Risk of simultaneous and delayed breakage of total hip replacement ceramic implants in patients with trauma induced periprosthetic fracture and acetabular shell loosening.

BACKGROUND: Ceramic implant breakage (CIB) in total hip replacement (THR) is a rare incident. A confusion exists between the fragile mechanical behaviour of ceramic materials (brittleness) and fragility in the common sense (easy to break), leading to the misconception that trauma is to blame for these breakages. Trauma has been reported as a cause of breakage by several authors and it is debated whether the burst force can be reached in one single trauma in-vivo. We did a retrospective investigation aiming to determine the risk of CIB associated with a major trauma defined as a periprosthetic femoral fracture (PPFF) or a traumatic loosening of the acetabular shell (TLAS) in ceramic-on-ceramic (CoC) THR. HYPOTHESIS: The impact forces responsible of PPFF and TLAS, which are probably the most important impact forces sustained by patients, are not sufficient to induce immediate or delayed CIB. MATERIAL AND METHODS: We conducted a retrospective study on 31 patients (62 ceramic implants, 31 acetabular liners and 31 femoral heads) with a PPFF or TLAS between January 2010 and January 2022. We reviewed the records and X-rays at the time of the major trauma and at the last follow-up. We searched for simultaneous CIB, and those occurring on the non-explanted ceramic implants at last follow up (delayed CIB). These major traumas occurred in 9 men and 22 women. Median age was 75 years old [20-97years old]. There were 28 PPFF and 3 TLAS. Mean time from THR to trauma was 91.2±67months [2.4-240months]. RESULTS: On X-rays and after intraoperative confirmation, we do not report any simultaneous CIB on the 62 ceramic implants. Treatment consisted of internal fixation for 20 patients with preservation of both ceramic implants for Vancouver A, B1 and C fractures, 8 stem revisions with preservation of acetabular liner for Vancouver B2 and B3 fractures and 3 acetabular shell revisions to dual mobility and ceramic head change for TLAS. Thus, a total of 48 ceramic implants remained implanted (28 acetabular liners and 20 femoral heads). At last follow-up after the index revision (median=36 months [6-100months]), no patient had a delayed CIB. DISCUSSION: Major trauma resulting in a PPFF or TLAS in patient withs a CoC THR did not result in simultaneous CIB. The impact forces during these traumas are not sufficient to induce immediate breakage of the ceramic implants. At a median 3years follow-up we found no delayed CIB. Because CIB is a rare event, longer follow up and larger cohort study is needed to determine if a single high impact trauma can initiate and favour the spread of a crack in the ceramic material leading to a breakage. Considering the high mechanical resistance of the ceramic implants and the absence of CIB during or after a major trauma in our study, patients with CoC bearings should not be restricted in their daily activity to prevent CIB. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Does load-bearing materials influence hip capsule thickness in total hip replacement? An MRI case-matched study.

BACKGROUND: Ceramic-on-ceramic (COC) total hip replacements (THR) have exhibited less instability and late dislocation. Hip capsule plays an important role in hip stability. Different surrounding soft tissue reactions have been observed according to the bearing material used but no study compared these data using MRI investigation. Therefore, we performed a retrospective case control study to compare hip capsule thicknesses according to the bearing materials in THR and in native hips. HYPOTHESIS: Hip capsule is thicker after COC THR compared to ceramic- or metal-on-polyethylene (PE) bearings, or native hips. MATERIALS AND METHOD: Magnetic resonance imaging (MRI) images, combined with a multi acquisition variable resonance image combination (MAVRIC) sequence, was used to measure the hip capsule thickness in 16 patients (29 hips) who had either COC (13 hips, median age at surgery: 64.8 years old, median follow-up at imaging: 2482 days), PE bearings (11 hips, median age at surgery: 48.4 years old (significantly different from COC THR), median follow-up at imaging: 1860 days (NS)), or a native hip with no implant (5 hips). Two independent radiologists measured capsular thicknesses in 4 different zones and were blinded regarding the bearing components. The imaged hips were classified into three groups: native, COC and PE. RESULTS: The COC THR group had the thickest capsules (median 7.0mm, range 2.9-15.5mm). This result was statistically significant (p<0.0001) when compared to PE THR (median 4.9mm, range 2.2-10.5mm), and to native hips (median 4.1mm, range 2.7-6.9mm) measurements, respectively. Furthermore, painful hips had thinner capsules (4.6mm, range 2-10.5) compared to not painful hips (6.8mm, range 2.3-15.5) (p=0.0006). DISCUSSION: This is the first in-vivo study measuring capsular thickness in THR with the objective of measuring variations according to the hip implant materials used. The results revealed a significantly thicker capsule for the COC bearing compared to either PE or native hips, and a thinner capsule in painful hips. LEVEL OF EVIDENCE: III, retrospective non-consecutive cohort study.

