[Diagnosis of upper arm, elbow, and proximal lower arm fractures]. / Frakturdiagnostik an Oberarm, Ellenbogen und proximalem Unterarm.

The complex anatomy of the elbow joint enables a wide range of movement and complex functions in everyday and professional life. Typical injuries of this joint include a variety of different pathologies. Due to overlaying structures in plain radiographs, diagnosis of injuries to the elbow joint places high demands on the treating physicians and often needs further diagnostic imaging. The following article will give an overview of the most common of these injuries and their diagnosis.

Four-Strand Core Suture Improves Flexor Tendon Repair Compared to Two-Strand Technique in a Rabbit Model.

Introduction. This study was designed to investigate the influence of the amount of suture material on the formation of peritendinous adhesions of intrasynovial flexor tendon repairs. Materials and Methods. In 14 rabbits, the flexor tendons of the third and the fourth digit of the right hind leg were cut and repaired using a 2- or 4-strand core suture technique. The repaired tendons were harvested after three and eight weeks. The range of motion of the affected toes was measured and the tendons were processed histologically. The distance between the transected tendon ends, the changes in the peritendinous space, and cellular and extracellular inflammatory reaction were quantified by different staining. Results. A 4-strand core suture resulted in significantly less gap formation. The 2-strand core suture showed a tendency to less adhesion formation. Doubling of the intratendinous suture material was accompanied by an initial increase in leukocyte infiltration and showed a greater amount of formation of myofibroblasts. From the third to the eighth week after flexor tendon repair, both the cellular and the extracellular inflammation decreased significantly. Conclusion. A 4-strand core suture repair leads to a significantly better tendon healing process with less diastasis between the sutured tendon ends despite initially pronounced inflammatory response.

The effect of a collagen-elastin matrix on adhesion formation after flexor tendon repair in a rabbit model.

PURPOSE: The outcome of flexor tendon surgery is negatively affected by the formation of adhesions which can occur during the healing of the tendon repair. In this experimental study, we sought to prevent adhesion formation by wrapping a collagen-elastin scaffold around the repaired tendon segment. METHODS: In 28 rabbit hind legs, the flexor tendons of the third and fourth digits were cut and then repaired using a two-strand suture technique on the fourth digit and a four-strand technique on the third digit. Rabbits were randomly assigned to study and control groups. In the control group, the operation ended by closing the tendon sheath and the skin. In the study group, a collagen-elastin scaffold was wrapped around the repaired tendon segment in both digits. After 3 and 8 weeks, the tendons were harvested and processed histologically. The range of motion of the digits and the gap formation between the repaired tendon ends were measured. The formation of adhesions, infiltration of leucocytes and extracellular inflammatory response were quantified. RESULTS: At the time of tendon harvesting, all joints of the operated toes showed free range of motion. Four-strand core sutures lead to significantly less diastasis between the repaired tendon ends than two-strand core suture repairs. The collagen-elastin scaffold leads to greater gapping after 3 weeks compared to the controls treated without the matrix. Within the tendons treated with the collagen-elastin matrix, a significant boost of cellular and extracellular inflammation could be stated after 3 weeks which was reflected by a higher level of CAE positive cells and more formation of myofibroblasts in the αSMA stain in the study group. The inflammatory response subsided gradually and significantly until the late stage of the study. Both the cellular and extracellular inflammatory response was emphasized with the amount of material used for the repair. CONCLUSION: The use of a collagen-elastin matrix cannot be advised for the prevention of adhesion formation in flexor tendon surgery, because it enhances both cellular and extracellular inflammation. Four-strand core sutures lead to less gapping than two-strand core sutures, but at the same time, the cellular and extracellular inflammatory response is more pronounced.

Vascularized Hypothenar Fat Pad Flap in Revision Surgery for Carpal Tunnel Syndrome.

