Acetabular and Femoral Component Positioning Using Direct Anterior Approach Versus Posterior Approach in Total Hip Arthroplasty

PurposeDirect anterior approach (DAA) has recently become popular in total hip arthroplasty (THA). However, irrespective of the surgical approach used, component malposition is an important factor affecting function and complications after THA. This study aims to compare component positioning on the femoral and acetabular side between DAA and posterior approach (PA) to the hip joint. We hypothesized that the two approaches are similar in terms of component positioning.MethodsWe prospectively studied 50 patients, matched according to age, sex, and body mass index, undergoing THA, divided non-randomly into 2 groups. Group 1 comprised 25 patients (35 hips) undergoing THA using DAA and group 2 comprised 25 patients (25 hips) undergoing THA using PA. Ten patients from group 1 had simultaneous bilateral THA. Radiological parameters studied were acetabular inclination (AI), coronal femoral stem alignment (CFA), leg length difference (LLD), acetabular cup version (AV), and femoral stem version (FV).ResultsThere was no significant difference in AI, CFA, LLD, AV, and FV between the two groups. Excellent to good inter and intra-observer reliability expressed in terms of intraclass correlation coefficient (ICC) was noted for all the radiographic measurements.ConclusionBoth DAA and PA for THA achieve comparable radiological component positioning. DAA may not provide any advantage over PA in terms of positioning of the prosthesis.Level of EvidenceLevel II, non-randomized comparative study.     

A Comparison of Revision Rates for Dislocation and Aseptic Causes Between Dual Mobility and Large Femoral Head Bearings in Primary Total Hip Arthroplasty With Subanalysis by Acetabular Component Size: An Analysis of 106,163 Primary Total Hip Arthroplasties

BackgroundDual mobility (DM) and large femoral head bearings (≥36 mm) both decrease the risk of dislocation in total hip arthroplasty (THA). There is limited comparable data in primary THA. This study compared the revision rates for dislocation and aseptic causes between DM and large femoral heads and subanalyzed by acetabular component size.MethodsData from the Australian Orthopedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for osteoarthritis from January 2008 (the year of first recorded DM use) to December 2019. All DM and large femoral head bearings were identified. The primary outcome measure was the cumulative percent revision (CPR) for dislocation and for all aseptic causes. The results were adjusted by age, sex, and femoral fixation. A subanalysis was performed stratifying acetabular component diameter <58 m and ≥58 mm.ResultsThere were 4942 DM and 101,221 large femoral head bearings recorded. There was no difference in the CPR for dislocation (HR = 0.69 (95% CI 0.42, 1.13), P = .138) or aseptic causes (HR = 0.91 (95% CI 0.70, 1.18), P = .457). When stratified by acetabular component size, DM reduced the CPR for dislocation in acetabular component diameter <58 mm (HR = 0.55 (95% CI 0.30, 1.00), P = .049). There was no difference for diameter ≥58 mm. There was no difference in aseptic revision when stratified by acetabular component diameter.ConclusionThere is no difference in revision rates for dislocation or aseptic causes between DM and large femoral heads in primary THA. When stratified by acetabular component size, DM reduces dislocation for acetabular component diameter <58 mm.Level of EvidenceLevel III.     

The Direct Anterior Approach for Total Hip Arthroplasty for Severe Dysplasia (Crowe III and IV) Provides Satisfactory Medium to Long-Term Outcomes

BackgroundThe direct anterior approach (DAA) is increasingly used for total hip arthroplasty (THA). Although the DAA can reduce pain, recovery time, and dislocations in nondysplastic hips, few studies report its results in patients with severe dysplasia. We aimed to evaluate outcomes of primary THA through the DAA with cup placement at the true acetabulum in hips with severe dysplasia.MethodsWe retrospectively evaluated 23 consecutive patients (29 hips) who underwent THA by DAA for osteoarthritis secondary to Crowe III-IV dysplasia. Surgical procedures were performed on a traction table, and the acetabular cup was placed in the true acetabulum. Patients were assessed clinically (complications, modified Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, Oxford Hip Score) and radiographically (radiolucencies, subsidence, leg length discrepancies, cup inclination, and cup coverage) at a minimum of 2 years.ResultsOne patient (2 hips) died with original implants (at 13 and 14 years), 3 patients (3 hips) were revised due to wear-induced loosening (at 14, 16, and 18 years), and there were no dislocations or infections. The remaining 19 patients (24 hips) were assessed at 8.4 ± 4.7 years (range 2-20); 2 patients (2 hips) had complications that required reoperation without implant removal. The modified Harris Hip Score improved from 32 ± 9 to 94 ± 7, Western Ontario and McMaster Universities Osteoarthritis Index from 46 ± 18 to 90 ± 7, and Oxford Hip Score was 56 ± 4. Patients were very satisfied (90%) or satisfied (10%). Limb length discrepancy was 2.5 ± 9.0 mm.ConclusionTHA through the DAA with cup placement at the true acetabulum provides satisfactory mid to long-term clinical and radiographic outcomes compared to other approaches for hips with severe dysplasia.Level of EvidenceLevel IV, retrospective cohort study.     

