Arm Squeeze Test: a new clinical test to distinguish neck from shoulder pain

Purpose

Objective of this study is to evaluate the diagnostic values of the Arm Squeeze Test. The test consists in squeezing the middle third of the upper arm.

Methods

1,567 patients were included in this study. Diagnosis of cervical nerve root compression or shoulder disease was clinically formulated and confirmed with imaging before performing test. 350 healthy volunteers were recruited as controls. The test was positive when score on a VAS Scale was 3 points or higher on squeezing the middle third of the upper arm compared to acromioclavicular (AC) joint and anterolateral-subacromial area.

Results

Patients were subdivided as follows: 903 with rotator cuff tear, 155 with shoulder adhesive capsulitis, 101 with AC joint arthropathy, 55 with calcifying tendonitis, and 48 affected by glenohumeral arthritis. The study sample included 305 patients with cervical nerve root compression from C5 to T1 with shoulder radicular pain. The test was positive in 295/305 (96.7 %) of patients with cervical nerve root compression, compared to 35/903 (3.87 %), 3/155 (1.93 %), 0/101 (0 %), 1/55 (1.81 %) and 4/48 (8.33 %) of those with rotator cuff tear, adhesive capsulitis, AC arthropathy, calcifying tendonitis and glenohumeral arthritis, respectively. A positive result was obtained in 14/350 asymptomatic subjects (4 %). If patients with cervical nerve root compression were compared to controls and patients with shoulder diseases, the test had sensitivity of 0.96 and specificity from 0.91 to 1.

Conclusions

The Arm Squeeze Test may be useful to distinguish cervical nerve root compression from shoulder disease in case of doubtful diagnosis. A positive result to this test may lead to cervical etiology of the shoulder pain.     

Modulare inverse Frakturendoprothese bei nichtrekonstruierbarer Humeruskopffraktur des alten Menschen

Objective

Primary endoprosthetic joint replacement in non-reconstructable proximal humeral fracture in the elderly. Alternative to fracture hemi-endoprosthesis with resorption of tuberosities and secondary rotator cuff insuffiency which leads to unsatisfying functional results.

Indications

Non-reconstructable proximal humeral fracture in mainly old patients with osteoporotic bone, multifragment tuberosity fracture and degenerative rotator cuff lesion.

Contraindications

Patient not fit for surgery, pre-existing shoulder infection or sepsis, severe general medical condition, nerve damage (axillay nerve, Plexus)

Surgical technique

Deltopectoral or delta-split approach. Removal of head fragments. Reinforcement of tuberosities and exposure of glenoid. Implantation of the metaglene and fixation of glenosphere after removal of labrum and capsule. Reaming of humeral shaft and cementing of the prosthesis stem. The retroversion and height of the reverse central part then can be adjusted freely. The tuberosities can be fixed with suture at the middle part. With a titanium cable an additional compression osteosynthesis of the tuberosities can be done by direct pressing on the osseoinductive coated central part.

Postoperative management

Positioning of the arm on an abduction pillow for 4 weeks, then active exercise treatment until week 6. Free movement exercise under guidance for 6 months.

Results

Multicentre study with 43 patients (40 women, 3 men), average age 79.8 years (range 66.9–95.8 years), 36 patients with 4-part-fracture according to Neer classification. To date, follow-up of 24 patients after at least 24 months, 9 patients lost to follow-up. Mean Constant Score 65.5 points, age and gender corrected Constant Score 96.7?%. Visual Analog Scale (VAS) for pain 1.9. VAS for subjective satisfaction 7.5. Mean American Shoulder and Elbow Surgeons Shoulder Score (ASES) 72.8 points. Mean active range of motion: flexion 142.3°, abduction 135.9°, external rotation 18.6°, internal rotation 47°, the radiological evaluation so far did not show any signs of scapular notching. Complications: One dislocated acromion fracture.     

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%.     