OBJECTIVE: To evaluate the results of the hypothenar fat pad flap in revision surgery for carpal tunnel syndrome (CTS). PATIENTS AND METHODS: We retrospectively analyzed 18 consecutive patients (14 women, 4 men) who had recurrent CTS. The average age was 61 years. All patients had undergone the index carpal tunnel release 5 to 22 months ago. From November 2009 to November 2013, they were treated by decompression of the median nerve and a vascularized hypothenar fat pad flap. The intraoperative findings were assessed as well as the level of pain, recovery of sensory and motor dysfunction, Hoffmann-Tinel sign, nerve conduction studies, grip and pinch strength, and Disability of Hand and Shoulder Questionnaire (DASH) score. All patients were reevaluated at an average of 22 months after revision surgery. RESULTS: After revision surgery, 15 patients reported symptomatic improvement. No patient reported worsening of symptoms. A median DASH score of 18 was reached. Grip strength recovered to 90% of the contralateral side. Overall, 15 patients were satisfied with the result of the operation; 3 did not cope with pain and dysfunction. Recurrence was not found in any case. CONCLUSION: The hypothenar fat pad flap can be used successfully as an adjunct to microsurgical neurolysis for the treatment of recurrent CTS secondary to perineural scarring, although a functional deficit remains in some patients.

Minimum cement volume required in vertebral body augmentation--A biomechanical study comparing the permanent SpineJack device and balloon kyphoplasty in traumatic fracture.

BACKGROUND: Minimally invasive treatment of vertebral fractures is basically characterized by cement augmentation. Using the combination of a permanent implant plus cement, it is now conceivable that the amount of cement can be reduced and so this augmentation could be an attractive opportunity for use in traumatic fractures in young and middle-aged patients. The objective of this study was to determine the smallest volume of cement necessary to stabilize fractured vertebrae comparing the SpineJack system to the gold standard, balloon kyphoplasty. METHODS: 36 fresh frozen human cadaveric vertebral bodies (T11-L3) were utilized. After creating typical compression wedge fractures (AO A1.2.1), the vertebral bodies were reduced by SpineJack (n=18) or kyphoplasty (n=18) under preload (100N). Subsequently, different amounts of bone cement (10%, 16% or 30% of the vertebral body volume) were inserted. Finally, static and dynamic biomechanical tests were performed. FINDINGS: Following augmentation and fatigue tests, vertebrae treated with SpineJack did not show any significant loss of intraoperative height gain, in contrast to kyphoplasty. In the 10% and 16%-group the height restoration expressed as a percentage of the initial height was significantly increased with the SpineJack (>300%). Intraoperative SpineJack could preserve the maximum height gain (mean 1% height loss) better than kyphoplasty (mean 16% height loss). INTERPRETATION: In traumatic wedge fractures it is possible to reduce the amount of cement to 10% of the vertebral body volume when SpineJack is used without compromising the reposition height after reduction, in contrast to kyphoplasty that needs a 30% cement volume.

Acromioclavicular joint dislocations: radiological correlation between Rockwood classification system and injury patterns in human cadaver species.

INTRODUCTION: The classification system of Rockwood and Young is a commonly used classification for acromioclavicular joint separations subdividing types I-VI. This classification hypothesizes specific lesions to anatomical structures (acromioclavicular and coracoclavicular ligaments, capsule, attached muscles) leading to the injury. In recent literature, our understanding for anatomical correlates leading to the radiological-based Rockwood classification is questioned. The goal of this experimental-based investigation was to approve the correlation between the anatomical injury pattern and the Rockwood classification. MATERIALS AND METHODS: In four human cadavers (seven shoulders), the acromioclavicular and coracoclavicular ligaments were transected stepwise. Radiological correlates were recorded (Zanca view) with 15-kg longitudinal tension applied at the wrist. The resulting acromio- and coracoclavicular distances were measured. RESULTS: Radiographs after acromioclavicular ligament transection showed joint space enlargement (8.6 ± 0.3 vs. 3.1 ± 0.5 mm, p < 0.05) and no significant change in coracoclavicular distance (10.4 ± 0.9 vs. 10.0 ± 0.8 mm). According to the Rockwood classification only type I and II lesions occurred. After additional coracoclavicular ligament cut, the acromioclavicular joint space width increased to 16.7 ± 2.7 vs. 8.6 ± 0.3 mm, p < 0.05. The mean coracoclavicular distance increased to 20.6 ± 2.1 mm resulting in type III-V lesions concerning the Rockwood classification. CONCLUSIONS: Trauma with intact coracoclavicular ligaments did not result in acromioclavicular joint lesions higher than Rockwood type I and II. The clinical consequence for reconstruction of low-grade injuries might be a solely surgical approach for the acromioclavicular ligaments or conservative treatment. High-grade injuries were always based on additional structural damage to the coracoclavicular ligaments. Rockwood type V lesions occurred while muscle attachments were intact.

