Purpose: Centred degeneration of the shoulder joint is defined as a degeneration of the glenohumeral surfaces without ascension of the humeral head. We investigated the influence of partial or full thickness rotator cuff tears and/or fatty degeneration of the supraspinatus on the results of total shoulder arthroplasty.

Material and methods: During a multicentric review of 766 cases of centred degeneration of the shoulder joint treated with the Aequalis prosthesis, we identified 555 shoulders in 478 patients with an interpretable preoperative arthroscan. All patients were reviewed with a minimum follow-up of two years (mean 3.6 years). Constant score and radiological findings were recorded. We identified 41 shoulders with partial tears of the supraspinatus and 42 shoulders with full-thickness tears of the supraspinatus alone. Moderate fatty degeneration was observed in 90 shoulders (≤ 2) and severe fatty degeneration of the infraspinatus or the subscapularis (> 2) in 15. We analysed the Constant scores, subjective results, radiological results, and rate of complications in each of these populations.

Results: Rotator cuff tears involving the supraspinatus alone did not have a destabilising effect, the head of the humerus did not influence the postoperative result assessed by the overall Constant score, motion in all planes, subjective result, radiological result, or rate of complications. There was no significant difference in complication rate. Presence or not of cuff repair did not influence these results. Inversely, fatty degeneration ≥ 2 involving the infrastpinatus or the subscapularis had a significant effect, decreasing the Constant score, active external rotation, active anterior elevation, and subjective result. On the contrary, it did not influence the radiological results or the rate of complications.

Discusssion: This multicentric study confirms that the degenerated shoulder joint can remain centred with a solitary tear of the supraspinatus. This has no effect on the clinical result and does not require repair. Inversely, fatty degeneration is highly predictive of the quality of the final result.

Purpose: The best strategy to adopt for the long head of the biceps during total shoulder arthroplasty for centred primary joint degeneration remains a controversial issue. We analysed the influence of long head of the biceps (LHB) tenodesis on outcome.

Material and methods: From retrospective multicentric series of 766 shoulder prostheses implanted for centred primary degeneration of the shoulder joint, we selected 625 shoulders with sufficient data concerning the LHB. We defined two groups: 131 shoulders with LHB tenodesis and 494 shoulders with a preserved LHB. We analysed clinical outcome with the Constant score and subjective outcome at two years. We identified four groups: 70 humeral prostheses without tenodesis, 10 humeral prostheses with tenodesis, 424 total shoulder arthroplastues without tenodesis, and 121 total shoulder arthroplasties with tenodesis.

Results: The Constant score was significantly better in the tenodesis group (74.7) than in the group without tenodesis (70.8). This significant difference was also found for the weighted score and likewise for active anterior elevation and active external rotation in position 1. There was no difference concerning postoperative fatty degeneration. By subgroups, the analysis showed significant improvement in the Constant score for humeral prostheses with tenodesis and total shoulder arthroplasty with tenodesis over the same implants without tenodesis. This same significant difference was observed for the 364 patients who had a minimum follow-up of 36 months: tenodesis improved the Constant score, the weighted Constant score, active anterior elevation, and active external rotation.

Discussion: The causal role of the LHB in shoulder pain is now well documented in the literature. Several authors have advocated tenotomy or tenodesis of the LHB during surgical treatment of rotator cuff tears. The same is not true for shoulder arthroplasty for the treatment of primary degeneration. Dines and Hersch reported their experience with ten patients with a painful total shoulder arthroplasty who were improved with arthroscopic tenotomy or tenodesis.

Conclusion: Our large series confirms that tenodesis of the LHB is preferable during implantation of a humeral prosthesis or a total shoulder prosthesis for the treatment of centred primary joint degeneration with good results that persist over time.