Range of motion studies for total hip replacements. A comparative study with a new experimental apparatus.

Significant differences in ROM exist between different THR prosthesis designs: several of the prosthesis designs tested are marginal in flexion; several millimeters of socket wear will decrease the ROM. The results also emphasize the importance of proper component orientation at surgery. The surgeon has less latitude in orienting the components of a THR with limited ROM. Subluxation and dislocation due to rim contact can be minimized with most prosthetic units by instructing the patients to abduct and/or externally rotate their hips during acute flexion. Analyses suggest that impingement of prosthesis neck and socket rim may lead to increased risk of dislocation and increased rim wear. Prostheses with adequate ROM for everyday activities should provide stability, less frequent neck and socket contact with decreased rim wear, less force transmission to acrylic-bone interface, and less diminution of ROM with wear of the socket wall.     

全髋置换后修补闭孔外肌对髋关节稳定性的影响

目的 研究闭孔外肌及其覆盖区髋关节囊的解剖特点,探讨髋关节屈曲内旋下闭孔外肌对髋关节的稳定作用.方法 取10具20侧甲醛液固定的成人尸体髋标本,左侧10髋解剖出闭孔外肌,屈曲内旋时触摸体会股骨头对闭孔外肌的膨顶;裸露闭孔外肌区的髋关节,分别测量髋关节屈曲30°、60°、90°和各屈曲角度加内旋15°时股骨头软骨面超出髋臼唇的距离;右侧10髋解剖出髋关节囊,测量后方关节囊各部厚度,观察坐股韧带走行.结果 闭孔外肌是紧贴髋关节囊后下部的唯一肌肉,在髋屈曲内旋时股骨头膨顶闭孔外肌;随着屈曲角度的增大,膨顶程度(后脱位倾向)也加大,同一屈曲角度下内旋比不内旋膨顶程度大.髋后方关节囊的厚度具有不均一性,较薄弱的两部处在闭孔外肌区,坐股韧带主干未经过闭孔外肌区,闭孔外肌区是髋后方关节囊的相对薄弱区.结论 闭孔外肌是髋关节囊后下部唯一的动力抵挡,易诱发后脱位的髋屈曲内旋体位下,抵挡股骨头脱位的主要有闭孔外肌和此肌覆盖区的关节囊,但此区关节囊相对薄弱,因此在全髋置换后应对闭孔外肌进行修补.     

Knee motion in total knee arthroplasty. A roentgen stereophotogrammetric analysis of the kinematics of the Tricon-M knee prosthesis

The three-dimensional kinematics of the Tricon-M knee prosthesis during active knee flexion and extension were recorded in 11 patients with arthrosis or rheumatoid arthritis using roentgen stereophotogrammetric analysis. Twenty-three normal knees constituted the control group. The prosthetic knees displayed the same degrees of freedom regarding rotational and translational movements as the normal knees, although the kinematics were different. A combination of internal rotation, abduction, and lateral translation of the tibia was recorded during flexion, and the reversed movements were recorded during extension. During the first 25 degrees of flexion, these movements were small, reflecting the high congruency between the articular surfaces, while beyond 25 degrees they increased. The normal knees displayed a combination of internal rotation, adduction, and medial translation of the tibia during flexion and the reversed movements during extension. The prosthetic knees also exhibited an increased posterior displacement during increasing flexion when compared with the normal knees. There was a correlation between the positioning of the femoral component in the sagittal plane and the recorded anterior/posterior translations. In conclusion, the kinematics of the Tricon-M knee prosthesis significantly differ from the normal knee, probably because of the design of the prosthesis and the absence of the cruciate ligaments.     

Femoral vein occlusion during hip arthroplasty

The mechanism of femoral vein occlusion when the hip joint is dislocated and manipulated during arthroplasty has been studied in fresh anatomic specimens. Flow studies show that moderate degrees of flexion and adduction in association with dislocation obstruct venous flow just distal to the femoral sheath at normal pressures and flow rates. Internal femoral rotation during a posterior approach to the hip causes "scissoring" of the femoral vein between femur and pubic bone. External femoral rotation during an anterior approach does not occlude flow. Injection of Batson's acrylic and neoprene latex showed that obstruction is also due to about 4 cm of shortening caused by proximal migration of the femur after dislocation in association with adduction and flexion. The femoral vein in the unsupported segment distal to the femoral sheath subsequently buckles and kinks. During operative manipulation, intermittent obstruction at this level is therefore likely to cause intermittent venous distension distally. This mechanism depletes the femoral vein of fibrinolytic activity distal to the occlusion and may explain the incidence of deep femoral thrombosis peculiar to this procedure.     

