The effect of bracing on patella alignment and patellofemoral joint contact area

PURPOSE: To examine the influence of two patellofemoral braces on pain response, patellar alignment, and patellofemoral joint contact area in persons with patellofemoral pain. METHODS: Fifteen women between the ages of 18 and 45 yr with a diagnosis of patellofemoral pain participated. After the assessment of pain response using a visual analog scale, subjects underwent axial plane magnetic resonance imaging of patellofemoral joint at 0 degrees, 20 degrees, 40 degrees, and 60 degrees of knee flexion. Imaging was done with the knee extensors contracted (25% body weight) under three conditions: 1) no brace, 2) On-Track brace, and 3) Patellar Tracking Orthosis (PTO). Measures of mediolateral patellar displacement and tilt and medial and lateral facet contact area were obtained from the magnetic resonance images. RESULTS: On average, the On-Track brace reduced symptoms by 50%, whereas the PTO reduced pain by 44%. When averaged across all knee flexion angles, the PTO and the On-Track brace significantly increased total patellofemoral joint contact area by 52.0 mm (21%) and 59.3 mm (24%), respectively, when compared with the no-brace condition. Bracing had no influence on lateral patellar tilt; however, small but significant changes in lateral patellar displacement were observed. CONCLUSION: Large changes in pain and contact area occurred without sizable changes in patellar alignment. The results of this study suggest that changes in patellar alignment by itself may not be responsible for pain alleviation after patellar bracing.     

Opening wedge high tibial osteotomy affects both the lateral patellar tilt and patellar height

In the current study, we evaluated changes in the patellofemoral joint indices in 49 knees from 39 patients (11 men and 28 women with a median age of 64 years; range 53–79) who had undergone an opening wedge high tibial osteotomy (OWHTO). Osteoarthritis had been diagnosed in 39 knees and osteonecrosis in the other 10 knees in this patient cohort. Radiographs showing anteroposterior and true lateral views of the knee joints while standing, and also skyline views while standing with a 30° flexion, were taken both pre- and postoperatively. Radiographic assessments were then performed using the following five parameters: femorotibial angle (FTA), modified Blackburne-Peel ratio (mBP), tibial slope (TS), lateral patellar tilt (LPT), and lateral patellar shift (LPS). The average LPT decreased significantly from 7.4° ± 3.7° to 5.2° ± 3.6° (P < 0.01). Patients treated with a greater than 15° correction showed a significantly bigger change in their LPT than those with corrections of 15° or less. No statistical differences were found between the preoperative (10.2 ± 4.5%) and postoperative (10.2 ± 4.7%) LPS measurements. Changes in the radiographic parameters were also observed in the patellofemoral joint after OWHTO. It is unclear to what extent the postoperative patellar shift and tilt affects the long-term clinical outcomes but our current results suggest that OWHTO negatively affects the congruency of the patellofemoral joint and should not exceed a correction of 15°.     

Patellar thickness and lateral retinacular release affects patellofemoral kinematics in total knee arthroplasty

Purpose

To study the effect of increasing patellar thickness (overstuffing) on patellofemoral kinematics in total knee arthroplasty and whether subsequent lateral retinacular release would restore the change in kinematics.

Methods

The quadriceps of eight fresh-frozen knees were loaded on a custom-made jig. Kinematic data were recorded using an optical tracking device for the native knee, following total knee arthroplasty (TKA), then with patellar thicknesses from ?2 to +4 mm, during knee extension motion. Staged lateral retinacular releases were performed to examine the restoration of normal patellar kinematics.

Results

Compared to the native knee, TKA led to significant changes in patellofemoral kinematics, with significant increases in lateral shift, tilt and rotation. When patellar composite thickness was increased, the patella tilted further laterally. Lateral release partly corrected this lateral tilt but caused abnormal tibial external rotation. With complete release of the lateral retinaculum and capsule, the patella with an increased thickness of 4 mm remained more laterally tilted compared to the TKA with normal patellar thickness between 45° and 55° knee flexion and from 75° onwards. This was on average by 2.4° ± 2.9° (p < 0.05) and 2.°9 ± 3.0° (p < 0.01), respectively. Before the release, for those flexion ranges, the patella was tilted laterally by 4.7° ± 3.2° and 5.4° ± 2.7° more than in the TKA with matched patellar thickness.

