Heterotopic ossification, osteolysis and implant failure following cervical total disc replacement with the M6-C™ artificial disc.

INTRODUCTION: A recent study reported a 34% mid-term revision rate after M6-C™ cervical total disc replacement (CTDR) for wear-related osteolysis. Here, we aim to investigate the prevalence, risk factors, and radiographic characteristics of periprosthetic bony changes and implant failure of the M6-C™ artificial disc. METHODS: We retrospectively analysed radiographic (conventional X-ray, CT scan) and clinical outcomes (EQ-5D-5L, Neck Disability Index (NDI), and Visual Analog Scale (VAS) for neck and arm pain) data collected during routine follow-up of patients who underwent CTDR with the M6-C™ between 2011 and 2015. RESULTS: In total, 85 patients underwent CTDR with the M6-C™. Follow-up data were available for 43 patients (54% female, mean age 44 years) with 50 implants and a mean follow-up of 8.1 years (6.5-11 years). Implant failure with the presence of severe osteolysis was identified in 5 (12%) patients who were all male (p = 0.016) and implanted at the C5/6 level (p = 0.11). All failed implants required revision surgery. The overall prevalence of osteolysis was 44% (22/50 implants) and 34% (17/50 implants) for significant heterotopic ossification. Patients with high-grade osteolysis showed higher VAS arm pain (p = 0.05) and lower EQ-5D-VAS health VAS (p = 0.03). CONCLUSION: We report a lower reoperation rate for failed M6-C™ implants than previously published, but confirmed that osteolysis and heterotopic ossification are common following CTDR with the M6-C™ and may be asymptomatic. Therefore, we strongly recommend ongoing clinical and radiographic monitoring after CTDR with the M6-C™, particularly for male patients implanted at the C5/6 level.

Factors affecting stress shielding and osteolysis after reverse shoulder arthroplasty: A multicenter study in a Japanese population.

BACKGROUND: Stress shielding and osteolysis around the humeral stem after reverse shoulder arthroplasty causes loosening and periprosthetic fractures and reduces bone stock during revision surgery. In Japanese patients, who have relatively small bodies, different characteristics may exist regarding the occurrence of these changes compared with the characteristics of Westerners, who have relatively larger frames. The purpose of this multicenter study was to investigate the incidence and clarify the predictors of stress shielding and osteolysis in Japanese individuals who underwent reverse shoulder arthroplasty. METHODS: The occurrence of stress shielding and osteolysis was investigated in 135 shoulders that had undergone reverse shoulder arthroplasty at least 2 years prior in five Japanese hospitals. During post-surgical follow-up, which was conducted every 3 months, the locations of the stress shielding occurrences, such as cortical thinning and osteopenia (which primarily occurred in zones 1, 2, and 7, where 1 is the greater tuberosity and 7 is the calcar part), spot weld, and condensation lines, were recorded. Cases without any abnormal findings on radiographs obtained up to ≥2 years after surgery were regarded as having no abnormalities. Finally, the predictors of cortical thinning and proximal humeral osteolysis were assessed using univariate and multivariate regression analyses. RESULTS: Cortical thinning and osteopenia occurred in 68 shoulders, a condensation line occurred in 37 shoulders, and spot weld occurred in 23 shoulders. In particular, greater tuberosity and calcar osteolysis occurred in 40 and 47 shoulders, respectively. Long stem, cementless stem, and a larger proximal filling ratio were independent predictors of cortical thinning and osteopenia, whereas a cementless stem, larger metaphysis diameter, and a larger proximal filling ratio were associated with proximal humeral osteolysis. CONCLUSIONS: The predictors of stress shielding and osteolysis included the use of long stems, cementless stems, larger proximal filling ratios, and larger metaphysis diameters. LEVEL OF EVIDENCE: retrospective comparative study (Level III).

The ceramic coated implant (CCI). Evolution total ankle replacements: a retrospective analysis of 40 ankles with 8 years follow-up.

Diminutive data is available on the outcome of several previously used total ankle replacement implants. The purpose of this study was to investigate the medium-term functional and radiological outcome and implant survival of the CCI Evolution implant. Consecutive series of 40 ankles operated in our hospital with primary TAR using the CCI Evolution implant in 2010-2013 were available for follow-up. The prospective clinical and radiographic data including the Kofoed score, subjective satisfaction and standard radiographs were collected preoperatively and at fixed time-points postoperatively. A CT was obtained in cases where osteolysis or loosening were suspected. The improvement of the Kofoed score and subjective satisfaction were statistically significant (p<0.0001). The implant survival was 97% (95% confidence interval (CI) 81%-100 %) at 5 years, and 81 % (95% confidence interval (CI) 60 %-92%) at 8 years. There were altogether 25 (64%) complications. Overall revision rate was 28% and failure rate 13%. The CCI implant outcome was not acceptable. The malposition of prosthetic components, subsidence, and peri-implant osteolysis were recorded often. Although the patient reported outcome measures improved, mostly due to positive changes in pain severity, overall revision and failure rates were high and comparable with previous findings of the CCI implant.

