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Purpose: In total knee arthroplasty (TKA), various landmarks are generally used to ensure correct osteotomy. In this study, we examined whether the tibialis anterior tendon (TAT) or the extensor hallucis longus tendon (EHLT) could be used as a landmark of the center of the ankle joint in patients with knee osteoarthrosis (OA), using magnetic resonance imaging (MRI)., Methods: The subjects were 61 patients with OA in 79 knees (males: 8 with 9 knees and females: 53 with 70 knees). With the ankle joint secured in the intermediate position, MRI from the knee joint to the ankle joint was performed in the same foot position. We prepared individual lines connecting the center of the ankle joint with the TAT or EHLT to measure the angle difference (ΔA) from Akagi's line in the knee joint. We analyzed whether the ΔA might be affected by deformity of the knee joint or foot region, and tibial torsion., Results: At the ankle joint level, the ΔA of EHLT was the smallest, with an average of 1.6 ± 3.4°. The ΔA for the femorotibial angle, hallux valgus angle, and varus-valgus angle showed no correlations with deformity of the knee joint and foot region, or tibial torsion., Conclusions: MRI findings showed that EHLT would be useful as a landmark of the ankle joint center in extramedullary tibial osteotomy in TKA for medial knee OA. It was also clarified that the landmark would not be affected by severe deformity of the knee joint, deformity of the foot region, or external torsion of the tibia.

Purpose: Recurrent patellar dislocation is currently treated with anatomical reconstruction of the medial patellofemoral ligament (MPFL), and favourable postoperative outcomes have been reported. However, it is uncertain if healthy MPFL function is restored by anatomical reconstruction. The hypothesis in this study was that stabilization of the patella following MPFL reconstruction would be improved compared with that before surgery, but that function of the grafted tendon would differ from that of a healthy MPFL. The objective was to analyse the length change patterns of the MPFL before surgery and the grafted tendon after surgery in patients with recurrent patellar dislocation treated with anatomical MPFL reconstruction., Methods: The subjects were 12 patients (13 knees) in whom recurrent patellar dislocation was treated with anatomical MPFL reconstruction. The length change patterns of the MPFL and reconstructed ligament were analysed at extension and flexion of the knee joint using open MRI., Results: The postoperative grafted tendon length was significantly shorter than that of the preoperative MPFL at knee extension, and significantly longer at 90° and 120° of knee flexion. The postoperative length of the grafted tendon only changed slightly from 0° to 30° of knee flexion, and then significantly decreased at flexion of 30° or more. The morphology of the grafted tendon was linear until 60° knee flexion, but became convex toward the extraarticular side at flexion of 90° or more., Conclusion: The grafted tendon length at knee extension was shorter than that of the preoperative MPFL, but there was no significant difference at 30° flexion. These findings suggest that the effect of damping of the patella with a grafted tendon after MPFL reconstruction may differ from that in a healthy knee. In addition, the morphology at 60° knee flexion was improved to linear after surgery, suggesting that ligament morphology at this flexion was normalized by MPFL reconstruction., Level of Evidence: III.

