Large Femoral Head Research Articles

Fretting and Corrosion Damage of Retrieved Dual-Mobility Total Hip Arthroplasty Systems

BackgroundDual-mobility (DM) total hip arthroplasty (THA) systems are designed to increase stability while potentially avoiding problems associated with large femoral heads. Complications of these systems are not yet fully understood. This study aims at characterizing in vivo performance of DM hip systems and assessing modes of clinical failure. MethodsUnder an institutional review board–approved implant retrieval protocol, 18 DM THA systems from 17 patients were included. Implants were graded at the head-neck junction for fretting and corrosion based on the system of Goldberg et al. Components were also macroscopically examined for different damage modes. Demographics and surgical data were collected from medical records, and radiographs were assessed for component positioning. Data were analyzed through Spearman rank-order correlation and Mann-Whitney U-tests, with α = 0.05. ResultsThe average length of implantation was 13.4 months with mild to moderate fretting corrosion damage. Polyethylene (PE) liners exhibited edge deformation, scratching, and pitting damage. Metallic components exhibited burnishing and scratching damage. Summed fretting and corrosion scores were strongly correlated (ρ = 0.967, P < .0001). Summed corrosion score was moderately correlated with presence of embedding on the PE liner (ρ = 0.690, P = .017). PE liner abrasion and edge deformation of the femoral stem taper were moderately positively correlated (ρ = 0.690, P = .017). Fretting and corrosion damage were not significantly correlated with patient demographics or radiographic positioning of implants. There were no differences in scores between modular and monoblock designs. ConclusionThese findings demonstrate that dual-mobility THA systems may be susceptible to the same fretting and corrosion damage observed in traditional modular THA systems. Future studies are needed to confirm these results and clinical significance.

Il cotile a doppia mobilità: una nuova rivoluzione nell’artroprotesi d’anca

Dislocation following Total Hip Arthroplasty (THA) remains the leading reason for revision in the first 2 years. Dual mobility cup (DMC) was developed in France in the early seventies by G. Bousquet and his engineer A. Rambert with the aim of reducing dislocation rate in THA, representing also an alternative to large femoral head. Based on our clinical results and the current literature, DMC is a reliable surgical procedure. In France the dislocation rate has globally decreased from 9.06% in 2005 to 6.10% in 2014. In the field of THA, the DMC may be considered as the second “French revolution”.

Perioperative factors associated with increased length of stay after revision of metal-on-metal total hip arthroplasty

ObjectiveTo investigate patient factors influencing length-of-stay (LOS) after revision metal-on-metal (MoM) total hip arthroplasty (THA). MethodsWe reviewed 23 hips undergoing revision of a MoM THA with minimum 2-year follow-up. A multiple linear regression was calculated to predict LOS using multiple variables. ResultsAverage length of stay (LOS) was 2.1 days. Multiple linear regression analysis identified a significant correlation between presence of an abductor injury (beta = 0.8886; p < 0.0001), patient age (beta = −0.4452, p = 0.0083), and pre-revision head size (beta = 0.4082; p = 0.0172) with LOS (R2 = 0.6351, p = 0.0002). ConclusionPatients with abductor injury, larger femoral heads, and younger age are at risk for longer LOS.

Enhanced stability in total hip arthroplasty

For some patients, total hip arthroplasty (THA) continues to be complicated by postoperative instability and dislocation. The risk of dislocation is markedly higher in patients with predisposing conditions, including coexisting spinal pathology. In these patients, implant design and choice may offer added stability. Larger femoral heads, dual mobility constructs, constrained acetabular liners, and elevated acetabular liners offer enhanced stability in patients who are at risk for postoperative instability. Similarly, pre-operative templating, surgical approach, and surgical techniques such as trochanteric advancement may also influence stability. This review will discuss the evidence, advantages, and disadvantages of the various implant options and surgical techniques for enhancing stability in high risk patients after THA.

Effect of changing femoral head diameter on bony and prosthetic jumping angles.

