Morphological analysis of the femoral trochlea in patients with recurrent dislocation of the patella using three-dimensional computer models.

We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models. There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage. The mean extent of convexity was 24.9 degrees sd 6.7 degrees for patients and 11.9 degrees sd 3.6 degrees for the control group (p < 0.001). The mean height of the articular cartilage was 91.3 degrees sd 8.3 degrees for the patients and 83.3 degrees sd 7.7 degrees for the control group (p = 0.03), suggesting a wider convex trochlea in the patients with recurrent dislocation of the patella caused by the proximally-extended convex area. The lateral border of the articular cartilage of the trochlea in the patients was more laterally located than in the control group. Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects.

In vivo movement analysis of the patella using a three-dimensional computer model.

We used three-dimensional movement analysis by computer modelling of knee flexion from 0 degrees to 50 degrees in 14 knees in 12 patients with recurrent patellar dislocation and in 15 knees in ten normal control subjects to compare the in vivo three-dimensional movement of the patella. Flexion, tilt and spin of the patella were described in terms of rotation angles from 0 degrees . The location of the patella and the tibial tubercle were evaluated using parameters expressed as percentage patellar shift and percentage tubercle shift. Patellar inclination to the femur was also measured and patellofemoral contact was qualitatively and quantitatively analysed. The patients had greater values of spin from 20 degrees to 50 degrees , while there were no statistically significant differences in flexion and tilt. The patients also had greater percentage patellar shift from 0 degrees to 50 degrees , percentage tubercle shift at 0 degrees and 10 degrees and patellar inclination from 0 degrees to 50 degrees with a smaller oval-shaped contact area from 20 degrees to 50 degrees moving downwards on the lateral facet. Patellar movement analysis using a three-dimensional computer model is useful to clearly demonstrate differences between patients with recurrent dislocation of the patella and normal control subjects.

Conservative treatment for rugby football players with an acute isolated posterior cruciate ligament injury.

We investigated the outcome of the conservative treatment from the point of athletic performance for rugby football players with an acute isolated PCL injury. The subjects were sixteen competitive rugby football players, with an average age of 21 years. After exercise consisting of quadriceps muscle strengthening and range of knee motion, the players were allowed to return to sports activity when swelling and pain disappeared. At one year after the injury, the period of return to pre-injury level and the self-evaluation for eleven performances during rugby football were surveyed by a questionnaire. Each performance of the athletic skills was rated as normal, nearly normal, abnormal or severely abnormal. Fourteen players (88%) returned to their pre-injury level. The time to return to pre-injury level ranged from one to seven months, with a mean of three months. High-speed running was the most affected skill (9 out of 14, 64%). These results showed that performance of athletic skills was apparently affected in rugby football players with an acute isolated PCL injury though the conservative treatment was effective

Comparison between the cross-sectional area of bone-patellar tendon-bone grafts and multistranded hamstring tendon grafts obtained from the same patients.

This study intraoperatively compared the cross-sectional area (CSA) and graft-tunnel fit of bone-patellar tendon-bone (BTB) and multistranded hamstring tendon (STG) grafts harvested from the same patient. Twenty-two patients with a mean age of 26 years were the subjects of the study. Each BTB graft was harvested from the central third of the patellar tendon. Tripled or quadrupled semitendinosus tendon with or without gracilis tendon was used as a STG graft. CSAs of both grafts in the same patients were intraoperatively measured using a custom-made area micrometer during primary ACL reconstruction and revision surgery or during combined ACL and PCL reconstruction. Graft-tunnel fit was calculated by dividing the CSA of the graft by that of the tibial bone tunnel. The average CSA of STG grafts was significantly greater than that of BTB grafts. The average value of graft-tunnel fit for the STG grafts% was also greater than that of the BTB grafts%. Thus STG grafts have a larger CSA and closer graft-tunnel fit than BTB grafts in a clinical setting.

Endoscopic reconstruction of the anterior cruciate ligament with quadrupled hamstring tendons. A correlation between MRI changes and restored stability of the knee.

