Cup Migration Research Articles

Dual-mobility cups in revision acetabular reconstructions: Short-term outcomes in high-risk patients for instability

ObjectiveThe aim of this study was to evaluate the performance of dual-mobility (DM) cup systems for revision total hip arthroplasty (rTHA) in patients who had high risk for instability. MethodsWe prospectively followed up 34 hips of 30 patients (27 females, 3 males; mean age: 66.1 (range: 33 to 89) years) who underwent rTHA with DM cups for aseptic loosening in 23 hips, infection treatment as second or single stage in nine hips, and instability in two hips. Clinical functions of the patients were evaluated using the Harris Hip Score (HHS), and radiological migration or loosening of the DM cups were recorded. The survival of the components was calculated with the Kaplan-Meier survival analysis and failure was defined as any dislocation of the polyethylene (PE) insert, intraprosthetic dislocation (IPD), aseptic loosening of any component or total hip system revision due to any reason. ResultsThe mean duration of follow-up was 3.52 (range: 2.05 to 6.26) years. There was one dislocation of PE insert (2.9%), which was treated with closed reduction. There were two (5.8%) re-revisions for cemented DM cup due to migration. There was one PE insert and head change due to subacute infection. The mean HHS increased from 42.8 ± 6.7 (range: 34 to 60) points preoperatively to 87.3 ± 5.8 (range: 75 to 98) points postoperatively. The cumulative survival rate of the DM cup system was 91.2% (95% CI: 81.6–100%) with any revision, 94.1% (95% CI: 86.2–100%) with aseptic loosening and %97.1 (%95 CI: 91.4–100%) with dislocation as the end point at 3.5 years. ConclusionDual-mobility cups may provide good stability and represent a good option for revision acetabular reconstruction in patients who have high risk for instability. Level of evidenceLevel IV, therapeutic study.

Conversion of Failed Hip Hemiarthroplasty to Low Friction Arthroplasty (LFA).

Purpose: We aimed to study clinical and radiological outcomes of conversion from hemiarthroplasty to Charnley hip replacement (CHR) with a particular concern over reported increased dislocation rate and literature review. Conversion of hip hemiarthroplasty to total hip replacement (THR) is a procedure reported to have high rates of complications. In the literature, there is no specific study on small head conversion. The purpose of this study was to evaluate the conversion of failed hip hemiarthroplasty to CHR with the use of modern implants. Methods: The study included 42 patients, who underwent the above procedure. The operations were carried out using a modern Charnley-type THR with a 22-mm diameter of femoral head and a trans-trochanteric approach. The mean follow-up was 75.7 months (range 25–171). Radiographs from the last follow up were evaluated for loosening and other reasons of failure. Clinical outcome was assessed using postoperative pain, function scores, complications and implant survivorship as well as radiological evaluation. Charnley’s modified pain and mobility scoring system were used for clinical and Hodgkinson and Harris’ criteria were used for radiological assessment. Results: Functionally, all of the patients showed improvement. Mean improvement in the pain level was by average of 2.4. On mobility assessment, 38 patients (90.4%) improved. Three patients (7.1%) had recurrent infections and three (4.8%) cases were treated with revision surgery and pseudarthrosis. Further complications occurred in 19.1%, not requiring operative treatment. On radiological evaluation, one (2.4%) case showed cup demarcation without bone loss, two (4.8%) cup migration, and one (2.4%) stem demarcation. Kaplan Meier survival analysis showed a survival of 90% at 96 months of follow up (95% CI (confidence interval), 60–90). Conclusion: Larger head might not be the answer to decrease the dislocation rate. Complication rates during revision of hip hemiarthroplasty to modern CHR with 22.225-mm head diameter were comparable to first-time THR revision despite having a smaller head.

Intra-Pelvic Cup Migration as an immediate Post-Operative Complication

Intra-Pelvic Cup Migration as an immediate Post-Operative Complication

The use of pararectus approach for Type 3B Paprosky acetabular defect with intrapelvic cup migration. Case report.

