Introduction: Prosthetic Disc surgery is a rapidly growing field in patients with symptomatic degenerative disc disease. Few reports of long-term follow up are yet published, but several authors have published case series including reports of significant complications and difficulties with revision surgery. 1. Advocates of disc replacement surgery have claimed that Osteolysis, whilst being a potential problem associated with artificial disc replacement, has not yet been reported. 2. . Methods: We present what we believe is the first histologically proven case of significant Osteolysis associated with artificial disc replacement in the world literature. We also present a literature review of the laboratory research into performance of artificial disc replacement, focusing on wear debris and particle generation. Results: Our report involves a 42-year-old lady with degenerative disc disease who underwent L5/S1 anterior lumbar interbody fusion in July 1999, with a simultaneous L4/L5 Charite disc prosthesis. In May of 2002 she developed significant back pain, and further investigation, including biopsy revealed polymer disintegration and associated Osteolysis. Attempted revision surgery in May 2003, using a combined anterior approach by a vascular and spinal surgeon, led to damage to the adherent common iliac vessels and inferior vena cava, and the attempt to remove the prosthesis was abandoned. Histological samples taken at surgery confirmed the presence of polyethylene wear debris. Posterior instrumented fusion was performed in June 2003 and the patient made a successful recovery. Discussion: It is important in modern spinal practice to be fully aware of both reported and potential risks of the use of new prostheses. We report an important complication associated with the use of artificial disc replacement. Revision of such prostheses is challenging, and we advise a combined surgical approach

Introduction: Osteolysis is a silent disease with few clinical symptoms until significant bone loss has occurred. Advanced osteolysis, with associated bone loss, can make revision surgery more difficult and compromise the ultimate outcome. In order to delineate the natural history of screw osteolysis in the AMK (Anatomic Modular Knee, Depuy) TKA, a cohort of patient were followed prospectively to determine the incidence and progression of osteolysis. Methods: Between October 1987 and November 1992, 370 patients had 450 uncemented AMK TKA performed at a single institution. Attempts were made to contact all patients in 1993 and 228 patients (280 TKA) agreed to participate in the study. Flouroscopically guided tangential views of the tibial tray were performed and any osteolysis was catalogued by location and graded based on the classification of Lewis et al. Eighty-seven knees had osteolysis for an incidence of 31%, with 52 line, 23 cyst, and 12 cavity. The patients with osteolysis were reassessed 3 years later. No progression was noted in patients with line osteolysis, but two patients with cyst and two patients with cavity had progressive osteolysis. Five knees had been revised for symptomatic osteolysis. This cohort was reassessed by chart and radiograph review in 2000. All patients who initially had cavitary osteolysis had been revised. In addition, 13 patients with cyst osteolysis progressed to cavity and ten knees had been revised. Of the 52 knees that had line osteolysis, 21 progressed to cyst or cavity and 15 knees were revised. Furthermore, 57 additional knees had developed osteolysis with 24 knees being revised. Osteolysis in the AMK is a silent and progressive disorder. We were unable to identify any risk factors that would classify certain patients as at risk for osteolysis. Consequently, we recommend regular periodic follow up in order to recognize osteolysis early

Introduction: Osteolysis is a recognised complication in both cemented and cementless arthroplasty. This may be caused by macrophage mediated reaction to small particulate polyethylene debris. The effective joint space describes the area where polyethylene particles may travel, such as through holes in the cup, to cause a local osteolytic process. Methods: Twenty four cases of osteolysis (in twenty three patients) requiring revision were identified from patients on whom we had performed the primary arthroplasty. These cases were compared to an overall group of 560 primary hip arthroplasty cases performed during the same time and with the same implants. Results: The 24 index cases were revised for osteolysis. This represents 4.3% of the total group in this series of implants. Secondary loosening of the acetabular component was present in 7/24 with 13/24 cups being well fixed at the time of revision. All the cups with secondary loosening had evidence of bone ingrowth & had been undermined by the osteolytic process. In 4 cases, either a pelvic fracture or pelvic dissociation had occurred through an osteolytic lesion. In 21 cases femoral stems were revised, but none of these were loose, and none had significant osteolysis around the stems. The average time from primary procedure to revision was 72 months. The osteolytic group was younger than the overall group at the time of index surgery (53 years vs 63 years, p< 0.0001). There were 16 females and 7 males (p = 0.06). The osteolytic group were also less likely to have an initial diagnosis of primary osteoarthritis than the control group (p=0.05). Other diagnoses in the osteolytic group included dysplasia, previous trauma and inflammatory arthropathy. Acetabular liner thickness was assessed for all patients. The osteolytic group had a significantly higher proportion of cases with polyethylene thickness of less than 7mm (p < 0.005), and less than 6mm (p < 0.0001). There was no difference in the mean height and weight of the two groups. Conclusion: Osteolysis is multifactorial and facilitated by screw holes in the acetabular shell that increase the “effective joint space.” Younger females with small ace-tabular components and thin polyethylene are most at risk. Alternate bearing surfaces or acetabular components without holes may alleviate this problem. These cases represent our experience with osteolytic lesions within the acetabulum requiring revision. There were no cases of cup loosening in our overall group other than the 7/24 that had been undermined by the osteolytic process. Revision to ceramic on ceramic bearing implants is our preferred method of treating this problem

