Knee Surgery, Sports Traumatology, Arthroscopy, May 10, 2021
The objective of this study was to investigate factors that influence the prevalence of medial an... more The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries. Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy. In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027). Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions. Level III.
Knee Surgery, Sports Traumatology, Arthroscopy, May 5, 2010
We read with great interest the article from Viana’s group entitled ‘‘Mucoid degeneration of the ... more We read with great interest the article from Viana’s group entitled ‘‘Mucoid degeneration of the anterior cruciate ligament: magnetic resonance imaging findings of an underdiagnosed entity’’ [2] and Viana’s article ‘‘Diffuse intrasubstance signal abnormalities of the posterior cruciate ligament: the counterpart of the mucoid degeneration of the anterior cruciate ligament? A case series’’ [8]. First, we have to apologize to Dr. Viana and the editor for our ignorance in our paper [6] regarding the paper from the Viana group about anterior cruciate ligament (ACL) mucoid degeneration [2], even though we cited in our references that article written in 2008. We accidentally discovered the paper just before we submitted our paper to the Editorial office of Knee Surgery, Sports Traumatology, Arthroscopy in October, 2008. Therefore, we made a mistake in that we did not make any mention about the paper even though we cited it in our references. We totally agree with Dr. Viana that the posterior cruciate ligament (PCL) mucoid degeneration seen by magnetic resonance imaging (MRI) [8] represents the counterpart of the mucoid degeneration of the ACL and that orthopedists and radiologists often clinically encounter the coincidence of the mucoid degeneration of both the ACL and PCL in the same patient. Viana reported 7 cases of PCL mucoid degeneration using MRI in his paper [8]. Six patients were a coincidence of both ACL and PCL mucoid degeneration, and 1 patient was PCL mucoid degeneration alone. Several papers have already reported that coexistence of both ACL and PCL mucoid degeneration in the degenerative knee, as Viana mentioned [1, 3, 4, 5, 7]. Dr. Viana’s article and his letter confirmed that PCL mucoid degeneration does exist without ACL mucoid degeneration. We are very interested in Viana’s one case, which showed a limited range of motion with PCL mucoid degeneration without ACL mucoid degeneration or degenerative arthritis. This case is quite similar with our case. In any case, it is our great pleasure that Viana already reported a 30-year-old woman complaining of a limited range of motion with PCL mucoid degeneration alone in the November–December 2008 issue of a different journal. We should have revised our paper, because we knew about Viana’s report of a rare case of PCL mucoid degeneration without ACL mucoid degeneration. Therefore, we made a mistake in our paper. We are very interested in Viana’s case. He reported a very similar MRI appearance of the PCL in his case when compared to our case, a ‘‘tramtrack’’-like sign with a core high signal intensity in T2-weighted images surrounded by a rim of low signal in sagittal images, mostly posteriorly and superiorly that Viana speculated as representing PCL mucoid degeneration. Viana made comments only on the MRI appearance and clinical symptoms. It was a small disappointment that he did not make any comments about her clinical treatment, histological examination or clinical course. These data will help many orthopedists and radiologists understand this rare entity of PCL mucoid degeneration alone. We also emphasized the role of MRI as a non-invasive tool in the diagnosis of purely intrasubstance ligamentous abnormalities. Finally, Dr. Viana is very kind to let us know the PCL mucoid degeneration does exist in middle-aged patients without ACL degeneration and that the clinical symptoms are a limited range of motion without a history of trauma or T. Shoji E. Fujimoto (&) Y. Sasashige Department of Orthopedic Surgery, Chugoku Rousai Hospital, 1-5-1 Hirotagaya, Kure, Hiroshima 737-0193, Japan e-mail: eisaku-fjm@umin.ac.jp
The objective of this study was to investigate factors that influence the prevalence of medial an... more The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries. Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy. In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027). Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions. Level III.