A total of 30 patients who underwent endoscopic reconstruction of the anterior cruciate ligament using quadrupled hamstring tendons, through a single drill hole in the femur, had MRI 24 to 28 months after operation. In 18 patients the scans revealed that both the anterior and posterior portions of the graft ran in parallel from the inside of the femoral to the tibial tunnel. In 12, the posterior bundle had moved anteriorly and the anterior bundle could not be identified at the anterodistal border of the femoral tunnel. The mean difference in the anterior laxity, when compared with the contralateral knee, was 2.0+/-1.7 mm and 4.3+/-2.8 mm for the two types, respectively. Damage to the anterior bundle may occur when using the endoscopic technique because of biomechanical disadvantages, including concentration of loading and repetitive bending stress in the anterior bundle at the opening of the femoral tunnel.

[Bone marrow plays an important role in joint destruction in patients with rheumatoid arthritis].

In iliac bone marrow the absolute number of mononuclear cells (MNCs) was increased in RA patients compared with the non-RA controls. In CD8 positive cell and myeloid cell fractions, significant differences were recognized between RA patients and non-RA controls. The presence of abnormal myeloid lineage cells in epiphyseal bone marrow adjacent to joints affected with severe RA was shown. Stroma cell lines from RA bone marrow with nursing activity were established and shown to play a pivotal role in the pathogenesis in RA bone marrow. Histologic study also shows that subchondral region expressing tissue-damaging proteinases plays an important role in joint destruction in RA.

Nonunited avulsion fractures of the intercondylar eminence of the tibia.

We report 3 cases of nonunited avulsion fracture of the intercondylar eminence of the tibia. Characteristics of the clinical symptoms were limitation of knee extension, pain at knee extension, and a small amount of anterior instability. For the patient with a normal anterior cruciate ligament (ACL), the fragment was fixed by sutures with a button after curettage of the fibrous tissue. Two patients underwent endoscopic ACL reconstruction using quadrupled semitendinosus tendon because their ACLs had degenerated. Since the technique of ACL reconstruction under arthroscopic control has been well refined, endoscopic ACL reconstruction is considered to be 1 of the surgical options for nonunited avulsion fracture with symptomatic anterior instability if the ACL is degenerated.

Preoperative anterior knee laxity did not influence postoperative stability restored by anterior cruciate ligament reconstruction.

Eighty-six chronic anterior cruciate ligament (ACL)-injured patients were quantitatively measured for anterior knee stability preoperatively and at 2 years or later (mean, 30 months) postoperatively to examine the influence of preoperative knee laxity on the postoperative knee stability restored by the ACL reconstruction using multiplied hamstring tendon graft. The patients were divided into 3 groups according to the preoperative injured minus normal anterior laxity difference (AL-D) (group I [n = 27] <5 mm, group II [n = 48] 5 to 9 mm, group III [n = 11] >10 mm). The 3 groups were comparable in gender, age, meniscal status, graft excursion measured during operation, time from injury to operation, and activity level. The postoperative AL-D in group I was 0.8 +/- 1. 7 mm, that in group II was 1.1 +/- 1.6 mm, and in group III was 1.5 +/- 1.4 mm. There were no significant statistical differences among these 3 groups. With our surgical technique including postoperative rehabilitation, patients with severe instability could be treated successfully without needing any additional procedures such as extra-articular augmentation or specially designed postoperative rehabilitation programs.

Chondral injury associated with acute isolated posterior cruciate ligament injury.

SUMMARY: To evaluate associated cartilaginous damage with acute isolated posterior cruciate ligament (PCL) injury without other concomitant ligamentous injury, arthroscopic evaluations were performed on 61 consecutive patients. Meniscal tear was found in 17 cases (28%). Of these, 3 had medial meniscal tear, 11 had lateral meniscal tear, and 3 had both medial and lateral meniscal tears. Longitudinal tears of anterior segment in lateral menisci were the most common (10 cases). Thirty-two patients (52%) had articular cartilage injury. Of these, 7 had damage greater than one half of the thickness of the articular cartilage, and 3 had erosion that extended to the subchondral bone. The most frequently injured location was the medial femoral condyle (19 cases, 31%). Significant cartilaginous injury could be combined in acute isolated PCL injury. Therefore, it is unreasonable to manage every acute isolated PCL-injured knee using a single treatment modality. Concomitant meniscal and articular cartilaginous lesions should be evaluated when treatment for acute PCL injury is planned.