Outcomes After Revision Total Knee Arthroplasty From a Specific, Now-Recalled Implant System.

BACKGROUND: A specific total knee arthroplasty (TKA) implant system was recently recalled for high incidence of early polymeric wear and osteolysis. We analyzed the early outcomes of aseptic revision with these implants. METHODS: We identified 202 aseptic revision TKAs of this implant system performed at a single institution between 2010 and 2020. Revision indications included aseptic loosening (n = 120), instability (n = 55), and polymeric wear/osteolysis (n = 27). Components were revised in 145 cases (72%) and isolated polyethylene insert exchange occurred in 57 cases (28%). Kaplan-Meier and Cox proportional hazards analyses were used to determine survivorship free from all-cause rerevision and rerevision risk factors. RESULTS: At 2 and 5 years, survivorship free from all-cause rerevision was 89 and 76% in the polyethylene exchange cohort versus 92 and 84% in the component revision cohort (P = .5). At 2 and 5 years, survivorship in revision with components from the same manufacturer was 89 and 80% compared to 95 and 86% in revision with components from a different manufacturer (P = .2). Among re-revisions (n = 30), cones (37%), sleeves (7%), hinge/distal femoral replacement implants were frequently used (13%). Men had increased risk for rerevision (hazard ratio = 2.3, P = .04). CONCLUSION: In this series of aseptic revision TKAs performed on a now-recalled implant system, survivorship free from rerevision was lower than expected when components from the same manufacturer were utilized, but comparable to contemporary reports when both the components were revised with an alternative implant system. Metaphyseal fixation with cones and sleeves as well as highly constrained implants was frequently utilized at time of rerevision TKA. LEVEL OF EVIDENCE: Level IV.

Ten to 13-Year Results of Delta Ceramic-on-Ceramic Total Hip Arthroplasty in Patients Less Than 30 Years Old.

BACKGROUND: We previously reported mid-term results of total hip arthroplasty (THA) using Delta ceramic-on-ceramic (CoC) bearings in 72 patients (86 hips) who were <30 years old. Noise was noted in 8 (9.3%) of the hips, no osteolysis or loosening was detected, and no patient required reoperation. The purpose of this study was to assess clinical and radiographic outcomes, complications, and survivorship at >10 years after THA using Delta CoC bearings in patients who were <30 years old. METHODS: Cementless THA with a Delta CoC bearing was performed between March 2008 and January 2012 in 91 hips of 76 patients who were <30 years old. Eighty-five hips in 71 patients (44 men and 27 women) with a mean age of 25.9 years (range, 16 to 29 years) at surgery were followed for a mean of 10.9 years (range, 10 to 13 years). RESULTS: No ceramic bearings fractured. The incidence of squeaking increased to 5.9% (5 of 85), but the squeaking was not reproducible within individual patients. Periprosthetic osteolysis developed in 3 hips (3 patients): around the stem in 2 and around the metal shell in 1. The stem in 1 hip underwent revision because of a Vancouver type-B2 periprosthetic femoral fracture. One patient with systemic lupus erythematosus underwent irrigation and debridement for periprosthetic joint infection. Survivorship free of reoperation for any reason was 92.4% (95% confidence interval, 82.4% to 100%) at 13 years. CONCLUSIONS: The long-term results and survivorship of Delta CoC THA in patients <30 years old were favorable. LEVEL OF EVIDENCE: Therapeutic Level II . See Instructions for Authors for a complete description of levels of evidence.

Wear rate and osteolysis in two types of second-generation annealed highly cross-linked polyethylene in total hip arthroplasty: A retrospective comparative study with a minimum of five years.

