Norinao Matsumoto

Results of isolated meniscal repair evaluated by second-look arthroscopy

Thirty-six isolated torn menisci in 35 patients (average age, 24 years) which had been repaired arthroscopically using an inside-out technique were evaluated by second-look arthroscopy. The time from meniscal repair to second-look arthroscopy ranged from 2 to 10 months with a mean of 5 months. The indications for meniscal repair were a longitudinal or oblique tear located at the outer half of the meniscus. Twenty (56%) were graded as excellent, 10 (28%) as good, and 6 (16%) were graded as poor. Neither age nor length of time between injury and repair affected meniscal healing. The medial meniscal repairs showed better results than the lateral repairs (rate of excellent results: medial, 82%; lateral, 44%; P < .01, chi-squared test). The rate of excellent results for those with normal meniscal bodies at the time of repair was 79%, which was significantly higher than that seen in the cases with deformed and/or superficial damage to the meniscal body (36%; P < .05, chi-squared test).

Second-look arthroscopy after meniscal repair. Review of 132 menisci repaired by an arthroscopic inside-out technique

From 1986 to 1993, we repaired 278 torn menisci in 264 patients using an arthroscopically assisted inside-out technique. A total of 132 meniscal repairs in 122 patients were evaluated by second-look arthroscopy. At review, only nine patients had meniscal symptoms, such as locking, swelling or pain. Ninety-seven menisci (73%) had healed completely at the repair site, but there were new tears in different areas of 21 menisci, some of which had complete healing at the repair site. Incomplete healing, seen in 23 menisci (17%), was frequently near the popliteus tendon, most commonly where there had been an associated anterior-cruciate-ligament injury. Arthroscopically-assisted meniscal repair seems to be a reliable procedure, but some clinically successful cases had incomplete healing at the repair site or a newly-formed tear in the meniscal body or both. These lesions may cause meniscal symptoms to appear at a later date.

Arthroscopic posterior cruciate ligament reconstruction using hamstring tendons: One-incision technique with Endobutton

The one-incision surgical technique using autogenous hamstring tendons with Endobutton (Acufex Microsurgical Inc. Mansfield, MA) femoral end fixation for posterior cruciate ligament reconstruction is described. This technique avoids a second incision on the femoral side, and is adaptable to various graft materials (autogenous or allogeneic bone-patellar tendon-bone, hamstring, or Achilles tendon.

Migration of EndoButton After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE The purpose of this study was to (1) assess the migration of EndoButtons (Smith & Nephew Endoscopy, Andover, MA) with or without tissue interposition by comparing the radiographs obtained immediately after anterior cruciate ligament (ACL) reconstruction and those obtained during the follow-up period and (2) investigate the effect of tissue interposition or migration of EndoButtons on the clinical outcomes. METHODS One hundred one patients underwent anatomic double-bundle ACL reconstruction with EndoButtons for femoral fixation. Anteroposterior and lateral radiographs were taken immediately postoperatively and at 1 week, 1 month, 3 months, and 1 year. The distance between the EndoButton and lateral femoral cortex was measured on the radiograph obtained immediately postoperatively, and more than 1 mm in distance was defined as positive tissue interposition. Moreover, the locations of the EndoButtons on the radiographs obtained at each follow-up visit were compared with those obtained immediately postoperatively, and EndoButton migration was considered to be present when the EndoButton had moved more than 1 mm or had rotated by more than 5°. The relations between clinical outcomes at 1 year and tissue interposition or migration of EndoButtons were also evaluated. RESULTS Tissue interposition was found for 51 EndoButtons and migration was observed for 71 EndoButtons, and there was a significant difference in the incidence of migration between anteromedial and posterolateral grafts. Of the 51 EndoButtons with tissue interposition, 32 migrated within 1 year, and 39 of 151 EndoButtons without tissue interposition migrated, whereas the EndoButtons with tissue interposition migrated significantly more frequently. On the other hand, there were no significant differences in clinical outcomes between the cases with or without tissue interposition and between the cases with or without EndoButton migration. CONCLUSIONS Tissue interposition between the EndoButton and femoral lateral cortex was found in 51 EndoButtons (25.2%) on the radiographs obtained immediately after ACL reconstruction, whereas EndoButtons with tissue interposition migrated more frequently than those without it 1 year after ACL reconstruction. However, neither tissue interposition nor migration of the EndoButton affected the clinical outcomes. LEVEL OF EVIDENCE Level IV, prognostic case series.