Since the 1970s Swanson implant arthroplasty has become a treatment of choice in metacarpohalangeal (MCP) joint arthroplasty in destructed MCP joints of rheumatoid patients. Sutter (Avanta) implant is also composed of silicone but the centre of rotation is more anatomical, and volar to improve extension moment. Clinical results about these implants have been similar but fracture rates of Sutter implant have been reported to be high. Reason for osteolysis is inflammation reaction to silicone particles released from prostheses due to movement of prosthesis in bone or implant fractures. Reports about osteolysis around Swanson implants present variable result. There is not grading of osteolysis in the literature before and we created a new radiographic grading for osteolysis around silicone MCP implants. Grading is based on involvement of cortical bone: Grade I: Osteolysis varying from a single clear line adjacent to the stem of the prosthesis to a larger, clear area which did not involve the bone cortex; Grade II: Osteolysis affecting the bone cortex to a maximum of one half of the thickness of the cortex; Grade III: Osteolysis affecting the cortex to more than one half of its thickness but not perforating the cortex; Grade IV: Osteolysis perforating the cortex. In this study we compare the incidence of radiographic osteolysis following insertion of 89 Swanson and 126 Sutter MCP implants in rheumatoid arthritis patients. Before surgery hands were randomised one by one to Swanson and Sutter implant groups. The mean follow-up time in the two groups of patients was 57 (40–80) and 55 (36–79) months, respectively. A total of 45 (60%) metacarpal and 40 (53%) proximal phalangeal bones showed no osteolytic changes in the Swanson group. In the Sutter group numbers were 20 (21%) and 26 (27%). In the Swanson group, there was less cortical osteolysis and there were 4 (5%) perforations of a metacarpal and no perforations of a proximal phalanx. In the Sutter group, there were 9 (9%) perforations in a metacarpal and 5 (5%) in a proximal phalanx. (p< 0.001). To create a single independent observation of osteolysis for a hand, the worst osteolysis of a metacarpal or proximal phalanx was recorded. There was only one (5%) perforation in the Swanson group, while there were 8 (30%) perforations in the Sutter group (p=0.011). In all grades of our classification, osteolysis was more frequent in the Sutter than in the Swanson group

Purpose of the study: The alumina-polyethylene bearing has been used for many years but no study has evaluated polyethylene wear and osteolysis with a 32 mm head with a follow-up exceeding 20 years. Material and methods: Thirty-six arthroplasties implanted between 1983 and 1985 (26 patients, mean age 54 years, range 35–65 years) were studied. The same cemented implants were used in all cases, with no loosening. Penetration of the head into the polyethylene was measured annually on digital radiographs and with computer assistance. Osteolysis was quantified in mm. 2. on the merckel. Results: At 20 years follow-up (minimum) or more, penetration of the femoral head into the cup was on average 0.07mm/y. The characteristic feature of the wear curve was the perfect stability after the third year and the absence of any increase over time. Extrapolation of the straight part of the curve to the origin determined the creep. True wear was limited: 0.05mm/y. It was not modified by the polyethylene thickness (eight 52mm cups, twenty-three 50mm and five 48mm). Corresponding volumetric wear was estimated at 640 mm3 at maximum follow-up. At last follow-up, osteolysis measured in mm. 2. on the meckel was 65 mm. 2. on average. In general, this osteolysis appeared around the second year with an imprint on the merckel; it then increased linearly and regularly to the 20th year. Acetabular osteolysis was nevertheless greater than that observed with the Al/Al bearing of controlateral hips implanted at the same period when evaluated on the scan for both hips (20 cases). Discussion: The alumina-polyethylene bearing enables long implant survival for at least 20 years, even for relatively thin polyethylene thicknesses. The characteristic feature of the bearing is the linear polyethylene wear which does not increase with time but remains constant, undoubtedly in relation to the absence of any change in the roughness of the head despite the very long follow-up. Osteolysis remains minimal, but superior to that observed with Al/Al bearings implanted during the same period in controlateral hips