BACKGROUND: As no previous study has directly compared the linear wear rate in two types of second-generation annealed highly cross-linked polyethylene, we performed a retrospective study with a minimum of 5-year follow-up to assess primary arthroplasties in the (1) wear rates and (2) incidence of osteolysis of the two types of HXLPE. HYPOTHESIS: There was no significant difference in the linear wear rate and the incidence of osteolysis between the two types of second-generation annealed highly cross-linked polyethylene. PATIENTS AND METHODS: In this single-center study, we reviewed 257 cases of primary cementless total hip arthroplasties between 2011 and 2015, which were performed with 32mm delta ceramic on second-generation annealed highly cross-linked polyethylene (X3 and E1 were used in 105 and 103 cases, respectively.). The mean wear rate was evaluated using a computer-assisted method, and the incidence of osteolysis was evaluated based on the appearance of a localized area with loss of trabecular bone or cortical erosion adjacent to the implants during the latest follow-up. RESULTS: In total, we evaluated 208 cases, followed postoperatively for over 5 years (mean, 6.1 years, range: 5.0-8.0). There were no significant differences between the two groups with respect to age (list in order of Group X, Group E, p value) (61.2±12.3, 62.7±12.1, p=0.36), sex (ratio of male: 17.1%, 14.6%, p=0.61), body mass index (22.9±3.7, 22.8±4.0, p=0.91), pre- (49.9±14.8, 48.5±13.8, p=0.49) and post-operative (91.3±9.1, 92.7±7.0, p=0.23) Japanese Orthopaedic Association Hip Score, cup size (50.8±3.0, 50.9±2.2, p=0.70), cup inclination (38.7±4.8, 37.6±4.8, p=0.10), and cup anteversion (18.7±6.9, 18.5±7.6, p=0.80). The mean linear wear rates of the X3 and E1 groups were 0.057±0.039 (range: 0-0.16) and 0.054±0.037mm/year (range: 0-0.15), respectively (p=0.61). No osteolysis was found on the final plain radiographs in both groups. DISCUSSION: This study revealed that both types of highly cross-linked polyethylene have excellent linear wear rates and were equally safe to use. However, the difference between the two materials in terms of the long-term wear rate should be further validated. LEVEL OF EVIDENCE: III; retrospective case control study.

Periprosthetic Osteolysis as a Risk Factor for Revision After Total Ankle Arthroplasty: A Single-Center Experience of 250 Consecutive Cases.

BACKGROUND: Periprosthetic osteolysis after total ankle arthroplasty (TAA) is a challenging problem. This study aimed to evaluate the prevalence of and predisposing factors for osteolysis and its effects on clinical outcomes. METHODS: We enrolled 236 patients (250 ankles) who underwent primary TAA using a mobile-bearing HINTEGRA prosthesis, with a mean follow-up of 83.5 months (range, 36 to 182 months), and subsequently divided them into 2 groups: the osteolysis group (79 ankles) and non-osteolysis group (171 ankles). Clinical and radiographic outcomes were compared between the 2 groups, and a bivariable logistic regression analysis was performed to identify predisposing factors for the development of osteolysis. RESULTS: In the osteolysis group (31.6% of the 250 ankles), the mean time of detection was 28.8 months postoperatively. Forty of these ankles were closely monitored without surgical treatment. Another 29 ankles underwent bone grafting and exchange of the polyethylene inlay, and the remaining 10 ankles underwent revision TAA or arthrodesis. All clinical outcome variables were significantly lower in patients with osteolysis, compared with those without osteolysis, at the final follow-up (p < 0.05). In the investigation of predisposing factors, only rheumatoid arthritis was identified as having a significant association with an increased prevalence of osteolysis (p = 0.030). CONCLUSIONS: This study demonstrated that the prevalence of periprosthetic osteolysis after TAA was considerable and that the development of osteolysis negatively affected the clinical outcome. Therefore, the prevention and appropriate treatment of osteolysis are crucial for the satisfactory long-term survival of TAA. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Long-Term Wear-Related Complications of Cross-Linked Versus Conventional Polyethylene After Total Hip Arthroplasty: A Meta-Analysis.