Knee dislocation following anterior cruciate ligament disruption without any other ligament tears.

We report a rare case of complete knee dislocation following anterior cruciate ligament (ACL) disruption without any other ligament tears. The pathology of the knee joint was torn ACL, intact other ligaments, osteochondral fractures and bone bruise of the lateral femoral condyle, and torn lateral meniscus. In this case, osteochondral fracture resulting from the anteriorly sublaxiation of the tibia following ACL disruption was considered to prevent from spontaneous reduction. This case suggests that anterolateral knee dislocation and spontaneous reduction may occur in ACL injuries.

Osteoclastogenesis in iliac bone marrow of patients with rheumatoid arthritis.

OBJECTIVE: To investigate osteoclastogenesis in bone marrow cells from patients with various pathogenic backgrounds known to induce osteoporosis, to identify specific factors that may cause generalized osteoporosis in patients with rheumatoid arthritis (RA). METHODS: Bone marrow blood was obtained from 59 women, 36 with RA and 23 without RA. Patients with RA were classified as severe (26) and mild RA (10: 5 patients with and 5 without corticosteroid therapy). The non-RA subjects were divided into 3 groups, premenopausal (7), menopausal (8), and elderly (8). As a marker of bone resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP) concentration in the bone marrow supernatant was measured by radioimmunoassay. The bone marrow cells were cultured 14 days in the presence or absence of autologous bone marrow supernatant; then the number of tartrate resistant acid phosphatase positive multinucleated cells (TRAP positive MNC) was counted as an indicator of osteoclastogenesis. RESULTS: ICTP concentration of the bone marrow supernatant and the number of TRAP positive MNC showed remarkable enhancement in some patients with severe RA, but these features were not observed in the 3 control groups. CONCLUSION: Increased bone resorption and enhanced osteoclastogenesis were specifically observed in the iliac bone marrow of patients with RA, especially those with severe RA. These phenomena can be considered to accompany generalized osteoporosis in RA.

Effect of freeze-drying or gamma-irradiation on remodeling of tendon allograft in a rat model.

Freezing or freeze-drying and gamma-irradiation are techniques currently used for processing tendon allografts. However, it is still unknown how these processing methods affect graft remodeling. In this study, we used a rat patellar tendon transplantation model to investigate the effect of various processing methods on remodeling by quantifying loss of collagen labeled with a radioactive isotope. The grafts were divided into the following four groups according to the processing method: fresh-frozen, freeze-dried, fresh-frozen and gamma-irradiated, or freeze-dried and gamma-irradiated. The percentage of donor collagen, calculated from hydroxyproline content and radioactivity level, was used as an indicator of graft remodeling. At 2 weeks, the level of donor collagen in the fresh-frozen group was 62%; in the freeze-dried group, 59%; in the fresh-frozen and irradiated group, 57%; and in the freeze-dried and irradiated group, 44%. At 4 weeks, the percentage of donor collagen remaining in grafts decreased to 38% in the fresh-frozen group, 19% in the freeze-dried group, 27% in the fresh-frozen and irradiated group, and 12% in the freeze-dried and irradiated group. Finally, at 12 weeks, the levels were 19% in the fresh-frozen group, 20% in the freeze-dried group, 15% in the fresh-frozen and irradiated group, and 6% in the freeze-dried and irradiated group. The percentages of donor collagen in the freeze-dried and the fresh-frozen and irradiated groups were significantly lower than that in the fresh-frozen group at 4 weeks. The values for the freeze-dried and irradiated group were significantly lower than those for the fresh-frozen and irradiated group at 4 and 12 weeks. These data suggest that freeze-drying, freeze-drying followed by gamma-irradiation, and fresh-freezing followed by gamma-irradiation temporarily accelerate graft remodeling.

Remodeling of allogeneic and autogenous patellar tendon grafts in rats.