Osteolysis has been reported following ACJ reconstruction with a synthetic graft. We present the first study into its prevalence and pattern, and its effect on patient outcome. Patients who underwent treatment of an unstable ACJ injury using the Surgilig/LockDown implant were identified via our database. Patients were invited to attend a dedicated outpatient clinic for clinical examination, radiographic evaluation, and completion of outcome scoring. Patients who were unable to attend were contacted by telephone. 49 patients were identified. We assessed 21 clinically at a mean of 7 years post-procedure (range 3–11 years). All had radiographic evidence of distal clavicle and coracoid osteolysis. We did not observe progression of osteolysis from the final post-operative radiographs. A further 13 were contacted by phone. The mean Oxford Shoulder Score was 43 (range 31–48) and mean DASH score was 8.5 (range 3–71). The average Patient Global Impression of Change score was 6 (range 2–7). Six patients underwent removal of a prominent screw at a mean of 2 years after surgery; the pattern of osteolysis was no different in this group. All patients had comparable abduction, forward flexion and internal rotation to their uninjured shoulder. We did not observe any relationship between patient demographics, position of implant or etiology and the pattern of osteolysis. Osteolysis of the distal clavicle and/or coracoid is always seen following synthetic reconstruction of the ACJ using this implant, but is non-progressive. Range of shoulder movement is largely unaffected and patient outcomes remain high

Introduction: Osteolysis of the pelvis secondary to polyethylene wear of uncemented acetabular implants has emerged as the most serious and challenging consequence of THR. A very large number of patients have and will continue to receive implants at the risk of being associated with osteolysis. The early detection of osteolysis allows the initiation of treatment programs that preserve bone stock. Because osteolysis occurs and progresses in the absence of clinical symptoms, appropriate follow-up surveillance must be instituted. Our initial study of the usefulness of CT scans in detecting clinically silent and radiographically unobservable osteolysis indicated that x-rays greatly understated the incidence and location of osteolysis. The purpose of this study was to determine the incidence of CT scan identifiable osteolysis in young, active patients with a single cup design and a minimum follow-up of 7 years. Methods: Between 1990–1995, 117 hips (105 patients) underwent an uncemented total hip replacement with a patient-matched femoral component and a titanium plasma sprayed, multi-holed acetabular shell with a compression molded, polyethylene, irradiated in air. 57 patients underwent a CT scan using a metal subtraction software technique. All patients were classified based on their CT scans: Group I: no osteolysis; Group II: cavitary osteolysis; Group III: segmental osteolysis. All patients had standard AP, Frog – lateral and shoot-through lateral radiographs, performed at the time the CT scan was obtained. Results: 37.2% of hips were in Group I, 53.5% in Group II and 9.3% in Group III. No patients in Group I had x-ray evidence of osteolysis (i.e. there were no false negative CT scans). 12% of patients in Group II had x-ray evidence of osteolysis. 22% of patients in Group III had x-ray evidence of osteolysis. There was no correlation between the incidence of osteolysis seen on CT scans with: 1) activity level; 2) age; 3) sex; 4) weight, and 5) size of acetabular component. There was no correlation between polyethylene wear measured using the Martel method and pelvic osteolysis. There was a correlation between the length of implantation and pelvic osteolysis. The average follow-up for patients in Group III was 105.5 months (range 85 – 115) vs. 89.4 months (57 – 117) for Group II and 81.5 months (51 – 112) for Group I. Of the patients with follow-up greater than eight years, 25% had Group III osteolysis. No patients have required revision or polyethylene liner exchange thus far. Discussion: This study indicates that: 1) x-rays are an unreliable method for determining the presence. Location or extent of osteolysis, 2) the incidence of osteolysis based upon CT scans (Group II – III) is 63%; 3) Osteolysis, even if extensive (Group 3) is NOT associated with symptoms; 4) the pattern of osteolysis seen on CT scan strongly suggests that the presence of screws plays an important factor in the process; 5) CT scans are helpful in the planning process for acetabular revision. They allow the precise determination of the location and extent of osteolysis; 6) CT scans are also potentially useful for determining the impact of medical (e.g. alidronate) or surgical (e.g. bone grafting) treatment of osteolysis; 7) CT scans may be very helpful in assessing whether new polyethylenes are associated with reduced osteolysis. The authors strongly recommend that: 1) a surveillance program be established for careful, regular follow-up of patients with THR in place more than 7 years; 2) CT scans be considered as part of that surveillance program, and 3) cups with screws NOT be used routinely in primary THR surgery

