Can T2 relaxation values and color maps be used to detect chondral damage utilizing subchondral bone marrow edema as a marker?

Objective  This study aimed to investigate whether a commercially available time-efficient T2 mapping sequence will demonstrate findings of articular cartilage degeneration based on T2 relaxation values (RV) and color maps, using subchondral bone marrow edema (BME) as a marker for chondral damage. Materials and methods  The patient group consisted of 88 subjects who underwent knee magnetic resonance imaging at 1.5 T who had subchondral BME evident on fat-suppressed T2-weighted sequences. The control group was comprised of 60 subjects with no evidence of subchondral BME. A commercially available eight echo T2 relaxation sequence (acquisition time 8:36 min) was used to construct a T2 color map and to determine T2 RVs. T2 RVs were determined on cartilage overlying subchondral BME in patients and in eight pre-determined anatomical regions in controls. T2 color maps in the patient and control groups were analyzed for degree of color stratification (presence = two or more colors) at the same anatomic site as that used for T2 RV determination. Results  T2 RVs were significantly increased in patients compared to controls for the medial femoral condyle (MF; p < 0.01), medial patellar facet (MP; p < 0.01), lateral patellar facet (LP; p < 0.01), lateral femoral condyle (LF; p < 0.01) and lateral tibial plateau (LT; p < 0.01). Loss of color stratification was noted in patients compared to controls in the medial tibial plateau (MT; p = 0.01), LF (p < 0.01), and LT (p < 0.01). In the patient group, increase in T2 RVs was associated with corresponding decrease in color stratification in MF (p < 0.01), MT (p < 0.01), MP (p < 0.01), medial femoral trochlear groove (p = 0.02), and lateral femoral trochlear groove (p < 0.01). Conclusion  Subchondral BME was associated with an increase in adjacent articular cartilage T2 RVs at some sites. Also, elevated T2 RVs were associated with loss of color stratification.     

Arthroscopic evaluation of trochlear dysplasia as an aid in decision making for the treatment of patellofemoral instability

Purpose

Trochlear dysplasia is an important aetiological factor for the development of patellofemoral instability (PFI). The aim of the study was to identify the arthroscopic morphology of trochlear dysplasia that can be helpful when planning operative treatment for PFI.

Methods

Magnetic resonance imaging (MRI) scans and strict lateral radiographs of 46 patients treated for PFI were assigned according to Dejour and matched with arthroscopic views from the lateral superior arthroscopic portal. On arthroscopy, signs of trochlear dysplasia were identified and classified into two types. Intra- and inter-observer agreements of the arthroscopic evaluation were assessed.

Results

Arthroscopically, 2 major types of trochlear dysplasia could be distinguished. Type I shows a flat trochlear groove with an elevated trochlear floor in relation to the anterior femoral cortex. In type II, the proximal trochlea was convex with a lateral trochlear bump. Arthroscopic evaluation was not consistent with the Dejour’s radiographic and axial MRI classification. Arthroscopic grading showed excellent intra- and inter-observer agreements (81–92 %).

Conclusion

Arthroscopic evaluation can give additional information about the severity of trochlear dysplasia. This additional information can be used as an aid in decision making for the treatment of PFI.

Level of evidence

II.     

Evaluation of grades 3 and 4 chondromalacia of the knee using T2*-weighted 3D gradient-echo articular cartilage imaging

Objective. To determine the accuracy of T2*-weighted three-dimensional (3D) gradient-echo articular cartilage imaging in the identification of grades 3 and 4 chondromalacia of the knee. Design and patients. A retrospective evaluation of 80 patients who underwent both arthroscopic and MRI evaluation was performed. The 3D images were interpreted by one observer without knowledge of the surgical results. The medial and lateral femoral condyles, the medial and lateral tibial plateau, the patellar cartilage and trochlear groove were evaluated. MR cartilage images were considered positive if focal reduction of cartilage thickness was present (grade 3 chondromalacia) or if complete loss of cartilage was present (grade 4 chondromalacia). Comparison of the 3D MR results with the arthroscopic findings was performed. Results. Eighty patients were included in the study group. A total of 480 articular cartilage sites were evaluated with MRI and arthroscopy. Results of MR identification of grades 3 and 4 chondromalacia, all sites combined, were: sensitivity 83%, specificity 97%, false negative rate 17%, false positive rate 3%, positive predictive value 87%, negative predictive value 95%, overall accuracy 93%. Conclusion. The results demonstrate that T2*-weighted 3D gradient-echo articular cartilage imaging can identify grades 3 and 4 chondromalacia of the knee. Received: 18 April 2000 Revision requested: 18 July 2000 Revision received: 10 October 2000 Accepted: 27 November 2000     

Spectrum of T2* values in knee joint cartilage at 3 T: a cross-sectional analysis in asymptomatic young adult volunteers

Objective

To establish baseline T2* values in healthy knee joint cartilage at 3 T.