The effect of the orientation of the acetabular and femoral components on the range of motion of the hip at different head-neck ratios

BACKGROUND: Prosthetic impingement due to poor positioning can limit the range of motion of the hip after total hip arthroplasty. In this study, a computer model was used to determine the effects of the positions of the acetabular and femoral components and of varying head-neck ratios on impingement and range of motion. METHODS: A three-dimensional generic hip prosthesis with a hemispherical cup, a neck diameter of 12.25 millimeters, and a head size ranging from twenty-two to thirty-two millimeters was simulated on a computer. The maximum range of motion of the hip was measured, before the neck impinged on the liner of the cup, for acetabular abduction angles ranging from 35 to 55 degrees and acetabular and femoral anteversion ranging from 0 to 30 degrees. Stability of the hip was estimated as the maximum possible flexion coupled with 10 degrees of adduction and 10 degrees of internal rotation and also as the maximum possible extension coupled with 10 degrees of external rotation. The effects of prosthetic orientation on activities of daily living were analyzed as well. RESULTS: Acetabular abduction angles of less than 45 degrees decreased flexion and abduction of the hip, whereas higher angles decreased adduction and rotation. Femoral and acetabular anteversion increased flexion but decreased extension. Acetabular abduction angles of between 45 and 55 degrees permitted a better overall range of motion and stability when combined with appropriate acetabular and femoral anteversion. Lower head-neck ratios decreased the range of motion that was possible without prosthetic impingement. The addition of a modular sleeve that increased the diameter of the femoral neck by two millimeters decreased the range of motion by 1.5 to 8.5 degrees, depending on the direction of motion that was studied. CONCLUSIONS: There is a complex interplay between the angles of orientation of the femoral and acetabular components. Acetabular abduction angles between 45 and 55 degrees, when combined with appropriate acetabular and femoral anteversion, resulted in a maximum overall range of motion and stability with respect to prosthetic impingement. CLINICAL RELEVANCE: During total hip arthroplasty, acetabular abduction is often constrained by available bone coverage, while femoral anteversion may be dictated by the geometry of the femoral shaft. For each combination of acetabular abduction and femoral anteversion, there is an optimum range of acetabular anteversion that allows the potential for a maximum range of motion without prosthetic impingement after total hip arthroplasty. These data can be used intraoperatively to determine optimum position.     

Ultrasound study of the motion of the residual femur within a trans-femoral socket during daily living activities other than gait

This study analyses the residual femur motion of a single amputee within a transfemoral socket during a series of daily living activities. Two simultaneously transmitting, socket mounted transducers were connected to two ultrasound scanners. Displacement measurements of the ultrasound image of the femur were video recorded and measured on "paused" playback. Abduction/adduction and flexion/extension of the residual femur within the socket at any instant during these activities were estimated, knowing the relative positions of the two transducers and the position of the residual femur on the ultrasound image. Consistent motion patterns of the residual femur within the trans-femoral socket were noted throughout each monitored daily living activity of the single amputee studied. Convery and Murray (2000) reported that during level walking, relative to the socket, the residual femur extends 6 degrees and abducts 9 degrees by mid-stance while flexing 6 degrees and adducting 2 degrees by toe-off. Uphill/downhill, turning to the right and stepping up/down altered this reported pattern of femoral motion by approximately 1 degree. During the standing activity from a seated position the femur initially flexed 4 degrees before moving to 7 degrees extension, while simultaneously adducting 6 degrees. During the sitting activity from a standing position the femur moved from 7 degrees extension and 6 degrees adduction to 3 degrees flexion and 1 degree abduction. The activity of single prosthetic support to double support introduced only minor femoral motion whereas during the activity of prosthetic suspension the femur flexed 8 degrees while simultaneously adducting 9 degrees. Additional studies of more amputees are required to validate the motion patterns presented in this investigation.     

