Benjamin F. Ricciardi

Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study

BackgroundAdverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes.MethodsConsecutive patients presenting with ALTR from two major hip implant classes (N = 54 patients with Dual-Modular Neck implant; N = 14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry.ResultsLength of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p < 0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p = 0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p = 0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T-cell relative to B-cell markers in the DMN relative to the MoM group (p = 0.032).ConclusionOur results demonstrate that both implant classes display common features of neo-synovial proliferation and necrosis with a CD4 and GATA-3 rich inflammatory infiltrate. Qualitative differences in corrosion product appearance, macrophage morphology, and lymphocyte distributions were seen between the two implant types. Our data suggests that ALTR represents a histological spectrum with implant-based features.

Causes and Risk Factors for Revision Hip Preservation Surgery

Background: Identifying causes and risk factors for failure of hip preservation surgery is critical to properly address residual pathological abnormalities in the revision setting and improve outcomes in this subset of patients. Purpose: To identify the structural causes of failure in both open and arthroscopic hip preservation procedures and to identify demographic and radiographic risk factors that correlate with the need for revision surgery. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A single-center hip preservation registry was reviewed (N = 1898 procedures in 1600 patients) to identify 147 patients (n = 152 procedures) who had undergone previous pelvic surgery. Exclusion criteria included residual deformity from pediatric hip disease (n = 5 patients). Preoperative demographics, intraoperative findings, radiographic data, and clinical outcome scores were compared between cohorts with and without revision surgery in the registry. Postoperative, short-term patient-reported outcome scores for the revision cohort were described. Results: The most common reason for revision was residual intra-articular femoroacetabular impingement (74.8%), followed by extra-articular impingement (9.5%). The majority of revision cases (78.9%) could be addressed with arthroscopic surgery, with the exception of extra-articular impingement or residual acetabular dysplasia, which necessitated open approaches. Patients who underwent revision were more likely to be female, were younger in age, and had worse preoperative outcome scores than did those in the primary cohort. Abnormal femoral version and the presence of acetabular dysplasia were not significantly different between the revision and primary cohorts. Short-term improvements in patient-reported outcome scores were found in the revision cohort at a mean of 15.0 months from the last revision surgery. Conclusion: Residual intra- and extra-articular impingement were the most common reasons for revision in this cohort. Patients who underwent revision tended to be younger in age, were female, and had worse preoperative hip functional outcomes than did those in the primary cohort. Abnormal femoral version or acetabular coverage was not increased in our revision cohort.

Evaluation and Management of Periprosthetic Joint Infection–an International, Multicenter Study

BackgroundControversies still exist regarding the optimal diagnostic and therapeutic strategies in patients with prosthetic joint infections (PJI).Questions/PurposesHow effective are preoperative and intraoperative cultures in isolating organisms and how do these culture results compare to one another? What are the results of surgical treatment of PJI in the hip and knee in an international, tertiary referral center cohort?Patients and MethodsOne hundred sixteen patients (N = 59 hip PJI, N = 57 knee PJI) were recruited prospectively to registries at three international, tertiary referral centers between December 2008 to November 2011. Retrospective review of prospective registry data including demographics, microbiology results, and operative reports was performed.ResultsPreoperative synovial fluid aspiration yielded an organism in only 45.2% and 44.4% of cases, respectively, for knee and hip PJI. False-negative rates of preoperative aspiration relative to intraoperative culture were 56% and 46% in hip and knee PJI, respectively, with discordance rates of 25% and 21.4%, respectively. Rates of negative intraoperative cultures were 15% in hip PJI and 20.7% in knee PJI. Open debridement with prosthetic retention was the most common initial revision procedure performed (48.3% of hip PJI and 63.8% of knee PJI). This method of revision was successful in 41.3% of hip PJI and 59.4% of knee PJI. Initial failure rates for prosthetic revision was lower than debridement with prosthetic retention but remained substantial in both hip PJI (initial success of one-stage exchange 60% and two-stage exchange 70%) and knee PJI (initial success of one-stage exchange 80% and two-stage exchange 75%).ConclusionDiagnosis and treatment of PJI remains challenging with difficulty in isolating the offending organism and with high rates of prosthetic revision and initial treatment failures. Future advances in organism isolation and international standardization of treatment protocols may improve patient outcomes.

Adverse local tissue reaction (ALTR) associated with corrosion products in metal-on-metal and dual modular neck total hip replacements is associated with upregulation of interferon gamma-mediated chemokine signaling.