Materials and Methods

Thirty-four volunteers (mean age: 24.6?±?2.7 years) with no history or clinical findings indicative of any knee joint disease were enrolled. The protocol included a double-echo steady-state (DESS) sequence for morphological cartilage evaluation and a gradient-echo multi-echo sequence for T2* assessment. Bulk and zonal T2* values were assessed in eight regions: posterior lateral femoral condyle; central lateral femoral condyle; trochlea; patella; lateral tibial plateau; posterior medial femoral condyle; central medial femoral condyle; and medial tibial plateau. Statistical evaluation comprised a two-tailed t test and a one-way analysis of variance to identify zonal and regional differences.

Results

T2* mapping revealed higher T2* values in the superficial zone in all regions (P values?≤?0.001) except for the posterior medial femur condyle (P?=?0.087), and substantial regional differences demonstrating superior values in trochlear cartilage, intermediate values in patellar and central femoral condylar cartilage, and low T2* values in posterior femoral condylar cartilage and tibial plateau cartilage.

Conclusion

Substantial regional differences in T2* measures should be taken into consideration when conducting T2* mapping of knee joint cartilage.     

MR imaging of post-traumatic articular cartilage injuries confined to the femoral trochlea. Arthroscopic correlation and clinical significance

OBJECTIVE: To assess and describe post-traumatic articular cartilage injuries isolated to the trochlear groove and provide insight into potential mechanism of injury. MATERIALS AND METHODS: We retrospectively evaluated MR imaging findings of all knee MRIs performed at our institution over the last 2 years (2450). Thirty patients met the criteria of a cartilage injury confined to the trochlear groove. In 15 cases, which were included in our study, arthroscopic correlation was available. Each plane was evaluated and graded for the presence and appearance of articular cartilage defects using a standard arthroscopic grading scheme adapted to MR imaging. Any additional pathological derangement was documented and information about the mechanism of injury was retrieved by chart review. RESULTS: In all cases the cartilaginous injury was well demonstrated on MRI. In 13 patients additional pathological findings could be observed. The most frequently associated injury was a meniscal tear in nine patients. In eight cases, the arthroscopic grading of the trochlear injury matched exactly with the MRI findings. In the remaining seven cases, the discrepancy between MRI and arthroscopy was never higher than one grade. In 13 out of 15 of patients trauma mechanism could be evaluated. Twelve patients suffered an indirect twisting injury and one suffered a direct trauma to their knee. CONCLUSION: The findings of this study demonstrate that MR imaging allows reliable grading of isolated injury to the trochlear groove cartilage and assists in directing surgical diagnosis and treatment. These injuries may be the only hyaline cartilage injury in the knee and meniscal tears are a frequently associated finding. Therefore, it is important to search specifically for cartilage injuries of the trochlear groove in patients with anterior knee pain, even if other coexistent pathology could potentially explain the patient's symptoms.     

Minimal rotation aberrations cause radiographic misdiagnosis of trochlear dysplasia

Radiologic criteria are commonly used to diagnose femoral trochlear dysplasia causing patellofemoral (sub)luxations. A dysplastic trochlea can be identified on conventional radiographs when the line of the trochlear groove crosses the anterior border of one or both condyles. The aim of this study was to establish the influence of rotation on the precision of these radiographic criteria as classified on a true lateral conventional radiograph. In a radiological in vitro study using two different distal femurs we found that rotation deviations of the distal femur can simulate femoral trochlear dysplasia in a normal knee. In case of trochlear dysplasia, rotational deviations can simulate a normal trochlear shape with crossing of the trochlear groove with the anterior border of the femoral condyle. Even a rotation deviation of 5° can cause a false-positive or false-negative diagnosis. We recommend the use of fluoroscopy to obtain a true lateral view (with both condyles overlapping on the posterior side) in order to correctly classify trochlear dysplasia and would strongly urge that no surgery should be performed on the basis of rotated conventional radiographs.     

Subchondral bone infractions in acute ligamentous knee injuries demonstrated on bone scintigraphy and magnetic resonance imaging.