Gait abnormalities following slipped capital femoral epiphysis

The authors evaluated 30 subjects with treated unilateral slipped capital femoral epiphysis and a range of severity from mild to severe to characterize gait and strength abnormalities using instrumented three-dimensional gait analysis and isokinetic muscle testing. For slip angles less than 30 degrees, kinematic, kinetic, and strength variables were not significantly different from age- and weight-matched controls. For moderate to severe slips, as slip angle increased, passive hip flexion, hip abduction, and internal rotation in the flexed and extended positions decreased significantly. Persistent pelvic obliquity, medial lateral trunk sway, and trunk obliquity in stance increased, as did extension, adduction, and external rotation during gait. Gait velocity and step length decreased with increased amount of time spent in double limb stance. Hip abductor moment, hip extension moment, knee flexion moment, and ankle dorsiflexion moment were all decreased on the involved side. Hip and knee strength also decreased with increasing slip severity. All of these changes were present on the affected and to a lesser degree the unaffected side. Body center of mass translation or pelvic obliquity in mid-stance greater than one standard deviation above normal correlated well with the impression of compensated or uncompensated Trendelenburg gait.     

Primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement: A case report and surgical techniques

For the treatment of an intertrochanteric fracture combined with femoral head necrosis in middle-age patients, it has been controversial whether to perform fracture reduction and fixation first then total hip replacement, or direct total hip replacement. We present a rare case of 53-year-old male patient suffered from bilateral intertrochanteric fracture caused by a road traffic injury. The patient had a history of femoral head necrosis for eight years, and the Harris score was 30. We performed total hip replacement with prolonged biologic shank prostheses for primary repair. One year after the surgery, nearly full range of motion was achieved without instability (active flexion angle of 110°, extension angle of 20°, adduction angle of 40°, abduction angle of 40°, internal rotation angle of 25°, and external rotation angle of 40°). The Harris score was 85. For the middle-aged patient with unstable intertrochanteric fractures and osteonecrosis of the femoral head, we can choose primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement.     

The effect of femoral component head size on posterior dislocation of the artificial hip joint

BACKGROUND: Posterior dislocation continues to be a relatively common complication following total hip arthroplasty. In addition to technical and patient-associated factors, prosthetic features have also been shown to influence stability of the artificial hip joint. In this study, a dynamic model of the artificial hip joint was used to examine the influence of the size of the head of the femoral component on the range of motion prior to impingement and posterior dislocation following total hip replacement. METHODS: Six fresh cadaveric specimens were dissected, and an uncemented total hip prosthesis was implanted in each. Each specimen was mounted in a mechanical testing machine and loaded with use of a system of seven cables attached to the femur and pelvis that simulated the action of the major muscle groups crossing the hip joint. The hip was taken through a range of motion similar to that experienced when rising from a seated position. The three-dimensional position of the femur at the points of impingement and dislocation was recorded electronically. The range of joint motion was tested with prosthetic femoral heads of four different diameters (twenty-two, twenty-six, twenty-eight, and thirty-two millimeters). RESULTS: Significant associations were noted between the femoral head size and the degree of flexion at dislocation in ten (p = 0.001), twenty (p < 0.001), and thirty (p = 0.003) degrees of adduction. Increasing the femoral head size from twenty-two to twenty-eight millimeters increased the range of flexion by an average of 5.6 degrees prior to impingement and by an average of 7.6 degrees prior to posterior dislocation; however, increasing the head size from twenty-eight to thirty-two millimeters did not lead to more significant improvement in the range of joint motion. The site of impingement prior to dislocation varied with the size of the femoral head. With a twenty-two-millimeter head, impingement occurred between the neck of the femoral prosthesis and the acetabular liner, whereas with a thirty-two-millimeter head, impingement most frequently occurred between the osseous femur and the pelvis. CONCLUSIONS: With the particular prosthesis that was tested, increasing the diameter of the femoral head component increased the range of motion prior to impingement and dislocation, decreased the prevalence of prosthetic impingement, and increased the prevalence of osseous impingement. CLINICAL RELEVANCE: These results suggest that femoral heads with a twenty-eight-millimeter diameter increase the range of motion after total hip replacement. This may be beneficial when additional factors compromising joint stability are encountered.     

A forty millimetre head significantly improves range of motion compared with a twenty eight millimetre head in total hip arthroplasty using a computed tomography-based navigation system

Purpose

Larger-diameter (≥40 mm) femoral heads decrease the incidence of post-operative dislocation in total hip arthroplasty (THA). This study was conducted to discover whether larger-diameter femoral heads result in greater range of motion of the hip with the use of a computed tomography (CT)-based navigation system.

Methods

Thirty-nine primary THAs were performed via a posterolateral approach using a CT-based navigation system. The stem was inserted in the femur in line with the original femoral neck anteversion. Considering the range of motion during various daily activities which could occur without impingement, the cup anteversion was decided at 10 ° increments according to the stem anteversion. While the cup inclination was set at 40 ° in order to avoid a high inclination angle to prevent the edge roading between the HXLPE liner and ceramic head. After implantation, trial liners and femoral heads were used with either 28 or 40 mm diameter. Maximal hip flexion, extension, abduction, external rotation in extension at 0° and internal rotation angles in flexion at 90 ° were measured. The differences between the ranges of motion with the 40-mm and 28-mm heads were tested. The results were assessed with paired Student t-tests.

