore Stem (Zimmer) has addressed these anatomic variants by having three different shaped stems with different offsets.

The presenter has implanted over 1,000 short stems, using them for both standard and less invasive surgical approaches, and in all bone types. There is a learning curve when using these short stems. Initially some stems were undersized and inserted in some varus. Thirty-four percent of the first 100 short stems inserted had measurable subsidence. However, all stabilised with no further subsidence. Rarely, subsidence now occurs with attention to pre-operative planning for size and improved surgical technique. The surgical technique for insertion of this short stem is different from a conventional length total hip stem. The canal is broached along a curved track with a posterior and lateral moment applied to the broach. Use of the largest size broach that doesn't sink with moderate impaction forces is necessary to maximally contact the medial and lateral proximal cortices to lessen stem subsidence.

Four of over 1,000 stems have been revised for post-operative peri-prosthetic fracture after falls. Two stems were revised for late infection but were not clinically loose. No stems have been revised for aseptic loosening.

INTRODUCTION:

Management of developmental dysplasia of hip in adult is challenging and needs more to be understood in terms of ideal implant, position of acetabulum and operative technique. Patient may present very late, usually when osteoarthritic changes develop followed by pain. Operative management is difficult because of hypoplastic femoral medullary canal and shallow acetabulum filled with soft tissues. Altered anatomy of neurovascular structures also pose a risk of being injured during surgery.

Introduction

Hip osteoarthritis can be debilitating, often leading to pain, poor kinematics and limiting range of motion. While the in vivo kinematics of a total hip arthroplasty (THA) are well documented, there is limited information pertaining to the kinematics of native, non-arthritic (normal) hips and degenerative hips requiring a THA.

The objective of this study is to evaluate and compare the in vivo kinematics of the normal hip with pre-operative, degenerative hips and post-operative THA.

Between October 2001 and December 2010, 143 patients with developmental dysplasia underwent hip replacement surgery using a conical stem with modular necks (MODULUS) and titanium (Delta PF) and trabecular titanium cups system (Delta TT primary cups) (Lima Corporate, Villanova di San Daniele del Friuli, Italy), with ZTA/ZTA bearing (Ceramtec, Germany). 30 (21.0%) patients had both hips replaced, for a total of 173 implants. Mean age at the time of surgery was 55 years (range 22–81 years).

Dysplasia evaluation was based on the Crowe score (6): 66 (38.1%) hips were classified as 1, 50 (28.9%) as 2, 33 (19.1%) as 3 and 24 (13.9%) as 4.

Mean follow-up was 87 months (range 36–146 months); average Harris Hip Score increased from 42 (range 23–65) preoperatively to 92 (range 76–100) at the last follow-up. Stem revision was required in two cases. Cup revision was necessary in one case, for failed osteointegration.

A postero-lateral approach was used in all cases, with patients lying in a lateral decubitus position. Shortening femoral osteotomy was performed in 5 (2.9%) cases for implant reduction due to excessive tension: oblique osteotomy was employed in 3 cases, using the stem as a fixation device, while subtraction Z-osteotomy with two Dall-Miles cables was used in the other 2 cases. Supra-acetabular bone grafting was performed in 3 cases. In all cases, the cup was implanted at the level of the paleo-acetabulum or in the area between the paleo- and neo-acetabulum.

Head diameters were 28 mm in 54 (31.2%) cases, 32mm in 84 (48.6%) cases and 36mm in 35 (20.2%) cases.

The association of Modulus stem and Delta TT cups showed good long-term clinical and radiographic results, with a Kaplan-Meier survivorship of 98.8% at 12 years (95% CI, 97.1%-100%).

Introduction

The bearing surfaces of ceramic-on-ceramic (CoC) total hip replacements (THR) show a substantially lower wear rate than metal-on-polyethylene (MoP) THR in-vitro. However, revision rates for CoC THR are comparable with MoP. Our hypothesis that an explanation could be adverse reaction to metal debris (ARMD) from the trunnion led us to investigate the wear at both the bearing surfaces and the taper-trunnion interface of a contemporary CoC THR in an in-vitro study.

INTRODUCTION

Mal-positioning of the acetabular component in total hip replacement (THR) could lead to edge loading, accelerated component wear, impingement and dislocation [1,2]. In order to achieve a successful position for the acetabular component, the assessment of the acetabular orientation with reference to different coordinate systems is important [3]. The aims of the present study were to establish a pelvic coordinate system and a global body coordinate system, and to assess the acetabular orientations of natural hips with reference to the two coordinate systems.

Aims

Accurate positioning of the acetabular component is essential for achieving the best outcome in total hip arthroplasty (THA). However, the acetabular shape and anatomy in severe hip dysplasia (Crowe type IV hips) is different from that of arthritic hips. Positioning the acetabular component in the acetabulum of Crowe IV hips may be surgically challenging, and the usual surgical landmarks may be absent or difficult to identify. We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component as assessed by morphometric geometrical analysis and its reliability.

Introduction

Success of total hip replacement (THR) is closely linked to positioning of the acetabular component. Malalignment increases complication rates. Our aim was to describe the anteversion and inclination of the inherent acetabulum in arthritic hips and identify the number that fall out with the ‘safe zone’ of acetabular position described by Lewinnek et al. (anteversion 15±10 degrees; inclination 40±10 degrees).

Introduction

The success of total hip replacement (THR) is closely linked to the positioning of the acetabular component. Malalignment increases rates of dislocation, impingement, acetabular migration, pelvic osteolysis, leg length discrepancy and polyethylene wear. Many surgeons orientate the cup to inherent anatomy of the acetabulum. Detailed understanding of the anatomy and orientation of the acetabulum in arthritic hips is therefore very important. The aim of this study was to describe the anteversion and inclination of the inherent acetabulum in arthritic hips and to identify the number that fall out with the ‘safe zone’ of acetabular position described by Lewinnek et al. (anteversion 15°±10°; inclination 40°±10°).

