Studies in Osteoarthritis of the Hip: Part IV, * Biomechanics and clinical considerations

Present knowledge of hip biomechanics supports the contention that the stresses imposed on the hip on the side of the longer leg are greater than normal; those on the short side are comparably reduced. Indirect measurements by various authors have demonstrated greater stress on the hip if the pelvis is adducted, a persistent and chronic condition of the hip joint on the side of a long leg. Furthermore the pressure on the acetabulum will be displaced laterally in these circumstances. The consistent pattern of degeneration in unilateral superolateral O A hip is what would be expected if the consequences of leg-length disparity were as described. Leg-length inequality may be a major contributing factor in the development of unilateral degenerative disease of the hip of this type.A clinical method of estimating leg-length disparity is described. Clinical findings in patients support the hypothesis that hip stress is increased on the side of a longer leg.     

Normal hip joint contact pressure distribution in single-leg standing--effect of gender and anatomic parameters.

A practical and easy-to-use analysis technique that can study the patient's hip joint contact force/pressure distribution would be useful to assess the effect of abnormal biomechanical conditions and anatomical deformities on joint contact stress for treatment planning purpose. This technique can also help to establish the normative database on hip joint contact pressure distribution in men and women in different age groups. Twelve anatomic parameters and seven biomechanical parameters of the hip joint in a normal population (41 females, 15 males) were calculated. The inter-parameter correlations were investigated. The pressure distribution in the hip joint was calculated using a three-dimensional discrete element analysis (DEA) technique. The 3D contact geometry of the hip joint was estimated from a 2D radiograph by assuming that the femoral head and the acetabular surface were spherical in shape. The head-trochanter ratio (HT), femoral head radius, pelvic height, the joint contact area, the normalized peak contact pressure, abductor force, and the joint contact force were significantly different between men and women. The normalized peak contact pressure was correlated both with acetabular coverage and head-trochanter ratio. Change of abductor force direction within normal variation did not affect the joint peak contact pressure. However, in simulated dysplastic conditions when the CE angle is small or negative, abductor muscle direction becomes very sensitive in joint contact pressure estimation. The models and the results presented can be used as the reference base in computer simulation for preoperative planning in pelvic or femoral osteotomy.     

Studies in Osteoarthritis of the Hip: Part II, * Osteoarthritis of the hip and leg-length disparity

An x-ray method is described for the determination of leg-length inequality in the standing subject, Its precision is compared to that of other methods in current use. The geometrical considerations which are inherent in any radiographic method of leg-length determination are summarized. Sixty-seven patients with OA hip were studied; 62 were considered to be idiopathic and 36 of these idiopathic cases were superolateral in type. Measurements in these 36 patients showed significant leg-length disparity, most of the diseased hips being found on the side of the longer leg. If allowance is made for shortening due to disease, the frequency and bias of the disparity are highly significant. The strong association between OA hip of this type and a long leg suggests a causal relationship.     

A 42-year-old patient presenting with femoral head migration after hemiarthroplasty performed 22 years earlier: a case report

Introduction

Treatment of femoral neck fractures in young adults may require total hip arthroplasty or hip hemiarthroplasty using a bipolar cup. The latter can, however, result in migration of the femoral head and poor long-term results.

Case presentation

We report a case of femoral head migration after hemiarthroplasty performed for femoral neck fracture that had occurred 22 years earlier, when the patient (a Japanese man) was 20 years old. He experienced peri-prosthetic fracture of the femur, subsequent migration of the prosthesis, and a massive bone defect of the pelvic side acetabular roof. After bone union of the femoral shaft fracture, the patient was referred to our hospital for reconstruction of the acetabular roof. Intra-operatively, we placed two alloimplants of bone from around the transplanted femoral head into the weight-bearing region of the acetabular roof using an impaction bone graft method. We then implanted an acetabular roof reinforcement plate and a cemented polyethylene cup in the position of the original acetabular cup. Eighteen months post-operatively, X-rays showed union of the transplanted bone.

Conclusions

Treatment of femoral neck fractures in young adults is usually accomplished by osteosynthesis, but it may be complicated by femoral head avascular necrosis or by infection or osteomyelitis. In such cases, once an infection has subsided, either hip hemiarthroplasty using a bipolar cup or total hip arthroplasty may be required. However, if the acetabular side articular cartilage is damaged, a bipolar cup should not be used. Total hip arthroplasty should be performed to prevent migration of the implant.     