BACKGROUND: Highly cross-linked polyethylene (HXLPE) liners have been developed to address the wear-related problems associated with conventional polyethylene (CPE) such as osteolysis or aseptic loosening in total hip arthroplasty (THA). In this systematic meta-analysis, we compared the long-term efficacy in preventing radiological osteolysis and revision surgery between HXLPE and CPE. METHODS: We included 14 studies that compared HXLPE and CPE reporting the incidence of wear-related complications with a minimum follow-up of 10 years. We investigated 5 wear-related complications: osteolysis, excessive wear, linear wear rate, revision surgery due to wear, and progress of osteolysis/aseptic loosening. We conducted a pair-wise meta-analysis to estimate odds ratio (OR) and a proportional meta-analysis to estimate the incidence of each complication. RESULTS: Among 1,175 THAs, 220 osteolysis and 78 wear-related revisions were detected. The use of HXLPE reduced the risk of overall osteolysis (OR 0.30; P = .001), excessive wear (OR 0.10; P < .001), linear wear rate (weighted mean difference 0.09; P < .001), the risk of overall wear-related revisions (OR 0.06; P < .001), and revisions due to aseptic loosening (OR 0.23; P = .015). As per the proportional meta-analysis, the pooled prevalence of osteolysis, excessive wear, and the overall wear-related revision rate were 14%, 8%, and 3% in HXLPE and 25%, 33%, and 20% in CPE, respectively. CONCLUSION: The current evidence shows that HXLPE dramatically reduced the rate of osteolysis and wear-related revision surgery. However, as polyethylene wear and osteolysis still lead to revision surgery, ongoing clinical and retrieval studies are required to analyze long-term outcomes.

Long-Term (up to 38 Years) Failure Modes of Total Hip Arthroplasty in Adult Patients Who Had Childhood Infection of Hip.

BACKGROUND: The long-term failure modes of total hip arthroplasty (THA) in adult patients who had childhood infection have not been documented. The purpose of this study is to analyze the longer term clinical and radiographic results, prevalence of osteolysis, and survival rate of THA. METHODS: We reviewed the results of 142 patients (145 hips) (mean age 41.9 years). The age of the patients at the time that the infection was contracted was an average of 7.1 years (range 1-11). The average interval between active infection and THA was 34.5 years. All but 2 hips (1 patient) had a quiescent period of infection of more than 10 years. The average duration of follow-up after THA was 31.5 years (range 25-38). RESULTS: All but 2 hips with more than 10 years of quiescent infection had no recurrence of infection. The remaining 2 hips in the 1 patient with only 7 years of quiescent infection had a recurrence of infection. Seventy-eight of 145 hips (54%) underwent isolated cup revision for loosening, or osteolysis, or dislocation. Thirty (21%) femoral components were revised for aseptic loosening and/or osteolysis. The Kaplan-Meier survivorship curve at 31.5 years showed that the survival rate of the acetabular component was 46% (95% confidence interval 39-74) and that of the femoral component was 79% (95% confidence interval 73-89). CONCLUSION: Contributing factors to the high failure rate of THAs were less than optimal prostheses and poor quality of polyethylene during the time period of this study.

Acromial and humeral head osteolysis following superior capsular reconstruction using autologous tensor fascia lata graft.

BACKGROUND: Graft tear is a critical complication following superior capsular reconstruction (SCR) as it directly links with clinical outcomes. No previous reports have described acromial and humeral head osteolysis following SCR. Acromial and humeral head osteolysis may incidentally occur after SCR using autologous tensor fascia lata graft. This study aimed to demonstrate the incidence of osteolysis following SCR using autologous tensor fascia lata graft and investigate the factors that affect osteolysis. METHODS: This retrospective cohort study included patients who underwent SCR for irreparable rotator cuff tears between June 2014 and June 2019. The patients were divided into 2 groups-those with no osteolysis and those with osteolysis-and were compared. For subanalysis, patients in the osteolysis group were further divided into 3 groups according to the location of the osteolysis-acromial osteolysis, humeral head osteolysis, and acromial and humeral head osteolysis-to clarify the factors determining the location of osteolyses. The shoulder range of motion was evaluated preoperatively and 24 months postoperatively. Additionally, the following items were evaluated: condition of the subscapularis tendon, Hamada classification (grade 2 or 3), critical shoulder angle, acromiohumeral distance measured preoperatively and 24 months postoperatively, graft size, and graft thickness. In addition, the graft condition was evaluated using magnetic resonance imaging 12 months postoperatively. RESULTS: In total, 57 patients were enrolled and followed up for a minimum of 2 years (follow-up rate, 92% [57 of 62 cases]). Overall, the incidence of osteolysis following SCR was 35.1% (20 of 57 cases; acromial osteolysis in 7, humeral head osteolysis in 3, and acromial and humeral head osteolysis in 10). Compared with the group with no osteolysis, the osteolysis group had no inferior clinical outcomes or higher graft tear rates. The proportions of Hamada grade 3 (P = .041) and involvement of the subscapularis tendon (P = .020) were significantly higher in the osteolysis group. The relative risks of subscapularis involvement and Hamada grade 3 for osteolysis were 2.9 and 5.1, respectively. In the subanalysis, the factors determining the location of the osteolysis could not be clarified. CONCLUSIONS: This study suggested that the progression of the Hamada classification and condition of the subscapularis tendon affect the occurrence of osteolyses. However, these osteolyses were not associated with clinical outcomes, including graft tear rate and shoulder range of motion.