The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against th... more The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against the posterior cruciate ligament (PCL) with the knee in an extended position, which arthroscopy cannot detect. Ten normal knees and 30 ACL-reconstructed knees were assessed using MR imaging. The three-dimensional reconstruction of the ACL, PCL, femur and tibia were carried out using commercially available three-dimensional reconstruction software. Anterior cruciate ligament impingement against the PCL was graded into three categories: Grade 1, some space between the ligaments; Grade 2, no space between the ligaments, and the reconstructed ACL ran straight; and Grade 3, the reconstructed ACL did not run straight. The angle of the reconstructed ACL against the tibial plateau was also measured. All normal knees were classified as Grade 1. The 30 reconstructed knees were classified as follows: Grade 1, 12 cases; Grade 2, 7 cases; and Grade 3, 11 cases. The mean angle of the Grade 3 reconstructe...
Eighty-nine cases after anterior cruciate ligaments (ACL) reconstruction were followed prospectiv... more Eighty-nine cases after anterior cruciate ligaments (ACL) reconstruction were followed prospectively with magnetic resonance imaging (MRI). The patients were examined using axial and sagittal MRI at least twice during the postoperative evaluation of reconstructed ACL. Two cases of pretibial cyst formation were observed. At the time of cyst formation, neither patient had any subjective or objective evidence of knee instability. The cyst of one case communicated with the intra-articular. The minimum follow-up period after the surgical excision was 9 months, with no evidence of recurrence. We might speculate that the critical period for cyst formation in both patients occurred at less than 12 months after their ACL reconstruction. We concluded that the cyst formation was most likely due to incomplete graft tendon incorporation within the osseous tunnel.
The objective of this study was to observe the changing appearance of human anterior cruciate lig... more The objective of this study was to observe the changing appearance of human anterior cruciate ligament (ACL) grafts in their tibial bone tunnels by MRI using oblique axial images. One-hundred and eight knees in 75 patients were studied by MRI at 1-33 months after arthroscopic ACL reconstructions using double-looped, autogenous semitendinosus and/or gracilis tendons. Knees with poor stability were excluded from this study. The examinations were performed at 0.2T with spin echo proton density and T2-weighted oblique axial images. Appearances of grafts were mainly described on spin echo proton density images based upon time after surgery. The grafts appeared as homogeneous, low signal intensity areas in the bone tunnels at 1 month after the surgery. Ring-shaped low signal intensity areas were observed along the wall of the bone tunnels in the 2- to 3-month group. In many grafts from this group, each tendinous bundle appeared as a low signal area separated by a high signal intensity area. In all cases in the 4- to 6-month group, the thickness of the ring-shaped low signal intensity area had increased, whereas the thickness of the high signal intensity area had decreased. In almost all of the cases, the interior of the bone tunnel gradually became a homologous low signal intensity region by 7 to 12 months after the surgery. According to these results, it is suggested that the maturation of the tendon-bone interface was completed from 6 to 12 months after the ACL reconstruction.
Archives of Physical Medicine and Rehabilitation, 2004
To evaluate the actual date of the return to activity and its impact on the postsurgical stabilit... more To evaluate the actual date of the return to activity and its impact on the postsurgical stability of anterior cruciate ligament reconstruction (ACLR) using hamstring grafts. A retrospective analysis. The time of return to activity was determined by a questionnaire at 24 to 36 months after ACLRs. An orthopedic center. Fifty consecutive patients who had ACLRs using hamstring grafts 24 to 36 months earlier. Not applicable. Main outcome measure The time of return to activity from a questionnaire and serial KT-2000 data at 3, 6, 12, 18, and 24 months postsurgery. Patients were divided into 2 groups according to their KT-2000 side-to-side difference at 12, 18, and 24 months postsurgery. Group I consisted of patients whose differences were 3mm or less. Group II consisted of patients whose differences were more than 3mm. At 12 and 18 months postsurgery, significant differences were detected for the time of return to running and full-speed running. A multiple regression analysis for postsurgical stability at 24 months and the time of return to these 5 activities indicated that the time of return to full-speed running and sports activities had an effect on ACL stability. An early return to vigorous activities is not recommended in patients undergoing ACLRs with hamstring grafts.
