Arthroscopic iliac crest bone grafting in recurrent anterior shoulder instability: minimum 5-year clinical and radiologic follow-up

Purpose: To investigate the clinical and radiologic mid- to long-term results of arthroscopic iliac crest bone-grafting for anatomic glenoid reconstruction in patients with recurrent anterior shoulder instability. Methods: Seventeen patients were evaluated after a minimum follow-up of 5 years. Clinical [range of motion, subscapularis tests, apprehension sign, Subjective Shoulder Value (SSV), Constant Score (CS), Rowe Score (RS), Walch Duplay Score (WD), Western Ontario Shoulder Instability Index (WOSI)], and radiologic [X-ray (true a.p., Bernageau and axillary views) and computed tomography (CT)] outcome parameters were assessed. Results: Fourteen patients [mean age 31.1 (range 18–50) years] were available after a follow-up period of 78.7 (range 60–110) months. The SSV averaged 87 (range 65–100) %, CS 94 (range 83–100) points, RS 89 (range 30–100) points, WD 87 (range 25–100) points, and WOSI 70 (range 47–87) %. The apprehension sign was positive in two patients (14%). One patient required an arthroscopic capsular plication due to a persisting feeling of instability, while the second patient experienced recurrent dislocations after a trauma, but refused revision surgery. CT imaging showed a signifcant increase of the glenoid index from preoperative 0.8±0.04 (range 0.7–0.8) to 1.0±0.11 (range 0.8–1.2) at the fnal follow-up (p<0.01). Conclusion: Arthroscopic reconstruction of anteroinferior glenoid defects using an autologous iliac crest bone-grafting tech nique yields satisfying clinical and radiologic results after a mid- to long-term follow-up period. Postoperative re-dislocation was experienced in one (7.1%) of the patients due to a trauma and an anatomic reconstruction of the pear-shaped glenoid confguration was observed. Level of evidence IV

Subacromial Bursa: A Neglected Tissue Is Gaining More and More Attention in Clinical and Experimental Research

The subacromial bursa has long been demolded as friction-reducing tissue, which is often linked to shoulder pain and, therefore, partially removed during shoulder surgery. Currently, the discovery of the stem cell potential of resident bursa-derived cells shed a new light on the subacromial bursa. In the meanwhile, this neglected tissue is gaining more attention as to how it can augment the regenerative properties of adjacent tissues such as rotator cuff tendons. Specifically, the tight fibrovascular network, a high growth factor content, and the large progenitor potential of bursa-derived cells could complement the deficits that a nearby rotator cuff injury might experience due to the fact of its low endogenous regeneration potential. This review deals with the question of whether bursal inflammation is only a pain generator or could also be an initiator of healing. Furthermore, several experimental models highlight potential therapeutic targets to overcome bursal inflammation and, thus, pain. More evidence is needed to fully elucidate a direct interplay between subacromial bursa and rotator cuff tendons. Increasing attention to tendon repair will help to guide future research and answer open questions such that novel treatment strategies could harvest the subacromial bursa's potential to support healing of nearby rotator cuff injuries

Subacromial Bursa: A Neglected Tissue Is Gaining More and More Attention in Clinical and Experimental Research

The subacromial bursa has long been demolded as friction-reducing tissue, which is often linked to shoulder pain and, therefore, partially removed during shoulder surgery. Currently, the discovery of the stem cell potential of resident bursa-derived cells shed a new light on the subacromial bursa. In the meanwhile, this neglected tissue is gaining more attention as to how it can augment the regenerative properties of adjacent tissues such as rotator cuff tendons. Specifically, the tight fibrovascular network, a high growth factor content, and the large progenitor potential of bursa-derived cells could complement the deficits that a nearby rotator cuff injury might experience due to the fact of its low endogenous regeneration potential. This review deals with the question of whether bursal inflammation is only a pain generator or could also be an initiator of healing. Furthermore, several experimental models highlight potential therapeutic targets to overcome bursal inflammation and, thus, pain. More evidence is needed to fully elucidate a direct interplay between subacromial bursa and rotator cuff tendons. Increasing attention to tendon repair will help to guide future research and answer open questions such that novel treatment strategies could harvest the subacromial bursa’s potential to support healing of nearby rotator cuff injuries

Do Matrix Metalloproteases and Tissue Inhibitors of Metalloproteases in Tenocytes of the Rotator Cuff Differ with Varying Donor Characteristics?

