Age-related changes of micro-morphological subchondral bone properties in the healthy femoral head.

OBJECTIVE: Alterations in the subchondral bone (SCB) are likely to play a decisive role in the development of osteoarthritis (OA). Since aging represents a major risk factor for OA, the aim of the current study was to assess the microstructural changes of the subchondral bone in the femoral head during aging. DESIGN: Femoral heads and matched iliac crest biopsies of 80 individuals (age 21-99 years) were collected post-mortem. The bone microstructure of the subchondral trabecular bone as well as the cartilage thickness (Cg.Th) and subchondral bone plate thickness (SCB.Th) were quantified using histomorphometry. The different subregions of the SCB were also imaged by quantitative backscattered electron imaging (qBEI) in 31 aged cases to assess the bone mineral density distribution (BMDD). RESULTS: The detected linear decline of bone volume per tissue volume (BV/TV) in the femoral head with aging (Slope, 95% CI: -0.208 to -0.109 %/yr.) was primarily due to a decrease in trabecular thickness (Tb.Th, Slope, 95% CI: -0.774 to -0.343 µm/yr). While SCB.Th declined with aging (Slope, 95% CI: -1.941 to -0.034 µm/yr), no changes in Cg.Th were detected (Slope, 95% CI: -0.001 to 0.005 mm/yr). The matrix mineralization of the subchondral bone was lower compared to the trabecular bone and also decreased with aging. CONCLUSIONS: Regular changes of the SCB during aging primarily involve a reduction of Tb.Th, SCB.Th and matrix mineralization. Our findings facilitate future interpretations of early and late OA specimens to decipher the role of the SCB in OA pathogenesis.

[Diagnostics and treatment of posterior shoulder instability]. / Diagnostik und Therapie der posterioren Schulterinstabilität.

Posterior shoulder instability has a markedly lower incidence than anterior shoulder instability. It has a wide spectrum of clinical symptom manifestations and the overwhelming number of patients lack a traumatic primary dislocation. In addition to a detailed medical history, a specific clinical examination with the help of standardized provocation tests is essential for the diagnostics. For the detection of structural posterior capsule and labral lesions in cases of chronic courses, magnetic resonance imaging (MRI) should be used with an intra-articular contrast agent. Relevant bony defects of the humeral head (reverse Sachs-Hill lesion) are frequent, whereas critical posterior defects of glenoid cavity are relatively rare. Both lesions should be quantified using 3D computed tomography. The choice of therapeutic procedure should be based on the underlying pathology of the defect. Conservative therapy is useful in patients with scapular dyskinesis, voluntary dislocation and pathological muscle patterning. In isolated soft tissue pathologies, arthroscopic labrum fixation and capsule plication are the standard treatment. In the case of insufficient soft tissue relations or critical posterior glenoid defects, bony stabilization of the glenoid using an iliac crest bone graft is the recommended therapy.

Results of an open posterior bone block procedure for recurrent posterior shoulder instability after a short- and long-time follow-up.

PURPOSE: The aim of the present study was to analyse and compare the clinical and radiological results after open posterior bone block procedure at long- (LT) and short-term (ST) follow-up. The hypothesis was that placement of a bone block at the posterior glenoid rim in a technique of extending the glenoid surface will create permanent joint stability even in cases with hyperlaxity without a clinically relevant loss of motion or increase in osteoarthritis. METHODS: Fifteen consecutive shoulders with recurrent posterior dislocation were evaluated clinically and radiologically. The Rowe score, Western Ontario Shoulder Index, Walch-Duplay score and the Constant-Murley score were used for clinical evaluation. The patients were categorized according to their follow-up period as either ST follow-up (min 12 months) or LT follow-up (min 42 months). RESULTS: The clinical results showed no significant difference between ST (9) and LT (6) with good to very good overall results in the subjective as well as the objective scores (CS, RS, WDS). At LT, most patients felt mild to minor pain under strain. The difference in pain between the groups was not significant. Active ranges of motion and strength assessments were normal in all cases. In one case, recurrent dislocations occurred after bone graft resorption 6 months post-operatively. Only one patient presented mild osteoarthritis, without further progress at follow-up. CONCLUSION: The open posterior bone block procedure can be a successful treatment option for recurrent posterior shoulder instability at ST and LT follow-up. This series showed a low rate of recurrent dislocations without development or progression of osteoarthritis. Since soft tissue procedures do not always provide satisfying results, the posterior bone block augmentation presents a reliable technique for the treatment of symptomatic posterior instability. LEVEL OF EVIDENCE: Case Series, Treatment Study, Level IV.

The biomechanical influence of the deltotrapezoid fascia on horizontal and vertical acromioclavicular joint stability.