Long-term risk of receiving a total hip replacement in cancer patients

Aim: To investigate whether cancer patients have an increased risk of receiving a total hip replacement compared to the standard population of Norway. Materials and methods: By linking of The Cancer Register of Norway and The Norwegian Arthroplasty Register we obtained information on cancer diagnoses (type, date of diagnosis), total hip arthroplasties and date of death for all patients living in Norway. This includes 741,901 patients categorized into three groups: 652,197 patients with at least one cancer diagnosis but no hip arthroplasties, 72,469 patients with at least one hip arthroplasty but no cancer diagnosis and 17,235 patients who have at least one cancer diagnosis and at least one hip arthroplasty. Within this latter group, 8563 individuals had been diagnosed with cancer prior to a total hip arthroplasty. Statistical methods applied in this study were Cox interval censored regression models and standardized incidence ratios (SIR). Results: Cancer patients had a slightly increased risk of receiving a total hip arthroplasty compared to the Norwegian population (SIR = 1.15 (95% CI, 1.12–1.17)). For primary tumours located cranially to the pelvic area there was no significant increase in risk for hip arthroplasty. An exception was breast cancer (SIR = 1.13 (95% CI 1.08–1.18)). Cancer located in the pelvic region (SIR = 1.20 (95% CI 1.16–1.24)), malignant lymphoma (SIR = 1.30 (95% CI 1.15–1.46)) and leukaemia (SIR = 1.17 (95% CI 1.01–1.34)) had an increased risk for receiving a total hip arthroplasty. Conclusion: Cancer survivors, mainly those with pelvic and lympho-hematological malignancies, have a small statistically significant increase in risk for receiving total hip arthroplasty.     

Biomechanics of the hip and birth in early Homo

A complex of traits in the femur and pelvis of Homo ereclus and early “erectus-like” specimens has been described, but never satisfactorily explained. Here the functional relationships between pelvic and femoral structure in humans are explored using both theoretical biomechanical models and empirical tests within modern samples of diverse body form (Pecos Amerindians, East Africans). Results indicate that a long femoral neck increases mediolateral bending of the femoral diaphysis and decreases gluteal abductor and hip joint reaction forces. Increasing biacetabular breadth along with femoral neck length further increases M-L bending of the femoral shaft and maintains abductor and joint reaction forces at near “normal” levels. When compared to modern humans, Homo erectus and early “erectus-like” specimens are characterized by a long femoral neck and greatly increased M-L relative to A-P bending strength of the femoral shaft, coupled with no decrease in hip joint size and a probable increase in abductor force relative to body size. All of this strongly suggests that biacetabular breadth as well as femoral neck length was relatively large in early Homo. Several features preserved in early Homo partial hip bones also indicate that the true (lower) pelvis was very M-L broad, as well as A-P narrow. This is similar to the lower pelvic shape of australopithecines and suggests that nonrotational birth, in which the newborn's head is oriented transversely through the pelvic outlet, characterized early Homo as well as Australopithecus. Because M-L breadth of the pelvis is constrained by other factors, this may have limited increases in cranial capacity within Homo until rotational birth was established during the late Middle Pleistocene. During or after the transition to rotational birth biacetabular breadth decreased, reducing the body weight moment arm about the hip and allowing femoral neck length (abductor moment arm) to also decrease, both of which reduced M-L bending of the proximal femoral shaft. Variation in femoral structural properties within early Homo and other East African Early Pleistocene specimens has several taxonomic and phylogenetic implications. © 1995 Wiley-Liss, Inc.     