Adverse local tissue reactions (ALTR) associated with tribocorrosion following total hip arthroplasty (THA) have become a significant clinical concern in recent years. In particular, implants featuring metal‐on‐metal bearing surfaces and modular femoral stems have been reported to result in elevated rates of ALTR. These tribocorrosion‐related tissue reactions are characterized by marked necrosis and lymphocytic infiltration, which contrasts sharply with the macrophagic and foreign body giant cell inflammation associated with polyethylene wear particle induced peri‐implant osteolysis. In this study, we characterize tribocorrosion‐associated ALTR at a molecular level. Gene expression profiling of peri‐implant tissue around failing implants identifies upregulation of numerous inflammatory mediators in ALTR, including several interferon gamma inducible factors, most notably the chemokines MIG/CXCL9 and IP‐10/CXCL10. This expression profile is distinct from that associated with polyethylene wear induced osteolysis, which is characterized by induction of markers of alternative macrophage activation, such as chitotriosidase (CHIT‐1). Importantly, MIG/CXCL9 and IP‐10/CXCL10 are also elevated at the protein level in the synovial fluid and, albeit more moderately, the serum, of ALTR patients, raising the possibility that these factors may serve as circulating biomarkers for the early detection of ALTR in at‐risk patients.

Nano-analyses of Wear Particles from Metal-on-Metal and Non-Metal-on-Metal Dual Modular Neck Hip Arthroplasty

Increased failure rates due to metallic wear particle-associated adverse local tissue reactions (ALTR) is a significant clinical problem in resurfacing and total hip arthroplasty. Retrieved periprosthetic tissue of 53 cases with corrosion/conventional metallic wear particles from 285 revision operations for ALTR was selected for nano-analyses. Three major classes of hip implants associated with ALTR, metal-on-metal hip resurfacing arthroplasty (MoM HRA) and large head total hip replacement (MoM LHTHA) and non-metal-on-metal dual modular neck total hip replacement (Non-MoM DMNTHA) were included. The size, shape, distribution, element composition, and crystal structure of the metal particles were analyzed by conventional histological examination and electron microscopy with analytic tools of 2D X-ray energy dispersive spectrometry and X-ray diffraction. Distinct differences in size, shape, and element composition of the metallic particles were detected in each implant class which correlate with the histological features of severity of ALTR and variability in implant performance.

Histopathological characterization of corrosion product associated adverse local tissue reaction in hip implants: a study of 285 cases.

BackgroundAdverse local tissue reaction (ALTR), characterized by a heterogeneous cellular inflammatory infiltrate and the presence of corrosion products in the periprosthetic soft tissues, has been recognized as a mechanism of failure in total hip replacement (THA). Different histological subtypes may have unique needs for longitudinal clinical follow-up and complication rates after revision arthroplasty. The purpose of this study was to describe the histological patterns observed in the periprosthetic tissue of failed THA in three different implant classes due to ALTR and their association with clinical features of implant failure.MethodsConsecutive patients presenting with ALTR from three major hip implant classes (N = 285 cases) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy. Clinical characteristics and features of synovial tissue analysis were compared between the three implant classes. Histological patterns of ALTR identified from our observations and the literature were used to classify each case. The association between implant class and histological patterns was compared.ResultsOur histological analysis demonstrates that ALTR encompasses three main histological patterns: 1) macrophage predominant, 2) mixed lymphocytic and macrophagic with or without features of associated with hypersensitivity/allergy or response to particle toxicity (eosinophils/mast cells and/or lymphocytic germinal centers), and 3) predominant sarcoid-like granulomas. Implant classification was associated with histological pattern of failure, and the macrophagic predominant pattern was more common in implants with metal-on-metal bearing surfaces (MoM HRA and MoM LHTHA groups). Duration of implantation and composition of periprosthetic cellular infiltrates was significantly different amongst the three implant types examined suggesting that histopathological features of ALTR may explain the variability of clinical implant performance in these cases.ConclusionsALTR encompasses a diverse range of histological patterns, which are reflective of both the implant configuration independent of manufacturer and clinical features such as duration of implantation. The macrophagic predominant pattern and its mechanism of implant failure represent an important subgroup of ALTR which could become more prominent with increased length of implantation.

Prevention of surgical site infection in total joint arthroplasty: an international tertiary care center survey.

BackgroundPrevention strategies are critical to reduce infection rates in total joint arthroplasty (TJA), but evidence-based consensus guidelines on prevention of surgical site infection (SSI) remain heterogeneous and do not necessarily represent this particular patient population.Questions/PurposesWhat infection prevention measures are recommended by consensus evidence-based guidelines for prevention of periprosthetic joint infection? How do these recommendations compare to expert consensus on infection prevention strategies from orthopedic surgeons from the largest international tertiary referral centers for TJA?Patients and MethodsA review of consensus guidelines was undertaken as described by Merollini et al. Four clinical guidelines met inclusion criteria: Centers for Disease Control and Preventions, British Orthopedic Association, National Institute of Clinical Excellences, and National Health and Medical Research Councils (NHMRC). Twenty-eight recommendations from these guidelines were used to create an evidence-based survey of infection prevention strategies that was administered to 28 orthopedic surgeons from members of the International Society of Orthopedic Centers. The results between existing consensus guidelines and expert opinion were then compared.ResultsRecommended strategies in the guidelines such as prophylactic antibiotics, preoperative skin preparation of patients and staff, and sterile surgical attire were considered critically or significantly important by the surveyed surgeons. Additional strategies such as ultraclean air/laminar flow, antibiotic cement, wound irrigation, and preoperative blood glucose control were also considered highly important by surveyed surgeons, but were not recommended or not uniformly addressed in existing guidelines on SSI prevention.ConclusionCurrent evidence-based guidelines are incomplete and evidence should be updated specifically to address patient needs undergoing TJA.