In THA, using a larger femoral head can increase the oscillation angle and jumping distance. However, there have been no reports which indicate precisely how increasing the jumping distance leads to an increase in the angle from impingement to dislocation (jumping angle). In this study, we clarified the jumping angle of various head diameters and its relationship with pelvic morphology. Using a three-dimensional templating system, virtual THA and ROM simulations were performed in 82 patients. We investigated the distance between bony and prosthetic impingement points and the head centre and calculated the jumping angle for various head diameters. We measured various pelvic shapes and length to clarify the relationship between pelvic morphology and impingement distance. Jumping angles were 7.7° ± 3.2°, 12.1° ± 1.6°, 15.4° ± 2.5° and 10.0° ± 3.0° with flexion, internal rotation with 90° flexion (IR), extension and external rotation (ER), respectively, when we used a 22-mm head diameter. Bony jumping angle increased about 0.5°, 0.8°, 1.0° and 0.7° per 2-mm increase in head diameter with flexion, IR, extension and ER. On the other hand, prosthetic jumping angle remained almost stable at about 31°. Impingement distance was related to pelvic morphology in all directions. Bony jumping angles differed with ROM; the biggest was seen with extension, followed by IR, ER and flexion. On the other hand, bony jumping angle was less than prosthetic jumping angle in all cases. Bony jumping angles differed with ROM; the biggest was seen with extension, followed by IR, ER and flexion. Prosthetic impingement angles were stable. In addition, the bony jumping angle was less than the prosthetic jumping angle in all cases.

Cost Analysis of Dual-Mobility Versus Large Femoral Head Constructs in Revision Total Hip Arthroplasty

BackgroundThe purpose of this study is to report healthcare payer costs of dual-mobility (DM) and large femoral head (LFH) constructs in revision total hip arthroplasties (THAs). MethodsA Markov model was constructed to analyze costs of re-interventions incurred by Medicare and private payers over a 3-year time horizon in patients who underwent unilateral revision THA with DM (n = 126) or LFH (n = 176) implants. Model states and probabilities were derived from prospectively collected registry data. Medicare costs were estimated as the weighted-average national Medicare payment for revision THA. Private payer costs were estimated by using a multiplier of Medicare costs. ResultsOver a 3-year period following revision THA, re-interventions were performed in 11 (9%) DM patients and 34 (19%) LFH patients, costing $263-$1898 in DM THAs and $1285-$3946 in LFH THAs for Medicare. When compared to LFH implants, DM constructs were less costly to Medicare and private payers, resulting in cost differentials of $1536 and $2611, respectively. ConclusionsAt mid-term follow-up, DM constructs utilized in revision THAs were associated with 11% lower absolute risk of re-intervention and payer savings of $1500-$2500 per case when compared to LFH constructs. Level of EvidenceEconomic and decision analysis, Level III.

Using Large Femoral Head as A Bearing Surface in Total Hip Arthroplasty

Using Large Femoral Head as A Bearing Surface in Total Hip Arthroplasty

Hip muscle power recovery after hip replacement using anterior-based muscle-sparing approach in elderly femoral neck fracture: a prospective study in 40 patients.

IntroductionThe early rehabilitation and mobilization after hip arthroplasty (HA) in elderly femoral neck fracture (FNF) patients significantly reduces the postoperative morbidity and mortality. The direct anterior approach (DAA) without the muscle detachment has been shown to improve the early postoperative functional outcomes in coxarthrosis patients. However, the application of DAA on elderly FNF and the most suitable surgical technique have rarely been investigated. This study aimed to report the short-term outcome after our anterior-based muscle-sparing approach (ABMS) in elderly FNF.Materials and methodsA prospective study, in 40 elderly unilateral FNF patients who underwent HA with ABMS, was conducted. The primary outcomes were hip flexion and abduction power at each follow-up period. The contralateral muscle power, measured at 3 and 6 months, was used as the control value. The perioperative data and complications were recorded.ResultsThirty-two patients underwent bipolar hemiarthroplasty (BHA), while eight other patients received total hip arthroplasty (THA). The hip abduction power returned to control value at 6 weeks (99.0%±6.1%; 95% CI: 86.1–111.8). The hip flexion power returned to control at 3 months (108.5%±5.6%, 95% CI: 96.8–120.2). No iatrogenic nerve injury was found. The intraoperative femoral fracture (IFF) was found in 7 patients (17.5%), and was significantly related to the early period of learning skill (first 11 cases; p<0.01). BHA had nonsignificant higher IFF than THA (8 vs. 0; p=0.31).ConclusionAfter ABMS, the hip muscle could recover to the baseline value within 3 months without iatrogenic nerve injury. The ABMS-related complication, which was IFF, could be significantly improved with the learning skill. The adequate posterior soft tissue release and gentle manipulation of the hip joint might play important roles for IFF prevention. BHA might relate to higher risk of IFF because of difficult reduction from large femoral head diameter.

