Anatomic hip range of motion after implantation during total hip arthroplasty as measured by a navigation system

Simulation of prosthetic impingement is important for preventing complications after total hip arthroplasty (THA). Although the anatomical hip range of motion (ROM) in patients after THA is an essential parameter for these simulations, previous simulation studies substituted various clinical hip ROMs for the anatomical hip ROM. Using a navigation system, anatomical hip ROM was accurately assessed after implantation during primary THA in 30 patients. We found that the hip could be passively moved to 113 degrees of flexion, 34 degrees of extension, 46 degrees of abduction, 75 degrees of internal rotation, and 36 degrees of external rotation. Almost all reference hip ROMs used in previous simulations were smaller than these values. Therefore, wider hip ROM values should be used as parameters for such simulations.     

The continuum of hip range of motion: From soft-tissue restriction to bony impingement

Traditional studies of hip kinematics have not identified which anatomic structures limit the range of motion (ROM) when the hip is placed in different maneuvers. In this study, we attempted to answer two questions: (a) During which maneuvers is the motion of the hip limited by bony impingement between the femur and pelvis? (b) When is hip ROM determined by the constraint of soft tissues and to what extent? ROM of eight cadaveric hips was measured in 17 maneuvers using a motion capture system. The maneuvers were recreated in silico using 3D CT models of each specimen to detect the occurrence of bony impingement. If bony impingement was not detected, the variable component of 3D hip motion was increased until a collision was detected. The difference between the virtual ROM at the point of bony impingement and the initial ROM measured experimentally was termed as the soft-tissue restriction. The results showed that bony impingement was present in normal hips during maneuvers consisting of high abduction with flexion, and high flexion combined with adduction and internal rotation. At impingement-free maneuvers, the degree of soft tissue restriction varies remarkably, ranging from 4.9° ± 3.8° (internal rotation) at 90° of flexion to 80.0° ± 12.5° (internal rotation) at maximum extension. The findings shed light on the relative contributions of osseous and soft tissues to the motion of the hip in different maneuvers and allow for a better understanding of physical exams of different purposes in diagnosing bone- or soft tissue-related diseases.     

Dynamic measurements of hip movement in deep bending activities after total hip arthroplasty using a 4-dimensional motion analysis system

Although deep hip bending activities are often required in Asian populations because of traditional lifestyles and religious practices, few have examined the required hip range of motion (ROM) in these activities after total hip arthroplasty (THA). We performed postoperative motion analysis to evaluate the differences in required ROMs between Japanese-style and Western-style deep hip bending activities, to investigate whether prosthetic impingement would occur during these activities and to clarify the necessity for precautions in these activities after THA. Japanese-style activities did not require larger hip ROMs than Western-style ones, and all required hip flexion angles were less than 120°. Prosthetic impingement was not observed, with a safety margin 10° or higher until impingement in any directions of flexion, adduction, or internal rotation for any activities. Thus, particular postoperative precautions for Japanese-style activities are not required.     

Compliant positioning of total hip components for optimal range of motion.

Impingement between femoral neck and endoprosthetic cup is one of the causes for dislocation in total hip arthroplasty (THA). Choosing a correct combined orientation of both components, the acetabular cup and femoral stem, in manual or computer-assisted implantation will yield a maximized, stable range of motion (ROM) and will reduce the risk for dislocation. A mathematical model of a THA was developed to determine the optimal combination of cup inclination, cup anteversion, and stem antetorsion for maximizing ROM and minimizing the risk for cup-neck impingement. Single and combined hip joint motions were tested. A radiographic definition was used for component orientation. Additional parameters, such as stem-neck (CCD) angle, head-neck ratio, and the design of the acetabular opening, were also considered. The model showed that a maximized and safe ROM requires compliant, well-defined combinations of cup inclination, cup anteversion, and stem antetorsion depending on the intended ROM. Radiographic cup anteversion and stem antetorsion were linearly correlated. Additional internal rotation reduced flexion, and additional external rotation reduced extension, abduction and adduction. The articulating hemispheric surface of acetabular cups should be oriented between 40 degrees and 45 degrees of radiographic inclination, between 20 degrees and 28 degrees of radiographic cup anteversion, and should be combined with stem antetorsion so that the sum of cup anteversion plus 0.7 times the stem antetorsion equals 37 degrees. Final component orientation must also consider cup containment, implant impingement with bone and soft tissue, and preoperative skeletal contractures or deformities to achieve the optimal compromise for each patient.     

