The ‘Floating Humeral Head’, A Case Series of Combined Proximal Humeral and Glenoid Fracture Dislocations

Joshua CY Ong*, Mahmoud A Awadallah, Andrew J White, Paul M Robinson

Trauma & Orthopaedic Department, Peterborough City Hospital, Bretton Gate, UK


Background: Fracture of the proximal humerus combined with dislocation of the glenohumeral joint and a soft tissue or bony Bankart lesion are rare. Management options are largely surgical and different approaches to fixation have been described. The reported outcomes are generally poor.

Methods: We present a series of three rare cases of traumatic dislocations of the shoulder associated with combined fractures of the proximal humerus and glenoid that were treated with surgical fixation. We describe the surgical technique and clinical outcomes.

Results: Our patients had multiple medical comorbidities; and coupled with the burden of injury, made a slow post-operative recovery (mean Constant-Murley score of 48 points over a mean follow-up time of 20 months).

Conclusion: A high index of suspicion and appropriate imaging is required to properly diagnose and surgically manage this uncommon pattern of injury. We recommend surgical treatment of these severe injuries, to stabilise the glenohumeral joint, and to achieve optimal clinical outcomes.


The shoulder is the most commonly dislocated large joint. Its dislocation occurs in 1–2% of the population17. Anterior shoulder dislocation accounts for 90–95% of all shoulder dislocationsAG1. The most common bony injuries associated with isolated anterior shoulder dislocation are Hill-Sachs lesions and corresponding bony Bankart lesions, followed by rotator cuff tears3.

Depending upon the mechanism and severity of injury, a range of other fractures i.e. greater tuberosity fracture, humeral shaft fracture, coracoid fracture, humeral neck fracture, and avulsion fractures of anterior glenoid rim are possible30. Greater tuberosity fractures have been noted in 10-30% of shoulder dislocations11. Similarly, Bahrs et al. found that over 50% of greater tuberosity fractures were associated with traumatic anterior glenohumeral dislocation in a review of over 100 patients4.

Sherif et al. reported on 9 patients that had concomitant anterior dislocations of the glenohumeral joint and fractures of the neck of humerus27, without any bony injury to the glenoid. Fracture dislocations of the shoulder can be associated with soft tissue or bony Bankart lesions, but it is a rare occurence24. Robinson et al. found 3 bony Bankart injuries in their group of 58 consecutive fracture dislocations of the proximal humerus24. Surgical fixation of these injuries was only for the humerus and not the glenoid.

Avulsion fractures (the so-called chip fractures32) of the anterior inferior glenoid rim occur by a mechanism of shoulder abduction and external rotation at the time of dislocation3,30. Large glenoid fractures can cause shoulder instability, that increases if the fracture involves one-fifth or more of the anterior part of the glenoid cavity or if the size of fragment is greater than half of the largest diameter of the glenoid2.

Combinations of these injuries are rare, and we present three patients with this pattern of injury as contribution to the literature.

Three patients, age range 50 to 68 years old, presented consecutively to our hospital with this pattern of injury between 2015 to 2017.

Initial management entailed standard assessment, resuscitation and stabilisation of systemic problems according to advanced trauma life support (ATLS) principles. During the secondary survey, the neurovascular status of the affected limb was assessed, and the fracture dislocation was confirmed by radiographs. Confirmation of a fracture dislocation of the shoulder lead to an urgent Computer Tomography (CT) scan (Figure 1A-C) and preparation for surgical management on the next available shoulder operating list. 3D reconstructions in the axial, coronal and sagittal planes and volume rendered 3D reconstructions allowed assessment of the direction of dislocation, tuberosity displacement, and glenoid fracture size5. Closed reduction with sedation in the emergency department was not possible for due to the complete joint dislocation associated with fracture, and treatment proceeded straight to open reduction and internal fixation on the next available emergency list the next day (less than 24 hours).

