Cup Fixation Research Articles

Periprosthetic acetabular fractures: classifications, treatment and challenges

Periprosthetic acetabular fractures (PPAF) are fractures of the acetabulum with ahip endoprosthesis in place. They are arare complication, although they are occurring more frequently due to the increase in patients being fitted with total hip arthroplasty (THA) and the long service life of the implants. At present, only asmall amount of scientific literature exists, particularly regarding the surgical treatment of these fracture types.The aim of this paper is to provide an overview of the topic of PPAF with acritical review of the current literature and to present the necessary surgical treatment.An evaluation of the current literature on the topic of PPAF with afocus on the surgical treatment of fractures is carried out.Surgical treatment is technically demanding due to the pelvic ring instability with removal of the bone tension for secure acetabular cup fixation and should lead to the recovery of the biomechanical stability of the pelvis and thus the secure anchoring of the acetabular cup. An interdisciplinary approach requiring both trauma surgery and orthopaedic expertise is certainly recommended, as older and comorbid patients with poor bone quality are particularly frequently affected.The treatment of periprosthetic acetabular fractures, especially in older patients, requires not only the individual expertise of surgeon involved in the operation but also agoal-oriented and consistent interdisciplinary approach by the surgeons involved from the fields of orthopaedics and trauma surgery in view of the patients' frequent comorbidities. By working together, the optimal and individualized operation can be performed for the patient.

LOW RISK OF CUP FIXATION FAILURE AT TEN YEARS USING CONSTRAINED LINER AT THE SAME TIME OF ACETABULAR COMPONENT REVISION

There remains concern with the use of constrained liners (CL) implanted at the time of acetabular cup revision in revision total hip replacement (rTHA). The aim of this study was to determine the implant survival in rTHA when a CL was implanted at the same time as acetabular cup revision.We reviewed our institutional database to identify all consecutive rTHAs where a CL was implanted simultaneously at the time acetabular cup revision from 2001 to 2021. One-hundred and seventy-four revisions (173 patients) were included in the study. Mean follow-up of 8.7 years (range two – 21.7). The most common indications for rTHA were instability (35%), second-stage periprosthetic joint infection (26.4%), and aseptic loosening (17.2%).Kaplan Meier Analysis was used to determine survival with all-cause re-revision and revision for cup aseptic loosening (fixation failure) as the endpoints.A total of 32 (18.3%) patients underwent re-revision at a mean time of 2.9 years (range 0.1 – 14.1). The most common reasons for re-revision were instability (14), periprosthetic joint infection (seven), and loosening of the femoral component (four). Three (1.7%) required re-revision due to aseptic loosening of the acetabular component (fixation failure) at a mean of two years (0.1 – 5.1). Acetabular component survival free from re-revision due to aseptic loosening was 98.9% (95% CI 97.3 – 100) at five-years and 98.1% (95% CI 95.8 – 100) at 10-years. There were no acetabular component fixation failures in modern highly porous shells.CLs implanted at the time acetabular cup revision in rTHA have a 98.1% 10-year survival free from acetabular cup aseptic loosening (fixation failure). There were no cup fixation failures in modern highly porous shells. Thus, when necessary, implanting a CL during revision of an acetabular component with stable screw fixation is safe with an extremely low risk of cup fixation failure.

Midterm Results of Severe Hip Dysplasia after Using a Cementless Acetabular Component with Bulk Bone Graft in Total Hip Arthroplasty: A Minimum Five-Year Follow-Up Study.