The use of acetabular screws in total hip arthroplasty and its influence on wear and periacetabular osteolysis in the long-term follow-up.

PURPOSE: The cementless implantation of hip replacement cups may be performed with and without the additional use of acetabular screws. If the surgeon uses screws or not depends on variable factors. In general, the use of screws is intended to increase the primary stability of the cup. Whether screws increase the initial stability of the cup construct, or even reduce it in part, is the subject of considerable debate in the literature. It is also unclear whether the additional screws lead to increased wear or increased periacetabular osteolysis over the long-term course. METHODS: Two hundred eleven patients from a previous study with a minimum follow-up of 10.7 years were included. Of these, 68 patients with 82 total hip arthroplasties (THA) were given clinical and radiological follow-up examinations. Of these, 52 had been fitted without screws and 30 with screws. On the basis of radiographs, annual wear and osteolysis were quantified. The clinical results were recorded by means of VAS, HHS, and WOMAC scores. RESULTS: Significantly more periacetabular osteolysis was found if additive acetabular screws had been used. No difference was found in relation to the volumetric wear per year. Likewise, no difference was found with regard to the clinical scores. CONCLUSIONS: The use of additive acetabular screws leads to increased osteolysis in the periacetabular bone stock. Insofar as the primary stability of the cementless cup construct allows it, no additional acetabular screws should be used.

Rapidly Destructive Hip Disease Following Intra-Articular Corticosteroid Injection of the Hip.

BACKGROUND: While recent reports have suggested that hip corticosteroid injections can hasten joint degeneration, there are few published data on the topic. The purpose of the present study was to evaluate for an association between corticosteroid injection and rapidly destructive hip disease (RDHD) and to determine the rate of, and risk factors for, occurrence. METHODS: This study was conducted in 2 parts. First, to assess for a potential association between hip corticosteroid injection and RDHD, a case-control analysis was performed. Patients who developed RDHD between 2013 and 2016 served as cases, whereas those who underwent total hip arthroplasty for diagnoses other than RDHD during the same period served as controls, and the exposure of interest was prior intra-articular hip corticosteroid injection. Second, in a retrospective cohort analysis, we analyzed all patients who received a fluoroscopically guided intra-articular hip corticosteroid injection at our institution from 2013 to 2016. The rate of post-injection RDHD was determined, and logistic regression was used to identify risk factors for occurrence. RESULTS: In the case-control analysis, hip corticosteroid injection was associated with the development of RDHD (adjusted odds ratio, 8.56 [95% confidence interval, 3.29 to 22.3], p < 0.0001). There was evidence of a dose-response curve, with the risk of RDHD increasing with injection dosage as well as with the number of injections received. In the retrospective cohort analysis, the rate of post-injection RDHD was 5.4% (37 of 688). Cases of post-injection RDHD were diagnosed at an average of 5.1 months following injection and were characterized by rapidly progressive joint-space narrowing, osteolysis, and collapse of the femoral head. CONCLUSIONS: This study documents an association between hip corticosteroid injection and RDHD. While the risk of RDHD following a single low-dose (≤40 mg) triamcinolone injection is low, the risk is higher following high-dose (≥80 mg) injection and multiple injections. These findings provide information that can be used to counsel patients about the risks associated with this common procedure. In addition, caution should be taken with intra-articular hip injections utilizing ≥80 mg of corticosteroid and multiple injections. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Osteolysis at the insertion of L'Episcopo tendon transfer: Incidence and clinical impact.