Purpose: To compare the histologic and biomechanical effects of 3 different footprint preparations for repair of tendon-to-bone insertions and to assess the behavior of bone marrow-derived cells in each method of insertion repair., Methods: We randomized 81 male Sprague-Dawley rats and green fluorescent protein-bone marrow chimeric rats into 3 groups. In group A, we performed rotator cuff repair after separating the supraspinatus tendon from the greater tuberosity and removing the residual tendon tissue. In group B, we also drilled 3 holes into the footprint. The native fibrocartilage was preserved in groups A and B. In group C, we excavated the footprint until the cancellous bone was exposed. Histologic repair of the tendon-to-bone insertion, behavior of the bone marrow-derived cells, and ultimate force to failure were examined postoperatively., Results: The areas of metachromasia in groups A, B, and C were 0.033 ± 0.019, 0.089 ± 0.022, and 0.002 ± 0.001 mm 2 /mm 2 , respectively, at 4 weeks and 0.029 ± 0.022, 0.090 ± 0.039, and 0.003 ± 0.001 mm 2 /mm 2 , respectively, at 8 weeks. At 4 and 8 weeks postoperatively, significantly higher cartilage matrix production was observed in group B than in group C (4 weeks, P = .002; 8 weeks, P < .001). In green fluorescent protein-bone marrow chimeric rats in group B, bone marrow-derived chondrogenic cells infiltrated the fibrocartilage layer. Ultimate force to failure was significantly higher in group B (19.7 ± 3.4 N) than in group C (16.7 ± 2.0 N) at 8 weeks (P = .031)., Conclusions: Drilling into the footprint and preserving the fibrocartilage improved the quality of repair tissue and biomechanical strength at the tendon-to-bone insertion after rotator cuff repair in an animal model., Clinical Relevance: Drilling into the footprint and preserving the fibrocartilage can enhance repair of tendon-to-bone insertions. This method may be clinically useful in rotator cuff repair., (Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: Quantitative evaluation of vascular ingrowth to the bone tunnel walls and tendon graft after anterior cruciate ligament reconstruction for up to two years post-surgery using magnetic resonance angiography (MRA)., Methods: The study population consists of 100 patients that underwent reconstruction with multi-stranded semitendinosus tendons. The patients were retrospectively divided into those that underwent MRA two, three, four to six, and ≥ seven months after surgery (46, 17, 16, and 21 patients, respectively). Digital imaging and communication in medicine (DICOM) MRA images were imported into image processing software (OsiriX®), and the mean signal-to-noise ratio (SNR) of the bone tunnel walls in the femur and tibia and tendon graft parenchyma in the bone tunnels were measured., Results: On MRA, the signal intensities of the bone tunnel walls in the femur and tibia (12.6 ± 3.41 and 10.7 ± 3.04) were greater than that in the tendon graft (2.65 ± 1.94 and 2.50 ± 2.02, respectively) at two months after surgery. At three months after surgery, the intensities of the tendon grafts (6.25 ± 2.18 and 5.77 ± 1.57, respectively) were greater than those of the bone tunnel wall (2.56 ± 1.29 and 2.50 ± 1.11, respectively). At four to six months, the intensities in the bone tunnel wall were 1.76 ± 0.73 and 1.62 ± 0.72, respectively, and those in the tendon graft were 5.01 ± 2.11 and 4.01 ± 2.35, respectively. At ≥ seven months after surgery, the intensities in the bone tunnel wall were 1.36 ± 0.63 and 1.21 ± 0.87, respectively, and those in the tendon graft were 4.25 ± 1.87 and 3.44 ± 1.99, respectively., Conclusion: Blood flow was seen around the bone tunnel on the femoral and tibial sides two months after ACL reconstruction and in the tendon graft parenchyma three months after surgery. The remodeling process continued after seven months.

The present study aimed to diagnose complete rupture (CR) and longitudinal rupture (LR) of the posterior tibial tendon (PTT) from the magnetic resonance imaging findings in patients with PTT dysfunction and to analyze and compare the radiographs from each group to identify radiographic indicators related to the progression of PTT injury that would allow the radiographic diagnosis of CR. We evaluated 32 feet in 27 patients with PTT dysfunction (mean age 66.5, range 49 to 82, years). Radiographs were used to acquire weightbearing anteroposterior images of the foot, which were used to measure the talonavicular coverage angle. Lateral images of the foot were also acquired with the patients in the standing position. These were used to measure the lateral talometatarsal angle, calcaneal pitch angle, and medial cuneiform-fifth metatarsal height. From the axial MRI findings, the patients were divided into a CR group and an LR group, and the radiographic attributes of the CR group were analyzed. Of the 32 feet in 27 patients, 12 feet (37.5%) in 11 patients displayed CR and 20 feet (62.5%) in 18 patients displayed LR. The talonavicular coverage angle was 48.3° ± 17.3° in the CR group and 33.6° ± 13.6° in the LR group (p = .012), and the talometatarsal angle was -28.8° ± 22.5° in the CR group and -25.4° ± 14.4° in the LR group (p = .596). The calcaneal pitch angle was 10.4° ± 6.7° in the CR group and 10.2° ± 8.0° in the LR group (p = .935). Finally, the medial cuneiform-fifth metatarsal height was -4.2 ± 7.1 mm in the CR group and 2.1 ± 4.7 mm in the LR group (p = .005). When a medial cuneiform-fifth metatarsal height of ≤0 mm or talonavicular coverage angle of ≥50° was used as the diagnostic criterion for CR on weightbearing radiographs, the sensitivity was 71.4%, specificity 88.9%, and diagnostic accuracy 81.3%; hence, we believe these to be satisfactory diagnostic criteria for CR., (Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: In this study, magnetic resonance angiography (MRA) was performed in the early phase after anterior cruciate ligament (ACL) reconstruction to analyse the changes in nutrient blood vessels and blood flow to the femoral and tibial tunnels and the intraosseous tendon grafts., Methods: The subjects were 30 patients who underwent single-bundle ACL reconstruction with an autogenous hamstring tendon. MRA was performed at 2, 3, and 6 months postoperatively (n = 10 at each time point). The mean overall signal-to-noise ratios (SNRs) in the tunnel regions and in the region of the tendon graft were compared in each femur and tibia., Results: Blood vessels from arteries reached the femoral and tibial tunnels 2 months postoperatively. The tunnel walls showed high signal intensity, while the intraosseous tendon grafts had lower intensity. SNRs showed significant differences between the femoral and tibial tunnels overall and the intraosseous tendon grafts. At 3 and 6 months postoperatively, the signal intensity of the tunnel walls was decreased significantly, while that of the intraosseous tendon grafts was also decreased, but not significantly. At these times, the SNRs of the femoral and tibial tunnels did not differ significantly, both overall and in the region of the intraosseous tendon grafts., Conclusion: Revascularization around the femoral and tibial tunnels occurred at 2 months postoperatively, with blood flow subsequently decreasing over time until 6 months. This revascularization may be involved in bone tendon healing and maturation of the tendon graft within the bone tunnels. Evaluations of revascularization by MRA may show the maturation stage of the graft and guide medical rehabilitation., Level of Evidence: IV.

