Proffen B, von Keudell A, Vavken P
Department of Orthopedic Surgery, Children's Hospital Boston, Massachusetts, United States.
Z Orthop Unfall. 2012 Jun;150(3):280-9. doi: 10.1055/s-0031-1298387. Epub 2012 Jun 21.
The treatment of cartilage defects has seen a shift from replacement to regeneration in the last few years. The rationale behind this development is the improvement in the quality-of-care for the growing segment of young patients who are prone to arthroplasty complications because of their specific characteristics - young age, high level of activity, high demand for functionality. These days, two of the most popular regenerative treatments are microfracture and autologous chondrocyte implantation (ACI). Although these new options show promising results, no final algorithm for the treatment of cartilage lesions has been established as yet.
The objective of this review is to describe and compare these two treatment options and to present an evidence-based treatment algorithm for focal cartilage defects.
Microfracture is a cost-effective, arthroscopic one-stage procedure, in which by drilling of the subchondral plate, mesenchymal stem cells from the bone marrow migrate into the defect and rebuild the cartilage. ACI is a two-stage procedure in which first chondrocytes are harvested, expanded in cell culture and in a second open procedure reimplanted into the cartilage defect. Microfracture is usually used for focal cartilage defects < 4 cm2, the treated defect size of the ACI seems to have a wider range. The effectiveness of these two treatments has been shown in long-term longitudinal studies, where microfracture showed improvement in up to 95 % of patients, whereas 92 % of the patients in a 2-9 year period of follow-up after ACI showed improvements, respectively. The successful outcome of the treatment depends on multiple factors such as the location of the defect, cell differentiation and proliferation, concomitant problems, and the age of the patient. Associated complications and disadvantages of the two different applications are, for the microfracture patient, a poor tissue differentation or a formation of an intra-lesional osteophyte, and for the ACI patient, periosteal hypertrophy and the need for two procedures in ACI. Only a few studies provide detailed and evidence-based information on a comparative assessment. These studies, however, are showing widely similar clinical outcomes but better histological results for ACI, which are likely to translate into better long-term outcomes.
Although evidence-based studies comparing microfracture and ACI have not found significant differences in the clinical outcome, the literature does show that choosing the treatment based on the size and characteristics of the osteochondral lesion might be beneficial. The American Association of Orthopedic Surgeons suggest that contained lesions < 4 cm2 should be treated by microfracture, lesions bigger than that by ACI.
在过去几年中，软骨缺损的治疗已从置换转向再生。这种发展背后的基本原理是，对于越来越多因特定特征（年轻、活动水平高、功能需求高）而容易出现关节置换并发症的年轻患者，医疗质量得到了改善。如今，两种最流行的再生治疗方法是微骨折和自体软骨细胞植入（ACI）。尽管这些新方法显示出了有前景的结果，但尚未建立治疗软骨损伤的最终算法。
本综述的目的是描述和比较这两种治疗方法，并提出一种基于证据的局灶性软骨缺损治疗算法。
微骨折是一种经济有效的关节镜一期手术，通过钻透软骨下骨板，骨髓间充质干细胞迁移到缺损处并重建软骨。ACI是一种两期手术，首先采集软骨细胞，在细胞培养中扩增，然后在第二次开放手术中重新植入软骨缺损处。微骨折通常用于面积小于4平方厘米的局灶性软骨缺损，ACI治疗的缺损大小范围似乎更广。这两种治疗方法的有效性已在长期纵向研究中得到证实，其中微骨折显示高达95%的患者病情有所改善，而ACI术后2至9年随访期内分别有92%的患者病情改善。治疗的成功结果取决于多种因素，如缺损的位置、细胞分化和增殖、伴随问题以及患者的年龄。这两种不同应用的相关并发症和缺点，对于微骨折患者来说，是组织分化不良或损伤内骨赘形成，对于ACI患者来说，是骨膜肥大以及ACI需要进行两次手术。只有少数研究提供了关于比较评估的详细且基于证据的信息。然而，这些研究显示出临床结果广泛相似，但ACI的组织学结果更好，这可能会转化为更好的长期结果。
尽管比较微骨折和ACI的基于证据的研究尚未发现临床结果有显著差异，但文献确实表明，根据骨软骨损伤的大小和特征选择治疗方法可能是有益的。美国骨科医师协会建议，面积小于4平方厘米的局限性损伤应采用微骨折治疗，大于该面积的损伤采用ACI治疗。
