Gender-related differences in concomitant articular injuries after acute lateral patellar dislocation

ObjectivesTo explore the gender differences in the concomitant articular injuries after acute lateral patellar dislocation (LPD).MethodsMagnetic resonance images were prospectively analyzed in 166 patients after an acute LPD. Concomitant articular injuries included bone contusion, medial patellofemoral ligament (MPFL) injury, articular cartilage lesion, and vastus medialis obliquus (VMO) lesion. Statistical analyses were performed between the patient's gender and the incidence of concomitant articular injuries in adolescent and adult subgroups.ResultsThe incidence of partial and complete MPFL tear in adolescent males and females were (45%, 50%) and (63.2%, 29.8%), respectively. Compared with adolescent females, adolescent males showed higher incidence of complete MPFL tear (P = 0.049). The incidence of articular cartilage lesion of patella in adolescent males and females were 40% and 21.1%, respectively. Compared with adolescent females, adolescent males showed higher incidence of articular cartilage lesion of the patella (P = 0.043). No correlations were identified in other injuries in the adolescent group. The incidence of partial and complete MPFL tear in adult males and females were (34.4%, 65.6%) and (56.8%, 37.8%), respectively. Compared with adult females, adult males showed higher incidence of complete MPFL tear (P = 0.036). The incidence of articular cartilage lesion of patella in adult males and females were 56.3% and 32.4%, respectively. Compared with adult females, adult males showed higher incidence of articular cartilage lesion of patella (P = 0.047). The incidence of VMO injury in adult males and females were 59.4% and 35.1%, respectively. Compared with adult females, adult males showed higher incidence of VMO injury (P = 0.044). No correlations were identified in other injuries in the adult group.ConclusionsCompared with females, males predispose to complete MPFL tear and articular cartilage lesion of patella after acute LPD. Compared with female adults, male adults predispose to VMO injury.     

比较前交叉韧带撕裂与髌骨外侧脱位患者髌股关节解剖学参数异常检出率

目的 对比前交叉韧带（ACL）撕裂与髌骨外侧脱位（LPD）患者之间，股骨滑车发育不良、髌骨高位、胫骨结节-股骨滑车沟（TT-TG）间距过宽检出率的差异。方法 回顾性分析79例ACL撕裂患者（ACL撕裂组）、46例LPD患者（LPD组）及100例膝关节未见明显异常者（对照组）的膝关节MRI，对比3组间股骨滑车发育不良、髌骨高位（Insall-Salvati指数>1.2）及TT-TG间距过宽（TT-TG间距>15 mm为过宽）检出率的差异。结果 ACL撕裂组中，股骨滑车发育不良18例（18/79，22.78%），髌骨高位12例（12/79，15.19%），TT-TG间距过宽10例（10/79，12.66%）；LPD组中，股骨滑车发育不良26例（26/46，56.52%），髌骨高位21例（21/46，45.65%），TT-TG间距过宽13例（13/46，28.26%）；对照组股骨滑车发育不良9例（9/100，9.00%），髌骨高位6例（6/100，6.00%），TT-TG间距过宽5例（5/100，5.00%）。3组间股骨滑车发育不良、髌骨高位和TT-TG间距过宽检出率差异均有统计学意义（P均<0.01）；LPD组股骨滑车发育不良、髌骨高位检出率均高于对照组及ACL撕裂组（P均<0.05），TT-TG间距过宽检出率高于对照组（P<0.05）；ACL撕裂组TT-TG间距过宽检出率与LPD组及对照组差异均无统计学意义（P均>0.05）。结论 股骨滑车发育不良、髌骨高位及TT-TG间距过宽在ACL撕裂与LPD患者中的检出率均较高；前二者在LPD中尤为显著。     

Chondral fracture of the lateral trochlea of the femur occurring in an adolescent: mechanism of injury

The trochlea of the femur is a very unusual site for chondral fracture. Little is known of the mechanism of injuries confined to the articular cartilage of the trochlea of the femur. A very unusual case of chondral fracture of the lateral trochlea of the femur occurring in an adolescent is reported here. The mechanism by which this injury occurred could be evaluated in this patient. The cartilage on the convex surface of the lateral trochlea was likely avulsed proximally by shear force of the patella during rapid extension of the weight-bearing knee from a flexed position. From a viewpoint of mechanism, this injury differs from the more usual osteochondral or chondral fractures of the weight bearing area of the femoral condyle, which are usually accompanied by twisting forces.     