INTRODUCTION: During a L'Episcopo transfer procedure, the tendons of the latissimus dorsi and teres major are reinserted on the posterolateral side of the humeral shaft to restore active external rotation. The aim of this study was to monitor the radiological changes at the insertion point of this transfer and to evaluate its impact on the clinical outcomes. MATERIALS AND METHODS: In this retrospective, single-center study, 13 patients (mean age 56 years; 19-84) were reviewed after a minimum follow-up of 2 years. The L'Episcopo transfer was done either alone (n=2) or in combination with reverse shoulder arthroplasty (n=11). The same transfer technique was used in both instances, with reattachment by transosseous sutures. The clinical assessment consisted of the Constant score (CS), the Activities of Daily Living Requiring Active External Rotation (ADLER) score and the Subjective Shoulder Value (SSV). Radiographs were used to look for signs of osteolysis of the cortical bone in the tendon transfer areas and classified as grade 1 (minor erosion), grade 2 (moderate erosion) and grade 3 (major erosion). RESULTS: At a mean follow-up of 37 months (24-72), the mean CS was 60 points (32-75), the ADLER was 21 points (15-30) and the SSV was 77% (10-95). In the radiographic analysis, 10/13 patients had osteolysis visible in the transfer area: 2 were grade 1 (15%), 1 was grade 2 (8%), 7 were grade 3 (54%). There was no statistical correlation between the presence of osteolysis and the clinical outcomes. Nevertheless, external rotation with elbow at side and forward flexion were better in the patients who had osteolysis≥grade 2. CONCLUSION: The L'Episcopo transfer is associated with frequent osteolysis of the humeral cortex where the transfer is attached, even though the transfer appears effective. Long-term follow-up will be needed to evaluate the impact of this osteolysis on the stability of any shoulder arthroplasty implants. LEVEL OF EVIDENCE: IV; retrospective study.

Relationship Between Glenoid Component Shift and Osteolysis After Anatomic Total Shoulder Arthroplasty: Three-Dimensional Computed Tomography Analysis.

BACKGROUND: The purpose of this study was to evaluate glenoid component position and radiolucency following anatomic total shoulder arthroplasty (TSA) using sequential 3-dimensional computed tomography (3D CT) analysis. METHODS: In a series of 152 patients (42 Walch A1, 16 A2, 7 B1, 49 B2, 29 B3, 3 C1, 3 C2, and 3 D glenoids) undergoing anatomic TSA with a polyethylene glenoid component, sequential 3D CT analysis was performed preoperatively (CT1), early postoperatively (CT2), and at a minimum 2-year follow-up (CT3). Glenoid component shift was defined as a change in component version or inclination of ≥3° from CT2 to CT3. Glenoid component central anchor peg osteolysis (CPO) was assessed at CT3. Factors associated with glenoid component shift and CPO were evaluated. RESULTS: Glenoid component shift occurred from CT2 to CT3 in 78 (51%) of the 152 patients. CPO was seen at CT3 in 19 (13%) of the 152 patients, including 15 (19%) of the 78 with component shift. Walch B2 glenoids with a standard component and glenoids with higher preoperative retroversion were associated with a higher rate of shift, but not of CPO. B3 glenoids with an augmented component and glenoids with greater preoperative joint-line medialization were associated with CPO, but not with shift. More glenoid component joint-line medialization from CT2 to CT3 was associated with higher rates of shift and CPO. A greater absolute change in glenoid component inclination from CT2 to CT3 and a combined absolute glenoid component version and inclination change from CT2 to CT3 were associated with CPO. Neither glenoid component shift nor CPO was associated with worse clinical outcomes. CONCLUSIONS: Postoperative 3D CT analysis demonstrated that glenoid component shift commonly occurs following anatomic TSA, with increased inclination the most common direction. Most (81%) of the patients with glenoid component shift did not develop CPO. Longer follow-up is needed to determine the relationships of glenoid component shift and CPO with loosening over time. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Minimum 15-year results of metasul 28-mm metal-on-metal total hip arthroplasty in patients younger than 50 years of age.

BACKGROUND: Some propitious mid- and long-term studies had been reported for MoM bearings; however, most studies have addressed specific patient groups rather than younger, active patients, who probably represent the most suitable population for investigations on wear and osteolysis. The purpose of this study to evaluate the long-term results of second-generation metal-on-metal cementless total hip arthroplasty (THA) in patients aged <50 years. METHODS: From December 1997 to January 2004, primary THA using a metal-on-metal bearing cementless implant was performed in 63 patients (72 hips) aged <50 years. The mean follow-up duration was 18.6 (range, 15.9-22.1) years, and the mean age at initial operation was 39 (range, 22-49) years. Clinical results, complications, survivorship, osteolysis, and aseptic loosening were evaluated. RESULTS: The mean Harris hip score and Western Ontario and McMaster Universities Arthritis Index scores were improved from 57.8 (range, 28-69) points and 73.4 (range, 63-94) points preoperatively to 91.7 (range, 80-100) points and 25.5 points (range, 17-38) points, respectively, at the last follow-up. Osteolysis lesions were found in 12 hips (acetabulum, 6 and femur, 6). The notching occurred on the femoral stem neck occurred in 12 hips. The mean serum cobalt and chromium concentrations were 2.3 (range, 0.2-10.6) µg/L and 1.7 (range, 0.4-8.1) µg/L, respectively, at a mean follow-up of 12.7 years in 32 patients (50.1%). The Kaplan-Meier survivorship curve analysis with revision for any reason as the endpoint revealed that 93.1% survived at 18.6 years' follow-up. CONCLUSIONS: Second-generation metal-on-metal cementless THA was found to produce satisfactory clinical and radiographic results with a low revision rate for osteolysis and aseptic loosening in patients aged less than 50 years.