Case: A case of Type 3B Paprosky acetabular defect with intrapelvic cup migration where anterior column plating and cup extraction was done through an abdominal pararectus approach.A male patient 63 years old reported progressive pain and walking disability after five years of cementless THR for right hip AVN.CT pelvis showed loose intrapelvic migrated cup, extensive osteolytic acetabular defects, and pelvic discontinuity.Pararectus approach was used to remove the cup and the head with concomitant plating of the anterior column Conclusion: The pararectus approach is a valid option for intrapelvic cup extraction and pelvic discontinuity fixation.

Revision Total Hip Arthroplasty for Paprosky Type III Acetabular Defect With Structural Allograft and Tantalum Trabecular Metal Acetabular Cup.

There are several surgical options for addressing Paprosky type III acetabular defects during revision total hip arthroplasty. In physiologically young and active patients, using structural bone graft to restore bone defects and provide adequate initial support for the revision acetabular component is one such option. This study reports the mid-term results of using a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. A retrospective analysis was performed of the data collected for 20 consecutive hips in 20 patients (mean age, 56.2 years; range, 43-68 years) with minimum 3-year follow-up (mean, 5.4 years; range, 3.3-10.3 years) who had a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. Only 1 hip had cup migration, which was less than 3 mm in vertical and less than 5° in inclination and recognized as loosening without symptoms. All grafts showed good incorporation with trabecular bridging over the graft and host bone. The mean modified Harris hip score showed significant improvement, from 29.7 (range, 11-52) preoperatively to 84.1 (range, 77-91) at the latest follow-up (P<.05). The use of a structural allograft combined with a tantalum trabecular metal acetabular cup in acetabular revision for Paprosky type III defects had a satisfactory mid-term clinical result. This is a viable option for patients with large acetabular shelf defects. [Orthopedics. 2018; 41(6):e861-e867.].

Model-based roentgen stereophotogrammetric analysis using elementary geometrical shape models: 10\xa0years results of an uncemented acetabular cup component

BackgroundNon-cemented acetabular cup components demonstrated different clinical performance depending on their surface texture or bearing couple. However, clinical osseointegration needs to be proved for each total joint arthroplasty (TJA) design. Aim of this study was to detect the in vivo migration pattern of a non-cemented cup design, using model-based roentgen stereophotogrammetric analysis with elementary geometrical shape models (EGS-RSA) to calculate early cup migration.MethodsInterchangeable applicability of the model-based EGS-RSA method next to gold standard marker-based RSA method was assessed by clinical radiographs. Afterwards, in vivo acetabular cup migration for 39 patients in a maximum follow up of 120 months (10 years) was calculated using model-based EGS-RSA.ResultsFor the axes with the best predictive capability for acetabular cup loosening, mean (±SD) values were calculated for migration and rotation of the cup. The cup migrated 0.16 (±0.22) mm along the cranio-caudal axis after 24 months and 0.36 (±0.72) mm after 120 months, respectively. It rotated − 0.61 (±0.57) deg. about the medio-lateral axis after 24 months and − 0.53 (±0.67) deg. after 120 months, respectively.ConclusionsInterchangeable applicability of model-based EGS-RSA next to gold standard marker-based RSA method could be shown. Model-based EGS-RSA enables an in vivo migration measurement without the necessity of TJA specific surface models. Migration of the investigated acetabular cup component indicates significant migration values along all the three axes. However, migration values after the second postoperative year were within the thresholds reported in literature, indicating no risk for later aseptic component loosening of this TJA design.

L’appui complet immédiat est-il possible en cas de fracture de l’arrière-fond acétabulaire au cours d’une arthroplastie totale de hanche ?