Morphological analysis of the femoral trochlea in patients with recurrent dislocation of the patella using three-dimensional computer models

We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models. There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage. The mean extent of convexity was 24.9 degrees sd 6.7 degrees for patients and 11.9 degrees sd 3.6 degrees for the control group (p < 0.001). The mean height of the articular cartilage was 91.3 degrees sd 8.3 degrees for the patients and 83.3 degrees sd 7.7 degrees for the control group (p = 0.03), suggesting a wider convex trochlea in the patients with recurrent dislocation of the patella caused by the proximally-extended convex area. The lateral border of the articular cartilage of the trochlea in the patients was more laterally located than in the control group. Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects.     

Chondral and osteochondral injuries associated with acute patellar dislocation

Purpose: The purpose of this study was to evaluate the frequency and precise pathology of articular cartilage injuries after acute patellar dislocation. Type of Study: Case series. Methods: In 39 consecutive knees with initial lateral patellar dislocation, the articular cartilage injuries were examined using arthroscopy or macroscopic observation. Results: Thirty-seven knees (95%) had articular cartilage injuries of the patellofemoral joint and 2 knees (5%) had no cartilage injury. In all 37 knees (95%), articular cartilage injuries were observed in the patella. The appearances were categorized into 3 groups: cracks alone (9 knees), cartilage defect caused by osteochondral or chondral fracture (7 knees), and cartilage defects caused by osteochondral or chondral fracture associated with cracks (21 knees). The main site of osteochondral fracture was the medial facet, and the main site of cracks was the central dome. Twelve knees (31%) had cartilage injury of the lateral femoral condyle. Conclusions: From this study, articular cartilage injuries, especially of the patella, seem to be common occurrences after acute patellar dislocation. Chondral and osteochondral injuries of the patella were classified into 3 groups.     

Tibial Tubercle-Trochlear Groove Distance Influences Patellar Tilt After Total Knee Arthroplasty

BackgroundTibial tubercle-trochlear groove (TT-TG) distance is associated with a greater risk of recurrent patellar dislocation in young, active patients. However, the effect of TT-TG distance after total knee arthroplasty (TKA) has not been investigated. The purpose is to analyze the effect of TT-TG distance and component rotation on patellar tilt and patellar shift after TKA.MethodsAfter TKA, axial computed tomography scans and axial radiograph were taken in 115 consecutive knees. TT-TG distance was measured between the most anterior point of the tibial tuberosity and the deepest point of the femoral component relative to a line connecting the anterior condyles. Femoral and tibial component rotation was measured relative to the femoral and tibial rotational axis, respectively. Pearson correlation coefficients were calculated.ResultsTT-TG distance had a significant correlation with patellar tilt in extension (R = 0.220, P = .018), patellar tilt in flexion (R = 0.438, P < .001), and patellar shift (R = 0.330, P < .001). Tibial component rotation had a significant correlation with patellar tilt in flexion (R = −0.251, P = .007) and patellar shift (R = −0.360, P < .001). Femoral component rotation had no significant correlations. Tibial component rotation had a significant correlation with TT-TG distance (R = −0.573, P < .001), whereas femoral component rotation had no correlation (P = .192).ConclusionTT-TG distance had a significant correlation with patellar tilt and patellar shift. Surgeons need to understand the factors affecting TT-TG distance and to pay attention to avoiding excessive TT-TG distance after TKA.     