Results

The ranges of motion in flexion, extension, abduction and internal rotation angles improved significantly with the 40-mm heads compared with the 28-mm heads. The ranges of motion of cases where maximal flexion angle was 90° or less were excluded, improved significantly with the 40 mm heads.

Conclusions

We concluded that the larger-diameter 40-mm femoral prosthetic heads result in greater ranges of motion in flexion, extension, abduction and internal rotation.

     

Modular component exchange for treatment of recurrent dislocation of a total hip replacement in selected patients.

BACKGROUND: Exchange of modular components is a treatment option for the correction of recurrent dislocation of a total hip replacement. In this study, we reviewed our experience with this technique in order to define patient selection criteria and to report the outcome of treatment. METHODS: Of 2935 hips treated with primary porous-coated total hip arthroplasty, fourteen (in fourteen patients) that met certain preoperative and intraoperative criteria were treated with modular component exchange because of recurrent hip instability. The primary arthroplasties in these fourteen patients had been performed through a posterior approach. At the revisions, we removed any sources of osseous or soft-tissue impingement that contributed to dislocation. Acceptable stability at the completion of component exchange was defined as stability in maximum flexion, in full extension with external rotation, and in at least 45 degrees of internal rotation with the hip in 90 degrees of flexion and maximum adduction. RESULTS: One patient was lost to follow-up. At a mean of 5.8 years (range, 2.8 to 11.8 years) after the revision, ten of the remaining thirteen patients had not had a dislocation. Of the three patients in whom the hip dislocated after the modular component exchange, only one had recurrent dislocation; thus, recurrent dislocation was eliminated in twelve of thirteen patients. CONCLUSIONS: In selected cases, modular component exchange for the treatment of recurrent hip dislocation has a success rate comparable with that of more extensive operations. This method should be considered because it avoids the morbidity associated with revision of well-fixed components. However, to ensure the appropriateness of this surgical option, each patient must be thoroughly evaluated to identify all factors that contribute to instability and adequate intraoperative stability must be achieved.     

Anatomy, function, and rehabilitation of the popliteus musculotendinous complex

We present a clinical commentary of existing evidence regarding popliteus musculotendinous complex anatomy, biomechanics, muscle activation, and kinesthesia as they relate to functional knee joint rehabilitation. The popliteus appears to act as a dynamic guidance system for monitoring and controlling subtle transverse- and frontal-plane knee joint movements, controlling anterior-posterior lateral meniscus movement, unlocking and internally rotating the knee joint (tibia) during flexion initiation, assisting with 3-dimensional dynamic lower extremity postural stability during single-leg stance, preventing forward femoral dislocation on the tibia during flexed-knee stance, and providing for postural equilibrium adjustments during standing. These functions may be most important during mid-range knee flexion when capsuloligamentous struCtures are unable to function optimally. Because the popliteus musculotendinous complex has attachments that approximate the borders of both collateral ligaments, it has the potential for providing instantaneous 3-dimensional kinesthetic feedback of both medial and lateral tibiofemoral joint compartment function. Enhanced popliteus function as a kinesthetic knee joint monitor acting in synergy with dynamic hip muscular control of femoral internal rotation and adduction, and ankle subtalar muscular control of tibial abduction-external rotation or adduction-internal rotation, may help to prevent athletic knee joint injuries and facilitate recovery during rehabilitation by assisting the primary sagittal plane dynamic knee joint stabilization provided by the quadriceps femoris, hamstrings, and gastrocnemius.     

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.     

Factors affecting the impingement angle of fixed- and mobile-bearing total knee replacements: a laboratory study

Maximum flexion-or impingement angle-is defined as the angle of flexion when the posterior femoral cortex impacts the posterior edge of the tibial insert. We examined the effects of femoral component placement on the femur, the slope angle of the tibial component, the location of the femoral-tibial contact point, and the amount of internal or external rotation. Posterior and proximal femoral placement, a more posterior femoral-tibial contact point, and a more tibial slope all increased maximum flexion, whereas rotation reduced it. A mobile-bearing knee gave results similar to those of the fixed-bearing knee, but there was no loss of flexion in internal or external rotation if the mobile bearing moved with the femur. In the absence of negative factors, a flexion angle of 150 degrees can be reached before impingement.     

