Accurate limb-length equalization during total hip arthroplasty

A method of equalization of limb lengths during total hip arthroplasty (THA) was developed that uses the concept of precise reproduction of the position of the femur in space (abduction/adduction) by use of a carpenter's level. Precise reproduction of the femoral position allows accurate measurement of the distance between the pelvis and femur before hip dislocation and after trial component placement allowing accurate measurement of the change in the distance between the femur and pelvis. Accordingly, limb length can be maintained or adjusted to match the contralateral side with increased accuracy. A prospective study was performed with 117 consecutive patients undergoing THA to assess the accuracy of an intraoperative limb-length measuring device. Patients were sequentially randomized into two groups. Group A patients underwent THA without the use of the measuring device, and group B underwent THA using the device. Radiographic assessments of limb lengths were measured using the method of Williamson and Reckling. The hips in group B had a statistically significant decrease in limb-length inequality after THA compared with group A (P<.01). Average postoperative limb-length inequality was 8.8 mm and 3.4 mm for groups A and B, respectively. Three (5%) of 58 group B patients and 18 (31%) of 59 group A patients had a radiographic postoperative limb-length inequality >12 mm (P<.01). Eighty-four of group B patients had limb lengths within 6 mm of the contralateral side compared with 30% of group A patients. Twenty-four percent of group A patients and 7% of group B patients had a symptomatic limb-length inequality that required a heel lift (P<.01).     

A simple method to minimize limb-length discrepancy after hip arthroplasty

Background Limb-length discrepancy is not uncommon after total hip arthroplasty. To minimize such discrepancies, we introduced a simple method to select an appropriate modular head during surgery.

Patients and methods We used this method in 45 hips, and compared the outcome with that of a historical control group of 47 hips. Both groups received cement-less femoral components with modular heads of 4 different neck lengths. In the study group, we calculated the ideal distance between the center of the modular head and lesser trochanter on a preoperative AP radiograph. During surgery, we measured the actual distance between the center of trial heads and the lesser trochanter with a ruler, and selected the head in which the measured distance was closest to this distance. In the control group, we had selected a modular head based on preoperative planning.

Results The study group had a smaller mean postoperative limb-length discrepancy (2 (SD 2) mm) than the controls (7 (SD 4) mm).

Interpretation This simple technique reduces limb-length discrepancy after cementless total hip arthroplasty.     

Correction of limb-length inequality during total hip arthroplasty

Although several methods of intraoperative limb-length measurements have been described, their success in predicting the limb-length correction is not well documented. A new technique of measuring intraoperative limb lengthening using a vertical Steinmann pin at the infracotyloid groove of the acetabulum was studied in 100 consecutive primary total hip arthroplasties. Correlation of the predicted intraoperative correction was done with the postoperative radiographic measurements. Preoperative limb-length inequality ranged from -24 mm (short) to +2 mm (long) (mean, -4.2 mm). Intraoperative measurement of lengthening ranged from 0 to 15 mm (mean, 5.9 mm). Radiographic measurements of postoperative radiographs showed lengthening ranging from 0 to 17 mm (mean, 7.4 mm). There was significant correlation between the 2 values (r =.84). Postoperative limb-length inequality ranged from -7 mm to +8 mm (mean, 1.9 mm). None of the patients had to use shoe lifts for equalization of limb lengths.     

Leg-length discrepancy after total hip arthroplasty

Leg-length discrepancy after total hip arthroplasty can pose a substantial problem for the orthopaedic surgeon. Such discrepancy has been associated with complications including nerve palsy, low back pain, and abnormal gait. Careful preoperative measurement and assessment, as well as preoperative and postoperative patient education, are important factors in achieving an acceptable result. However, after total hip arthroplasty, equal leg length should not be guaranteed. Rather, the patient should be given a realistic assessment of what can reasonably be expected.     

Effect of preoperative limb-length discrepancy on abductor strength after total hip arthroplasty in patients with developmental dysplasia of the hip

Background

Limb-length discrepancy (LLD) arising from hip subluxation or dislocation and accompanied by insufficiency of hip abductor in patients with developmental dysplasia of the hip (DDH) can be corrected partially or completely with total hip arthroplasty (THA). However, information about post-THA changes in abductor strength related to preoperative LLD in patients with DDH is lacking. We aimed to explore the post-THA recovery course of abductor muscle strength and its related factors in patients with DDH.

Methods

A cohort of 45 patients with unilateral DDH was divided into two groups according to their Crowe classification: patients with class I or II DDH formed Group M, and patients in class III and IV DDH formed Group S. The following parameters were measured on standardized antero-posterior hip radiographs taken in the supine position pre- and post-THA: abductor muscle length, abductor lever arm, LLD, and femoral offset (FO). Abductor strength was evaluated quantitatively with the Isomed 2000 isokinetic test system (1 week before the operation and 1, 3, 6, and 12 months after the operation). The contralateral normal hip joint served as a within-patient control. The affected side:healthy side ratios of the parameters above were calculated.

