Purpose: The glenoid and humeral head curvature radii are mismatched in non-constrained total shoulder prostheses. The purpose of this study was to evaluate the effect of this mismatch on radiographic lucent lines and clinical outcome.

Material and methods: The study population included 319 total shoulder prostheses issuing from a multicentric European cohort. The patients underwent surgery for primary shoulder degeneration. Mean age at surgery was 67 years. Female sex predominated (75%). Partial supraspinatous tears were present in 7% of the shoulders with full-thickness tears also in 7%. A single type of prosthesis was used composed of a humeral pivot with a modular head (seven head sizes) and a cemented polyethylene flat-surface spiked glenoid (three sizes). Variable association of humeral heads and prosthetic glenoids defined the mismatch which varied from 0 to 10 mm (difference in the curvature radii between the head and glenoid). The patients were reviewed clinically and radiologically at a mean follow-up of 53.5 months (24–110 months). Clinical outcome was assessed with the Constant score for pain (15 points), daily activity (20 points), motion (40 points), and force (25 points). The glenoid lucent line was evaluated on the AP view using a 0 to 18 point scale (0=absence, 18=lucent line in 6 zones). Analysis of variance and linear regression were used to assess the effect of mismatch on the glenoid lucent line and clinical outcome.

Results: There was a statistically significant linear relationship between mismatch and glenoid lucent lines. The lucent line score was significantly lower when the mismatch was between 6 and 10mm. Mismatch had no influence on the overall Constant score or the individual scores (pain, motion, force, daily activities) nor on early or late postoperative complications.

Discussion: Based on the results of this study, the first in vivo assessment, the “ideal” gleno-humeral mismatch for total shoulder prostheses would be between 6 and 10 mm, i.e. much greater than is classically recommended (0–5 mm).

Purpose: Nonunion of the surgical neck of the humerus can occur after orthopaedic or poorly-adapted surgery after displaced subtuberosity or cephalotuberosity fracture. The purpose of this study was to report functional and radiographic outcome after treatment with shoulder prosthesis.

Material and methods: Twenty-two patients who had a non-constrained shoulder prosthesis were included in this retrospective multicentric study. Mean age was 70 years and mean follow-up was 45 months (range 2 – 9 years). The initial fracture had two fragments in six patients and was a three-fragment fracture involving the head and the tubercle in thirteen and a four-fragment fracture in three. Orthopaedic treatment was given in ten cases and surgical osteosynthesis was used in twelve. Time from fracture to implant insertion was 20 months. The deltopectoral approach was used for 21 humeral implants and one total shoulder arthroplasty (glenohumeral degeneration). The tuberosities were fixed to the cemented humeral stem and a crown of bone grafts were placed around the nonunion of the surgical neck. All patients were reviewed after a minimum of two years and assessed with the Constant score and x-rays.

Results: The absolute Constant score improved from 23 reoperatively to 39 postoperatively with an anterior elevation of 53° to 63°. Pain score (from 3 to 9, p = 0.001) and external rotation (from 13° to 28°, p = 0.01) were significantly improved. Forty-five percent of the patients were satisfied and 55% were dissatisfied. The type of initial treatment, type of initial fracture, and time before implantation of the prosthesis did no affect final outcome. The complication rate was 36% (eight patients), and led to five revision procedures. The radiographic work-up disclosed six cases of persistent nonunion of the greater tuberosity, two proximal migrations of the prosthesis, and one humeral loosening.

Conclusion: Outcome of shoulder prosthesis for sequela after fracture of the proximal humerus with nonunion of the surgical neck is poor. No improvement in anterior elevation, force, or motion was achieved. Shoulder prosthesis for sequelae of fracture of the proximal humerus with nonunion of the surgical neck should be considered as a “limited-objective” indication only providing beneficial pain relief.

Purpose: Collapse or necrosis of the head of the humerus after fracture of the proximal humerus can be an indication for shoulder arthroplasty. The poor results classically reported have led to a search for factors predictive of the anatomic and functional outcome after arthroplasty for fracture sequelae.

