【专题文献】之人工髋关节置换——全髋关节置换疼痛的评估

【专题文献】之人工髋关节置换

全髋翻修讲座之一：全髋关节置换疼痛的评估 By: 宋兵乙
全髋翻修讲座之二：髋关节翻修术中内植物的取出 By: 宋兵乙
全髋翻修讲座之三：髋关节翻修术中髋臼失败的重建和翻修 By: 宋兵乙
全髋翻修讲座之四：髋关节翻修术中股骨失败的重建和翻修 By: 宋兵乙
全髋翻修讲座之五：全髋关节置换术后髋关节脱位的处理 By: 飘洋过海
全髋翻修讲座之六：全髋关节置换术假体周围感染的处理 By: shiitake
全髋翻修讲座之七：下肢假体周围骨折的处理 By：宋兵乙

MINI-SYMPOSIUM: REVISION HIP SURGERY
小讲座：髋关节翻修术之一

(i) Evaluation of a painful total hip replacement
全髋关节置换疼痛的评估

Ardeshir Y Bonshahi Anil K Gambhir
Abstract
Total hip replacement is a common and effective operation with a high success rate. This article discusses the aetiology and evaluation of persisting pain after total hip replacement. A thoroughhistory and physical examination and appropriate investigation can determine the cause of the painful total hip replacement in most patients, allowing appropriate treatment.
摘要：
全髋置换术是常见的和有效手术，成功率高。本文论述了全髋关节置换疼痛的病因学并对疼痛进行评估。在很多病例中，病史、物理检查和恰当的研究可以确定全髋关节置换疼痛的原因，因而可以适当的治疗。


Introduction
In the US alone, it has been estimated that nearly 600 000 hip replacements and 1.4 million knee replacements will be performed in the year 2015.1 Long term results for Total Hip Replacement (THR) are excellent; it is a procedure that is successful in reducing pain and improving function and quality of life in patients with debilitating hip disease, and it is regarded as one of the most cost-effective interventions in health care.2,3
Patient expectation to a large extent predicts post operative satisfaction. Mancuso et al4 found that 60% of patients expected pain relief and those who wanted to return to nonessential activities were least satisfied (75%). A small proportion of patients continue to experience pain, some with no obvious cause, making these cases difficult to treat. Britton et al5 suggest the use of pain scores as the main outcome measure after THR, as postoperative pain remains one of the most sensitive predictors of success. They studied the natural history of pain after THR in more than 2000 patients and confirmed a large improvement in pain in the first six months, followed by a further small improvement for the next two years. After four years there was a gradual, sustained deterioration in pain levels.

引言：
仅在美国，在2015年估计每年有60万例髋关节置换（THR）和140万例全膝置换手术[1]。THR的长期随访结果是优良的，该手术对于髋部疾病的患者，能减轻疼痛、改善功能、提高生活质量，在卫生行业被视为最具性价比的干预之一[2，3]。
病人的期望在很大程度上预测了术后满意度。Mancuso[4]等发现60%的病人期待疼痛减轻，那些希望能返回非必须活动的病人满意度最小（75%）。少部分病人仍然感到疼痛，一部分没有明显原因，因而治疗困难。Birtton等[5]建议使用疼痛指数作为主要结果来衡量全髋术后，因为术后疼痛仍然是最敏感的成功预测指标之一。他们研究了超过2000例病人THR术后疼痛自然进程，证实了在最初的6个月疼痛有很大改善，在随后两年进展较小。在四年之后，疼痛级别逐渐的持续的恶化。