Introduction. Periprosthetic osteolysis resulting in aseptic loosening is a leading cause for total hip arthroplasty (THA) failure. Individuals vary in their susceptibility to osteolysis, and it is thought that heritable factors contribute to this variation. We conducted two genome-wide association studies to identify genetic risk loci associated with osteolysis and genetic risk loci associated with time to prosthesis failure due to osteolysis. Patients/Materials & Methods. The Norway cohort comprised 2,624 subjects after THA recruited from the Norwegian Arthroplasty Registry, 779 with revision surgery for osteolysis. The UK cohort comprised 890 subjects recruited from hospitals in the north of England, 317 with radiographic evidence or revision surgery for osteolysis. All subjects had received a fully cemented or hybrid THA using small-diameter metal or ceramic-on-conventional polyethylene bearing. Osteolysis susceptibility case-control analyses and quantitative trait analyses for time to prosthesis failure were undertaken after genome-wide genotyping. Finally, a meta-analysis of the discovery datasets was undertaken. Results. Genome-wide association analysis identified 4 and 11 independent suggestive genetic signals for osteolysis susceptibility at P≤5×10. −6. in the Norwegian and UK cohorts, respectively. Following meta-analysis, 5 independent genetic signals showed suggestive association with osteolysis at P≤5×10. −6. , with the strongest comprising 18 correlated variants on chromosome 7 (lead signal rs850092, Figure 1, p=1.13×10. −6. ). Genome-wide quantitative trait analysis in cases only showed a total of 5 and 9 independent genetic signals for time to prosthesis failure at P≤5×10. −6. , respectively. Following meta-analysis, 11 independent genetic signals showed suggestive evidence of association with time to failure at P≤5×10. −6. , with the largest association block comprising 174 correlated variants in chromosome 15 (lead signal rs10507055, Figure 2, p=1.40×10. −7. ). Discussion. These studies provide the first genome-wide insights into the heritable biology of osteolysis, a major complication of joint replacement surgery. Although there were no dominant signals of genome-wide significance, we find replicating evidence for several independent genetic loci both for osteolysis susceptibility and time to prosthesis failure at P≤5×10. −6. , consistent with the complex aetiology of the disease. Conclusion. The heritable contribution to osteolysis is modest. The identified genetic loci may however provide novel avenues for therapy development in this condition. For any figures and tables, please contact the authors directly

Aim

The osteolytic process of osteomyelitis is, according to textbooks, caused by increased osteoclast activity due to RANKL production by osteoblasts. However, recent findings contradict this theory. Therefore, the aim was to investigate, in a porcine osteomyelitis model, how osteolysis is affected by massive inflammation and RANKL blocking, respectively. In parallel, patients with chronic osteomyelitis, diabetes, foot osteomyelitis, and fracture related infections (FRI) were included for advanced histological analysis of osteolysis.

Aims: Periprosthetic osteolysis, generally ascribed to cup polyethylene debris is the most common reason for revision THR. We carried out a radiological – retrieval study in 63 patients undergoing revision THR in order to explore potential correlation between osteolysis and wear in the cup. Material and Methods: 43 intact polyethylene liners were retrieved following revision THR because aseptic loosening. Radiological osteolysis was assessed from the De Lee and Gruen zones. The linear wear depth in the cups was measured using the shadowgraph technique and the volumetric wear was assessed using the Hashimoto formula. Statistical analysis was performed using the SPSS® software package. Results: There was a statistically significant inverse correlation between Volumetric Wear Rate (VWR)-Total Femoral Osteolysis (TFO) (p=0.024), VWR -Total Osteolysis TO (p=0.003), Volumetric Wear (VW) – TFO (p=0.015), and a trend between VW – TO (p=0.087). This shows that increased levels of osteolysis appear to be associated with lower VWR. Conclusions: Overall these results demonstrate an overall inverse relationship between long term wear of the polyethylene and periprosthetic osteolysis in pre-revision patients. Restriction in the mobility-activity could be a reason for that

The Thompson hemiarthroplasty is a common treatment option for acute neck of femur fractures in the elderly population. Our department noted a significant number of patients returning with thigh pain, radiographic loosening and femoral osteolysis following cemented implantation of the titanium alloy version of the Thompson hemiarthroplasty. We are not aware of any previous reports documenting complications specific to the titanium Thompson implant and a retrospective cohort study was therefore initiated following clinical governance approval.

