Muhammad Andry Usman

Mechanical properties of suspensory fixation devices for anterior cruciate ligament reconstruction: Comparison of the fixed-length loop device versus the adjustable-length loop device

BACKGROUND No definite consensus has been reached regarding the optimal technique for graft fixation to the femur in an anterior cruciate ligament reconstruction. The purpose of this study was to evaluate the mechanical strength of two cortical suspension devices which were the TightRope (TR), a new adjustable-length loop device, and the EndoButton (EB), a well-established fixed-length loop device. METHODS The devices were tested under cyclic and pull-to-failure loading conditions in both an isolated device setup and a specimen setup using porcine femora and bovine flexor tendons. In particular, we examined the influence of tendon and device lengths, whereby the total length of the bone tunnel was fixed to 35 mm and an effective length of tendon in the bone tunnel was adjusted. RESULTS In the isolated device testing, the EB showed significantly higher ultimate tensile strength than the TR. The displacement after preloading for the EB was statistically lower than that for the TR, and retained a significant difference after the cyclic load. In contrast, specimen testing showed no statistical difference in the displacement among the EB group and TR groups. CONCLUSION This study indicated that the EB provides greater mechanical strength than the TR. An important new finding was the measurement of initial displacement from the initiation of fixation until loading began using 50 N of tension. In isolated device testing, the TR induced significantly more displacement than the EB during preloading, which could reflect the TR loops stretching capacity until a certain amount of tension is applied.

Proprioceptive function after isolated single-bundle posterior cruciate ligament reconstruction with remnant preservation for chronic posterior cruciate ligament injuries

INTRODUCTION Posterior cruciate ligament (PCL) reconstruction using the remnant preserving technique may contribute to improved postoperative posterior stability, graft healing, and proprioception recovery. Although there have been several reports on remnant preserving PCL reconstruction, no study has yet evaluated the proprioceptive functions before and after PCL reconstruction with remnant preservation. The purpose of this study is to retrospectively evaluate the clinical outcomes and proprioceptive function after isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries. HYPOTHESIS Isolated single-bundle PCL reconstruction with remnant preservation surgery for chronic PCL injuries provides satisfactory clinical outcomes and good recovery of the proprioceptive function. METHODS Nineteen patients who had undergone isolated single-bundle PCL reconstruction with remnant preservation for chronic PCL injuries were followed up for more than 2 years. The posterior laxity was measured by the gravity sag view, stress radiography and the KT-2000 knee arthrometer. The proprioceptive function was defined as the threshold to detect passive motion (TTDPM). RESULTS The average Lysholm score significantly improved from 63.7±13.2 preoperatively to 94.4±4.6 at final follow-up. The postoperative posterior laxity significantly improved. Regarding TTDPM, there were no significant differences between the preoperative score and the score at every given time point, regardless of the starting angles and the moving directions of the knees. CONCLUSIONS The proprioceptive function, defined as TTDPM, is maintained after single-bundle PCL reconstruction with remnant preservation, and the postoperative clinical scores and posterior laxity significantly improve. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Regenerative medicine in orthopedics using cells, scaffold, and microRNA

Cells, scaffold, and growth factors are crucially important in regenerative medicine and tissue engineering. Progress in science and technology has enabled development of these three factors, with basic research being applied clinically. In the past decade, we have investigated tissue regeneration in animal models of musculoskeletal disorders by using cells, scaffold, and delivery systems which has been relatively easy to apply and develop in clinical settings. Moreover, microRNA (miRNA), which are important in biological processes and in the pathogenesis of human diseases, have been used in research on regenerative medicine. For the cell source, we focused on mesenchymal stem cells (MSC) and CD34+ and CD133+ cells as endothelial progenitor cells for regeneration of musculoskeletal organs. These cells are accessible and safe. For less invasive and more effective therapy, we developed a novel cell-delivery system using magnetic force to accumulate cells at a desired site. Furthermore, administration of synthetic miRNA could enhance tissue regeneration. In our studies, use of these cells combined with a cell-delivery system, miRNA, scaffold, and cytokines has led to effective regeneration of musculoskeletal tissues including cartilage, bone, ligaments, muscle, peripheral nerves, and spinal cord. The current and future objective is more effective and less invasive cell-based therapy with spatial control of transplanted cells by use of an external magnetic force. Analysis of efficiency, safety, and the mechanism of tissue regeneration by cells, scaffold, and miRNA will lead to more promising regenerative medicine, involving the development of a new generation of therapy. This review will focus on our regenerative medicine research, which focuses on clinical application of cells, scaffold, and miRNA.

MicroRNAs and Bone Regeneration

Bone has multiple functions, both morphologically and physiologically, and it frequently features in the pathological condition, including fracture and osteoporosis. For bone regeneration therapy, the regulation of osteoblast differentiation is important. MicroRNA (miRNA)s are short noncoding RNA which regulate gene expression at the post-transcriptional level. MiRNAs play an important role not only in a variety of other cellular processes including differentiation, proliferation, and apoptosis but also in the pathogenesis of human diseases. Recently, miRNAs have been known to participate in osteoblast differentiation by regulating several signaling pathways including transcription factors. New insight into the mechanism during osteogenes is affected by miRNAs has been gained. Moreover, therapeutic trials for bone diseases including osteoporosis, fracture and bone defects targeting miRNAs have been examined in animal models. MiRNA therapy will enable development of a bone regeneration therapy.