Total hip arthroplasty after acetabular fracture: does initial treatment make any difference to the outcome? A 5- to 23-year follow-up with clinical and radiological analysis.

PURPOSE: To determine if initial treatment affects the outcome of total hip arthroplasty (THA) after acetabular fracture. METHODS: 49 patients (49 hips) initially treated non-operatively followed some months later by THA in conjunction with acetabular reconstruction (Group 1) and 29 patients (29 hips) who had undergone THA after a previous osteosynthesis (Group 2) were assessed. The mean follow-up was 11.7 (range 5-23) years. RESULTS: 3 acetabular components were revised for aseptic loosening in Group 1 and 2 in Group 2. The survival rate for cup loosening at 16 years was 90.6% (95% confidence interval [CI], 78.1-100) for Group 1 and 94.1% (95% CI, 86.5-100) for Group 2 (p = 0.76). There were 2 sciatic palsies in Group 2 after osteosynthesis. The mean preoperative clinical score and postoperative range of mobility were better in Group 1. There were more heterotopic ossifications in Group 2. CONCLUSION: Despite the good results found in both groups, THA after previous osteosynthesis for acetabular fractures had more complications than a primary THA in conjunction with acetabular reconstruction.

Periprosthetic Joint Infection in Hip Arthroplasty: Is There an Association Between Infection and Bearing Surface Type?

BACKGROUND: Preliminary studies have raised the question of whether certain prosthetic biomaterials used in total hip arthroplasty (THA) bearings are associated with increased risk of periprosthetic joint infection (PJI). For example, some observational data suggest the risk of PJI is higher with metal-on-metal bearings. However, it is not known whether other bearings-including ceramic bearings or metal-on-polyethylene bearings-may be associated with a higher or lower risk of PJI. QUESTIONS/PURPOSES: The objective of this study was to use a national arthroplasty registry to assess whether the choice of bearings-metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)-is associated with differences in the risk of revision for deep infection, either (1) within 6 months or (2) over the entire period of observation, which spanned 15 years. METHODS: Data from primary THAs were extracted from the New Zealand Joint Registry over a 15-year period. A total of 97,889 hips were available for analysis. Inclusion criterion was degenerative joint disease; exclusion criteria were previous surgery, trauma, and any other diagnosis (12,566 hips). We also excluded a small group of ceramic-on-metal THAs (429) with short followup. The median observation period of the selected group of hips (84,894) was 9 years (range, 1-15 years). The mean age of patients was 68 years (SD ± 11 years), and 52% were women. There were 54,409 (64%) MoP, 16,503 (19%) CoP, 9051 (11%) CoC, and 4931 (6%) MoM hip arthroplasties. Four hundred one hips were revised for deep infection. A multivariate assessment was carried out including the following risks factors available for analysis: age, sex, operating room type, use of body exhaust suits, THA fixation mode, and surgeon volume. Because of late introduction of data collection in the Registry, we were unable to include body mass index (BMI, recording started 2010) and medical comorbidities according to the American Society of Anesthesiologists class (ASA, recording started 2005) in the multivariate analysis. RESULTS: The rate of early PJI (< 6 months) did not differ by bearing surface. In contrast, we observed a difference over the total observation period. Within the first 6 months after the index surgery, CoC THAs were not associated with a lower risk of revision for PJI (p = 0.118) when compared with CoP (hazard ratio [HR], 1.31; 95% confidence interval [CI], 0.50-3.41), MoP (HR, 2.10; CI, 0.91-4.82), and MoM (HR, 2.04; CI, 0.69-6.09). When the whole observation period was considered, CoC hips were associated with a lower risk of revision for deep infection when compared with CoP (HR, 1.30; CI, 0.78-2.18; p = 0.01), MoP (HR, 1.75; CI, 1.07-2.86; p = 0.02), and MoM (HR, 2.12; CI, 1.23-3.65; p = 0.008). CONCLUSIONS: Our finding associating CoC THA bearings with a lower risk of infection after THA must be considered very preliminary, and we caution readers against attributing all of the observed difference to the bearing surface. It is possible that some or all of the observed difference associated with bearing type may have been driven by other factors such as ASA and BMI, which could not be included in our multivariate analysis, and so future registry studies on this topic must assess those variables carefully. LEVEL OF EVIDENCE: Level III, therapeutic study.

