Accurate Acetabular Component Orientation After Total Hip Arthroplasty Using an Acetabular Alignment Guide

Between February 2005 and August 2006, we recorded acetabular component orientation in 90 patients (100 hips) who underwent primary total hip arthroplasty (THA), to determine whether using an alignment guide ensures accurate acetabular positioning. In the alignment-guide group (46 patients; 48 hips), a guide was placed on the pelvis, a Kirschner wire (K-wire) was attached to the guide, and orientation of the acetabular component was confirmed by both the surgeon and an assistant. In the control group (44 patients; 52 hips), a K-wire was not used and the angle was confirmed by the surgeon alone. Radiographic acetabular component inclination and anteversion and computed tomography anteversion were determined. There was no significant difference in mean component orientation between the 2 groups. However, the SD was significantly smaller in the alignment-guide group, showing that consistent acetabular component orientation in primary THA is highly reproducible when an acetabular alignment guide with an attached K-wire is used.     

Effect of Acetabular Component Positioning on Functional Outcomes in Primary Total Hip Arthroplasty

Background

Acetabular component positioning is crucial to a successful total hip arthroplasty (THA). This study evaluated the effect of absolute acetabular component position as well as acetabular position relative to bony anatomy on patient-reported functional outcomes after primary THA.

Limitations of Imageless Computer-Assisted Navigation for Total Hip Arthroplasty

We prospectively evaluated acetabular cup placement in total hip arthroplasty with an imageless computer navigation system or using conventional manual technique. The achieved cup orientation in the manual group had substantially larger variances and greater placement error than the navigation cases. The use of navigation was abandoned in 3 cases because of excessive pelvic tilt and unreliable registration of the pelvis. Computer navigation system helped improve the accuracy of the acetabular cup placement for total hip arthroplasty in this study. The variation between the intraoperative navigation readings and the computed tomographic values suggests that relying on palpation of bony landmarks through drapes and tissue is a limitation of this method. Further, the variation in pelvic tilt has an effect on cup placement that requires further studies.     

Periacetabular Bone Mineral Density Changes After Resurfacing Hip Arthroplasty Versus Conventional Total Hip Arthroplasty. A Randomized Controlled DEXA Study

A randomized controlled trial was performed to evaluate acetabular bone mineral density (BMD) changes after hip resurfacing (RHA) versus an established conventional total hip arthroplasty (THA). A total of 71 patients were allocated randomly to receive either an RHA press-fit cobalt–chromium cup (n = 38) or a THA with a threaded titanium cup and polyethylene-metal-inlay insert (n = 33). The BMD in five separate periacetabular regions of interest (ROI) was prospectively quantified preoperative until 24 months. We conclude that, in contrast to our hypothesis, periacetabular BMD was better preserved after RHA than after placement of a conventional THA. Long term follow-up studies are necessary to see whether this benefit in bone preservation sustains over longer time periods and whether it is turned into clinical benefits at future revision surgery.     

Research Synthesis of Recommended Acetabular Cup Orientations for Total Hip Arthroplasty

Total hip arthroplasty (THA) is regarded as one of the most successful surgical procedures of modern times yet continues to be associated with a small but significant complication rate. Many early failures may be associated with poor component positioning with, in particular, acetabular component orientation dependent on the subjective judgement of the surgeon. In this paper, we compare the manufacturers' instructions on acetabular cup orientation with the literature-based recommended safety zones and surgical technique, by transforming them onto a single, clinically-relevant framework in which the different reference systems, safety guidelines and current instrumentation surgical techniques can be evaluated. The observed limited consensus between results reflects ongoing uncertainty regarding the optimum acetabular component positioning. As malpositioning of the acetabular cup increases the risk of revision surgery, any ambiguity over the correct position can have a causal effect. Our analysis highlights the need for a surgical reference system which can be used to describe the position of the acetabular cup intra-operatively.     

Primary Total Hip Arthroplasty With a Spongy Metal Surface Acetabular Component for Hip Dysplasia

We evaluated the clinical and radiographic results of primary total hip arthroplasty for 81 dysplastic hips (71 patients) using cementless Spongiosa Metal II cups (ESKA Implants, Lübeck, Germany). The mean follow-up period was 6.4 years (minimum 5 years), and the preoperative mean Japanese Orthopaedic Association hip score had improved from 45.2 to 87.4 points at the latest follow-up. The radiographic outcome was no aseptic loosening in all 81 hips. The hip center was located significantly more superior than in the contralateral normal hip in 45 patients, but the difference was less than 10 mm; however, there was no significant difference in the lateral position of the hip center. The use of a Spongiosa Metal II cup for dysplastic hips provided satisfactory 5- to 10-year clinical and radiographic results.     