Intramedullary nail versus volar plate fixation of extra-articular distal radius fractures. Two year results of a prospective randomized trial.

BACKGROUND: Intramedullary techniques for stabilization of displaced distal radius fractures are now available. Purported benefits include limited soft tissue dissection while affording sufficient stability to allow early wrist motion. The primary null hypothesis of this randomized trial is that there is no significant difference with respect to functional outcome, pain and disability between patients treated with either 2.4-mm volar locking plate fixation or intramedullary nail fixation of unstable dorsally displaced extra-articular fractures of the distal radius. METHODS: We conducted a single-centre, parallel-group trial, with unrestricted randomization. Patients with dorsally displaced extra-articular distal radius fractures were randomized to receive volar locking plate (n=72) fixation or intramedullary nailing (n=80). The outcome was measured on the basis of the Gartland and Werley and Castaing score; the pain level; the range of wrist motion; the rate of complications; and radiographic measurements including volar tilt and ulnar variance. Clinical and radiographic assessment was performed at 8 weeks, 6 months, 1 year and 2 years after the operation. RESULTS: There were no significant differences between groups in terms of range of motion, grip strength or the level of pain during the entire follow-up period (p>0.05). There was no significant difference between treatment groups with respect to volar tilt or ulnar variance (p>0.05). There was no significant difference in the complication rate between groups (p>0.05). CONCLUSIONS: The present study supports the view that intramedullary nail fixation and volar plate fixation for the treatment of displaced extra-articular distal radius fractures have equivalent radiographic and functional outcomes. LEVEL OF EVIDENCE: Level I therapeutic study.

Angular stable multiple screw fixation (Targon FN) versus standard SHS for the fixation of femoral neck fractures.

OBJECTIVE: Head-preserving fracture care especially for the elderly may be complicated by acetabular screw penetration, cut out, delayed union or femoral head necrosis. The following comparative study analyses whether a new angular stable device may overcome these shortcomings. MATERIAL AND METHODS: The Targon FN plate (BBraun/Aesculap, Germany) employs up to four angular stable telescoping screws for the fixation of the head fragment. In a prospective study patients with displaced and undisplaced intracapsular femoral neck fractures where treated by closed reduction and fracture fixation using either the Targon FN implant or a standard sliding hip screw (SHS). Patients were followed up clinically, radiographically and via telephone at a mean of follow-up time of 15.5 months. RESULTS: Fifty-two patients (mean age: 67 years) with femoral neck fractures were treated with either Targon FN (27 patients) or SHS (25 patients). Time for surgery did not differ within the two groups (56 min Targon FN vs. 55 min SHS). Eight patients with SHS (32%) and four patients (15%) with Targon FN experienced cut out of the lag screw and received hip replacement (p<0.05). Implant failure occurred after a mean of 1.8 months after SHS and 6.0 months after Targon FN implantation. Final radiographs revealed substantial subsidence in both groups (5.0mm Targon FN; 9.8mm SHS, p=0.055) with a clear trend to less subsidence for the Targon FN group. Furthermore, asymmetrical telescoping of the lag screws occurred in 30% (n=8), complete depletion of telescoping distance in 11% (n=3) in the Targon FN group. Functional assessment using the HHS assessment tool, however, presented with slightly better results for the SHS treatment (87.7 ± 13.9) when compared to Targon FN fixation (69.5 ± 14.5). CONCLUSIONS: The study revealed less subsidence of the head fragment, lower cut out rate and a lower rate of conversion to hemiarthroplasty after Targon FN fixation in comparison to a standard SHS fixation in a small number of patients with hip fractures. However, this was not accompanied by functional limitations in the SHS group.

Antithrombin reduces inflammation and microcirculatory perfusion failure in closed soft-tissue injury and endotoxemia.