Revision for Aseptic Loosening of Highly Porous Acetabular Components in Primary Total Hip Arthroplasty: An Analysis of 20,993 Total Hip Replacements

BackgroundHighly porous-coated titanium acetabular components have a high coefficient of friction and ultraporous surfaces to enhance bone ingrowth and osseointegration in total hip arthroplasty (THA). There have been concerns with the development of early radiolucent lines and aseptic loosening of highly porous acetabular components. It is unclear whether these concerns relate to a specific implant or the entire class. The aim of this study is to compare the revision rates for aseptic loosening of highly porous acetabular combinations in primary THA using data from a large joint replacement registry.MethodsData were retrieved from the Australian Orthopedic Association National Joint Replacement Registry for the study period September 1999 to December 2019. All primary THA procedures recorded and performed for osteoarthritis using the most common combinations for each highly porous acetabular component with highly cross-linked polyethylene and a 32-mm or 36-mm femoral head were included. The primary outcome measure was revision for aseptic loosening of the acetabular component. Results were adjusted for patient age and gender.ResultsThere were 20,993 primary THA procedures performed for osteoarthritis using a highly porous acetabular component across 6 combinations. Relative to the POLARSTEM/R3 (StikTite), the Exeter V40/Tritanium had a significantly higher risk of revision for aseptic loosening of the acetabular component (hazard ratio 0.21, 95% confidence interval 0.06-0.74, P = .014). There was no difference between any other highly porous acetabular component combination and no late revisions for aseptic loosening.ConclusionHighly porous-coated titanium acetabular components have low rates of aseptic loosening with long-term follow-up. A difference between components may exist.Level of EvidenceLevel III.     

侧卧位直接前方入路全髋关节置换的可行性和效果

目的探讨侧卧位直接前方入路(DAA)全髋关节置换术的可行性和临床效果。方法对307例患者(332髋)行侧卧位DAA全髋关节置换术,评估临床功能,观察影像学结果和并发症。结果单侧髋关节置换手术时间41~73(52.0±5.6)min,术中失血量60~210(94.0±37.4)ml。患者均随访1年。髋关节Harris评分术后1、3、12个月均较术前明显改善(F=237.2,P<0.001)。术后第2天,髋臼假体前倾角为7°~22°(14.4°±6.0°),外展角为26°~57°(43.8°±4.4°)。双下肢长度的差异由术前0~2.5 cm纠正为术后0~1.5 cm(Z=-14.71,P<0.001)。18髋发生股外侧皮神经损伤,3髋发生术中股骨近端骨折,2髋术后早期出现髋关节脱位,1髋髋臼杯未完全打入臼窝,该24例经对症治疗后均愈合、复位良好。术后1年未发生假体周围骨折,无菌性假体松动。结论侧卧位DAA全髋关节置换术安全可行,临床效果良好。     

Intraoperative Complications and Early Return to the Operating Room in Total Hip Arthroplasty Performed Through the Direct Anterior and Posterior Approaches. An Institutional Experience of Surgeons After Their Learning Curve

