Possibilities for arthroscopic treatment of the ageing sternoclavicular joint

Abstract

Aim: To investigate if there are typical degenerative changes in the ageing sternoclavicular joint (SCJ), potentially accessible for arthroscopic intervention.

Methods: Both SCJs were obtained from 39 human cadavers (mean age: 79 years, range: 59-96, 13 F/26 M). Each frozen specimen was divided frontally with a band saw, so that both SCJs were opened in the same section through the center of the discs. After thawing of the specimens, the condition of the discs was evaluated by probing and visual inspection. The articular cartilages were graded according to Outerbridge, and disc attachments were probed. Cranio-caudal heights of the joint cartilages were measured. Superior motion of the clavicle with inferior movement of the lateral clavicle was measured.

Results: Degenerative changes of the discs were common. Only 22 discs (28%) were fully attached and the discs were thickest superiorly. We found a typical pattern: Detachment of the disc inferiorly in connection with thinning, fraying and fragmentation of the inferior part of the disc, and detachment from the anterior and/or posterior capsule. Severe joint cartilage degeneration ≥ grade 3 was more common on the clavicular side (73%) than on the sternal side (54%) of the joint. In cadavers < 70 years 75% had ≤ grade 2 changes while this was the case for only 19% aged 90 years or more. There was no difference in cartilage changes when right and left sides were compared, and no difference between sexes. Only one cadaver - a woman aged 60 years - had normal cartilages.

Conclusion: Changes in the disc and cartilages can be treated by resection of disc, cartilage, intraarticular osteophytes or medial clavicle end. Reattachment of a degenerated disc is not possible.

Keywords: Arthroscopy; Cartilage; Degenerative; Disc; Sternoclavicular.

Figure 1

The two standard portals for sternoclavicular arthroscopy.

Figure 2

Sternoclavicular arthroscopy performed with the patient supine, using a 2.7 mm arthroscope and a 4.0 mm shaver.

Figure 3

Arthroscopic view of the left sternoclavicular joint showing degenerative changes in the partially resected disc (in the middle) and chondral degeneration of the clavicular cartilage (right side of photo). The shaver is introduced through the superior portal.

Figure 4

The sternoclavicular joints were divided frontally with a thin band saw so that both sternoclavicular joints were unfolded in the same section through the center of the discs.

Figure 5

Measurement of the height of the articular cartilages (cranial-caudal) on the clavicle (A) and manubrium (B).

Figure 6

Probing the attachments of the intraarticular disc to the clavicle and first rib-manubrium junction as well as to the anterior and posterior capsule with a hooked arthroscopic probe.

Figure 7

Measurement of the thickest and thinnest parts of the intraarticular discs with a calliper gauge.

Figure 8

Graphic visualization of the attachments we found of the discs in left (left) and right (right) sternoclavicular joints of males and females. Black lines: Full attachment of all four sectors; red lines: Attachment of three sectors; green lines: Attachment of two sectors; blue lines: Attachment of one sector only. inf: Inferior, sup: Superior; post: Posterior; ant: Anterior.

Figure 9

With inferior detachment (the sternoclavicular joint to the left) there was a substantial increase in supero-medial displacement of the medial clavicular end when a light medially directed push was applied to the lateral clavicle shaft (A: Light pull, B: Push). With full attachment of the disc (as seen in the joint to the right) this displacement was much smaller. Blue dots were marked when no external forces were applied to the joints.