Cadaver-Specific Models for Finite-Element Analysis of Iliopsoas Impingement in Dual-Mobility Hip Implants

BackgroundJoint dislocation is a major cause of failure in total hip arthroplasty. Dual-mobility implants provide a femoral head diameter that can match the native hip size for greater stability against dislocation. However, such large heads are prone to impingement against surrounding soft tissues. To address this concern, the concept of an anatomically contoured dual-mobility implant was evaluated using cadaver-specific finite-element analysis (FEA). MethodsThe stiffness of 10 iliopsoas tendons was measured and also 3D bone models, contact pressure, and iliopsoas tendon stress were evaluated for 2 implant designs according to a previous cadaveric experiment. The iliopsoas interaction with an anatomically contoured and conventional dual-mobility implant was analyzed throughout hip flexion. ResultsThe tensile test of cadaveric iliopsoas tendons revealed an average linear stiffness of 339.4 N/mm, which was used as an input for the FEA. Tendon-liner contact pressure and tendon von Mises stress decreased with increasing hip flexion for both implants. Average contact pressure and von Mises stresses were lower in the anatomically contoured design compared with the conventional implant across all specimens and hip flexion angles. ConclusionsThis study was built upon a previous cadaver study showing reduced tenting of the iliopsoas tendon for an anatomically contoured design compared with a conventional dual-mobility implant. The present cadaver-specific FEA study found reduced tendon-liner contact pressure and tendon stresses with contoured dual-mobility liners. Anatomical contoured design may be a solution to avoid anterior soft-tissue impingement when using hip prostheses with large femoral heads.

Have large femoral heads reduced prosthetic impingement in total hip arthroplasty?

Prosthetic impingement is implicated in dislocation after total hip arthroplasty (THA). While use of larger diameter femoral heads reduces the incidence of dislocation, the effect of larger heads upon impingement rate is unknown. We assessed retrieved THA components for evidence of impingement to determine if large femoral heads reduced the rate of impingement in primary THA and what factors might influence impingement. Liners from 97 primary THAs retrieved at revision arthroplasty were scored for evidence of impingement, defined as wear or deformation on the rim of the component. Component inclination and version were measured from anteroposterior and cross-table lateral radiographs. Independent of revision diagnosis, 77% of liners demonstrated evidence of impingement. Impingement was less prevalent and less severe as head size increased. Severe impingement was observed in 50% of the liners with 28-mm heads, 15% of liners with 32-mm heads, and 21% of liners with 36-mm heads. Regardless of head size, 76% of liners revised for instability demonstrated impingement. Decreased head-neck ratio, use of an elevated liner, increased length of implantation, and increased version were associated with increased severity of impingement. We showed that larger head sizes are associated with decreased incidence of impingement on retrieved acetabular liners when compared to smaller head sizes. Larger heads have reduced but not eliminated impingement, which remains a potential source of instability.

Head size in primary total hip arthroplasty.