JOOS-21-1122-Fig1

Figure 1A: (Patient A pre-operative 3dimensional CT reconstructions)

Figure 1B: (Patient B pre-operative 3dimensional CT reconstructions)

Figure 1C: (Patient C pre-operative 3dimensional CT reconstructions)

The patients were relatively young but had poor American Society of Anaesthesiologists (ASA) scores of 2-3. All three patients had significant comorbidities. They all sustained low energy injuries by a fall from standing height, with an isolated injury to their dominant side. Medical co-morbidities are listed in table 1.1.

Table 1.1: Demographics and treatment pathway

Demographics

Patient A

Patient B

Patient C

Gender

Female

Female

Male

Age

67

68

50

Hand Dominance

Left

Right

Right

ASA

2

3

3

Comorbidities

Vasculitis, Scleroderma

Diabetes, CVA

Diabetes, Asthma

Fracture of Humerus (Neer)

3 part

3 part

4 part

Bankart Lesion type

Bony

Bony

Bony

Glenoid fracture displacement (mm)

13.5

16

13

Surgical Approach

Deltopectoral

Deltopectoral

Deltopectoral

Humeral Fixation

Fixed angle device & Rotator cuff repair

Fixed angle device & Synthetic bone graft

Fixed angle device

Glenoid Fixation

Cannulated screws

Glenoid anchors

Cannulated screws

Complications

Frozen Shoulder

None

Axillary nerve neuropraxia

Range of Movement Elevation

90

90

80

Range of Movement ER

10

20

10

Range of Movement IR

SIJ

SIJ

SIJ

Constant Scores (18 months)

41

35

68

All patients underwent a general anaesthetic augmented with interscalene regional nerve block. Patients were positioned in beach chair with the operated arm free. Intraoperative fluoroscopic screening was utilised throughout. Surgical exposure was achieved via the delto-pectoral approach. Post operatively the patients continued as inpatients for observations and analgesia and were discharged when safe and medically fit. Table 1.1 lists the patient demographics, injury pattern, treatments, and outcomes.

Standard post-operative precautions were prescribed with a sling for six weeks, early elbow and wrist movement within the ‘inner cone’ only (i.e., restricted external rotation). Wound reviews at 10-14 days with radiographs at that time. Further routine follow-up and clinical assessments of pain, range of movement, function and radiological union were at three, six, twelve and eighteen months (Figure 2A-C).

JOOS-21-1122-Fig2

Figure 2A: (Patient A radiographs at 6 months follow-up)

Figure 2B: (Patient B radiographs at 6 months follow-up)

Figure 2C: (Patient C radiographs at 6 months follow-up)

Patient A sustained a two part proximal humerus fracture with significant extension into the calcar region, and initially had fixation of the proximal humerus only with a Peri-Loc 3.5mm 5 Hole proximal humerus locking plate (Smith & Nephew, Memphis, TN). Intraoperative assessment of the rotator cuff revealed a full-thickness tear of both the supraspinatus and infraspinatus tendons. This was repaired at the same time with Fibrewire sutures (Arthrex, Naples, FL, USA) to the locking plate and one Corkscrew FTII suture anchor (Arthrex, Naples, FL, USA).The stability of the glenoid fracture was assessed intra-operatively and decision was to treat this conservatively, as the joint dislocation was attributed to the significant cuff tear. After 4 weeks, Patient A was discovered to have x-ray evidence of a anterior- inferior subluxation of the glenohumeral joint, and required a secondary procedure which involved reconstruction of the glenoid with an Eden Hybinette procedure using pelvic autograft. The glenoid was approached through a subscapularis splint in the mid portion, followed by a medial ‘T’ capsulotomy. Intra-operatively the glenoid fracture was noted to be 25-30% of the anterior-posterior diameter. The graft was fixed with a 2 hole wedged profile plate (Arthrex, Naples, FL, USA) and two 3.75mm cannulated compression screws. The capsulotomy was repaired with a Lupine BR anchor and Orthocord (DePuy Mitek, Norwood, MA).

Constant-Murley scores6 of Patient A continued to slowly improve throughout follow-up (from 18 points at 6 months post surgery) but plateaued midway (41 points at 30 months post surgery ). CT of the shoulder performed 36 months after the injury confirmed union of the glenoid bone graft, but signs of glenohumeral joint osteoarthritis.