Association between femoroacetabular impingement syndrome and limited lateral hip rotation in young athletes: A case–control study

Purpose:Hip pain is very common in athletes. One of the main disorders causing hip pain is femoroacetabular impingement syndrome. This study aimed to identify a new etiological risk factor for femoroacetabular impingement in the hip.Methods:This case–control study included 88 young athletes, 34 with pains in the hip (supposedly with femoroacetabular impingement) and 54 controls. Femoroacetabular impingement was diagnosed with a flexion, adduction, internal, and rotation test and a particular type of hip pain during sports activities. The medial (internal) and lateral (external) hip ranges of rotation have been measured with an inclinometer. The data were analyzed using a t-test, the Wilcoxon test, the Mann–Whitney U test, and logistic regression.Results:There is a statistically significant difference in the external hip rotation range between the athletes with hip pain and controls. Logistic regression analysis showed that external hip range of motion is significantly associated with femoroacetabular impingement.Conclusion:Limited external hip range of motion was found to be significantly associated with the diagnosis of femoroacetabular impingement in young athletes. A biomechanical explanation of the hypothesis that limited external hip rotation can predict femoroacetabular impingement is given. Based on our results, the hip’s lateral range of motion screening can be advised within the regular screening of young athletes. Kinesiotherapeutic procedures for stretching the muscles of the medial hip rotors can be advised to prevent the lateral hip rotation restriction and lower the risk of femoroacetabular impingement in case the limited rotation is due to muscular restriction.Level of evidence:level III—case–control study.     

Metal-on-metal hip resurfacing: the effect of cup position and component size on range of motion to impingement

The aim of this dry bone study was to determine the range of hip motion to impingement for different hip resurfacing cup positions and component sizes. The maximum angles of hip flexion, extension, abduction, and adduction were calculated from 3-dimensional coordinates for: 1. Cup inclination of 30 degrees , 40 degrees , 50 degrees , 60 degrees , and 70 degrees with fixed anteversion; 2. Cup anteversion of 0 degrees , 10 degrees , 25 degrees , 35 degrees , and 45 degrees with fixed inclination; and 3. 3 different component sizes on the same size dry bones. An acetabular component inclination of 50 degrees and an anteversion of 25 degrees allowed the most physiologic range of hip motion. A larger-diameter femoral component relative to the native femoral neck diameter resulted in a greater range of hip motion to impingement.     

Metal neck and liner impingement in ceramic bearing total hip arthroplasty

Although impingement between the neck of the metallic stem and the ceramic liner has been suspected to be the cause of ceramic liner failure in ceramic‐on‐ceramic total hip arthroplasty (THA), no report has directly demonstrated microscopic damage on ceramic liner. We performed 18 reoperations on 18 patients who had undergone third generation ceramic‐on‐ceramic THA. Considering impingement, 16 patients, who were reoperated more than 1 year after previous ceramic bearing THA, were evaluated. Retrieved alumina liners, showing evidence of impingement, were examined by means of visual inspection and scanning electron microscopy (SEM). Four of the 16 hips showed neck notching and black stained liners, evidence of metallic neck to ceramic impingement. Impinged alumina bearings had been implanted for an average of 62.5 months (range: 35–99 months) before reoperation. SEM of the black stained area demonstrated disruptive wear and loss of surface integrity. Furthermore, one liner had multiple microcracks, and its cross‐sectional SEM analysis revealed one microcrack propagating into the deep portion of the ceramic liner. Our observations suggest that metal neck‐to‐ceramic impingement in ceramic‐on‐ceramic THA can cause microcrack formation in ceramic liner. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:218–222, 2011     

Failure of larger-diameter metal-on-metal total hip arthroplasty resulting from anterior iliopsoas impingement

Anterior iliopsoas impingement is a recognized cause of persistent groin pain after total hip arthroplasty. We report 3 patients with failed total hip arthroplasties resulting from anterior iliopsoas and capsular impingement secondary to a metal femoral ball with a diameter larger than the native femoral head. All patients had the same implant design. Resolution of symptoms occurred in all patients after revision surgery. To our knowledge, this is the first report of this potential failure mechanism with these large-diameter implant designs and should be considered in the appropriate clinical scenario.     