Recovery of walking speed and symmetrical movement of the pelvis and lower extremity joints after unilateral THA

In 17 patients with unilateral hip disease who underwent total hip arthroplasty (THA), the gait was analyzed preoperatively and 1, 3, 6, and 12 months after unilateral THA using a Vicon system to assess the recovery of walking speed and symmetrical movement of the hip, knee, ankle, and pelvis. The walking speed of these patients reached that of normal Japanese persons by 12 months after surgery. Walking speed was correlated with the range of hip motion on the operated side at 1 month postoperatively, and was correlated with the hip joint extension moment of force on both sides from 3 to 6 months after surgery. Before THA, asymmetry was observed in the range of the hip motion, maximum hip flexion, maximum hip extension, maximum knee flexion, as well as in pelvic obliquity, pelvic tilt, and pelvic rotation. There were no differences of the stride length or step length between both sides throughout the observation period. The preoperative range of hip flexion on the operated side during a gait cycle (21.3+/-7.9 degrees ) was significantly smaller than on the non-operated side (46.7+/-7.1 degrees ), and the difference between sides was still significant at 12 months after surgery (35.1+/-6.2 degrees on the operated side and 43.6+/-5.7 degrees on the non-operated side). The majority (74%) of the difference in hip motion range during this period was due to the difference in maximum extension of the hip. The increase in the range of pelvic tilt and the range of motion of the opposite hip showed an inverse correlation with the range of motion of the operated hip, suggesting a compensatory preoperative role. However, this correlation became insignificant after 6 months postoperatively. Asymmetry of the range of hip motion persisted at 12 months after THA in patients with unilateral coxoarthropathy during free level walking, while the operation normalized the spatial asymmetry of other joints and the walking speed prior to the recovery of hip motion.     

Quantitative assessment of gait determinants during single stance via a three-dimensional model--Part 2. Pathological gait

A three-dimensional model for normal gait formulated in Part 1 is now altered to simulate the dynamics of pathological walking. Mechanisms fundamental to the production of a normal gait pattern are systematically removed, in order to assess contributions from individual gait determinants. Four separate pathological cases are studied: a model neglecting ankle plantarflexor activity; absence of stance knee flexion-extension and foot and knee interaction; both pelvic list and transverse pelvic rotation removed; and finally, a model with all major gait determinants missing. These are used collectively to show that stance knee flexion-extension and foot and knee interaction successively dominate lower-extremity dynamical response during the single support phase of normal gait. The hip abductor muscles, while effecting pelvic list, serve to stabilize this limb, rather than actively determine whole-body vertical acceleration. Mechanisms compensating for a loss in joint motion are also explored. Complete ankle loss may be successfully compensated with increased hip abductor muscle activity; the loss of both ankle and knee, however, demand unacceptable levels of vertical pelvic displacement.     

Simulated hip abductor strengthening reduces peak joint contact forces in patients with total hip arthroplasty

Lower extremity muscle strength training is a focus of rehabilitation following total hip arthroplasty (THA). Strength of the hip abductor muscle group is a predictor of overall function following THA. The purpose of this study was to investigate the effects of hip abductor strengthening following rehabilitation on joint contact forces (JCFs) in the lower extremity and low back during a high demand step down task. Five THA patients performed lower extremity maximum isometric strength tests and a stair descent task. Patient-specific musculoskeletal models were created in OpenSim and maximum isometric strength parameters were scaled to reproduce measured pre-operative joint torques. A pre-operative forward dynamic simulation of each patient performing the stair descent was constructed using their corresponding patient-specific model to predict JCFs at the ankle, knee, hip, and low back. The hip abductor muscles were strengthened with clinically supported increases (0–30%) above pre-operative values in a probabilistic framework to predict the effects on peak JCFs (99% confidence bounds). Simulated hip abductor strengthening resulted in lower peak JCFs relative to pre-operative for all five patients at the hip (18.9–23.8 ± 16.5%) and knee (20.5–23.8 ± 11.2%). Four of the five patients had reductions at the ankle (7.1–8.5 ± 11.3%) and low back (3.5–7.0 ± 5.3%) with one patient demonstrating no change. The reduction in JCF at the hip joint and at joints other than the hip with hip abductor strengthening demonstrates the dynamic and mechanical interdependencies of the knee, hip and spine that can be targeted in early THA rehabilitation to improve overall patient function.     

