Shape, loading, and motion in the bioengineering design, fabrication, and testing of personalized synovial joints

Abstract

With continued development and improvement of tissue engineering therapies for small articular lesions, increased attention is being focused on the challenge of engineering partial or whole synovial joints. Joint-scale constructs could have applications in the treatment of large areas of articular damage or in biological arthroplasty of severely degenerate joints. This review considers the roles of shape, loading and motion in synovial joint mechanobiology and their incorporation into the design, fabrication, and testing of engineered partial or whole joints. Incidence of degeneration, degree of impairment, and efficacy of current treatments are critical factors in choosing a target for joint bioengineering. The form and function of native joints may guide the design of engineered jointscale constructs with respect to size, shape, and maturity. Fabrication challenges for joint-scale engineering include controlling chemo-mechano-biological microenvironments to promote the development and growth of multiple tissues with integrated interfaces or lubricated surfaces into anatomical shapes, and joint-scale bioreactors which nurture and stimulate the tissue with loading and motion. Finally, evaluation of load-bearing and tribological properties can range from tissue to joint scale and can focus on biological structure at present or after adaptation.

Joint Cartilage Tissue Engineering and Pre-Clinical Safety and Efficacy Testing

“…Presently, focal cartilage injuries in humans are treated by abrasion arthroplasty with or without subchondral bone microfracture, autologous chondrocyte or mesenchymal stem cells (MSC) implantation and osteochondral plugs used in a sequential fashion pending severity and duration of the problem (Figure 1) (Williams et al, 2010;Steinert et al, 2007). Current strategies in human medicine for treatment of diffuse joint degeneration rely on replacement of the whole degenerated joint with inert implants.…”

“…ACI = autologous chondrocyte implantation, MACI = matrix-assisted autologous chondrocyte implantation, TJR = total joint replacement. Reprinted with permission from Williams et al (2010) …”

“…Chondrocytes unfortunately tend to dedifferentiation towards the fibroblast cell lineage when expanded in culture making them less suitable for transplantation (Schulze-Tanzil, 2009). Another limitation to the use of autologous chondrocytes is the need for two surgical procedures, weeks apart to harvest and later implant the cells, which adds time, cost, anesthetic risk and risks of donor site morbidity (Schulze-Tanzil, 2009;Williams et al, 2010). Interestingly, osteoarthritic chondrocytes seem to perform equally well in vitro when compared to chondrocytes from healthy joints (Dehne et al, 2009;Stoop et al, 2007).…”

Polar Histograms of Curvature for Quantifying Skeletal Joint Shape and Congruence

“…Studies in evolutionary biology have continually sought to discern the morphological differences that have led to functional differences among taxa [1,2]. Similarly, differences in articular shape and congruence within species may grant insight into pathological processes such as OA [3][4][5][6][7]-a progressive disease of articular cartilage and bone [8][9][10][11] whose underlying pathoetiology is believed to be mediated by altered joint mechanics [12][13][14].…”

The Proteoglycan Metabolism of Articular Cartilage in Joint-Scale Culture

“…1,2 The shortage of available donor tissue 3 has stimulated tissue engineering efforts to generate large, appropriately shaped, joint-scale osteochondral fragments. [4][5][6][7][8] Allografts are currently stored at the joint scale, and the properties of cartilage in such stored allografts provide the standard for large tissue-engineered constructs.…”