INTRODUCTION: Many studies have investigated the biomechanical influence of the acromioclavicular (AC) and coracoclavicular (CC) ligaments on the stability of the acromioclavicular joint (ACJ). It has been shown that augmentation of the CC ligaments alone can result in residual horizontal instability. Our hypothesis was that the DTF would have a significant stabilizing effect on horizontal ACJ stability. MATERIALS AND METHODS: In a biomechanical in vitro study a sequential injury of the ACJ was created on eight shoulders from full body, which were placed in an upright sitting position. The translation and rotation of the clavicle were measured in relation to the acromion using an optical navigation system in various states during thoracic-humeral elevation, abduction, and horizontal adduction. The three states were: an intact shoulder, complete sectioning of the AC ligaments, and a circular lesion of the DTF. RESULTS: Compared to the intact state we found a significant increase in anterior rotation of the clavicle of 1.11° (p = 0.012) and a tendency in lateral translation of 2.71 mm (p = 0.017) in relation to the acromion, with a combined lesion of AC ligaments and DTF. No significant differences were found between the intact state and the isolated dissected AC ligaments as well in adduction as elevation. CONCLUSION: A combined lesion of the AC ligaments and the DTF resulted in a quantitatively small but significant increase in anterior rotation and a tendency in lateral translation of the clavicle in relation to the acromion. These differences were quantitatively small, so that the clinical relevance of the stabilization effect of combined AC ligaments and DTF injuries is questionable.

[Stability versus mobility of the shoulder. Biomechanical aspects in athletes]. / Stabilität versus Mobilität der Schulter. Biomechanische Aspekte beim Sportler.

The demand profile of athletes shoulders is high. On the one hand the shoulder has to provide a maximum active range of motion that allows rapid movements of the arm and on the other hand it has to be sufficiently stabilized to decelerate rapid movements and to neutralize the resulting translational forces. Two general types of instability can be differentiated in athletes shoulders: the macroinstability typically occurring in athletes involved in contact sports and the microinstability occurring in athletes involved in overhead sports.Repetitive abduction and external rotation movements of athletes involved in overhead sports lead to adaptation of the glenohumeral joint capsule and ligaments. The anterior capsule becomes stretched while the posterior capsule develops tightness. These adaptations can result in an anterior microinstability as well as posterosuperior impingement (PSI) which implicates a pathological contact of the posterosuperior rotator cuff with the posterior glenoid and which is also associated with SLAP lesions. In contrast the shoulders of swimmers are prone to anterosuperior impingement because the arm stroke involves a forceful combined anteflexion, adduction and internal rotation of the arm.The macroinstability of contact athletes is caused by sufficient trauma and characterized by a structural lesion of capsulolabral or bony lesion. While the empirical recurrence risk of young contact athletes is already high, it can be further impaired by bony defects of the glenoid. In suspected cases, critical glenoid defects should be quantified by computed tomography (CT) scans and treated by bony augmentation of the glenoid.

The stabilization effect of the conjoint tendon in reverse total shoulder arthroplasty.

BACKGROUND: Numerous factors determine stability of reverse total shoulder arthroplasty. The effect of the conjoint tendon in relation to stability remains unknown. In this biomechanical study, we evaluated the influence of the conjoint tendon on the anterior stability of reverse total shoulder arthroplasty with a hemispherical glenosphere and a glenosphere with 9 mm lateralisation. METHODS: A reverse total shoulder arthroplasty was implanted in 6 human cadaveric shoulders. The anterior stability was evaluated using a shoulder simulator. Two conditions, intact and dissected conjoint tendon, and 2 component configurations, a hemispherical glenosphere and a glenosphere with 9 mm lateralisation, were tested in each specimen. Testing of anterior stability was performed in 30° and 60° of abduction, with 0° and 30° of external rotation in the glenohumeral joint. FINDINGS: The conjoint tendon showed a significant influence on the anterior stability with a hemispherical glenosphere in 30° and 60° with neutral rotation (p = 0.028) as well as 30° abduction with 30° (p = 0.028) external rotation. The 9 mm lateralised glenosphere stabilized significantly reverse total shoulder arthroplasty with resected conjoint tendon compared to the hemispherical glenosphere with resected conjoint tendon (p = 0.028). INTERPRETATION: In a biomechanical setting the conjoint tendon has a stabilizing influence on the anterior stability of the reverse total shoulder arthroplasty with a hemispherical glenosphere in an abducted arm position, but this stabilizing effect was not seen with the lateralised glenosphere. The single influence of the lateralisation of the glenosphere on anterior stability was shown in cases of resected conjoint tendon.

Transfer of the long head of biceps to the conjoint tendon. A biomechanical study.

BACKGROUND: Tenodesis of the long head of biceps has been intensively investigated and various surgical options exist. The aim of this biomechanical study was to compare the maximum strength of two different techniques for biceps tenodesis. Our hypothesis was that the two procedures have the same biomechanical properties. METHODS: We performed the two different tenodesis techniques using 12 fresh frozen shoulders divided into two groups of six. In the first group, the biceps was transferred to the conjoint tendon. In the second group, an intraossous suprapectoral tenodesis was performed. After a preload of 10 N, cyclical loading with a maximum of 60 N and 100 N with 100 cycles and 0.5 Hz was applied to the tendons for both groups. An axial ultimate loading to failure was conducted subsequently. RESULTS: No significant differences were found in age, bone mineral density, or weight between the two groups. During the cyclical loading with 60 N, one slippage of the tendon was observed in the suprapectoral group. The mean ultimate load to failure was 294.15N in the transposition group and 186.76 N in the suprapectoral group, but this difference was not significant (P=0.18). INTERPRETATION: The biomechanical results demonstrated equal biomechanical properties postoperatively for both transposition of the tendon and the current standard suprapectoral tenodesis procedure. The transposition can be performed as a primary or a salvage procedure in order to potentially reduce the proportion of patients with persistent postoperative bicipital groove pain and is comparable in strength to a standard tenodesis.