Conclusion

Patellar thickness affects patellofemoral kinematics after TKA. Although lateral tilt was partly corrected by lateral retinacular release, this affected the tibiofemoral kinematics.

Level of evidence

IV.     

Decreased ratios of lateral to medial patellofemoral forces and pressures after lateral retinacular release and gender knees in total knee arthroplasty

Purpose

To demonstrate that lateral to medial patellofemoral force and pressure ratios could be a surrogate marker of retinacular tension and patellar tracking.

Methods

The patellofemoral forces of six knees from three fresh-frozen half-body female cadavers were evaluated with a capacitive sensor under simulated operative conditions in six staged clinical scenarios: native knees, knee arthroplasty without patellar resurfacing, resurfaced knee and patella, resurfaced knee and patella with lateral release, gender-specific knee arthroplasty with patella resurfacing, and gender-specific knee arthroplasty with lateral release. Maximum force and peak pressure were simultaneously recorded during three to four ranges of motion. Average values were compared between lateral and medial patellofemoral compartments as an objective measure of patellar tracking for the different settings.

Results

Significant differences in lateral and medial force and pressure differentials were seen in most scenarios despite clinically normal patellar tracking. Lateral to medial ratios of maximum force and peak pressure significantly increased after TKA (2.9, 2.1) and after patella resurfacing (2.8, 2.6) compared to the native knee (1.6, 1.8). Addition of a lateral release in resurfaced knees decreased the ratio of lateral to medial patellofemoral forces and pressures as did gender knee arthroplasty (1.5 and 1.1, 2 and 1.3, respectively). Pressure and force values most closely resembled the native knee in the resurfaced knee/resurfaced patella with lateral release and in the gender knee arthroplasty scenarios.

Conclusions

Use of lateral to medial patellofemoral force ratios as a surrogate objective marker for patellar tracking was validated in this study by decreasing ratios observed after lateral release in TKA and with gender-specific implants.     

Dynamic magnetic resonance imaging

Among the devices helping with an accurate diagnosis, neither MRI nor arthroscopy is perfect; both delineate pathology in the knee joint with reasonable sensitivity and specificity. MRI, as a noninvasive and nonionizing modality, has made a significant contribution to the understanding of musculoskeletal disturbances. Static images through the patellofemoral joint in different degrees of flexion reveal only the degree of patellar tilt or subluxation, parameters that can be measured also on the axial view of conventional radiography. The accuracy of patellar position on static axial MRI is limited by the absence of muscle contraction, movement, and loading. Dynamic axial images of patellofemoral articulation can demonstrate the degree of flexion where patellar malalignment is maximal and assess whether or not it reduces. Arthroscopy, aside from its diagnostic values, provides the opportunity for treatment of intra-articular changes contributing to knee joint disturbances, but it is an invasive technique with potential risks of complications. The performed cost-effectiveness analysis of MRI is based mainly on estimation of intra-articular pathology of the acutely-injured knee [49,52,56]. There are scarce data on the cost-effectiveness of MRI of patellofemoral alignment in patellofemoral pain knees. Total examination time for active movement dynamic MRI procedure is approximately 8 to 10 minutes, thus it can be performed during routine MRI examination of the knee. In cases of suspected patellofemoral malalignment with symptoms that mimic other types of internal derangement of the knee joint, dynamic MRI can be a procedure of choice for detection of transient patellar dislocation, whereas a single clinical examination cannot differentiate from other internal knee pathologies. Dynamic MRI, although in an experimental phase, gives us a new perspective for dynamic study of the patellofemoral joint.     

