Focal femoral inlay resurfacing has been developed for the treatment of full-thickness chondral defects of the knee. This technique involves implanting a defect-sized metallic or ceramic cap that is anchored to the subchondral bone through a screw or pin. The use of these experimental caps has been advocated in middle-aged patients who have failed non-operative methods or biological repair techniques and are deemed unsuitable for conventional arthroplasty because of their age. This paper outlines the implant design, surgical technique and biomechanical principles underlying their use. Outcomes following implantation in both animal and human studies are also reviewed.

Cite this article: Bone Joint J 2013;95-B:301–4.

Abstract. Introduction. Active, middle-aged patients with symptomatic cartilage or osteochondral defects can find themselves in a treatment gap when they have failed conservative measures but are not yet eligible for conventional arthroplasty. Data from various cohort studies suggests that focal knee resurfacing implants such as HemiCAP, UniCAP, Episealer or BioBoly are cost-effective solutions to alleviate pain, improve function and delay or eliminate the need for conventional replacement. A systematic review and meta-analysis were conducted in order to(i) evaluate revision rates and implant survival of focal resurfacing; (ii) explore surgical complications; and (iii) evaluate various patient reported clinical outcome measures. Methodology. PubMED, Cochrane Library and Medline databases were searched in February 2022 for prospective and retrospective cohort studies evaluating any of the available implant types. Data on incidence of revision, complications and various patient reported outcome measures was sourced. Results. A total of 24 unique studies were identified with a total of 1465 enrolled patients. A revision rate of 12.97% over a 5.9 year weighted mean follow-up period was observed across all implant types. However, in one series a Kaplan-Meir survival as high as 92.6% at a 10-year follow-up period was noted. A statistically significant improvement was documented across multiple subjective clinical outcomes scores. There was a low reported incidence of post-operative complications such as aseptic loosening or deep wound infection. Conclusions. Focal femoral resurfacing appears to be a viable treatment option for focal symptomatic chondral lesions in patients beyond biological reconstruction, with low revision rates and high patient satisfaction

Osteochondritis Dissecans (OCD) is a condition for which the aetiology remains unknown. It affects subchondral bone and secondarily its overlying cartilage and is mostly found in the knee. It can occur in adults, but is generally identified when growth remains, when it is referred to as juvenile OCD. As the condition progresses, the affected subchondral bone separates from adjacent healthy bone, and can lead to demarcation and separation of its associated articular cartilage. Any symptoms which arise relate to the stage of the disease. Early disease without separation of the lesion results in pain. Separation of the lesion leads to mechanical symptoms and swelling and, in advanced cases, the formation of loose bodies.

Early identification of OCD is essential as untreated OCD can lead to the premature degeneration of the joint, whereas appropriate treatment can halt the disease process and lead to healing. Establishing the stability of the lesion is a key part of providing the correct treatment. Stable lesions, particularly in juvenile patients, have greater propensity to heal with non-surgical treatment, whereas unstable or displaced lesions usually require surgical management.

This article discusses the aetiology, clinical presentation and prognosis of OCD in the knee. It presents an algorithm for treatment, which aims to promote healing of native hyaline cartilage and to ensure joint congruity.

Take home message: Although there is no clear consensus as to the best treatment of OCD, every attempt should be made to retain the osteochondral fragment when possible as, with a careful surgical technique, there is potential for healing even in chronic lesions

Cite this article: Bone Joint J 2016;98-B:723–9.