The articular cartilage after osteotomy for medial gonarthrosis. Biopsies after 2 years in 19 cases.

In 19 consecutive patients with medial gonarthrosis, an arthroscopic examination with a biopsy of the load-bearing cartilage in the medial femoral condyle was undertaken at the same time as a proximal tibial osteotomy. A follow-up arthroscopic biopsy was performed on an average of 2 years after the osteotomy. In 9 knees there was an improvement in the cartilage quality, 8 knees were unchanged, whereas 2 knees had deteriorated. Radiographically, 6 knees had improved, 11 were unchanged and 2 had deteriorated. We found no correlation between cartilage improvement and the clinical and radiographic outcome. Our results confirm that an osteotomy has a beneficial effect on the load-bearing cartilage in the medial femoral condyle.     

Replacement of the medial tibial plateau by a metallic implant in a goat model

The purposes of the present study were to explore the surgical possibilities for replacement of the medial tibial plateau by a metallic implant in a large animal model and to examine the implications for the opposing cartilage. In six goats, the medial tibial plateau of the right knee was replaced by a cobalt–chromium implant, using polymethylmethacrylate bone cement for fixation. The unoperated left knee served as a control. At 26 weeks after surgery, the animals were killed, and the joints evaluated macroscopically. Cartilage quality was analyzed macroscopically and histologically. Glycosaminoglycan content, synthesis, and release were measured in tissue and medium. All animals were able to move and load the knees without any limitations. Macroscopic articular evaluation scores showed worsening 26 weeks after inserting the implant (p < 0.05). Macroscopic and histologic scores showed more cartilage degeneration of the opposing medial femoral condyle in the experimental knee compared to the control knee (p < 0.05). Higher glycosaminoglycan synthesis was measured at the medial femoral condyle cartilage in the experimental knees (p < 0.05). This study shows that the medial tibial plateau can be successfully replaced by a cobalt–chromium implant in a large animal model. However, considerable femoral cartilage degeneration of the medial femoral condyle was induced, suggesting that care must be taken introducing hemiarthroplasty devices in a human clinical setting for the treatment of postmeniscectomy cartilage degeneration of the medial tibial plateau. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:429–435, 2010     

Articular cartilage lesions of the knee

The pathogenesis and clinical significance of articular cartilage lesions of the knee persist as topics of considerable interest among orthopedic surgeons. This study was designed to assess the association of articular cartilage degeneration with concomitant intraarticular abnormalities and to correlate the prevalence and severity of articular cartilage damage with preoperative historical and physical exam findings in patients presenting with knee pain. Twenty-six history and physical exam data points were prospectively collected from 192 patients (200 knees), consecutively undergoing arthroscopic knee surgery. During surgery, all articular cartilage lesions were recorded with respect to size, location, and character and were graded according to Oglivie-Harris et al. All concomitant knee joint abnormalities were simultaneously recorded. Of 200 knees examined arthroscopically, 12 knees revealed no demonstrable etiology for the presenting symptoms, 65 knees revealed assorted intraarticular pathology but no articular cartilage degeneration, and the remaining 123 knees revealed a total of 211 articular cartilage lesions (103 femoral, 72 patellar, 36 tibial); 7 femoral, 6 patellar and 0 tibial lesions were completely isolated (no concomitant knee joint pathology). The concomitance of femoral defects with tibial lesions was highly significant (p = 0.01). Femoral and tibial articular cartilage lesions were strikingly correlated with the presence of an unstable torn meniscus (p less than 0.001). Medial compartment articular cartilage lesions were significantly more common (p = 0.001), more closely associated with meniscal derangement, and appreciably more severe than lateral compartment lesions. In 75% of anterior cruciate ligament-deficient knees with concomitant articular cartilage degeneration, the duration from injury to surgery was greater than 9 months, and in each of these cases, a history of reinjury to the knee was elicited. From these data one can conclude that: (a) in some patients with painful knees, isolated articular cartilage lesions may be the only abnormality noted at arthroscopy; (b) unstable meniscal tears are significantly associated with destruction of articular cartilage; (c) the medial compartment is particularly susceptible to articular cartilage degeneration; and (d) in our series, anterior cruciate ligament tears were increasingly associated with articular cartilage destruction as the elapsed time from injury to arthroscopy increased.     