BackgroundProponents of the direct anterior approach (DAA) for total hip arthroplasty (THA) claim a faster recovery, whereas critics claim an increased risk of early femoral complications. This study analyzed intraoperative and postoperative complications requiring reoperation within one year after THA through the DAA and posterior approach (PA).MethodsA total of 2348 elective, unilateral DAA THAs in patients with osteoarthritis performed between 2016 and 2019 were matched 1:1 for age (±5 years), gender, body mass index (±5), and femoral fixation with 2348 patients who underwent PA THA during the same period. Mixed-effects logistic regression was used. Odds ratios were reported for the occurrence of intraoperative femoral fracture, postoperative femoral fracture, infection, dislocation, and other etiologies requiring reoperation within one year.ResultsIntraoperative femoral fracture occurred in 12 DAA (0.5%) and 14 PA (0.6%) patients. Twenty-five patients (1.06%) in the DAA and 28 (1.19%) in the PA group underwent reoperation within the first year. Reoperations were due to periprosthetic fracture (40%), infection (28%), dislocation (23%), and other (9%). Regression analysis revealed no difference in intraoperative femoral fracture (odds ratio (OR): 0.86, 95% confidence interval (CI): 0.40-1.86, P = .69), postoperative femoral fracture (OR: 1.10, 95% CI: 0.47-2.60, P = .83), infection (OR: 1.50, 95% CI: 0.53-5.23, P = .44), or reoperation within one year for other reasons (OR: 1.50, 95% CI: 0.25-9.00, P = .65). DAA had fewer dislocations requiring reoperation (OR: 0.20, 95% CI: 0.04-0.91, P = .02).ConclusionThis comparative study did not find differences in intraoperative or postoperative fracture or infection between DAA and PA. DAA was associated with a lower likelihood of reoperation for dislocation within one year of surgery.     

Oversized Cups as a Major Risk Factor of Postoperative Pain After Total Hip Arthroplasty

After total hip arthroplasty (THA) some patients have persistent postoperative pain (POP). Some of these POP are anterior and are caused by an anterior iliopsoas impingement (AIPI). We have hypothesized that oversized implanted cups could be responsible for POP and especially AIPI. We screened 237 patients who had a primary THA and compared the size difference (ΔS) between the native femoral head and the implanted cup, in patients with and without POP. Median ΔS was 2 mm [− 6; 11 mm] and patients with POP had a significantly increased ΔS (P < 0.0001). The threshold above which pain was significantly more frequent was ΔS ≥ 6 mm. Odds ratio was 14.4 for POP and 26 for AIPI pain when ΔS ≥ 6 mm.     

Intra-operative referencing technique is non-inferior to use of fluoroscopy for acetabular component positioning in anterior hip arthroplasty

BackgroundIntra-operative fluoroscopy has been shown to improve the accuracy of acetabular component positioning when compared to no fluoroscopy in direct anterior approach (DAA) total hip arthroplasty (THA). Due to logistical reasons, our senior author has been performing DAA THA at one institution without the use of fluoroscopy and has created an intraoperative referencing technique to aid in acetabular component positioning. The purpose of this study is to evaluate the accuracy of acetabular component positioning using fluoroscopy when compared to an intra-operative referencing technique without fluoroscopy.MethodsA total of 214 consecutive primary DAA THA were performed by one surgeon at two institutions and were retrospectively reviewed over a 3-year period. Intra-operative fluoroscopy was used with all patients at Institution A (N = 154). At institution B (N = 60), no fluoroscopy was used, and an intra-operative referencing technique was employed to assist in placement of the acetabular component.ResultsIn the fluoroscopy group, 91% of components met our abduction target, 90% met our anteversion target, and 82.5% simultaneously met both targets. In the non-fluoroscopy group, 98% of components met our abduction target, 92% met our anteversion target, and 90% simultaneously met both targets. There was no difference between groups for placement of the component within both targets simultaneously (p = .171).ConclusionUse of our intra-operative referencing technique is non-inferior in placing acetabular components within a pre-defined safe zone when compared to use of intraoperative fluoroscopy. The intra-operative reference technique can be a helpful adjunct for ensuring accurate acetabular component positioning while simultaneously reducing cost and limiting radiation exposure.     

Direct Anterior Approach for Total Hip Arthroplasty in the Elderly with Femoral Neck Fractures: Comparison with Conventional Posterolateral Approach