Schwann cell basal lamina tubes serve as attractive conduits for regeneration of peripheral nerve... more Schwann cell basal lamina tubes serve as attractive conduits for regeneration of peripheral nerve axons. In the present study, by using basal lamina tubes prepared by in situ freeze-treatment of rat saphenous nerve, the effects of exogenously applied basic fibroblast growth factor (bFGF) on peripheral nerve regeneration was examined 2 and 5 days after bFGF administration. Regenerating axons were observed by light and electron microscopy using PGP9.5-immunohistochemistry for specific staining of axons. In addition, the localizations of bFGF and its receptor (FGF receptor-1) were examined by immunohistochemistry using anti-bFGF antibody and anti-FGF receptor-1 antibody, respectively. Regenerating axons extended further in the bFGF-administered segment than in the bFGF-untreated control segment. Electron microscopy showed that regenerating axons grew out unaccompanied by Schwann cells. Findings concerning angiogenesis and Schwann cell migration were very similar between the bFGF treate...
The aim of this study was to examine the effects of prelesioned peripheral nerve grafts on centra... more The aim of this study was to examine the effects of prelesioned peripheral nerve grafts on central nerve regeneration compared with the freshly transected peripheral nerve grafts in the dorsal funiculus of the rat spinal cord. The experimental paradigm consisted of ligating the common peroneal nerve at the midthigh level for 7 days, while the adjacent tibial nerve was left intact. Numerous Schwann cells appeared accompanying regenerating axons in the proximal stump of the ligated nerve. The proximal stumps of the ligated (prelesioned) common peroneal nerve and the intact (untreated) tibial nerve were excised as one tissue block and autografted into the dorsal funiculi of the upper cervical cord. The graft was placed so that the prelesioned common peroneal nerve was positioned on the left dorsal funiculus and the untreated tibial nerve was positioned to the right of the midsagittal plane. Nerve regeneration was examined by light and transmission electron microscopy 1 to 16 weeks after grafting, comparing the effectiveness of prelesioned and untreated nerve grafts. Numerous regenerating axons were observed in the caudal border of both grafts 1 to 2 weeks after grafting. Astrocyte proliferation was suppressed in the prelesioned grafts compared to the untreated grafts. Four to 16 weeks later, the number of regenerating axons was approximately 10-fold as large in the prelesioned grafts as in the untreated grafts. The regenerating axons were myelinated by Schwann cells. Astrocytic glial scar formation was inconspicuous in the prelesioned grafts, whereas it was prominent in the untreated grafts. Schwann cells were contiguous with astrocytes along regenerating axons, forming a continuous conduit from the central to peripheral nerve microenvironments for the outgrowth of regenerating axons. The prelesioned peripheral nerve graft is more effective than the untreated graft in suppressing astrocytic scar formation and in supporting the outgrowth of regenerating axons in the dorsal funiculus of rat spinal cord.
Traumatic degeneration of myelinated fibers was studied by electron microscopy over 5 days follow... more Traumatic degeneration of myelinated fibers was studied by electron microscopy over 5 days following transection of mouse sciatic nerve. Special attention was paid to the mechanism which separates the degenerating part, while preserving the viable part of the axon. Immediately after transection, the opened end of the proximal stump revealed extensive subcellular changes including the disorganization of neurofilaments, and disruption of mitochondria and axonal endoplasmic reticulum (SER). Subsequently, vesicles of round and tubular profiles filled up the whole area of the stump end, and proximal to it appeared a neurofilament-predominant area characterized by randomly oriented neurofilaments and normally appearing mitochondria and SER. Characteristic membranous demarcations occurred in early periods at the border between the vesicle accumulation and the neurofilament-predominant areas, and later also within these areas. The demarcation membranes formed both by invagination of the surface plasma membrane and, probably, by fusion of the large vesicles. These became prominent with time, dividing the axoplasm into compartments of varying sizes, which gradually underwent degeneration and were liberated from the parent axon. Occurrence of autophagic vacuoles was characteristic of the degenerating portions of the parent axon. Thus, by the function of demarcation membranes, the parent axon to be preserved could remain membrane-bound, while the degenerating parts were shed off.
Knee Surgery, Sports Traumatology, Arthroscopy, May 10, 2021
The objective of this study was to investigate factors that influence the prevalence of medial an... more The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries. Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy. In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027). Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions. Level III.