BackgroundA breach of the medial acetabular wall is a phenomenon seen frequently due to over-reaming during total hip arthroplasty (THA). The consequences of this issue are not fully understood particularly in cementless THA. A retrospective study was performed to answer whether: (1) immediate postoperative full-weight bearing in the presence of a medial acetabular wall breach after THA results in more short-term revisions of the acetabular component, (2) increases the risk for migration of the acetabular component? HypothesisImmediate full-weight bearing in the presence of a medial breach is not associated with an increased likelihood for acetabular-related revision surgery or migration of the cup. Patients and methodsIn this retrospective cohort study, consecutive patients (n=95; mean age 68±13 years; 67 female) who underwent THA with an uncemented acetabular component were identified and a retrospective chart review was performed (follow-up 23±17 months, range 6 to 79 months). The presence of a postoperative radiographic medial acetabular breach was documented and the need for revision surgery and the rate of acetabular component migration were assessed during follow-up. ResultsSome extent of radiographic medial acetabular wall breach was seen in 26/95 patients (27%). With regard to the primary outcome, 2/95 patients (2%) required revision surgery during follow up. All revision surgeries occurred in the group without a medial breach (p=0.280) for causes related to the femoral or the head components. Persistent pain was present in 1/26 patients (3.8%) in the medial breach group and 8/69 patients in the control group (11.6%; p=0.436). In the radiographic follow-up, (n=81), there was no significant difference between the control group and the medial breach group with regard to cup migration (Δ ilio-ischial overlap (distance between the ilio-ischial line and a parallel line tangential to the acetabular cup on AP views): −0.5±0.9mm (range, −2.9 to 0.8) vs. −0.3±1.7mm (range, −1.9 to 2.2), Δ overlap tangent (defined as the distance between the two crossings of ilio-ischial line and the acetabular component on AP views): −2.2±6.1mm (range, −21.4 to 0.0) vs. 0.4±6.9mm (range, −6.2 to 17.6). Similarly, according to variation in the ilio-ischial overlap distance between postoperative and follow-up on pelvic AP views, 0/56 hips (0%) had cup migration≥5mm in the control group versus 1/25 (4%) in the medial breach cohort (p=0.3). DiscussionIn this retrospective observation of patients with immediate postoperative full-weight bearing after THA, a radiographic breach of the medial acetabular wall was not associated with an increased risk for short-term revision surgery or radiographic migration at follow-up. According to the findings of this study and in the light of previous biomechanical studies, there is no clear evidence for postoperative partial-weight bearing in case of a medial breach as far as the surgeon feels that the acetabular component is stable. Level of evidenceIV, Retrospective cohort study.

Occult intra-operative periprosthetic fractures of the acetabulum may affect implant survival.

Occult intra-operative periprosthetic acetabular fracture is a seldom-reported complication of primary total hip arthroplasty (THA). It may potentially be associated with cup instability and implant loosening. The present study aimed to investigate clinical consequences of this complication. Between 2003 and 2012, a total of 3390 cementless total hip arthroplasties (THA) were performed at our institution. Their medical histories were retrospectively reviewed to identify all patients who received a thin-layer computer tomography (CT) scan of the pelvis including the acetabulum within the first 30 post-operative days. They were evaluated and classified by two radiologists independently with respect to the presence of recent acetabular fractures. All cases with acetabular and periacetabular fractures were included in this study. Electronic medical records were reviewed to assess implant revision. Cup stability was measured with EBRA (Einzel-Bild-Röntgen-Analyse) from plain X-rays. Periprosthetic fractures of the acetabulum were identified in 58 (50.4%) of 115 selected patients. Fractures close to but not including the acetabulum were identified in 45% (n = 26/58) of the patients, at the superolateral wall in 17% (n = 10/58), at the anterior wall of the acetabulum in 16% (n = 9/58) and in 10% (n = 6/58) each at the medial wall, and at the posterior wall respectively. One out of these 58 fractures could not be classified. Three of a total of six occult medial wall fractures had to be revised, and another two showed a high implant migration. The highest cup migration values however were found after fractures of the superolateral wall. Incomplete column fractures did not influence implant survival. Central wall acetabular fractures, although unrecognized intra- and post-operatively may impair implant survival after THA.