In patients with severe hip dysplasia, total hip arthroplasty (THA) using bulk bone graft (BBG) enhances anatomic cup positioning and provides early structural support. This study assesses the mid-term outcomes of THA with BBG in patients with over 50% graft bone coverage. Among 1951 patients who underwent THA between 2003 and 2007, 183 had BBG. After excluding early dropouts and infections, 151 patients remained. They were classified into uncovered (<50% coverage, 79 patients) and covered (>50% coverage, 72 patients) groups. The efficacy of cup fixation was compared between these groups. After ten years, the survival rate for not needing THA revision was 98% in the uncovered group and 100% in the covered group, while the rate for radiographic stability was 93% versus 99%, respectively. Although the cutoff value for the uncovered portion could not be clarified in this study, the mid-term results for 50% to approximately 70% uncovered were comparable to those for 50% or lesser, which have previously been expected to perform well. Recently, biomechanically advantageous bone grafting techniques have been identified, and based on the results of this study, it may be possible to expand the indications for THA with bone grafting for developmental dysplasia of the hip.

Association between cup fixation screw and iliopsoas impingement after total hip arthroplasty

BackgroundIliopsoas impingement after total hip arthroplasty can result not only from acetabular cup but also from cup fixation screw. However, research addressing this screw impingement is scarce, leaving the details undetermined. This study aimed to elucidate the incidence and threshold of symptomatic iliopsoas impingement attributable to protrusion of the cup fixation screw into the iliopsoas muscle and to evaluate its impact on postoperative radiographic imaging findings and patient-reported outcome measures. MethodsA total of 152 hips were included in this study. The symptomatic threshold of screw protrusion was determined using a receiver operating characteristic curve, and patients were divided into low-protrusion and high-protrusion groups using this threshold. The area and Hounsfield Unit values of the iliopsoas muscle on CT and the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire postoperatively were investigated. Findings10 hips (6.5%) were exhibited symptoms of IPI in this series. The threshold for screw protrusion length was identified as 6.4 mm. Patients in the high protrusion group exhibited significantly larger area and lower Hounsfield Unit values of the iliopsoas muscle. In addition, the high protrusion group revealed significantly lower scores (total, pain, movement, mental). Furthermore, subscales scores (pain, movement) in the high protrusion group didn't improve from 3 months to 12 months postoperatively with significance. InterpretationThis study underscores the imperative for surgeons to consider the length of the cup fixation screw. This careful consideration is crucial for mitigating the incidence of postoperative iliopsoas impingement and enhancing total hip arthroplasty outcomes.

Evaluation of bone integrity around the acetabular cup using noninvasive laser resonance frequency analysis.

Resonance frequency analysis (RFA) is valuable for assessing implant status. In a previous investigation, acetabular cup fixation was assessed using laser RFA and the pull-down force was predicted in an in vitro setting. While the pull-down force alone is sufficient for initial fixation evaluation, it is desirable to evaluate the bone strength of the foundation for subsequent fixation. Diminished bone quality causes micromotion, migration, and protracted osseointegration, consequently elevating susceptibility to periprosthetic fractures and failure of ingrained trabecular bone. Limited research exists on the evaluation of bone mineral density (BMD) around the cup using RFA. For in vivo application of laser RFA, we implemented the sweep pulse excitation method and engineered an innovative laser RFA device having low laser energy and small dimensions. We focused on a specific frequency range (2500-4500 Hz), where the peak frequency was presumed to be influenced by foundational density. Quantitative computed tomography with a phantom was employed to assess periprosthetic BMD. Correlation between the resonance frequency within the designated range and the density around the cup was evaluated both in the laboratory and in vivo using the novel laser RFA device. The Kruskal-Wallis test showed robust correlations in both experiments (laboratory study: R = 0.728, p < 0.001; in vivo study: R = 0.619, p < 0.001). Our laser RFA system can assess the quality of bone surrounding the cup. Laser RFA holds promise in predicting the risk of loosening and might aid in the decision-making process for additional fixation through screw insertion.

Acetabular fractures in geriatric patients: epidemiology, pathomechanism, classification and treatment options.