BACKGROUND: Closed soft-tissue trauma leads to activation of the coagulation cascade and is often complicated by systemic inflammation and infection. Previous investigations have shown potent anti-inflammatory properties of antithrombin. We herein report on the action of antithrombin on skeletal muscle injury in experimental endotoxemia. MATERIALS AND METHODS: By using a pneumatically driven computer-controlled impact device, closed soft-tissue trauma was applied on the left hind limb of pentobarbital-anesthetized rats. Six hours later, endotoxemia was induced by intraperitoneal injection of Escherichia coli lipopolysaccharide. An equivalent volume of physiological saline was given in controls. At the same time point, treatment of animals was started by intravenous injection of antithrombin (250 IU/kg body weight) or vehicle solution. Twenty-four hours after trauma, the extensor digitorum longus muscle was microsurgically exposed and analyzed by means of high-resolution multifluorescence microscopy. RESULTS: Traumatic soft-tissue injury with additional endotoxemia was characterized by nutritive perfusion failure (functional capillary density: 379±20cm/cm;), tissue hypoxia (nicotinamide adenine dinucleotide autofluorescence: 77±4 aU), and enhanced leukocyte-endothelial cell interaction (773±35 cells/mm;). Therapeutic intervention with antithrombin 6 hrs after trauma restored nutritive perfusion and tissue oxygenation (functional capillary density: 469±22cm/cm; nicotinamide adenine dinucleotide autofluorescence: 61±5 aU [p < 0.05]) and reduced inflammatory leukocyte adherence (237±20 cells/mm; [p < 0.05]) toward values found in nontraumatized controls (functional capillary density: 573±13cm/cm; nicotinamide adenine dinucleotide autofluorescence: 56±2 aU; leukocyte adherence: 204±20 cells/mm;). CONCLUSION: Antithrombin ameliorates microcirculatory dysfunction and tissue injury in traumatized animals during endotoxemia. Furthermore, a reduced inflammatory cell response helps to prevent leukocyte-dependent secondary tissue injury.

A pan-caspase inhibitor reduces myocyte apoptosis and neuropathic pain in rats with chronic constriction injury of the sciatic nerve.

BACKGROUND: Chronic constriction injury is a widely used model for neuropathic pain in rats. It presents with symptoms resembling human neuropathic pain, such as spontaneous pain, hyperalgesia, and allodynia. Recently, myocyte apoptosis was found in neuropathic rats as a possible promoter of pain and motor dysfunction. Our aim in this study was to demonstrate whether muscle cell apoptosis contributes to neuropathic pain in this animal model. METHODS: To clarify this issue, we examined pain, nutritive perfusion, and inflammation in muscle tissue as well as myocyte apoptosis in rats with neuropathic pain established by chronic constriction injury of the sciatic nerve. Animals received either the pan-caspase inhibitor zVAD (OMe)-fmk (n = 5) or equivalent volumes of vehicle (n = 6). Sham-operated rats served as controls (n = 6). RESULTS: At day 4 after nerve ligation, there were no signs of perfusion failure or muscle tissue inflammation in all experimental groups. However, animals treated with the vehicle had marked myocyte apoptosis, which was found almost completely blocked in zVA-Dtreated animals. The zVA-Dtreated animals presented with a significant reduction of pain upon heat, cold, and mechanical stimulation comparable with values found in sham controls. CONCLUSIONS: Myocyte apoptosis possibly contributes to thermal and mechanical allodynia in this experimental model for neuropathic pain. The development of neuropathic pain symptoms did not depend on disturbances in microcirculation or muscle tissue inflammation.

Reliability and consequences of intraoperative 3D imaging to control positions of thoracic pedicle screws.

INTRODUCTION: The insertion of thoracic pedicle screws (T1-T10) is subject to a relevant rate of malplacement. The optimum implantation procedure is still a topic of controversial debate. Currently, a postoperative computed tomography is required to evaluate the screw positions. The present study was undertaken to clarify whether intraoperative 3D imaging is a reliable method of determining the position of thoracic pedicle screws. METHODS: This prospective study involved 40 consecutive patients with thoracic spinal injuries, with intraoperative 3D scans being performed to determine the positions of 240 pedicle screws in T1-T10. The results of the 3D scans were compared with the findings of postoperative CT scans, using a clinical classification system. RESULTS: The positions of 204 pedicle screws could be viewed by means of both 3D and CT scans and the results compared. The 3D scans achieved a sensitivity of 90.9 % and a specificity of 98.8 %. The rate of misclassification by the 3D scans was 2.5 %. Nine pedicle screws were classified as misplaced and their position corrected intraoperatively (3.8 %). No screws required postoperative revision. CONCLUSIONS: Performing an intraoperative 3D scan enables the position of thoracic pedicle screws to be determined with sufficient accuracy. The rate of revision surgery was reduced to 0 %.

Hook plate fixation for acromioclavicular joint separations restores coracoclavicular distance more accurately than PDS augmentation, however presents with a high rate of acromial osteolysis.