Medial acetabular wall breach in total hip arthroplasty - is full-weight-bearing possible?

A breach of the medial acetabular wall is a phenomenon seen frequently due to over-reaming during total hip arthroplasty (THA). The consequences of this issue are not fully understood particularly in cementless THA. A retrospective study was performed to answer whether: immediate postoperative full-weight-bearing in the presence of a medial acetabular wall breach after THA results in more short-term revisions of the acetabular component, and increases the risk for migration of the acetabular component? Immediate full-weight-bearing in the presence of a medial breach is not associated with an increased likelihood for acetabular-related revision surgery or migration of the cup. In this retrospective cohort study, consecutive patients (n=95; mean age 68±13 years; 67 female) who underwent THA with an uncemented acetabular component were identified and a retrospective chart review was performed (follow-up 23±17 months, range 6 to 79 months). The presence of a postoperative radiographic medial acetabular breach was documented and the need for revision surgery and the rate of acetabular component migration were assessed during follow-up. Some extent of radiographic medial acetabular wall breach was seen in 26/95 patients (27%). With regard to the primary outcome, 2/95 patients (2%) required revision surgery during follow-up. All revision surgeries occurred in the group without a medial breach (p=0.280) for causes related to the femoral or the head components. Persistent pain was present in 1/26 patients (3.8%) in the medial breach group and 8/69 patients in the control group (11.6%; p=0.436). In the radiographic follow-up (n=81), there was no significant difference between the control group and the medial breach group with regard to cup migration (Δ ilio-ischial overlap [distance between the ilio-ischial line and a parallel line tangential to the acetabular cup on AP views]: -0.5±0.9mm [range, -2.9 to 0.8] vs. -0.3±1.7mm [range, -1.9 to 2.2], Δ overlap tangent [defined as the distance between the two crossings of ilio-ischial line and the acetabular component on AP views]: -2.2±6.1mm [range, -21.4 to 0.0] vs. 0.4±6.9mm [range, -6.2 to 17.6]). Similarly, according to variation in the ilio-ischial overlap distance between postoperative and follow-up on pelvic AP views, 0/56 hips (0%) had cup migration ≥ 5mm in the control group versus 1/25 (4%) in the medial breach cohort (p=0.3). In this retrospective observation of patients with immediate postoperative full-weight-bearing after THA, a radiographic breach of the medial acetabular wall was not associated with an increased risk for short-term revision surgery or radiographic migration at follow-up. According to the findings of this study and in the light of previous biomechanical studies, there is no clear evidence for postoperative partial weight-bearing in case of a medial breach as far as the surgeon feels that the acetabular component is stable. IV, Retrospective cohort study.

Dual-mobility bearings for patients with abductor-trochanteric complex insufficiency.

The purpose of this study was to summarise the performance of dual-mobility cup systems for revision total hip arthroplasty in patients with abductor-trochanteric complex deficiency. We prospectively followed 17 patients (20 hips) with a mean age of 64.5 years (range 33-89 years) who underwent acetabular reconstruction with dual-mobility cups for aseptic loosening in 12 hips, infection treatment as second or single stage in 6 hips, and instability in 2 hips. All of the patients had abductor insufficiency. We evaluated the clinical Harris Hip scores (HHS) and radiographs for migration, loosening, and osteolysis. The survival of the components was calculated according to Kaplan-Meier survivorship analysis, and failure was defined as any dislocation, acetabular component or total hip revision for any reason. The mean duration of follow-up was 38.1 months (range 24-98 months). There were 2 (12.5%) revisions for cemented cup migration after 11 months and 19 months respectively. There were no dislocations. At the last follow-up, the mean HHS increased from 42 points preoperatively to 86 points. The cumulative survival rate of the dual-mobility cup system was 93% (95% confidence interval 88-98.7%) at 5 years, with any revision as the end point. Dual-mobility cups may provide excellent stability in patients with abductor-trochanteric complex insufficiency.

Midterm outcome of fourth-generation ceramic-on-ceramic bearing surfaces in revision total hip arthroplasty.