髌骨倾斜导致髌股关节接触压力与面积改变

我们采用压敏片测量技术对髌骨倾斜状态下髌股关节的生物力学变化特点进行了研究。７例新鲜人尸体标本采用手术方法将髌外侧支持带紧缩造成髌骨外侧倾斜状态，超低压型压敏片置于髌股关节之间，等长加载２００Ｎ，分别在正常状态及髌骨倾斜状态下于屈膝３０°、６０°、９０°、１２０°时测量髌股关节接触压力与面积。结果表明：髌骨倾斜后使髌股关节原正常的“哑铃型”接触压迹转变为“彗星尾状”，外侧面孤立接触，内侧面接触区减少或失接触，接触压力改变表现为髌内侧软骨面接触压力减少或消失，外侧面接触压力集中且明显增高上述改变均以屈膝３０°时最明显。实验结果提示：各种纠正髌骨倾斜状态及治疗髌骨软骨软化症的手术方法，必须以恢复髌骨内外侧关节面压力平衡为标准，特别是屈膝３０°时病理力学的改善最为重要     

Effect of bracing on patellar kinematics in patients with patellofemoral joint pain

PURPOSE: Bracing is commonly used to correct patellar malalignment syndromes. However, there are little objective data documenting the effect of such supports on patellofemoral joint relationships. The purpose of this study was to assess the effectiveness of an elastic patellofemoral sleeve brace in altering patellar tracking in subjects with patellofemoral pain. METHODS: Ten female subjects (12 patellofemoral joints) between the ages of 17 and 46 participated in this study. All subjects had a diagnosis of patellofemoral pain and demonstrated lateral patellar tracking based on magnetic resonance imaging (MRI) assessment. Each subject underwent kinematic MRI of the patellofemoral joint through a range of 45 to 0 degrees of knee flexion against a resistance of 15% body weight. Imaging was performed with and without a patellofemoral joint brace (Bauerfeind Genutrain P3 brace, Atlanta, GA). Measurement of medial/lateral patellar displacement, medial/lateral patellar tilt, and the depth of the trochlear groove (sulcus angle) were obtained with midpatellar image sections at 45, 36, 27, 18, 9 and 0 degrees of knee flexion. RESULTS: No statistically significant differences in medial/lateral patellar displacement or tilt were found between braced and unbraced trials across all knee flexion angles (P < 0.05). A small but statistically significant increase in sulcus angle was found across all knee flexion angles with the braced trials (P > 0.05). CONCLUSIONS: These results do not support the hypothesis that the brace used in this study corrects patellar tracking patterns in subjects with patellofemoral pain. However, the increased sulcus angle indicates a change in patella position within the trochlea. It is possible that the clinical improvements seen with bracing may be the result of subtle differences in joint mechanics and not gross changes in alignment.     

The effect of femoral component rotation on the kinematics of the tibiofemoral and patellofemoral joints after total knee arthroplasty

Purpose  

Complications after total knee arthroplasty (TKA) often involve the patellofemoral joint, and problems with patellar maltracking or lateral instability have sometimes been addressed by external rotation of the femoral component. This work sought to measure the changes of knee kinematics caused by TKA and then to optimise the restoration of both the patellofemoral and tibiofemoral joint kinematics, by variation of femoral component internal–external rotation.     

Evidence of abnormal anteroposterior patellar tilt in patients with patellar tendinitis with use of a new radiographic measurement

BACKGROUND: A number of clinical conditions of the patellofemoral joint have been correlated with abnormal patellofemoral radiographic measurements. HYPOTHESIS: An abnormal anteroposterior patellar-tilt angle may be a contributing factor to pathologic conditions of the knee. STUDY DESIGN: Prospective nonrandomized clinical trial. METHODS: The anteroposterior patellar-tilt angle was measured in cadaveric knees to determine the best knee position. The radiographs of normal subjects and patients with patellar tendinitis or patellofemoral pain syndrome were examined for differences in patellar-tilt angle. RESULTS: Cadaveric measurements demonstrated highest intertester and intratester reliability at 30 degrees of knee flexion and neutral femoral rotation. Intratester measurements on normal subjects exhibited high reliability, with a mean anteroposterior tilt angle of 30.8 degrees +/- 6.7 degrees. In the patellofemoral pain group the mean anteroposterior tilt angle was 29.1 degrees +/- 8.5 degrees; however, for patients with patellar tendinitis, it was 25.6 degrees +/- 7.0 degrees, significantly lower than in the normal population. Furthermore, there was no difference between the angles of involved and uninvolved knees of patients with unilateral patellar tendinitis. CONCLUSION: The anteroposterior patellar-tilt angle is a clinically reliable measurement of patellar tilt in the sagittal plane that can be used to study patellofemoral tilt in a variety of clinical situations. The results of this study demonstrate that patients with patellar tendinitis have abnormal patellar tilt in the sagittal plane.     