Fixed and functional decentering of the head of the humerus in patients with omarthrosis

Aim: To determine whether in patients with specific types of osteoarthritis of the shoulder not only a fixed but also a functional decentering of the humeral head exist. Method: The shoulder joints of 10 healthy volunteers and of 16 patients with osteoarthritis of the shoulder were examined in various arm-positions, using an open MR scanner. After segmentation, 3D reconstruction of the scapula and humerus were performed and the position of the midpoint of the humeral head calculated relative to the center of mass of the glenoid cavity. Results: At 30° of abduction, 4 of 16 patients demonstrated a fixed posterior (12.9±2.8 mm) position and 8 (all patients with cuff-arthropathy) a fixed superior (6.6±2.6 mm) position of the humeral head. At 90° of abduction the patients showed a significant (p<0.001) combined decentering in the superior and posterior direction as compared to the healthy shoulders (functional decentering). Conclusions: This study demonstrates, that in most of the patients with osteoarthritis of the shoulder, a significant functional decentering occurred during abduction and external rotation, even if they showed no fixed decentering of the humeral head at 30° of abduction.     

Combined fluoroscopic and ultrasound guided cervical nerve root injections

Purpose

To assess the technical feasibility, safety and initial clinical efficacy of a combined ultrasound and fluoroscopy imaging approach to cervical nerve root blocks. Fluoroscopic guided cervical transforaminal and selective nerve root injections are often used in the investigation or treatment of radicular symptoms, although rare but serious complications including death have been reported. We report a combined technique developed to increase safety of selective nerve root injections, including the safety and early efficacy of this novel technique in our initial patient cohort.

Methods

We retrospectively reviewed a consecutive cohort of injections performed in 149 patients by a single consultant radiologist between December 2010 and August 2012. For all patients the outcome was assessed both immediately following the procedure and at six weeks. Primary outcome was reduction in radicular symptom level. Duration of symptoms were also assessed and all complications were recorded.

Results

One hundred and forty nine patients underwent injection at either one or two cervical levels. No patients experienced any complications during the follow-up period, and 72 % had an initial positive response to the injection. Of these, 42 % were discharged to the care of their General Practitioner, 23 % went on to have surgery, 18 % were actively monitored in a specialist clinic, 10 % were referred to our pain management service and 4 % had the injection repeated after symptoms recurred.

Conclusion

Using this combined image guided technique cervical nerve root blocks appear both safe and effective in the investigation and management of radicular symptoms from the cervical spine.

     

The Humerusblock NG: a new concept for stabilization of proximal humeral fractures and its biomechanical evaluation

Background

The Humerusblock NG represents a new semi-rigid angular stable fixation device for minimally invasive stabilization of proximal humeral fractures. This study evaluates the function and stability of the Humerusblock NG and its biomechanical properties on the basis of two different fracture models under cyclic loading.

Methods

Six fresh frozen human humeri were tested in a dynamic shoulder joint abduction motion test bench, simulating abduction between 15° and 45°. A stable wedge fracture with intact medial hinge and an unstable fracture with 5-mm gap were loaded for 500 cycles. Radiological measurement of implant migration was performed.

Results

The stable fracture model showed a slow constant fracture settling. The unstable fracture model showed initial fracture settling with closure of the medial fracture gap during the first 20 cycles. Thereafter, a slow constant settling of the fracture was measured comparable to the stable fracture model. Maximum varus tilt was 3.17° for the stable and 3.68° for the unstable fracture pattern. Radiological analysis showed no change in the tip apex distance and a significant settling of the implants fixation pins in the unstable fracture model. None of the specimen failed during the testing.

Conclusion

The Humerusblock NG allows for angular stable dynamic fixation of two-part proximal humeral fractures. It enables closure of the fracture gap and maintains fracture compression during loading, a concept already established in the stabilization of femoral neck fractures (dynamic hip screw). Clinical trials will be necessary to evaluate the value of this device in daily practice.

Level of evidence

Basic science study.     

„Impingement“ der posterolateralen Humerusplatte

Background

Double-plate osteosynthesis has to be considered the gold standard for treating complex distal humeral fractures in adults. Impingement of the posterolateral plate with the olecranon or the radial head in extension of the elbow joint is a possible complication after double-plate osteosynthesis with a 90° configuration, especially after olecranon osteotomy.

Objectives

The goal of this study was to analyze the positioning of the posterolateral humeral plate in order to define guidance values for intraoperative application.

Methods

The positioning of the posterolateral humeral plate in relation to the olecranon in full extension of the elbow joint was analyzed in 71 dissected upper extremities of cadavers. Values on the cadavers were measured under image-intensifier control (distal olecranon impingement line) that can be reproduced intraoperatively.

