Healing Of Tears Research Articles

Healing of full-thickness tears of avian supracoracoid tendons: in situ hybridization of α1(I) and α1(III) procollagen mRNA

Although clinically significant, much remains unknown about the healing of the torn rotator cuff tendon, because of unavailability of appropriate animal model. The human supraspinatus tendon faces the subacromial bursa superiorly, and the joint capsule inferiorly, while the digital flexor tendon is surrounded by the synovium. We hypothesized that the supraspinatus tendon heals by the process which is different from that observed with digital flexor tendons, in which epitenon cells migrate into the torn portion circumferentially. The avian supracoracoid tendon was adopted for this experiment because of its similarity to the human supraspinatus tendon. We developed a full-thickness tendon laceration followed by primary suture. The objective of this study was to detect localization of the responsible cells for repair of the tendon. We examined the process using histology and in situ hybridization. Starting at week 1, the peritendon cells of the bursal side proliferated and migrated into the laceration site. At week 6, the tendon stumps were continuous with new connective tissue. High-level expression of procollagen mRNA in the proliferating peritendon cells on the bursal side demonstrates to contribute to the reparative process, which progressed to the joint side. This mode of repair is different from that of the digital flexor tendon.

A light and electron microscopic study of ectopic tendon and ligament formation induced by bone morphogenetic protein-13 adenoviral gene therapy.

Bone morphogenetic proteins (BMPs) are involved in the growth and development of many tissues, but it is their role in skeletal development and their unique ability to induce ectopic and orthotopic osteogenesis that have attracted the greatest interest. Expression of the BMP-13 gene is predominantly localized to hypertrophic chondrocytes in regions of endochondral bone formation during development, as well as in mature articular cartilage in the adult. In addition, the application of BMP-13 on a collagen carrier induces neotendon/neoligament formation when delivered subcutaneously or intramuscularly in rodents. The aim of the present study was to determine the histological and ultrastructural changes that occur after the intramuscular injection of a first-generation BMP-13 adenoviral vector. Athymic nude rats were injected with 3.75 x 10(10) plaque-forming units of adenovirus (Ad)-BMP-13 or Ad-beta-galactosidase in the thigh musculature, and the region was examined using light and electron microscopy at various time points between 2 days and 100 days postinjection. As early as 2 days after injection of Ad-BMP-13, progenitor cells were observed infiltrating between the transduced muscle fibers. These cells subsequently proliferated, differentiated, and secreted large amounts of collagenous extracellular matrix. By 100 days postinjection, the treated tissue displayed the histological and ultrastructural appearance of neotendon/neoligament, which was clearly demarcated from the surrounding muscle. Small foci of bone and fibrocartilage were also seen within the treated tissue. A short-term bromodeoxyuridine study also demonstrated rapid mesenchymal cell proliferation at the Ad-BMP-13 injection site as early as 48 hours postinjection. At all time points, the control AD-beta-gal injection sites were found to contain only normal muscle, without evidence of inflammation or mesenchymal cell proliferation. The results of this study indicate that in the future the use of the BMP-13 gene may have therapeutic utility for the healing of tendon and ligament tears and avulsion injuries.

Vascular response of the meniscus to injury: effects of immobilization

Failed meniscal healing may lead to degenerative osteoarthritis of the knee. Healing is thought to be dependent upon an adequate blood supply, yet “normal” vascular changes during healing are not well understood. In this study we have quantified vasoactive and angiogenic responses to medial meniscal injury in a rabbit model under clinically relevant conditions, and related these to histological criteria of healing. Twenty-six adult rabbits were given a standardized meniscal injury; 12 of these had the hind limb immobilized by pinning. Eight normal controls and 12 sham-operated animals were also studied. After 4 weeks, animals underwent either vascular volume (vascular index) determination, or blood flow measurement using coloured microspheres. Histological analysis was also performed to assess meniscal healing. In injured animals, blood flow to the menisci was increased fivefold 4 weeks post-operative; this increase was prevented by immobilization. The vascular index of the menisci was also increased threefold by injury, but not significantly reduced by immobilization. Histological examination of injured menisci showed examples of healing and non-healing tears in both mobile and immobile groups. Meniscal injuries are associated with characteristic changes in vascularity and perfusion, and these changes likely play a significant role in the healing process. Characterization of the vascular responses to meniscal injury may lead to techniques that can promote reliable healing of meniscal tears and thereby improve clinical outcomes.