INTRODUCTION: Hook plate fixation of acromioclavicular (AC) joint separations carries the disadvantage of compulsory implant removal, occasional implant fatigue and secondary loss of reduction. This study compares the clinical and radiological outcome of a new polyaxial angular stable hook plate (HP) with absorbable polydioxansulfate (PDS) sling. MATERIALS AND METHODS: Between 2002 and 2009, out of a consecutive series of 81 patients with symptomatic Rockwood type V lesions 52 patients received clinical and radiographic follow-up (HP: n = 27; PDS: n = 25). HP patients were prospectively analyzed and retrospectively compared with the PDS group. Radiological follow-up included comparative coraco- and acromioclavicular distance (CCD/ACD) measurements as percentage of the uninjured shoulder. For clinical follow-up a standardized functional shoulder assessment with Constant Score, DASH Score, Taft Score and a self-report questionnaire including the visual analog scale (VAS) was carried out. RESULTS: Direct postoperative radiographs showed an overcorrection of CCD in the HP group (-4.4% of the uninjured side) and failure of anatomic correction in the PDS group (+11.0%). After implant removal, CCD increased in the HP group extensively to 16.7% (overall loss of reduction: 21.1%) and 23.9% in the PDS group. Redisplacement (100% increase of CCD) occurred in five cases (HP: 2, PDS: 3) and partial loss of reduction in four cases of each group. Comparing functional results no differences could be seen between both the groups (Constant-Score HP: 91.2 points, PDS: 94.6 points; Taft-Score HP: 9.4 points, PDS: 10.0 points). The DASH-Score revealed better results for PDS group (3.4 points, HP: 8.0 points). Signs of acromial osteolysis appeared in five cases (18.5%) in HP group. There was no case of implant failure. The X-rays of six patients (HP: 4, PDS: 2) showed AC-joint-osteoarthritis. CONCLUSION: Hook plate fixation employing a polyaxial angular stable plate finally restores the coracoclavicular distance more accurately than augmentation with a PDS sling. Although in HP group no implant failure occurred, major disadvantages are initial overcorrection and acromial osteolysis. Both have no influence on final functional results.

Ebselen reduces inflammation and microvascular perfusion failure after blunt skeletal muscle injury of the rat.

BACKGROUND: Soft tissue trauma induces an local inflammatory response and yields a microvascular perfusion failure due to trauma-induced oxidative stress. Using high-resolution multifluorescence microscopy, we herein report on the efficiency of treatment with the oxygen radical scavenger ebselen to improve compromised perfusion of traumatized muscle tissue and to minimize secondary tissue damage. METHODS: By using a pneumatically driven computer-controlled impact device, closed soft tissue trauma of the left hind limb was induced in pentobarbital-anesthetized rats that received either ebselen (30 mg/kg body weight, intraperitoneally) or equal volumes of the vehicle dimethyl sulfoxide (DMSO). In an additional series of animals, ebselen or DMSO were applied without soft tissue trauma. RESULTS: Ebselen restored microcirculatory impairment within the injured muscle, as given by values of nutritive perfusion (763 +/- 44 cm/cm2), nicotinamide adenine dinucleotide levels (56 +/- 3 aU) and inflammatory cell interaction (leukocytes: 226 +/- 31 mm(-2)) at 24 hours after trauma, being not different to those found in noninjured muscle tissue of controls. In contrast, skeletal muscle in DMSO-treated animals revealed persistent perfusion failure (564 +/- 32 cm/cm2) with tissue hypoxia (nicotinamide adenine dinucleotide 75 +/- 11 aU) and enhanced endothelial interaction of leukocytes (383 +/- 18 mm(-2)) at 24 hours after trauma. CONCLUSIONS: Treatment of skeletal muscle soft tissue trauma with the glutathione peroxidase mimic ebselen is highly effective in restoration of disturbed microcirculation. Moreover, reduced inflammatory cell response helps to prevent leukocyte-dependent secondary tissue injury.

Genetic control of leucocyte--endothelial cell interaction in collagen-induced arthritis.