Hip range‐of‐motion (ROM) is less than normal after rotational acetabular osteotomy for developmental dysplasia of the hip: A simulated ROM analysis

The optimal reorientation of the acetabulum for developmental dysplasia of the hip (DDH) is unknown in terms of hip range‐of‐motion (ROM). The simulated ROMs of 52 DDHs after rotational acetabular osteotomy (RAO) with several patterns of femoral head coverage and those of 73 normal hips were analyzed using computer models reconstructed from CT images. After RAO with a lateral center edge angle (LCEA) of 30° and an anterior center edge angle (ACEA) of 55° producing coverage similar to that of normal hips, the maximal flexion and maximal internal rotation at 110° flexion with 20° adduction were significantly smaller than those of the normal group. To achieve ROMs after RAO similar to those of the normal group, an LCEA of 30° with an ACEA of 45°, an LCEA of 25° with an ACEA of 45° to 50°, and an LCEA of 20° with an ACEA of 50° could be preferred angles to target, even though they provided smaller coverage than that of normal hips. After RAO producing femoral head coverage similar to that of normal hips, the maximal flexion and the maximal internal rotation at 110° flexion with 20° adduction were significantly smaller than those of the normal group. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:217–223, 2016.     

应用缝匠肌治疗复发性髌骨脱位

为探讨复发性髌骨脱位(Recurrent dislocation of the patella, RDP)的治疗方法。1978年开始利用缝匠肌前移,增建一个动力性髌韧带和加强股内侧肌肌力,共治疗RDP15例,18膝;随访12例,13膝;随访时间2.5年～13年,平均4年3个月,髌骨无再脱位,膝关节伸屈功能正常,无继发关节退行性变,获得满意治疗效果。认为本方法优点在于设计合理、操作简单、效果确实、易于推广。     

切开复位联合Latarjet手术治疗陈旧性肩关节前脱位

目的评估切开复位联合Latarjet手术治疗陈旧性肩关节前脱位的临床疗效。 方法自2012年1月至2018年1月共14例陈旧性肩关节前脱位患者（16个肩关节）纳入本研究,其中男8例、女6例;年龄30~70岁,平均51.2岁;脱位时间为8~22周,平均10.2周。受伤原因为：摔伤10例,车祸伤4例。合并Hill-Sachs损伤12例,缺损占肱骨头的比例平均为32%。合并骨性Bankart损伤11例,缺损占肩胛盂的比例平均为13%。合并肩袖损伤9例,合并肱骨近端骨折6例,无一例合并神经血管损伤。术前检查肩关节活动度（前屈、外展、内旋、外旋）并记录视觉模拟评分法（visual analogue scale,VAS）、美国肩肘外科（American shoulder elbow surgeons’form,ASES）评分、美国加州大学肩关节系统（University of California at Los Angeles,UCLA）评分。术中均采用胸大肌三角肌间沟入路,彻底松解挛缩的关节囊和周围软组织,清除盂窝内的瘢痕组织后复位,再行Latarjet术重建肩胛盂弧度维持复位,同时依据损伤情况处理伴随的Hill-Sachs损伤、肩袖损伤和肱骨近端骨折等。 结果14例患者均获随访,随访时间10~22个月,平均18个月。随访期间肩关节均未出现再脱位。1例患者术后出现肩部麻木,考虑腋神经损伤,1个月后恢复正常。无感染、医源性骨折及其他血管神经损伤等并发症。与术前相比,末次随访时平均前屈角度由（65.9±10.4）°升至（112.1±13.3）°（P=0.000）,平均外展角度由（41.1±9.7）°升至（63.3±13.6）°（P=0.000）,平均内收位外旋角度由（10.7±4.3）°升至（22.1±5.1）°（P=0.000）,平均内收位内旋角度由（52.6±5.3）°升至（54.0±6.0）°（P=0.081）,VAS评分由（5.4±1.4）分降至（1.7±1.1）分（P=0.000）,ASES评分由（34.1±10.6）分升至（70.8±12.3）分（P=0.000）,UCLA评分由（10.1±3.2）分升至（22.6±4.6）分（P=0.000）。除内旋外,手术前后肩关节活动度和功能评分的差异均有统计学意义。 结论对于陈旧性肩关节前脱位,切开复位联合Latarjet手术可有效重建肩关节前方稳定性。同时术中正确处理伴随损伤及术后早期规范康复锻炼也是提高手术疗效的重要因素。     

Dislocation of the posterior stabilized total knee arthroplasty: A report of two cases

This brief report details the previously unreported complication of dislocation of the posterior stabilized total knee arthroplasty. Both patients had valgus deformities requiring extensive release of the contracted lateral soft tissues. The mechanism of dislocation was one of slight flexion and external rotation. The prosthetic tibial spine became locked posterior to the femoral cam. Reduction was accomplished by applying traction and anterior translation on the tibia with the knee slightly flexed. No redislocations have occurred. A literature review is presented and the authors discuss technique modifications that may prevent this complication.     