BackgroundThe aim of this study was to determine if it was feasible and safe to perform total hip arthroplasty (THA) using the direct anterior approach (DAA) when compared with the conventional posterolateral approach (PA) in patients with femoral neck fractures. The time required to start walking was investigated to identify advantages of the muscle-sparing approach. Safety of the approach was judged based on the incidence and nature of all complications.MethodsWe retrospectively reviewed 67 THA cases due to femoral neck fractures from October 2015 to January 2019. The PA was used in 31 cases, and the DAA was used in 36 cases. The average operative time and amount of bleeding were evaluated. Cup inclination, anteversion, and leg length discrepancy (LLD) were also measured on radiographs. The time to start walking and complications (e.g., intraoperative fracture, infection, and dislocation) were recorded.ResultsThe mean operative time was 84.35 ± 13.95 minutes in PA group and 99.22 ± 20.33 minutes in DAA group (p = 0.010). But after experiencing 20 cases using the DAA, there was no statistically significant difference in the operative time between the groups. The mean volume of bleeding was 428.73 ± 207.26 mL in the PA group and 482.47 ± 150.14 mL in the DAA group. There was no difference in the acetabular cup position between two groups. Ambulation was started at 3.94 days after surgery on average in the PA group and 3.14 days in the DAA group, showing a statistically significant difference. Intraoperative fracture and infection were not observed in either group. The incidence of LLD was 1 in each group. The dislocation rate was 3.2% (1 case) in the PA group and 5.5% (2 cases) in the DAA group.ConclusionsAlthough the DAA for THA was similar to the PA in terms of operative time, volume of bleeding, and complications, the DAA showed a great advantage in early rehabilitation as a muscle-sparing procedure in the elderly with femoral neck fractures.     

髋臼骨折内固定失败术后的全髋关节置换术

目的:探讨髋臼骨折内固定失败术后继发创伤性关节炎和(或)股骨头缺血性坏死行全髋关节置换术的特点及临床疗效。方法:2009年2月至2014年10月,采用全髋关节置换术对31例(31髋)髋臼骨折内固定失败继发创伤性关节炎和(或)股骨头缺血性坏死患者进行治疗,其中男26例,女5例;受伤时平均年龄(41±12)岁。患者因髋臼骨折内固定术后3~132个月,平均(20.6±26.9)个月内继发创伤性关节炎和(或)股骨头缺血性坏死而行全髋关节置换术,全髋关节置换术均采用后外侧入路。观察术后并发症和关节活动度,并比较术前和术后随访时髋关节VAS疼痛评分和Harris髋关节评分。结果:术后27例获得随访,随访时间12~80个月,平均(43.2±11.7)个月。其中出现关节感染1例,假体松动1例,脱位1例,无继发坐骨神经损伤病例发生。所有随访病例髋关节功能和步态有明显改善;至末次随访时,VAS由术前平均(7.6±1.2)分,降低到术后平均(1.2±0.9)分,Harris评分由术前平均(45.5±13.6)分,提高到术后平均(88.5±7.8)分,差异均有统计学意义(P0.01)。髋关节除后伸外,前屈、外展、内收、内旋及外旋活动范围较术前显著增加,差异有统计学意义(P0.05)。X线片复查示:髋臼假体无不稳定发生,1例股骨柄假体下沉3 mm,2例发生异位骨化。结论:正确处理内固定物,提防潜在感染,合理重建髋臼骨缺损,是髋臼骨折内固定失败术后全髋关节置换成功的关键。     

Long-Term Outcomes After Metal-on-Metal Total Hip Arthroplasty With a 28-mm Head: A 17- to 23-Year Follow-Up Study of a Previous Report

Background

Second-generation, metal-on-metal total hip arthroplasty (MoM THA) using a 28-mm head has shown favorable results compared with large head MoM THA. The purpose of this study is to evaluate the long-term outcomes of cementless primary MoM THA with a 28-mm head and the incidence of osteolysis using computed tomography.

全髋关节置换术治疗成人髋关节发育不良的髋臼重建

目的探讨全髋关节置换术治疗成人髋关节发育不良（DDH）时不同方式髋臼重建对疗效的影响。方法 2000年1月至2007年10月,36例（44髋）先天性髋臼发育不良患者进行了全髋关节置换。年龄42～65岁,平均48岁。术前Harris评分平均为49.9分,双下肢长度差异平均为1.8 cm,髋关节平均活动度：屈曲59.6°,外展21.6°,内收13.9°,外旋10°,内旋8.2°。术中臼杯均安装于真臼处,髋臼内移14髋,髋臼内陷成形术18髋,自体股骨头结构性植骨12髋。髋臼侧均选用非骨水泥型假体。疗效评价：根据Harris评分分为优、良、可、差四级。结果所有患者均获得随访,随访时间1.8～9.2年,平均5.1年。平均Harris评分由术前的49.9分恢复到术后的90.1分,两者比较有统计学差异（P〈0.01,t=28.807）,其中评定为优23髋、良17髋、可4髋,术后优良率达90.9%。术后髋关节平均活动度：屈曲105°,外展35°,内收15.8°,外旋45°,内旋15°。本组病例无肺栓塞、深静脉血栓形成、感染等并发症发生。X线检查示假体无松动移位,无翻修病例。结论全髋关节置换术治疗成人髋臼发育不良采用恰当的髋臼重建结合非骨水泥型髋臼假体可获得满意中远期疗效。     