Axial and lateral radiographs in evaluating patellofemoral malalignment.

This is a prospective study of 431 patients (862 knees) with patellofemoral pain, patellar dislocation, or other abnormalities of the knee joint. There were 217 asymptomatic knees with no contralateral problems for comparison. All patients had a history and physical and radiographic examination of both knees. The radiographs included standard anteroposterior views, axial views at 30 degrees of knee flexion, and standing lateral views at 0 degree and 30 degrees of flexion. The presence of patellar tilt or subluxation was noted on the axial view. The lateral view of the patella, with precise overlap of the posterior femoral condyles, allowed determination of relationships between the patella's medial edge, median ridge, and lateral edge to assess patellar tilt. Sixty-two percent of patients with patellar dislocations demonstrated subluxation on the axial view, while 98% demonstrated an abnormal lateral view. Eighteen percent of the control knees revealed evidence of subluxation on the axial view while 35% demonstrated subluxation on the extended lateral view. The axial view demonstrated 62% sensitivity for dislocation, while the lateral view taken in full extension demonstrated 98% sensitivity. The specificity for previous dislocation was 82% for the axial view and 93% for the lateral flexed view. Given the high sensitivity of the lateral view for detecting prior patellar dislocation, a normal result on this view can virtually eliminate the question of previous dislocation. Also, with the high specificity of the axial view and lateral view with knee flexion, the two views combined can confirm a clinical impression of patellofemoral malalignment.     

Effect of patellar brace on patellofemoral relationships

The effect of patellar brace on patellofemoral relationships was analyzed using magnetic resonance imaging in 17 knees with patellar subluxation or dislocation. Images were produced in 0° and 20° knee flexions without the patellar brace, with patellar brace and with patellar brace after 1 h of walking. In knee extension, the patellar brace had an unfavorable effect on lateral patellar tilt, but decreased the tilt in 20° knee flexion. The excessive lateral patellar displacement was alleviated in both knee flexion angles. The corrected position was still apparent after physical exercise. Isometric quadriceps muscle contraction increased the displacement. These results suggest a positive stabilizing effect of the brace in patients with patellar instability.     

The effects of weight-bearing conditions on patellofemoral indices in individuals without and with patellofemoral pain syndrome

Objective

The purpose of this study is to evaluate differences between the patellofemoral joint indices after supine, non-weight-bearing and standing position, and weight-bearing Merchant view radiographs in individuals without and with patellofemoral pain syndrome (PFPS).

Materials and methods

Radiographs of 44 knees without PFPS and 51 knees with PFPS were retrospectively evaluated. In both positions, the non-weight-bearing and weight-bearing Merchant views, patellar indices such as patellar tilt angle, lateral patellofemoral angle, lateral subluxation distance, lateral patellar displacement, and congruence angle were measured, respectively. The differences between the patellofemoral joint indices in knees with and without PFPS were analyzed using univariate and multivariate regression analysis, in regards to correlation factors.

Results

The patellar tilt angle (p?=?0.0002), lateral subluxation distance (p?=?0.038), lateral patellar displacement (p?=?0.0004), and congruence angle (p?<?0.0001) on the weight-bearing Merchant view was significantly decreased in normal knees without PFPS. In pathologic knees with PFPS, the patellar tilt angle (p?<?0.0001), lateral subluxation distance (p?<?0.0001), lateral patella displacement (p?<?0.0001), and congruence angle (p?<?0.0001) on weight-bearing Merchant view was also significantly decreased. The difference between the patellofemoral indices was significantly more in knees specifically with PFPS (p?<?0.05).

Conclusions

These results suggest that patellofemoral indices measured during non-weight-bearing supine position do not sufficiently represent the patellofemoral kinematics during normal weight-bearing activities. We conclude that this study establishes the clinical significance and relevance of assessing the patellofemoral kinematics by weight-bearing, standing Merchant view radiographs, when evaluating patients with patellofemoral problems.     

