Adem KAR, NİHAT DEMİRHAN DEMİRKIRAN, Hasan TATARİ, BORA UZUN, Fatih ERTEM

Hexagonal grafts in mosaicplasty: Biomechanical comparison of standard cylindrical and novel hexagonal grafts in calf cadaver model

Objective: Cylindrical grafts are currently used to cover defected area in mosaicplasty. However, there aresome difŞculties with cylindrical grafts, such as potential dead space between grafts and insufŞcientcoverage. Hexagonal graft (honeycomb model) was created and evaluated in this biomechanical study.Hypothesis was that harvesting grafts with hexagonal shape, which has the best volume geometrycharacteristics in nature, would be biomechanically advantageous and provide superior pull-outstrength.Methods: Total of 24 fresh calf femurs were divided into 3 equal groups. In theŞrst group, 1 cylindricaland 1 hexagonal graft were compared. Second group consisted of 3 cylindrical and 3 hexagonal grafts.Third group was designed to evaluate effect of graft depth; hexagonal graft implanted at 5 mm depth wascompared with 20-mm-deep hexagonal graft. All specimens were subjected to pull-out test. FrictionŞeldand graft surface area were also evaluated.Results: Pull-out strength comparison of 15-mm-deep triple cylindrical grafts and 15-mm-deep triplehexagonal grafts in second group revealed statistically signiŞcant difference in favor of hexagonal grafts(p< 0.05). Surface area of cylindrical graft with 9-mm diameter was calculated to be 50.27 mm2, whilehexagonal graft surface area was 55.425 mm2. Volume ratio of cylindrical and hexagonal grafts was753.98 mm3and 831.375 mm3, respectively.Conclusion: This biomechanical study demonstrated that graft geometry, especially in multiple graftapplications, is a factor that influences stability. Hexagonal grafts appear to be more stable than cylindrical grafts in multiple applications, and they may be used to cover a larger defected area.© 2017 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Buckwalter JA, Mankin HJ. Articular cartilage degeneration and osteoar- thritis, repair,regeneration and transplantation. Instr Course Lect. 1998;47: 487e504.

Kim HW, Moran ME, Salter RS. The potential for regeneration of articular cartilage in defects created by chondral shaving and subchondral abrasion. An experimental investigation in rabbits. J Bone Jt Surg Am. 1991;73:1301e1315.

Bert JM. Abrasion arthroplasty. Oper Tech Orthop. 1997;4:294e299.

Steadman JR, Rodkey WG, Singleton SB, Briggs KK. Microfracture technique for full thickness chondral defects. Oper Tech Orthop. 1997;7:300e307.

Newman AP. Articular cartilage repair. Current concepts. Am J Sports Med. 1998;26:309e324.

Garrett JC. Osteochondral allografts for reconstruction of articular defects of the knee. Instr Course Lect. 1998;47:517e522.

Brittberg M, Lindhal A, Nilsson A. Rabbit articular cartilage defects treated by autologous cultured chondrocytes. Clin Orthop. 1996;326:270e283.

Hangody L, Fules P. Autologous osteochondral mosaicplasty for the treatment of full- thickness defects of weight-bearing joints: ten years of experimental and clinical experience. J Bone Jt Surg [Am]. 2003;85-A(Suppl 2):25e32.

Hangody L, Dobos J, Bal o E, P anics G, Hangody LR, Berkes I. Clinical experiences with autologous osteochondral mosaicplasty in an athletic population a 17- year prospective multicenter study. Am J Sports Med. 2010 Jun 1;38(6): 1125e1133.

Guettler JH, Demetropoulos CK, Yang KH, Jurist KA. Osteochondral defects in the human knee: influence of defect size on cartilage rim stress and load redistribution to surrounding cartilage. J Sports Med [Am]. 2004;32:1451e1458.

Atik OS, Takka S, Satana T, Kanatli U, Bayar A, Senkoylu A. Osteokondral multipl otogreft transferi. Artroplasti ve Artroskopik Cerrahi Derg. 1996;7:1e2.

Ollat D, Lebel B, Thaunat M, Jones D, Mainard L, Dubrana F. Mosaic osteocondral transplantations in the knee joint, midterm results of the SFA multicenter study. Orthop Traumatol Surg Res. 2011;97(8):160e166.

Kord as G, Szab o JS, Hangody L. Primary stability of osteochondral grafts used in mosaicplasty. Arthrosc J Arthrosc Relat Surg. 2006;22(4):414e421.

Hurtig M, Novak K, McPherson R, et al. Osteochondral dowel transplantation for repair of focal defects in the knee: an outcome study using an ovine model. Vet Surg. 1998;27(1):5e16.

Haklar U, Tuzuner T, Uygur I, Kocaoglu B, Guven O. The effect of overlapping on the primary stability of osteochondral grafts in mosaicplasty. Knee Surg Sports Traumatol Arthrosc. 2008;16:651e654.

Kord as G, Hangody L. The effect of drill-hole length on the primary stability of osteochondral grafts in mosaicplasty. Orthopedics. 2005;28:401e404.

Whitesidea RA, Bryanta JT, Jakobb RP, Mainil-Varletc P, Wyssad UP. Short-term load bearing capacity of osteochondral autografts implanted by the mosaic- plasty technique: an in vitro porcine model. J Biomech. 2003;36:1203.

Duchow J, Hess T, Kohn D. Primary stability of press-Şt-implanted osteo- chondral grafts. Influence of graft size, repeated insertion, and harvesting technique. Am J Sports Med. 2000;28.1.

Pearce SG, Hurtig MB, Clarnette R, Kalra M, Cowan B, Miniaci A. An investi- gation of 2 techniques for optimizing joint surface congruency using multiple cylindrical osteochondral autografts. Arthroscopy. 2001;17:50e55.

Marcacci M, Kon E, Zaffagnini S, Iacono F, Neri MP, Vascellari A. Multiple osteochondral arthroscopic grafting (mosaicplasty) for cartilage defects of the knee: prospective study results at 2-year follow-up. Arthroscopy. 2005;21:462.

Coons DA, Barber FA. Arthroscopic osteochondral autografting. Orthop Clin North Am. 2005;36:447e458.

Agneskirchner JD, Brucker P, Burkart A, Imhoff AB. Large osteochondral de- fects of the femoral condyle: pressŞt transplantation of the posterior femoral condyle (MEGA-OATS). Knee Surg Sports Traumatol Arthrosc. 2002;10: 160e168.

Horas U, Pelinkovic D, Herr G, Aigner T, Schnettler R. Autologous chondrocyte implantation and osteochondral cylinder transplantation in cartilage repair of the knee joint. A prospective, comparative trial. J Bone Jt Surg [Am]. 2003;85-A: 185e192.

Chris M. Lyons - Warsaw Orthopedic, Inc. Surgical apparatus and method for manipulating one or more osteochondral plugs. Patent no: US 8394100 B2. Issued 12 Mar 2013.