History
A detailed history and physical examination is important to narrow the differential diagnosis and allow more focused investigations. It is important to note the nature of pain, its onset, duration, frequency, site, relieving and exacerbating factors. Pain similar to that felt preoperatively might suggest that the original diagnosis/pathology, for which the THR had been performed was in error and other causes of the pain should be excluded. If the pain is different from that felt pre-operatively then a cause related to the surgery is more likely. Persistent pain with no pain free interval suggests infection, fracture, impingement or, in the case of uncemented prostheses, failure of initial stability. Late onset pain is seen in aseptic loosening, low grade infection, osteolysis or instability. Constant pain, rest and night pain is suggestive of sepsis or malignancy. Pain brought on by starting to walk from sitting - start up pain - is indicative of prosthetic loosening, but activity related pain relieved by rest suggests neurogenic or vascular claudication , bursitis, iliopsoas tendinitis or loosening.
The site of the pain is important; pain localized to the greater trochanter can be due to trochanteric wires, bursitis or non union. Groin pain is often related to acetabular problems but occasionally is due to inguinal hernia or iliopsoas irritation. Occasionally deep gluteal pain arises from acetabular loosening, but is more commonly associated with lower back, sacroiliac joint or neurogenic problems especially combined with radicular pain. The latter should be distinguished from thigh pain or referred knee pain which may be indicative of femoral loosening. In particular, loosening at the tip of the stem, if it is in contact with posterior femoral cortex, can cause pain felt at the back of the thigh. However, some patients with a well fixed cemented or cementless stem can still experience thigh pain for no apparent reason.
As well as noting any precipitating cause of the pain such as trauma or a fall which might indicate a fracture or the onset of loosening, factors related to the surgery must be sought as delayed wound healing, postoperative haematoma formation, persistent wound ooze, prolonged inpatient stay or antibiotic administration and distant sites of infection may indicate joint sepsis. Co-morbidities such as obesity, diabetes, rheumatoid arthritis and immuno-suppression are common in infection and in female patients any relationship between the pain and menses, such as can occur with endometriosis and other gynaecological conditions, should be noted.
Obviously previous hospital records including operation details (surgical approach, implants etc) should be reviewed to gather as much information as possible.

历史：
详细的病史和物理检查对于缩小鉴别诊断和更集中的调查是很重要的。记录疼痛的特征、起始、持续时间、频率、部位和减轻和加重因素是很重要的。疼痛和术前相似，可能提示由原始诊断/病因而导致的全髋置换可能是错误的，需要排除引起疼痛的其他病因。如果疼痛和术前不同，可能和手术相关性更大。持续性疼痛，没有间隔，提示感染、骨折、撞击或非骨水泥假体初始稳定性的丧失。迟发疼痛见于无菌性松动、低度感染、骨溶解，或不稳。经常性疼痛，休息或夜间疼痛，提示脓毒或肿瘤。起立痛－疼痛诱因为坐位起立去行走，指示假体松动，疼痛和活动相关，休息减轻提示神经或血管性跛行，滑囊炎，髂腰肌肌腱炎或松动。

疼痛部位是重要的。疼痛局敢于大转子的原因为转子钢丝，滑囊炎或骨不连。腹股沟痛常常和髋臼问题相关，但偶而可因为腹股沟疝或髂腰肌激惹。偶然臀深部疼痛由髋臼松动引起，但更常和下腰背、骶髂关节、神经原性问题特别是伴发神经根痛疼痛等因素相关。后者应该可以从大腿疼痛或可能是股骨松动涉及的膝痛来鉴别。尤其是，股骨假体干顶部的松动，如果它接触股骨皮质的后侧，能引起大腿后侧疼痛。然而，有些病人具有固定良好的骨水泥或非骨水泥型假体干，仍然发生大腿痛而没有明显原因。
正如应当考虑记录的任何直接的疼痛原因如创伤、可能导致骨折的摔倒、松动开端、手术相关因素等，而伤口延迟愈合，术后血肿形成，持续伤口渗出，延长住院日，抗生素的使用和远处感染等可能提示脓肿的情况也要考虑。感染常见于共存疾病如肥胖、糖尿病、类风湿关节炎和免疫抵制性疾病，女性病人的疼痛和月经的任何相关性，如子宫内膜异位和其他妇科疾病应被记录。
应该回顾尽可能多的明确即往住院史包括手术细节（手术入路，内固定物等）。






Examination
The clinical examination begins by observing the patients gait and looking for abnormalities, such as antalgic, Trendelenburg (which may be related to abductor deficiency after a direct lateral approach) or short limb gait.6 Leg length discrepancy should be measured with the patient standing on graduated blocks until the pelvis is level in order to determine true and apparent leg length discrepancy, seen with pelvic obliquity and scoliosis. Progressive leg shortening may be related to the subsidence of one of the components.7
The skin is inspected for scar location, sinuses and inflammation or swelling around the hip and is palpated to localize areas of tenderness, such as that due to trochanteric bursitis or underlying neuromas.
Range of movement is assessed, paying particular attention to any pain provocation. Pain at an extreme of movement may be related to impingement or loosening, whereas pain throughout the range of movement may indicate an inflammatory process or infection. Pain on resisted flexion is suggestive of iliopsoas tendinitis. The examination should include the ipsilateral knee and a neurovascular examination of both lower limbs.