Osteonecrosis of the knee after arthroscopic surgery for meniscal tears and chondral lesions.

PURPOSE: Avascular necrosis of the knee following arthroscopic surgery has been described. The purpose of this article is to report a large series of patients who developed avascular necrosis after arthroscopy of the knee in an effort to delineate casual factors and results of treatment. TYPE OF STUDY: Case series. METHODS AND MATERIALS: The charts, radiographs, and magnetic resonance imaging (MRI) scans of patients who developed osteonecrosis (ON) of the knee after routine arthroscopic surgery were reviewed. Only those patients with no evidence of ON on preoperative MRI performed 6 weeks or longer after symptom onset and who postoperatively developed ON confirmed by repeat MRI and/or by pathological testing (specimens obtained at subsequent total knee arthroplasty) were included in the study. Seven patients with average age of 60 years (range, 41 to 79 years) met these inclusion criteria. RESULTS: The lesions noted at arthroscopy included 4 medial meniscus tears, 3 lateral meniscal tears, 6 chondromalacia of the medial femoral condyle, 2 chondromalacia of the medial tibial plateau, 1 chondromalacia of the lateral femoral condyle, 1 chondromalacia of the lateral tibial plateau, and 2 chondromalacia of the patella. The location of postarthroscopy ON correlated geographically with pre-existing pathology. All 7 patients had meniscal and/or chondral lesions addressed surgically in the compartment that subsequently developed ON. Six of the 7 patients had an adjacent ipsilateral meniscus tear treated with partial meniscectomy (4 medial, 2 lateral). In addition, of the 4 patients who developed ON of the medial femoral condyle, all had overlying chondromalacia, 3 of whom were treated with arthroscopic chondroplasty. Of the 2 patients with lateral meniscal tears, 1 developed ON of the lateral femoral condyle and the other developed ON of the lateral tibial plateau. Three patients went on to require total knee arthroplasty, and 2 high tibial osteotomy. One patient's ON resolved and another patient was lost to follow-up. CONCLUSION: ON should be considered in patients who have worsening symptoms after arthroscopy of the knee. These findings suggest a possible relationship between arthroscopic treatment of chondral and meniscal lesions and later appearance of ON in some patients. The role of arthroscopy in the development of ON needs to be further studied. Those at risk are elderly patients with chondral and meniscus lesions.     

Arthroscopic evaluation of allograft anterior cruciate ligament reconstruction.

In a previous study, we evaluated the findings of arthroscopic second looks at open anterior cruciate ligament reconstructions using autogenous tissue. We were disappointed at the variable quality of the ligaments and the presence of articular cartilage lesions. These findings led us to change our treatment protocol. Since 1983, we have used freeze-dried allografts for arthroscopic intraarticular ACL reconstructions. We have started protected motion in a brace immediately postoperatively and delayed weightbearing for 12-16 weeks. A total of 54 patients with at least a 2-year follow-up were evaluated subjectively (Lysholm scale) and objectively (KT 1000). Some 78% were rated good or excellent, and 87% were satisfied with their surgery. Of these 54 patients, 28 underwent subsequent surgery for hardware removal, manipulation, or removal of adhesions. All 28 had an arthroscopy, and an evaluation of ligamentous tissue and articular cartilage at the time of the second surgery. The graft resembled a normal anterior cruciate ligament in 18 patients. The graft was slightly lax in two of these patients, but their clinical examination revealed normal stability. In six patients, the intercondylar notch was covered by a sheath of dense, fibrous tissue, but the knees were stable. In two cases, there was slight fraying of the lateral aspect of the graft from impingement on the lateral femoral condyle. In two cases the graft failed. The condition of the articular cartilage was documented and compared with the condition of the articular cartilage at the time of cruciate reconstruction. In 19 cases, the articular cartilage had been normal and remained normal at the time of reevaluation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Early knee mobilization after osteotomy for gonarthrosis