366 titanium alloy Thompson prostheses were implanted for hip fracture treatment between 2017 and 2020. As of February 2023, 6 of these have been revised at our hospital. 5 were revised for symptomatic femoral osteolysis and 1 presented with an acute periprosthetic fracture. All revised cases were determined to be aseptic. 32 living patients were excluded from recall on compassionate grounds due to permanent nursing home residence. 47 living patients were identified of which 33 attended for xray. 28 deceased and/or nursing home resident patients who had pelvis x-rays in the previous 12 months were also included in the analysis. Including the 6 index hips already revised, a total of 61 hip xrays were analysed, of which 19 hips (31.1%) showed radiographic evidence of femoral osteolysis or loosening.

We conclude that there is a concerning incidence of femoral osteolysis and implant loosening associated with the titanium Thompson implant. We have discontinued use of the implant and reported our experience to the MHRA. We encourage other Scottish Health-Boards who use this implant to consider enhanced follow-up.

Introduction: The Optiplug. ®. bio-absorbable cement restrictor, marketed by Biomet inc., is manufactured from ‘PolyActive’ – a polymer of poly(ethylene glycol) and butylene terephthalate. Biodegradation is thought to be by a combination of hydrolysis and oxidation. The potential benefit – eliminating the need for restrictor removal at future revision surgery – led to Optiplug becoming our cement restrictor of choice over the last 5 years. Anecdotally we have seen marked osteolysis around the distal cement mantle in a number of follow up radiographs in these patients. To date we have not seen an associated peri-prosthetic fracture. We undertook a retrospective, radiographic study to determine incidence, severity and progression of this osteolysis over the first 5 years of follow up. Method: 100 patients for whom 5 year follow up had been undertaken were identified from the departmental database. Patients with loose prostheses and or infection were excluded as were those who had undergone revision surgery. Radiographs from the immediate post operative period, twelve months and five years follow up visits were identified and reviewed. Osteolysis was quantified by calculating the ratio of maximum medullary diameter to the overall cortical diameter of the bone. Comparison was made over time and, where radiographs allowed, to the immediately adjacent femur. Results: 87% of radiographs showed greater than 10% thinning of the cortex at 1 year cf. immediate post op. 5 cases showed greater than 33% thinning. These changes do not appear to progress or regress significantly between 1 and 5 years. Discussion: While marked osteolytic changes appear to be uncommon, some degree of cortical thinning was almost universal in this series. The zone immediately distal to the cement mantle is commonly involved in peri-prosthetic fractures. Any weakening in this area is undesirable

Background: The osteolysis in revision total knee arthroplasty was observed. The purpose of this study was to compare the prevalence and characteristics of osteolysis recognized in revision total knee arthroplasties between the failed mobile bearing and fixed bearing knees. Methods: Eighty revision total knee arthroplasties were done between 1995 and 1998. The primary prosthesis that failed included thirty-four mobile bearing (Low Contact Stress) knees and forty-six fixed bearing knees of vary prostheses. At the time of revision surgery, all the interfaces between bone and prosthesis or cement were routinely checked and recorded for evidence of osteolytic resorption of bone. Preoperative radiographs were assessed independently by two authors for evidence of focal or severe periprosthetic osteolysis. The presence of the lesion was recorded. The demographic data included age and body weight was reviewed. The interval between the primary and revision surgery was recorded. The revision technique was reviewed. A statistical technique of chi-square test was applied in this study. Results: Osteolysis was recognized in sixteen of thirty-four mobile bearing knees (47 per cent) with thirteen knees involved distal femur and in six of forty- six fixed bearing knees (13 per cent) with four knees involved distal femur. The incidence of osteolysis was statistically significant difference between the mobile bearing and fixed bearing knees (p< 0.05). An overall 28 per cent (twenty-two knees) incidence of osteolysis was identified intraoperatively. The overall incidence of osteolysis in distal femur was 21 per cent (seventeen knees). The average time interval from the primary surgery to revision was 108 months. All the knees were affected by osteoarthritis. The most common site of osteolytic bone resorption was the posterior femoral condyle. Conclusions: Comparing to the fixed bearing knees, the mobile bearing (Low Contact Stress) knees were at increased risk for osteolysis in our series. Osteolysis occurred predominantly on the femoral side, especially adjacent to the prostheses in posterior condyle. Radiographic evaluation of osteolysis in distal femur is unreliable