The incidence of geriatric acetabular fractures has shown a sharp increase in the last decades. The majority of patients are male, which is different to other osteoporotic fractures. The typical pathomechanism generally differs from acetabular fractures in young patients regarding both the direction and the amount of force transmission to the acetabulum via the femoral head. Geriatric fractures very frequently involve anterior structures of the acetabulum, while the posterior wall is less frequently involved. The anterior column and posterior hemitransverse (ACPHT) fracture is the most common fracture type. Superomedial dome impactions (gull sign) are a frequent feature in geriatric acetabular fractures as well. Treatment options include nonoperative treatment, internal fixation and arthoplasty. Nonoperative treatment includes rapid mobilisation and full weighbearing under analgesia and is advisable in non- or minimally displaced fractures without subluxation of the hip joint and without positive gull sign. Open reduction and internal fixation of geriatric acetabular fractures leads to good or excellent results, if anatomic reduction is achieved intraoperatively and loss of reduction does not occur postoperatively. Primary arthroplasty of geriatric acetabular fractures is a treatment option, which does not require anatomic reduction, allows for immediate postoperative full weightbearing and obviates several complications, which are associated with internal fixation. The major issue is the fixation of the acetabular cup in the fractured bone. Primary cups, reinforcement rings or a combination of arthroplasty and internal fixation may be applied depending on the acetabular fracture type.

Dual Mobility Cup Fixation Augmented by Pegs and Screws for Total Hip Arthroplasty in a Geriatric Population with Osteoporosis: Short- and Medium-Term Results of a Retrospective Series of 45 Patients

Introduction: Total Hip Arthroplasty (THA) requires stable primary fixation of the acetabular implant. The main objective of this study was to evaluate, in a geriatric population, the radiological results and the medium-term survival of a Dual Mobility Cup (DMC) with hydroxyapatite coating and tripod fixation augmented by 2 pegs and a screw. Hypothesis: In a geriatric population prone to osteoporosis, this type of implant offers medium-term survival &gt;95% and a complication rate similar to the data from the literature. Methods: This single-center retrospective study included 45 patients (30 women and 15 men) with a mean age of 79.3±5.4 years. Patients included were over 70 years old, with this type of implant for any indication for a first-line THA (30 cases) or revision (15 cases), the initial indication was a proximal femoral fracture in 71% of cases. For each patient, X-rays, clinical scores (Oxford Hip Score, EQ-5D-5L, Parker score) and implant survival were evaluated at the last follow-up. Results: The mean radiological follow-up was 25.4±16 months. Clinical follow-up was 39.9±14 months for 30 patients. For 15 patients (4 lost to follow-up and 11 deceased), clinical data were not available. For 3 patients, periprosthetic osteolysis was observed in zones I and II, as per the DeLee and Charnley system. The Oxford Hip Score was 41.1±8.8 (range: 16-48). The mean VAS was 0.9±1.6 and the mean EQ-5D-5L was 0.6±0.3. Discussion: The use of DMC with fixation augmented by pegs and screws is safe and effective in the short and medium term for THA in a geriatric population.

Minimum 10-Year Survivorship of Uncemented Acetabular Reconstruction With Bulk Femoral Head Autografting in Crowe Type IV Developmental Hip Dysplasia

BackgroundIn total hip arthroplasty (THA) for severe dislocations such as Crowe type IV developmental dysplasia of the hip (DDH), sufficient bone volume for stable fixation of the acetabular component can be achieved by placing a reinforcing bone graft prepared from the resected femoral head into the deficient acetabulum. The purpose of the current study was to examine the long-term survivorship of uncemented THA in conjunction with a bulk femoral head autograft in patients who have Crowe type IV DDH. MethodsA total of 35 patients (42 hips) who have Crowe type IV DDH and underwent THA using uncemented cup fixation with bulk femoral head autografting were followed up for a mean period of 15.0 years (range, 10.0 to 20.0) postoperatively. Anteroposterior pelvic radiographs were used for measurements such as the horizontal coverage of the grafted bone and the center-edge angle. Kaplan–Meier survivorship analyses were performed with revision of the acetabular component as the endpoint. ResultsThe Kaplan–Meier analysis indicated 15-year survival rates of 90.4%. The mean horizontal coverage of grafted bone was 46.1% (range, 23.7 to 66.0), and there were 16 cases with horizontal coverage of ≥ 50%. There was no difference in the appearance of a thin (< 1 mm) radiolucency line around the cup between cases with < 50% versus ≥ 50% of the horizontal coverage of grafted bone (4 versus 2 hips; P = .446). Trabecular bridging and remodeling were seen in all cases after mean periods of 4.1 and 9.0 months postoperatively, respectively. Trabecular reorientation was seen in 41 of 42 hips (97.6%) at a mean follow-up of 19.9 months. ConclusionsAcetabular reconstruction with femoral bulk bone grafting for Crowe type IV DDH resulted in high survival rates and was a good method to restore bone stock and obtain long-term fixation.