Revision single-bundle anterior cruciate ligament reconstruction with over-the-top route procedure

PURPOSE In revision anterior cruciate ligament reconstruction (ACLR), the single-stage technique and the over-the-top route (OTTR) procedure were usually selected for cases where the bone tunnel cannot be created at an anatomical position due to tunnel enlargement and overlap with the mal-positioned tunnel of primary reconstruction. The purpose of this study was to evaluate the clinical results of revision single-bundle ACL reconstruction using OTTR procedure and to compare the clinical results of OTTR procedure with those of anatomical single-bundle revision reconstruction (SBR). HYPOTHESIS The results of OTTR procedure are equivalent to that of SBR. METHODS Seventy-six revision ACL reconstruction knees from April 2002 to December 2012 were involved in our study. We focused on 21 knees which underwent surgery with SBR and 22 knees with OTTR using hamstring tendon. The clinical results were evaluated by means of the Lysholm score and the knee stability was assessed by the Lachman test, pivot-shift test and side-to-side difference by KT-2000 pre-operatively and after 1 year post-operatively. AP translation and rotational laxity using a navigation system were evaluated before and after revision ACL reconstruction under anesthesia in 8 cases of OTTR and in 6 cases of SBR. RESULTS There was no statistically significant difference between the OTTR and SBR regarding Lysholm score, Lachman test, pivot-shift test, ATT by KT-2000, and AP translation and rotational laxity with a navigation system. CONCLUSIONS The clinical results of OTTR are almost equivalent to those of SBR. For the cases in which it is impossible to create the femoral tunnel in an anatomical position, OTTR is a valuable revision ACL reconstruction method. LEVEL OF EVIDENCE Case-control study. Level III.

A new distraction arthroplasty device using magnetic force; a cadaveric study

BACKGROUND It is difficult for an articular cartilage injury to repair spontaneously. There are many procedures for treating cartilage injury, however there is no standard procedure for middle-aged patients who have diffuse knee osteoarthritis, especially of the lateral compartment. Therefore, Ochi developed a new distraction device that uses magnetic power to enlarge a joint space and promote cartilage regeneration with microfracture. The purpose of this study is to evaluate this new distraction arthroplasty system by using the cadaveric knee. METHODS This study used ten knees from six cadavers that were embalmed by Thiels methods. The medial and lateral joint space was measured by AP radiographic view before and after distraction, and after weight-bearing to evaluate the joint distraction. The contact pressure of the medial and lateral compartments at the knee extension position by using a prescale film system was measured before and after weight-bearing with a 15 or 30-kg weight-bearing load to evaluate the effectiveness of this device. FINDINGS The lateral joint space significantly increased from the pre-distraction to the post-distraction; however, it did not change significantly between post-distraction and post-weight-bearing. With a 15 or 30-kg weight-bearing load, the contact pressure of the lateral compartment significantly decreased from the pre-distraction to the post-distraction. INTERPRETATION The most important advantage of this device is that it maintains a continuous distraction tension and enables almost the full range of motion of the knee. We believe that joint distraction by using magnetic force can be a promising option for cartilage injury in middle-aged patients.

A new technique to avoid articular cartilage injury in anterior cruciate ligament reconstruction through far antero-medial portal.

Far antero-medial (FAM) portal technique is usually used in our department in anterior cruciate ligament (ACL) reconstruction when drilling the femoral tunnel. Although the FAM portal technique carries potential risks, such as cartilage injury of the lateral femoral condyle, peroneal nerve injury and blow out of the lateral femoral condyles posterior wall, these problems were resolved in a cadaveric study, in which 110°-120°knee flexion was recommended when drilling the femoral tunnel. However, there is a potential risk of injuring the cartilage of the medial femoral condyle especially when drilling the postero-lateral bundle. A new method is proposed to ensure that the femoral tunnel drilling does not damage the cartilage of the medial femoral condyle.

Acceleration of healing of the medial collateral ligament of the knee by local administration of synthetic microRNA-210 in a rat model

Background Injury to the medial collateral ligament (MCL) of the knee joint is the most common ligament injury of the knee. Ligament healing generally takes a long time. Micro-ribonucleic acid (miRNA) is one of the noncoding RNAs and plays a crucial role in physiological function; miRNA (miR)-210 is known as a potent factor of angiogenesis, which is an important initiator of ligament healing. The purpose of this study is to examine the effect of local injection of double-stranded (ds) miR-210 on the healing of the MCL of rat knee joint. Methods MCLs of Sprague-Dawley rats were cut transversely. After the fascia and skin were sutured, dsmiR-210 or control dsRNA was injected into the injured site of MCL. At 2 weeks and 4 weeks, histological analysis and immunofluorescence staining of vascular endothelial growth factor, isolectin B4, collagen type 1, and Ki67 as well as a mechanical test were performed. Analysis of complementary deoxyribonucleic acid (cDNA) microarray data was performed at 1 week. Results Histological analysis showed that parallel fibres in the injured site were organised at 2 weeks and became thicker at 4 weeks in the miR-210-treated group, whereas the injured site in controls was filled with loose fibrous tissues and was thinner than that in the miR-210-treated group. The number of blood vessels in the miR-210-treated group was significantly higher than that in controls (p < 0.05), and vascular endothelial growth factor, Ki67, and collagen type 1 in the miR-210-treated group were intensely expressed in the repaired site as compared to the control group. The mechanical test indicated that the ultimate failure load in the miR-210-treated group was significantly higher than that in the control group at 2 weeks. The cDNA microarray analysis showed significant upregulation of genes related to cell proliferation and cell differentiation, and genes involved in negative regulation of apoptosis. Conclusion This study showed that local injection of dsmiR-210 could accelerate MCL healing in rat, which is likely due to stimulation of angiogenesis at the healing site.