检查
临床检查从观察病人步态、寻找畸形开始，其他如止痛药，Trendelenburg征（反映直接外侧切口后外展肌无力）或短肢步态。肢体长度不一致应该当测量病人站立有递增的砖块上直到骨盆在真实水平，明显肢体长度不一致可见骨盆倾斜和脊柱侧凸。渐进的肢体短缩可能和某一组件下沉和关。
检查皮肤疤痕位置，窦道，炎症，髋周包块和触诊疼痛区域，如转子滑囊炎和深部神经瘤。
活动范围需要估计，特别注意任何疼痛激发试验。疼痛在极度的关节活动时可能与撞击或松动有关。然而疼痛在活动范围中自始至终可能提示炎症过程或感染。在髋关节抵抗屈曲时疼痛提醒髂腰肌肌腱炎。检查应该包括同侧膝和双下肢神经血管检查。




Differential diagnosis
Possible causes of a painful total hip replacement can be divided into intrinsic and extrinsic: (Table 1)
鉴别诊断
引起全髋置换疼痛的可能病因分为内在病因和外在病因（见表1）

Intrinsic causes：
Aseptic loosening: This accounts for more than 70% of the hip revisions in Sweden8 and it is important to know what prosthesis was used, as some designs are associated with early failure. Among the most dramatic reports of early stem failure is that of the Capital THA (3-M Healthcare Limited, Loughborough, UK). Definite loosening was present in 16% with an additional 8% possibly loose at follow-up of 26 months. Approximately 5,000 stems were implanted throughout Great Britain with a failure rate at 5 years estimated at 20%.9
Loosening is usually asymptomatic in the early stages, particularly on the acetabular side. Late presentation may be as groin or thigh pain and sometimes as deep gluteal discomfort in cases of acetabular loosening (Figure 1).

内在病因：
无菌性松动：在瑞典70%的髋翻修的原因为无菌性松动，知道使用的假体类型很重要，有一些假体设计导致早期失败。其中早期股骨干假体失败的最引人注目的报道是Capital全髋（英国3-M公司）。在26个月的随访中，其明确的松动率为16%，另外有8%为可能松动。在英国大概有5000例股骨干假体植入，5年的失败率估计在20%[9]。
松动在其早期通常是无症状的，特别是髋臼松动。后期表现可能为腹股沟或大腿疼痛，有时，髋臼松动表现为臀深部不适（见图1）。

图1：右髋置换术后疼痛，鉴别诊断无菌骨溶解或感染。髋关节抽吸显示没有细菌。一步法行全髋翻修减轻了疼痛。







Infection: Deep infection is a challenging complication for both the patient and the surgeon. The incidence of infection post joint arthroplasty ranges from 0.3%, reported by the British Medical Research Council10 to 2.2% described in a large review.11 Fitzgerald et al12, classified prosthetic joint infections:
_ Stage I Acute fulminating infections, usually presenting within six weeks
_ Stage II Delayed sepsis or chronic indolent infection
_ Stage III Late haematogenous infection in a previously well functioning hip replacement.
Tsukayama et al13 proposed a fourth type where a positive culture is found at the time of revision without previous evidence of infection.
In a large study the most frequently isolated organisms were coagulase negative staphylococci (47% patients) and methicillin sensitive staphylococcus aureus (MSSA, 44% patients). 8% grew methicillin resistant staphylococcus aureus (MRSA) and 7% grew anaerobes.14