全髋关节置换术与双极人工股骨头置换术治疗老年股骨颈骨折的临床疗效

目的：探讨全髋关节置换术（THA）与双极人工股骨头置换术（BHA）治疗老年股骨颈骨折的临床疗效。方法：选择2013 年7 月-2015 年3 月我院收治的老年股骨颈骨折患者90 例,根据手术方法不同将患者分为全髋关节置换组（THA 组）和双极人工股 骨头置换组（BHA 组）,每组45 例。观察并比较两组患者的手术时间、术中出血量、住院时间、术后并发症的发生率及手术效果。结 果：两组患者的手术时间、术中出血量及住院时间比较,差异无统计学意义（P>0.05）;THA 组并发症的发生率明显低于BHA 组, 差异具有统计学意义（P<0.05）;术后1 年,两组手术优良率比较,差异无统计学意义（P>0.05）;术后两年及三年,THA 组手术优良 率明显高于BHA 组,差异具有统计学意义（P<0.05）。结论：THA和BHA 治疗老年股骨颈骨折均具有良好的临床疗效,但THA具 有更好的远期疗效,而且术后并发症的发生率较低。     

全髋关节置换术与人工股骨头置换术治疗老年股骨颈骨折的疗效比较

目的:探讨全髋关节置换术与人工股骨头置换术治疗老年股骨颈骨折的疗效。方法:选择在我院的82例行手术置换治疗的老年股骨颈骨折患者,随机分为观察组和对照组,每组41例。观察组采用全髋关节置换术,而对照组实施人工股骨头置换术。观察并比较两组患者的手术时间、术中出血量、血压、术后引流及髋关节功能等。结果:观察组手术时间、术中出血量及收缩压均显著高于对照组,差异具有统计学意义(P<0.05);术后引流量及并发症的发生率,两组比较无显著性差异(P>0.05)。观察组患者术后Harris评分为(93.25±4.51),对照组患者Harris评分为(82.76±3.82),观察组显著优于对照组,差异具有统计学意义(P<0.05)。结论:与人工股骨头置换术相比,全髋关节置换术用于治疗老年股骨颈骨折具有创伤小,恢复快的临床效果,患者术后髋关节功能恢复情况良好,值得在临床推广应用。     

全髋关节置换术治疗晚期非创伤性股骨头缺血性坏死

目的:探讨全髋关节置换术治疗晚期非创伤性股骨头缺血性坏死的临床疗效,为临床治疗提供参考依据.方法:将我院进行全髋关节置换术治疗晚期股骨头缺血性坏死患者25例(30髋)按病因分三组,A组酒精性17例,B组为激素性6例,C组潜水性2例,记录各组患者术前、术后的临床症状,患髋功能,X片等,并进行Harris评分,对结果进行评价分析.结果:三组术后Harris评分分别为(89.7±2.8)、(81.5±3.1)分、(87.8±2.9)分,经方差分析,差异有统计学意义(P＜0.05);三组术后假肢松动髋数率分别为4.8％、16.7％、0％,经卡方检验,差异有统计学意义(P＜0.05);三组术后随访3年总体髋部优良率分别为100％、83.3％、100％,经卡方检验,差异有统计学意义(P＜0.05).结论:全髋关节置换术治疗晚期非创伤性股骨头缺血性坏死疗效较好,对酒精性病因患者疗效最好.     

Measuring improvement following total hip and knee arthroplasty using the SF-36 Health Survey

The aim of this study was to evaluate the impact of total hip or knee arthroplasty upon quality of life in elderly patients. The study was carried out at the Clinic for Orthopaedic Surgery Lovran on 74 total hip arthroplasty and 70 total knee arthroplasty patients. All patients had completed the Medical Outcomes Study 36-Item Short Form in the week having preceded their surgery and then again postoperatively, 2 years after. The data obtained were statistically processed at the level of physical function, role limitations due to physical problems, role limitations due to emotional problems, social function, mental health, energy or vitality, pain and general health perception, and change in health. The primary total hip arthroplasty patients showed significant improvement at all levels measured. Similarly, the primary total knee arthroplasty patients expressed significant improvement according to all the parameters but the mental health assessment. Comparison of outcomes between the two assessment groups of patients resulted in slightly superior quality of life outcomes in total hip arthroplasty patients. It can be concluded that total hip or knee arthroplasty significantly enhances the health related quality of life in elderly patients.     