Results

The average distance between the distal edge of the plate and junction of cartilage and bone at the capitulum humeri was 4.8 mm (SD?±?1.2 mm). The average distances from the medial border of the plate to the lateral border of the olecranon fossa and to the lateral epicondyle were 2.5 mm (SD?±?0.9 mm) and 22.7 mm (SD?±?2.4 mm), respectively. The distal olecranon impingement line averaged 5.2 mm (SD?±?1.5 mm) on the left and 7.2 mm (SD?±?1.4 mm) on the right side of cadavers.

Conclusions

The measured values offer landmarks for correct positioning of the posterolateral humeral plate. The distance between the lateral border of the olecranon fossa and the medial edge of the posterolateral plate as well as the proximal end of the distal olecranon impingement line should be respected in order to avoid impingement. If possible, the posterolateral plate should be placed at least 4.3 mm lateral to the radial edge of the olecranon fossa so that impingement can be successfully avoided.     

A rat model for chronic spinal nerve root compression

Objectives

The pathophysiology of radiculopathy associated with lumbar spinal stenosis and lumbar disc herniation is incompletely understood. The goal of the present study was to establish a chronic spinal nerve root compression model that can mimic lumbar disc herniation or spinal stenosis using silicone tube compression. We also try to link the pathology changes of damaged nerve root with the reaction of microglia in spinal cord in same rat at different time points.

Methods

Thirty rats were used in this study. The L5 nerve roots (dorsal and ventral) were exposed by hemilaminectomy; the diameter of the L5 nerve root was measured at the 2 mm proximal from the dorsal root ganglia. The dorsal and ventral nerve roots of L5 were compressed using a silicone tube, and the sham group was only exposed dorsal and ventral roots of L5. Five rats from the sham group were perfused at 8 days after surgery, and 25 rats from the model groups were perfused at 3, 8, 12, 45 days, and 5 months after surgery, each model group was composed of 5 rats according to the time point. The L5 spinal cord segments and nerve root that compressed by silicone tube were harvested from the same rat. Microglia and neuron in the spinal cord were stained by immunohistochemistry, and the nerve root was shown by electron microscope.

Results

In sham-operated rat, the arrangement of axon and myelin sheath is normal, the ventral root is mainly composed of large axon (>6 μm) and it is composed of 46.3 % of all the axons of the ventral root; the average myelin thickness of large axon is 1.86 μm; the dorsal root is mainly composed of medium (2–3.9 or 4–5.9 μm) axons and they are composed of 79.1 % of all the axons of the dorsal root; the average myelin thickness of this category is 0.94 or 1.55 μm. The average myelin thickness of large axon in ventral root reduced to 0.97 and 1.19 μm from more than 1.86 μm after compression for 3 and 8 days separately. Most of myelin sheath disappeared after 12 days of compression; the myelin sheath was partly restored at 45 days after compression which the myelin sheath thickness of large axons in ventral root was 0.47 μm. The medium category in dorsal root reduced to 0.59 or 0.72 μm from 0.94 μm, and 1.55 μm after compression for 3 days (p < 0.05 to p < 0.0001). The medium category axon in dorsal root is also 0.47 μm after compression for 45 days (p ≤ 0.0001). The myelin sheath was almost totally restored at the 5 months of compression; the myelin sheath thickness returned to normal and the axons were intact in structure under EM. The number of Iba1-positive microglia increased by 18.69, 40.44, and 18.49 % after compression for 3, 8, and 12 days separately in the ipsilateral dorsal horn and 21.26, 32.15, 22.87 % in ventral horns, and the activation of microglia was also prominent in contralateral sides of the dorsal and ventral horn at 8 days time point. The microglia cell reconverted to resting status after compression for 45 days or 5 months.

Conclusion

The chronic spinal nerve root compression with silicone tube produces a recoverable damage to nerve root, which produces recoverable microglial activation in the spinal cord. These results demonstrated that the chronic spinal nerve root compression with silicone tube could mimic the pathological changes of lumbar spinal stenosis or lumbar disc herniation.     

Stretching of roots contributes to the pathophysiology of radiculopathies

Purpose

To perform a synthesis of articles addressing the role of stretching on roots in the pathophysiology of radiculopathy.

