Forty milliliters of venous blood were withdrawn by venous puncture from an antecubital vein 20–30 min before surgery and administration of anesthesia. Blood was collected on 5-mL tubes containing 3.8% (w/v) trisodium citrate, then centrifuged at 1800 rpm for 8 min (PRGF System II, BTI, Vitoria-Gasteiz, Spain). The 0.25-mL fractions located immediately above the erythrocytes were collected from each tube and transferred to sterile tubes. Fifty microliters of CaCl2 at 10% (w/v) were added per 1-mL fraction of platelet-enriched plasma. This preparation was injected (see below) with no delay to allow the self-assembling of the fibrin just in the gap between the fragment and its bed, providing a supportive scaffold during the healing process to facilitate tissue maturation.
Knee arthroscopic surgery was performed under general anesthesia and using the usual portals. After debridement of the crater with a curette, the loose chondral fragment was placed in its bed with a push rod then fixed with five 40 mm × 1.3 mm Ø biodegradable pins (Orthosorb® Resorbable Pin, De PuyACE Medical Company, Warsaw, IN) (Fig. 3). The full-thickness loose chondral fragment had no bone attached to it and was flexible. It fit perfectly in its bed after careful removal of a layer of initial scar tissue in its deep face with a shaver. Next, the knee was vacuumed, and a hole was drilled through the reattached chondral fragment with a Kirschner wire. Approximately 2.0 mL of the activated PRGF preparation (as described above) were then injected through the hole and into the area between the crater and the fixed fragment, filling up any existing mismatch between the crater and fragment and sealing the edges of the reattached fragment. Prophylactic treatment with antibiotics and antithrombotics was established after surgery.
Postoperatively, the patient was allowed to walk using elbow crutches, but he was maintained nonweight-bearing for 4 wk, wearing a knee brace with limited range of motion. Two weeks after surgery (Fig. 4), physical therapy was initiated, with range-of-motion exercises without axial loading. Weeks 4–8 after surgery were supposed to be of partial weight-bearing with elbow crutches. However, compliance with activity restriction was problematic, and by the sixth week after surgery, the subject could not be prevented from running and actively participating in games and sports in school (Fig. 5), even though he was not allowed to take part in formal soccer training. Unloaded stationary bicycling and strengthening exercises without axial loading were included in the recovery process between weeks 9 and 18 after surgery. The subject was allowed back in formal training with his teammates 18 wk after surgery (Fig. 6). At the time of writing, 38 wk after surgery, the subject was fully involved in training and competition without any recurrent symptoms.
The prognosis for healing after reattachment of a loose articular cartilage fragment is less favorable when the lesion is large (>2 cm in diameter), it does not extend into the vascularized subchondral area, and the fragment is purely articular cartilage and lacks subchondral bone (7,12,15,18,20,25). In this report, we have described our observation of enhanced articular cartilage healing, which led to accelerated functional recovery, by applying PRGF in a case of arthroscopically treated avulsion of articular cartilage with less favorable prognosis. The observed healing process and reattachment of the chondral body was outstanding, given that the usual operative treatment indicated for this type of lesion would have required fragment removal and crater drilling, curettage, mosaicplasty, rigid internal fixation, or autologous chondrocyte transplantation (12,25,27). Unfortunately, the long-term results of fragment excision have been described as extremely poor, even in patients treated before skeletal maturity (2), and potential disadvantages of the other operative treatments include creation of fibrocartilaginous channels, damage to the articular cartilage, donor site morbidity, and uneven articular congruence fit (12,27). The observed functional outcome was also excellent, with complete functional recovery and symptom-free resumption of normal athletic activity 18 wk after surgery. Even though this should be viewed as a preliminary report and the results cannot be unquestionably attributed to the application of PRGF based on a single case with a relatively short follow-up period, the application of PRGF could represent an interesting new technique to enhance the healing of a detached piece of articular cartilage.