A light and electron microscopic study of ectopic tendon and ligament formation induced by bone morphogenetic protein–13 adenoviral gene therapy

Object Bone morphogenetic proteins (BMPs) are involved in the growth and development of many tissues, but it is their role in skeletal development and their unique ability to induce ectopic and orthotopic osteogenesis that has attracted the greatest interest. Expression of the BMP-13 gene has been shown to be predominantly localized to hypertrophic chondrocytes in regions of endochondral bone formation during development, as well as in mature articular cartilage in the adult. In addition, the application of BMP-13 on a collagen carrier induces neotendon/ligament formation when delivered subcutaneously or intramuscularly in rodents. The aim of the present study was to determine the histological and ultrastructural changes that occur after the intramuscular injection of a first-generation BMP-13 adenoviral vector. Methods Athymic nude rats were injected with 3.75 × 1010 plaque-forming unit adenovirus (Ad)-BMP-13 or Ad-β-galactosidase in the thigh musculature, and the regions examined using light and electron microscopy at various time points between 2 and 100 days postinjection. As early as 2 days after injection of Ad-BMP-13, progenitor cells were observed infiltrating between the transduced muscle fibers. These cells subsequently proliferated, differentiated, and secreted large amounts of collagenous extracellular matrix. By 100 days postinjection, the induced tissue had the histological and ultrastructural appearance of neotendon/ligament, which was clearly demarcated from the surrounding muscle. Small foci of bone and fibrocartilage were also seen within the induced tissue. A short-term bromodeoxyuri-dine study also demonstrated rapid mesenchymal cell proliferation at the Ad-BMP-13 injection site as early as 48 hours postinjection. Conclusions The results of this study suggest that in the future the use of the BMP-13 gene may have therapeutic utility for the healing of tendon and ligament tears and avulsion injuries.

Arthroscopic meniscus repair and preliminary (average 30 months) results

Arthroscopic meniscal repairs were applied to the 20 patients having peripheral (meniscocapsular junction or 3mm. peripheral) meniscus tears which were instable, vertical longitudinal and longer than 1 cm in length between 1993 and 1996. 16 patients were male and 4 patients were female. Mean age was 26.6 years (range; 17 to 40 years). Arthroscopic repair was applied to the right knees in 13 patients and to the left knees in 7 patients. There were 11 medial meniscal tears and 9 lateral meniscal tears in patients who were applied arthroscopic repair. As arthroscopic meniscal techniques in 2 cases were used. There were anterior cruciate ligament rupture in 4 cases. Two were reconstructed and other two were treated conservatively since patients did not accepted the surgery. Average follow-up was 30 months (range; 13 to 51 months). Patients were evaluated according to the Modified Marshall Knee Scoring System (MMKS) and the mean MMKS was 28. 65 (excellent). There were no pain and mechanical symptoms in the follow-ups of the patient. There were stiffness of knee joint of two patients postoperatively because of prolonged immobilization. Full range of motions were obtained after arthroscopic release, manipulation under anesthesia and aggressive rehabilitation. There were no stiffness in other cases who were applied short term immobilization and early motion. A patient had pain around the region where infrapatellar branch of safenous nerve located. This pain resolved completely in 6 months. All patients returned to the previous sportive activity level in 4 months. In this study, we observed the healing of meniscal tears which were in peripheral vascular region and having undamaged meniscus. We believe that the aim of knee surgery should be to preserve and repair the menisci.