Influence of obesity on load-transfer mechanism, contact mechanics, and longevity of cemented acetabular cup

ObjectiveThis investigation aimed to assess the impact of obesity on the load-transfer mechanism, longevity, and contact mechanics of cemented acetabular cups. MethodsThree obesity scenarios were considered: obese case-I (100–110 kg), obese case-II (120–130 kg), and obese case-III (140–150 kg). Utilising six finite element models, the effects of different bodyweights on load transfer, contact mechanics, and cup longevity during normal walking conditions were assessed. Muscle forces and hip joint reaction forces were adjusted and linearly calibrated based on obesity cases. ResultsElevated stresses in cortical and cancellous bones, as well as the cement mantle, were observed in obese cases, suggesting a heightened risk of loosening and failure of the cemented fixation of the acetabular cup. Additionally, increased contact pressure and micromotion between articulating surfaces were noted in obese individuals, with a gradual escalation from obese case-I to obese case-III. ConclusionsThese findings highlight the significant negative impact of obesity on the performance of cemented acetabular cups, emphasizing the importance of considering bodyweight variations in the design and assessment of orthopaedic implants for optimal functionality and durability.

Differences in acoustic parameters of hammering sounds between successful and unsuccessful initial cementless cup press-fit fixation in total hip arthroplasty.

It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation.

Implant fixation of primary total hip arthroplasty using a cementless cup for osteoarthritis secondary to developmental dysplasia of the hip: A prospective multicenter study in Japan

PurposeThis prospective multicenter study investigated the implant fixation of a cementless cup in primary total hip arthroplasty (THA) for osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH) in Japanese patients. MethodsTen hospitals in Japan were enrolled in this study. The cohort comprised 267 hips in 228 Japanese patients who underwent primary THA for OA secondary to DDH. An acetabular cup with advanced in-growth, GRIPTION™ coating, was used in all patients. Mean age at surgery was 66.9 (range 45–89) years, and 201 patients (239 hips) were female. Of these patients, 89.1 ​% (238/267) was Crowe group I. Radiolucent lines around the cup, osteolysis, cup migration, grafted bone status, and clinical scores were evaluated preoperatively and at 6 months, 1 year, and 2 years postoperatively. Adverse events were evaluated throughout the study. Implant survivorship was assessed using the Kaplan–Meier method. ResultsNine hips had radiolucent lines ≥2 ​mm that resolved by 6 months. All cups showed bone in-growth and no cups loosened. At 2 years, the bone grafts had remodeled and incorporated in 68 ​% (43/63) of hips. There were four systemic and five surgical site events, and one procedure-related dislocation. The survivorship with cup revision as the endpoint was 99.6 ​% (95 ​% confidence interval, 97.3–99.9). All clinical scores were improved at 2 years compared with preoperatively (p ​< ​0.01). ConclusionsAn advanced in-growth coated cup showed good fixation without complications in primary THA, even in patients with OA secondary to DDH.

The Validation of Two-Dimensional and Three-Dimensional Radiographic Measurements of Host Bone Coverage in Total Hip Arthroplasty for Hip Dysplasia: A Comparison with Intra-Operative Measurements.