Patient Characteristics and Early Functional Outcomes of Combined Arthroscopic Labral Refixation and Periacetabular Osteotomy for Symptomatic Acetabular Dysplasia

Background: Symptomatic labral tears are common in patients with acetabular dysplasia; however, optimal treatment of the labrum remains controversial. Purpose: To present patient characteristics and early functional outcomes associated with combined arthroscopic labral refixation and Bernese periacetabular osteotomy (PAO) for symptomatic acetabular dysplasia with a displaced labral tear from the acetabular rim. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing PAO from a single-center prospective hip preservation registry were eligible (N = 73 patients; mean clinical follow-up, 23 months). Indications for combined arthroscopic labral refixation included symptomatic labral injury and MRI findings suggestive of labral detachment from the acetabular rim indicating a repairable tear. The study group consisted of patients undergoing combined arthroscopic labral refixation and PAO (scope/PAO group: n = 21 patients). Patients undergoing PAO alone (PAO group: n = 52 patients) were included as a comparison. Demographic characteristics, pre- and postoperative radiographic findings, and hip-specific functional outcome scores were recorded. Results: The scope/PAO group was older relative to PAO alone (27 vs 23 years; P = .047). Preoperative computed tomography showed increased acetabular version at the 3-o’clock position in the scope/PAO group relative to PAO alone (median [quartile 1, quartile 3]: 24° [20°, 25°] vs 19° [14°, 24°]; P = .026). PAO operative time, achievement of radiographic correction, or postoperative complications did not differ between groups. Improvements by minimum important change for modified Harris Hip Score, Hip Outcome Score (HOS)–ADL, HOS-Sport, and International Hip Outcome Tool (iHOT-33) were seen in 90%, 79%, 74%, and 100% of patients, respectively, undergoing scope/PAO at most recent follow-up. There was greater improvement from baseline in the iHOT-33 at most recent follow-up in the scope/PAO versus PAO group after adjusting for age and Tönnis grade (mean change ± SD: 48 ± 22 [scope/PAO] vs 37 ± 24 [PAO]; P = .03). Conclusion: Patients undergoing combined arthroscopic labral refixation and PAO were older and had increased acetabular anteversion versus patients undergoing PAO alone. Combined arthroscopic labral refixation and PAO was safe, did not affect PAO operative time or radiographic correction achievement, and may benefit clinical outcomes in this patient subset.

In vitro elution characteristics of antibiotic laden BoneSource™, hydroxyapatite bone cement

A calcium phosphate – hydroxyapatite (HA) bone cement was loaded with varying concentrations of tobramycin and vancomycin and the elution properties of these antibiotics were evaluated. Nine groups of antibiotic loaded cement cylinders (N = 6 in each group) were prepared and placed in saline for 28 days. Elution rates of tobramycin and vancomycin from the HA cement were evaluated at high, medium, and low doses of incorporated antibiotic. Tobramycin elution rates did not vary according to dose (0.36, 0.18, and 0.09g). Vancomycin elution rates were also not significantly affected by dose (0.1 , 0.05 , and 0.025 g). The combination of tobramycin and vancomycin increased the elution rate of vancomycin for the medium and low dose of tobramycin. The dose of tobramycin did not affect its elution rate from the cement in the combined groups. Importantly, the concentration of antibiotic eluent stayed above the minimum inhibitory concentration for the entire 28 days for all groups except the medium and low dose of vancomycin alone. Overall, elution rates of both tobramycin and vancomycin in the calcium phosphate-HA cement were comparable to those from polymethylmethacryltate beads in vitro.

Polymethylmethacrylate particles stimulate bone resorption of mature osteoclasts in vitro

Background Interaction between wear particle debris and the cells at the implant-bone interface is an important contributory factor to periprosthetic bone loss seen in arthroplasties. Method To investigate the effect of this particle-induced response on different stages of osteoclast maturation, polymethylmethacrylate (PMMA) particles were added to a murine osteoclastogenic bone marrow cell culture system at either day 0, day 4, or day 8 of culture, which represented PMMA particle stimulation of precursor osteoclasts, mature osteoclasts, or end-stage osteoclasts, respectively. The number of TRAP-posi-tive multinucleate cells (MNCs) and the degree of bone resorption in culture were measured Results Treatment of precursor osteoclasts with PMMA particles resulted in a statistically significant increase in TRAP-positive MNCs that persisted for 4 days, but there was no significant increase in bone resorption. Addition of particles to mature osteoclasts resulted in a significant increase in the number of TRAP-positive MNCs that lasted for 8 days, and also a significant increase in bone resorption. Treatment of end-stage osteoclasts with PMMA particles did not result in an increased number of TRAP-positive MNCs and there was no increase in bone resorption. Interpretation Treatment of mature osteoclasts with PMMA particles resulted in an elevated number of TRAP-positive cells. This persisted over a longer period of time than at the other stages of osteoclast development, and there was also a greater increase in bone resorption.