感染：深部感染对于病人和医生来讲都是挑战性的并发症。英国医学研究委员[10]在一项大范围回顾中报道，关节置换术后感染率在0.3%－2.2%[11]。Fitzgerald[12]等对关节假体感染进行分型：
I型：急性暴发性感染，通常发生于6周内
II型：延迟脓毒症，或慢性无痛性感染
III型：之前良好功能的髋关节置换迟发血源性感染
Tsukayama 等[13]提出了第IV型：在髋关节翻修前没有感染证据，但翻修时培养结果阳性。
大量研究显示最常见的单发菌种为凝固酶阴性葡萄球菌（47%的病例）和甲氧西林敏感金黄色葡萄球菌（44%的病例）。8%转为耐药金葡菌，7%转为厌氧菌[14]。






Instability: Dislocation is one of the most common complications of total hip arthroplasty. The reported incidence varies from 0.3% to 7% in primary total hip replacement and up to 25% in revision hip replacement. While frank dislocation of the hip is obvious from the history and radiographs, subluxation is less obvious. It is related to cup position, wear or deficient abductor mechanism. It can produce discomfort from soft-tissue stretch, and may be associated with mechanical clunking.
Early dislocation occurs within the first 3 months postoperatively and carries a better prognosis and a lower rate of recurrence with non operative treatment compared to late dislocation.15 In comparison, late dislocations have a multifactorial aetiology including polyethylene wear and soft-tissue laxity which in turn leads to a higher recurrent dislocation rate.2,16 Larger femoral heads have reduced the incidence of dislocation by increasing the head-neck ratio thus improving the primary arc of motion and by allowing a greater amount of translation before dislocation occurs.17

不稳：脱位是全髋置换最常见的并发症之一。报道显示初次全髋置换的脱位发生率在0.3%－7%之间，而全髋翻修的脱位率上升到25%。根据病史和放射学表现，髋关节完全脱位很明显，而半脱位则不明显。脱位和髋臼位置、颗粒和不足的外展肌力有关。脱位因软组织张力产生不适，可能会有机械碰撞声。

早期脱位发生在术后最初的3个月内，此类型能更好的诊断，使用非手术治疗比迟发脱位再脱位率较低。相对的，迟发脱位包含多种原因，如聚乙烯颗粒，软组织松弛并最终导致较高的再脱位率[2，16]。较大的股骨头通过增加头颈比率因此在脱位发生之前提高了初始活动弧和更大范围的移动而减少了脱位次数[17]。



Periprosthetic fractures: Berry reported an periprosthetic fracture incidence of 0.3% in 20 859 primary cemented and 5.4% in 3121 uncemented total hip arthroplasties and an intraoperative fracture rate of 3.6% in cemented and 20.9% in uncemented revision total hip arthroplasties.18 The location of the fracture and bone quality needs careful evaluation. The Vancouver classification is based on fracture location
Type A the fracture involves the trochanteric region
Type B the fracture is around or just distal to the femoral stem
B1 the femoral implant is well fixed B2 the femoral implant is loose but the remaining bone stock is good
B3 severe bone stock loss in the presence of a loose implant.19
Type C the fracture is so far below the stem that the treatment is independent of the hip replacement.
假体周围骨折：
Berry报道假体周围骨折发生率，20859例初次骨水泥型全髋发生率0.3%，而非骨水泥型全髋3121例发生5.4%,骨水泥型全髋翻修术中骨折发生率在3.6%，而非骨水泥型全髋翻修术中骨折发生率在20.9%[18]。骨折部位和骨质量需要仔细评估。Vancouver分型是基于骨折部位。
A型：骨折包括转子区。
B型：骨折围绕或正位于股骨干假体远端。
B1：股骨假体固定稳定。 B2股骨假体松动但骨量尚好。B3 严重骨量缺损表现出假体松动。[19]
C型：骨折位于股骨干假体下部，治疗方式同全髋不相关。






Inflammatory conditions: Trochanteric bursitis is reported to occur in 17% of arthroplasties performed with a trochanteric osteotomy and in 3% without, and can result from increasing the offset in the operated hip or from trochanteric wires.20 The pain is well localized and increases upon lying on the affected side. Iliopsoas tendonitis can arise from impingement with the leading anterior edge of a relatively under anteverted or retroverted cup.
炎症情况：据报道关节置换术后转子滑囊炎的发生率，在转子截骨术时为17%，没有截骨时为3%。逐渐增加的手术侧髋关节的偏移或转子部位钢丝可引起滑囊炎[20]。疼痛局限，在患侧卧位时疼痛加重。髂腰肌肌腱炎可由假体领前缘和相对前倾或后倾的髋臼杯撞击而发生。