Several methods have been introduced to measure the host bone coverage of the acetabular component after total hip arthroplasty (THA). The aims of this study were (1) to validate two-dimensional- and three-dimensional-based host bone coverage measurements by comparing intra-operative measurements, and (2) to determine the minimum host bone coverage for achieving stable cup fixation after THA in hip dysplasia. The clinical outcomes of each patient were evaluated during their final follow-up period using the Harris Hip score (HHS). The coverage of the host bone was analyzed by comparing 2D-based, 3D-based, and intraoperative assessments. The mean HHS was increased significantly from 60.84 ± 14.21 pre-operatively to 93.13 ± 4.59 (p < 0.0001). The host bone coverage ratio measured intraoperatively was 83.67 ± 3.40%, while the ratio measured by 3D CT reconstruction was 82.72 ± 3.59%. There was a strong positive correlation between the intra-operative host bone coverage and the 3D-based one (r = 0.826, p < 0.0001). It is recommended that 3D-based measurements are used to evaluate the host bone coverage after THA in patients with hip dysplasia. In addition, achieving a minimum host bone coverage of 75% is recommended for the attainment of stable cup fixation.

Anterior column acetabulum fracture fixation with a screw-augmented acetabular cup—a biomechanical feasibility study

BackroundThe beneficial effects of unrestricted postoperative full weight bearing for elderly patients suffering hip fractures have been demonstrated. However, there is still existing disagreement regarding acetabular fractures.The aim of this biomechanical study was to evaluate the initial load bearing capabilities of different fixation constructs of anterior column fractures (ACFs) in osteoporotic bone. MethodsArtificial pelvises with ACFs were assigned to three groups (n = 8) and fixed with either a 7.3 mm partially threaded antegrade cannulated screw (group AASS), an anteriorly placed 3.5 mm plate (group AAPF), or a press-fit acetabular cup with screw augmentation (group AACF). All specimens underwent ramped loading from 20 N preload to 200 N at a rate of 18 N/s, followed by progressively increasing cyclic testing at 2 Hz until failure performed at a rate of 0.05 N/cycle. Relative displacements of the bone fragments were monitored by motion tracking. FindingsInitial stiffness (N/mm) was 118.5 ± 34.3 in group AASS, 100.4 ± 57.5 in group AAPF, and 92.9 ± 44.0 in group AACF, with no significant differences between the groups, p = 0.544. Cycles to failure were significantly higher in groups AACF (8364 ± 2243) and AAPF (7827 ± 2881) compared to group AASS (4440 ± 2063), p ≤ 0.041. InterpretationFrom a biomechanical perspective, the minimally invasive cup fixation with screw augmentation demonstrated comparable stability to plate osteosynthesis of ACFs in osteoporotic bone. The results of the present study do not allow to conclusively answer whether immediate full weight bearing following cup fixation shall be allowed. Given its similar performance to plate osteosynthesis, this remains rather an utopic wish and a more conservative approach deems more reasonable.

The accuracy of an accelerometer-based portable navigation system for total hip arthroplasty using 3D CT measurement in the supine position: a prospective multicenter study

PurposeThis multicenter prospective study aimed to evaluate the accuracy of the cup alignment of an accelerometer-based portable navigation system (AP navigation) for a total hip arthroplasty (THA) in spine position. MethodsThis study prospectively enrolled 324 THAs using supine position in 9 hospitals. An AP navigation was used for cup fixation and the intraoperative navigation data (cup alignment, pelvic tilt, and pelvic rotation) were recorded. Computed tomography (CT) of the pelvis was performed 2 weeks post-operatively and cup alignment was measured on 3D-CT images. ResultThe accuracy (absolute difference in cup alignment between the intraoperative navigation record and postoperative 3D-CT measurements) was 3 ​± ​3° (mean ​± ​standard deviation) for cup inclination and 3 ​± ​3° for cup anteversion. The pelvis tilted anteriorly in 148 hips (46%) and posteriorly in 162 hips (50%), and did not tilt in 14 hips (4%). The pelvis rotated toward the operating side in 179 hips (55%), toward the contralateral side in 112 hips (35%), and did not rotate in 33 hips (10%). Multiple regression analysis showed that the patients’ characteristics (sex, body mass index, diagnosis, Crowe classification, laterality, intraoperative pelvic tilt, intraoperative pelvic rotation, and cup size) and the surgical factors (approach, preparation time, number of screws, and institution) did not affect the accuracy of the navigation system. ConclusionsThis is the first prospective multicenter study of this navigation system. The accuracy was not affected by patient characteristics, surgical factors, or substantial pelvic movement during cup fixation.