Partially accelerated rehabilitation program after meniscal repair

Arthroscopic meniscal repairs were applied to the 20 patients having peripheral (meniscocapsular junction or 3mm. peripheral) meniscus tears which were instable, vertical longitudinal and longer than 1 cm in length between 1993 and 1996. 16 patients were male and 4 patients were female. Mean age was 26.6 years (ranges; 17 to 40 years). Arthroscopic repair were applied to the right knees in 13 patients and to the left knees in 7 patients. There were 11 medial meniscal tears and 9 lateral meniscal tears in patients who were underwent arthroscopic repair. Patient were done partially accelerated Capa rehabilitation programe postoperatively. Average follow-up was 30 months (ranges; 13 to 51 months). Patients were evaluated according to the Modified Marshall Knee Scoring System (MMKS) and the mean MMKS was 28.65 (excellent). There were no pain and mechanical symptoms in the follow-ups of the patient. There were siffness of knee joint of two patients postoperatively because of prolonged immobilization. Full range of motions were obtained after arthroscopic release, manipulation under anesthesia and aggressive rehabilitation. There were no stiffness in other cases who were applied short term immobilization and early motion. All patients whose isolated meniscal tear were repaired returned to the previous sportive activity level in average 4 months and patients underwent ACL reconstruction + meniscus repair returned to the sports in average 9 months. In this study, we observed the healing of meniscal tears which were in peripheral vascular region and having undamaged meniscus and returning of patients to the previous activity level without any problem with our rehabilitation programme.

The effect of injury on the fibro-cartilaginous meniscus

The effect of injury on the fibro-cartilaginous meniscus

Preparation of an exogenous fibrin clot

Exogenous fibrin clot has been proposed to promote the healing of meniscal tears in areas of compromised vascularity. We present a method to reproducibly prepare a tightly wound exogenous fibrin clot using 5 to 10 mL of blood obtained by sterile venipuncture. The technique produces a clot of increased consistency and high fibrin content that is adaptable in preparation as a longer, thinner clot or a shorter, thicker clot. Clots prepared in this manner will hold suture or can be morselized for extrusion through a syringe.

Does plate fixation prevent disc degeneration after a lateral anulus tear?

The sheep model was used to investigate the development of disc degeneration after outer anular tearing. The authors determined whether plate fixation promotes healing of peripheral anular tears and thereby minimizes disc degeneration. A limited outer anular tear (similar to the rim lesion) in the sheep lumbar disc causes progressive and irreversible degeneration within 6 months. Incomplete healing of the tear may result from continued movement in the vicinity of the lesion. In 15 sheep, a cut 4 x 10 mm was made in the lateral anulus of two nonadjacent lumbar discs, and a metal plate was fixed across one. Three sheep were killed immediately, and the remainder were killed after 6 months for histologic examination. There were no significant differences in propagation of the cut through the inner anulus, extent of healing, or extent of nuclear degeneration, between plated and nonplated motion segments after 6 months. Vascularization of the cartilage endplate was significantly increased on the operated side (P < 0.01), but remained unchanged on the nonoperated side. Disc degeneration was not prevented by this method of plate fixation, despite similar but limited healing of the outer anulus tear in both plated and nonplated levels.

Pathology of the Meniscus

The pathologic description of the menisci is facilitated by grouping the various disorders into etiologic groups. These include congenital anomalies, traumatic conditions, inflammatory disorders, metabolic disorders, degenerative conditions, and neoplasms. In clinical practice, traumatic conditions, as exemplified by meniscal tears of the vertical-longitudinal or vertical-transverse type, are the most important pathologic disorders. Healing of meniscal tears occurs only when the tear involves the peripheral vascularized attachment of either the lateral or medial meniscus. Intensive clinical and animal experimentation suggests that serum-derived growth factors are necessary for meniscal healing. Chondrocalcinosis is extremely frequent in the menisci of older individuals and may or may not be associated with degenerative changes of the menisci, including fibrillation, loss of protein polysaccharide ground substance, and chondrocytic proliferation. The role of degenerative changes of the menisci, including tears of the horizontal type, in the development of osteoarthritis (OA) of the knee is a subject of intense interest, as is the relationship between chondrocalcinosis and OA. Neoplastic involvement of the menisci is essentially limited to invasion by tumors starting in or, more commonly, adjacent to the knee joints.