Cervical neural space narrowing during simulated rear crashes with anti-whiplash systems

Purpose  

Chronic radicular symptoms have been documented in whiplash patients, potentially caused by cervical neural tissue compression during an automobile rear crash. Our goals were to determine neural space narrowing of the lower cervical spine during simulated rear crashes with whiplash protection system (WHIPS) and active head restraint (AHR) and to compare these data to those obtained with no head restraint (NHR). We extrapolated our results to determine the potential for cord, ganglion, and nerve root compression.     

Primärstabilität des Kapsel-Labrum-Komplexes nach Rekonstruktion mit Mitek-Bioknotless-Fadenankern am humanen Schulterkadavermodell

Background

This study examines the postoperative stability of the Mitek Bioknotless anchor system with biomechanical draw-out pulling in human cadaver shoulders.

Method

With simulation of anterior shoulder dislocation a test group (n=10, Ø 45 years) was tested against a native group (n=8, Ø 47 years). All shoulders were dissected up to the passive stabilizers. In the test group an artificial Bankart lesion was created and repaired with three Mitek Bioknotless anchors. The humeri of both groups were fixed in 60° glenohumeral abduction and 90° external rotation and then dislocated in a ventral direction. For evaluation purposes the ultimate draw-out strength, mode of failure, translation of humeral head, capsular slope, and bone density in the test group were measured.

Results

In the test group the ultimate strength was a median of 937 N (min. 554 N, max. 1,294 N) with 28 bony anchor dislocations, 1 suture rupture, and 1 capsular rupture, and in the native group with 6 Bankart and 2 HAGL lesions it was 1,214 N (708 N, 1,471 N). The bone density showed a positive correlation to the draw-out strength regarding cortical density and total density.

Conclusion

Regarding the high draw-out strength the Mitek Bioknotless anchor system provides enough stability for early functional treatment.     

Ulnar nerve morbidity as a long-term complication of pediatric supracondylar humeral fracture

Background

Supracondylar humeral fractures are common in children. We studied long-term ulnar nerve symptoms secondary to these fractures and analyzed the treatment for ulnar neuropathy.

Materials and methods

The cohort included 91 patients with a supracondylar humeral fracture in childhood, on average 12 years previously, in the geographic catchment area. All the cases were reexamined in regard to ulnar nerve morbidity. Cases with secondary ulnar neuropathy were treated nonoperatively and operatively.

Results

Ulnar neuropathy was present in four cases (4.4 %). They all had suffered from a dislocated fracture, and they had been operated primarily. Another three patients had slight ulnar nerve symptoms. Hence, the total prevalence of secondary ulnar nerve morbidity was 7.7 %. A jumping nerve was seen in 9.9 %; 51.6 % had a diminished axial angle.

Conclusions

We report a defined pattern of long-term ulnar nerve morbidity after pediatric supracondylar humeral fracture. The prevalence of neuropathy is alarming in the young population (<25 years of age).     

Transcranial segment of the trigeminal nerve: macro-/microscopic anatomical study using sheet plastination

Background

Trigeminal neuralgia (TN) may be caused by the mechanical compression of the trigeminal nerve. In the studies on the location of mechanical irritation and entrapment of the nerve, attention has been paid mostly to vascular structures in the subarachnoid space. Few studies have explored the relationship between the trigeminal nerve and its surrounding structures along its course in the skull base. The aim of this study was to examine and trace the root, ganglion and three divisions of the trigeminal nerve and their relationships with surrounding soft and bony structures in the skull base, and to identify the likely mechanical compression points.

Methods

A total of 26 adult cadavers (ten females, 16 males; age range, 45–81 years) were examined in this study, eight for dissection and 16 for sheet plastination study.

Results

Anatomical structures that may make the trigeminal nerve susceptible to entrapment in the skull base were located at (1) the inferolateral edge of the mouth of Meckel’s cave, (2) the middle cranial fossa dura and the lateral wall of the anterior intracavernous portion of the internal carotid artery, (3) the ridge of the medial wall of the foramen rotundum, and (4) the twisted periosteum and venous plexus of the foramen ovale.

Conclusion

This study identified four likely mechanical compression points along the course of the trigeminal nerve in the skull base. Knowledge of these TN-susceptible sites may be useful to both skull base surgeon and TN-animal model researcher, particularly when they study TN without vascular compression.     