ISCHIAL SCREW FIXATION CAN PREVENT CUP MIGRATION IN 3D-PRINTED CUSTOM ACETABULAR COMPONENTS FOR COMPLEX HIP RECONSTRUCTION

Custom acetabular components have become an established method of treating massive acetabular bone defects in hip arthroplasty. Complication rates, however, remain high and migration of the cup is still reported. Ischial screw fixation (IF) has been demonstrated to improve mechanical stability for non-custom, revision arthroplasty cup fixation. We hypothesise that ischial fixation through the flange of a custom acetabular component aids in anti-rotational stability and prevention of cup migration.Electronic patient records were used to identify a consecutive series of 49 custom implants in 46 patients from 2016 to 2022 in a unit specializing in complex joint reconstruction. IF was defined as a minimum of one screw inserted into the ischium passing through a hole in a flange on the custom cup.The mean follow-up time was 30 months. IF was used in 36 cups. There was no IF in 13 cups. No difference was found between groups in age (68.9 vs. 66.3, P = 0.48), BMI (32.3 vs. 28.2, P = 0.11) or number of consecutively implanted cups (3.2 vs. 3.6, P = 0.43). Aseptic loosening with massive bone loss was the primary indication for revision. There existed no difference in Paprosky grade between the groups (P = 0.1). 14.2% of hips underwent revision and 22.4% had at least one dislocation event.No ischial fixation was associated with a higher risk of cup migration (6/13 vs. 2/36, X2 = 11.5, P = 0.0007). Cup migration was associated with an increased risk for all cause revision (4/8 vs. 3/38, X2 = 9.96, P = 0.0016, but not with dislocation (3/8 vs. 8/41, X2 = 1.2, P = 0.26).The results suggest that failure to achieve adequate ischial fixation, with screws passing through the flange of the custom component into the ischium, increases the risk of cup migration, which, in turn, is a risk factor for revision.

Simulated full weight bearing following posterior column acetabular fracture fixation: a biomechanical comparability study

PurposeThe incidence of acetabular fractures (AFs) is increasing in all industrial nations, with posterior column fractures (PCFs) accounting for 18.5–22% of these cases. Treating displaced AFs in elderly patients is a known challenge. The optimal surgical strategy implementing open reduction and internal fixation (ORIF), total hip arthroplasty (THA), or percutaneous screw fixation (SF), remains debated. Additionally, with either of these treatment methods, the post-surgical weight bearing protocols are also ambiguous. The aim of this biomechanical study was to evaluate construct stiffness and failure load following a PCF fixation with either standard plate osteosynthesis, SF, or using a screwable cup for THA under full weight bearing conditions.MethodsTwelve composite osteoporotic pelvises were used. A PCF according to the Letournel Classification was created in 24 hemi-pelvis constructs stratified into three groups (n = 8) as follows: (i) posterior column fracture with plate fixation (PCPF); (ii) posterior column fracture with SF (PCSF); (iii) posterior column fracture with screwable cup fixation (PCSC). All specimens were biomechanically tested under progressively increasing cyclic loading until failure, with monitoring of the interfragmentary movements via motion tracking.ResultsInitial construct stiffness (N/mm) was 154.8 ± 68.3 for PCPF, 107.3 ± 41.0 for PCSF, and 133.3 ± 27.5 for PCSC, with no significant differences among the groups, p = 0.173. Cycles to failure and failure load were 7822 ± 2281 and 982.2 ± 428.1 N for PCPF, 3662 ± 1664 and 566.2 ± 366.4 N for PCSF, and 5989 ± 3440 and 798.9 ± 544.0 N for PCSC, being significantly higher for PCPF versus PCSF, p = 0.012.ConclusionStandard ORIF of PCF with either plate osteosynthesis or using a screwable cup for THA demonstrated encouraging results for application of a post-surgical treatment concept with a full weight bearing approach. Further biomechanical cadaveric studies with larger sample size should be initiated for a better understanding of AF treatment with full weight bearing and its potential as a concept for PCF fixation.