Threshold for lateral meniscal body extrusion on MRI in middle-aged and elderly patients with symptomatic knee osteoarthritis

PurposeTo determine the MRI-based threshold of lateral meniscal body extrusion (LMBE) that are associated with meniscal damage, cartilage damage and radiological knee osteoarthritis (OA).Materials and methodsA total of 142 patients (59 men and 83 women) with a mean age of 57.2 ± 7.9 (SD) years (range: 41–77 years) with symptomatic knee OA were included. Radiological assessment was performed using the Kellgren-Lawrence scoring system. Meniscus and cartilage damage were assessed using the whole-organ magnetic resonance imaging score. Meniscal extrusion was quantified on coronal sections of intermediate-weighted MRI sequences. Differences between medial and lateral compartments in meniscal extrusion and incidence of tibiofemoral OA-related structural changes were assessed using Wilcoxon signed rank test and Bowker test. Receiver operating characteristic curves and Youden index were used for determining thresholds for meniscal extrusion.ResultsA total of 142 knees were assessed. Meniscal body extrusion distances between medial and lateral compartments were significantly different in the entire sample, and in subjects with and without radiological knee OA (P < 0.05 for all). The incidence of structural changes between medial and lateral compartments were significantly different (P = 0.003 for meniscal damage; P = 0.001 for femoral cartilage damage). Three mm and 2 mm were determined to be the optimal thresholds for medial and lateral meniscal body extrusion, respectively.ConclusionMedial and lateral meniscal body extrusion were associated with the incidence of OA-related knee structural changes in symptomatic patients with knee OA. A threshold of 2 mm for LMBE with respect to meniscal damage, cartilage damage and radiological knee OA was determined.     

Decreasing Thickness of Partial Lateral Trochlear Cartilage in Patients with Patellar Instability

ObjectiveTo explore morphological characteristics of patellofemoral joint surface of patients with patellar instability by adopting the MRI‐based method.MethodsA retrospective analysis was performed from March 2016 to January 2020 to assess morphological characteristics of the patellofemoral joint surface by Magnetic Resonance Imaging (MRI) scanning knees of 30 patients (24 females, six males) with patellar instability and trochlear dysplasia and knees of 30 subjects from a randomly selected control group (25 females, five males). The control group was matched as per age and sex. All participants had undergone MRI scans in the supine position and keep knees in or near full extension. Six parts were measured in total, including thickness of trochlear cartilage, thickness of patella cartilage, cartilaginous sulcus angle, cartilaginous Wiberg angle, contact range and frequency and distributions of the mean difference measurement of the femoral trochlea, to evaluate the difference of trochlear and patellar morphology between the patient group and the control group. The threshold for statistical significance was set at P < 0.05.ResultsThere were significant differences in four values between the two groups (P < 0.05). The cartilage thickness two‐third along the lateral condyle in the patient group was significantly lower than that in the control group (LCT2,1.80 ± 0.37 vs 2.06 ± 0.52, 1.92 ± 0.36 vs 2.17 ± 0.50), but there was no significant difference in other sites. There was no significant difference in patella thickness between the patient group and the control group. The cartilaginous sulcus angle in the patient group was larger than that in the control group (157.90 ± 6.64 vs 142.23 ± 3.95, P < 0.001), but there was no significant difference in cartilaginous Wiberg angle. The patient group had a larger initial contact ratio (59.47 ± 6.13 vs 46.50 ± 3.67, P < 0.001), and a smaller contact range (16.55 ± 4.14 vs 27.55 ± 4.09, P < 0.001). The deepest part of the intercondylar suclus appears more often in the lateral of the deepest part of the osseous concavity of the femoral trochlea. Among the patient group, 18 cases (60%) were found with the deepest part of the intercondylar suclus lateral to the deepest point of the osseous concavity of the femoral trochlea while among the control group only 4 cases (13.33%) were found. The distribution of trochlear dysplasia of Dejour grades was type B (n = 22), type C (n = 5), and type D (n = 3).ConclusionThickness of partial lateral trochlear cartilage decreases in patients with patellar instability and the trochlear cartilage develops abnormal morphological characteristics. Moreover, it also suggests that MRI can be used to further present the morphology of cartilage for the convenience of surgical planning.     