Knee Surgery, Sports Traumatology, Arthroscopy, May 5, 2010
We read with great interest the article from Viana’s group entitled ‘‘Mucoid degeneration of the ... more We read with great interest the article from Viana’s group entitled ‘‘Mucoid degeneration of the anterior cruciate ligament: magnetic resonance imaging findings of an underdiagnosed entity’’ [2] and Viana’s article ‘‘Diffuse intrasubstance signal abnormalities of the posterior cruciate ligament: the counterpart of the mucoid degeneration of the anterior cruciate ligament? A case series’’ [8]. First, we have to apologize to Dr. Viana and the editor for our ignorance in our paper [6] regarding the paper from the Viana group about anterior cruciate ligament (ACL) mucoid degeneration [2], even though we cited in our references that article written in 2008. We accidentally discovered the paper just before we submitted our paper to the Editorial office of Knee Surgery, Sports Traumatology, Arthroscopy in October, 2008. Therefore, we made a mistake in that we did not make any mention about the paper even though we cited it in our references. We totally agree with Dr. Viana that the posterior cruciate ligament (PCL) mucoid degeneration seen by magnetic resonance imaging (MRI) [8] represents the counterpart of the mucoid degeneration of the ACL and that orthopedists and radiologists often clinically encounter the coincidence of the mucoid degeneration of both the ACL and PCL in the same patient. Viana reported 7 cases of PCL mucoid degeneration using MRI in his paper [8]. Six patients were a coincidence of both ACL and PCL mucoid degeneration, and 1 patient was PCL mucoid degeneration alone. Several papers have already reported that coexistence of both ACL and PCL mucoid degeneration in the degenerative knee, as Viana mentioned [1, 3, 4, 5, 7]. Dr. Viana’s article and his letter confirmed that PCL mucoid degeneration does exist without ACL mucoid degeneration. We are very interested in Viana’s one case, which showed a limited range of motion with PCL mucoid degeneration without ACL mucoid degeneration or degenerative arthritis. This case is quite similar with our case. In any case, it is our great pleasure that Viana already reported a 30-year-old woman complaining of a limited range of motion with PCL mucoid degeneration alone in the November–December 2008 issue of a different journal. We should have revised our paper, because we knew about Viana’s report of a rare case of PCL mucoid degeneration without ACL mucoid degeneration. Therefore, we made a mistake in our paper. We are very interested in Viana’s case. He reported a very similar MRI appearance of the PCL in his case when compared to our case, a ‘‘tramtrack’’-like sign with a core high signal intensity in T2-weighted images surrounded by a rim of low signal in sagittal images, mostly posteriorly and superiorly that Viana speculated as representing PCL mucoid degeneration. Viana made comments only on the MRI appearance and clinical symptoms. It was a small disappointment that he did not make any comments about her clinical treatment, histological examination or clinical course. These data will help many orthopedists and radiologists understand this rare entity of PCL mucoid degeneration alone. We also emphasized the role of MRI as a non-invasive tool in the diagnosis of purely intrasubstance ligamentous abnormalities. Finally, Dr. Viana is very kind to let us know the PCL mucoid degeneration does exist in middle-aged patients without ACL degeneration and that the clinical symptoms are a limited range of motion without a history of trauma or T. Shoji E. Fujimoto (&) Y. Sasashige Department of Orthopedic Surgery, Chugoku Rousai Hospital, 1-5-1 Hirotagaya, Kure, Hiroshima 737-0193, Japan e-mail: eisaku-fjm@umin.ac.jp
The objective of this study was to investigate factors that influence the prevalence of medial an... more The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries. Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis. Meniscal conditions were evaluated via arthroscopy. In all, 830 patients were enrolled. The prevalence of medial and lateral meniscal tears was 32.0% (266 knees) and 26.5% (220 knees), respectively. Significant factors that influenced the prevalence of medial meniscal injuries were age [odds ratio (OR) 1.03; P = 0.000], side-to-side differences in instrumented anterior knee laxity before surgery (OR 1.12; P = 0.002), duration between injury and surgery (≥ 12 months) (OR 1.86; P = 0.023), and pivot shift test grade (OR 1.36; P = 0.014). Significant factors of lateral meniscal injury were side-to-side differences in anterior knee laxity before surgery (OR 1.12; P = 0.003) and the male sex (OR 1.50; P = 0.027). Greater anterior knee laxity, age, a longer duration between injury and surgery, and a higher pivot shift test grade predicted medial meniscal injury. Greater anterior knee laxity and the male sex predicted lateral meniscal injury. In patients with ACL injuries, the importance of side-to-side differences in anterior knee laxity should be rediscovered from the viewpoint of meniscal conditions. Level III.