An imbalance between matrix metalloproteases (MMPs) and the tissue inhibitors of metalloproteases (TIMPs) may have a negative impact on the healing of rotator cuff tears. The aim of the project was to assess a possible relationship between clinical and radiographic characteristics of patients such as the age, sex, as well as the degenerative status of the tendon and the MMPs and TIMPs in their tenocyte-like cells (TLCs). TLCs were isolated from ruptured supraspinatus tendons and quantitative Real-Time PCR and ELISA was performed to analyze the expression and secretion of MMPs and TIMPs. In the present study, MMPs, mostly gelatinases and collagenases such as MMP-2, -9 and -13 showed an increased expression and protein secretion in TLCs of donors with higher age or degenerative status of the tendon. Furthermore, the expression and secretion of TIMP-1, -2 and -3 was enhanced with age, muscle fatty infiltration and tear size. The interaction between MMPs and TIMPs is a complex process, since TIMPs are not only inhibitors, but also activators of MMPs. This study shows that MMPs and TIMPs might play an important role in degenerative tendon pathologies

Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

We present phonon dispersions, element-resolved vibrational density of states (VDOS) and corresponding thermodynamic properties obtained by a combination of density functional theory (DFT) and nuclear resonant inelastic X-ray scattering (NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and thin epitaxial films. We see distinct differences in the VDOS of the antiferromagnetic (AF) and ferromagnetic (FM) phase which provide a microscopic proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular sensitivity to the slight tetragonal distortions present in epitaxial films, which is not encountered in the AF phase. This results in a notable change in lattice entropy, which is important for the comparison between thin film and bulk results. Our calculations confirm the recently reported lattice instability in the AF phase. The imaginary frequencies at the $X$-point depend critically on the Fe magnetic moment and atomic volume. Analyzing these non vibrational modes leads to the discovery of a stable monoclinic ground state structure which is robustly predicted from DFT but not verified in our thin film experiments. Specific heat, entropy and free energy calculated within the quasiharmonic approximation suggest that the new phase is possibly suppressed because of its relatively smaller lattice entropy. In the bulk phase, lattice degrees of freedom contribute with the same sign and in similar magnitude to the isostructural AF-FM phase transition as the electronic and magnetic subsystems and therefore needs to be included in thermodynamic modeling.Comment: 15 pages, 12 figure

Sidus Stem-Free Shoulder System for primary osteoarthritis: short-term results of a multicenter study

BACKGROUND: The aim of this prospective multicenter study was to evaluate clinical and radiologic results of a new metaphyseal anchored system. This system features a different anchor geometry that potentially leads to better bony integration and less loosening. METHODS: From November 2012 until December 2015, 148 patients (151 shoulders) were treated with the Sidus Stem-Free Shoulder System at 9 centers in Europe. The main indication was primary osteoarthritis (80.1%). This analysis only includes patients diagnosed with primary osteoarthritis (n = 121). A clinical evaluation was performed using the Constant-Murley score, Subjective Shoulder Value, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, and range of motion. Radiologic assessment was based on the occurrence of radiolucent lines and signs of implant migration, osteolysis, loosening, and heterotopic ossification. RESULTS: We evaluated 105 patients after a follow-up period of 2 years. There were 53 women and 52 men. The average age was 64 years. Total shoulder arthroplasty was performed in 73 cases and hemiarthroplasty in 32. The Constant-Murley score improved from 26 points preoperatively to 70 points at 2 years' follow-up (P < .001). The Subjective Shoulder Value increased from 34% to 84% (P < .001), and the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form increased from 34 points to 86 points (P < .001). Radiologically, neither migration nor loosening was found. However, radiolucent lines of 2 mm or greater could be detected around the glenoid in 2 cases, but none of them have had clinical relevance yet. The overall complication rate was 6.7%, and the revision rate was 0%. CONCLUSION: Patients with the Sidus Stem-Free Shoulder System achieve good clinical and radiologic short-term results that are comparable with the results of other stem-free shoulder implants

New aspects of non-operative and surgical management of anteroinferior shoulder instability