Thigh pain - tip of stem pain: The aetiology of thigh pain is multifactorial and it has a variable reported incidence. Engh and Massin noted an 8% incidence of thigh pain in patients with bony ingrowth and 35% with fibrous ingrowth.21 There are two basic aetio-pathogenic mechanisms, tip micromotion and tip overload. In the former, stem loosening or fibrous fixation allows tip of stem movement during cyclic loading of the joint which in turn irritates the densely innervated endosteum. The latter is due to a mismatch in the modulus of elasticity between a stiff, largediameter uncemented femoral implant and the surrounding, less stiff host bone. Here the stem does not transmit the applied load to the femur along its full length, but concentrates it around the tip producing excessive bone localized strain and endosteal irritation.
大腿疼痛－股骨干假体顶端疼痛：大腿痛的病因学是多因素的，各报道的发生率不同。Engh和Massin记载在骨向内长入时大腿痛的发生率为8%，而纤维长入时其发生率为35%[21]。有两种基本的致病机制，股骨假体顶部微动或超负荷。前者，股骨假体松动或纤维固定，允许假体顶部在关节圆周负荷时移动，这依次刺激稠厚的神经支配的骨内膜。后者，由于在坚硬的大直径非骨水泥股骨假体和其周围坚强度较低的宿主骨之间的弹性模量不匹配。因此，股骨干假体不能沿股骨全长传导适用的负荷，但是集中在假体顶部产生过度的骨局限性压力和骨内膜刺激。

Extrinsic causes of pain
If the pain experienced after hip replacement is similar to that experienced before, then it is likely that hip pathology may not have been the cause of symptoms. For example, lumbar spine and sacroiliac pathology can mimic symptoms of an arthritic hip, giving rise to thigh, buttock and occasionally groin pain. Spinal stenosis is one of the common differential diagnoses; passive hip movements in such cases should be pain free, but occasionally pre-existing spinal stenosis is unmasked by increased patient activity levels after THR, but such pain is of a different character from that experienced preoperatively.
Other degenerative and inflammatory spinal or sacro-iliac joint problems can be differentiated by a detailed history and examination, and can be confirmed with radiographs, computed tomography, or magnetic resonance imaging. However, in some cases it is difficult to exclude a spinal contribution to pain based on examination and investigation alone and diagnostic local anaesthetic hip injection may be useful.
Pain also may be related to Paget’s disease which can coexist with osteoarthritis of the hip (Figure 2). It can produce postoperative pain but should respond well to medical management.
The femoral, sciatic and lateral cutaneous nerves of the thigh can be injured either directly at operation or indirectly by limb lengthening due to the hip replacement giving rise to causalgia. Metastatic disease affecting the pelvis, lumbar spine, or femur can give symptoms suggestive of a malfunctioning painful THR. Such metastases may not be evident on plain radiographs and may be obscured by implants. They have a typical history of rest or night pain.
外在病因：
如果关节置换术后疼痛与术前相似，这看起来髋关节病因并没有引起疼痛症状。举个例子，腰椎和骶髂部病因所致症状和髋关节炎的症状类似，发生大腿、臀部疼痛，偶而腹股沟区疼痛。椎管狭窄是最常用的鉴别诊断之一。这部分病例中髋关节活动障碍应该是无痛的，但是偶而合并的椎管狭窄，在全髋置换术后逐渐增加病人的活动度后才会被发现。但是这样的疼痛具有不同于术前的特征。
其他退变性、脊柱炎症、或骶髂关节问题，能根据详细的病史和检查鉴别，也能由放射学、CT或MRI检查证实。然而，在有些病例中，基于检查和研究来排除脊柱原因的疼痛是困难的，诊断性局部麻醉药髋部注射可能有帮助。
疼痛也可能和Paget病有关，该病能和髋关节骨关节炎共存（见图2）。该病能产生术后疼痛，但应该对医学治疗敏感。
股神经、坐骨神经和股外侧皮神经能在术中直接损伤或由全髋置换导致的肢体延长而间接损伤，产生皮肤灼痛。骨盆、腰椎或股骨折肿瘤转移性疾病能产生症状，使人误认为全髋功能不良和疼痛。这样的转移疾病可能在放射学上没有证据，可能由于内固定物而致认识不清。此种情况有经典的休息痛或夜间痛病史。