Augmented Reality for Acetabular Component Placement in Direct Anterior Total Hip Arthroplasty

BackgroundMalposition of the acetabular component of a hip prosthesis can lead to poor outcomes. Traditional placement with fluoroscopic guidance results in a 35% malpositioning rate. We compared the (1) accuracy and precision of component placement, (2) procedure time, (3) radiation dose, and (4) usability of a novel 3-dimensional augmented reality (AR) guidance system vs standard fluoroscopic guidance for acetabular component placement.MethodsWe simulated component placement using a radiopaque foam pelvis. Cone-beam computed tomographic data and optical data from a red-green-blue-depth camera were coregistered to create the AR environment. Eight orthopedic surgery trainees completed component placement using both methods. We measured component position (inclination, anteversion), procedure time, radiation dose, and usability (System Usability Scale score, Surgical Task Load Index value). Alpha = .05.ResultsCompared with fluoroscopic technique, AR technique was significantly more accurate for achieving target inclination (P = .01) and anteversion (P = .02) and more precise for achieving target anteversion (P < .01). AR technique was faster (mean ± standard deviation, 1.8 ± 0.25 vs 3.9 ± 1.6 minute; P < .01), and participants rated it as significantly easier to use according to both scales (P < .05). Radiation dose was not significantly different between techniques (P = .48).ConclusionA novel 3-dimensional AR guidance system produced more accurate inclination and anteversion and more precise anteversion in the placement of the acetabular component of a hip prosthesis. AR guidance was faster and easier to use than standard fluoroscopic guidance and did not involve greater radiation dose.     

Uncemented Porous Tantalum Acetabular Components: Early Follow-Up and Failures in 613 Primary Total Hip Arthroplasties

Uncemented tantalum acetabular components were introduced in 1997. The purpose was to determine the 2- to 10-year results with this implant material in primary total hip arthroplasty. Our registry identified all primary total hip cases with porous tantalum cups implanted from 1997 to 2004. Clinical outcomes and radiographs were studied. 613 cases were identified. Seventeen percent of patients were lost to follow-up. Twenty-five reoperations were performed (4.4%). Acetabular cup removal occurred in 6 cases (1.2%). No cups were revised for aseptic loosening. Incomplete radiolucent lines were found on 9.3% of initial postoperative radiographs. At 2 years, 67% had resolved. Zero new radiolucent lines were detected. Two- to 10-year results of porous tantalum acetabular components for primary total hip arthroplasty demonstrate high rates of initial stability and apparent ingrowth.     

全髋置换术中髋臼内陷的处理

目的探讨人工全髋关节置换术中髋臼内陷的处理方法及早期疗效。方法 2006年7月至2012年12月,收治继发性髋臼内陷症21例28髋,男12例17髋,女9例11髋;年龄26~68岁,平均56.3岁;原发疾病:类风湿关节炎9例14髋,强直性脊柱炎6例8髋,感染4例4髋(结核和化脓性关节炎各2例2髋),髋臼骨折畸形愈合2例2髋;轻度髋臼内陷6髋、中度髋臼内陷12髋、重度髋臼内陷10髋。患者均行人工全髋关节置换,术中单纯植入生物型臼杯6髋,打压植骨后直接植入生物型臼杯18髋,直接植入骨水泥杯2髋,打压植骨后骨水泥杯固定2髋。结果术后21例28髋切口均一期愈合,无感染及下肢深静脉血栓形成等并发症发生。患者均获随访,随访时间12~78个月,平均42个月。末次随访时,髋关节Harris评分为(87±4.1)分,术前Harris髋关节评分平均(45±3.3)分,较术前有显著差异,优22髋,良6髋,优良率100%。臼杯平均外翻角(42±3.5)°。植骨均骨性融合,无臼杯再次内陷及松动。髋关节活动度增加:屈曲增加(64.3±4.5)°,外展增加(20.5±3.5)°,内旋增加(16.5±2.5)°,外旋增加(19±2.5)°。末次随访时X线片显示所有假体均获得骨性稳定。术前股骨头内陷3~30 mm,平均13 mm;术后股骨头内陷0~5 mm,平均2 mm。人工股骨头旋转中心外移3~28 mm,平均10.5 mm。假体位置良好,无松动、下沉,植骨与髋臼融合,无髋臼再次内陷。结论人工全髋关节置换治疗髋臼内陷时,恢复患髋股骨偏心距及髋臼旋转中心,可获满意早期疗效。     

Standard Versus Custom-Made Acetabular Implants in Revision Total Hip Arthroplasty