Articular cartilage lesions in the symptomatic anterior cruciate ligament-deficient knee

Purpose: The goal of the study was to report the prevalence of the lesions of the articular cartilage of the femoral condyles and tibial plateau in patients with a symptomatic anterior cruciate ligament (ACL)-deficient knee undergoing day-case arthroscopy. Type of Study: Case series study. Methods: We studied 378 skeletally mature patients (average age, 27.3 years; range, 16–50 years; 282 men and 84 women), part of a sample of 1,978 patients undergoing a primary knee arthroscopy between January 1986 and August 1993. The articular cartilage lesions were classified according to Outerbridge by a single observer. We assessed the relationship between time of injury and articular cartilage lesions and between meniscal lesions and articular cartilage lesions. Results: A complete ACL tear was found in all 378 knees. Of these, 157 showed at least one lesion of the articular cartilage. The medial femoral condyle (MFC) showed the highest frequency of articular cartilage lesions, especially in the weight-bearing portion. Patients with a bucket-handle tear of the medial meniscus had greater degeneration of the MFC than those with other meniscal tears. A meniscal tear was associated with a greater degree of articular damage. The second most common lesion was a combined lesion of the medial and lateral compartments, followed by isolated lateral compartment lesion. A time-dependent pattern of development of articular cartilage lesions was identified. Conclusions: In patients with more advanced degenerative changes, the time from injury to arthroscopy was significantly longer than in patients with lesser articular surface abnormalities, and the presence of a meniscal tear was associated with a greater degree of articular cartilage damage. Patients with a symptomatic ACL-deficient knee and an associated tear of the medial meniscus are at high risk of having a lesion of the articular surface of the weight bearing area of the knee.     

Sonography on injury of the medial patellofemoral ligament after acute traumatic lateral patellar dislocation: Injury patterns and correlation analysis with injury of articular cartilage of the inferomedial patella

Objective

The purpose of this study was to investigate the accuracy of high-frequency ultrasonography in the diagnosis of injuries of medial patellofemoral ligaments (MPFLs), analyse the characteristics of MPFL injury and correlations between injury of the MPFL and articular cartilage of the inferomedial patella in patients with acute traumatic lateral patellar dislocation.

Methods

High-frequency sonographic images of 49 patients with acute traumatic lateral patellar dislocations treated surgically were reviewed. The χ² tests were performed for statistical analysis.

Results

Twenty-eight cases of complete MPFL tear and 21 cases of partial MPFL tear were identified in operation, with 27 cases of MPFL tear located at their femoral attachment, 21 cases of tear at the patellar attachment and one case of midsubstance tear. The diagnostic accuracy of sonography regarding partial MPFL tear and complete MPFL tear was 89.8% and 89.8%. Among the patients with MPFL tear at the patellar attachment, eight and six cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, in contrast to nine and six cases in patients with MPFL tear at the femoral attachment, respectively. There was no significant difference between the two locations described above regarding the prevalence rates of chondral or osteochondral lesions of the inferomedial patella (P = 0.732, P = 0.614). Among the patients with complete MPFL tear, 12 and 10 cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, while six and two cases were concomitant with partial MPFL tear. There was no significant difference between the two types of injuries discussed above on the prevalence rates of chondral lesions of the inferomedial patella (P = 0.305), but the prevalence rate of osteochondral lesions between the two types of injuries discussed above was statistically different (P = 0.035).

Conclusions

The MPFL is most easily injured at the femoral attachment, secondly at the patellar attachment. High-frequency ultrasonography is an accurate method in the diagnosis of an MPFL tear. There are neither significant differences on the prevalence rates of chondral or osteochondral lesions of the inferomedial patella between locations of MPFL injuries, nor significant difference on the prevalence rates of chondral lesions between MPFL injury types; but the complete MPFL tear is more often concomitant with inferomedial patellar osteochondral lesions than the partial MPFL tear.     