Effect of alignment of the transplanted graft extracellular matrix on cellular repopulation and newly synthesized collagen

Abstract This study examines the effect of alignment of the transplanted graft extracellular matrix on cellular repopulation and new collagen synthesis. The lateral half of the patellar tendon was harvested as a tendon graft from Lewis rats and frozen at –80° C. In order to maintain the original alignment of the graft extracellular matrix, the graft was transplanted to a same size defect in the patellar tendon of other Lewis rats (group I). For controls, the graft was transplanted in a lax condition after excision of only the distal half of the lateral side of a patellar tendon (group II). After transplantation, six animals in each group were killed at 3, 7, 14, and 28 days. Cellular repopulation was assessed by using fibrillar-actin (F-actin) labeling with rhodamine-phalloidin, and new collagen synthesis was detected by means of a polyclonal antibody against type III collagen aminopropeptide (pN collagen III). Collagen fibril profiles were observed under the transmission electron microscope. On the 3rd day after transplantation, no specific fluorescence was detected in either group. Specific labeling for F-actin and pN collagen III, however, was observed at both ends of the graft in both groups at 1 week and throughout the graft at 2 weeks after transplantation. Consistent with the actin bundles’ orientation, pN collagen III was aligned parallel to the longitudinal axis of the graft in group I. Collagen fibrils with a smaller diameter, mixed evenly and everywhere with a larger diameter, increased gradually in group I. However, smaller collagen fibrils in group II increased more slowly and were distributed unevenly. In summary, the dense collagen arrangement in the native patellar tendon determined the alignment of the repopulating cells, and the distribution of newly synthesized collagen might be affected by the actin cytoskeleton within the repopulating cells.

Graft Tension During Active Knee Extension Exercise in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE The purpose of this study was to measure graft tension in vivo in anatomic double-bundle anterior cruciate ligament (ACL) reconstruction during active knee extension, as well as to investigate the effect of loading a weight around the ankle on graft tension. METHODS Seven patients with chronic ACL injury underwent anatomic double-bundle ACL reconstruction. Two grafts were temporarily fixed to the 2 tension-adjustable force gauges on the anterior tibial cortex, after they were fixed on the femur. After the creep within the femur-ACL graft-tibia construct was removed, 10 N of the initial tension was applied to each graft at 20 degrees. First, tension to the anteromedial (AM) and posterolateral (PL) grafts was continuously measured during passive extension from 90 degrees to 0 degrees with the patient under general anesthesia. Then, after the patient was awoken from anesthesia, graft tension was again recorded while the knee was actively extended by the patient in the same manner. Finally, after a 2-kg weight was placed around the ankle, the tension of each graft was measured again during active knee extension by the patient himself or herself. RESULTS During passive extension motion, the tension of the AM graft was 19.3 +/- 4.7 N, whereas that of the PL graft was 24.5 +/- 5.9 N at 0 degrees. The tension of each graft increased when approaching full extension. During active knee extension motion, the tension of the AM graft was 24.0 +/- 6.1 N, whereas that of the PL graft was 30.8 +/- 7.3 N at 0 degrees. When the 2-kg weight was placed around the ankle during active motion, the tension was significantly higher than that with no weight at all flexion angles. CONCLUSIONS Graft tension was greater during active motion than that during passive motion, and graft tension during active motion increased with a weight placed around the ankle. The highest graft tension was 62.8 N at 0 degrees of flexion with a 2-kg weight placed around the ankle, when 20 N of initial tension was applied at 20 degrees of flexion in anatomic double-bundle ACL reconstruction. Thus care must be taken during active extension exercise with weights, especially in the first few weeks after ACL reconstruction, because graft tension increases with an increase in initial tension and easily reaches a critical level. CLINICAL RELEVANCE Our findings suggest that active knee extension exercise should be performed in moderation in the early phase after ACL reconstruction.

Solvent-dried and gamma-irradiated tendon allografts in rats

We examined solvent-dried, gamma-irradiated (SD-R) allografts and fresh-frozen (FF) allografts mechanically and morphologically. Before transplantation, FF grafts were more than six times stronger than SD-R grafts. After four weeks, the tensile strength was about the same in both groups. At 24 weeks only collagen fibrils of small diameter were observed in the SD-R grafts while in FF grafts fibrils of small and intermediate diameter were seen. Clinically, we suggest that SD-R grafts could be used as a favourable alternative to FF grafts if care was taken regarding their initial mechanical weakness.

