Bone dynamics of the acetabulum in experimental subluxation of the hip joint and its repair process

Subluxation of the hip and subsequent acetabular dysplasia were experimentally produced by fixing the knee of young rabbits in extension position. Changes of the acetabulum during the repair process after reduction were investigated radiologically, histologically and histomorphometrically. Radiologically, subluxation and acetabular dysplasia appeared two weeks after fixation and disappeared as the knee became flexible after removal of fixation. Histologically, abnormalities of growth cartilage and hypertrophy of trabeculae in the secondary spongiosa were prominent two weeks after fixation. Histomorphometrically, the bone area, osteoid surface and mineral appositional rate increased at this time. The above findings, however, were normalized as concentric reduction of the hip was achieved. Abnormal stress acting on the acetabulum caused hypertrophy of trabeculae, and this may result in the development of osteoarthritis. In order to prevent such a pathologic process, it is important to normalize the hip mechanically from the view point of bone dynamics.     

髋臼骨折手术治疗后髋关节功能恢复的影响因素分析

背景：髋臼骨折多为高能量损伤所致,属于关节内骨折,手术是最佳治疗方式。但骨折类型、手术入路、复位质量、年龄、手术时机等会对治疗效果产生影响。因此,分析影响手术效果的关键因素十分必要。目的：探讨手术治疗髋臼骨折后影响髋关节功能恢复的因素。方法方法：选择2010年1月至2013年10月手术治疗且随访资料完整的髋臼骨折患者42例,18例采用Kocher-Langenbeck入路,14例采用髂腹股沟入路,10例采用前后联合入路。术后采用Matta标准评定骨折复位情况。采用改良的Merled＇Aubigne-Postel评分系统评价患者髋关节功能。对可能影响手术疗效的指标（如性别、年龄、手术时机、骨折类型、手术入路、复位质量等）进行单因素及多因素Logistic回归分析,筛查影响手术疗效的危险因素。结果：术后14例达到解剖复位,20例良好复位,8例一般复位。切口均甲级愈合,未出现感染。全部患者术后随访12-26个月,平均19个月。X线检查示骨折于术后10-18周愈合,平均14周。术后出现坐骨神经损伤4例,创伤性关节炎2例,股骨头缺血坏死2例,异位骨化7例。术后6个月时髋关节功能评定为优13例,良21例,可5例,差3例,优良率为81%。单因素分析结果显示性别、年龄、手术入路、髋关节脱位与手术疗效无明显关系（P〉0.05）,而手术时机、骨折类型、复位质量、异位骨化与手术疗效有关（P〈0.05）。多因素分析显示骨折类型、手术时机、复位质量是影响手术效果的独立因素（P〈0.05）。结论：骨折类型、手术时机和复位质量是影响髋臼骨折手术疗效的独立因素,而后两者是相对可控的因素,治疗时要选择合适时机、尽量达到解剖复位,以期获得良好的临床结局。     

人工髋关节置换术后髋臼松动的重建方法

由于人工臼杯的松动、移动，邻近人工关节的髋臼壁发生各种各样的骨缺损，翻修时如何能够得到人工关节的初期坚强固定和长期的支持变得非常困难。我们应用同种冷冻保存骨和人工骨，在植骨的同时应用髋臼钢板加强固定。1996年10月-2006年3月共收治17例18侧单独髋臼翻修术患，[第一段]     

Significance of the lateral epiphysis of the acetabulum to hip joint stability

Normal development of the acetabulum is crucial to the growth and stability of the hip. Twenty-five New Zealand White rabbits (postweaning) weighing 1.5-2.2 kg were used. Both hips were exposed through an anterolateral approach. On the right hip, a fixed area of superolateral physeal cartilage was damaged with drills. Sham open reduction was performed for the left hip. Radiographic changes of the right hips were evident at 6 weeks. At 12 weeks, the right hip dislocated in a posterior and superior direction. The left hip remained normal. Histopathologic analysis correlated strongly with the radiographic findings. There were thinning of cartilage cells of the acetabulum, with disorganization. The acetabular roof was poorly formed. The lateral acetabular epiphysis is vital to the development of the acetabular roof. Damage to this epiphysis may result in acetabular maldevelopment and subsequent hip instability. We tested the hypothesis that abnormality in this epiphysis can give rise to abnormal acetabular development.     