The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against th... more The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against the posterior cruciate ligament (PCL) with the knee in an extended position, which arthroscopy cannot detect. Ten normal knees and 30 ACL-reconstructed knees were assessed using MR imaging. The three-dimensional reconstruction of the ACL, PCL, femur and tibia were carried out using commercially available three-dimensional reconstruction software. Anterior cruciate ligament impingement against the PCL was graded into three categories: Grade 1, some space between the ligaments; Grade 2, no space between the ligaments, and the reconstructed ACL ran straight; and Grade 3, the reconstructed ACL did not run straight. The angle of the reconstructed ACL against the tibial plateau was also measured. All normal knees were classified as Grade 1. The 30 reconstructed knees were classified as follows: Grade 1, 12 cases; Grade 2, 7 cases; and Grade 3, 11 cases. The mean angle of the Grade 3 reconstructe...
Eighty-nine cases after anterior cruciate ligaments (ACL) reconstruction were followed prospectiv... more Eighty-nine cases after anterior cruciate ligaments (ACL) reconstruction were followed prospectively with magnetic resonance imaging (MRI). The patients were examined using axial and sagittal MRI at least twice during the postoperative evaluation of reconstructed ACL. Two cases of pretibial cyst formation were observed. At the time of cyst formation, neither patient had any subjective or objective evidence of knee instability. The cyst of one case communicated with the intra-articular. The minimum follow-up period after the surgical excision was 9 months, with no evidence of recurrence. We might speculate that the critical period for cyst formation in both patients occurred at less than 12 months after their ACL reconstruction. We concluded that the cyst formation was most likely due to incomplete graft tendon incorporation within the osseous tunnel.
The objective of this study was to observe the changing appearance of human anterior cruciate lig... more The objective of this study was to observe the changing appearance of human anterior cruciate ligament (ACL) grafts in their tibial bone tunnels by MRI using oblique axial images. One-hundred and eight knees in 75 patients were studied by MRI at 1-33 months after arthroscopic ACL reconstructions using double-looped, autogenous semitendinosus and/or gracilis tendons. Knees with poor stability were excluded from this study. The examinations were performed at 0.2T with spin echo proton density and T2-weighted oblique axial images. Appearances of grafts were mainly described on spin echo proton density images based upon time after surgery. The grafts appeared as homogeneous, low signal intensity areas in the bone tunnels at 1 month after the surgery. Ring-shaped low signal intensity areas were observed along the wall of the bone tunnels in the 2- to 3-month group. In many grafts from this group, each tendinous bundle appeared as a low signal area separated by a high signal intensity area. In all cases in the 4- to 6-month group, the thickness of the ring-shaped low signal intensity area had increased, whereas the thickness of the high signal intensity area had decreased. In almost all of the cases, the interior of the bone tunnel gradually became a homologous low signal intensity region by 7 to 12 months after the surgery. According to these results, it is suggested that the maturation of the tendon-bone interface was completed from 6 to 12 months after the ACL reconstruction.
Archives of Physical Medicine and Rehabilitation, 2004
To evaluate the actual date of the return to activity and its impact on the postsurgical stabilit... more To evaluate the actual date of the return to activity and its impact on the postsurgical stability of anterior cruciate ligament reconstruction (ACLR) using hamstring grafts. A retrospective analysis. The time of return to activity was determined by a questionnaire at 24 to 36 months after ACLRs. An orthopedic center. Fifty consecutive patients who had ACLRs using hamstring grafts 24 to 36 months earlier. Not applicable. Main outcome measure The time of return to activity from a questionnaire and serial KT-2000 data at 3, 6, 12, 18, and 24 months postsurgery. Patients were divided into 2 groups according to their KT-2000 side-to-side difference at 12, 18, and 24 months postsurgery. Group I consisted of patients whose differences were 3mm or less. Group II consisted of patients whose differences were more than 3mm. At 12 and 18 months postsurgery, significant differences were detected for the time of return to running and full-speed running. A multiple regression analysis for postsurgical stability at 24 months and the time of return to these 5 activities indicated that the time of return to full-speed running and sports activities had an effect on ACL stability. An early return to vigorous activities is not recommended in patients undergoing ACLRs with hamstring grafts.