Bone scintigraphy is used to detect radiographically silent fractures. Magnetic resonance imaging (MRI) is currently used to screen knee injuries for cartilage and ligament damage. MRI also delineates bone marrow and fractures. We investigated the bone scintigraphic findings in patients who had subchondral bone injuries demonstrated on MRI. Thirteen patients underwent MRI, three-phase bone scintigraphy with SPECT, and arthroscopic surgery after sustaining acute traumatic hemarthrosis of a knee. They all had clinically unsuspected subchondral bone injuries demonstrated on MRI with normal radiographs and normal overlying articular cartilage at arthroscopy, consistent with occult fractures. All showed focal bone repair on scintigraphy. Two of the 13 patients showed additional bone injuries only on bone scan. Two other patients scintigraphically showed focal bone repair at the medial femoral condyle due to avulsion of the medial collateral ligament. SPECT was easier to interpret than multi-view planar imaging. Bone scintigraphy confirms subchondral fractures demonstrated on MRI but also demonstrates ligament avulsion injuries and additional more subtle bone injuries.     

微骨折术治疗膝关节软骨损伤修复效果T2 star mapping评价研究

目的 本研究应用MRI对关节镜下微骨折法治疗膝关节软骨损伤修复效果进行大体组织形态学评估及定量分析.方法 本研究纳入14例有膝关节软骨损伤症状并接受关节镜下微骨折法治疗的病例进行回顾性病例分析.所有病例的关节软骨损伤均为ICRS分级Ⅲ或Ⅳ,术中测量病变面积为2～8cm^2.1年随访期内所有病例都接受常规MRI序列及T2 star mapping序列扫描（1.5T）.对损伤修复区域采用软骨组织修复磁共振观察评分系统（MOCART）进行评价.采用T2 star mapping序列扫描图像感兴趣区划分的方法对修复区域及自身正常软骨所测量的T2＊弛豫值进行分析比较.结果 1年随访期软骨修复区MOCART评分为59.50±23.90,相邻本体软骨组织评分为65.21±21.84,与软骨修复组间比较无显著差异.软骨修复区和邻近正常自体软骨组织T2＊弛豫时间分别为（31.14±9.26）ms和（32.93±11.69）ms,修复区软骨组织质地与正常软骨组织相近.结论 经关节镜下微骨折法修复膝关节软骨损伤后1年随访观察期内,MRI软骨扫描可见软骨损伤区填充良好.经T2＊测量值分析证实软骨修复组织可以达到与邻近正常透明软骨相近的组织结构.     

Is there a relationship between anterior knee pain and femoral trochlear dysplasia? Assessment of lateral trochlear inclination by magnetic resonance imaging

It may be very difficult to diagnose the pathology in patients with anterior knee pain. Patients with chronic anterior knee pain have been reviewed for the study. Our aim was to delineate the presence of subtle trochlear dysplasia by measuring lateral trochlear inclination (LTI) in axial magnetic resonance imaging (MRI) scans. While there were 109 knees in the study group with anterior knee pain (AKP), control group consisted of 74 knees without AKP. The LTI measurements were performed at the level of proximal cartilaginous area of trochlear groove in axial scans. The condition was termed to be trochlear dysplasia when LTI was below 11o. Parameters in both groups were statistically analyzed and compared for their association with LTI. There was no significant difference between LTI values of male and female subjects in each group. The mean LTI values in anterior knee pain and control groups were 17.32o and 21.5o, respectively, and the difference was statistically significant (P < 0.05). The ratio of knees with trochlear dysplasia was 16.5% in AKP group, which was only 2.7% in control. In the AKP group, the ratio of trochlear dysplasia was significantly high (P < 0.05). Although trochlear dysplasia has been generally detected in cases with patellar instability, this study revealed that the frequency of this finding in patients with other causes of anterior knee pain was also considerably high. Measurement of lateral trochlear inclination in axial MRI scans with radiologic assessment seems to be a valuable diagnostic criterion, especially in patients in whom etiology of anterior knee pain could not be identified.     