The purpose of this study is to evaluate the clinical and radiologic outcomes after revision total hip arthroplasty (THA) using fourth-generation ceramic-on-ceramic (CoC) bearing surfaces. A total of 52 revision THAs (28 men and 19 women) using the fourth-generation CoC bearing surfaces were retrospectively evaluated. Both acetabular cup and femoral stem were revised in all cases. The mean follow-up period was 7.3 years (range, 4.0-9.9 years). The clinical results with Harris hip score (HHS), Western Ontario McMaster Osteoarthritis Index (WOMAC), and radiologic outcomes were evaluated. At the final follow-up examination, the average HHS was 90.4 (range, 67-100). The average WOMAC pain and physical function score were 2.8 (range, 0-12) and 16.4 (range, 0-42), respectively. Complications were observed in 10 hips (19.2%). However, there were no bearing surface-related complications, and no cases of dislocation and squeaking. Retroacetabular pelvic osteolysis without cup loosening was observed in one hip at the final follow-up. However, no hip showed radiographic signs of cup loosening, vertical or horizontal acetabular cup migrations, and changes of inclinations during the follow-up period. Our data showed that clinical and radiologic outcomes after revision THA using fourth-generation CoC bearing were favorable. Hence, revision THA with the use of CoC bearing surfaces can be preferentially considered. Further studies with long-term follow-up data are warranted.

Impacted morsellised allograft and cemented cup in acetabular revision surgery. A five to nine year follow-up study.

Seventy cemented cups associated with impacted morsellised allograft in revision surgery in hips with an acetabular bone defect greater than 30% (Paprosky Grades 3A and 3B) were analyzed. The mean follow-up was 6.8 years. One hip showed cup migration and was re-revised; this represents a total cumulative probability of re-revision of the cup of 1.4 2.8%. Radiolucent lines were uncommon: six cups showed radiolucent lines in DeLee and Charnley zone 1, five in zones 1 and 2, one in all three zones, while one hip showed migration.Although the frequent use of a metallic mesh makes graft remodeling difficult to evaluate, six hips showed minor and one major bone resorption. The mid-term results with impacted allograft and cemented all-polyethylene cups are favourable in acetabular revision surgery. (Hip International 2002; 12: 281-8).

Clinical results of hemiarthroplasty using new bipolar cups for stage 3 or lower osteonecrosis of the femoral head: a retrospective study

The aim of this study was to evaluate clinical and radiographic findings of stage 3 or lower osteonecrosis of the femoral head (ONFH) with intact acetabular cartilage in patients treated with bipolar hemiarthroplasty (BHA). A total of 79 hips that underwent BHA for ONFH were included in this study. The average observation period was 7.6years. Clinical results were evaluated using the Harris hip score. We performed radiographic analysis to assess the migration of the outer cup, the permanent image around the outer cup, and loosening of the stem. The total Harris hip score improved from 50 points before surgery to 92 points at final follow-up, while pain improved from 14 points to 36 points. Flexion improved from 94° to 120° and abduction from 27° to 37°. One patient on dialysis showed progress in terms of inward migration, and revision surgery was performed on the patient 14years after the original surgery. Midterm performance of BHA for stage 3 or lower ONFH at our hospital was good.

Bone morphogenic protein-2 use in revision total hip arthroplasty with acetabular defects.