We present a rare case of spontaneous tendon rupture of the extensor digitorum communis (EDC) in a patient with systemic lupus erythematosus (SLE). Inflammation in SLE presents as periarthritis, which may develop into Jaccoud's arthropathy. We bridged the ruptured tendon of the EDC (III) at the metacarpophalangeal (MP) joint of this patient with a tendon graft. This case demonstrates that this portion of the MP joint can be a site of tendon rupture of fingers in SLE patients.

Circulation-derived cells play a crucial role in the healing processes of tissue. In early phases of tendon healing processes, circulation-derived cells temporarily exist in the wounded area to initiate the healing process and decrease in number with time. We assumed that a delay of time-dependent decrease in circulation-derived cells could improve the healing of tendons. In this study, we injected platelet-rich plasma (PRP) containing various kinds of growth factors into the wounded area of the patellar tendon, and compared the effects on activation of circulation-derived cells and enhancement of tendon healing with a control group (no PRP injection). To follow the circulation-derived cells, we used a green fluorescent protein (GFP) chimeric rat expressing GFP in the circulating cells and bone marrow cells. In the PRP group, the numbers of GFP-positive cells and heat-shock protein (HSP47; collagen-specific molecular chaperone)-positive cells were significantly higher than in the control group at 3 and 7 days after injury. At the same time, the immunoreactivity for types I and III collagen was higher in the PRP group than in the control group at early phase of tendon healing. These findings suggest that locally injected PRP is useful as an activator of circulation-derived cells for enhancement of the initial tendon healing process., ((c) 2008 Wiley-Liss, Inc.)

The purpose of this study is to evaluate the vascular status of autogenous semitendinosus grafts after anterior cruciate ligament reconstruction in humans using magnetic resonance angiography. Twelve patients (mean age, 24.3 years) who underwent anterior cruciate ligament reconstruction with the 4-strand semitendinosus tendon were studied. All patients underwent contrast-enhanced magnetic resonance angiography and second-look arthroscopy in their reconstructed knees on an average of 15.8 months (range 9-22 months) after surgery. Blood vessels to the graft were visualised and contrast medium enhancement for visualising the femoral tunnel, graft, and tibial tunnel was evaluated. Magnetic resonance angiography showed that a branch of the middle genicular artery extended to the upper side of the graft through the posterior capsule and that branches of the inferior genicular artery ended at the lower side of the graft in all patients. These were consistent with the actual findings of the second-look arthroscopy. We found contrast medium enhancement in the femoral and tibial tunnels in all patients. The effect of enhancement at 9 months after ACL reconstruction was higher than that at 22 months. The graft showed enhancement patterns in the posterior portion of the femoral side and the anterior portion of the tibial side. This study demonstrated that the branches of the middle and inferior genicular arteries provide blood supply to the graft, which may influence the maturation of the graft. The revascularisation of the bone tunnels could play an important role in the healing of the ligament-bone tunnel junction.

The healing of an injured musculoskeletal system requires an influx of mesenchymal cells that can differentiate into osteoblasts, fibroblasts, chondroblasts, and skeletal myoblasts. However, whether these mesenchymal cells arise from the circulation (bone marrow) or the injured tissues themselves has been controversial. To reveal the spatiotemporal characteristics of the reparative mesenchymal cells, we investigated the healing process after patellar tendon injury using two types of green fluorescent protein (GFP) chimeric rats; one expressing GFP in the circulating cells, and the other expressing it in the patellar tendon. We analyzed the behavior of GFP-positive cells after experimental tendon injury in both chimeric rats to clarify the origin of reparative cells. At 24 h after the injury, the wound contained circulation-derived cells but not tendon-derived cells. Tendon-derived cells first appeared in the wounded area at 3 days after the injury, and had significantly increased in number with time and had maintained a high level of proliferative activity until 7 days after the injury, whereas the circulation-derived cells had decreased in number and had been replaced by the tendon-derived cells. These findings suggest that circulation-derived and tendon-derived cells contribute to the healing of tendons in different periods as part of a biphasic process., (Copyright 2006 Wiley-Liss, Inc.)