In a prospective study, 32 knees in 32 patients were randomized to either a cylinder plaster cast (17 knees) or hinged cast-brace (15 knees) after high tibial osteotomy for medial gonarthrosis. At 6 weeks, 3 months, and still 1 year after surgery, the range of motion was better in the cast-brace group. There was no difference in the other clinical results at 3 months and at 1 year after surgery, nor in changes of osseous correction or in the final knee alignment. All the patients in the cast-brace group were satisfied with early motion.     

Early knee mobilization after osteotomy for gonarthrosis

In a prospective study, 32 knees in 32 patients were randomized to either a cylinder plaster cast (17 knees) or hinged cast-brace (15 knees) after high tibial osteotomy for medial gonarthrosis. At 6 weeks, 3 months, and still 1 year after surgery, the range of motion was better in the cast-brace group. There was no difference in the other clinical results at 3 months and at 1 year after surgery, nor in changes of osseous correction or in the final knee alignment. All the patients in the cast-brace group were satisfied with early motion.     

Posttraumatic cartilage degradation progresses following anterior cruciate ligament reconstruction: A second-look arthroscopic evaluation

BackgroundSeveral studies have demonstrated that posttraumatic knee osteoarthritis progresses even after anterior cruciate ligament reconstruction. Few reports described zone-specific cartilaginous damages after anterior cruciate ligament reconstruction. This study aimed to compare the status of articular cartilage at anterior cruciate ligament reconstruction with that at second-look arthroscopy.MethodsThis study included 20 patients (20 knees, 10 males and 10 females, mean age 22.4 years, Body mass index 24.4 kg/m²) that underwent arthroscopic anatomic double-bundle anterior cruciate ligament reconstruction and second-look arthroscopy. Mean periods from injury to reconstruction and from reconstruction to second-look arthroscopy were 3.4 and 15.3 months, respectively. Cartilage lesions were evaluated arthroscopically in the 6 articular surfaces and 40 articular subcompartments independently, and these features were graded with the International Cartilage Repair Society articular cartilage injury classification; comparisons were made between the grades at reconstruction and at second-look arthroscopy. Furthermore, clinical outcomes were assessed at reconstruction and at second-look arthroscopy, using the Lysholm knee score, Tegner activity scale, International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, side-to-side difference of the KT-2000 arthrometer, and pivot shift test.ResultsEach compartment showed a deteriorated condition at second-look arthroscopy compared with the pre-reconstruction period. A significant worsening of the articular cartilage was noted in all compartments except the lateral tibial plateau and was also observed in the central region of the medial femoral condyle and trochlea after reconstruction. However, each clinical outcome was significantly improved postoperatively.ConclusionsGood cartilage conditions were restored in most subcompartments at second-look arthroscopy. Furthermore, posttraumatic osteoarthritic changes in the patellofemoral and medial compartments progressed even in the early postoperative period, although good knee stability and clinical outcomes were obtained. Care is necessary regarding the progression of osteoarthritis and the appearance of knee symptoms in patients undergoing anterior cruciate ligament reconstruction.     