The restoration of acetabular bone stock during revision hip arthroplasty remains a challenge. There have been no clinical series reporting the efficacy of bone morphogenic protein-2 (rhBMP-2) in the revision hip setting. We retrospectively reviewed the radiographs and records of 15 patients who received rhBMP-2 mixed with allograft bone chips (+BMP), and 14 who received allograft bone chips alone (-BMP) for their acetabular defect during revision total hip arthroplasty with a mean two-year follow up. Radiographs were evaluated for acetabular defect size, superior cup migration, and changes in the lateral cup abduction angle. Modified Harris hip scores were used for evaluation of clinical outcomes. Patients in the +BMP group compared to the -BMP group had significantly larger amounts of cancellous bone chips used (72.1±35.5cc vs. 38.6±14.1cc; p=0.003). Mean rhBMP-2 used per case was 7.4±3.1mg in the +BMP group. Three patients in the -BMP group had cup migration which was not observed in the +BMP group. Mean Harris hip scores (HHS) improved post-operatively in both groups (40.1±20.9 to 71.9±19, p<.0001). No local adverse reaction was noted in the +BMP group. rhBMP-2 had modest clinical benefit in the setting of revision THA. Cost of this synthetic biologic versus the added clinical benefit should be carefully considered when being used in the revision hip setting.

Mid-term migration of a cementless, porous acetabular cup: A 5 year Radiostereometric analysis

PurposeThe aim of the study was to determine the 5 year migratory and wear patterns, adverse events and clinical outcomes of a cementless, porous acetabular cup. MethodsRSA imaging of a cohort of 11 patients was retrospective analysed at 5 years post Total Hip Arthroplasty (THA). Changes in pain, function and symptoms of the hip at 5 years post-THA were compared to preoperative and 2 year postoperative assessments on the Harris Hip Score (HHS) and Hip dysfunction and Osteoarthritis Outcome Score (HOOS). ResultsThe majority of cup migration occurred up to 6 months and stabilised thereafter (6 months to 5 years, p=0.091–0.866, Wilcoxon Signed Rank test). The direction of rotation around the 3 axes was evenly distributed among the cups between anterior-posterior rotation, internal-external rotation and increased-decreased inclination. The majority of the cups translated proximally, at an average migration of 0.36mm (±95%CI 0.17) at 5-years post-THA. Following initial bedding in, up to 6 months, there was no detectable polyethylene wear between 6 months and 5 years. At 5 years postoperatively, a statistically significant difference was observed across all HOOS subscales in comparison to preoperative values, with higher means reported at 5 years (p<0.001). The total mean HHS displayed a statistically significant improvement, increasing from ‘poor’ preoperatively to ‘good’ at 5 years post-THA. ConclusionFollowing initial migration between discharge and 6 months, the cementless porous acetabular cup demonstrated a tendency for stabilisation from 6 months up to 5 years post-THA, suggesting good mid-term fixation. Additionally, improvements in clinical outcome measures of pain, function and quality-of-life remained high following THA at 5 years post-surgery.

Impaction bone grafting with reinforcement metallic mesh and cemented cup for the treatment of Paprosky 3B acetabular defects

Depending on the bone defect, cup revision can be a highly complex operation. Cup loosening, produces cup migration and acetabular bone defects and the size of these bone defects will determine the technique used for acetabular cup revision. Migration of the cup also requires that to obtain a good clinical result, the center of rotation of the hip be reconstructed so the cup is played in the anatomic rotation center of the hip. The acetabular bone stock must be ideal to support the cup. There must be enough medial bone stock and supportive rims to obtain a long-term result.

Acute intrapelvic cup migration: advantages of adyuvant Stoppa approach for implant removal/reconstruction. A case report

Acute intrapelvic cup migration: advantages of adyuvant Stoppa approach for implant removal/reconstruction. A case report

Clinical evaluation of model‐based radiostereometric analysis to measure femoral head penetration and cup migration in four different cup designs

In conventional Radiostereometric analysis (RSA) implants with attached tantalum markers are frequently used, which may be difficult to visualize. This problem can be avoided with model-based RSA (MBRSA), but it is uncertain if this method has the same precision as marker-based RSA. We evaluated the influence of cup design for the precision of MBRSA in four uncemented cups to study if the design had any influence on the precision. Stereo radiographs were analyzed postoperatively (double-examinations) and after 2 years (single examinations). The difference between the double-examinations was used to compute the precision for the methods and for each type of implant. Femoral head penetration and cup translation up to 2 years were compared using marker-based RSA as reference. The precision of proximal penetration and migration measurements did not differ between the methods for Trilogy, TMT and ABG. For Ringloc design a poorer precision was observed using MBRSA. Comparison between the methods regarding proximal penetration and cup migration at 2 years did not differ for three of the designs (p = 0.12-0.91). However, for the group with porous plasma sprayed surface (Ringloc) a significant difference between the methods was observed (ppenetration <0.01 and pmigration <0.01). Poorer precision, different penetration and migration values at 2 years for one of the designs indicate that the resolution of MBRSA might vary depending on surface coating and implant geometry. Therefore, we conclude that the resolution of MBRSA has to be studied for each type of basic cup design. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:760-767, 2017.