Results

Abductor strength ratio evaluated at the five follow-up time points was larger in Group M than that in Group S (p < 0.001). The average abductor strength ratio reached 78.5, 85.4, and 89.2 % at the 3, 6, and 12 months postoperative exams, respectively, in Group M, and reached 50.3, 63.2, and 72.9 % in Group S. The abductor muscle length ratio, the abductor muscle level arm ratio, and the FO ratio were significantly increased postoperatively, relative to preoperative assessment, in the two groups. LLD was reduced significantly postoperatively, relative to preoperative values, in both groups. Both preoperative LLD (r = ?0.791, p < 0.001) and the change in abductor muscle length ratio (r = ?0.659, p < 0.001) correlated with abductor strength recovery.

Conclusion

Patients showed the greatest improvement in abductor strength within the first 6 months after THA, especially during the first 3 months. Abductor strength was consistently greater in patients with mild dysplasia than in patients with severe dysplasia. The extent of preoperative LLD and the increase in abductor length were related with post-THA abductor strength recovery in patients with DDH.     

全髋关节置换术后肢体不等长预防和治疗

肢体不等长(LLD)是全髋关节置换术的常见并发症之一,以肢体延长多见,近期可造成患者关节或神经疼痛不适,远期可能因代偿性骨盆倾斜或脊柱侧弯而导致腰背痛、跛行及假体无菌性松动.根据髋关节骨结构完整与否,LLD可分为真性不等长和功能性不等长.植入假体选择不当和术者操作经验欠缺是造成LLD的主要原因.术前仔细测量评估并选择合适的模板、术中运用测量装置能有效减少LLD发生率.目前国内外对于LLD的治疗尚无统一标准,主要通过增高鞋垫或鞋跟的非手术方法来矫正.翻修手术仅适用于极少数患者.     

全髋关节置换术下肢长度测量及术后不等长处理

全髋关节置换术(THA)常见并发症之一双下肢不等长及其相关并发症极大地影响THA术后效果及患者满意度.术前下肢长度测量是THA术前设计的重要步骤,也是术中均衡双下肢长度的重要依据;术后测量则为手术效果作出评估,方法包括体检测量、模板测量及各种影像学基础上测量.目前临床上尚无一种公认的准确性高、重复性好的术中下肢长度测量方法,L形测径器为术中测量器的改良,更符合实际,其主要对术前、术中测量结果进行综合评估,但双下肢不等长难以完全避免,测量方法有待进一步研究.术后肢体严重不等长或出现神经麻痹等重要症状者需行积极处理,可考虑翻修手术.该文对下肢长度测量方法及术后不等长处理的研究进展作一综述.     

全髋置换术下肢不等长的预防

目的探讨全髋置换术下肢不等长预防方法.方法对50侧（56髋）行全髋置换术,在股骨转子下垂直打入第1枚克氏针（股骨颈骨折者先复位）, 在该针纵轴线相对应的髂嵴上打入第2枚克氏针,测量两针之间的距离.股骨柄假体在试模时将髂嵴上和股骨转子下克氏针插回去, 再次测量两针之间的距离与原先比较,差距用不同尺寸的柄颈和头作相应的调整.结果 50例（56髋）术后经平均1.8年的随访,患者日常生活自理,均不扶拐.两下肢等长48例,相差2.0 cm以内2例.结论该方法实用,疗效较好,有一定的推广价值.     

Leg length discrepancy in total hip arthroplasty.

After conducting a thorough literature review, we realized that no consensus exists regarding the definition of a significant postoperative inequality. Whereas some investigators quantitate the disparity, accepting as much as 2.0 cm or in some cases less, others define a significant disparity as one that promotes adverse functional effects postoperatively. This lack of a consistent definition reflects the wide disparity of opinion regarding the problem of postoperative leg length inequalities in total hip surgery. Although the literature may lack consistency, it does reflect the collective experience of many surgeons and provides valuable insight when approaching the issue of limb lengths in reconstructive surgery of the hip. We offer the following suggestions: 1. Begin with a thorough history and physical examination. Question the patient as to whether he or she actually perceives a leg length inequality. 2. Be aware of apparent leg length discrepancies in patients with hip disease. The perceived limb shortening is usually the result of a fixed adduction contracture with little true shortening. 3. Develop a consistent approach of evaluation preoperatively, intraoperatively, and postoperatively. Employ reliable and convenient clinical measures and radiographic techniques. A method of intraoperative assessment is mandatory. 4. Redundancy in the system helps to minimize error. Good preoperative planning does not supplant the need for intraoperative assessment and vice versa. 5. Address the issue of offset in preoperative planning. Anticipate its misleading effects on intraoperative evaluation. 6. Mention potential inaccuracies regarding limb length reconstruction in total hip surgery as part of a routine preoperative evaluation. Patients' expectations should be high but temporized with realism.     