Fibroblast growth factor 2 in synovial fluid from an osteoarthritic knee with cartilage regeneration

 The levels of fibroblast growth factor 2 (FGF2) in synovial fluid of osteoarthritic knees were measured. The correlation between FGF2 and the severity of cartilage degeneration in varus-deformed knees with medial compartmental osteoarthritis or the articular cartilage regeneration that occurs after high tibial osteotomy (HTO) were investigated. Knees that underwent total knee arthroplasty (TKA) were categorized as either mildly or severely degenerated according to a modified Outerbridge's grading system for degeneration of articular cartilage. Regeneration of articular cartilage was observed in a biopsy specimen from the medial femoral condyle removed with the patient's consent during hardware removal approximately 2 years after HTO. The joint fluid FGF2 level was measured at that time using an enzyme-linked immunosorbent assay. Cartilage regeneration was classified as immature or mature according to the staging for regeneration of articular cartilage. The histological findings were analyzed using Pineda's evaluation method for cartilage regeneration. The mean concentration of FGF2 was 57.4 ± 17.6 pg/ml in the joint fluid from knees with severely degenerated cartilage. This was higher than the FGF2 concentration found in the mildly degenerated group. Approximately 2 years after HTO the FGF2 level in synovial fluid was lower in knees with mature regenerated cartilage than in those with immature regeneration. Osteoarthritic knees at a more mature regeneration stage had a lower Pineda's histological score. This result suggested that the FGF2 concentration in knees with osteoarthritis was influenced by articular cartilage degeneration and regeneration, and it correlated with the histological evaluation. Received: September 26, 2002 / Accepted: January 20, 2003 RID="*" ID="*" Offprint requests to: K. Orito     

Osteochondral autografts transfer for post-traumatic osteochondral defect of the knee-2 to 5 years follow-up

The treatment of post-traumatic osteochondral defects of the weight-bearing surface of the knee in young active patients remains a significant challenge. We report the results of an osteochondral autograft transfer (OAT) in 18 patients (mean age 29 years) with post-traumatic focal osteochondral defects of the knee. Sixteen lesions were over the femoral condyle and two were over the tibial plateau. The average size of the lesion was 4.1 cm² (from 2.25 to 6 cm²), and the subchondral bone involved no more than 1 cm in depth. Osteochondral grafts were harvested from the non-weight-bearing area of the femoral condyle. Ten patients also had concomitant surgical procedures. The average follow-up was 42 months (from 24 to 64 months). All patients were evaluated by Lysholm and Tegner activity scores and plain radiographs. Nine patients had MRI, eight patients had second-look arthroscopy and two had a biopsy. Sixteen patients (89%) had good to excellent results, while two patients with lesion over the tibial surface had fair results. The biopsy revealed survival of hyaline cartilage. For small to medium osteochondral lesion over the femoral condyle of the knee in selected patients, osteochondral autografting yielded promising short to mid-term results.     

Articular cartilage lesions in the symptomatic anterior cruciate ligament-deficient knee

Purpose: The goal of the study was to report the prevalence of the lesions of the articular cartilage of the femoral condyles and tibial plateau in patients with a symptomatic anterior cruciate ligament (ACL)-deficient knee undergoing day-case arthroscopy. Type of Study: Case series study. Methods: We studied 378 skeletally mature patients (average age, 27.3 years; range, 16–50 years; 282 men and 84 women), part of a sample of 1,978 patients undergoing a primary knee arthroscopy between January 1986 and August 1993. The articular cartilage lesions were classified according to Outerbridge by a single observer. We assessed the relationship between time of injury and articular cartilage lesions and between meniscal lesions and articular cartilage lesions. Results: A complete ACL tear was found in all 378 knees. Of these, 157 showed at least one lesion of the articular cartilage. The medial femoral condyle (MFC) showed the highest frequency of articular cartilage lesions, especially in the weight-bearing portion. Patients with a bucket-handle tear of the medial meniscus had greater degeneration of the MFC than those with other meniscal tears. A meniscal tear was associated with a greater degree of articular damage. The second most common lesion was a combined lesion of the medial and lateral compartments, followed by isolated lateral compartment lesion. A time-dependent pattern of development of articular cartilage lesions was identified. Conclusions: In patients with more advanced degenerative changes, the time from injury to arthroscopy was significantly longer than in patients with lesser articular surface abnormalities, and the presence of a meniscal tear was associated with a greater degree of articular cartilage damage. Patients with a symptomatic ACL-deficient knee and an associated tear of the medial meniscus are at high risk of having a lesion of the articular surface of the weight bearing area of the knee.     