The differences in remodeling among frozen allografts, frozen autografts, and fresh autografts were investigated using a patellar tendon transplantation model in 2 different strains of rats. In this study, isografting (transplantation among the same strain inbred animals) was adopted as an autograft model. This method makes it possible to set up a frozen autograft model. Evaluation included mechanical properties determined during tensile failure tests, cross sectional area, histologic findings, and collagen fibril distribution. Recipient rats were euthanized at 4, 8, 12, and 24 weeks after transplantation (n = 5, in each group and in each period). The frozen allografts showed significantly less tensile strength than did the frozen autografts at 4 weeks, but this difference was transient and diminished by 8 weeks. The tensile strength of the fresh autografts was significantly greater than that of the frozen autografts at 8 weeks or the frozen allografts at 8 and 12 weeks. It was suggested that freeze thawing has adverse effects on the remodeling of fresh autografts in this extraarticular graft model. The cross sectional area for each type of graft at each posttransplantation period was about twice as large as that before transplantation. The collagen fibril profile of the frozen allografts was similar to that of the frozen autografts. However, the fresh autografts showed a greater number of large diameter fibrils and a lesser number of small diameter fibrils than did the other 2 frozen groups.

Avulsion fracture of the anteromedial bundle of the anterior cruciate ligament.

The avulsion fracture of the tibial attachment site of the anterior cruciate ligament is relatively rare among adults. Although partial avulsion fracture of this site is very rare, complex forces exerted on the knee joint could produce this type of fracture. We report on an adult patient with an avulsion fracture of the attachment site of anteromedial bundle of the anterior cruciate ligament associated with injuries of lateral and medial collateral ligament and fibular fracture. We speculate varus stress in a flexed knee coupled with rotation between the femur and tibia caused this type of injury.

Temporal and spatial expression of transforming growth factor-beta in the healing patellar ligament of the rat.

We investigated the temporal and spatial expression of transforming growth factor-beta in the healing patellar ligament of the rat by immunohistochemistry. The mid-portion of the medial half of the patellar ligament in 14-week-old male Wistar rats was cut transversely with a scalpel. On day 1 after ligament injury, diffuse staining for transforming growth factor-beta was observed in the extracellular matrix filling the wound, and the staining in the adjacent ligament tissue was as weak as it was in the normal ligament. On day 3, the intensity of the diffuse extracellular staining decreased, and the staining was observed in correspondence with the cellular distribution in the wound site and in the adjacent uninjured ligament tissue. On day 7, the intense staining was widely distributed over the whole length of the ligament tissue. On day 28, the staining for transforming growth factor-beta was still observed at the wound site and in the adjacent uninjured ligament tissue, where the staining was reduced in intensity but still stronger than it was in the normal ligament. On day 56, the expression of transforming growth factor-beta was still detectable at the wound site; however, in the adjacent uninjured ligament tissue, it had almost subsided to the normal level. The results of the present study suggest that ligament healing may be accompanied by extensive changes in the expression of transforming growth factor-beta over the whole length of ligament tissue.

Bone marrow stromal cells contribute to synovial cell proliferation in rats with collagen induced arthritis.

OBJECTIVE: To observe the migration of bone marrow stromal cells into the joint cavity and the contribution of such cells to synovial proliferation in rats with collagen induced arthritis (CIA). METHODS: After bone marrow stromal cells preliminarily labeled with fluorescent dye or 3H thymidine accumulated in the bone marrow of splenectomized rats by intraperitoneal injection, the migration of labeled stromal cells in rats with CIA was analyzed by liquid scintillation counting, autoradiography, and fluorography. RESULTS: In splenectomized control rats, labeled bone marrow stromal cells were mostly found in the bone marrow and not in the synovium. Over 2 weeks after immunization, labeled stromal cells were microscopically found migrating directly into the joint cavity through the area between the articular margin and the synovial insertion (the bare zone). Labeled stromal cells were mainly found in the sublining layers of proliferating synovial tissue. CONCLUSION: At the onset of CIA, bone marrow stromal cells migrated from the bone marrow into the affected joint cavity and seemed to contribute to synovial proliferation.

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.

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 aminopropeptide. 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.

Arthroscopic repair for a flap tear of the posterior horn of the lateral meniscus adjacent to its tibial insertion.

A flap tear of the posterior horn of the lateral meniscus adjacent to its tibial insertion combined with acute rupture of the anterior cruciate ligament was successfully repaired arthroscopically by a combination of advancement of the tip of the flap into a drill hole created in the tibia and an inside-out stacked suture technique using Henning instrumentation in two cases. However, the long-term function of the repaired menisci, which was reduced several millimeters in circumferential length, is still unknown.