髋臼骨折合并髋关节脱位的手术治疗

[目的]探讨髋臼骨折的分型、手术入路、内固定方式及手术疗效.[方法]2001年11月～2006年8月,本院手术治疗的髋臼骨折合并股骨头脱位34例,根据髋臼骨折的AO分类标准:A型骨折24例,B型骨折10例,应用Kocher-Langenbeck(KL)手术入路20例,Gibson入路2例,KL改良入路4例,髂腹股沟入路4例,前后联合入路4例,内固定方式32例选用螺钉及钢板,2例应用钢丝环扎固定.[结果]所有患者获平均37.6个月随访.参照美国骨科学会(AAOS)提出的评价标准[1]:优12例,良12例,可4例,差6例,优良率为71%.[结论]结合全面的影像学资料,正确判断髋臼骨折的AO分型,恰当的手术入路及合适的内固定方式,同时注意手术时的微创操作及骨折复位的质量,才能提高疗效,减少并发症.     

Treatment of chronic osteomyelitis of the acetabulum after hip joint replacement with a glutaeus maximus muscle flap

Summary We report on a 65-year-old man who was sent to our clinic with osteomyelitis of the hip combined with a chronic external fistula after hip joint replacement followed by several further operations including amputation of the leg. After complete removal of the fistula and repeated vacuum sealing of the wound, we used a vasculated glutaeus maximus muscle flap to close the defect. The course after the operation was without any complications. The method applied led to sufficient treatment of the osteomyelitis without weakening the trunk muscles or rendering the use of crutches more difficult.      

An experimental analysis of three-dimensional hip joint force after pelvic osteotomies

A three-dimensional analysis of the resultant forces on the hip was carried out using a fresh cadaver of a 40 year old male. A cross sectional area of each of twenty-four muscles around the hip was measured. Markers were fixed at the proximal and the distal insertions of the muscles and the direction of muscular forces was calculated. From these data, three-dimensional resultant forces on the hip and muscular forces around the hip were calculated through the computer in the normal and the postoperative states of Salter pelvic osteotomy, Chiari pelvic osteotomy and rotational acetabular osteotomy. The results showed the resultant forces to be 3.38 times the body weight in the normal specimen, and 3.79 times for the Salter pelvic osteotomy, 2.74 times for the Chiari pelvic osteotomy, and 4.07 times for the rotational acetabular osteotomy. However, as the loaded area on the femoral head also had increased to 1.12 times for the Salter pelvic osteotomy, and 1.20 times for the rotational acetabular osteotomy, the resultant force in each square centimeter was 0.94 times for the Salter pelvic osteotomy, and 0.71 times for the rotational acetabular osteotomy.     

Size and direction of hip joint forces associated with various positions of the acetabulum

When total hip replacement is performed, the position of the acetabular component may affect wear and component survival time. We considered the questions: In what way does displacement of the hip joint center alter (1) the magnitude and (2) the direction of the resultant force? Biomechanical tests were carried out on a human multibody model. After displacement of the hip joint center, the resultant forces were calculated for the single leg stance. With the flexed single leg stance, maximum hip joint forces were observed with lateral, cranial, posterior displacement. The peak forces were affected by the modeling of a gluteus maximus wrapping point at the ischial tuberosity and were overestimated when this was removed. With the straight single leg stance, posterior displacement decreases the total load on the hip joint because of the increased leverage of the rectus femoris. With regard to the direction of the resultant force, medial displacement increases the angles in both planes, cranial displacement increases it in the sagittal plane (cranial, posterior-caudal, anterior), and anterior displacement decreases the angle in the sagittal plane and increases it in the frontal plane (medial, cranial-lateral, caudal). The direction of the force is relatively insensitive to displacement of the hip joint center. The results presented here indicate a marked increase in the force after lateral, cranial, posterior displacement of the center in the flexed single leg stance. To avoid extreme joint loading and to reduce the wear after total hip arthroplasty, the cranial and posterior regions of the acetabulum should be fully reconstructed. A high hip joint center has an adverse effect on the magnitude of the force, although the directions are hardly affected by it.     