图2：左髋置换术后疼痛，大转子痛，异位骨化或疼痛来自潜在的Paget病？

Investigation
Blood tests: Routine blood tests including a full blood count and inflammatory markers, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are essential.
However, the leucocyte count is not particularly helpful in diagnosing infection. Canner et al22 reported an elevated leucocyte count in only 15% of cases with confirmed prosthetic infection. Spangehl et al23 too reported an elevated leucocyte count to be a poor indicator of infection, with a sensitivity of 20%, a specificity of 96%, a positive predictive value of 54%, and a negative predictive value of 85%.
ESR is a non specific marker of inflammation. After an uncomplicated THR it decreases to less than 20 mm per hour at approximately 6 months. Patients with a documented infection of a prosthesis had a significantly higher ESR (mean 60 mm/hour).24 The CRP level returns to normal more rapidly than ESR after total hip arthroplasty . Aalto et al25 recorded that the CRP peaked at postoperative Day 2, and was normal after 3 weeks. Thus an elevated CRP after that may be indicative of infection. A combination of a normalESRandCRP has a specificity of 100%for excluding the diagnosis of infection in patients with a painful THR.26

检查：
血化验：血常规包括完整的血细胞计数和炎症标记物，血沉和C反应蛋白CRP这是必须的。
然而，白细胞计数在诊断感染时并不是特别有帮助。Canner 等[22]报道白细胞计数升高在证实的假体感染中仅占15%。Spangehl等[23]也报道白细胞升高是感染的一个较差的指标，敏感率仅在20%，特异性96%，阳性预测(价)值54%，阴性预测价值85%。
血沉是一种非特异性炎症标记物。在一个不复杂的全髋术后大概6个月，血沉下降到20mm/h以下。有既往假体感染病史的病人有显著的血沉升高，平均在66mm/h[24]。在全髋术后，CRP水平恢复到正常比血沉更快。Aalto等[25]报道CRP在术后第二天到达峰值，术后3周恢复正常。因此，在那之后升高的CRP可能提示感染。正常的ESR和CRP，可以排除全髋关节置换疼痛的感染诊断，其特异性为100%[26]。




Plain radiography: All patients should have an AP and a lateral X Ray of the affected hip. Evaluation of serial x-rays is more informative than a single image in assessing signs of loosening.
Cemented implants are assessed for the presence of radiolucencies in the bone cement interface around the stem and acetabular components. The acetabulum was divided into three zones by DeLee and Charnley27 and the femur has been divided into seven zones by Gruen.28 The development of progressive radiolucent lines in these zones either in cemented or uncemented components suggests loosening. This should be differentiated from age related radiolucent lines, which do not have an area of adjacent sclerosis, and non-progressive radiolucent lines typically in femoral zones 1 and 7 due to imperfect cement interlocking was not associated with adverse outcome.29
X线片：所有病例的患髋均应摄前后位和侧位X线片，判定松动征兆，评估一系列的X线片比单一图片信息量大。

骨水泥内植物通过股骨假体和髋臼假体周围的骨－骨水泥界面的放射可透性的存在来判断。Delee和Charnley[27]将髋臼划分三个地带，Gruen[28]将股骨分布七个区域。不管骨水泥还是非骨水泥型假体，在这些区域逐渐增加的放射透亮带提示松动。这应当与年龄相关的放射透亮带相鉴别，后者没有邻近区域的硬化。由于不完美的骨水泥内锁，导致很典型的位于1和7区的非进展的放射透亮线，但和不良后果不相关[29]。


Cemented femoral stem loosening was classified by O’Neill and Harris30
Possible loosening is defined as a radiolucent line at the bonecement interface occupying between 50% to a 100% of the whole bone-cement interface.
Probable loosening is defined as a radiolucent line that is either continuous around the entire cement mantle or is 2 mm in width at some point.
Definite loosening is defined as component migration, cement or component fracture.