Experimental models to promote healing of tears in the avascular segment of canine knee menisci.

Longitudinal tears were created in canine lateral menisci and techniques were applied to induce healing by removal of a core of tissue from the periphery of the meniscus to the tear or by implantation of a vascularized synovial flap into the tear. The meniscal tears did not heal in knees that were not immobilized, and they healed poorly and sporadically in knees that were immobilized in a cast but bore some weight. However, a higher percentage of tears that were treated by the core-removal or synovial-flap technique healed when the knee was firmly immobilized and weight-bearing was prevented by the use of an external skeletal fixator across the joint for eight to twelve weeks. Neovascularization and access to a source of reparative cells appear to be important in the healing process.

Healing of tears in the avascular region of sheep menisci: M. Nakhostine, D. H. Gershuni, D. R. Anderson, L. A. Danzig, G. M. Weiner, and S. Dobbs-Soanes. San Diego, California, U.S.A.

Healing of tears in the avascular region of sheep menisci: M. Nakhostine, D. H. Gershuni, D. R. Anderson, L. A. Danzig, G. M. Weiner, and S. Dobbs-Soanes. San Diego, California, U.S.A.

The arthroscopic meniscal repair. Techniques and clinical experience.

Conservative meniscal repair should limit resection to only pathologic portions of the meniscus. The periphery of the meniscus is well vascularized, enabling healing of longitudinal tears. Sutures that perforate the meniscus vertically usually lead to stable healing. In arthroscopic meniscal surgery, isolated tears are sutured from within the joint, usually using techniques related to specially developed instrumentation. Our system uses three curved cannulas of various radii and a specific needle of 1.2 mm thickness, and can be operated by one hand while the joint is distracted with an AO/ASIF femoral distractor. In our series of 54 arthroscopic meniscal repairs, 42 (78%) healed without reinjury. Retears occurred in 12 patients, and were refixed again using the same techniques. Our experience has led us to conclude that the type of meniscal tear most suitable for arthroscopic repair is a vertical longitudinal lesion that involves the vascularized zone; abrading the synovial surfaces is helpful, as is positioning the sutures tightly together; the repair should be checked at 4 months by arthroscopy or by arthrogram; and a combination of nonabsorbable and resorbable sutures is most satisfactory. We believe that with experience arthroscopic meniscal repair becomes a less involved procedure than open repair, and that in the future such repair will be successfully extended to the more centrally located lesions.

Vascularity for healing of meniscus repairs

Vascularity in the human meniscus is poor beyond 1-2 mm from the meniscosynovial junction, yet 22% of the tears in this series occur with a greater than or equal to 3-mm peripheral white rim. It is possible to suture these tears with the wider peripheral white rims, but healing rates are reduced because it is more difficult to obtain a satisfactory vascular supply. This article describes the history of our efforts at obtaining blood supply for healing of meniscus tears with a peripheral white rim up to 5 mm. Resection of the peripheral white rim to the vascular bed was unsatisfactory because it reduced the size of the meniscus and, by 3 years, the subsequent degenerative changes in the knee were comparable to meniscectomy. Holes made in the rim with a biopsy needle were again unsuccessful at improving healing. The present technique involves using rasps to abrade the parameniscal synovium on both the superior and inferior surface of the peripheral white rim. None of the peripheral white rim is resected. In the first series of 240 patients in whom peripheral white rim resection or the biopsy punch was used, the failure rate of meniscus healing was 22%. In a subsequent series of 68 patients (52 males, 16 females) who had 81 meniscal repairs by means of the rasp for parameniscal synovial abrasion, the failure rate was 9%. The rasp appears to be the safest and most effective method to gain vascularity for healing of meniscus repairs. It is possible to obtain healing with 5-mm peripheral white rims without resection of any portion of this rim, thus maintaining the full size of the meniscus.

Modified Caslicks's procedure for closure of the dorsal vulva in the cow

A cyanoacrylate tissue adhesive (Nexaband) was used to assist healing of vaginal tears, sutured a month after calving. The procedure prevented pneumovagina. Use of the adhesive overcame faecal contamination of the wound.