High resolution T21 mapping in assessment of knee articular cartilage on 3T MRI

ObjectiveTo evaluate the spectrum of T21 values in healthy cartilage of young asymptomatic adults on high resolution 3T MRI.MethodsA total of 50 asymptomatic adult volunteers with age ranging from 18 to 35 years were enrolled for the study with the purpose of assessing T21 values in healthy cartilage without any degenerative changes. The articular cartilage was assessed on two sections, one each through the medial and lateral compartments. The cartilage was segmented into 8 regions through the tibio-femoral and patella-femoral joints. Further post processing was done using multiple ROI placement to delineate ROI areas for calculation of full thickness and zonal (superficial and deep) T21 values. Thus, a total of 1200 ROI areas (50 volunteers, 8 segments, and 3 areas for each segment) were assessed.ResultsThe results revealed a superior bulk T21 value of 29.2 ± 3.6 ms from the posterior medial femoral cartilage and 26.1 ± 3.1 ms from the patellar region. Intermediate values were obtained from posterior lateral femoral cartilage, central femoral cartilage, and trochlea. The tibial plateau cartilage had the lowest values – 19.6 ± 2.6 ms for the medial tibial plateau and 20.6 ± 2.8 ms for lateral tibial plateau. The study demonstrated substantial regional physiological variation existing in the T21 values across various regions of the knee joint, which could be attributed to varying amounts of shearing forces across the joint. No significant differences were noted in bulk T21 values between the two genders, with only the trochlear segment revealing significantly increased values in males (p = 0.007). All the cartilage segments revealed significantly increased T21 values in the superficial zone as compared to the deep zone.ConclusionThere is a significant regional difference in the bulk T21 values of articular cartilage in a normal physiological state across various joint segments. A zonal gradient with increasing values from the deep to the superficial zone also exists. These findings can prove invaluable in assessing changes in T21 values occurring in diseased/degenerative cartilage.     

Acute traumatic and sports-related osteochondral injury of the pediatric knee

Adolescents are predisposed to osteochondral (OC) injuries in the knee. The medial facet of the patella, the femoral trochlea, and the lateral femoral condyle are the most common sites of injury. Most of these injuries are classically traumatic but noncontact injuries. Surgery is warranted in most cases of OC fracture. Depending on size, condition, and location of the lesion, options include OC fragment reduction and internal fixation or excision and cartilage resurfacing. Understanding of how to diagnose and treat OC fractures will help optimize outcomes.     

Die Transplantation autogener Knorpelzellen in Gelenkflächendefekte des Kniegelenks

Objective Repair of articular cartilage defects of knee to restore a pain-free joint function. Indications Full-thickness chondral or osteochondral posttraumatic lesions and osteochondritis dissecans defects that have not been successfully repaired with methods such as debridement, drilling, and microfracturing. Contraindications Osteoarthritis. Rheumatoid arthritis. Sugical Technique During arthroscopy, the cartilage lesion is evaluated, and cartilage slices weighing 200–300 mg are harvested from the upper medial femoral condyle, a minor load bearing area. The chondrocytes are isolated enzymatically and grown in culture to increase the cell number during approximately 2 weeks. During the second operation, an arthrotomy is performed through a medial or lateral parapatellar approach. The defect is carefully debrided. A periosteal patch is obtained from proximal tibia, placed over the defect and sutured to the surrounding cartilage. The suture line is sealed with fibrin glue, and the chondrocytes are injected into the defect under the patch. Results Recently, Peterson has presented results in 213 patients with a follow-up between 2–10 years. He reported good to excellent results in 90% of 57 patients with single femoral condyle lesions, in 84% of 32 patients with osteochondritis dissecans and in 74% of 27 patients with femoral condyle lesions in combination with anterior cruciate ligament reconstruction. In 32 patients the patella was grafted and 22 improved, in twelve patients the trochlea was grafted and seven improved, and in 53 patients multiple lesions were grafted and 42 improved. Second-look arthroscopies were performed in 46 patients, 26 of them were biopsied; the transplanted tissues showed a hyaline-like appearance in 21 patients (80%).     