骨性和软组织性髌骨脱位模型中滑车发育的实验研究

目的通过股骨截骨术增大股骨前倾角和髌骨内外侧软组织失平衡手术制作髌骨脱位模型,观察股骨滑车局部形态和骨小梁结构的变化。方法取40只3个月龄的新西兰幼兔,分别对其右膝进行两种手术方式(每组20只):①截骨组,接受股骨旋转截骨术,股骨远端内旋来增大股骨前倾角;②软组织组,行髌骨内侧支持带松解和外侧支持带紧缩缝合术。所有左膝作为正常对照组。术后观察4个月至骨骼成熟,将股骨远端进行Micro-CT扫描,测量滑车形态:外侧髁、滑车沟和内侧髁的高度,滑车沟角,滑车的外侧和内侧关节面倾斜角等,并对骨小梁进行分析:骨体积分数、骨小梁厚度、骨小梁数量、骨小梁分离度和骨密度等。相关指标的结果进行组间比较。结果截骨组中1例发生髋关节脱位,而髌骨未发生脱位;3例在屈膝状态下出现完全性的髌骨脱位;16膝在膝关节被动伸直时,髌骨发生脱位。软组织组中15膝在屈膝状态下出现完全性的髌骨脱位,5膝未发生髌骨脱位。截骨组的股骨滑车在滑车入口处伴有局部的突起形成,称为"骨突",而滑车关节面比较光滑,未出现明显的软骨破裂等,而软组织组的股骨滑车未见"骨突"形成,滑车关节面出现软骨破裂、缺损等关节炎表现。与对照组相比,截骨组和软组织组的滑车均变浅和变宽,滑车沟高度和滑车沟角变大,但两组比较没有统计学差异。与对照组相比,截骨组骨小梁发生汇聚,内侧髁和外侧髁的骨小梁厚度增大,内侧髁骨小梁数量减少,而软组织组表现为骨质疏松,内侧髁和外侧髁的骨体积分数、骨小梁厚度、骨小梁数量和骨密度都减少,骨小梁分离度增大。与软组织组相比,截骨组内侧髁和外侧髁的骨体积分数、骨小梁厚度、骨小梁数量和骨密度都较大,骨小梁分离度较小,差异有统计学意义。结论通过股骨截骨术增大股骨前倾角和髌骨内外侧软组织失平衡手术可成功构建髌骨脱位的骨性和软组织型模型,并继发形成不同的滑车形态学改变和骨小梁结构变化。     

全髋关节置换术治疗成人髋关节发育不良的髋臼重建

目的探讨全髋关节置换术治疗成人髋关节发育不良（DDH）时不同方式髋臼重建对疗效的影响。方法 2000年1月至2007年10月,36例（44髋）先天性髋臼发育不良患者进行了全髋关节置换。年龄42～65岁,平均48岁。术前Harris评分平均为49.9分,双下肢长度差异平均为1.8 cm,髋关节平均活动度：屈曲59.6°,外展21.6°,内收13.9°,外旋10°,内旋8.2°。术中臼杯均安装于真臼处,髋臼内移14髋,髋臼内陷成形术18髋,自体股骨头结构性植骨12髋。髋臼侧均选用非骨水泥型假体。疗效评价：根据Harris评分分为优、良、可、差四级。结果所有患者均获得随访,随访时间1.8～9.2年,平均5.1年。平均Harris评分由术前的49.9分恢复到术后的90.1分,两者比较有统计学差异（P〈0.01,t=28.807）,其中评定为优23髋、良17髋、可4髋,术后优良率达90.9%。术后髋关节平均活动度：屈曲105°,外展35°,内收15.8°,外旋45°,内旋15°。本组病例无肺栓塞、深静脉血栓形成、感染等并发症发生。X线检查示假体无松动移位,无翻修病例。结论全髋关节置换术治疗成人髋臼发育不良采用恰当的髋臼重建结合非骨水泥型髋臼假体可获得满意中远期疗效。