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New tissue-engineering technology was developed to create a cartilage-like tissue in a three-dimensional culture using atelocollagen gel. The minimum 2-year followup outcome of transplanting autologous chondrocytes cultured in atelocollagen gel for the treatment of full-thickness defects of cartilage in knees was reported from the single institution. The present multicenter study was conducted to determine clinical and arthroscopic outcomes in patients who underwent atelocollagen-associated autologous chondrocyte implantation for the repair of chondral defects of the knees.At six medical institutes in Japan, we prospectively evaluated the clinical and arthroscopic outcomes of transplanting autologous chondrocytes cultured in atelocollagen gel for the treatment of full-thickness defects of cartilage in 27 patients (27 knees) with cartilage lesions on a femoral condyle or on a patellar facet over 24 months.The Lysholm score significantly increased from 60.0 +/- 13.7 points to 89.8 +/- 9.5 points (P = 0.001). Concerning the ICRS grade for arthroscopic appearance, 6 knees (24%) were assessed as grade I (normal) and 17 knees (68%) as grade II (nearly normal). There were few adverse features, except for detachment of the graft in two cases.We concluded that transplanting chondrocytes in a newly formed matrix of atelocollagen gel can promote restoration of the articular cartilage of the knee.

Secondary collapse of the femoral head after transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head is a major complication leading to failure. We investigated the relation between the extent and shape of a newly established healthy weight-bearing area and the incidence of secondary collapse.Altogether, 38 hips in 32 patients with a mean age of 33 years at the time of surgery were followed for a mean of 4 years.The outcome was satisfactory in 22 hips (58%) and unsatisfactory in 16 hips (42%), with 9 requiring total hip arthroplasty. The extent of the newly established healthy weight-bearing area as depicted on the immediate postoperative radiograph was significantly greater in the satisfactory group than in the unsatisfactory group. The rate of secondary collapse was significantly higher when the newly established weight-bearing area was thin, like a beak ("beak-shaped" healthy area). The incidence of a beak-shaped healthy area was significantly higher in the steroid group than in nonsteroid group.We concluded that we should be cautious when the newly established healthy weight-bearing area exhibits this beak shape, even if its extent in the weight-bearing area is large, because of the higher risk of postoperative secondary collapse. In such cases, alteration of the after-treatment program (e.g., prolonging the non-weight-bearing period) should be considered.

Following knee ligament injury, clinical and experimental investigations usually focus on the injured ligament, and uninjured ligaments of the same joint are largely ignored and presumed to remain unchanged. The purpose of this study was to characterize changes in mRNA levels for a relevant subset of molecules in the uninjured knee ligaments following combined unilateral medial collateral ligament (MCL) and partial anterior cruciate ligament (ACL) transection in sheep. Semiquantitative reverse transcription-polymerase chain reaction was performed for collagen types I, III, and V; matrix metalloproteinase-13 (MMP-13); and tissue inhibitor of metalloproteinase-1 for both injured and uninjured knee ligaments at 6 and 12 weeks after injury. Collagen type I, III, and V mRNA levels were significantly increased in MCL scars at 6 weeks as well as in the uninjured lateral collateral ligament and the anteromedial band of the ACL (AM-ACL). MMP-13 mRNA levels were also elevated in the MCL at 6 and 12 weeks and in the AM-ACL 6 weeks after injury. In contrast, significant changes in the posterior cruciate ligament were not detected at either time point, indicating specificity in the transient alterations. These results suggest that following injury, responses occur in uninjured ligaments that are specific although transient in nature. These responses may be an adaptive attempt to preserve function until the scar tissue can stabilize the mechanical environment following injury.