First successful autologous chondrocyte implantation in Pakistan

Osteochondritis dissecans entails a hyaline cartilage defect of the articular surface causing pain and functional restriction in young adults, sometimes resulting in early degenerative arthritis. Conventional treatment methods such as abrasion chondroplasty and mosaicplasty have limitations in terms of quality of the resultant cartilage and donor site morbidity. A more recent technique, autologous chondrocyte implantation (ACI) results in hyaline cartilage formation and gives good long-term outcome, but requires a high-level cell culture facility and two surgical procedures. The patient was a young female with knee pain, intermittent locking and feeling of "joint mouse". MRI scan and arthroscopy showed a 2 x 2 cm full thickness osteochondral defect in the medial femoral condyle. A free fragment of articular cartilage was found, which was extracted arthroscopically, and chondrocytes were cultured from it in the Juma laboratory. Subsequently, patient underwent surgery whereby the chondrocytes were injected under a periosteal patch sewn over the defect. Over six months, patient's symptoms completely resolved and she returned to full function. A repeat arthroscopy after one year revealed complete filling of the previous defect with normal appearing cartilage indicating success of the procedure. This technology can be utilized for treating patients with a variety of conditions affecting hyaline cartilage of joints.     

Congenital dislocation of the patella

Purpose Congenital dislocation of the patella is permanent and manually irreducible, and it manifests immediately after birth with flexion contracture of the knee, genu valgus, external tibial torsion and foot deformity. We retrospectively reviewed the results of operative treatment of seven knees in six patients with congenital dislocation of the patella. Methods The age of the six patients at diagnosis ranged from 8 days to 3.6 years, with an average of 1.3 years, and their age at the time of operation ranged from 0.6 to 3.9 years, with an average of 2.1 years. Serial casting and/or a brace was attempted before surgery in five of seven knees, leading to improvement in the flexion contracture of the knee. All knees were treated operatively in combination with lateral release, medial plication, V-Y lengthening of the quadriceps, medial transfer of the lateral patellar tendon and posterior release of the knee. Results Although these deformities were noticed at birth in all seven knees, diagnosis was delayed in three knees due to the low suspicion of the disease and invisible patellae on radiographs. Ultrasonography confirmed the diagnosis of dislocation. The patella was centered in the groove of the femoral condyle after surgery in all knees, but subluxation of the knee with flexion was observed in one knee in which the operation was performed at 3.9 years. Genu valgus and external tibial torsion improved after surgery in all knees. The operated knee was mobile in all cases, with less than 10° flexion contracture of the knee. Flexion contracture did not increase in any of the knees. Conclusion Congenital dislocation of the patella should be suspected in every patient with knee flexion contracture, genu valgus, external tibial torsion, foot deformity and delayed walking. Successful results were obtained when the operation was performed in younger children. Other procedures, such as the semitendinosus tenodesis or tendon transfer, might have to be combined to achieve better stability with flexion in older children. None of the authors received financial support for this study.     

The clinical outcomes and the ability to sit straight in the Japanese style following high tibial osteotomy combined with osteochondral autologous transfer for osteonecrosis of the medial femoral condyle

Background

There have been some reports of high tibial osteotomy combined with osteochondral autograft transfer for osteonecrosis of the medial femoral condyle of the knee. However, few of them have focused on the deep knee flexion needed to sit straight in the Japanese style.