A long-lasting bisphosphonate partially protects periprosthetic bone,but does not enhance initial stability of uncemented femoral stems: A randomized placebo-controlled trial of women undergoing total hip arthroplasty

Low bone quality may compromise the success of cementless total hip arthroplasty in high-risk patients such as elderly women. Zoledronic acid is a long-lasting antiresorptive agent, which is known to reduce short-term periprosthetic bone loss. However, its effect on femoral stem stability is not well known. Forty-nine female patients with a mean age of 68 years (range, 51–85 years) scheduled to undergo cementless total hip arthroplasty due to osteoarthritis were randomized in this double-blind, placebo-controlled trial to receive a single postoperative infusion of zoledronic acid or placebo. Patients were evaluated for up to four years postoperatively for femoral stem migration measured by radiostereometric analysis, bone mineral density (BMD) measured by dual X-ray absorptiometry, functional recovery, and patient-reported outcome scores. Implant survival was determined at nine years postoperatively. Zoledronic acid did not reduce the femoral stem migration that occurred predominantly during the settling period of the first 3–6 months. Subsequently, all femoral stems were radiographically osseointegrated. Zoledronic acid maintained periprosthetic BMD, while the expected loss of periprosthetic bone during the first 12 months was found in controls. Thereafter, periprosthetic BMD of Gruen zone 7 decreased even in the zoledronic acid group but remained 14.6% higher than that in the placebo group at four years postoperatively. Functional recovery was comparable across the groups. At nine years postoperatively, no revision arthroplasty had been performed. In conclusion, in women at high-risk for low BMD, zoledronic acid had a long-lasting, partially protective effect on periprosthetic bone loss, but the treatment did not enhance the initial femoral stem stability.     

流程管理对高龄全髋关节置换术患者的临床效果分析

目的：随着我国人口老龄化日渐严重,高龄人群中髋关节骨折或坏死的发病率明显呈上升趋势。目前,临床用于治疗该类疾病的方法主要是全髋关节置换术（THA）。但高龄患者身体机能出现衰退,术后极易出现并发症。因此,高龄患者行全髋关节置换术的围术期护理工作起着重要的作用。本文针对行全髋关节置换术的高龄患者,探讨流程管理模式的临床效果,为护理工作提供参考。方法：选择我科2010年12月至2013年6月行全髋关节置换术的12位高龄患者,随机分为对照组和观察组,分别采用常规模式和流程管理模式进行护理。对比两组患者的临床效果及对护理服务的满意度。结果：观察组患者无一例并发症出现,髋关节功能恢复良好,均痊愈出院,且住院时间比对照组短（P〈0．05）;观察组对护理服务的满意度高于对照组,差异具有统计学意义（P〈0．05）。结论：采取流程管理模式对高龄患者的围术期护理具有显著的效果,有助于减少术后并发症,提高患者对护理服务的满意度,值得临床推广。     

Progression of idiopathic thoracic or thoracolumbar scoliosis and pelvic obliquity in adolescent patients with and without limb length discrepancy

Βackground

Both limb length inequality and scoliosis are associated with pelvic obliquity.

Methods

This is an observational study of adolescents with growth potential presenting for evaluation of thoracic or thoracolumbar idiopathic scoliosis at an outpatient pediatric orthopedic clinic. Patients were evaluated for limb length discrepancy (LLD) (using bilateral femoral head height difference), pelvic obliquity (using bilateral iliac crest height difference and sacral takeoff angle), and scoliotic curve (using Cobb angle and rotation) on full spine standing radiographs. The same radiographic parameters were measured at a follow-up visit at least 2 years later.

Results

Seventy-three consecutive patients with a mean (SD) age of 13.3 (0.2) years at initial examination were included in the study. Scoliosis (major curve Cobb angle ≥?10°) was confirmed in all 73 patients, pelvic obliquity (iliac crest height difference >?1 cm or sacral takeoff angle >?5°) appeared in 23 (31.5%) patients with scoliosis, and LLD (>?1 cm femoral head height difference) was identified in 6 (8.2%) patients with scoliosis and pelvic obliquity. At a subsequent visit, a mean of 2.8 (range 2–5.8) years later, no significant change (p?>?0.05) in limb length inequality was observed but a statistically significant increase (p?<?0.05) in scoliotic and pelvic deformity parameters was found.

Conclusions

In adolescent patient population with thoracic or thoracolumbar scoliosis, the anisomelia remains stable with growth but both the scoliotic deformity and pelvic obliquity progress.