Improved repair of chondral and osteochondral defects in the ovine trochlea compared with the medial condyle

Associations between topographic location and articular cartilage repair in preclinical animal models are unknown. Based on clinical investigations, we hypothesized that lesions in the ovine femoral condyle repair better than in the trochlea. Full‐thickness chondral and osteochondral defects were simultaneously established in the weightbearing area of the medial femoral condyle and the lateral trochlear facet in sheep, with chondral defects subjected to subchondral drilling. After 6 months in vivo, cartilage repair and osteoarthritis development was evaluated by macroscopic, histological, immunohistochemical, and biochemical analyses. Macroscopic and histological articular cartilage repair and type‐II collagen immunoreactivity were better in the femoral trochlea, regardless of the defect type. Location‐independently, osteochondral defects induced more osteoarthritic degeneration of the adjacent cartilage than drilled chondral lesions. DNA and proteoglycan contents of chondral defects were higher in the condyle, reflecting physiological topographical differences. The results indicate that topographic location dictates the structural patterns and biochemical composition of the repair tissue in sheep. These findings suggest that repair of cartilage defects at different anatomical sites of the ovine stifle joint needs to be assessed independently and that the sheep trochlea exhibits cartilage repair patterns reflective of the human medial femoral condyle. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1772–1779, 2013     

Flexion Space Balancing Through Component Positioning and Its Relationship to Traditional Anatomic Rotational Landmarks in Robotic Total Knee Arthroplasty

BackgroundThe use of the femoral component position to balance the flexion space and its relationship to the transepicondylar axis (TEA) and posterior condylar angle (PCA) has not been thoroughly evaluated.MethodsA total of 233 patients undergoing robotic arm–assisted total knee arthroplasty were evaluated. Native TEA and PCA were established on preoperative computed tomography scans. Femoral component rotation was set in the axial plane to match the native trochlea and native medial femoral condyle to set the flexion gap. Knee flexion space gaps and component position were recorded. The relationship of the femoral component to the native TEA, PCA, and preoperative radiographic landmarks was evaluated.ResultsThe intraoperative measured medial flexion space gap did not significantly correlate with the relationship of the femoral component to the PCA or TEA in varus or valgus knees. In varus knees, the preoperative mechanical axis alignment had a positive relationship to femoral component position when compared to the PCA (P = .04) and TEA (P = .002). In valgus knees, there was a positive correlation between the preoperative lateral distal femoral angle and component position when compared to the PCA (P = .04) only.ConclusionIntraoperative measured flexion space balance through femoral component positioning did not correlate with its relationship to the native TEA or PCA. In varus knees, the preoperative mechanical axis alignment correlated with an increase in femoral component external rotation to the TEA and PCA. In valgus knees, the severity of preoperative lateral distal femoral angle correlated with the rotational relationship of the femoral component to the PCA only.     

Functional properties of native and tissue‐engineered cartilage toward understanding the pathogenesis of chondral lesions at the knee: A bovine cadaveric study

Chondral lesions frequently occur in different topographic locations of the knee. This study evaluated the functional properties among the articulating surfaces of the tibiofemoral and patellofemoral joints, and whether neo‐cartilage engineered using chondrocytes from different knee locations would reflect these differences. The biomechanical properties of bovine cartilage isolated from eight locations within the tibiofemoral (medial and lateral condyle, medial and lateral tibial plateau) and patellofemoral joints (medial and lateral trochlea, medial and lateral patella) were examined. Tensile Young's moduli (tensile moduli) and aggregate moduli of the medial condyle were lower than those of the medial tibial plateau (6.11 ± 0.89 MPa vs. 7.19 ± 1.05 MPa, p = 0.04 and 354.4 ± 38.3 kPa vs. 419.4 ± 31.3 kPa, p = 0.002, respectively). Patella tensile and compressive moduli were lower than the trochlea (4.79 ± 2.01 MPa vs. 6.91 ± 2.46 MPa, p = 0.01 and 337.4 ± 37.2 kPa vs. 389.1 ± 38.3 kPa, p = 0.0005, respectively). Furthermore, chondrocytes from the above locations were used to engineer neo‐cartilage, and its respective properties were evaluated. In neo‐cartilage, medial condyle tensile and aggregate moduli were lower than in the medial tibial plateau (0.96 ± 0.23 MPa vs. 1.31 ± 0.31 MPa, p = 0.02, and 115.8 ± 26.0 kPa vs. 160.8 ± 18.8 kPa, p = 0.001, respectively). Compared to trochlear chondrocytes, neo‐cartilage formed from patellar chondrocytes exhibited lower tensile and compressive moduli (1.16 ± 0.27 MPa vs. 0.74 ± 0.25 MPa, p < 0.001, and 109.1 ± 24.0 kPa vs. 82.5 ± 18.1 kPa, p < 0.001). A significant degree of disparity in biomechanical properties of the opposing articular surfaces was detected; the medial condyle and patella exhibited inferior properties compared to the opposing medial tibial plateau and trochlea, respectively. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2452–2464, 2017.