不同股骨头颈直径比与髋臼角对人工髋关节活动的影响

目的：探讨不同股骨头颈直径比和髋臼安置方位对人工全髋关节活动范围的影响。方法：应用计算机模拟技术建立人工全髋关节三维计算机模型，模拟测试三种不同头颈直径比全髋假体在体外不同安置方位的活动范围。结果：全髋关节置换术后的活动范围不仅取决于假体设计的某些参数，如头颈直径比，还取决于假体安置的某些参数，如臼杯的外展角和前倾角，假体柄的前倾角，以及臼杯和柄的相互方向等等。人工全髋关节在合适的安置方位内产生最佳的活动范围。头颈比越大，同一安置方位同一方向的活动范围越大。结论：人工全髋关节相对较大的头颈直径比在合适的安置方位内产生最佳的活动范围，可减少全髋关节置换术(THA)后假体撞击机会。国产镁硅玉全髋假体由于头颈比太小，在任何安置方位内其活动范围都较小，将难于满足日常生活需要。     

An in vivo model for intraoperative assessment of impingement and dislocation in total hip arthroplasty

We have developed an intraoperative model to quantify total hip arthroplasty impingement and dislocation mechanics using fluoroscopy and shape-matching techniques. Two patient groups were investigated: group 1 consisted of 12 hips using 28- or 32-mm femoral heads and an anterolateral surgical approach, and group 2 consisted of 17 hips using 22- or 26-mm femoral heads and a posterolateral surgical approach. During intraoperative hip stability testing consisting of extension and external rotation motions, group 1 was more unstable, and prosthetic impingement was the major reason for dislocation. With flexion and internal rotation motions, group 2 was more unstable, and superior-lateral impingement or soft tissue traction was the major reason for dislocation. Intraoperative quantitative assessment of hip mechanics provides a safe and clinically relevant method to characterize potential complications and evolve techniques to prevent them.     

基于惯性测量单元的全髋关节置换术中髋关节活动度智能测量系统的体外验证

目的开展一项体外验证研究,评估基于惯性测量单元的智能测量系统(IMUHST)在全髋关节置换术中测量髋关节活动度的准确性。方法IMUHST系统由股骨头测量元件及电脑终端组成。采用不透X线的人工骨右侧髋臼磨锉后置入直径60 mm的臼杯,股骨髓腔内置入股骨柄,模拟全髋关节置换术,将IMUHST系统直径36 mm的试模股骨头装配于股骨侧股骨柄上。将CT图像数据测量的髋关节活动度作为参照标准,分析IMUHST系统测量结果(观察组)与参照标准(对照组)之间的差异,并计算组内相关系数(ICC)值。结果观察组与对照组在髋关节屈伸、内收外展、内旋外旋轴线上测量的活动度差异无统计学意义(P>0.05),ICC值均为0.982。结论体外研究证实IMUHST系统测量全髋关节置换术中髋关节活动度具有较高的准确性,该智能辅助系统具有广阔的临床应用前景。     

Variability in hip range of motion on clinical examination

The goal of this study was to determine the interobserver and intraobserver reliability of physical examination in determining hip range of motion. Twenty normal hips, 21 hips with osteoarthritis, and 21 hips of patients more than 12 months after a total hip arthroplasty were examined for visual passive range of motion. These 62 hips were examined by 2 experienced surgeons and by 3 trainees. The 2 experienced examiners repeated their clinical examinations in 19 patients to determine the intraobserver reliability. Intraclass correlation coefficients (ICCs) indicated moderate interobserver agreement in estimates of clinical hip motion (ICC for hip flexion, 0.56 +/- 0.12; for hip abduction, 0.48 +/- 0.13). Intraclass correlation coefficients also suggest only moderate intraobserver reliability in measurements of hip motion (ICC for hip flexion, 0.62 +/- 0.14; hip abduction, 0.44 +/- 0.20). More reliable and accurate methods are needed to measure clinical hip motion before and after total hip arthroplasty.     