BackgroundToday, various options are used for the reconstruction of acetabular bone loss in revision total hip arthroplasty (RTHA). The aim of the study was to compare the outcomes of using standard acetabular implants (SAIs) and custom-made acetabular implants (CMAIs) in RTHA in cases with extensive acetabular bone loss.MethodsThis was a comparative analysis of the results of 106 operations of RTHA performed during the period from January 2013 to December 2019. In 61 cases (57.5%), CMAIs were used. In 45 cases (42.5%), SAIs were implanted.ResultsThe incidence of aseptic loosening of the acetabular component after RTHA in uncontained loss of bone stock of the acetabulum (type III-IV as per the Gross and Saleh classification) using the CMAI was less than that using the SAI (2.4% and 10.0%, respectively). The most significant differences in aseptic loosening rates were noted after implantation of the CMAI and SAI in pelvic discontinuity with uncontained bone defect (0% and 60.0%, respectively; P < .001).ConclusionThe ideal indications for the use of the CMAI are uncontained defects and pelvic discontinuity with uncontained loss of bone stock (types III-V Gross and Saleh classification). Treatment of these defects with the SAI leads to a higher incidence of aseptic loosening requiring re-revisions. Further observation is required to assess the effectiveness of using the CMAI and SAI in the long-term follow-up period.     

Delayed Total Hip Arthroplasty for Failed Acetabular Fractures: The Influence of Initial Fracture Management on Outcome After Arthroplasty

Background

Total hip arthroplasty (THA) provides a successful salvage option for failed acetabular fractures. The complexity of arthroplasty for a failed acetabular fracture will depend on the fracture pattern and the initial management of the fracture. Our objective was to compare the midterm outcome of THA between patients who presented with failed acetabular fractures following initial surgical or nonsurgical treatment.

Effect of Cementless Acetabular Component Orientation,Position, and Containment in Total Hip Arthroplasty for Congenital Hip Disease

We evaluated the effect of the inclination angle, position, and containment of 53 cementless cups inserted in patients with congenital hip disease (CHD), after a minimum of 10 years of follow-up. The polyethylene wear rate was significantly greater when the cup was placed in more than 45° inclination (P = .045) or if the cup was placed lateral to the teardrop position by more than 25 mm (P = .001). Aseptic loosening of the femoral component was significantly greater when the cup was placed more than 25 mm superiorly to the teardrop (P = .049). Cup placement of more than 25 mm lateral to the teardrop affected significantly periacetabular osteolysis (P = .032). In CHD cases, it is preferable to avoid excessive vertical inclination, lateral, and superior placement of cementless cups in an attempt to obtain better containment.     

Bone Preservation in Total Hip Arthroplasty

BackgroundPreserving bone stock in younger and more active patients after total hip arthroplasty (THA) is important for future revision. Newer prosthesis designs, including short femoral stems and isoelastic acetabular cups, are likely to preserve more bone stock. However, long-term follow-up studies on bone remodeling after short-stem THA with an isoelastic monoblock acetabular cup are few. Therefore, we evaluated bone preservation after THA using these prostheses at a 5-year follow-up.MethodsThis prospective observational study is a 5-year follow-up of our previously reported 2-year observational study on the same cohort of patients. We included 45 patients with primary osteoarthritis treated with a calcar-guided femoral short-stem prosthesis and a monoblock press-fit acetabular cup. We evaluated bone mineral density (BMD) around the prostheses using dual-energy X-ray absorptiometry and reported functional outcomes preoperatively and at 3, 12, 24, and 60 months postoperatively. All complications were recorded.ResultsAt the final follow-up, the BMD was comparable with that at 24 months in Gruen zones 3, 4, 5, 6, and 7, whereas it significantly differed in Gruen zones 1 (P < .0001) and 2 (P < .004). On the acetabular side, the BMD leveled off similarly in all DeLee and Charnley zones between 24 and 60 months (P > .05). Moreover, all measured clinical outcomes significantly improved (P < .001). One perioperative dislocation was reported.ConclusionPatients undergoing THA with a calcar-guided femoral short-stem prosthesis and a monoblock acetabular cup can expect preservation of bone stock over a longer follow-up with excellent clinical outcomes and few complications.     