Ceramic-on-ceramic THA Implants in Patients Younger Than 20 Years.

BACKGROUND: Poor survival of THA implants in very young patients has been attributed to use of cemented implants, wear of conventional polyethylene, and the presence of morphologic deformities in the proximal femur or in the acetabulum. Few studies have reported the long-term results of ceramic-on-ceramic implants in THAs in patients younger than 20 years. QUESTION/PURPOSES: We determined: (1) the proportion of patients who experienced complications related to the ceramic bearing (squeaking, fracture); (2) the survivorship free from loosening and free from revision for any reason; (3) whether patients with osteonecrosis had inferior survivorship compared with patients whose surgical indication was all other diagnoses including sequelae of pediatric hip disorders (developmental dysplasia of the hip, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis); and (4) clinical function. METHODS: Between 1979 and 2013, we performed 113 primary THAs in 91 patients younger than 20 years at the time of surgery. Of those, 105 THAs (83 patients) were done with ceramic-on-ceramic bearings (91% of the 91 patients); during that period, a ceramic-on-ceramic bearing couple was indicated in all patients younger than 20 years. In eight patients (eight hips), a cemented polyethylene cup was implanted because the diameter of the acetabulum was smaller than the smallest available ceramic cup (46 mm), or because adequate fixation of a ceramic press-fit cup could not be achieved despite careful reaming of the acetabulum. The most common diagnosis indicating THA was avascular necrosis of the femoral head (56.2%; 59 hips). Thirty-five patients (40 hips) had undergone previous operations before the replacement. Three patients (4%; four hips) died from unrelated causes, nine patients (11%; 13 hips) were lost to followup, and four patients (five hips) had a followup greater than 8.5 years but have not been seen in the last 5 years. Patients were assessed clinically (using the Merle d'Aubigne-Postel score, Hip disability and Osteoarthritis Outcome score (HOOS), and the SF-12(®) Health Survey, and radiographically for signs of radiolucencies, subsidence, or osteolysis on plain films. The mean followup was 8.8 ± 6.1 years (range, 2-34.4 years). RESULTS: Five patients experienced transient noise generation, defined as a snap in four patients and squeaking in one. Seventeen hips underwent revision surgery-16 for aseptic loosening and one for septic loosening. The implant survival rate at 10 years with aseptic loosening as the endpoint was 90.3% (95% CI, 82.4%-98.9%). No hip had acetabular or femoral osteolysis. Survivorship in patients with osteonecrosis did not differ from survivorship in patients with other diagnoses. The Merle d'Aubigne-Postel score increased from 10.1 ± 4.0 to 17.6 ± 1.1 (p < 0.01); the mean HOOS score was 79.3 ± 13.8 (range, 50.6-100); the mean SF-12(®) physical and mental component scores were 48.1 ± 7.9 (range, 21.4-57.6), and 47.4 ± 12.2 (range, 24.5-99.4), respectively. CONCLUSIONS: We found that patient-reported outcomes scores improved in most patients undergoing THA in this very young study group. Underlying diagnosis did not affect long-term survivorship. However, the revision-free survival rate at 10 years is lower than published estimates in older patients, and with 11% of patients lost to followup, our estimates may represent a best-case scenario. Therefore, we believe THA should be performed as a last resort in this population. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Are ceramic-on-ceramic bearings in total hip arthroplasty associated with reduced revision risk for late dislocation?