CT image evaluation of the internal rotation limit prior to bony impingement after total hip arthroplasty

 This study evaluated the internal rotation limit prior to bony impingement of the proximal femur on the pelvis after total hip arthroplasty (THA). Reconstructed computed tomography (CT) images of 90° hip flexion were used to simulate the internal rotation limit against safety limits measured intraoperatively. Ninety joints in 86 subjects (12 men and 74 women) underwent THA for the treatment of secondary coxarthrosis. The correlation between the internal rotation limit prior to the bony impingement intraoperatively and the simulated internal rotation angle on the reconstructed CT image was statistically significant. We provide a new method to simulate the internal rotation limit prior to bony impingement based on postoperative CT. Received: October 8, 2001 / Accepted: March 19, 2002     

Effects of the femoral offset and the head size on the safe range of motion in total hip arthroplasty

The purpose of this study was to quantify the effects of femoral offset and head size on range of motion (ROM) after total hip arthroplasty. Modular prostheses were implanted into 11 cadaveric hips using a posterolateral approach and tested for ROM with 3 different offsets and 5 different femoral head sizes. Increasing the femoral offset to 4 and 8 mm resulted in 21.1 degrees and 26.7 degrees of improved flexion, and 13.7 degrees and 21.2 degrees of improved internal rotation, respectively. The ROM improved in a head size-dependent manner primarily because of increasing the jumping distance of the femoral head rather than delaying any impingement. In contrast, the effectiveness of femoral offset was driven by delayed osseous impingement.     

A novel system of four-dimensional motion analysis after total hip arthroplasty.

We have developed a novel system of four-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities. This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system's measurements, open MRI was used to evaluate positions of skin markers against bones in five healthy volunteers in various postures. No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture. The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.     

Factors affecting range of motion in total knee arthroplasty using high flexion prosthesis: A prospective study

Background:

High flexion implants have been reported to provide better range of motion (ROM). The few studies analyzing the factors affecting the ROM are scarce. This study aims to find the factors that affect ROM when using a high flex knee design (INDUS knee).

Materials and Methods:

Two hundred and fifty three consecutive patients of total knee arthroplasty (TKA) done by using INDUS knee prosthesis between Sept 2008 and Sept 2009 were included in the study. The cases with osteoarthritis (OA) and Rheumatoid arthritis (RA) were included in study. 5 patients were lost to followup and 248 patients (267 knees, 19 bilateral, 221 OA, and 46 RA) were analyzed for the following factors – sex, age, body mass index (BMI), preoperative ROM, flexion deformity, preoperative total knee score and functional score, time of tourniquet release and patella resurfacing. Subgroup classification using above factors was performed and statistical analysis of effect of all the above factors on final knee ROM was done. Assessment was done preoperatively and at 3 months, 6 months and 1 year postoperatively. The final outcome evaluation was done at one year followup.

Results:

The mean age was 68.2 years (range 40-89 years) with 79 males and 189 females. The mean knee range improved from 97.62 ± 11° to 132 ± 8°. Factors that positively affect ROM of INDUS knee prosthesis at the end of 1 year were preoperative ROM, total knee score and functional score, and diagnosis of osteoarthritis, whereas BMI, preoperative flexion deformity has a negative influence on final flexion at the end of 1 year. Age and gender of the patients, patella resurfacing, and use of two different tourniquet protocols did not affect the final outcome.

Conclusion:

Preoperative ROM and preoperative functional status are the most important factors affecting final range. Patients should be counseled accordingly and made to understand these factors.     

Factors Affecting Bony Impingement in Hip Arthroplasty

Computer modeling of 10 patients' computed tomographic scans was used to study the variables affecting hip arthroplasty range of motion before bony impingement (ROMBI) including acetabular offset and height, femoral offset, height and anteversion, and osteophyte removal. The ROMBI was compared with the ROM before component impingement and the native hip ROM. The ROMBI decreased with decreased total offset and limb shortening. Acetabular offset and height had a greater effect on ROMBI than femoral offset and height. The ROMBI lost with decreased acetabular offset was not fully recoverable with an increase in femoral offset or osteophyte removal. Bony impingement increased and component impingement decreased with decreased acetabular offset and increased head diameter.     

Dislocation after total hip arthroplasty using Hueter anterior approach

A prospective study including 1764 hips has been carried out to evaluate the frequency of dislocation while using the Hueter anterior approach and the correlated factors. The dislocation group was compared with the patients without dislocation. We observed 27 dislocations (1.5%). The dislocation rate when using 28 mm head diameter was 0.5%. Two patients underwent a revision for recurrent dislocations. Correlated factors for dislocation were male sex, high body mass index, etiology of osteonecrosis, low head diameter, high bleeding, and low postoperative ROM. Dislocation risk while using Hueter approach is one of the lowest in the literature. The main disadvantages are the necessity for a specific orthopedic table and a more difficult exposure of the femur.