非骨水泥臼杯加自体股骨头植骨全髋关节置换术治疗髋臼发育不良伴骨性关节炎

目的：评价非骨水泥臼杯加自体股骨头植骨的全髋关节置换术治疗髋臼发育不良继发骨性关节炎的结果。方法：回顾性分析20例(21髋)患者行全髋关节置换术治疗髋臼发育不良继发骨性关节炎。女性18例,男性2例,平均年龄50岁,采用非骨水泥臼杯加自体股骨头植骨螺钉固定重建髋臼侧。臼杯置于真性髋臼水平,所有病例由于髋臼缺损而需要行自体股骨头植骨。平均植骨块覆盖的臼杯比例为31％(10％～45％)。8髋植骨块覆盖小于25％,13髋位于25％-50％之间。平均随访时间4．7年(1．5—8年)。采用改良Harris评分对结果进行评估。术前及随访时进行摄片观察。结果所有植骨块均获得愈合。无植骨块塌陷和髋假体松动。改良Harris评分由术前平均46分增加到89分。术前除1例双髋发育不良外,下肢不等长均超过2cm,术后只有2例仍有双下肢不等长超过1cm。3髋的植骨块外侧非支撑臼杯部分出现轻微的骨吸收。3髋发现有BrookerⅠ度异位骨化,1髋Ⅱ度异位骨化。结论：使用非骨水泥臼杯加自体股骨头植骨重建髋臼侧的全髋关节置换术治疗髋发育不良继发骨性关节炎可获得良好结果。该方法在植骨块支撑臼杯不超过50％的情况下,髋臼固定可靠,可保留髋臼的骨量。     

Bipolar hip arthroplasty for avascular necrosis of femoral head in young adults

Background:Bipolar hip arthroplasty (BHA) is one of the options for treatment of avascular necrosis (AVN) of the femoral head. Acetabular erosion and groin pain are the most allowing for gross motion between the common complications. We propose that these complications are secondary to improper acetabular preparation allowing for motion between the BHA head and the acetabulum.Results:The mean followup was 7.52 years (range 4-16 years). The HHS significantly improved from a preoperative value of 39.3 (range, 54-30) to a postoperative value of 89.12 (range 74-96). According to HHS grades, the final outcome was excellent in 52 hips, good in 28 and fair in 16 hips. Hip and groin pain was reported in four hips (5%), but did not limit activity. Subsidence (less than 5 mm) of the femoral component was seen in 8 cases. Subgroup analysis showed patients with Ficat Stage 3 having better range of motion, but similar HHS as compared to Ficat Stage 4 patients.Conclusion:Bipolar hip arthroplasty (BHA) using tight fitting cup and acetabular reaming in AVN hip has a low incidence of groin pain, acetabular erosion and revision in midterm followup. Good outcome and mid term survival can be achieved irrespective of the Ficat Stage.     

Crowe IV 型髋关节发育不良全髋关节置换术前计算机辅助设计

 目的 探索采用计算机辅助技术, 对接受全髋关节置换(total hip arthroplasty, THA)的 Crowe IV型髋关节发育不良患者进行术前评估, 确定髋臼大小、骨缺损程度, 并在此基础上辅助手术设 计、假体选择及骨缺损修复。 方法2011 年3 月至10 月, 共10 例(13 髋)Crowe IV型高位脱位髋关节发 育不良患者接受THA 治疗。患者均为女性;年龄32~74 岁, 平均42 岁。所有患者术前行髋关节三维CT 扫描, 然后将扫描数据输入SuperImage 软件重建骨盆及髋臼。重建后在不同角度精确评估真臼位置, 测 量真臼大小及前后柱厚度, 评估骨缺损程度;将髋臼试模、骨缺损修复材料(钽金属垫块)按1颐1 大小扫 描输入计算机系统, 进行术前模拟安放, 确定髋臼假体大小、安放位置;髋臼假体安放后评估遗留的骨缺 损, 确定骨缺损修复材料, 进行骨缺损修复模拟测试。 结果 9 例(12 髋)术中实际安放髋臼假体型号与 术前计算机辅助设计一致, 1 例(1髋)假体型号较术前设计大一号。所有患者髋臼安放位置与术前计划 一致, 均安放于真臼。髋臼骨缺损修复按术前设计:4 髋因髋臼顶部骨缺损明显(臼顶部骨性覆盖 < 70%), 采用钽金属垫块修复骨缺损, 以增强髋臼的稳定性;7 髋采用Harris 法自体股骨头植骨修复骨缺 损;2 髋髋臼杯植入后臼顶覆盖可, 术中未植骨。 结论 对Crowe IV型髋关节发育不良者行计算机辅助 下THA术前设计, 有助于术前精确评估真臼发育情况、大小及髋臼骨缺损, 提高手术治疗精确性。     