Revision total hip arthroplasty by a ceramic bearing surface after a third- and fourth-generation ceramic head or liner fracture.

Although rare, fractures of ceramic components are difficult to revise, mainly due to the presence of residual ceramic debris that can cause catastrophic wear of the replacement components. Modern ceramic-on-ceramic bearings are suggested to improve outcomes of revision total hip arthroplasty (THA) for ceramic fractures. However, there are few published reports of mid-term outcomes of revision THA using ceramic-on-ceramic bearings. We evaluated clinical and radiographic outcomes of 10 patients who received ceramic-on-ceramic bearings during revision THA for ceramic fractures. All patients but one received fourth-generation Biolox Delta bearings. Clinical evaluation was performed using the Harris hip score at latest follow-up, and all patients received a radiographic evaluation to analyze the fixation of the acetabular cup and of the femoral stem. Osteolytic lesions and the presence of ceramic debris were noted. After a mean follow-up of 8.0 years, there were no complications or implant failures, and all patients reported satisfaction with their implant. The average Harris hip score was 90.6. There was neither osteolysis nor loosening, but despite our extensive synovial debridement, ceramic debris was noted in the radiographs of five patients (50%). We report excellent mid-term outcomes, with no implant failures after eight years despite ceramic debris being found in a significant proportion of patients. We conclude that modern ceramic-on-ceramic bearings are an advantageous option for the revision of THA due to the fracture of initial ceramic components.

Ischial screw fixation can prevent cup migration in 3D-printed custom acetabular components for complex hip reconstruction

IntroductionCustom acetabular components have become an established method of treating massive acetabular bone defects in hip arthroplasty. Complication rates, however, remain high and migration of the cup is still reported. Ischial screw fixation (IF) has been demonstrated to improve mechanical stability for non-custom, revision arthroplasty cup fixation. We hypothesize that ischial fixation through the flange of a custom acetabular component aids in anti-rotational stability and prevention of cup migration.MethodsElectronic patient records were used to identify a consecutive series of 49 custom implants in 46 patients from 2016 to 2022 in a unit specializing in complex joint reconstruction. IF was defined as a minimum of one screw inserted into the ischium passing through a hole in a flange on the custom cup.The mean follow-up time was 30 months. IF was used in 36 cups. There was no IF in 13 cups. No difference was found between groups in age (68.9 vs. 66.3, P = 0.48), BMI (32.3 vs. 28.2, P = 0.11) or number of consecutively implanted cups (3.2 vs. 3.6, P = 0.43). Aseptic loosening with massive bone loss was the primary indication for revision. There existed no difference in Paprosky grade between the groups (P = 0.1). 14.2% of hips underwent revision and 22.4% had at least one dislocation event.ResultsNo ischial fixation was associated with a higher risk of cup migration (6/13 vs. 2/36, X2 = 11.5, P = 0.0007). Cup migration was associated with an increased risk for all cause revision (4/8 vs. 3/38, X2 = 9.96, P = 0.0016, but not with dislocation (3/8 vs. 8/41, X2 = 1.2, P = 0.26).ConclusionThe results suggest that failure to achieve adequate ischial fixation, with screws passing through the flange of the custom component into the ischium, increases the risk of cup migration, which, in turn, is a risk factor for revision.