T1 mapping联合常规MRI扫描方案评估膝关节软骨损伤

目的评估在常规MRI扫描方案中加入T1 mapping成像能否提高对膝关节软骨损伤的诊断效能。方法选取86例患者的88个膝关节接受了膝关节MRI检查和关节镜检查。MRI检查采用常规方案并加入T1 mapping成像。术前2位影像科医师对所有MRI检查图像进行一致的诊断,评估是否存在软骨损伤并进行软骨损伤MRI分级,首先评估常规MRI扫描方案的图像,然后评估T1 mapping联合常规MRI扫描方案的图像。由1位骨科医师在关节镜下进行软骨损伤关节镜分级并作为金标准。计算两种MRI扫描方案评估软骨损伤的敏感度和特异度,统计分析两种扫描方案的诊断结果是否存在差异。结果关节镜检出的256个软骨损伤,常规MRI扫描方案的敏感度、特异度分别为59.0%和98.6%,T1 mapping联合常规MRI扫描方案的敏感度、特异度分别为85.9%和93.2%。T1 mapping联合常规MRI扫描方案显著提高了MRI扫描诊断早期关节软骨损伤的敏感度,关节镜1级软骨损伤的敏感度从18.6%提高至71.2%,关节镜2A级软骨损伤的敏感度从74.3%提高至94.3%。上述两种扫描方案的结果差异均有统计学意义(P<0.05)。结论常规MRI扫描方案中加入T1 mapping成像,可提高对膝关节软骨损伤的敏感度,为临床诊断早期膝关节软骨损伤提供影像学依据。     

急性髌骨外侧脱位患者性别、年龄、解剖参数与髌股关节软骨损伤的相关性

目的 探讨急性髌骨外侧脱位(lateral patellar dislocation,LPD)患者性别、年龄、髌股关节解剖参数与髌股关节软骨损伤的相关性.方法 回顾性分析2015-01至2021-07在武警山东总队医院就诊的115例经临床证实为急性LPD患者的MRI资料,对患者性别、年龄[分为青少年(<18岁)、成人(...     

Internal fixation for osteochondritis dissecans of the knee

Eight knees of seven patients with osteochondritis dissecans of the knee underwent internal fixation of the fragments. The affected location was the medial femoral condyle in four knees, the lateral femoral condyle in one knee and the patellar groove in three knees. At the time of surgery, patient age ranged from 13 to 20 years (mean 16.9 years). Open reduction and internal fixation of the unstable fragments was performed with autologous bone pegs in one knee. In the other seven knees, the procedures were carried out with biodegradable poly-L-lactide pins. At a mean follow-up of 5 years (range 4–6.8 years), seven fragments were united, whereas one knee required arthroscopic removal of the loose fragment. Neither effusion nor synovitis was noticed in any of the patients treated with biodegradable pins. The technique is simple and provides satisfactory results, suggesting a valid option for the treatment of osteochondral defects where possible.     

Autologous chondrocyte implantation versus microfracture for knee cartilage injury: a prospective randomized trial, with 2-year follow-up

The objective was to evaluate the functional performance over a 2-year period following autologous chondrocyte implantation (ACI) in an open knee procedure compared to microfracture. Objective functional outcome was studied as secondary analysis in a subgroup of patients, in a randomized clinical trial, with concealed allocation and independent evaluators. Sixty-seven patients with local cartilage defect, with a mean size of 2.4 cm2 (SD 1.5) of the femoral condyle of the knee were included. Thirty-three patients underwent the microfracture and 34 the ACI procedure. An identical rehabilitation protocol was implemented for both groups. Active knee flexion and extension range, anterior laxity, knee extension strength (concentric at 60°/s) and single leg hop performance (single hop, crossover triple hop and 6 m timed hop test) were evaluated pre-surgery and at 6, 9,12 and 24 months post-surgery. We calculated the symmetry index for individual and four performance tests pooled. Mixed linear model analyses were used with confidence interval set at 95%. The change over 2 years for the pooled performance-based tests was comparable between the two treatment arms. At 2 years, 70% (38/54) of all patients returned to >85% symmetry in overall functional performance. A decrease in functional performance at 6 months following ACI resulted in slower recovery at 9 and 12 months compared to microfracture. Rehabilitation following both cartilage repair procedures is a lengthy process. At 2 years after surgery, ACI patients have similar overall functional outcome compared to microfracture patients.     

急性前交叉韧带断裂合并膝关节骨挫伤的临床研究

目的 :总结前交叉韧带急性断裂时骨挫伤的不同类型和分布 ,探讨骨挫伤与关节软骨损伤的关系。方法 :回顾性研究 37例前交叉韧带急性断裂合并膝关节骨挫伤患者的影像学和临床资料 ,分析前交叉韧带急性断裂时骨挫伤的MRI不同表现类型、分布以及关节镜下软骨损伤的情况。结果 :MRI显示本组病例骨挫伤共 5 7处 ,其中Ⅰ型 1 4处 (2 4 .6 %) ,Ⅱ型 32处 (5 6 .1 %) ,Ⅲ型 3处(5 .3%) ,Ⅳ型 6处 (1 0 .5 %) ,Ⅴ型 2处 (3.5 %)。共 5 4处 (94 .7%)骨挫伤位于外侧间室 ,其中股骨外髁骨挫伤 31处 ,胫骨外侧平台骨挫伤 2 3处。经关节镜下手术发现 9处 (1 5 .8%)骨挫伤部位有软骨损伤表现。结论 :急性前交叉韧带断裂时 ,骨挫伤通常发生在外侧间室 ,尤其集中在外侧股骨髁前部以及外侧胫骨平台后部。关节镜下软骨损伤与骨挫伤并非一一对应的关系。     