Intraarticular ganglion cyst around the cruciate ligament of the knee

Abstract Intraarticular ganglion cysts arising from the cruciate ligaments are encountered infrequently. We report two cases in which intraarticular ganglion cysts arising from the anterior cruciate ligament and the posterior cruciate ligament, respectively. In both cases, dull pain in the full flexion position was observed and magnetic resonance imaging was helpful for the preoperative diagnosis.

In Vivo Graft Tension in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction During Active Leg-Raising Motion With the Knee Splinted

PURPOSE The purpose of this study was to measure the in vivo graft tension in anatomic 2-bundle anterior cruciate ligament (ACL) reconstruction during active leg-raising exercise with the knee immobilized. METHODS Anatomic double-bundle ACL reconstruction was performed with autogenous semitendinosus tendons in 7 patients while under general anesthesia. Two grafts were fixed with 2 EndoButton-CL devices (Smith & Nephew Endoscopy, Andover, MA) on the femur and were temporarily fixed to 2 tension-adjustable force gauges on the anterior tibial cortex. Then, a knee brace in semi-flexion was put around the knee, and 10 N of initial tension was applied to each graft at 20° of flexion. The tension on the anteromedial (AM) and posterolateral (PL) grafts was continuously measured during active leg-raising motion with the knee immobilized after patients had awoken from anesthesia. Then, the tension measurement was repeated during active leg-raising motion with the knee immobilized while a 2-kg weight was fitted around the ankle. RESULTS In situ graft tension during active leg-raising motion with a knee brace was 10.9 ± 4.0 N for the AM graft and 8.6 ± 5.1 N for the PL graft, whereas the tension with a 2-kg weight around the ankle was 10.9 ± 3.4 N for the AM graft and 9.9 ± 3.6 N for the PL graft. There was no significant difference between each graft in the 2 motions with a paired t test. CONCLUSIONS Graft tension with the knee immobilized with a semi-flexed knee brace during active leg-raising motion was 19.5 N with no weight and 20.8 N with additional weight, both of which were almost equal to the initial graft tension at the time of fixation at 20°. Thus the leg-raising exercise can be recommended as safe when a semi-flexed knee brace is worn after ACL reconstruction. CLINICAL RELEVANCE These findings will help to plan postoperative rehabilitation programs with security.

Progression of cellular repopulation and collagen synthesis in fresh‐frozen allograft tendons

The progression of cellular repopulation and collagen synthesis in fresh‐frozen rat patellar tendon allografts was investigated by means of indirect immunofluorescence histologic analysis and electron microscopic techniques for 8 weeks after transplantation. In each of 10 procedures, the medial half of the patellar tendon with a tibial bone block was harvested from a Wistar rat and transplanted into a corresponding defect in the medial patellar tendon of a Lewis rat. Actin filaments in the repopulating cells and newly synthesized collagen fibrils in the graft were identified with rhodamine‐phalloidin stain and with a polyclonal antibody against type III collagen aminopro‐peptide. On the first day after transplantation, no specific fluorescence was detected in the graft. One week later, specific labeling for fibrillar‐actin (F‐actin) and type III collagen aminopropeptide was detected in an area extending from the adjacent granulation tissue into the proximal end of the graft. F‐actin and type III collagen aminopropeptide were aligned along the longitudinal axis of the graft and extended from the proximal suture site toward the distal portion. Two weeks after transplantation, fibrillar labeling for F‐actin and type III collagen amino‐propeptide showed that remodeling had extended to the midportion of the graft. Labeling throughout the entire graft was detected 4 weeks after transplantation. During the entire remodeling process, the repopulated fibroblasts consistently retained their elongated shape and their alignment with the longitudinal axis of the graft. The cells developed well‐organized actin bundles at their peripheries, which identified them as having a myofibroblast phenotype. Immunofluorescence detection for type III collagen aminopropeptide also showed consistent alignment parallel to the longitudinal axis of the graft and a fibrillar arrangement. Electron microscopy revealed thinner collagen fibrils in the vicinity of the fibroblasts, which were aligned in the direction of the actin bundles. These results indicate that, during the early remodeling phase, collagen synthesis and deposition in the graft proceeds while the original alignment of the graft matrix is preserved. The close association between the alignment of actin bundles in repopulated “myofibroblastic” cells and that of newly synthesized collagen fibrils along the lines of the graft matrix may represent evidence of force transmission between the actin cytoskeleton and the linking extracellular matrix in vivo.