Prospective study of injury in volleyball players: 6 year results.

BACKGROUND: The volleyball game has a high complexity and thus entails a lot of strain to the players. Due to this high and different training and competition strain comprehensive and individual training plans should be developed with competing training objectives in order to prevent injuries. OBJECTIVE: The aim of the study was to analyse prospectively over six seasons the acute and overuse injuries of a German male professional volleyball team. METHODS: The study included 34 male national league players from season the 2007/08 to 2012/13. All players received a sport medicine examination and a functional diagnosis before each season. Based on the results the players received an individual training plan. RESULTS: The players suffered 186 injuries. The prevalence of acute injuries was 1.94 per player and overuse injuries 0.64 per player. The incidence of acute injuries was 3.3/1000 h volleyball and overuse injuries 1.08/1000 h volleyball. The largest number of injuries was found in the spine. The players had most likely minor injuries. The players had significantly fewer injuries in their second season (1.92) than in their first season (3.25; p= 0.004). CONCLUSION: It could be concluded that volleyball is a sport with a relative low prevalence of injuries compared to other team sports. The prevalence of injury is 2.58 per player. Due to an injury a player dropped out 16.91 days per season. An individual training program seems to reduce the incidence of injury.

[Arthroscopic posterior shoulder stabilization with an iliac bone graft and capsular repair]. / Arthroskopische posteriore Schulterstabilisierung mit Knochenblock und Kapselrekonstruktion.

OBJECTIVE: Arthroscopic posterior shoulder stabilization with an iliac bone graft and capsulolabral repair, which should combine the pre-existing open procedure with the advantages of improved arthroscopic visualization. INDICATIONS: Posterior instability with concomitant pathologies (e.g. capsular insufficiency, posterior Bankart lesion, posterior glenoid dysplasia) and recurrent posterior instability after failed soft tissue reconstruction. CONTRAINDICATIONS: Instability osteoarthritis, locked posterior shoulder dislocation, large reverse Hill-Sachs lesion, extended posterior defect of the glenoid. SURGICAL TECHNIQUE: After arthroscopic evaluation of the shoulder joint and treatment of concomitant pathologies, a tricortical bone graft is harvested from the iliac crest. The posterior capsule is arthroscopically detached from the labrum and the posterior deltoid and rotator cuff are split in line of the muscle fibers. Then the bone graft is positioned and fixed to the posterior scapular neck as an extension of the articular glenoid surface. Thereafter, capsular reconstruction is performed after insertion of suture anchors in the posterior glenoid rim. POSTOPERATIVE MANAGEMENT: During the first 6 weeks 60° of abduction and flexion are permitted without any rotation and full range of motion is developed gradually. Internal rotation is allowed after 8 weeks and return to sports after 12 weeks. RESULTS: For posterior shoulder instability 13 of these operations were performed in our hospital since 2011. Until now, no recurrent instability was observed. After remodelling of the graft, one patient complained about posterior soft tissue irritation so the screws were removed.

[Glenohumeral arthrolysis of the osteoarthritic shoulder in anatomical total shoulder arthroplasty]. / Glenohumerale Arthrolyse der Omarthroseschulter bei anatomischer Schulterprothesenimplantation.

AIM OF THE OPERATION: Pain reduction and improvement of range of motion. INDICATIONS: Primary and secondary osteoarthritis, unsuccessful conservative treatment, limited range of motion with capsular contraction. CONTRAINDICATIONS: General contraindications for anatomical total shoulder arthroplasty. Instability arthritis without capsular contraction. OPERATIVE TECHNIQUE: Deltopectoral approach. Detachment and release of the subscapularis tendon at the lesser tuberosity, incision of the anterior and inferior humeral sided capsule and osteophyte removal, humeral head resection and stem preparation. Glenoid exposure, capsular an labral resection. Glenoid surface preparation and prosthetic component implantation. Anatomical placement of the the humeral head without overstuffing. Implantation of the final humeral stem. Transosseous refixation of the subscapularis tendon. Wound closure. FOLLOW-UP TREATMENT: Abduction brace for 4 weeks. Assisted motion starting the first postoperative day during the first 6 weeks: anteversion/ retroversion 90-0-0°, abduction/ adduction 90-0-20°, internal/external rotation 90-0-individual limitation. Subsequent development of full range of motion. RESULTS: In 2009 and 2010 anatomical total shoulder arthroplasty with glenohumeral arthrolysis was performed in 53 cases. At an average follow up of 32 months the Constant score and range of motion improved significantly. The complication rate was 9%.