Evaluation of the patellofemoral joint with kinematic MR fluoroscopy

OBJECTIVE: The aim of this study was to evaluate the diagnostic effectiveness of kinematic magnetic resonance fluoroscopy (KMRF) on patients with patellofemoral incongruency. MATERIALA AND METHODS: 17 patients (20 knees) and 10 healthy volunteers (20 knees), all men (mean age 29.4 years, S.D. 9, range 16-50), were included to our study. Only male subjects were studied because of potential biomechanical differences between sexes. KMRF was used to perform kinematic MR imaging of patellar alignment and tracking in 10 healthy subjects and 17 patients with a provisional clinical diagnosis of abnormal patellofemoral joints. The patellofemoral joints were examined with the knee in different angles of active flexion. At each knee position, real time kinematic and axial MRF image was used to focus on the sagittal plane, followed by an axial image focused through the middle of the patella. Three angles were measured: patellar tilt angle (PTA), sulcus angle (SA) and congruence angle (CA). RESULTS: Five patterns of malalignment were identified and studied. Two patellofemoral joints were normal, 10 had lateralization of the patella, 2 had patellar tilt, 2 had lateralization and patellar tilt (i.e. excessive lateral pressure syndrome) and 4 had medialization of the patella. CONCLUSION: KMRF is an effective method in evaluating patellofemoral incongruency. Short time duration of investigation, ability to get nearly real time images, suitable temporal contrast resolution and investigation from very different angles of knee are important advantages of the method.     

Long patellar tendon: radiographic sign of patellofemoral pain syndrome--a prospective study.

The position of the patella was studied prospectively in both knees of 45 consecutive patients (21 male and 24 female patients aged 16-48 years who were competitive [n = 17] or recreational [n = 28] athletes) who had unilateral patellofemoral pain syndrome without symptoms or signs of patellar instability at initial examination. In each knee, standardized anteroposterior, lateral, and tangential radiographs were obtained and six indexes of patellar position (the ratio of the patellar tendon to the greatest diagonal length of the patella, sulcus angles, lateral patellofemoral angle, lateral patellar displacement, patellofemoral index, and knee angle) were measured. When healthy and affected knees were compared, high riding of the patella due to long patellar tendon (patella alta) was the only definite finding in the affected knees. The shape of the intercondylar sulcus and the mediolateral position of the patella were identical in both knees, providing no evidence for patellofemoral incongruence or lateral patellar tilt. Results of this study strongly suggest that idiopathic retropatellar pain is closely associated with patella alta.     

Arthroscopically assisted medial reefing without routine lateral release for patellar instability

BACKGROUND: Patellofemoral instability in patients with normal alignment has been effectively treated with medial reefing procedures and a lateral release. Recent research suggests that a lateral release may not be necessary in patients without excessive patellar tilt. HYPOTHESIS: Arthroscopically assisted medial reefing without lateral release is as effective as techniques with a lateral release reported in the literature. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-four patients (25 knees) were observed for an average of 60 months. Preoperatively, patients underwent a history, physical examination, and radiographic evaluation. At follow-up, a physical examination and radiographic evaluation were repeated. Preoperative and postoperative Lysholm and Tegner scores were calculated. A subjective questionnaire was also completed. Comparative statistics were used for the preoperative and postoperative scores (P < .05). RESULTS: Ninety-six percent (24/25) were satisfied with their results, and all patients would have the same procedure performed again. Subjective symptom scores improved significantly. Lysholm knee scores improved from an average of 54 to 91 (P < .001). Tegner activity level improved from an average of 3.3 to 6.2 (P < .001). Significant improvement was seen in patellar mobility, apprehension, and patellofemoral tenderness with compression. Range of motion, muscle atrophy, and tilt did not change significantly. Congruence angles improved from 4.4 degrees to -2.5 degrees (P = .009), lateral patellofemoral angles improved from 5.5 degrees to 8.7 degrees (P = .011), and lateral patellar displacement improved from 2.0 to 0.2 mm (P < .044). There were no recurrent dislocations or subluxations. CONCLUSION: Arthroscopically assisted medial reefing, without lateral release, is an effective treatment for patients with recurrent patellofemoral instability and normal alignment.     

