Hombro/Shoulder/Schulter/Épaule: Convertir sin producir más tensión

Conversion of hemi into reverse shoulder arthroplasty: implant design limitations.
Teschner H, Vaske B, Albrecht UV, Meller R, Liodakis E, Wiebking U, Krettek C, Jagodzinski M.
Arch Orthop Trauma Surg. 2014 Nov 4. [Epub ahead of print]

Abstract

PURPOSE:
Cranial migration of shoulder hemiarthroplasties due to rotator cuff insufficiency typically requires conversion into a reverse total shoulder arthroplasty. This study was conducted to analyze differences between the height and offset of six implants designed to enable conversion of a hemiarthroplasty into a reverse system.

METHODS:
Anteroposterior radiographs of 40 shoulders were taken. An image analyzing software was used to simulate the implantation of the hemiprostheses. Then the implant was dissembled, leaving on the stem within the humeral shaft. Finally, the implantation of a reverse system was simulated using the stem in the same position. Values are reported as ∆-height and ∆-offset ± standard deviation. Significance was assumed for P < 0.05.

RESULTS:
The least decrease in height was determined for Implantcast with 11.6 ± 3.3 mm, followed by DePuy (16 ± 5.7 mm) and the greatest for Tornier with 33 ± 5.3 mm. No significant differences were found among Exactech, Mathys and Zimmer. The largest offset-deviation was calculated for DePuy (-21.7 ± 3.7 mm) and the smallest for Implantcast (-3.3 ± 2.8 mm) and Tornier (1.5 ± 5.7 mm).

CONCLUSIONS:
Due to the modular stem, the system of Implantcast can be converted in a reverse system with the least changes in height and offset. For the other manufacturers it does not seem possible to convert a hemiprosthesis to a reversed prosthesis without accepting additional tension of the deltoid muscle. Further experimental studies have to analyze the changes in deltoid abduction moments after conversion of a hemi- into a reversed prosthesis.

Hombro/Shoulder/Schulter/Épaule: las fracturas de húmero proximal en mayores con el manguito roto

Prevalence of rotator cuff tears in operative proximal humerus fractures
Andrew Choo, Garret Sobol, Mitchell Maltenfort, Charles Getz, Joseph Abboud
Orthopedics 2014 November 1, 37 (11)

Proximal humerus fractures and rotator cuff tears have been shown to have increasing rates with advancing age, theoretically leading to significant overlap in the 2 pathologies. The goal of this study was to examine the prevalence, associated factors, and effect on treatment of rotator cuff tears in surgically treated proximal humerus fractures.

A retrospective review was performed of all patients who had surgery for a proximal humerus fracture from January 2007 to June 2012 in the shoulder department of a large academic institution. Patient demographics, the presence and management of rotator cuff tears, and surgical factors were recorded. Regression analysis was performed to determine which factors were associated with rotator cuff tears.

This study reviewed 349 fractures in 345 patients. Of these, 30 (8.6%) had concomitant rotator cuff tears. Those with a rotator cuff tear were older (average age, 68.7 vs 63.1 years), were more likely to have had a dislocation (40% vs 12.5%), and were more likely to have undergone subsequent arthroscopic repair or reverse total shoulder arthroplasty than those without a rotator cuff tear. Most (22 of 30) were treated with suture repair at the time of surgery, but 5 patients underwent reverse total shoulder arthroplasty based primarily on the intraoperative finding of a significant rotator cuff tear.

A concomitant rotator cuff tear in association with a proximal humerus fracture is relatively common. Rotator cuff tears are associated with older patients and those with a fracture-dislocation. In rare cases, these cases may require the availability of a reverse shoulder prosthesis.

Hombro/Shoulder/Schulter: prótesis de hombro invertida para mayores con fracturas complejas de humero proximal

Treatment of proximal humeral fractures with reverse shoulder arthroplasty in elderly patients.

Iacobellis C, Berizzi A, Biz C, Camporese 

Musculoskelet Surg 2014 Jun 11

BACKGROUND

Proximal humeral fractures in four or even only three parts, with metaphyseal hinge distances of <8 mm, represent a serious and widely debated problem. Reduction is complex and plating is often instable, especially in elderly patients. Failures, sometimes involving necrosis of the head, are frequent. Hemiarthroplasty has long been used for 3- or 4-part complex fractures, even in young patients, although often with sub-optimal results, due to reabsorption of tuberosities. This complication has partly been overcome with reverse shoulder prostheses which, although more invasive than partial ones, may lead to less disappointing results, even in cases of reabsorption of tuberosities. We have data on a homogeneous series of patients treated with reverse shoulder arthroplasty for proximal fractures, with a maximum follow-up of 10 years. The aim of this study was mainly to identify which cases can be selected for effective treatment and which technical aspects are best to adopt.

MATERIALS AND METHODS

There were 33 patients in this study, mean age 76.6 years (range 54-85). Fractures were classified according to Neer. Surgery was undertaken on average 4.4 days after trauma. The deltopectoral approach was used. Sutures were hooked over the major and lesser tubercles for later reduction and fixation after the prosthesis had been applied. This passage was sometimes not possible in cases of serious degeneration of the rotator cuff. One day after surgery, a shoulder brace providing an abducted angle of 15° was applied for 30 days. Patients were re-assessed with DASH and Constant scores (CS), and the ratio between healthy and operated shoulders was calculated. Physical examination was followed by X-rays, mainly to evaluate and classify any infraglenoid scapular notching according to Nerot.

RESULTS

Mean follow-up was 42.3 months (range 10-121). According to the CS, mean pain was 12.6/15 (range 3-15/15), activities of daily living 16.3/20 (range 8-20/20), ROM 21.8 (range 8-32/40) and power 5.4/25 (range 2-12/25). Total mean CS was 56.4 (range 23-80/100). The mean DASH score was 49.7 (range 32-90). The ratio of the CS parameters between opposite and operated shoulders was on average 72.8 % (range 28-90 %). Long-term complications were eight cases of scapular notching (24.2 %) of which four of grade 2 (12.1 %) and four of grade 1 (12.1 %).

CONCLUSIONS

Total reverse prostheses are more invasive because they also compromise the glenoid surface of the scapula, but they do offer good stability, even in cases of damage to the rotator cuff. Reverse prostheses have great advantages as regards to ROM, allowing functional recovery, which is good in cases with re-insertion of tuberosities, and acceptable in cases when tuberosities are not re-inserted or resorbed. In our cases, the first 3 reverse prostheses lasted 10, 8.3 and 7.3 years, and we believe that they will become increasingly long-lived, so that applying them in cases of complex fractures becomes more feasible. We prefer the deltopectoral approach because it can reduce and stabilize possible intra-operative diaphyseal fractures. Possible scapular notching must be foreseen when inserting the glenosphere. We had eight cases (24.2 %), of which four were Nerot grade 1 and four were grade 2. Applying the Kirschner wire in an infero-anterior position allows the glenosphere to be lowered with a tilt of 10°. Reverse prostheses are suitable for 3- or 4-part complex proximal humeral fractures in patients over 65. Prolonged physiokinesitherapy is essential.