Schwann cell basal lamina tubes serve as attractive conduits for regeneration of peripheral nerve... more Schwann cell basal lamina tubes serve as attractive conduits for regeneration of peripheral nerve axons. In the present study, by using basal lamina tubes prepared by in situ freeze-treatment of rat saphenous nerve, the effects of exogenously applied basic fibroblast growth factor (bFGF) on peripheral nerve regeneration was examined 2 and 5 days after bFGF administration. Regenerating axons were observed by light and electron microscopy using PGP9.5-immunohistochemistry for specific staining of axons. In addition, the localizations of bFGF and its receptor (FGF receptor-1) were examined by immunohistochemistry using anti-bFGF antibody and anti-FGF receptor-1 antibody, respectively. Regenerating axons extended further in the bFGF-administered segment than in the bFGF-untreated control segment. Electron microscopy showed that regenerating axons grew out unaccompanied by Schwann cells. Findings concerning angiogenesis and Schwann cell migration were very similar between the bFGF treate...
The aim of this study was to examine the effects of prelesioned peripheral nerve grafts on centra... more The aim of this study was to examine the effects of prelesioned peripheral nerve grafts on central nerve regeneration compared with the freshly transected peripheral nerve grafts in the dorsal funiculus of the rat spinal cord. The experimental paradigm consisted of ligating the common peroneal nerve at the midthigh level for 7 days, while the adjacent tibial nerve was left intact. Numerous Schwann cells appeared accompanying regenerating axons in the proximal stump of the ligated nerve. The proximal stumps of the ligated (prelesioned) common peroneal nerve and the intact (untreated) tibial nerve were excised as one tissue block and autografted into the dorsal funiculi of the upper cervical cord. The graft was placed so that the prelesioned common peroneal nerve was positioned on the left dorsal funiculus and the untreated tibial nerve was positioned to the right of the midsagittal plane. Nerve regeneration was examined by light and transmission electron microscopy 1 to 16 weeks after grafting, comparing the effectiveness of prelesioned and untreated nerve grafts. Numerous regenerating axons were observed in the caudal border of both grafts 1 to 2 weeks after grafting. Astrocyte proliferation was suppressed in the prelesioned grafts compared to the untreated grafts. Four to 16 weeks later, the number of regenerating axons was approximately 10-fold as large in the prelesioned grafts as in the untreated grafts. The regenerating axons were myelinated by Schwann cells. Astrocytic glial scar formation was inconspicuous in the prelesioned grafts, whereas it was prominent in the untreated grafts. Schwann cells were contiguous with astrocytes along regenerating axons, forming a continuous conduit from the central to peripheral nerve microenvironments for the outgrowth of regenerating axons. The prelesioned peripheral nerve graft is more effective than the untreated graft in suppressing astrocytic scar formation and in supporting the outgrowth of regenerating axons in the dorsal funiculus of rat spinal cord.
Traumatic degeneration of myelinated fibers was studied by electron microscopy over 5 days follow... more Traumatic degeneration of myelinated fibers was studied by electron microscopy over 5 days following transection of mouse sciatic nerve. Special attention was paid to the mechanism which separates the degenerating part, while preserving the viable part of the axon. Immediately after transection, the opened end of the proximal stump revealed extensive subcellular changes including the disorganization of neurofilaments, and disruption of mitochondria and axonal endoplasmic reticulum (SER). Subsequently, vesicles of round and tubular profiles filled up the whole area of the stump end, and proximal to it appeared a neurofilament-predominant area characterized by randomly oriented neurofilaments and normally appearing mitochondria and SER. Characteristic membranous demarcations occurred in early periods at the border between the vesicle accumulation and the neurofilament-predominant areas, and later also within these areas. The demarcation membranes formed both by invagination of the surface plasma membrane and, probably, by fusion of the large vesicles. These became prominent with time, dividing the axoplasm into compartments of varying sizes, which gradually underwent degeneration and were liberated from the parent axon. Occurrence of autophagic vacuoles was characteristic of the degenerating portions of the parent axon. Thus, by the function of demarcation membranes, the parent axon to be preserved could remain membrane-bound, while the degenerating parts were shed off.
Uploads
Papers by Eisaku Fujimoto