The use of larger femoral head size in total hip arthroplasty (THA) has increased during the past decade; 32 mm and 36 mm are the most commonly used femoral head sizes, as reported by several arthroplasty registries.The use of large femoral heads seems to be a trade-off between increased stability and decreased THA survivorship.We reviewed the literature, mainly focussing on the past 5 years, identifying benefits and complications associated with the trend of using larger femoral heads in THA.We found that there is no benefit in hip range of movement or hip function when head sizes > 36 mm are used.The risk of revision due to dislocation is lower for 36 mm or larger bearings compared with 28 mm or smaller and probably even with 32 mm.Volumetric wear and frictional torque are increased in bearings bigger than 32 mm compared with 32 mm or smaller in metal-on-cross-linked polyethylene (MoXLPE) THA, but not in ceramic-on-XLPE (CoXLPE).Long-term THA survivorship is improved for 32 mm MoXLPE bearings compared with both larger and smaller ones.We recommend a 32 mm femoral head if MoXLPE bearings are used. In hips operated on with larger bearings the use of ceramic heads on XLPE appears to be safer.Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170061.

Total hip arthroplasty: Survival and modes of failure.

Total hip arthroplasty (THA) is a very satisfactory surgical procedure for end-stage hip disorders.Implant modifications, such as large femoral heads to improve stability, porous metals to enhance fixation and alternative bearings to improve wear, have been introduced over the last decade in order to decrease the rate of early and late failures.There is a changing pattern of THA failure modes.The relationship between failure modes and patient-related factors, and the time and type of revision are important for understanding and preventing short and late failure of implants.The early adoption of innovations in either technique or implant design may lead to an increased risk of early failure.Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170068

Muscle‐intensive and High‐Impact Exercises Differentially Influence Whole Bone 3D Morphology in Young Outbred Male Mice

Skeletal morphology is predominantly dictated by the genetic background and the habitual loading environment of individual bones. Mechanical loads placed on bones are derived from intracorporeal contractions of muscles and from extracorporeal ground reaction forces generated by bearing weight and by substrate reaction forces during locomotion. We investigated the relative effects of these two sources of load on the growing skeleton using an outbred mouse model system. The 3D shape of the femur was compared across groups of mice following discrete exercise regimens designed to emphasize specific loading environments. Hsd:ICR (CD‐1) mice (N=80; 20 per group) were randomly assigned to one of four treatment groups at four weeks old: swimming which emphasizes muscle forces, dropping which emphasizes impact forces, wheel running which results in a combination of muscle and impact forces, and non‐exercised controls which were free to move about their cages. Durations of swimming, running, and impact loading were matched so that mice received approximately the same intensity. After 20 days mice were euthanized and right hind limbs were micro‐CT scanned (~20 μm3 voxel size). Femoral shape was defined by digitizing 23 landmarks on each scan. To adjust for size, each individual femur was scaled to the geometric mean of all possible linear distances among landmarks. Group differences were analyzed using Euclidean Distance Matrix Analysis (EDMA), and differences &gt;5% were considered substantial. In all three activity groups, we find decreased robusticity of the femoral diaphysis and increased distal condylar breadth compared to non‐exercised controls. Additionally, each group displays unique femoral morphologies when compared to controls. The swimming treatment group shows increased length of the femoral neck. The wheel running treatment group shows a narrower femoral neck with a larger femoral head. The impact loading group shows a lengthened and reoriented distal diaphysis. Overall, the running and swimming groups show similar patterns of morphology that diverge from the non‐exercised mice, suggesting muscle forces differentially affect the loading environment during running in mice compared to impact forces. Further, these results indicate the regional sensitivity of femoral morphology to muscle‐ and impact‐derived loads, and emphasize how activity patterns during adolescence can lead to distinct morphologies in the limb skeleton.Support or Funding InformationResearch support: University of Missouri School of MedicineThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Wear Kinetics of Highly Cross-Linked and Conventional Polyethylene Are Similar at Medium-term Follow-Up After Primary Total Hip Arthroplasty