The aim of this study is to assess the extent of osteolysis around a TKR which would then help in effective planning of revision surgery. Osteolysis around a TKR can be difficult to identify in plain radiographs because this typically occurs in low radiodensity cancellous bone of distal femur and proximal tibia. These can often look innocuous and benign allowing the surgeon to fall into a false sense of security. We discuss the use of 3 dimensional CT scan in 7 cases with pre revision initially unsuspected massive osteolysis and its usefulness in planning appropriate implant and/or bone grafting technique in revision surgery. 6/7 knees had a primary cruciate retaining knee implant and the mean time to revision surgery was 11 years and 8 months. Based on our pre operative CT assessment we were able to plan and effectively undertake 3 custom built prosthesis and 4 stemmed revision implants along with the use of adjunct bone additives including allograft. On the basis of this experience we would recommend the routine use of a 3D CT scan in preoperatively assessing a revision TKR and would caution the appearance particularly of the ‘posterior femoral bubble’ as it often belies a large osteolytic cavity

Introduction: Of all hip arthroplasties conducted annually, a proportion will subsequently require revision for aseptic loosening and periprosthetic osteolysis. Osteolysis may develop ‘silently’ and monitoring of patients is recommended. This should include x-rays as progressive changes in size of a lesion may indicate a potential failure. Area measurement of osteolysis has been achieved in a number of ways but with techniques that are not readily available in routine clinical practice. The aim of this study was to develop a method for routine assessment of hip arthroplasty to quantify osteolytic changes seen on x-ray, applicable by any health professional and with good inter-observer reliability. Methods: A morphometric grid is superimposed on an object of interest and the number of test points that fall within a defined area counted. A specialized grid was developed and initial testing was conducted on twenty simulated osteolytic lesions. Subsequent testing was on thirty-five arthroplasty x-rays with evidence of osteolytic lesions. Four observers recorded the number of crosses seen over each lesion. The observers were representative of health professions and levels of experience involved in arthroplasty review. Data was analysed for both inter-observer and test-retest reliability using the intra-class correlation coefficient and the Bland-Altman method (use of two methods provides a better estimation of accuracy). Results: The results for intra-class correlation coefficients on both simulated and actual lesions were all excellent (range 0.90 to 0.98) as confirmed by visual representation using the Bland-Altman method. Discussion: Regular follow-up of hip arthroplasty with x-ray ensures that changes are monitored even when symptoms are absent. We believe that this tool can improve the process through quantitative assessment of osteolytic lesions. The scientific development supports the reliability of the tool when used by a number of raters and the simplicity of application makes it a useful addition to an arthroplasty clinic

Wear debris from implant interfaces is the major factor leading to periprosthetic osteolysis. Fibroblast-like synoviocytes (FLSs) populate the intimal lining of the synovium and are in direct contact with wear debris. This study aimed to elucidate the effect of Ti particles as wear debris on human FLSs and the mechanism by which they might participate in the bone remodeling process during periprosthetic osteolysis. FLSs were isolated from synovial tissue from patients, and the condition medium (CM) was collected after treating FLSs with sterilized Ti particles. The effect of CM was analyzed for the induction of osteoclastogenesis or any effect on osteogenesis and signaling pathways. The results demonstrated that Ti particles could induce activation of the NFκB signaling pathway and induction of COX-2 and inflammatory cytokines in FLSs. The amount of RANL in the conditioned medium collected from Ti particle-stimulated FLSs (Ti CM) showed the ability to stimulate osteoclast formation. The Ti CM also suppressed the osteogenic initial and terminal differentiation markers for osteoprogenitors, such as alkaline phosphate activity, matrix mineralization, collagen synthesis, and expression levels of Osterix, Runx2, collagen 1α, and bone sialoprotein. Inhibition of the WNT and BMP signaling pathways was observed in osteoprogenitors after the treatment with the Ti CM. In the presence of the Ti CM, exogenous stimulation by WNT and BMP signaling pathways failed to stimulate osteogenic activity in osteoprogenitors. Induced expression of sclerostin (SOST: an antagonist of WNT and BMP signaling) in Ti particletreated FLSs and secretion of SOST in the Ti CM were detected. Neutralization of SOST in the Ti CM partially restored the suppressed WNT and BMP signaling activity as well as the osteogenic activity in osteoprogenitors. Our results reveal that wear debris-stimulated FLSs might affect bone loss by not only stimulating osteoclastogenesis but also suppressing the bone-forming ability of osteoprogenitors. In the clinical setting, targeting FLSs for the secretion of antagonists like SOST might be a novel therapeutic approach for preventing bone loss during inflammatory osteolysis.