Magnetic resonance imaging of patellofemoral relationships

Patellofemoral relationships were analyzed in 11 patients (13 knees) with patellar dislocation and 15 asymptomatic subjects (15 knees) at 0° and 20° of flexion. The measurements were made from five consecutive axial images through the patellofemoral joint. The six indices measured were lateral patellar tilt (LPT), lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), patella-lateral condyle index (L/PW), congruence angle (CA), and sulcus angle (SA). The reproducibility of the method was evaluated. The difference between the two study groups was more evident at 0° than at 20° of knee flexion. Significant differences were noted between measurements made at different levels of the joint, particularly in the controls. Isometric contraction of the quadriceps muscle lateralized and tilted the patella slightly in both groups. L/PW with and without quadriceps muscle contraction, and LPA with reference to the anterior condyles differentiated between the two study groups most clearly. LPT and LPA with reference to the anterior condyles differentiated the study groups better than LPT and LPA with reference to the posterior condyles. The reproducibility was good except for inter-observer comparison of CA and SA. The use of an imaging plane selected at the midpoint of the patellar articular cartilage increases the sensitivity of the measurements, since it takes into account both the height of the patella and the tendency towards lateralization. These results indicate that patellar tilt is best measured with the LPA index and patellar lateralization with the L/PW index at 0° knee flexion. This study should always include isometric contraction of the quadriceps muscle.     

Effect of patellar tendon shortening on tracking of the patella

BACKGROUND: Although 10% postoperative patellar tendon shortening after bone-patellar tendon-bone autograft reconstruction of the anterior cruciate ligament has been reported, there are no published studies assessing the effect of shortening on patellofemoral joint biomechanics under physiological loading conditions. PURPOSE: To investigate the influence of patellar tendon shortening on patellofemoral joint biomechanics. STUDY DESIGN: Controlled laboratory study. METHODS: The authors evaluated the patellofemoral contact area, the location of contact, and the patellofemoral joint reaction force and contact stresses in 7 cadaveric knees before and after 10% patellar tendon shortening. Shortening was achieved using a specially designed device. Experimental conditions simulating those occurring during level walking were employed: physiological quadriceps loads and corresponding angles of tibial rotation were applied at 15 degrees , 30 degrees , and 60 degrees flexion of the knee. Patellofemoral joint contact areas were measured before and after shortening using the silicone oil-carbon black powder suspension squeeze technique. RESULTS: After patellar tendon shortening, patellofemoral joint contact areas were displaced proximally on the patellar surface and distally on the femoral surface. Although the contact area increased by 18% at 15 degrees of knee flexion (P = .04), no significant change occurred at 30 degrees or 60 degrees of knee flexion (P > .05). Patellofemoral contact stress remained unchanged after patellar tendon shortening (P > .05) at each flexion angle. CONCLUSION: Our results suggest that a 10% shortening of the patellar tendon does not alter patellar contact stresses during locomotion. It is not clear whether apparent changes in contact location in all positions and contact area at 15 degrees would have clinical consequences.     

Trochlear osteotomy for patellar instability: satisfactory minimum 2-year results in patients with dysplasia of the trochlea

Trochlear dysplasia is a predisposing factor for recurrent patellar instability. We evaluated the results of an anterior lateral femoral condyle open wedge osteotomy for treating patellar instability. A total of 16 consecutive patients (19 knees) with symptoms of recurrent patellar instability and trochlear dysplasia identified using a true lateral radiograph of the knee underwent an anterior lateral femoral osteotomy. Outcomes were documented at 2 years minimum follow-up using the Lysholm scale, the patellofemoral score, WOMAC score and standard conventional radiographs. In 17 knees, patients reported good improvement in stability (no dislocations) and most patients had a marked improvement in pain and functional scores at follow-up (mean follow-up 51 months). No serious complications occurred. Anterior femoral osteotomy of the lateral condyle appears to be a satisfactory and safe method for treating patients with patellofemoral joint instability caused by trochlea dysplasia. In selected cases this procedure can be used to correct trochlea dysplasia. In our opinion, the key to a successful treatment of patellofemoral instability is to successfully distinguish the anatomic deficiencies and to correct the anatomical abnormality.     