Die konservative Therapie der primärtraumatischen anteroinferioren Schultererstluxation hat mit der Einführung der Außenrotationsimmobilisation einen neuen Aufwind erlebt. Mit einer dreiwöchigen Immobilisation in 10-30° Außenrotation können die Rezidivraten entsprechend aktueller Arbeiten im Vergleich zur herkömmlichen Immobilisation in Innenrotation gesenkt werden. Eine längere Immobilisation für insgesamt fünf Wochen scheint keine wesentlichen Vorteile zu erbringen, was eigene kernspintomographische Daten und erste klinische Ergebnisse zeigen. Einschränkend bleibt zu erwähnen, daß jedoch die optimale Position der Immobilisation noch nicht abschließend geklärt ist. Anteriore Zugangswege zum Schultergelenk im Rahmen von offenen Stabilisierungsverfahren mit einmaliger oder wiederholter Ablösung der Subscapularissehne bergen das Risiko einer iatrogenen Schädigung der muskulotendinösen Einheit. Irreversible Veränderungen des Musculus subscapularis wie die fettige Infiltration mit oder ohne Versagen der Sehnenrekonstruktion können zu einem permanenten partiellen oder totalen Verlust der Muskelfunktion führen. Das Belly-off Zeichen ermöglicht eine exakte Diagnose dieser Problematik. Die klinischen Auswirkungen scheinen vom Ausmaß der Schädigung der muskulotendinösen Einheit abhängig zu sein. Arthroskopische Techniken können die Subscapularismorbidität senken. Anteriore Glenoidranddefekte erfordern entsprechend ihres pathoanatomischen Korrelats und ihrer biomechanischen Relevanz unterschiedliche therapeutische Vorgehensweisen. Mit der offenen Rekonstruktion von anterioren Pfannenranddefekten vom Fragment-Typ (knöchernen Bankart-Läsionen oder Pfannenrandfrakturen) in Fadenankertechnik oder mittels Schraubenosteosynthese können gute klinische Ergebnisse erzielt werden. Auch die Pfannenrandrekonstruktion mit autologer trikortikaler Beckenkammspanplastik bei signifikanten Erosionsdefekten liefert reproduzierbare klinische und radiologische Resultate. Im Hinblick auf die mehrfach diskutierte Subscapularismorbidität und den bekannten Vorteilen der minimal-invasiven Techniken stellen erste arthroskopische Ansätze eine vielversprechende Alternative dar. Mit der virtuellen Glenoidplastik kann ein präzises dreidimensionales Modell kreiert werden, wodurch eine exaktere präoperative Planung und ggf. auch intraoperative Rekonstruktion von Glenoidranddefekten mit signifikantem Substanzverlust erreicht werden kann. Zusammenfassend zeigen sich in der Therapie von anteroinferioren Schulterinstabilitäten neue vielversprechende Ansätze, um die Integrität der statischen Stabilisatoren durch ein konservatives Vorgehen wiederherzustellen. Im Rahmen der operativen Versorgung geht der Trend eindeutig in Richtung minimal-invasiver Rekonstruktionstechniken mit dem Ziel, die Integrität der dynamischen Stabilisatoren aufrecht zu erhalten und die Zugangsmorbidität für die Patienten zu minimieren.Non-operative management of first traumatic anteroinferior shoulder dislocation using the external rotation method has recently received increasing attention. Immobilization of the arm in 10-30° of external rotation for three weeks has been shown to reduce the rate of recurrence compared to the conventional immobilization in internal rotation. Clinical and magnetic resonance imaging studies do not support a prolonged immobilization for a period of five weeks. However, the optimal position of immobilization has yet to be determined. Anterior surgical approaches to the shoulder joint in the context of instability repair using different subscapularis tendon takedown or incision techniques may impair subscapularis recovery. Irreversible changes of the muscle, in particular atrophy and fatty infiltration with or without failure of the tendon repair, may result in permanent loss of subscapularis function. The belly-off sign allows an accurate diagnosis of the problem. The degree and clinical impact of SSC dysfunction seems to vary depending on the damage to the musculotendinous unit. Arthroscopic stabilization procedures seem to prevent the complication of fatty infiltration and preserve the integrity of the subscapularis musculotendinous unit. The treatment of anterior glenoid rim defects depends on its morphology and biomechanical relevance. The open surgical reconstruction of fragment type of lesions using suture anchors or screw osteosynthesis offers reliable clinical results. Erosion type of lesions with significant bone loss can successfully be treated using an autologous iliac crest bone grafting technique. Arthroscopic approaches can reduce the morbidity to the subscapularis muscle and offer general advantages of minimal-invasive procedures. Using the computed tomography based patient-specific modeling of glenoid rim defects a more accurate preoperative planning and intraoperative reconstruction can be achieved. In summary, the therapeutic spectrum of anteroinferior shoulder instability shows innovative and promising approaches to recreate the integrity of the static stabilizers of the glenohumeral joint using non- operative strategies. In the operative field, the future is dedicated to minimal-invasive procedures with the goal to preserve the integrity of the dynamic stabilizers and lower the morbidity of our patients