BACKGROUND: Dislocation is a major complication after primary total hip arthroplasty (THA), but little is known about the potential relationships between bearing materials and risk of dislocation. Dislocation within the first year after surgery is typically related to either surgical error or patient inattention to precautions, but the reasons for dislocation after the first year are often unclear, and whether ceramic bearings are associated with an increased or decreased likelihood of late dislocation is controversial. QUESTIONS/PURPOSES: The purpose of this study was to use a national registry to assess whether the choice of bearings-metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)-is associated with differences in the risk of late dislocation. METHODS: Data from primary THAs were extracted from the New Zealand Joint Registry over a 10-year period. The mean age of patients was 69 years (SD ± 12 years), and 53% were women. The median followup in this population was 7 years (range, 1-13 years). The surgical approach used was posterior in 66% of THAs, lateral in 29%, and anterior in 5%. The primary endpoint was late revision for dislocation with "late" defined as greater than 1 year postoperatively. A total of 73,386 hips were available for analysis: 65% MoP, 17% CoP, 10% CoC, and 7% MoM. In general, patients receiving CoC and MoM bearings were younger compared with patients receiving CoP and MoP bearings. RESULTS: Four percent of the hips were revised (3130 THAs); 867 THAs were revised for dislocation. Four hundred seventy THAs were revised for dislocation after the first postoperative year. After adjusting for head size, age, and surgical approach, only CoP (hazard ratio [HR], 2.10; p = 0.021) demonstrated a higher proportion of revision, whereas MoP did not (HR, 1.76; 95% p = 0.075). There were no differences of revisions for dislocation in the CoC (HR, 1.60; p = 0.092) and MoM cohorts (HR, 1.54; p = 0.081). CONCLUSIONS: Dislocation is a common reason for revision after THA. The relationships between bearing materials and risk of revision for late dislocation remain controversial. This large registry study demonstrated that bearing surface had little association with the incidence of late dislocation. Future studies with longer followups should continue to investigate this question. LEVEL OF EVIDENCE: Level III, therapeutic study.

Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty.

Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings.

Is there a risk in placing a ceramic head on a previously implanted trunion?

BACKGROUND: Strategies for revising a ceramic-on-ceramic total hip prosthesis are controversial. Some consider reimplantation of a ceramic head on a well-fixed femoral stem inadvisable as it may lead to a fracture of the newly implanted head. QUESTIONS/PURPOSES: We assessed (1) the risk of fracture when a new ceramic head was placed on a previously implanted trunion; (2) the survival rate of the revised hips; and (3) hip function and acetabular and femoral component loosening at midterm followup. PATIENTS AND METHODS: We retrospectively reviewed all 126 patients (139 hips) who had revision of alumina-alumina hip arthroplasties between January 1977 and December 2005. Of these, 99 patients (110 hips) had revision of the socket only with retention of the femoral component. The femoral head was left in place in 33 hips, the same alumina head was re-implanted in seven hips, a new alumina head was implanted in 45 hips, a metallic head in 16, and a zirconia head in nine. Twenty-six patients (29 hips) died and nine (10 hips) were lost to followup before 5 years; this left 71 hips for review. Minimum followup was 60 months (mean, 112 months; range, 60-319 months). RESULTS: Eighteen hips required rerevision surgery, 11 for aseptic loosening, two for septic loosening, two for fracture of a ceramic liner, one for recurrent dislocation, one for ipsilateral femoral fracture, and one for unexplained pain. Among the 61 ceramic heads implanted on a well-fixed stem, no fracture of the head occurred at a mean 88 months' followup. The survival rate at 10 years with mechanical failure as the end point was 81.6%. CONCLUSIONS: We observed no fractures of the ceramic heads implanted on a previous titanium trunion. This approach is possible if inspection shows no major imperfection of the Morse taper.