全髋关节置换术治疗髋臼骨折继发创伤性髋关节炎和股骨头坏死中远期疗效观察

目的 :评价全髋关节置换术治疗髋臼骨折后继发创伤性髋关节炎或股骨头坏死的中远期疗效。方法 :2000年1月至2005年12月,对33例髋臼骨折继发创伤性髋关节炎和(或)股骨头坏死患者实施全髋关节置换术。其中男21例,女12例;年龄27~69岁,平均52岁。23例骨折曾行切开复位内固定术,前侧入路5例,后侧入路12例,混合入路6例;10例行保守治疗。髋关节置换术均采用后外侧入路,术前髋臼骨折均已愈合,术中完全去除内固定5例,去除部分内固定3例,植骨20例。6例术中使用骨水泥假体,27例使用生物型假体。观察术中情况和术后并发症,比较术前Harris髋关节评分和术后10年评分,以假体松动、骨溶解或翻修为终点的生存分析显示假体10年生存率。结果:所有患者获随访,术后10年死亡1例,随访时间平均12年(10~15年),术后10年时Harris髋关节评分较术前升高。1例假体早期无菌性松动行翻修术,2例骨溶解形成合并假体无菌性松动并行翻修术治疗,单纯骨溶解无假体松动1例,术后深静脉血栓4例,假体脱位2例,切口感染和假体周围感染各1例。假体10年生存率为84.8%(28/133)。结论:全髋关节置换术治疗髋臼骨折后继发创伤性髋关节炎或股骨头坏死能明显改善患者的髋关节的功能,并有较高的假体生存率,具有良好的中远期疗效,是一种有效的治疗手段。     

Minimum 10-Year Results of Cementless Ceramic-On-Ceramic Total Hip Arthroplasty Performed With Transverse Subtrochanteric Osteotomy in Crowe Type IV Hips

BackgroundTotal hip arthroplasty (THA) performed for developmental dysplasia of the hip is a technically difficult procedure with a high complication rate, especially in the presence of completely dislocated hips. This study aimed to evaluate at least 10 years of follow-up results of cementless, ceramic-on-ceramic (CoC) THA performed with transverse subtrochanteric osteotomy in Crowe type IV hips.MethodsWe retrospectively reviewed 50 patients’ 67 hips that underwent CoC, cementless THA with transverse subtrochanteric osteotomy between 2008 and 2011. Clinical and radiological data of the hips were examined. Clinical results were evaluated using the Harris Hip Score and the Western Ontario and McMaster Universities Osteoarthritis Index.ResultsThe mean Harris Hip Score improved from 22.9 ± 9.9 preoperatively to 94.1 ± 8.1 at the final follow-up (P < 0.001). The median Western Ontario and McMaster Universities Osteoarthritis Index score improved from 72 (interquartile range: 17) preoperatively to 2 (interquartile range: 17) postoperatively (P < 0.001). The preoperative mean leg length discrepancy was improved from 4.9 ± 1 cm to 1.5 ± 1 cm in unilateral cases at the last follow-up (P < 0.001). Revision surgery was required because of nonunion in two patients, prosthetic infection in one patient, and aseptic femoral loosening in the other patient. The overall ten-year survival rate was 94% for femoral stems and 98.5% for acetabular components as per Kaplan-Meier survival analysis.ConclusionTransverse subtrochanteric shortening osteotomy combined with using cementless acetabular and femoral components with a CoC bearing surface promises successful clinical results and high prosthesis survival in the treatment of Crowe IV hips at long-term follow-up.     