Autoarthroplasty of knee cartilage defects by osteoperiosteal grafts

Five fresh osteochondral fractures of the knee, which could not be fixed because of extensive fragmentation, were treated by excision of the fragments and reconstruction of the joint surface defect by an autogenous osteoperiosteal graft. The procedure was also used for joint surface reconstruction in sclerotic osteochondritis of the femoral condyle (nine knees) and grave patellofemoral chondromalacia (three knees). Plaster cast immobilization for 3 weeks was used in the two early cases. In all other cases, we employed a passive motion apparatus for 2 days postoperatively, followed by active mobilization in a knee brace with extension-flexion 30 to 90 degrees (femoral condyle reconstruction) or 0 to 45 degrees (patellar reconstruction). Gradual free movements were started 3 weeks postoperatively. The results after 1.5 to 6.5 years were satisfactory in all but one case. One arthroscopic removal of the loose graft was performed, as were two arthroscopic graft margin shavings. Three other reoperations were unrelated to the osteoperiosteal reconstruction. It appears that periosteal reconstruction should be considered in local osteochondral lesions, where excision of the injured cartilage is mandatory. The results were best in fresh trauma cases and younger people.     

Pedunculated synovium grafts in articular cartilage defects in rabbits.

A rabbit model was used to assess the nature of healing tissues in hyaline cartilage defects and to compare the healing in defects treated with pedunculated synovium grafts to those in defects without synovial grafting. Both knees of 28 1-year-old rabbits were operated. A 3 x 2-mm cartilage defect that exposed cancellous bone was created in the non-weight-bearing area of each medial femoral condyle. Each right-knee defect was covered with a pedunculated synovial graft obtained from the same joint, and the left-knee defects were left uncovered as controls. Groups of rabbits were sacrificed at 3, 6, 12, and 24 weeks postsurgery. Sections from each knee were stained with hematoxylin-eosin and safranin O-fast green staining, and were immunohistochemically stained for type II collagen. The healing at each site was histologically scored, and the intensity of staining for type II collagen was graded. At 12 and 24 weeks, statistical comparisons of histological scores revealed significantly more hyaline cartilage tissue in the synovium-grafted defects. At 24 weeks, these same defects showed significantly more type II collagen. Thus, pedunculated synovium transplantation appears to hold promise as a method for repairing hyaline cartilage defects.     

High tibial osteotomy with a calibrated osteotomy guide, rigid internal fixation, and early motion. Long-term follow-up

BACKGROUND: We studied the results of sixty-four valgus-producing high tibial osteotomies performed with the use of a calibrated osteotomy cutting guide and rigid internal fixation, and followed by early motion, in fifty-six patients who had medial unicompartmental osteoarthritis and varus malalignment. Long-term studies have demonstrated that a high tibial osteotomy performed with staple fixation and followed by immobilization in a cast has an expected survival rate of approximately 85 percent at five years and 60 percent at ten years (in studies of ninety-five knees and 213 knees, respectively). To the best of our knowledge, there are no long-term reports on high tibial osteotomies performed with a calibrated osteotomy cutting guide and rigid internal fixation and followed by early motion. METHODS: The indications for high tibial osteotomy were medial unicompartmental osteoarthritis and varus malalignment. A lateral closing-wedge osteotomy was performed. The patients were reexamined to obtain a knee score, to make lateral radiographs of both knees, and to make a full-length anteroposterior radiograph (showing the entire lower extremity, including the hip and ankle) of the involved knee with the patient standing. RESULTS: Twenty-one knees were treated with a subsequent total knee arthroplasty at an average of sixty-five months after the high tibial osteotomy. The remaining forty-three knees had a good or excellent clinical result, with an average knee score of 94 points at an average of 8.5 years after the osteotomy. Survivorship analysis showed an expected rate of survival, with conversion to a total knee arthroplasty as the end point, of 85 percent at five years and 53 percent at ten years. No patient had patella baja postoperatively. There were six complications: four superficial wound infections, one superficial-vein thrombosis, and one delayed union (union occurred at five months). CONCLUSIONS: High tibial osteotomy has been criticized because of a high rate of complications, a loss of effectiveness with time, and the difficulty of conversion to a total knee arthroplasty secondary to patella baja. In our series, in which an osteotomy was performed with a calibrated osteotomy cutting guide and rigid internal fixation and was followed by early motion, the rate of complications was low and approximately two-thirds of the knees had a good or excellent clinical result at an average of 8.5 years. Conversion to a total knee arthroplasty was accomplished without difficulty in the patients who had this procedure. We highly recommend high tibial osteotomy with a calibrated osteotomy cutting guide, rigid internal fixation, and early motion for patients who wish to continue an active lifestyle.     