Proximal humeral fractures: an understanding of the ideal plate positioning

Purpose

The present study aims to evaluate if the bicipital groove can be used as a parameter for ideal plate positioning in proximal humeral fixation applying locking compression plate.

Method

The authors questioned whether the bicipital groove can be used as a parameter for ideal plate positioning applying locking compression plate for proximal humeral fractures. A method using the bicipital groove as the main parameter was developed using computed tomography scan (CT-scan). Seventy shoulders presenting fracture absence were used to calculate proper plate positioning, allowing the largest area for locked screw placement into the humeral head. Intraclass correlation coefficient and Bland and Altman graphics calculated intra-observer reliability for CT-scan evaluation.

Results

All observers presented satisfactory plate positioning using this method. The mean differences for observers were close to zero, suggesting high interobserver reproducibility. A significant (p?<0.0001) intra-observer agreement existed for the three evaluators. Observer 2 agreement was the strongest (ICC?=?0.98), showing almost perfect reproducibility measurement, followed by observer 3 (ICC?=?0.84) with good reproducibility, and lastly observer 1 demonstrated moderate degree agreement (ICC?=?0.47).

Conclusion

Considering the CT-scan analysis, the bicipital groove can be used as a parameter for ideal plate positioning in proximal humeral fractures. This method demonstrated satisfactory intra-observer reproducibility. Adopting this method, longer and better distributed screw placement provides more stable fixation for proximal humeral fractures.     

Spinal to accessory nerve transfer in traumatic brachial plexus palsy: is body mass index a predictor of outcome?

Introduction

Several factors that affect functional recovery after surgery in severe brachial plexus lesions have been identified, i.e., time to surgery and presence of root avulsions. The body mass index (BMI) of the patient could be one of these possible factors. The objective of the present paper is to systematically study the relationship between BMI and the outcome of abduction following spinal accessory to suprascapular nerve transfer.

Methods

We retrospectively studied 18 cases that followed these inclusion criteria: (1) Male patients with a spinal accessory to suprascapular nerve transfer as the only procedure for shoulder function reanimation; (2) at least C5-C6 root avulsion; (3) interval between trauma and surgery less than 12 months; (4) follow-up was at least 2 years; (5) no concomitant injury of the shoulder girdle. Pearson correlation analysis and linear regression was performed for BMI versus shoulder abduction.

Results

The mean range of post-operative abduction obtained across the entire series was 49.7° (SD ± 30.2). Statistical evaluation revealed a significant, negative moderately strong correlation between BMI and post-operative range of shoulder abduction (r?=??0.48, p?=?0.04). Upon simple linear regression, time to surgery (p?=?0.04) was the only statistically significant predictor of abduction range negatively correlated.

Conclusions

Analysis of this series suggests that a high BMI of patients undergoing brachial plexus surgery is a negative predictor of outcome, albeit less important than others like time from trauma to surgery. Nevertheless, the BMI of patients should be taken into consideration when planning surgical strategies for reconstruction.     

Long-term surgical outcomes of cervical dumbbell neurinomas

Study design

Retrospective case series.

Objective

To evaluate our treatment strategy for cervical dumbbell neurinoma.

Summary of background data

In treating cervical dumbbell neurinoma, possible difficulties include reoperation due to recurrent tumor, denervation due to nerve root resection, and postoperative spinal deformity due to extensive bony removal.

Methods

We reviewed 75 cases of cervical dumbbell neurinoma that were treated surgically between 1985 and 2006. Postoperative neurological deficits, effects of surgical margins on tumor recurrence, and surgical complications were investigated retrospectively.

Results

Sensory and motor deficits due to resection of specific nerve roots appeared temporarily in 33 and 23 % of all cases, and persisted in 8 and 8 % at final evaluation, respectively. Total, subtotal, and partial resection was performed in 57, 13, and 5 cases, respectively. The total resection rate was low in the tumors that had large extraforaminal components. Of the subtotally resected 13 cases, only two cases of high tumor-growth rate required re-operation or showed tumor growth. Among the five partially resected cases, re-operation was necessary in two cases 13 and 15 years later because of aggravated neurological symptoms due to tumor growth. Two patients who underwent C2 laminectomy developed kyphosis, and three patients who underwent facet joint resection and curettage of vertebral body lesions developed scoliosis.