Cemented acetabular component loosening was classified by Hodgkinson et al31 depending on the extent of demarcation at the bone cement interface.
Type 0 had no radiolucencies
Type 1 involved the outer third
Type 2 involved the outer and middle third
Type 3 had complete demarcation
Type 4 had a migrated socket.
This correlated with intraoperative findings of loosening; none of the type 0 sockets, 7% of type 1, 71% of type 2, 94% of type 3 and 100% of type 4 sockets were loose.

O'Neill和Harris将骨水泥型股骨干假体松动分类[30]：
可能存在的松动：射线透亮带位于骨－骨水泥界面，占整个骨－骨水泥界面的50－100%。
可能的松动：放射透亮带是连续围绕于整个骨水泥套，或在某些位置有2mm宽度。
明确的松动：假体位移，骨水泥或假体骨折。

骨水泥型髋臼组件松动由Hodgkinson等[31]依据骨－骨水泥界面的分界范围分类：
0型：没有放射透亮带
1型：外1/3
2型：外和中1/3
3型：完全分界
4型：臼移位
这和松动的术中所见相关。0型的没有松动，7%的1型，71%的2型，94%的3型，100%的4型松动。












Engh et al32 predicted cementless component stability by major and minor radiographic signs. Major signs of osseointegration are absence of reactive, radio dense lines around the porous-coated portion of the implant and the presence of endosteal ‘spot-welds’. Minor signs of osseointegration include absence of pedestal or calcar atrophy and a stable distal stem. Anextensive reactive line around the porous coated portion of the implant is a major sign of failure of osseointegration, whereas the absence of endosteal spot welds is considered aminor sign.

Infection can be difficult to diagnose radiographically in the early stages. Rapidly progressive osteolysis within the first year of a total hip replacement is highly indicative of infection and periosteal new bone formation, endosteal scalloping and osteolysis are late changes highly suggestive of infection.33
Engh等[32]通过主要的和次要的放射学指征预测非骨水泥型假体稳定性。材料与骨结合主要指征是缺乏活力，放射高亮线环绕在假体多孔涂层周围，骨内膜表现出点状结合。材料与骨结合次要指征包括缺乏基底或股骨距萎缩，稳定的股骨假体远端。在假体涂层周围非广范的反应线是假体失败的一个主要信号，而缺乏骨内膜的点状结合现像被认为是微不足道的指征。

感染早期阶段使用放射学诊断很困难。全髋置换术后最初一年内快速进展的骨溶解是感染的强指标，骨膜新骨形成，骨内膜扇贝壳样，和最后变化的骨溶解高度提示感染[33]。



Nuclear Medicine: There is enhanced uptake of Technetium-99 methylene diphosphonate (99Tc MDP) in metabolically active bone apparent as localized hot spots-a positive bone scan. Increased uptake is seen in aseptic loosening, infection, heterotopic bone formation, stress fractures, tumours, metabolic bone disease, and reflex sympathetic dystrophy.34 However, increased uptake is seen for up to two years after uncomplicated THR,35 which reduces the value of this investigation in evaluating suspected loosening or infection in its early stages. In a series of 54 patients with painful hip arthroplasties who had surgical exploration, Lieberman et al36 reported that technetium bone scanning had a lower sensitivity and specificity than serial plain radiographs for diagnosing femoral and acetabular component loosening and they recommended using bone scanning only when plain radiography was inconclusive. Technetium-99 methylene diphosphonate scan is most useful as a negative predictor, asd if normal it eliminates of many of the potential hip related causes of pain.
Merkel et al37 have shown that indium 111-labeled (111In) leucocyte scans have a higher sensitivity and specificity for excluding infection than 99Tc MDP or Gallium scan, either alone or in combination. Thus if infection is suspected an indium labelled white cell scan is usually performed following a positive technetium bone scan.