The success of total hip replacement (THR) is closely linked to the positioning of the acetabular component. Malalignment increases rates of dislocation, impingement, acetabular migration, pelvic osteolysis, leg length discrepancy and polyethylene wear. Many surgeons orientate the cup in the same anteversion and inclination as the inherent anatomy of the acetabulum. The transverse acetabular ligament and acetabular rim can be used as a reference points for orientating the cup this way. Low rates of dislocation have been reported using this technique. Detailed understanding of the anatomy and orientation of the acetabulum in arthritic hips is therefore very important. The aim of this study was to describe the anteversion and inclination of the inherent acetabulum in arthritic hips and to identify the number that fall out with the ‘safe zone’ of acetabular position described by Lewinnek et al. (anteversion 15°±10°; inclination 40°±10°).

A series of 65 hips, all with symptomatic osteoarthritis undergoing THR were investigated. Patients with developmental dysplastia of hip (DDH) were excluded. All patients had a navigated THR as part of their normal clinical treatment. A posterior approach to the hip was used. A commercially available non image based computer navigation system (Orthopilot BBraun Aesculap, Tuttlingen, Germany) was used. Rigid bodies (using active trackers) were attached to pelvis and femur. Anterior pelvic plane was registered using the two anterior superior iliac spines and pubic symphysis. The femoral head dislocated and removed and the labrum and soft tissue were excised to clear floor and rim of the acetabulum. Inner size of the empty acetabulum was sized with cup trials and appropriately size trial fixed with a computer tracker was then aligned in the orientation of the natural acetabulum as defined by the acetabular rim ignoring any osteophytes. The inclination and anteversion were calculated by the software. Surgery then proceeded with guidance of the computer navigation system. The computer software defines the anatomical values of orientation, to allow comparison with radiographs these were converted to radiological values as described by Murray et al. The acetabular inclination in all hips was also measured on pre-operative anteroposterior pelvic radiographs. This was done using digital radiographs analysed with the PACS system (Kodak, Carestream PACS Client, version 10.0). Acetabular inclination was measured using as the angle between a line passing through the superior and inferior rim of the acetabulum and a line parallel to the pelvis as identified by the tear drops, using the method described by Atkinson et al.

All patients were Caucasian and had primary osteoarthritis. There were 29 males and 36 females. The average age was 68 years (SD 8). Mean anteversion was 9.3° (SD 10.3°). Anteversion for males was significantly lower than females with a mean difference of −5.5° (95%CI −10.5°,−0.5°) p = 0.033 but there was no significant difference in the number falling outside the “safe zone”. Mean inclination was 50.4° (SD 7.4°). There was no significant difference between males and females with respect to inclination angle or the number that fell outside the “safe zone”. Overall 69% of patients had a combined inclination and anteversion of the native acetabulum that fell outside the “safe zone” of Lewinnek.

Mean acetabular inclination falls out with the ‘safe zone’. This trend has been seen in a recent study of arthritic hips using CT scans which found that the average angle of inclination in both males and females was greater than the upper limit of the safe zone. This study using CT also demonstrated a statistically significant 5.5° difference between males and females in terms of anteversion. This is the same as the figure we have found in our work. Inherent acetabular orientation in arthritic hips falls out with the safe zone defined by Lewinnek in 69% of cases. When using the natural acetabular orientation as a guide for positioning implants it should therefore not be assumed this will fall with in the safe zone although the validity of safe zones itself is questionable. Variation between patients must be taken into account and the difference between males and females, particularly in terms of anteversion, should also be considered.

Short stems are an option for primary THR, but these are the technical challenges. Stem anteversion is increased with short stems usually above 20 degrees so cup anteversion must be adjusted lower. Offset is better if increased up to 5 mm more because more bony neck is retained and with increased stem anteversion the greater trochanter is more posterior, and both of these increase the risk of bony impingement. Short stems are best in A bone, okay in B bone, not recommended yet in C bone. With standard stems performing so well use caution for conversion to short stems.

Cementless femoral stems of many designs now provide dependable long-term fixation and excellent, near normal function in patients of all ages, sexes and level of activity. However, a number of issues related to cementless stem fixation could be further improved: Optimization of load transfer to proximal femur to minimise fracture risk and maximise bone preservation; Elimination of proximal-distal mismatch concerns, including bowed femurs; Facilitation of femoral stem insertion, especially for Anterior and MIS exposures; Facilitation of revision with implants capable of providing durable fixation for active patients.

The potential benefits of short stem femoral THA implants include: Ease of insertion; Reproducibility of insertion; Avoidance of issues related to proximal-distal anatomic mismatch or variations in proximal femoral diaphyseal anatomy (e.g. femoral bowing); Facilitation of MIS surgical approaches, especially anterior exposures; Optimization of proximal femoral load transfer with consequent maximization of proximal bone preservation.

The purpose of this presentation is to describe the design rationale and characteristics of short (< 120 mm) uncemented primary THA femoral stems and to evaluate the clinical and radiographic results of short stems.

Outcome results extending beyond 10 years support the proposition that short stems of appropriate design provide dependable long-term fixation and equivalent clinical results to those currently achievable with cementless stems of conventional length in patients of all ages, sexes and level of activity.

Purpose

This studyevaluated the results of the acetabular medial wall osteotomy to reconstruct the acetabulum in dysplastic hip during total hip athroplasty.