Purpose: Osteolysis is one of the important issues during the life of noncemented total hip arthroplasty (THA). The purpose of this study was to evaluate a series of 228 THA using an ABG-1 implant to determine the incidence of osteolysis and contributive factors. Material and methods: This series of 228 THA using noncemented ABG-1 anatomic implants coated with hydroxyapatite was implanted in 210 patients, 116 women and 112 men, mean age 62.2 years. The indication was primary osteoarthritis (53.6%), primary necrosis (21.5%), posttraumatic osteoarthritis (11.8%), rheumatoid disease (8.3%) and hip dysplasia (4.8%). The bearings were, 200 zirconium-polyethylene (87.7%), 28 metal-polyethylene (12.3%). At mean 88.6 months follow-up, a minimum 60 months postoperatively, we reviewed 163 patients (37 patients died without revision, 28 (12.3%) were lost to follow-up, and 17 had undergone a revision procedure). We analyzed osteolysis on the digitalized radiograms using the Delee-Charnley classification to which we added a fourth retroacetabular zone. Polyethylene wear was measured with the Imagika(r) software using the method described by Martell. Results: The 17 cup revisions (8.5%) were required for instability (4 pt), loosening (4 pt), osteolysis (4 pt), infection (3 pt), and limping (1 pt). Overall implant survival was 92.1%. Implant survival, considering loosening and osteolysis as failure, was 96.1%. Mean wear at last follow-up was 1.26 mm, for an annual average of 0.17 mm (0.04 – 0.69 mm/yr). Acetabular osteolysis was observed in 41.6% of cases, mainly in the Delee-Charnley zone 1, but was also found in all the other zones. The average surface area was an estimated 223 mm2. Possible factors favoring osteolysis were: aetiology, age, gender, activity level, body mass index, Charnley ABC classification, presence of preoperative acetabular defects, cup size, polyethylene insert thickness, position of the insert rim, cup inclination, complementary fixation, bearing type, polyethylene offset and wear. There was a statistically significant relationship between osteolysis and: the Charnley classification (p=0.012), presence of preoperative acetabular defects (p=0.0034), cup inclination angle (p=0.035), cup size (p=0.042), polyethylene thickness (p< 0.01), use of complementary fixation (p=0.048), and polyethylene wear (p=0.0011). Paradoxically, we did not find any relationship with gender, age, body mass index, and the other factors. Discussion: This analysis demonstrated the determining causes of osteolysis: time, polyethylene thickness, polyethylene wear, the Zicronium-polyethylene bearing. Wear was probably not only the consequence of the Zicronium-polyethylene bearing but was also related to the quality of the polyethylene, and the instability of the insert. Diffuse osteolysis is favored by orifices in the first-generation cups which have been eliminated in the ABG-2 cups

Introduction. Osteloysis following metal-on-UHMW polyethylene Total Hip Arthroplasty (THA) is well reported, as is lack of osteolysis following Ceramic-on-Ceramic (CoC)THA. Early ceramic failures did report some osteolysis, but in flawed implants. As 3rd and now 4th generation ceramic THAs come into mid- and long-term use, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. Osteolysis reported after 3rd generation CoC THA often included metallosis due to neck rim impingement. In our department we have revised only 2 hips in over 6000 CoC THAs for osteolysis. Both had evidence of metallosis as well as ceramic wear. The technique used by Radiologists for identifying the nature of lesions on CT is the Hounsfield score which will identify the density of the tissue within the lucent area. It is common for radiologist to have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA which states there is osteolysis? Revision of such implants in elderly patients has a high risk of morbidity and mortality. Objectives. This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term third generation ceramic-on-ceramic uncemented hip arthroplasties in our department. Methods. Pelvic CT scans were performed on the first 27 patients from a cohort of 301 patients undergoing 15 year review with 3rd generation alumina-alumina cementless THAs. The average follow-up was 15 years (15–17). The CT scans were reviewed against pre-operative and post-operative radiographs and reviewed by a second musculoskeletal specialist radiologist. Results. Eleven of the CTscans were reported to show acetabular osteolysis, two reported osteolysis or possible pre-existing cyst and one reported a definitive pre-existing cyst. After review of previous imaging including pre-operative radiographs, eleven of the thirteen patients initially reported to have osteolysis were found to have pre-existing cysts or geodes in the same size and position as the reported osteolysis, and a further patient had spot-welds with stress-shielding. One patient with evidence of true osteolysis awaits aspiration or biopsy to determine if he has evidence of ceramic wear or metallosis. Conclusions. Reports of osteolysis on CT should be interpreted with care in modern ceramic-on-ceramic THA to prevent unnecessary revision. Further imaging and investigations may be necessary to exclude other conditions such as geodes, or stress shielding which are frequently confused with osteolysis on CT scans