Decrease in particle-induced osteolysis in ovariectomized mice.

Postmenopausal osteoporosis is a common disorder that results from increased osteoclastic activity caused by estrogen deficiency. Whether postmenopausal bone remodeling can alter the response to particulate debris is unknown. The purpose of this study was to evaluate the bone response to polyethylene particles in an ovariectomized murine model. Polyethylene particles were implanted onto the calvaria of seven control mice and seven ovariectomized (OVX) mice, as compared with calvaria from sham-operated and OVX mice. Calvaria were harvested after 14 days. Skulls were analyzed with a high-resolution micro-CT and by histomorphometry after staining with Stevenel blue and picrofuschine, and for tartrate-specific alkaline phosphatase. As assessed by micro-CT, particle implantation induced a significant decrease in bone thickness in control mice, while bone thickness remained stable in OVX mice. In particle-implanted animals, the osteoclast number was 2.84 +/- 0.3 in control mice and 1.74 +/- 0.22 in OVX mice. Mean bone loss was -12% +/- 1.9% in control mice and -4.7% +/- 1.7% in OVX animals. The reduction of osteolytic response suggests that ovariectomy may have a protective role against particle-induced bone resorption.

[Total hip replacement: current concepts and basic issues]. / Prothèses totales de la hanche. Etat de l'art et problèmes fondamentaux.

Since the pioneering period of the early 1960s, total hip replacement has gained in safety, effectiveness and quality, through advances in anesthesia, pain control and less-invasive surgery. New materials have been developed jointly with engineers. Thirty years ago we started to develop a special friction system with alumina on an alumina couple, which avoids osteolysis due to plastic debris. It has also become possible to implant hip prostheses in young people, permitting normal activity and with the hope of keeping the same prosthesis for many years. The authors also review data on foreign body reactions, biomechanics, and bone remodeling.

Benzylaminated dextran-modified hydrogels: a long-term bioactive TGF-beta1 carrier.

Highly porous dextran-based hydrogels [in which various amounts (up to 16.6%, w/w) of a benzylaminated dextran (DMCB) exhibiting high affinity for TGFbeta1 was immobilized] were developed to achieve long-term retention of bioactive TGFbeta1 in situ. Unmodified hydrogels rapidly desorbed 80-90% compared with only 40-60% of the preloaded TGFbeta1 from the DMCB-modified hydrogels during a period of 21 days in PBS in vitro. TGFbeta1 release experiments (performed with high ionic strength solutions) indicated that formation of the complex between TGFbeta1 and functionalized hydrogels was governed by different interactions, depending on the degree of conjugation with DMCB: ionic interactions in the case of weakly conjugated matrices and nonionic interactions in highly conjugated matrices. Using cells containing a TGFbeta-sensitive luciferase reporter gene, weakly DMCB-modified hydrogels sequestered bioactive TGFbeta1 in situ, giving much higher, long-term signaling performance than highly functionalized hydrogels. Because these biocompatible functionalized hydrogels can provide long-term bioactive TGFbeta1, they could be used as scaffolds for cells to stimulate and regulate human tissue repair processes.

Enhancement of the biological activity of BMP-2 by synthetic dextran derivatives.