Conclusion

Total resection should be attempted for cervical dumbbell tumors. In cases where total resection was potentially of high risk, however, subtotal resection (within the capsule) was found to be a practical choice yielding favorable long-term outcome when the tumor growth rate (MIB-1 index) was low.     

Shoulder hemiarthroplasty for complex humeral fractures: a 5 to 10-year follow-up retrospective study

Purpose

The purpose of this study is to review our experience with proximal humeral locking plates, including complications, functional outcomes, strength recovery and predictors of successful treatment.

Methods

Seventy unstable proximal humeral fractures were treated with open reduction internal fixation (ORIF) with the use of locking proximal humerus plate. At an average follow-up of 31 months, the clinical and subjective outcomes were evaluated, and complication was analysed.

Results

The average Constant score was 72. The mean disabilities of the arm, shoulder and hand score was 23. The average range of motion was as follows: mean range of anterior elevation and abduction 120°–150°; external rotation in abduction 64° and in adduction 44°; and internal rotation T12.

Conclusion

On the basis of the overall functional and clinical outcome obtained, it is possible to suggest that the ORIF of the proximal humerus fractures using locking plate represents a helpful option that can lead to a good clinical and functional outcome even in the most complex fractures. Level of evidence, Case Series, Treatment Study, Level IV.     

The amount of humeral head impaction of proximal humeral fractures fixed with the Humerusblock device

Purpose

The Humerusblock is a minimally invasive device allowing fixation of proximal humeral fractures. A drawback of the device is possible K-wire perforation of the head with the need for early removal of the implant. We assessed the amount of humeral head impaction and its role in the postoperative varus/valgus deviation of the humeral head in fractures of the upper humerus treated with Humerusblock.

Methods

Fractures were classified according to the Codman-Lego system. The length of the posteromedial metaphyseal extension and integrity of medial hinge were measured; metaphyseal comminution was assessed. Accuracy of fracture reduction was classified as excellent to poor. An original method of measurement of amount of postoperative impaction of the humeral head was developed. The impaction and varus/valgus inclination of the heads were measured comparing postoperative and three-month follow-up radiographs. Constant score and its relation to sintering was calculated at 12-month follow-up.

Results

Forty-three fractures were available for follow-up. The amount of humeral head impaction was 3.9 mm on average and was directly correlated with patient’s age, sex, Codman-Lego classification, varus inclination and mataphyseal comminution. The postoperative cervico-diaphyseal angle was restored in 35 cases, with 81 % good results. The Humerusblock was removed in 41 % of cases because of K-wire perforation of the humeral head. A negative correlation was found between impaction and Constant score.

Conclusions

The amount of humeral head impaction is related to patients’ age, sex, and fracture patterns, being the most prone to compaction those with metaphyseal comminution. Humeral head impaction negatively affects final Constant score.     

Die additive Zuggurtung der Rotatorenmanschette bei der winkelstabilen Plattenosteosynthese am proximalen Humerus

Objective

Can additive fiber cerclage (FC) reduce secondary displacement in unstable 3-part proximal humeral fractures stabilized by angle-stable plates? Is there any effect of different head screw configurations?

Methode

An unstable 3-part fracture model of the humeral head was developed by preserving the rotator cuff in 24 paired, osteoporotic shoulder specimens. 6 pairs were stabilized by PHILOS® plates, and 6 others by HSP®. Each left shoulder received FC. 4 groups arose (n=6): I) HSP® with FC, II) HSP without FC, III) PHILOS® plate with FC, and IV) PHILOS plate without FC. 4 physiological load cases were simulated by a robot-assisted shoulder simulator. Using real-time analysis, interfragmentary motion was measured.

Results

Matched-pair analysis of the groups with FC vs. those without FC showed no significant differences in motion at gap I (greater tuberosity head) or II (subcapital) in any load case, apart from interior rotation in groups III and IV at gap II; in these, motion was greater without FC. No differences were seen with different head screw configurations in any load cases.

Conclusions

In cases of anatomical reduction and optimally placed implants, FC did not show an additional stabilizing effect in the unstable 3-part fracture model. Different head screw configurations did not influence stability.