OBJECTIVE: Despite considerable work on defining disease pathways, several aspects of collagen-induced arthritis (CIA) remain poorly defined, in particular those contributing to the initiation phase of the disease. It is thought that in CIA the activation of circulating leucocytes, their interaction with the endothelial lining followed by subsequent transendothelial migration and infiltration into tissue represents the first and determining step in a complex sequence of processes mediating tissue injury. In this study we attempted to define the genetic basis of this stage of disease using genetic linkage studies, in-vivo imaging and expression profiling. METHODS: A genome scan with 132 informative markers was performed on 155 (DBA/1JxFVB/N) F2 mice. Linkage analysis was performed by combining genotyping data from the genome scan and the phenotypic data of leucocyte adherence, leucocyte rolling fraction, functional capillary density, centre line red blood cell velocity and capillary width as well as the expression level of the selected genes Cd44, Il13ralpha1, Ccr3, Defb3, Sele, Sell, Selp, Xcl1, Il1beta, Tnfalpha and Ifngamma as traits. RESULTS: Multiple classic quantitative trail loci (QTL) controlling leucocyte-endothelial cell interactions were identified on chromosomes 8 and 17 as well as expression QTL controlling the expression of several differentially expressed adhesion molecules and cytokines on chromosomes 1, 2, 5, 6, 7, 8, 12, 15, 16 and 17. CONCLUSION: The study describes for the first time QTL controlling the CIA initiating leucocyte-endothelial cell interaction.

Intraoperative position determination of bone cement trocars by 3-dimensional imaging in patients with osteoporotic vertebral fractures.

STUDY DESIGN: A prospective diagnostic study to evaluate the use of intraoperative 3-dimensional (3D) imaging. OBJECTIVE: To evaluate the accuracy of an intraoperative 3D imaging predicting trocar positions in osteoporotic fractured vertebral bodies before cement injection. SUMMARY OF BACKGROUND DATA: Malpositioned needles in vertebroplasty and kyphoplasty increase the risk of extravertebral cement leakage and the associated complications. This study was intended to clarify whether the position of trocars can adequately be determined before the cement application by an intraoperative 3D imaging. METHODS: Between August 2006 and July 2008 the positions of 84 trocars in 42 fractured vertebrae between T11 and L5 were measured by intraoperative 3D imaging before injection of the cement. The external diameter of the needles was 9 to 10 G. The positions of the trocars were classified in the axial plane by a new classification system. RESULTS: Forty 3D scans covered 84 injection cannulae in 42 fractured vertebral bodies. The average duration of the entire scanning procedure was 7.1 minutes. All 3D scans could be evaluated with adequate degree of certainty. Intraoperative evaluation of the 3D scans showed 78 correct needle positions. Two trocars were in an acceptable lateral malposition. There were 4 medial malpositions that required revision. In total, 4.8% of the trocars were positioned not acceptably. Postoperative computed tomography was performed in 17 patients. The positions of 34 needles determined by computed tomography conformed 100% to the results of the 3D scans. CONCLUSIONS: It is possible to reliably determine the position of trocars in vertebral bodies with the aid of an intraoperative 3D scan. This can lead to a reduction in the morbidity rates associated with puncture errors in kyphoplasty and vertebroplasty. The amount of time required is small. The increased radiation exposure is acceptable.

Microcirculatory sequelae of the rotator cuff after antegrade nailing in proximal humerus fracture.

INTRODUCTION: Antegrade nailing allows a stable fixation and, thus, an early functional after treatment in proximal humerus fractures. Since the surgical procedure in antegrade humeral nailing requires a split of the supraspinatus tendon, the question arises whether the surgical approach causes microcirculatory dysfunction of the tendon. MATERIALS AND METHODS: A total of 15 consecutive patients suffering from proximal humerus fractures were enrolled. During the implantation of an antegrade humerus nail, microvascular perfusion of the supraspinatus tendon was directly visualized after the exposition and stabilization of the fracture using the OPS-imaging technique. RESULTS: Immediately after exposure, the nutritive perfusion showed physiological values of tendon microcirculation. After implanting antegrade humeral nails, the perfusion of the supraspinatus tendon reduced markedly. Capillary width was unaffected by the surgical procedure. CONCLUSION: The trauma leading to proximal humerus fracture causes no fundamental impairment of nutritive perfusion of the rotator cuff. Whereas the implantation of an antegrade humerus nail, which necessarily includes a splitting of the rotator cuff, nearly halves the functional capillary density of the supraspinatus tendon. Even though this effect seems to be reversible, the surgical dissection of the supraspinatus tendon should be performed in a soft tissue sparing way.