Incidence of Osteolysis and Aseptic Loosening Following Metal-on-Highly Cross-Linked Polyethylene Hip Arthroplasty: A Systematic Review of Studies with Up to 15-Year Follow-up.

BACKGROUND: This study compared the incidence of osteolysis, aseptic loosening, and revision following use of highly cross-linked polyethylene (HXLPE) or conventional polyethylene (CPE) at medium to long-term (>5 to 15 years) follow-up in primary total hip arthroplasty (THA). Incidences were quantified and compared with regard to age and method of implant fixation. METHODS: Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, 12 randomized controlled trials and 18 cohort studies were investigated for evidence-based outcomes following HXPLE and CPE use in 2,539 hips over a 5 to 15-year follow-up. RESULTS: Lower rates of osteolysis, aseptic loosening, and implant revision were reported following use of HXLPE liners. Osteolysis was reduced from 25.4% with CPE to 4.05% with HXLPE in young patients, and from 29.7% to 6.6% in the older patient cohort. Similarities in osteolysis rates were observed when cemented (24.9% for CPE and 6.5% for HXLPE) and uncemented components (32.8% for CPE and 7.1% for HXLPE) were compared. No clear advantage in the type of HXLPE used was observed. CONCLUSIONS: Over a follow-up period of up to 15 years, when compared with CPE, use of HXLPE liners reduced the incidence of osteolysis, aseptic loosening, and implant revision, regardless of the fixation method and including in younger and potentially more active patients. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Wear and osteolysis outcomes for highly cross-linked polyethylene in primary total hip arthroplasty compared with conventional polyethylene: a 15- to 18-year single-centre follow-up study.

BACKGROUND: Although highly positive results for wear reduction of highly cross-linked polyethylene (HXLPE) have been reported around the 10-year follow-up, the long-term result related to reoperation and wear-related survival is still an issue. Therefore, this study aimed to compare the follow-up results of a single manufacture's polyethylene liner for >15 years in terms of survival and wear rate. METHODS: This retrospective cohort study included 134 primary total hip arthroplasties (THAs) who were followed up for at least 15 years. The mean age at the time of surgery was 50.7 years (conventional polyethylene [CPE] group = 22; HXLPE group = 112). Linear and volumetric wear rates of polyethylene were measured, and the reoperation rate and radiographic osteolysis were evaluated and Kaplan-Meier survival analysis was performed in both groups. Implant-related complications were also examined. RESULTS: HXLPE group showed a significantly lower wear rate in both linear and volumetric wear. None of the hip radiographs showed evidence of loosening or osteolysis in the HXLPE group. The survival rates at 15- to 18-year follow-up were 90.9% and 95.5% in the CPE and HXLPE groups when all-cause reoperation was the endpoint, and 90.9% and 100.0% when the wear-related reoperation was the endpoint, respectively. Implant-related complications were not different between the 2 groups. CONCLUSIONS: Wear reduction and osteolysis showed a great advantage in HXLPE after a 15-year follow-up. Although the CPE and HXLPE showed excellent survival, wear and osteolysis were more frequent in the CPE; therefore, the high risk of reoperation in the future should be considered.

Outcome and Risk Factors Associated with Failures of Isolated Bearing Exchange for Osteolysis in Well-Fixed Cementless Total Hip Arthroplasty.