Instability following total hip arthroplasty

Dislocation is the second most common complication of total hip arthroplasty. Most dislocations occur early in the postoperative period and are caused by patient factors, surgical factors, or a combination of both. Patient factors that predispose to postoperative dislocation include previous surgery and neurologic impairment. Surgical factors include surgical approach, component orientation, and prosthetic and/or bony impingement. Evaluation of patients undergoing total hip arthroplasty requires a thorough history and physical examination, as well as a detailed radiographic assessment. Closed treatment of instability is successful in two thirds of cases; the remainder require surgical management. Surgical techniques used to treat or minimize risk of further dislocation include revision arthroplasty, trochanteric advancement, use of elevated rim liners, and use of constrained liners.     

Rhabdomyolysis following total hip arthroplasty

We report six cases of contralateral limb involvement during total hip arthroplasty including swelling of the gluteal muscle compartments, rhabdomyolysis, myoglobinuria, and sciatic nerve palsy. The risk factors for such complications include obesity, prolonged operative time, and positioning in the lateral decubitus position. The laboratory and clinical findings are consistent with a gluteal muscle crush-injury with consequent compartment syndrome. The patients should be treated conservatively as symptoms can be expected to resolve.     

Dislocation following total hip arthroplasty

Summary The rate of postoperative dislocation after Stanmore total hip arthroplasty in 427 cases was 4.9%; 1.4% were classified as recurrent cases. Retroversion of the acetabular component and postoperative joint laxity were the only factors that were found to predispose to dislocation. The importance of preserving the effective femoral neck length during total hip arthroplasty is emphasized.

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Zusammenfassung Die postoperative Luxationsrate nach Implantation einer Stanmore-Hüftgelenk-Totalprothese betrug in 427 Fällen 4,9%, wovon 1,4% wiederkehrende Luxationen darstellten. Eine Retroversion der Prothesenpfanne and eine postoperative Weichteillaxität im Hüftgelenkbereich waren die einzigen Faktoren, die als pradisponierend für eine Luxation ermittelt wurden. Auf die Bedeutung der Erhaltung der effektiven Schenkelhalslänge bei der Implantation einer Totalprothese wird besonders hingewiesen.

     

Dislocation following total hip arthroplasty

The rate of postoperative dislocation after Stanmore total hip arthroplasty in 427 cases was 4.9%; 1.4% were classified as recurrent cases. Retroversion of the acetabular component and postoperative joint laxity were the only factors that were found to predispose to dislocation. The importance of preserving the effective femoral neck length during total hip arthroplasty is emphasized.     

Cementless total hip arthroplasty and limb-length equalization in patients with unilateral Crowe type-IV hip dislocation

BACKGROUND: Total hip arthroplasty in patients with unilateral congenital high dislocation of the hip (Crowe type IV) presents many challenges, including the problem of a marked limb-length discrepancy. The purpose of this retrospective study was to analyze the results of total hip replacement with limb-length equalization in these patients. METHODS: From 1988 to 1996, fifty-six patients (forty-seven women and nine men) with unilateral Crowe type-IV dislocation of the hip were treated with a cementless total hip arthroplasty at a mean age of 35.4 years. The preoperative limb-length discrepancy averaged 4.9 cm. Prior to the total hip arthroplasty, forty-eight patients with a limb-length discrepancy of >4.0 cm underwent iliofemoral distraction with use of an external fixator for eight to seventeen days. The acetabular cup was placed in the anatomical position in every patient. Shortening femoral osteotomies were not required. RESULTS: The iliac fixator pins loosened in six patients. No patient had a pin-site infection, hip joint infection, or nerve palsy. At the time of follow-up, at an average of 147.2 months, the Harris hip score averaged 90.2 points. Overall, the mean lengthening after the total hip arthroplasty was 4.6 cm. There were no revisions of the femoral stem. Nine cups were revised, four because of polyethylene wear and five because of loosening. CONCLUSIONS: We were able to safely place the acetabular cup at the anatomical position without femoral shortening by bringing the femoral head to the normal level preoperatively; thus, we could restore nearly normal limb length. We believe that our twelve-year results are similar to those of total hip arthroplasty in patients without dysplasia.     

Surgical approaches to total hip arthroplasty

Surgical exposure of the hip for trauma, infection, or reconstruction can be adequately accomplished through a variety of surgical approaches. This article describes in detail five classic approaches to the hip: Smith-Petersen (anterior), Watson-Jones (anterolateral), Hardinge (direct lateral), transtrochanteric, and posterolateral. In addition, recently described mini-incision posterior and anterior approaches are outlined.     

髋关节置换术后下肢不等长原因分析及预防

目的探讨人工髋关节置换（THA）术后引起双下肢不等长的原因及相应的防治对策。方法对126例单侧髋关节疾病患者采用THA治疗。通过术前双侧髂前上棘至髌骨上缘反复测量验证、骨盆标准X线正位片及股骨头模板运用确定术中股骨颈截骨平面及股骨距保留长度,术中综合考虑麻醉、偏心距、假体设计及股骨头颈长等影响因素。结果患髋的Harris评分从术前（50±5.6）分（P〈0.01）改善为（88±3.8）分（P〈0.01）。术后双下肢等长或长度差异在5mm以内者102例（80.9%）。结论通过术前骨盆正位X线片上测量评估,术中综合考虑骨、软组织、假体等相关因素,可有效预防THA术后引起的双下肢不等长。