Grad
0
Normal cartilage
1a
Intact surface, fibrillation, and/or cartilage softening
1b
Additional superficial lacerations/fissures
2
<50% of cartilage thickness affected
3a
>50% of cartilage thickness affected, not involving the calcified layer
3b
>50% of cartilage thickness affected, extend to calcified layer
3c
>50% of cartilage thickness affected, extend to subchondral bone
3d
>50% of cartilage thickness affected, with blistering
4a/b
Complete cartilage defect, extend into subchondral bone
![A428222_1_En_26_Fig1_HTML.jpg](https://i0.wp.com/musculoskeletalkey.com/wp-content/uploads/2017/12/A428222_1_En_26_Fig1_HTML.jpg?w=960)
Fig. 26.1
MRI with intra-articular gadolinium application for better visualization of a chondral lesion at the humerus (ICRS type 4)
26.3 Therapy
To date there is only limited evidence regarding diagnosis and therapy of cartilage defects in the shoulder. Because of this lack of high-level studies, it is still a challenge for the clinicians not only to detect focal cartilage defects but above all to draw the correct conclusions from this diagnosis. As cartilage defects of the shoulder are often additional findings with other pathologies, examination has to make sure that the cartilage defect is in fact a relevant reason for the patient’s symptoms before planning surgery. In cases of detected comorbidities which do not need immediate surgical treatment, it may be advisable to first treat the shoulder conservatively, e.g., by physical therapy. However, it is important that a conservative treatment attempt must not delay surgical cartilage repair unnecessarily, which is why these patients must be reevaluated in a defined period of time to avoid rapid deterioration.
In general cartilage defects grade 3 or 4 according to ICRS classification associated with symptoms of pain or loss of function are indications for surgical cartilage repair. Nowadays there are several operative treatment options for restoration of articular cartilage in the shoulder, like bone marrow stimulating therapies, autologous osteochondral transplantation (OCT), or autologous chondrocyte transplantation (ACT). The choice of therapy is depending on different factors like size and grade of the defect as well as quality of the subchondral bone. However, due to the lack of clinical trials, the indications for cartilage treatment in the shoulder joint are so far not as clearly defined as for other joints, which is why the indications and contraindications are to a big part based on the data for other joints like the knee (Fig. 26.2).
![A428222_1_En_26_Fig2_HTML.gif](https://i0.wp.com/musculoskeletalkey.com/wp-content/uploads/2017/12/A428222_1_En_26_Fig2_HTML.gif?w=960)
![A428222_1_En_26_Fig2_HTML.gif](https://i0.wp.com/musculoskeletalkey.com/wp-content/uploads/2017/12/A428222_1_En_26_Fig2_HTML.gif?w=960)
Fig. 26.2
Flowchart of operative therapy of cartilage defects in the shoulder. MF microfracturing, ACT autologous chondrocyte transplantation, PJR partial joint resurfacing, OCT autologous osteochondral transplantation
26.3.1 Bone Marrow Stimulation
Bone marrow stimulating therapies like microfracturing are indicated in rather smaller cartilage defects (< 2–3 cm2) with good and healthy subchondral bone. The surgical technique is similar to the treatment of other joints like the knee or ankle and can be performed arthroscopically. Initially a careful debridement of the defect using an arthroscopical shaver or curette is necessary, which must be completed down to the subchondral bone including the calcified layer and into healthy surrounding cartilage. Subsequently the subchondral surface is perforated with special awls or drills, so blood containing stem cells can escape from the bone marrow and build a clot in the former defect zone, which over time transforms to fibrocartilage tissue [5]. It is crucial that the often sclerotic subchondral bone is completely perforated, which can be ensured by the leakage of grease drops from the underlying bone marrow. Studies have shown that the optimal distance between the perforations is 3 and 4 mm [13]. Microfracturing of the shoulder is a relatively easy and cost-effective therapy with similar good clinical results in comparison to other joints, if the indication is set properly [4]. Furthermore in comparison to other established cartilage regenerative procedures, an additional surgery at the knee for harvesting autologous osteochondral transplants or chondrocytes is not necessary. However, microfracturing is not indicated for bipolar lesions, and it does not seem suitable for larger cartilage defects of more than 3 cm2 and for patients over 40 years of age. Furthermore compared with other locations like the femorotibial joint, microfracturing in the glenohumeral joint can be quite challenging since the surgeon has to avoid an approach, which is too tangential to the defect. While for the humeral head, this problem can be solved by internal or external rotation of the arm; for defects of the glenoid, the arthroscopical portal should be placed more lateral in order to reach the lesion more vertical (Fig. 26.3).
![A428222_1_En_26_Fig3_HTML.gif](https://i0.wp.com/musculoskeletalkey.com/wp-content/uploads/2017/12/A428222_1_En_26_Fig3_HTML.gif?w=960)
![A428222_1_En_26_Fig3_HTML.gif](https://i0.wp.com/musculoskeletalkey.com/wp-content/uploads/2017/12/A428222_1_En_26_Fig3_HTML.gif?w=960)
Fig. 26.3
(a–d) Schematic representation of the microfracturing technique: (a) careful debridement of the defect zone into healthy surrounding cartilage using a curette; (b) removal of the calcified layer with a sharp spoon curette; (c) perforation of the subchondral bone with the microfracture awl; (d) defect filled with blood clot
26.3.2 Autologous Chondrocyte Transplantation
By now ACT is a standard therapy for the treatment of large (>2cm2) full-thickness chondral lesions with intact subchondral bone in different joints with good clinical outcome. Still clinical experience for the glenohumeral joint is rare, but its application in other joints has shown that ACT is contraindicated in bipolar defects and that previous microfracturing is associated with minor results [9]. In a first operation, chondrocytes are harvested from the posterior-superior zone of the humeral head arthroscopically. Afterward the cells are in vitro cultivated for 4–8 weeks (dependent on the producing company) and then implanted into the defect zone. Also for ACT a careful debridement is necessary prior to implantation; however, in contrast to microfracturing, damage to the subchondral layer and subsequent bleeding from the bone marrow must be avoided as the implanted chondrocytes should not be mixed with stem cells. Especially for defects of the humeral head, matrix-associated ACT (MACT) procedures, where the expanded chondrocytes are imbedded in a three-dimensional collagen bio-scaffold that is fixed in the surrounding cartilage by sutures, have seemed to be advantageous in the past years, as the implanted chondrocytes are distributed more homogeneous in the defect zone on the spherical surface of the humeral head [4]. Though this procedure requires an open approach including the detachment of the subscapularis tendon and therefore it causes a more stringent rehabilitation [2]. Following the recent invention of injectable ACT, where the cultivated cells are contained in albumin hyaluronic acid gels, less invasive arthroscopical or arthroscopical-assisted procedures are possible today; however, the arthroscopical technique still requires a high level of experience by the surgeon.
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