变异髋臼初次全髋人工关节置换术前设计及临床意义

目的:探讨变异髋臼初次全髋人工关节置换术中髋臼假体的正确放置位置及手术疗效。方法:对34例（38髋）接受全髋关节置换的髋臼变异的各类髋关节疾病进行术前设计,其中男20例,女14例,平均年龄56.1岁（29⁷5岁）。股骨头坏死继发骨性关节炎15例（19髋）,髋臼发育不良继发骨性关节炎12例,创伤性骨关节炎5例,髋关节融合术后1例,髋关节人工股骨头置换术后1例。结果:术后患者均获得随访,平均随访11个月（5³8个月）。根据Harris髋关节功能评分评定,优（>90分）12髋,良（80⁹0分）23髋,尚可（70⁷9分）3髋,失败0髋（<70分）。评定结果:术前Harris评分平均47.9分,术后平均90.3分。结论:对于髋臼解剖结构异常的髋关节疾病患者行全髋人工关节置换时,通过术前对髋臼正确位置的设计,使髋关节中心置于正确的位置上,既可简化术中操作的难度,又可以使臼杯假体得到牢固固定及良好的骨覆盖,有利于人工全髋关节的长期疗效。     

Highly Porous Tantalum Acetabular Components Without Ancillary Screws Have Similar Migration to Porous Titanium Acetabular Components With Screws at 2 Years: A Randomized Controlled Trial

BackgroundIt is proposed that highly porous coatings on acetabular components, such as a porous tantalum coating, provide adequate fixation without ancillary screw fixation in primary total hip arthroplasty (THA). However, tantalum acetabular components have been associated with higher rates of revision than other uncemented components in national registries. The aim of this randomized controlled trial is to determine whether the early migration of a solid-backed tantalum acetabular component was no greater than that of a titanium acetabular component with ancillary screw fixation that has proven good clinical results.MethodsSixty-six patients aged 40 to 64 years, with osteoarthritis and Charnley grade A or B activity grade and who underwent primary THA, were recruited into the trial. Patients were randomized intraoperatively to receive either the tantalum or titanium acetabular component. All patients received the same cemented polished tapered femoral stem, 28-mm cobalt-chromium femoral head, and highly cross-linked polyethylene liner. Acetabular component migration was measured using radiostereometric analysis at 4-6 days postoperatively and at 6 weeks, 3 months, 1 and 2 years following THA.ResultsThe mean proximal migration at 2 years for the tantalum cohort was 0.17 mm (95% confidence interval, 0.09-0.24) which was no greater than that of the titanium cohort which was 0.19 mm (0.07-0.32). Harris hip scores and functional activity scores were similar between groups.ConclusionThese results demonstrate that early stability can be achieved without ancillary screw fixation through the use of a highly porous high friction coating on a solid-backed modular acetabular component.Level of EvidenceLevel I.     

EOS Imaging is Accurate and Reproducible for Preoperative Total Hip Arthroplasty Templating

BackgroundTemplating is a critical part of preoperative planning for total hip arthroplasty (THA). The accuracy of templating on images acquired with EOS is unknown. This study sought to compare the accuracy and reproducibility of templating for THA using EOS imaging to conventional digital radiographs.MethodsForty-three consecutive primary unilateral THAs were retrospectively templated, six months postoperatively, using preoperative 2D EOS imaging and conventional radiographs. Two blinded observers templated each case for acetabular and femoral component size and femoral offset. The retrospectively templated sizes were compared to the sizes selected during surgery. Interobserver agreement was calculated, and the influence of demographic variables was explored.ResultsEOS templating predicted the exact acetabular and femoral size in 71% and 66% of cases, respectively, and to within one size in 98% of cases. The acetabular and femoral component size was more likely to be templated to the exact size using EOS compared to conventional imaging (P < .05). The femoral component offset choice was accurately predicted in 83% of EOS cases compared to 80% of conventional templates (P = .341). Component size and offset were not influenced by patient age, gender, laterality, or BMI. Interobserver agreement was excellent for acetabular (Cronbach’s alpha = 0.94) and femoral (Cronbach’s alpha = 0.96) component size.ConclusionsPreoperative templating for THA using EOS imaging is accurate, with an excellent interobserver agreement. EOS exposes patients to less radiation than traditional radiographs, and its three-dimensional applications should be explored as they may further enhance preoperative plans.