Material and methods: Among the 221 Aequalis prostheses implanted for the treatment of sequelae after fracture of the proximal humerus, 137 (62%) developed post-traumatic avascular osteonecrosis of the humeral head with a deformed callus of the tuberosity. Head tilt was in a valgus position in 83 shoulders and in a varus position in 54. Mean age was 61.49 years. The initial fractures were subtuberosity fractures in 20% of the cases, three-fragment fractures in 32%, and cephalobituberosity fractures with four fragments in 48% of the cases.Twenty-five percent of the patients had undergone initial osteosynthesis. The rotator cuff was repaired in 4.5%, and two osteotomies of the less tuberosity and four osteotomies of the greater tuberosity were performed at implantation. Pre- and postoperative clinical and functional outcomes were assessed with the Constant score and a function index composed of eleven usual movements.

Results: Mean follow-up was 44 months (24–104), with a mean 42° gain in anterior elevation and a 29° gain in external rotation. The gain in the Constant score was +32 points (mean score 61), and +43% with the weighted score. The four subscores (pain, motion, activity, force) improved two-fold. Analysis of the eleven usual movements demonstrated recovery in 88% of the patients. The subjective satisfaction index was 86%. The mean Constant score improved significantly more after total arthroplasty (67 points) than after humerus prosthesis (55 points). Complications (per- or postoperative mechanical problem, infection, neurological disorder) or the need for revision were unfavourable elements.

Discussion: Deformation and deviation of the tuberosities, especially the greater tuberosity, often leads to osteotomy during the implantation procedure. In this series, osteotomies were exceptional and functional outcomes showed that deviated tuberosities could be preserved without having an unfavourable effect on functional prognosis. Much on the contrary, the absence of a tuberosity osteotomy simplified the operative procedure and produced much better functional outcome than observed in earlier studies. The rate of complication for secondary prosthetic implantation is not negligible (15%) and a simplified procedure without osteotomy is a useful criterion. Furthermore, rehabilitation may be started earlier after implantation when it is not retarded by osteotomy bone healing, found to be an unfavourable factor.

Conclusion: Implantation of a shoulder prosthesis after collapse or necrosis of the head of the humerus after proximal fracture with varus or valgus impaction has provided good functional outcome without tuberosity osteotomy since the deformation of the tuberosity is generally well tolerated.

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.

Purpose: The indication for humeral or total shoulder prosthesis in patients with avascular osteonecrosis of the shoulder depends on the radiographic stage of the necrosis. The purpose of this study was to analyse the prognostic radiographic features enabling proper identification of the indications for humeral or total prostheses.

Material and methods: This retrospective multicentric study included 53 shoulders operated on for prosthetic repair of avascular osteonecrosis. There were 20 men and 29 women, mean age 57 years. A humeral prosthesis was used in 34 cases and a total prosthesis in 19. Clinical assessment was based on the Constant score and the radiographic analysis used the Arlet and Ficat classification. Staging was II (n=4), III (n=16), IV (n=21) and V (n=12). Independently of the radiographic stage of necrosis, three characteristic groups were defined. Group 1 (19 shoulders) included necrosis without bony collapse of the humeral head. Group 2 (20 shoulders) included necrosis with bony collapse of the humeral head with preservation of the anatomic relations with the glenoid cavity. Group 3 (14 shoulders) included necrosis with bony collapse and impaction of the humeral head in the glenoid with medialisation of the humerus.

Results: Preoperatively, presence of bony collapse was associated with decreased pain and motion score. Major joint stiffness was noted in group 3 (8). The humeral prosthesis gave similar results for groups 1 and 2 (Constant score 73 and 75.3). Less satisfactory results was the rule in group 3 (Constant score 51.6). There was a postoperative erosion of the glenoid cavity in 83% of the shoulders in group 3 versus 12.5% in group 1 and 17% in group 2. The total prosthesis optimised results despite persistence of a difference between groups 2 and 3 (Constant score 83 and 64 respectively).

Discussion: Destabilisation of the glenohumeral joint by impaction of the humeral head against the glenoid cavity has an effect on the clinical result of the prosthetic surgery. Preservation of the anatomic relations of the articulation (groups 1 and 2) appears to be necessary for good results. Impaction medialisation of the humerus has a negative effect on the clinical result of humeral prostheses with a risk of glenoid erosion.

Conclusion: Independently of radiographic stage of necrosis, the presence of humeral impaction with medi-alisation should be considered individually as it has a negative effect on the clinical outcome of these prostheses, particularly humeral prostheses.