The Conformity of Rehabilitation Protocols Used for Different Cartilage Repairs of the Knee Joint—A Review on Rehabilitation Standards in German Speaking Countries

The present study analysed current rehabilitation protocols to investigate whether there is a standard for early rehabilitation after microfracturing (MFX), matrix-assisted cartilage transplantation (MACT), and osteochondral autograft transfer (OATS) of the knee joint in clinical routine, and if rehabilitation protocols differ in the repair technique used or the localization of the cartilage defect. The evaluation included rehabilitation criteria such as weight-bearing, range of motion, use of an orthosis, motion therapy, and rehabilitation training during the early rehabilitation phase after MFX, MACT, and OATS of the femorotibial and retropatellar joint space. We analysed 153 rehabilitation protocols after cartilage repair of the knee joint, including 137 protocols for after repair of the main weight-bearing (femorotibial) area and 16 for after retropatellar cartilage repair. Most of the protocols differed significantly according to the location of the repair and the procedure performed. Our findings indicate that full weight-bearing can be achieved significantly faster after MFX (5.6 weeks) and OATS (5.3 weeks) than after MACT of the main weight-bearing zone (6.6 weeks, p < 0.001). In addition, after retropatellar cartilage repair, patients are allowed full weight-bearing after 2.1 weeks compared to the main weight-bearing zone (5.3–6.6 weeks; p < 0.001). No standardized rehabilitation recommendations have been established. The present study shows that rehabilitation needs to be adjusted to the surgical technique and the location of the defect zone, and further investigation is warranted to establish standardized rehabilitation protocols after cartilage repair of the knee joint.

Small Cartilage Defect Management

Cartilage defects in the knee are common resulting in significant pain and morbidity over time. These defects can arise in isolation or concurrently with other associated injuries to the knee. The treatment of small (< 2–3 cm2) cartilage deficiencies has changed as our basic science knowledge of tissue healing has improved. Advancements have led to the development of new and more effective treatment modalities. It is important to address any associated knee injuries and limb malalignment. Surgical options are considered when nonoperative treatment fails. The specific procedure depends on individual patient characteristics, lesion size, and location. Debridement/chondroplasty, microfracture, marrow stimulation plus techniques, fixation of unstable osteochondral fragments, osteochondral autograft transfer, and osteochondral allograft transplantation, all have roles in the treatment of small cartilage defects.

Trends in the Surgical Treatment of Articular Cartilage Lesions in the United States from 2007 to 2016

Management of cartilage lesions of the knee can be complex, time consuming, and controversial, especially without a widely agreed upon “gold-standard” management. The PearlDiver database (www.pearldiverinc.com, Fort Wayne, IN) was queried for surgical management of cartilage lesions specified by Current Procedure Terminology (CPT) codes: 29877, chondroplasty; 29879, microfracture/drilling; 29866, arthroscopic osteochondral autograft; 29867, arthroscopic osteochondral allograft; 27412, autologous chondrocyte implantation (ACI); 27415, open osteochondral allograft; or 27416, open osteochondral autograft. Procedures were categorized as palliative (chondroplasty), microfracture/drilling, or restorative (arthroscopic osteochondral autograft; arthroscopic osteochondral allograft; ACI; open osteochondral allograft; or open osteochondral autograft). Linear regression was performed to determine the significance of yearly trend across each procedure.From 2007 to 2016, a total of 35,506 surgical procedures were performed. The average yearly incidence was 7.8 per 10,000 patients. Overall, palliative techniques (chondroplasty) were more common (1.8:1 ratio for chondroplasty to microfracture and 34:1 ratio chondroplasty to restoration procedure). There was a trend of decreasing incidence of palliative procedures seen by a significant decrease in the ratio of palliative to microfracture/restorative procedures of 0.2512 each year from 2007 to 2016 (p < 0.001). This decrease followed a linear trend (R 2 = 0.9123). In 2013, the number and incidence of the palliative procedures declined below that of microfracture procedures, with microfracture being most common from 2013 to 2016. Palliative chondroplasty was no longer the most commonly performed procedure for cartilage lesions in the United States from 2007 to 2016, as more surgeons opted for microfracture procedures instead. Restorative procedures (ACI, osteochondral autograft transfer system) remained unchanged over the study period, in accordance with the sports medicine literature; however, early functional outcomes studies do show the equivalency and in some cases superiority compared with microfracture. This is Level III study.

Current solutions for the treatment of chronic articular cartilage defects in the knee

Chondral and osteochondral defects in the knee are common and may lead to degenerative joint disease if treated inappropriately. Conventional treatments such as microfracture often result in fibrocartilage formation and are associated with inferior results. Additionally, microfracture is generally unsuitable for the treatment of defects larger than 2–4 cm2. The osteochondral autograft transfer system (OATS) has been shown to produce superior clinical outcomes to microfracture but is technically difficult and may be associated with donor-site morbidity. Osteochondral allograft use is limited by graft availability and failure of cartilage incorporation is an issue. Autologous chondrocyte implantation (ACI) has been shown to result in repair with hyaline-like cartilage but involves a two-stage procedure and is relatively expensive. Rehabilitation after ACI takes 12 months, which is inconvenient and not feasible for athletic patients. Newer methods to regenerate cartilage include autologous stem cell transplantation, which may be performed as a single-stage procedure, can have a shorter rehabilitation period and is less expensive than ACI. Longer-term studies of these methods are needed. Cite this article: EFORT Open Rev 2020;5:156-163. DOI: 10.1302/2058-5241.5.190031