     

Articular Cartilage Repair in the Knee Joint with Autologous Chondrocytes and Periosteal Graft

Objective Repair of articular cartilage defects of knee to restore a pain-free joint function. Indications Full-thickness chondral or osteochondral posttraumatic lesions and osteochondritis dissecans defects that have not been successfully repaired with methods such as debridement, drilling, and microfracturing. Contraindications Osteoarthritis. Rheumatoid arthritis. Surgical Technique During arthroscopy, the cartilage lesion is evaluated, and cartilage slices weighing 200-300 mg are harvested from the upper medial femoral condyle, a minor load bearing area. The chondrocytes are isolated enzymatically and grown in culture to increase the cell number during approximately 2 weeks. During the second operation, an arthrotomy is performed through a medial or lateral parapatellar approach. The defect is carefully debrided. A periosteal patch is obtained from proximal tibia, placed over the defect and sutured to the surrounding cartilage. The suture line is sealed with fibrin glue, and the chondrocytes are injected into the defect under the patch. Results Recently, Peterson has presented results in 213 patients with a follow-up between 2-10 years. He reported good to excellent results in 90% of 57 patients with single femoral condyle lesions, in 84% of 32 patients with osteochondritis dissecans and in 74% of 27 patients with femoral condyle lesions in combination with anterior cruciate ligament reconstruction. In 32 patients the patella was grafted and 22 improved, in twelve patients the trochlea was grafted and seven improved. and in 53 patients multiple lesions were grafted and 42 improved. Second-look arthroscopies were performed in 46 patients, 26 of them were biopsied; the transplanted tissues showed a hyaline-like appearance in 21 patients (80%).     

The lateral condyle index: a new index for assessing the length of the lateral articular trochlea as predisposing factor for patellar instability

The central trochlea has been considered as the major location of dysplasia. The purpose of this study was to investigate the influence of the lateral trochlea on patellar stability and to establish a new method for measuring the lateral trochlea on sagittal magnetic resonance (MR) images. Twenty-eight knees of 23 patients suffering from lateral patellar subluxation (12 knees with radiological signs of central trochlear dysplasia) and of 46 patients without patellofemoral complaints (without central trochlear dysplasia) were analysed. The lateral condyle index was designed to measure the lateral trochlea by comparing the anterior cartilaginous trochlea (a) and the posterior aspect (p) [(a:p)× 100]. The lateral condyle index showed high interrater reliability (r = .94) and was significantly (p < 0.001) lower in symptomatic patients (86%) than in the control group (93%). These results show high clinical relevance of the lateral trochlea as another factor for patellar instability.     