Bone mineral density decreased is a high risk factor for uncemented acetabular cups migration in female total hip arthroplasty patients

To investigate the decrease of bone mineral density in female patients, effects on acetabular displacement. From October 2013 to November 2015, a total of 34 patients underwent total hip replacement in the Department of orthopedics, the Third Affiliated Hospital of Zunyi Medical College. The two groups of patients were female and the patients were treated with hip osteoarthritis. Based on the lowest value of preoperative dual energy X-ray bone mineral density (DXA), the patients were divided into normal group and low bone mineral density(-3.5<=T<=-1). There were 10 patients in the normal group, ranging in age from 55 to 64 years old, with an average of (58.00±4.22) years old. There were 24 patients in the low bone density group, ranging in age from 58 to 72 years old, with an average age of (65.71±8.19) years old. All the patients received a THA implant with ceramic-on-ceramic bearings(Depuy America). The lining system was Pinnacle cup. During the operation, the acetabular cup was maintained at abduction 45 degree and anteversion 15 degree. Analysis (RSA) of acetabular components in 3, 6, 12, and 24 months after surgery. There was a statistically significant difference in cup migration between patients with normal BMD and those with low BMD. At 3 months, compare to the normal group, the low bone mineral density (BMD) occurred in the X axis (95% confidence interval, 0.01 to 0.31; P=0.006) and Y (95% confidence interval 0.20 to 0.39; P=0.003). The initial rotation occurs in a separate Z axis(95% confidence interval -0.26 to 0.81; P=0.006). It has produced that increaseed migration of uncemented cups in female patients with low systemic BMD in 3 months after surgery.

Acetabular components with or without screws in total hip arthroplasty

AIMTo compare the operation time, blood loss, and early outcomes of acetabular components with and without the screw.METHODSThirty patients who underwent cementless acetabular component with or without screw and whose follow-up exceeded one year period in total hip arthroplasty were evaluated. A posterior approach was used in all surgical procedures by one experienced surgeon. Demographic data, operation time, intra- and postoperative blood loss volume, follow-up clinical score, cup migration, and osteolysis were recorded. The Kolmogorov-Smirnov test was performed for testing the normality of study data. Mann-Whitney U test was used to analyze the inter-group differences. A P-value of ≤ 0.05 was considered statistically significant.RESULTSAcetabular components were used in 16 (53.3%) patients with screw and 14 (46.7%) without screw. After one year of follow-up, an osteolytic lesion of 3 mm was found in only one patient in the screw group. No cup migration was encountered. Intra-group mean Harris hip score significantly increased, but there was no significant inter-group difference. While the mean operation time of the screw group was 121.8 min (range; 95-140), it was 102.7 min (range; 80-120) in the no-screw group, and this difference was statistically significant (P = 0.002). The mean intraoperative/postoperative, and total blood loss were 556.6 mL (range: 350-800)/423.3 mL (range: 250-600), and 983.3 mL (range: 600-1350), respectively in the screw group; and 527 mL (range: 400-700)/456 mL (range: 230-600), and 983 mL (range: 630-1250), respectively in the no-screw group. The blood loss difference between the two groups was not significant. In the screw group, the operation time was 19.1 min longer than the no-screw group, and this difference was statistically significant.CONCLUSIONAcetabular components with or without screw have similar results, but the use of screw increases the operation time significantly, while not changing the blood loss volume.