Midterm Outcomes of a Monoblock Dual-Mobility Cup Cemented into a Fully Porous Acetabular Component in Revision Total Hip Arthroplasty

AbstractUtilization of dual-mobility (DM) constructs has been a promising management option to address the risk of hip instability after complex revision total hip arthroplasty (rTHA). The aim of this study is to report a minimum 2-year outcome and survivorship of a monoblock DM cup cemented in a fully porous acetabular shell in complex acetabular rTHA cases. A retrospective review of 76 patients who underwent rTHA with a novel construct that utilized an inner DM cup cemented into a fully porous outer acetabular metal shell was conducted. Demographics, radiographic, and clinical outcomes such as readmissions, dislocation, and revisions were collected. Survivorship was analyzed by the Kaplan–Meier (KM) method. Thirty cases with a minimum of 2-year follow-up were included. Patients were, on average, 65.17 ± 10.26 years old with a mean body mass index of 28.55 ± 6.33 kg/m2. Seven patients (23.3%) required reoperations. Four patients underwent acetabular revision (periprosthetic joint infection: n = 2 [6.7%]; dislocation: n = 1 [3.3%]; aseptic loosening [fully porous cup]: n = 1[3.3%]). Three patients underwent reoperation without acetabular implant revision (debridement, antibiotics, and implant retention for prosthetic joint infection: n = 2 [6.7%]; femoral periprosthetic fracture: n = 1 [3.3%]). KM survivorship analysis of all-cause acetabular revision showed survival rates of 96.7% at 6 months, 93.3% at 1 year, and 89.7% at 2 years. KM survivorship of aseptic acetabular revision showed rates of 96.7% at 1 year and 92.9% at 2 years. KM analysis of acetabular cup fixation showed rates of 100% at 1 year and 96.2% at 2 years. The rate of dislocation in our cohort was 3.3% (1 out of 30). The use of a DM acetabular cup cemented into a fully porous acetabular revision shell in complex rTHA cases has a low risk of instability and loosening at 2 years with excellent mid-term implant survivorship. The use of this construct is a good option in patients with complex acetabular reconstruction and an elevated risk for instability. This was a retrospective cohort study with a level III evidence.

Efficacy and Safety of Acetabular Cup without Screw Fixation in Total Hip Arthroplasty: A Systematic Review and Meta-Analysis.

Background and Objectives: Adequate initial fixation of the uncemented acetabular component in total hip arthroplasty is necessary to achieve long-term survival. Although screw fixation contributes to improved cup stability, there is currently no consensus on the use of this method. This study aimed to assess the existing randomized controlled trials (RCTs) on the efficacy and safety of cup fixation in total hip arthroplasty without screws. Materials and Methods: We searched the EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov databases to identify RCTs published before February 2022. Primary outcomes were reoperation, cup migration, and Harris Hip Score. Secondary outcomes were the presence of a radiolucent line in the acetabular region, translation and rotation movement, and polyethylene wear. We conducted meta-analyses using the random-effects models. The revised Cochrane risk-of-bias tool was used to assess the risk of bias for outcomes of interest; the Grading of Recommendations, Assessment, Development, and Evaluation approach was used to summarize the body of evidence. Results: We included six reports from four studies. Total hip arthroplasty without screw fixation to the acetabular cup had little to no effect on reoperation (pooled relative risk, 0.98; 95% confidence interval, 0.14–6.68; I2 = 0%), cup migration (pooled relative risk, 1.72; 95% confidence interval, 0.29–10.33; I2 = 1%), Harris Hip Score (mean difference, 1.19; 95% confidence interval, −1.31–3.70; I2 = 0%), radiolucent line (pooled relative risk, 5.91; 95% confidence interval, 0.32–109.35), translation and rotation of all axes, and polyethylene wear (mean difference, 0.01; 95% confidence interval, −0.01–0.04; I2 = 0%), with very low certainty of evidence on all measures. Conclusions: The efficacy of acetabular cups without screw fixation in total hip arthroplasty remains uncertain, suggesting the need for prudent clinical application. Further large-scale, well-designed studies with low risk of bias are required.