Introduction: Cementless acetabular components have been associated with a higher rate of pelvic osteolysis compared to cemented components. Modular locking mechanisms and wear against screw heads and holes have been implicated in the production of polyethylene particles. Pressure waves and particle access to the pelvis are facilitated by screw holes. The patients in this study had a cementless, modular cup with screw fixation but not in all holes. Therefore factors thought to contribute to osteolysis were present. Methods: 178 consecutive patients (198 hips) underwent primary THA using the EPF cementless cup (Plus Orthopaedics AG, Switzerland). 30 patients (31 hips) had died, 5 hips were revised, 8 were lost to follow up and 9 were unable to attend for radiographs. 126 patients (145 hips) were followed up clinically (Harris Hip Score) and radiographically. Mean follow up was 8.0 years (6.3–9.4). AP, lateral and Judet view radiographs were analysed for osteolysis. Polyethylene wear rates were determined using a validated 2D method (Martell). Results: The mean HHS was 89.0 (44.4–99.9). Osteolysis was seen in 19 hips (13.1%). In only 6 hips (4.1%) osteolysis was evident on the AP radiograph. In 13 hips (9.0%) osteolysis was only seen on lateral or Judet view radiographs. No cups were considered to be loose. Mean linear polyethylene wear rate was 0.10 +/− 0.06 mm/yr. Mean volumetric polyethylene wear rate was 43.2 +/− 28.2 mm. 3. /yr. There was no significant difference between wear rates in hips with osteolysis compared to no osteolysis. Only 1 revision was for aseptic loosening. Discussion: The EPF cup produced good clinical results, and appeared radiologically stable at 8 years. Wear rates are similar to other studies of cementless cups. The osteolysis rate is low given this “worst case scenario” especially considering the increased likelihood of detecting osteolysis with multiple radiographic views

Failure of osseointegration and periprosthetic joint infection (PJI) are the two main reasons of implant failure after total joint replacement (TJR). Nanofiber (NF) implant surface coating represents an alternative local drug eluting device that improves osseointegration and decreases the risk of PJI. The purpose of this study was to investigate the therapeutic efficacies of erythromycin (EM)-loaded coaxial PLGA/PCL-PVA NF coating in a rat S. aureus-infected tibia model.

NF coatings with 100mg and 1000mg EM were prepared. NF without EM was included as positive control. 56 Sprague Dawley rats were divided into 4 groups. A titanium pin (1.0-mm x 8 mm) was placed into the tibia through the intercondylar notch. S. aureus (SA) was introduced by both direct injection of 10 μl broth (1 × 10⁴ CFU) into the medullary cavity and single dip of Ti pins into a similar solution prior to insertion. Rats were sacrificed at 8 and 16 weeks after surgery. The outcome measurements include μCT based quantitative osteolysis evaluation and hard tissue histology.

Results: EM-NF coating (EM100 and EM1000) reduced osteolysis at 8 and 16 weeks, compared to EM0 and negative control. The effective infection control by EM-NFs was further confirmed by hard tissue section analysis. The Bone implant contact (BIC) and bone area fraction Occupancy (BAFO) within 200 µm of the surface of the pins were used to evaluate the osseointegration and new bone formation around the implants. At 16 weeks, the bone implant contact (BIC) of EM 100 (35.08%) was higher than that of negative control (3.43%) and EM0 (0%). The bone area fraction occupancy within 200 µm (BAFO) of EM100 (0.63 mm2) was higher than that of negative control (0.390 mm2) and EM0 (0.0 mm²). The BAFO of EM100 was also higher than that of EM1000 (0.3mm²).

There was much less osteolysis observed with EM100 and EM1000 NF coatings at 16 weeks, as compared to EM0 positive control, p=0.08 and p=0.1, respectively. Osseointegration and periprosthetic bone formation was enhanced by EM-NFs, especially EM100. Data from this pilot study is promising for improving implant surface fabrication strategies.