Ability to repair articular knee lesions is dependent on cellularity and on the rate of matrix turnover per chondrocyte. Cell density could be enhanced considerably by local delivery of growth factors by chemotaxis and/or mitosis of local and attracted cells. Recent studies in tissue engineering have provided experimental evidence of the role of IGF-I, PDGF, TGF-β, EGF, and bFGF in chondrocyte proliferation (5,11,16,19). As cells cannot grow in an empty space, it is very important to provide a scaffold that could maintain cells adhered in the defect during the healing process. Fibrin could act as a supportive matrix and promote further tissue maturation (21). Furthermore, if this scaffold is soaked in active biological agents that are capable of inducing matrix production, such as growth factors (11), all these favorable circumstances taken together may potentially enhance the regeneration of cartilaginous tissue. In vitro studies show that three-dimensional systems are required for chondrocyte function and that interaction of the cell with its surrounding environment has a major effect in cell metabolism (13,24). In this respect, the fibrin scaffold soaked with a physiologically designed combination of growth factors may interact with the local cells and other cells attracted by chemotaxis and control cell repair mechanisms.
Consequently, to take advantage of the repair and regenerative potential of these substances, we have associated the use of growth factors and arthroscopic surgery to treat this large avulsion of articular cartilage with less favorable prognosis. This novel strategy consists of using the autologous fibrin as a three-dimensional carrier of growth factors and adhesive proteins contained in platelets. We have designed a simple and reproducible protocol to provide a natural source of growth factors that are greatly involved in repair processes. The PRGF preparation is easily obtained and manipulated, and the only concern is that once activated with calcium chloride it must be applied without delay to allow “in situ” self-assembling of the fibrin net and preservation of growth factor activity (3). In addition to a high concentration of growth factors, this preparation exhibits no antigenic capacity and preserves the integrity of platelets, which release the contents of alpha granules after activation of the concentrate (4).
In conclusion, the new application of PRGF-assisted regenerative technique could have contributed to enhance and accelerate articular cartilage healing after arthroscopic treatment of a large, nontraumatic avulsion of knee articular cartilage in an adolescent soccer player. This PRGF therapy is easy to implement, requires only about 40 mL of autologous blood, and the risk of disease transmission or antigenic reaction is nonexistent as autologous blood is not mixed with any other component of animal or human origin. Even though the present preliminary results need to be confirmed in a large cohort of patients, this PRGF-assisted tissue regeneration technique opens new perspectives in the area of human tissue regeneration and could become a valuable tool to treat a wide range of musculoskeletal injuries. Refinement of the PRGF technique and its further clinical applications as a potential stimulator in tissue repair are at present being evaluated by the authors.
1. Aichroth, P. Osteochondritis dissecans of the knee: a clinical survey. J. Bone Joint Surg. 53: 440–447, 1971.
2. Anderson, A. F., and M. J. Pagnani. Osteochondritis dissecans of the femoral condyles: long-term results of excision of the fragment. Am. J. Sports Med. 25: 830–834, 1997.
3. Anitua, E. Plasma rich in growth factors: preliminary results of use in the preparation of future sites for implants. Int. J. Oral Maxillofac. Implants 14: 529–535, 1999.
4. Anitua, E. The use of plasma-rich growth factors (PRGF) in oral surgery. Pract. Proced. Aesthet. Dent. 13: 487–493, 2001.
5. Benz, K., S. Breit, M. Lukoschek, H. Mau, and W. Richter. Molecular analysis of expansion, differentiation and growth factor treatment of human chondrocytes identifies differentiation markers and growth related genes. Biochem. Biophys. Res. Commun. 293: 284–292, 2002.
6. Buckwalter, J. A., and H. J. Mankin. Articular cartilage: tissue design and chondrocyte-matrix interaction. Instr. Course Lect. 47: 477–486, 1998.
7. Buckwalter, J. A., and H. J. Mankin. Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation. Instr. Course Lect. 47: 487–504, 1998.
8. Cahill, B. R. Osteochondritis dissecans of the knee: treatment of juvenile and adult form. J. Am. Acad. Orthop. Surg. 3: 237–247, 1995.
9. Frenkel, S. R., P. B. Saadeh, B. J. Mehrara, et al. Transforming growth factor beta superfamily members: role in cartilage modeling. Plast. Reconstr. Surg. 105: 980–990, 2000.
10. Hiraki, Y., C. Shukunami, K. Iyama, and H. Mizuta. Differentiation of chondrogenic precursor cells during the regeneration of articular cartilage. Osteoarth. Cartil. 9: S102–S108, 2001.