BACKGROUND: It is often challenging to decide whether to revise only the bearing or femoral acetabular component in the setting of progressive osteolysis without component loosening in revision total hip arthroplasty (THA). In this study, we aimed to (1) compare the survivorship of isolated bearing exchange and single/both component revision for patients with periprosthetic osteolysis without component loosening, and (2) identify potential risk factors associated with failures of isolated bearing exchange. METHODS: A total of 228 consecutive cases of revision THA for progressive osteolysis without component loosening was evaluated in 2 groups: (1) 124 component revision and (2) 104 isolated bearing exchange. The primary outcome was survival, with failure defined as repeat revision or reoperation for any reason. Patient risk factors, such as demographics and medical comorbidities, were also analyzed. RESULTS: There was no significant difference in survivorship between the component revision group and the bearing exchange group at 10 years (85% vs 82%; P = .89). There was no progression of osteolysis on radiographs at last follow-up for patients with isolated bearing change. Univariate regression modeling demonstrated that renal disease was associated with failure of isolated bearing exchange after revision THA. CONCLUSION: This study demonstrated that isolated bearing exchange is associated with similar outcomes compared with component revision for aseptic osteolysis without loosening, demonstrating that isolated bearing exchange is a viable option for selected patients with osteolysis in the setting of well-fixed THA components. This provides clinically useful information for surgeons in the surgical treatment of THA patients with wear and osteolysis without component loosening.

Arthroscopic remplissage with all-suture anchors causes cystic lesions in the humerus: a volumetric CT study of 55 anchors.

PURPOSE: To evaluate with computed tomography (CT) the incidence of implant-related osteolysis after implantation of two types of all-suture anchors during remplissage for the management of Hill-Sachs lesions in shoulder instability. METHODS: Single-cohort, observational study with a minimum of 12 months follow-up. Twenty-five participants (19 males and 6 females; mean age 37.4 years [SD: 11.6]) with Hill-Sachs lesions requiring remplissage were evaluated with a CT performed a mean of 14.1 [3.74] months after surgery. Fifty-five all-suture anchors (19 2.3 mm Iconix and 36 1.7 mm Suturefix) were used. The volume of the bone defects was measured in the CT. Every anchor was classified into one of four groups: (1) no bone defect. (2) Partial bone defect (bone defects smaller than the drill used for anchor placement). (3) Tunnel enlargement (bone defect larger than the drill volume but smaller than twice that volume). (4) Cystic lesion (bone defect larger twice the drill volume). RESULTS: No bone defect was identified in only two anchors (3.6%, 95% CI 0.4-12.5%). A partial bone defect was found in eight anchors (14.5%, 95% CI 6.5-26.7%). In 35 anchors (63.6%, 95% CI 49.6-76.2%), there was enlargement of the bone defect that was smaller than 200% the size of the drill used. Ten anchors caused bone defects larger than twice the size of the drill used (18.2%, 95% CI 9.1-30.9%). The defect size was a mean of 89 mm3 (SD: 49 mm3, minimum 0 mm3, maximum 230 mm3). CONCLUSION: When using all-suture anchors in arthroscopic remplissage during instability surgery, relevant bone osteolytic defects are common at 1-year-follow-up. Cystic defects larger than twice the volume of the resected bone during implantation develop in one in six anchors and significant tunnel widening will develop in another three out of five anchors. This bone loss effectively increases the size and depth of the Hill-Sachs lesions but does not seem to affect short-term clinical outcomes. LEVEL OF EVIDENCE: Level IV.

Incidence and Characteristics of Osteolysis in HXLPE THA at 16-Year Follow up in Patients 50 Years and Less.

INTRODUCTION: Young patients present a challenge for total hip arthroplasty (THA) survivorship. Highly cross-linked polyethylene (HXLPE) liners have decreased the prevalence of osteolysis; however, concerns exist regarding the biologic activity of wear particles. The purpose of this study was to determine the incidence and characteristics of osteolytic lesions in young HXLPE THA patients at an average 16-year follow up and determine the ability to detect osteolysis. METHODS: We performed a retrospective study involving 22 patients (26 THA) under age 50 at primary THA receiving HXLPE liners coupled with cobalt-chrome (CoCr) femoral heads. Computed tomography (CT) scans were reviewed for osteolysis. Chi-squared analysis was used for categorical variables and unpaired Kruskal-Wallis rank-sum test for continuous variables. Logistic regression was used to compare wear rates between those patients with and without osteolysis. RESULTS: The mean age at surgery was 38.5 years. The mean time from surgery to CT scan was sixteen years (range 14.25-19.5 years). Nine of the 26 THA showed osteolysis. The mean volume of the lesions was 2.8 cm3. Linear (mean 0.008 mm/y) and volumetric (mean 4.5 mm3/year) wear rates were negligible. One-third of osteolytic lesions were visible on radiographs. Logistic regression failed to demonstrate a correlation between wear rates or UCLA activity score and osteolysis. CONCLUSION: We observed osteolysis in 35% of HXLPE THA in young patients at mean 16-year follow up despite zero revisions for wear-related problems and clinically insignificant wear rates. LEVEL OF EVIDENCE: IV.