In the present study, we explored the binding capacity of synthetic heparin-like dextran derivatives to recombinant human bone morphogenetic protein 2 (BMP-2), a heparin-binding osteoinductive growth factor. Affinity electrophoresis analysis provided evidence that carboxymethylated dextran polymers grafted with high amounts of benzylamide groups (named DMCB) interact with BMP-2. The capability of such polysaccharides to potentiate the growth factor biological activity was then investigated. In vitro, DMCB dose-dependently promoted osteoblast differentiation induced by BMP-2 in C2C12 myoblasts more efficiently than heparin. A screening study provided evidence that the potentiating effects of the dextran derivatives on the BMP-2-induced alkaline phosphatase activity improved with their benzylamide groups content and, therefore, with their affinity for the growth factor. The biological activity of BMP-2 was monitored in the culture medium after 6 days using C2C12 cells (containing a BMP sensitive luciferase reporter gene). Like heparin, DMCB sustained the biological activity of the growth factor; this result suggests that the formation of the BMP-2/DMCB complex may protect the protein from being inactivated. In rats in vivo, DMCB also stimulated ectopic calcification mediated by BMP-2. These data indicate that dextran-based polysaccharides prolong the half-life of the growth factor and promote its biological activity.

Osteonecrosis after allogeneic bone marrow transplantation.

UNLABELLED: Osteonecrosis after bone marrow transplantation is usually severe. Most patients develop acute and chronic graft-versus-host disease requiring a high dose of steroids for a long period of time. Generally ineffective nonoperative treatment in the past has resulted in treatment primarily with total hip arthroplasty (THA). We asked whether THA (1) reliably improved functional status, (2) led to more complications, and (3) THA after bone marrow transplantation was as durable as THA for idiopathic ON. We retrospectively reviewed 77 patients (123 hips) with osteonecrosis. The mean age at surgery was 33 years (range, 15.7-56 years). We performed all arthroplasties with an alumina ceramic bearing coupled with an alumina head 32 mm in diameter. The minimum followup was 2 years (mean, 9.2 years; range, 2-26 years). We documented seven revisions: three for late septic loosening, four for late aseptic loosening. Considering loosening of any component as the end point, the survivorship was 74.8% (range, 58.7%-90.9%) at 10 years. In this difficult situation, we believe the results acceptable. Septic loosening affecting this specific population has to be considered a serious event. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Prolonged hypoxia concomitant with serum deprivation induces massive human mesenchymal stem cell death.

Mesenchymal stem cells (MSCs) have been proposed for the repair of damaged tissue including bone, cartilage, and heart tissue. Upon in vivo transplantation, the MSCs encounter an ischemic microenvironment characterized by reduced oxygen (O2) tension and nutrient deprivation that may jeopardize viability of the tissue construct. The aim of this study was to assess the effects of serum deprivation and hypoxia on the MSC survival rates in vitro. As expanded MSCs are transferred from plastic to a scaffold in most tissue engineering approaches, possibly inducing loss of survival signals from matrix attachments, the effects of a scaffold shift on the MSC survival rates were also assessed. Human MSCs were exposed for 48 hours to (i) a scaffold substrate shift, (ii) serum deprivation, and (iii) O2 deprivation. MSCs were also exposed to prolonged (up to 120 hours) hypoxia associated with serum deprivation. Cell death was assessed by Live/Dead staining and image analysis. The MSC death rates were not affected by the shift to scaffold or 48-hour hypoxia, but increased with fetal bovine serum (FBS) starvation, suggesting that between the two components of ischemia, nutrient deprivation is the stronger factor. Long-term hypoxia combined with serum deprivation resulted in the complete death of MSCs (99 +/- 1%), but this rate was reduced by half when MSCs were exposed to hypoxia in the presence of 10% FBS (51 +/- 31%). These results show that MSCs are sensitive to the concurrent serum and O2 deprivation to which they are exposed when transplanted in vivo, and call for the development of new transplantation methods.