军事训练所致外侧髌股挤压综合征的临床研究

目的 探讨军事训练所致外侧髌股挤压综合征的诊断方法及手术治疗效果.方法 收集2006年5月-2008年5月收治的军事训练所致外侧髌股挤压综合征患者15例(病例组),男12例(14膝),女3例(3膝),年龄22～43岁,平均27.3岁.以随机抽取的18名年龄性别匹配、无膝痛症状的健康志愿者作为对照组.两组患者均接受膝关节正侧位及髌骨轴位X线片检查,观察膝关节骨质结构情况,测量滑车角、适合角及髌股指数并进行组间比较.病例组患者均实施髌外侧支持带松解术,并对术前和术后疼痛程度(VAS法)进行评估.结果 病例组适合角(7.67°±5.81°)及髌股指数(2.49±1.40)均明显大于对照组(适合角-2.2°±-2.71°,髌股指数1.25±0.15),差异有统计学意义(P＜0.01,P＜0.05),而滑车角(132.44°±10.21°)与对照组(136.80°±4.87°)比较差异无统计学意义(P＞0.05),且病例组膝关节骨质结构改变明显.病例组术前疼痛程度评分为7.06±0.85,明显高于术后6个月(3.87±0.24)及术后1年(3.01±0.17),差异有统计学意义(P＜0.05),而术后6个月与术后1年的疼痛程度评分差异无统计学意义(P＞0.05).结论 军事训练所致外侧髌股挤压综合征的诊断需结合病史、典型临床症状、体征及X线检查并注意鉴别诊断.膝关节X线片是诊断外侧髌股挤压综合征最基本的辅助检查手段,其中髌股指数应用方便.     

The patella and tibial condyle position after combined and after closing wedge high tibial osteotomy

High tibial osteotomy changes the patella and tibial condyle position, which makes the subsequent total knee replacement technically demanding. From 1 January 1993 to 31 December 2000, combined osteotomy [After the first osteotomy made 2 cm distally to the joint line, a bone wedge is removed based laterally. Its tip ends at the center of the tibial condyle (half bone wedge). The distal part of the tibia is placed into the valgus position and the half bone wedge is placed into the gap opened medially.] was performed on 103 knees and closing wedge osteotomy was performed on 47 consecutive knees. Eighty combined (group A) and 41 closing wedge (group B) osteotomy were studied. All knees were assessed radiologically before surgery, in the 10th postoperative week, in the 12th postoperative month and at the time of the final follow-up (in group A—66.15 months, in group B—66.61 months). We examined the change of the femorotibial angle, of the patellar height according to the method of Insall and Salvati, of the tibial slope angle according to the method of Bonnin, of the tibial condylar offset according to the method of Yoshida and of the distance between the lateral tibial plateau and the top of the fibular head. In group A and B, the recurrence of the varus deformity was not noted and valgus alignment did not increase in any case. In group-A, the Insall–Salvati ratio remained unchanged in 65% of knees. The tibial slope angle decreased in both groups. There was correlation between the change of the tibial condylar offset and the angle of the correction in both groups. There was correlation between the change of the distance between the lateral tibial plateau and the top of the fibular head. After combined osteotomy, the transposition of the tibial condyle and the decrease of the distance between the lateral tibial plateau and the top of the fibular head was less than after closing wedge osteotomy, although the average angle of correction was more after combined osteotomy (11.835°), than after closing wedge osteotomy (9.465°). Theoretically, the recurrence of the varus deformity, the increase of the valgus alignment and (in majority of cases) the shortening of the patellar tendon do not compromise the likelihood of successful conversion to the subsequent total knee replacement, either after combined or after closing wedge osteotomy. The combined osteotomy does not lead to considerable transposition of the tibial condyle and to considerable lateral tibial bone loss; therefore, theoretically, the combined osteotomy does not impair the subsequent total knee replacement.