膝关节外伤性骨软骨骨折的X线和MRI表现

目的 探讨膝关节骨软骨骨折的X线和MRI表现.方法 12例膝关节外伤患者分别行X线平片及MR检查，回顾分析其表现并与关节镜及手术对照.结果 12例患者MRI诊断13处膝关节骨软骨骨折，7处位于股骨外髁，6处位于髌骨，同时可见9块游离骨折片，MRI能清楚地显示骨软骨骨折的确切部位、大小、程度，而且能分辨出骨折块的软骨成分及软骨下骨质成分，T2WI、短时反转恢复(STIR)、快速梯度回波(FFE)T2WI序列三者结合显示骨软骨骨折最为清楚。X线检查可见5例关节内游离骨块，不能明确来源。结论 MRI能准确显示并诊断膝关节外伤后骨软骨骨折，提高临床诊断并指导关节镜及手术治疗。X线为膝关节骨软骨骨折的最基本手段，明确诊断应结合MR检查。     

Osteonecrosis of the knee after arthroscopic surgery: diagnosis with MR imaging

Spontaneous osteonecrosis about the knee typically is a disease of the elderly characterized by an acute onset of pain. The exact cause of this condition has long been debated, although a causative relationship between meniscal tears and spontaneous osteonecrosis about the knee has been postulated. Seven patients with knee pain, meniscal tears, and chondromalacia without initial evidence of osteonecrosis at magnetic resonance (MR) imaging underwent arthroscopic surgery with meniscal recontouring or repair and cartilage shaving. These patients returned within 2-14 months with recurrent pain in the treated knee. MR imaging then demonstrated abnormalities consistent with osteonecrosis. Osteonecrosis of the femoral condyle or tibial plateau may be a late sequela of meniscal injury in association with chondromalacia and arthroscopic surgery. This diagnosis should be suspected in patients with recurrent knee pain after arthroscopic repair of meniscal tears. The precise relationship of this pattern of osteonecrosis to that previously described as spontaneous requires further investigation.     

Indirect signs of anterior cruciate ligament injury on SPET: comparison with MRI and arthroscopy

Indirect signs of anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI) include bony contusions in the lateral femoral condyle and the posterior portion of the lateral tibial plateau. This study was undertaken to assess the value of single photon emission tomography (SPET) in the diagnosis of ACL injury by examining the uptake pattern in the distal femur and the proximal tibia. Thirty-five patients were examined using SPET, MRI and arthroscopy. Seventeen patients were found to have ACL tears on arthroscopy. The duration of symptoms was 4 days to 10 years (mean 26.4 months). MRI and SPET images were analysed retrospectively without information from arthroscopic examination. Radionuclide uptake in the lateral femoral condyle and the posterior lateral tibial plateau was considered an indirect sign of ACL injury on SPET. We evaluated the diagnostic value of indirect signs of ACL injury obtained on SPET by comparing these findings with arthroscopic and MRI results. Fifteen of 17 patients with ACL injury showed indirect signs on SPET. The sensitivity, specificity, positive predictive value and negative predictive value for indirect signs of ACL injury were 88%, 56%, 65% and 83% on SPET and 59%, 94%, 91% and 71% on MRI, respectively. However, despite the higher sensitivity of indirect signs on SPET than on MRI, the overall diagnostic value of MRI is better than that of SPET. In the clinical setting, indirect signs of ACL injury may be of value in interpreting incidental findings on SPET.     

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.     

Lateral femoral condylar shearing fractures

Lateral femoral condylar shearing fractures occur as the aftermath of acute patellar dislocation. The fracture fragment may be larger than originally appreciated on plain films. Diagnosis depends on identifying the fracture fragment somewhere within the knee joint, and the "donor site" on the lateral femoral condyle. Therefore, MRI or arthroscopy should be performed to identify the true size of the fracture fragment. The larger of these fragments may require surgical intervention with fixing of the fracture fragment onto the lateral condyle with screws. We present the radiographic and clinical findings in seven patients. Electronic Publication