膝关节软骨人体标本解剖与磁共振成像的比较研究

目的 探讨膝关节尸体标本解剖与磁共振成像(MRI)三维序列-扰相梯度回波序列(3D-FS-SPGR)测量关节软骨厚度的差异,并分析软骨组织主要成分在关节软骨不同位置的差异.方法选用国人青壮年中等身材、无明显关节病变的成年男性尸体膝关节标本2具,首先进行3D-FS-SPGR序列矢状位扫描.复冻后按解剖部位进行矢状位解剖,分别对股骨及胫骨内、外髁负重区前、后面及髌骨面软骨厚度进行测量.关节软骨石蜡切片进行维多利亚蓝-丽春红复合染色并观察.结果 软骨尸体标本解剖与3D-FS-SPGR序列测得的膝关节软骨厚度:股骨外侧髁前负重面平均分别为2.25、2.25 mm,股骨外侧髁后负重面平均分别为2.70、2.75 mm,胫骨外侧髁前负重面平均分别为2.00、2.10 mm;胫骨外侧髁后负重而平均分别为2.35、2.25 mm,股骨内侧髁前负重面平均分别为2.20、2.20 mm,股骨内侧髁后负重面平均分别为2.15、2.30 mm,胫骨内侧髁前负重面半均分别为2.20、2.45mm,胫骨内侧髁后负重面平均分别为2.70、2.95 mm,髌骨面软骨平均分别为3.08、3.15 mm.软骨组织学染色显示:关节软骨表层胶原纤维含量相对较多,软骨细胞及其周围基质相对较少;在关节软骨深层,胶原纤维含量相对较少,而软骨及软骨周围基质相对较多.结论 3D-FS-SPGR序列能够相对真实地反映关节软骨的形态及厚度.胶原纤维主要集中在软骨表层,其分布与软骨的功能相一致.

Abstract：

Objective To compare corpse sampling and MR imaging with 3D-FS-SPGR sequences in measurement of the articular cartilage thickness and to investigate knee cartilage topography. Methods Two fresh specimens of the knee joint were obtained from 2 normal young adult male corpses of medium stature. MR1 scanning was carried on the 2 specimens in sagittal 3D-FS-SPGR MR sequences. After defrosted,the knee specimens were dissected longitudinally, and the cartilage thicknesses were measured at different locations of the knee joint. Paraffin sections of the knee cartilage were observed following compound staining with victoria blue and ponceau red. Results The average cartilage thicknesses measured by dissection and MR imaging sequence were respectively: 2. 25 mm and 2. 25 mm at the anterior weight-loading surface of the femoral lateral condyle, 2. 70 mm and 2. 75 mm at the posterior weight-loading surface of the femoral lateral condyle, 2. 00 mm and 2. 10 mm at the anterior weight-loading surface of the tibial lateral condyle,2. 35 mm and 2. 25 mm at the posterior weight-loading surface of the tibial lateral condyle, 2. 20 mm and 2. 20mm at the anterior weight-loading surface of the femoral medial condyle, 2. 15 mm and 2. 30 mm al the posterior weight-loading surface of the femoral medial condyle, 2. 20 mm and 2.45 mm at the anterior weight-loading surface of the tibial medial condyle, 2. 70 mm and 2. 95 mm at the posterior weight-loading surface of the tibial medial condyle and 3. 08 mm and 3. 15 mm at patella cartilage surface. Collagen fibers were rich at the periphery of the articular cartilage with sparse chondrocytes and matrixes, while the opposite was observed at the center of the articular cartilage. Conclusions MR imaging with 3D-FS-SPGR sequences can display the actual knee cartilage topography. Collagen fibers mainly concentrate at the periphery of the articular cartilage, which accounts for the function of the articular cartilage.     

Editorial Commentary: Knee Lateral Femoral Osteochondral Allografts Are Not Recommended for Medial Femoral Condylar Defects: If the Shoe Doesn’t Fit,Don’t Wear It!

Treatment of large articular cartilage defects of the knee is challenging, particularly in young, high-demand patients. Osteochondral allograft (OCA) transplantation is a viable treatment option, providing fully mature articular cartilage during a single operation while avoiding donor site morbidity. Indications are symptomatic, full-thickness articular cartilage defects >3 cm². Contraindications include a “kissing” lesion of the corresponding articular cartilage surface, uncorrected ligamentous instability, malalignment, peripheral osteophytes, joint-space narrowing, or absence of >50% of the meniscus in the affected compartment. Matching for size and contour is crucial; therefore, we use medial femoral condyle (MFC) allografts for MFC lesions and lateral femoral condyle (LFC) allografts for LFC lesions, and do not recommend LFC grafts for the MFC. Survival rates are 78.7% and 72.8% at 10 and 15 years, respectively.