综合手术治疗膝关节骨性关节炎合并膝内翻

目的 为使膝关节骨性关节炎合并膝内翻的年轻患者延缓行全膝关节置换,探讨股骨内髁马赛克植骨、髌骨成形并胫骨高位截骨综合手术治疗膝关节骨性关节炎合并膝内翻的临床疗效.方法 2004年6月-2006 年2月,对8例10膝骨性关节炎合并膝内翻患者行综合手术治疗.其中男2例3膝,女6例7膝;年龄42～56岁.左膝3例,右膝3例,双膝2例.患者均表现为行走或站久后疼痛.X 线片示股胫关节及髌骨边缘骨质增生,以内侧为重,髌股关节间隙变窄或消失,膝关节内侧间隙明显变窄.股胫角185～200°,平均 190°;HSS 膝关节评分为55～75分,平均60分.膝痛1～12年,平均5年. 结果 术后切口均Ⅰ期愈合,无早期并发症发生.患者均获随访7～24个月,平均15个月.患者截骨部位均于8～11 周达临床愈合,平均9周.股胫角矫正15～30°,平均 20°,基本恢复正常负重力线,膝关节外翻角 10°.术后关节活动度为 100～120°,较术前增加 5～20°,平均增加 10°.X 线片示膝关节内翻畸形基本纠正,截骨处无移位,内固定无松动、断裂.术后6个月HSS膝关节评分75～88分,平均80分. 结论 股骨内髁马赛克植骨使关节软骨得到一定程度的修复重建,髌骨成形有效解决膝前区疼痛,胫骨高位截骨矫正异常负重力线,三者结合,疗效肯定.     

Influence of trypsin on the regeneration of hyaline articular cartilage

A purely chondral lesion was inflicted at the medial or lateral femoral condyle of the knee joints of 54 adult male rabbits in order to study hyaline cartilage regeneration. The experimental group was given a sequential intraarticular instillation of trypsin and autologous blood, the control groups were given trypsin or blood or nothing. Only the experimental group (trypsin and autologous blood) showed hyaline cartilage regeneration in 2/3 of the cases examined. Apparently neither the healthy cartilage nor the synovial membrane suffered damage from the trypsin injection.

A possible mechanism of cartilage regrowth may be the inhibition of chalones by the fermentative effect of trypsin, which stimulates the aggregation of thrombocytes and fibrin from the injected blood on the chondral lesion, thus initiating the regeneration of hyaline cartilage.     

Influence of trypsin on the regeneration of hyaline articular cartilage

A purely chondral lesion was inflicted at the medial or lateral femoral condyle of the knee joints of 54 adult male rabbits in order to study hyaline cartilage regeneration. The experimental group was given a sequential intraarticular instillation of trypsin and autologous blood, the control groups were given trypsin or blood or nothing. Only the experimental group (trypsin and autologous blood) showed hyaline cartilage regeneration in 2/3 of the cases examined. Apparently neither the healthy cartilage nor the synovial membrane suffered damage from the trypsin injection. A possible mechanism of cartilage regrowth may be the inhibition of chalones by the fermentative effect of trypsin, which stimulates the aggregation of thrombocytes and fibrin from the injected blood on the chondral lesion, thus initiating the regeneration of hyaline cartilage.