BackgroundWear debris is a major factor in aseptic loosening of total hip arthroplasty. Ultra high molecular weight polyethylene inlays are known for significant wear, and the following generation, highly cross-linked polyethylene (HCLPE), has shown promising in vitro and short-term in vivo results. This study aimed to investigate wear debris of HCLPE liners with ceramic heads after 9 years to reveal the in vivo wear kinetics of this common bearing combination. MethodsFifty-seven patients (72 hips; 46.5 ± 15.5 years; range 16-76 years) who underwent hip arthroplasty with an HCLPE liner (28- or 32-mm Biolox forte ceramic head) were followed up (mean 9.1 ± 2.4 years; range 3.9-13.8 years). Conventional anteroposterior X-rays were analyzed using Hip Analysis Suite software. ResultsVolumetric wear had a mean of 38.67 ± 22.09 mm3/year, 333.08 ± 183.93 mm3 overall, and linear wear was 0.063 ± 0.03 mm/year and 0.546 ± 0.27 mm overall. Male patients had a significantly higher wear rate (46.42 ± 27.68 mm3/year) and total wear (400.71 ± 235.21 mm3). Larger femoral heads had a significantly higher wear rate (43.10 ± 23.93 mm3/year) and total wear (364.23 ± 203.68 mm3). Regression analysis showed a significant cubic relationship (R2 = 0.307) with increasing yearly wear after approximately 108 months postoperatively. ConclusionsHCLPE liners show significant in vivo wear after 9 years. While the total wear compared to ultra high molecular weight polyethylene liners was decreased, the wear kinetics show a comparable course. The increase in wear rate after only 108 months postoperatively is especially alarming. Longer term follow-up is needed to distinguish the long-term superiority of HCLPE liners in polyethylene-ceramic paired hip arthroplasty.

Evolution of hindlimb bone dimensions and muscle masses in house mice selectively bred for high voluntary wheel-running behavior.

We have used selective breeding with house mice to study coadaptation of morphology and physiology with the evolution of high daily levels of voluntary exercise. Here, we compared hindlimb bones and muscle masses from the 11th generation of four replicate High Runner (HR) lines of house mice bred for high levels of voluntary wheel running with four non-selected control (C) lines. Mass, length, diameter, and depth of the femur, tibia-fibula, and metatarsal bones, as well as masses of gastrocnemius and quadriceps muscles, were compared by analysis of covariance with body mass or body length as the covariate. Mice from HR lines had relatively wider distal femora and deeper proximal tibiae, suggesting larger knee surface areas, and larger femoral heads. Sex differences in bone dimensions were also evident, with males having thicker and shorter hindlimb bones when compared with females. Several interactions between sex, linetype, and/or body mass were observed, and analyses split by sex revealed several cases of sex-specific responses to selection. A subset of the HR mice in two of the four HR lines expressed the mini-muscle phenotype, characterized mainly by an ∼50% reduction in hindlimb muscle mass, caused by a Mendelian recessive mutation, and known to have been under positive selection in the HR lines. Mini-muscle individuals had elongated distal elements, lighter and thinner hindlimb bones, altered 3rd trochanter muscle insertion positions, and thicker tibia-fibula distal widths. Finally, several differences in levels of directional or fluctuating asymmetry in bone dimensions were observed between HR and C, mini- and normal-muscled mice, and the sexes. This study demonstrates that skeletal dimensions and muscle masses can evolve rapidly in response to directional selection on locomotor behavior.

Clinical Faceoff: Instability After THA: The Potential Role of the Bearing Surface.

Clinical Faceoff: Instability After THA: The Potential Role of the Bearing Surface.

Fresh Osteochondral Allograft Transplantation for Treatment of Large Cartilage Defects of the Femoral Head: A Minimum Two-Year Follow-Up Study of Twenty-Two Patients

