Investigation of microstructural alterations of the human subchondral bone following microfracture penetration reveals effect of three-dimensional device morphology

Subchondral Drilling Independent of Drill Hole Number Improves Articular Cartilage Repair and Reduces Subchondral Bone Alterations Compared With Debridement in Adult Sheep

BACKGROUND

Subchondral drilling is an established marrow stimulation technique for small cartilage defects, but whether drilling is required at all and if the drill hole density affects repair remains unclear.

HYPOTHESES

Osteochondral repair is improved when the subchondral bone is perforated by a higher number of drill holes per unit area, and drilling is superior to defect debridement alone.

STUDY DESIGN

Controlled laboratory study.

METHODS

Rectangular full-thickness chondral defects (4 × 8 mm) were created in the trochlea of adult sheep (N = 16), debrided down to the subchondral bone plate without further treatment as controls (no treatment; n = 7) or treated with either 2 or 6 (n = 7 each) subchondral drill holes (diameter, 1.0 mm; depth, 10.0 mm). Osteochondral repair was assessed at 6 months postoperatively by standardized (semi-)quantitative macroscopic, histological, immunohistochemical, biochemical, and micro-computed tomography analyses.

RESULTS

Compared with defect debridement alone, histological overall cartilaginous repair tissue quality (P = .025) and the macroscopic aspect of the adjacent cartilage (P≤ .032) were improved after both drilling densities. Only drilling with 6 holes increased type 2 collagen content in the repair tissue compared with controls (P = .038). After debridement, bone mineral density was significantly decreased in the subchondral bone plate (P≤ .015) and the subarticular spongiosa (P≤ .041) compared with both drilling groups. Debridement also significantly increased intralesional osteophyte sectional area compared with drilling (P≤ .034). No other differences in osteochondral repair existed between subchondral drilling with 6 or 2 drill holes.

CONCLUSION

Subchondral drilling independent of drill hole density significantly improves structural cartilage repair compared with sole defect debridement of full-thickness cartilage defects in sheep after 6 months. Subchondral drilling also leads to a better reconstitution of the subchondral bone compartment below the defects. Simultaneously, drilling reduced the formation of intralesional osteophytes caused by osseous overgrowth compared with debridement.

CLINICAL RELEVANCE

These results have important clinical implications, as they support subchondral drilling independent of drill hole number but discourage debridement alone for the treatment of small cartilage defects. Clinical studies are warranted to further quantify the effects of subchondral drilling in similar settings.

Surgical therapy in osteoarthritis

OBJECTIVE

To provide an evidence-based overview of the different surgical procedures in osteoarthritis (OA).

DESIGN

This narrative review reports on surgical therapies (1) for severe, end stage OA and (2) of surgical options aiming to possibly reduce OA development earlier in the course of the disease.

RESULTS

Surgical practice guidelines provide evidence-based recommendations to assist in the clinical decision-making. Total joint arthroplasty represents the only valuable, established surgical option for severe, end stage OA. For hip and knee OA, it is by far the most common surgical procedure and provides considerable pain relief, functional restoration, and improved quality of life. Surgical therapy aiming to postpone OA essentially addresses extra- or intraarticular pre-osteoarthritic deformities, defined as congenital or acquired disturbances of the joint structure that adversely affect its function. Approaches in this category include osteotomies and different cartilage repair procedures such as osteochondral autograft and allograft transfer, marrow stimulation techniques, and autologous chondrocyte implantation. However, they are not only less commonly performed than arthroplasty, but the scientific clinical evidence in favour of this type of surgery to reduce the long-term risk of developing OA is considerably reduced.

CONCLUSION

Total knee and hip arthroplasty are two of the most successful procedures in all of medicine. As the progression of this insidious disease is often asymptomatic and slow, it is imperative to judge reparative procedures at their potential to reduce OA development at long-term, besides their primary clinical outcomes. Evidence-based guidelines provide a valuable tool for high-quality surgical decision making in OA.

Ectopic models recapitulating morphological and functional features of articular cartilage

BACKGROUND

Articular cartilage is an extremely specialized connective tissue which covers all diarthrodial joints. Implantation of chondrogenic cells without or with additional biomaterial scaffolds in ectopic locationsin vivo generates substitutes of cartilage with structural and functional characteristics that are used in fundamental investigations while also serving as a basis for translational studies.

METHODS

Literature search in Pubmed.

RESULTS AND DISCUSSION

This narrative review summarizes the most relevant ectopic models, among which subcutaneous, intramuscular, and kidney capsule transplantation and elaborates on implanted cells and biomaterial scaffolds and on their use to recapitulate morphological and functional features of articular cartilage. Although the absence of a physiological joint environment and biomechanical stimuli is the major limiting factor, ectopic models are an established component for articular cartilage research aiming to generate a bridge between in vitro data and the clinically more relevant translational orthotopic in vivo models when their limitations are considered.