核医学： 有代谢活力的骨骼有99Tc MDP增强吸收，表现为局部热点阳性骨扫描。吸收增加发生于无菌性松动，感染，异位骨化，应力骨折，肿瘤，代谢性骨疾病，反应**感神经营养不良[34]。然则，吸收增加在不复杂的全髋置换术后两年以上然后存在[35]，因而减小了早期阶段的可疑松动或感染的评估价值。在一系列54例全髋术后疼痛而使用手术探查的病例中，Lieberman等[36]报道相对于股骨和髋臼组件松动而使用的放射诊断，骨扫描敏感性和特异性较低。作者推荐骨扫描仅仅在放射学在无确定结果的情况下使用。99Tc MDP骨扫描是最有价值阴性预测指标，如果结果正常则排除了很多疼痛的潜在髋关节相关病因。
Merkel 等[37]证实相对于99Tc MDP或镓扫描，111In白细胞扫描对于排除感染有更高的敏感性和特异性，不管是单独还是联合使用。因此，如果怀疑感染，在阳性的锝扫描之后，通常需要做铟标记的白细胞扫描。


Hip aspiration/anaesthetic injection: Hip aspiration should be performed in all suspected cases of infection and should be offered to patients with an elevated ESR and CRP beyond the early post operative period i.e. after 3 months. We perform these under image intensifier guidance in theatre combined with an arthrogram to confirm the intra-articular location of the needle in case of a dry tap. In such cases, some authors recommend instilling sterile saline and re-aspirating it for microbiological investigation.38 Spangehl et al.39 reported that aspiration had an 89% probability of confirming infection if the ESR and CRP level were both elevated.
One advantage of aspiration is the ability to inject local anaesthetic in case of a dry tap. It can help localize intrinsic versus extrinsic causes of pain which is particularly helpful if hip and lumbar spine pathologies coexist.
髋关节抽吸/麻醉药注射：所有怀疑感染的病例应当做髋关节抽吸，也应当建议那些血沉和CRP升高超过术后早期阶段比如说术后3个月的病人做抽吸。我们执行那些在影像增加器的引导下联合关节X线照片去证实穿刺针位于关节内的位置以免干抽。在这样的病例中，一些作者推荐慢慢滴入无菌盐水和再次抽吸，进行微生物学检查[38]。Spangehl等[39]报道如果血沉和CRP都升高，抽吸有89%的可能性能证实感染。
抽吸术的一个好处是注射局部麻醉药以免干抽，它能帮助定位内在对外在的疼痛病因，如果髋关节或脊柱病因复合存在，这特别有帮助。

Computed Tomography (CT): CT scanning has been described to assess loosening in an apparently radiographically stable cementless femoral stem.40 The CT scan is obtained with the leg in maximum internal rotation and then repeated with it in maximum external rotation. Using the posterior femoral condyles as a reference, a change in position of the component between the two views greater than 20 is strongly indicative of loosening.
CT：有文献描述了CT扫描去评价那些明显的放射学稳定的非骨水泥型假体的松动情况[40]。对腿部最大内旋的CT扫描，然后最大外旋进行重复扫描。使用股骨后髁作为参照，在两种视图之间假体位置变化大于20强烈提示松动。

Summary
Painful THR can be a diagnostic challenge and a systematic approach using an algorithm can be helpful (Table 2). While mechanical loosening may not be a diagnostic challenge, even in such cases a high index of suspicion for infection is essential. History, examination, plain radiographs, and blood tests including ESR, and CRP are the mainstays of the workup for sepsis. Hip aspiration should be attempted in the case of elevated or equivocal markers. Bone scans are rarely necessary to confirm the diagnosis. Surgical exploration to establish the diagnosis is rarely useful and can leave the patient even more distressed. If no known cause is established in spite of thorough evaluation, then a period of observation with serial radiographs is recommended.

概要
全髋关节置换疼痛是个诊断的挑战，一个系统化处理方法使用规则算法可能会有帮助（见表2）。力学松动可能不是诊断难题，甚至在这些病例中，高度怀疑感染是必须的。病史，物理检查，X线片，血液检测包括ESR和CRP，是诊断脓毒症的主要依据。髋关节抽吸应当在那些升高的或意义不明的指标时施行。骨扫描很少是证实诊断的必须步骤。手术探查确定诊断很少有用，能使病人更苦恼。尽管彻底的评价后，如果病因仍然未知，此时推荐一个阶段的放射学观察。