Trial registration

MGH no 2012-P-000774/1

     

流程管理对高龄全髋关节置换术患者的临床效果分析流程管理对高龄全髋关节置换术患者的临床效果分析

摘要目的：随着我国人口老龄化日渐严重,高龄人群中髋关节骨折或坏死的发病率明显呈上升趋势。目前,临床用于治疗该类疾 病的方法主要是全髋关节置换术(THA)。但高龄患者身体机能出现衰退,术后极易出现并发症。因此,高龄患者行全髋关节置换术 的围术期护理工作起着重要的作用。本文针对行全髋关节置换术的高龄患者,探讨流程管理模式的临床效果,为护理工作提供参 考。方法：选择我科2010 年12 月至2013 年6 月行全髋关节置换术的12 位高龄患者,随机分为对照组和观察组,分别采用常规 模式和流程管理模式进行护理。对比两组患者的临床效果及对护理服务的满意度。结果：观察组患者无一例并发症出现,髋关节 功能恢复良好,均痊愈出院,且住院时间比对照组短(P<0.05);观察组对护理服务的满意度高于对照组,差异具有统计学意义(P<0. 05)。结论：采取流程管理模式对高龄患者的围术期护理具有显著的效果,有助于减少术后并发症,提高患者对护理服务的满意度, 值得临床推广。     

全髋和半髋置换治疗老年股骨颈骨折的临床对比分析

目的:探讨全髋和半髋关节置换术治疗老年股骨颈骨折的临床疗效。方法:选择本院收治的70例老年股骨颈骨折患者,采用随机数字表法将其分为观察组和对照组各35例,观察组给予全髋关节置换术,对照组予以半髋关节置换术,对比两组所用手术时间、术中出血量、术后Harris评分及髋关节功能、术后并发症、疼痛率及翻修率。结果:观察组手术时间为(113.6±19.3)min,术中出血量为(432.1±32.7)ml,均显著高于对照组的(73.1±10.2)min、(201.3±30.1)m L,两组比较差异均有统计学意义(均P0.05);观察组髋关节功能总优良率、Harris评分分别为91.43%,(91.13±5.09)分,显著优于对照组的77.14%、(80.15±4.71)分,两组比较差异均有统计学意义(均P0.05);观察组不良反应发生率及翻修率分别为20.00%、0.00%,低于对照组的22.85%、5.71%,但差异均无统计学意义(均P0.05);观察组疼痛率为5.71%,显著低于对照组的25.71%,两组比较差异有统计学意义(P0.05)。结论:两种术式对股骨颈骨折的老年患者均能起到有效的治疗,均有各自的优缺点,对疼痛较为敏感和活动较多的老年患者而言,宜采用全髋关节置换术。     

Subject-specific musculoskeletal modelling in patients before and after total hip arthroplasty*

The goal of this study was to define the effect on hip contact forces of including subject-specific moment generating capacity in the musculoskeletal model by scaling isometric muscle strength and by including geometrical information in control subjects, hip osteoarthritis and total hip arthroplasty patients. Scaling based on dynamometer measurements decreased the strength of all flexor and abductor muscles. This resulted in a model that lacked the capacity to generate joint moments required during functional activities. Scaling muscle forces based on functional activities and inclusion of MRI-based geometrical detail did not compromise the model strength and resulted in hip contact forces comparable to previously reported measured contact forces.     

Pelvic instability and trunk and hip muscle recruitment patterns in patients with total hip arthroplasty

Hip and lumbar spine disorders often coexist in patients with total hip arthroplasty (THA). The current study aimed to reveal pelvic motion pathology and altered trunk and hip muscle recruitment patterns relating to pelvic motion in patients with THA. Twenty-one women who underwent THA and 12 age-matched healthy women were recruited. Pelvic kinematics and muscle recruitment patterns (i.e., amplitude, activity balance, and onset timing) of the gluteus maximus, semitendinosus, multifidus, and erector spinae were collected during prone hip extension. Compared with healthy subjects, the patients showed increased pelvic motion, especially ventral rotation, decreased multifidus muscle activity relative to the hip extensors, and delayed onset of multifidus activity, despite reaction times and speeds of leg motion not being significantly different between the groups. Furthermore, while contributing factors associated with ventral pelvic rotation were not found, delayed onset of multifidus activity was detected as a factor related to the increased anterior tilt of the pelvis (r = 0.47, p < 0.05) in patients with THA. These results suggest that patients with THA have dysfunction of the stabilizer muscles of the lumbopelvic region along with increased pelvic motion.