A Comparison of Component Positioning Between Fluoroscopy-Assisted and Robotic-Assisted Total Hip Arthroplasty

BackgroundThis single-surgeon retrospective study examined a consecutive series of direct anterior approach total hip arthroplasties (THAs). Differences for the accuracy of acetabular component placement, leg length discrepancy, femoral offset, and absolute global offset difference were measured for patients who underwent hip replacement surgery with either fluoroscopic or robotic guidance.MethodsOne hundred THAs were included in both the fluoroscopically guided and robotically guided groups in the study. The program TraumaCad was used to analyze the preoperative and 6-week postoperative standing anteroposterior pelvic radiographs used in this study to evaluate the accuracy of component positioning.ResultsRobotic-guided surgery demonstrated a small improvement in acetabular inclination error, 3.8° average robotic error vs 4.63° average fluoroscopic error (P < .01). There was no statistically significant difference in accuracy for acetabular anteversion, leg length discrepancy, femoral offset, or global offset difference between the 2 groups. There was also no significant difference in the placement of acetabular components into the Lewinnek safe zone or Callanan safe zone. Both fluoroscopically guided and robotically guided THA patients had similar patterns of error, with excessive anteversion and inclination being more common than inadequate anteversion or inclination.ConclusionThe findings from our study question the use of haptic robotic guidance during direct anterior approach THA when compared to fluoroscopic guidance.     

The Use of Porous Tantalum Augments for the Reconstruction of Acetabular Defect in Primary Total Hip Arthroplasty

Background

Given the lack of studies of acetabular defect reconstruction in primary total hip arthroplasty (THA) using tantalum augments, this study aims to evaluate clinical and radiographic results for treatment with tantalum augments to reconstruct acetabular defects in primary THA.

Restoration of the Center of Rotation in Revision Total Hip Arthroplasty

We measured the change of the center of hip rotation after the revision of acetabular loosening using an acetabular reconstruction ring and an impaction allogenic bone grafting. Thirty-five revision total hip arthroplasties were performed. The average follow-up was 3.8 years. Horizontal distance was changed from 34.01 ± 10 mm preoperatively to 41.07 ± 6 mm at the latest follow-up. Vertical distance was changed from 32.06 ± 9 mm preoperatively to 20.21 ± 7 mm at the latest follow-up. The Harris hip score was improved from an average of 47 in the preoperative period to 86 at the final follow-up. The restoration of the anatomical hip center has shown to be favorable in terms of functional and radiologic evaluation in total hip revision.     

Causes of Revision in Young Patients Undergoing Total Hip Arthroplasty

BackgroundThe purpose of this study was to identify reasons for revision of total hip arthroplasty (THA) in patients who underwent primary THA at or before the age of 35 years. We hypothesized that the reasons for revision in younger patients would be different from the general older population of patients undergoing THA because of the differences in diagnoses, complexity of deformities, and differences in activity level.MethodsData for 108 hips in 82 patients who underwent primary THA at our institution before the age of 35 years from 1982-2007 and subsequently underwent revision THA were reviewed. Operative reports and clinic notes were reviewed to determine baseline characteristics, reason for revision, timing of revision, and components revised.ResultsThe mean age at index surgery was 25.4 years, and mean time from index to revision surgery was 10.1 years. The most common preoperative diagnoses included avascular necrosis, juvenile idiopathic arthritis, developmental dysplasia of the hip, and posttraumatic arthritis. The most common reasons for revision were acetabular loosening (30.1%), femoral loosening (23.7%), and polyethylene wear (24.7%). 8.3% of patients underwent primary THA with highly cross-linked polyethylene, while the remainder of the patients underwent THA when conventional polyethylene was used. There was no statistically significant association between which component(s) were revised and initial fixation (ie cemented or uncemented prosthesis) (P = .26).ConclusionCauses of revision in this population appear to differ from the general THA population. In young patients, acetabular loosening, femur loosening, and polyethylene wear were the most common causes of revision. Instability and infection were less common compared with literature reports of causes of revision in older patients. Findings in this study may be useful in counseling young patients undergoing THA, though results were likely influenced by the use of conventional rather than highly cross-linked polyethylene in this cohort.     

Intermediate- to Long-Term Results After Hybrid Total Hip Arthroplasty in Patients With Rheumatoid Arthritis

There have been few reports describing intermediate- to long-term results after hybrid total hip arthroplasty in patients with rheumatoid arthritis. We followed up 52 hips in 44 patients aged 5 men and 39 women, with a mean of 11.5 years (range, 5-23.5 years). Revisions had been performed in 6 hips in 6 patients: 1 both acetabular and femoral components for infection, 1 acetabular component for aseptic loosening, 3 acetabular components for recurrent dislocation, and 1 acetabular component for dislodgement of the polyethylene liner from the metal shell. None of other acetabular or femoral components were revised or found to be loose at the final follow-up. Although postoperative dislocation remains a concern, hybrid total hip arthroplasty had an acceptable result in patients with rheumatoid arthritis.