11. Jakob, M., O. Demarteau, D. Schafer, et al. Specific growth factors during the expansion and redifferentiation of adult human articular chondrocytes enhance chondrogenesis and cartilaginous tissue formation in vitro. J. Cell Biochem. 81: 368–377, 2001.
12. Kocher, M. S., L. J. Micheli, M. Yaniv, D. Zurakowski, A. Ames, and A. A. Adrignolo. Functional and radiographic outcome of juvenile osteochondritis dissecans of the knee treated with transarticular arthroscopic drilling. Am. J. Sports Med. 29: 562–566, 2001.
13. Larson, C. M., S. S. Kelley, A. D. Blackwood, A. J. Banes, and G. M. Lee. Retention of the native chondrocyte pericellular matrix results in significantly improved matrix production. Matrix Biol. 21: 349–359, 2002.
14. Lee, K. H., S. U. Song, T. S. Hwang, et al. Regeneration of hyaline cartilage by cell-mediated gene therapy using transforming growth factor beta 1-producing fibroblasts. Hum. Gene Ther. 12: 1805–1813, 2001.
15. Maletius, W., and M. Lundberg. Refixation of large chondral fragments on the weight-bearing area of the knee joint: a report of two cases. Arthroscopy 10: 630–633, 1994.
16. Martin, I., R. Suetterlin, W. Baschong, M. Heberer, G. Vunjak-Novakovic, and L. E. Freed. Enhanced cartilage tissue engineering by sequential exposure of chondrocytes to FGF-2 during 2-D expansion and BMP-2 during 3-D cultivation. J. Cell Biochem. 83: 121–8, 2001.
17. Martinek, V., F. H. Fu, and J. Huard. Gene therapy and tissue engineering in sports medicine. Phys. Sports Med. 28: 34–51, 2000.
18. Martinek, V., F. H. Fu, C. W. Lee, and J. Huard. Treatment of osteochondral injuries: genetic engineering. Clin. Sports Med. 20: 403–416, 2001.
19. Okazaki, R., A. Sakai, Y. Uezono, et al. Sequential changes of transforming growth factor (TGF)-beta1 concentration in synovial fluid and mRNA expression of TGF-beta1 receptors in chondrocytes after immobilization of rabbit knees. J. Bone Miner. Metab. 19: 228–35, 2001.
20. Paletta, G. A. Jr., P. A. Bednarz, C. L. Stanitski, G. A. Sandman, D. F. Stanitski, and S. Kottamasu. The prognostic value of quantitative bone scan in knee osteochondritis dissecans: a preliminary experience. Am. J. Sports Med. 26: 7–14, 1998.
21. Perka, C., U. Arnold, R. S. Spitzer, and K. Lindenhayn. The use of fibrin beads for tissue engineering and subsequential transplantation. Tissue Eng. 7: 359–361, 2001.
22. Peters, T. A., and I. D. Mclean. Osteochondritis dissecans of the patellofemoral joint. Am. J. Sports Med. 28: 63–67, 2000.
23. Sánchez, M., J. Azofra, B. Aizpurúa, R. Elorriaga, E. Anitua, and I. Andía. Use of autologous plasma rich in growth factors in arthroscopic surgery (article in Spanish). Cuader. Artroscopia 10: 12–19, 2003.
24. Schnabel, M., S. Marlovits, G. Eckhoff, et al. Dedifferentiation-associated changes in morphology and gene expression in primary human articular chondrocytes in cell culture. Osteoarthr. Cartil. 10: 62–70, 2002.
25. Strobel, M. J. Manual of Arthroscopic Surgery. Berlin: Springer-Verlag, 2002, pp. 297–330.
26. Van Der Berg, W. B., P. M. Van Der Kraan, A. Scharstuhl, and H. M. van Beuningen. Growth factors and cartilage repair. Clin. Orthop. 391: S244–S250, 2001.
27. Yoshizumi, Y., T. Sugita, T. Kawamata, M. Ohnuma, and S. Maeda. Cylindrical osteochondral graft for osteochondritis dissecans of the knee. Am. J. Sports Med. 30: 441–445, 2002.