Total hip arthroplasty after fracture of the acetabulum. Long-term results

We made a retrospective study of 55 primary total hip arthroplasties in 53 patients with a history of previous acetabular fracture. The mean follow-up was 7.5 years and the average age at fracture was 48.7 years. The incidence of radiographic femoral loosening (29.4%), symptomatic loosening (15.7%), and femoral revision (7.8%) were similar to those previously reported at 10 years for routine arthroplasties by Stauffer (1982). On the acetabular side, the incidence of radiographic loosening (52.9%), symptomatic loosening (27.5%), and revision (13.7%) were four to five times higher. We conclude that a history of prior acetabular fracture has a significant adverse impact on the long-term outcome of any subsequent total hip arthroplasty.     

Total hip arthroplasty after arthrodesis of the hip joint

The results of 15 conversions of a hip arthrodesis into a total hip arthroplasty performed in the years 1980-1995 are reported. Fifteen patients (8 men, 7 women) underwent total hip arthroplasty 30.9 (range 2-61) years after spontaneous or operative fusion of a hip joint. The primary indications of the conversion were low-back pain (n = 10), knee pain (n = 2) and hip problems (n = 3). At follow-up examination 5.4 (range 2-13.3) years postoperatively, the Harris Hip Score averaged 86.0 (range 70.1-99.0). Six patients were pain-free, 7 had less pain, 2 felt no improvement of pain. All patients confirmed that they would undergo the operation again. The Trendelenburg sign was negative or mild in 8 patients and moderate to severe in 7. Aseptic loosening of 2 stems (1 cemented, 1 cementless) and 2 deep infections required revision surgery. We conclude that this operation can lead to satisfactory results even after a long duration of the arthrodesis. However, full function with no pain and a negative Trendelenburg sign could be obtained in only 20% (3/15) of the cases.     

髋臼骨折合并髋关节后半脱位的诊断和治疗

自1996年至今,我院共收治髋臼骨折并髋关节后半脱位病人8例.由于此症在临床上尚未见报道,再加上临床症状不典型,X线片诊断率低,时常发生漏诊及误诊,现报道如下,以引起足够重视.     

Total hip arthroplasty after hip joint ankylosis

Background

Back pain and knee pain are typical secondary degeneration symptoms after hip ankylosis. Take down of hip ankylosis and implantation of a total hip arthroplasty (THA) is believed to be a promising treatment option.

Methods

A total of 22 hip ankylosis patients [15 men, mean age 53.7 years (range 30–72 years); 7 women, mean age 50.8 years (range 42–61 years)] underwent THA during 1980–2000 after spontaneous (n = 10) or surgical (n = 12) fusion of the hip joint. The mean duration of ankylosis prior to THA was 32.5 years (range 2–61 years).

Results

At the mean follow-up of 13.2 years (range 2–19 years), the Harris hip score averaged 84.9 points (range 70.1–99.0 points). All patients (100%) confirmed that they would undergo conversion surgery again. Aseptic loosening of two stems (one cemented, one cementless; 9.5%) and two deep infections (9.5%) required revision surgery.

Conclusions

THA is a promising option for treatment of secondary long-term hip ankylosis sequelae. A conversion operation after spontaneous ankylosis provides better functional outcome than after surgical fusion. However, full function with complete pain relief and a negative Trendelenburg sign might be not attainable in all cases.