We describe a new double-bundle reconstruction method for ruptured anterior cruciate ligament using a posteromedial portal technique. Reconstruction materials are semitendinosus tendon (STT) and gracilis tendon (GT). STT is used as the substitute for the anteromedial bundle (AMB) and fixed to the tunnels produced on the tibia and the femur. GT is used as the substitute for the posterolateral bundle (PLB) and fixed to the tunnels on the tibia and the femur. This femoral tunnel for the PLB is created through a posteromedial portal. These procedures are performed using the inside-out technique. The posteromedial portal provides an accurate access to the femoral attachment of the PLB. This surgical technique can avoid overlapping of the 2 femoral tunnels and destruction of the posterior cortex of the lateral condyle on the femur during the preparation of the PLB. Our technique does not need another tibial tunnel for the PLB; the 1 tibial tunnel enables double-bundle reconstruction and prevents tibial tunnel expansion.

Background: Grafting bone between the tendon graft and the bone tunnel in anterior cruciate ligament reconstruction increases the mechanical strength of the tendon graft. However, the biological role of the bone graft is unclear. The purpose of this research was to elucidate the role of bone graft cells after autologous tendon graft into the bone tunnel with an autologous bone graft in green fluorescent protein (GFP) transgenic rats. Methods: The Achilles tendons of Sprague-Dawley (SD) wild-type rats and bone of GFP rats were harvested and transplanted into bone tunnels drilled in the femurs at the knees of SD rats. The femurs were harvested at 1, 2, and 4 weeks after transplantation and histologically investigated using hematoxylin and eosin staining and immunostaining of heat shock protein 47 (HSP47), macrophages, and type I and type III collagens. Biomechanical tests were performed on the tendon graft 2 and 4 weeks after transplantation to evaluate the ultimate force to failure. Results: A small number of GFP-positive cells was seen in the tendon graft 2 weeks after transplantation. The cell count in the tendon graft was increased at 4 weeks after transplantation. HSP47-positive cells and macrophage-stained cells present in the tendon graft corresponded with the GFP-positive cells. By 2 weeks after transplantation, the relative areas of immunostained type I and III collagens in the tendon graft had declined significantly in the bone graft group compared to the control. The ultimate failure load in the bone graft group was higher than that in the control group at both 2 and 4 weeks after transplantation. Conclusions: This research showed that, within 4 weeks of transplantation, bone graft cells migrate to the tendon graft, where they differentiate into cells involved in collagen production and macrophages. Bone graft cells may contribute to the early stage remodeling of tendon grafts. [ABSTRACT FROM AUTHOR]

Background: It is difficult to evaluate the kinematics of flat foot from 2D images, and no definitive methods have so far been established to diagnose flat foot. This study evaluated hindfoot kinetics through the progression of posterior tibial tendon dysfunction (PTTD) in patients with stages II and III PTTD flat foot compared with those in normal patients under dorsiflexion and plantarflexion conditions using 3D computed tomography (CT) reconstruction images. Materials: CT images were taken of 26 normal and 32 flat feet in neutral, plantarflexion, and dorsiflexion positions of the ankle joint, from which 3D virtual models were made of each hindfoot bone. The 3D bone motion of these models was calculated using volume merge methods in three major planes. Results: Tibiotalar-joint motion in ankle-joint plantarflexion became less plantarflexed (normal −41.2°, stage II −33.5°, stage III −25.3°) and less adducted (normal −13.9°, stage II −10.7°, stage III −5.6°) as the stage progressed. Talocalcaneal-joint motion in stage III became more plantarflexed (normal −0.8°, stage II −3.0°, stage III −8.7°) and more adducted (normal −0.3°, stage II −4.7°, stage III −10.3°) as the stage progressed. Talonavicular-joint motion in stage III became more plantarflexed (normal −7.2°, stage II −7.6°, stage III −14.9°) and more adducted (normal 1.0°, stage II −7.3°, stage III −17.9°) as the stage progressed. Conclusions: Tibiotalar-joint plantarflexion decreased and talocalcaneal and talonavicular-joint adduction increased in the maximal ankle-joint plantarflexion in stage II in comparison with normal cases. Tibiotalar-joint plantarflexion and adduction were decreased and of the talocalcaneal and talonavicular joints increased in stage III in comparison with stage II cases. [ABSTRACT FROM AUTHOR]