BackgroundControversy remains over the surgical management of large osteochondral lesions of the femoral head in young, active patients. The purpose of this study is to assess midterm clinical and radiographic outcomes after fresh osteochondral allograft transplantation (OAT) for large femoral head lesions at minimum 2-year follow-up. MethodsA retrospective review of prospectively collected data was performed for 22 patients under the age of 50 years with defined femoral head osteochondral lesions who underwent fresh OAT between 2008 and 2015. Patients were assessed clinically using the modified Harris Hip Score (mHHS) preoperatively and at each follow-up visit. Postoperative radiographs were evaluated for graft integrity and Kellgren & Lawrence Grade for osteoarthritis severity. Complications and reoperation were assessed by chart review. Kaplan-Meier survivorship analyses with 95% confidence intervals were performed for the end point of conversion to total hip arthroplasty. ResultsAt a mean follow-up of 68.8 months (26-113), the mean mHHS improved significantly (P < .001) from 48.9 (19-84) to 77.4 (35-98). Sixteen of 22 patients (72.7%) had an mHHS ≥70 at the latest follow-up. Arthritic progression, as indicated by an increase in the Kellgren & Lawrence Grade, occurred in 4 of 22 hips (18.2%). Five patients (22.7%) underwent conversion to total hip arthroplasty. Graft survivorship was 86.4 ± 7.3% at 2 years, 78.5 ± 10.0% at 5 years, and 67.3 ± 13.5% at 9 years. ConclusionFresh OAT may be a viable treatment option for osteochondral defects of the femoral head in young, active patients with minimal preexisting joint deformity.

CORR Insights®: Otto Aufranc Award: Dual-mobility Constructs in Revision THA Reduced Dislocation, Rerevision, and Reoperation Compared With Large Femoral Heads.

CORR Insights®: Otto Aufranc Award: Dual-mobility Constructs in Revision THA Reduced Dislocation, Rerevision, and Reoperation Compared With Large Femoral Heads.

A rescue method for a large femoral trial head trapped into the cup during direct anterior total hip arthroplasty without using a fracture table

Minimal invasive direct anterior approach (DAA) is an established procedure for total hip arthroplasty (THA). THA via DAA with a larger head size has been reported to reduce the risk of postoperative dislocation. Additionally, variations of the technique exist among different surgeons. Many surgeons prefer a standard surgical table to a fracture table because a standard surgical table less interfere the use of fluoroscopy and facilitates measuring leg length. Here, we presented a rare complication during THA via DAA with a 36 mm large head using a standard surgical table. A 59-y-old woman was diagnosed of bilateral dysplastic hip. The first (right) THA via DAA was done smoothly but a significant postoperative leg length discrepancy (LLD) was noted. To precisely evaluate the LLD in the second (left) THA via DAA, we used a standard surgical table. Intraoperatively, during the last trial reduction, the 36 mm trial head was trapped into the cup and could not be re-dislocated. In the meantime, the surgical table is not helpful for anterior traction to dislocate the head. Then, we decided to chisel the trial head and perform a controlled cracking on the calcar using an osteotome for further sub-siding the stem. Finally, the THA was completed smoothly and the patient did not complain a subjective LLD anymore. We suggest that surgeons should be aware of the slightly different length between the trial stem and the real stem, and should be careful about the selection of head size and type of surgical table in THA via DAA.

Displaced intracapsular neck of femur fractures: Dislocation rate after total hip arthroplasty

Background: Dislocation is one of the most common orthopaedic complications after primary total hip arthroplasty (THA). The reported dislocation rate in elective THR is 5–8%. This number increases up to 22% for THA done for neck of femur (NOF) fractures. Larger femoral head sizes increase the head–neck ratio and range of motion before impingement, therefore reducing the dislocation rate. Due to the reported increase in dislocation for trauma, some surgeons prefer to do a hemiarthroplasty or open reduction and internal fixation (ORIF) rather than a THA.Methods: A retrospective review of all THAs done for NOF fractures during 2006 to 2012 was undertaken at a large referral hospital. Records were reviewed for patient-related and surgical risk factors. We excluded all pathological fractures, extra-capsular fractures and failed ORIF.Results: A total of 92 cases were identified as suitable for analysis. Average age at surgery was 73.2 years (range 30–81). Delay to surgery was 5.3 days (range 1–63). Average follow-up period was 18.3 months (range 3 months to 4.3 years). Four patients (4.3%) had a confirmed dislocation. The four patients who had confirmed dislocation had the following characteristics: 28 mm femoral head size, age over 60 years, two posterior approaches and three females, although not statistically significant.Conclusion: The outcomes of THA in patients with NOF fractures can be favourable and provide good long-term prosthesis survival. We report on low dislocation rate post total hip replacement for intra-capsular NOF fractures.Level of evidence: Level 4