Patient B sustained a three part proximal humerus fracture, which included a greater tuberosity fragment. Surgical management proceeded with fixation of the proximal humerus first, which provided a stable lever arm to approach the small glenoid bony Bankart through a subscapularis split. The glenoid fracture was noted too small for implant fixation, and was stabilised with two Orthocord suture loops (DePuy Mitek, Norwood, MA) around the fracture fragment and capsular-labral complex, reduced to peripheral Lupine BR anchor (DePuy Mitek, Norwood, MA) on the glenoid base29.

On followup the patient experienced a meagre clinical improvement (from 15 points at 6 months post surgery) and plateaued in pain and function very early (35 points at 18 months post surgery).

Patient C had sustained a locked anterior fracture dislocation of the humeral head. Open reduction of the glenohumeral joint (GHJ) was difficult to achieve due to the discontinuity of the humeral head and shaft. The GHJ was reduced with traction sutures in the rotator cuff and by using a lever that was applied through the rotator interval. After GHJ reduction the humeral head was noted to be unstable and discovered to have tenuous glenohumeral capsular attachments that had avulsed off the unfractured part of the glenoid. The floating humeral head was too unstable for adequate proximal humeral fracture reduction, and therefore the GHJ was temporarily transfixed with a 1.6mm K-wire to aid stable reduction and plate fixation of the proximal humerus. Fixation was achieved with the Aptus 3.5mm Proximal Humerus Plate (Medartis, Basel, Switzerland). The glenoid was then approached via a transverse muscle split in the subscapularis and a ‘T’ capsulotomy. The glenoid fracture was reduced and fixed with two 3.5mm cannulated screws. The capsulotomy was repaired with Vicryl (Ethicon, UK) sutures.

Patient C was noted to have a post-operative axillary nerve and suprascapular nerve palsy that was not evident at the time of injury. Nerve conduction studies suggested a ‘double crush’ phenomenon from neurapraxia and a pre-existing severe C5/C6 cervical neck radiculopathy. There was a steady recovery to pre-injury levels of muscle power and sensation after six months. Patient C had significant early functional gains (40 points at 6 months post surgery) and a more gradual increase as the year progressed (68 points at 12 months post surgery). The mean Constant-Murley score for all three patients was 48 points.

The ‘floating shoulder’ was described by Ganz and Noesberger in 1975, and further defined by Goss et al. as a double disruption of the superior shoulder suspensory complex8,10.

Biomechanical concepts include structural integrity of the clavicle- acromioclavicular joint, scapular body junction and the clavicular-coracoclavicular ligaments-coracoid linkage. The anatomy of the shoulder becomes unstable, and may lead to problems with healing and function, and sometimes degenerative joint disease22. Hardegger et al. and Butters et al. recommended surgery in these cases, and other authors suggest initially fixing clavicle fractures before proceeding to the next component of the injury, if the complex remains unstable13,14,19,20. The ‘triple dislocation fracture’ was described in two articles31,22. This injury pattern involves anterior shoulder dislocation with concomitant fracture of the glenoid rim, greater tuberosity, and coracoid process23. Other concomitant injuries of the upper limb have been described. The ‘floating arm’ was described by Guven et al. and consist of a ipsilateral bony humerus fracture of both the proximal and distal ends12,33,34,35. The ‘floating elbow’ involves fractures of both humerus and ipsilateral forearm, with an unstable elbow joint28. The ‘floating forearm’ was also described in a case report of an elbow dislocation with ipsilateral distal radius and ulnar fractures, and the paediatric patient requiring operative management. We believe that our patient cohort fit into this category of unstable simultaneous fractures, and can be considered a ‘floating humeral head’.

The patient cohort at risk of these injuries (shoulder dislocations associated with isolated fractures of the humeral head, neck, tuberosity, or injury to the glenoid) is older than 40 years of age, first episode of dislocation, and high energy mechanism7. Emond et al. formulated a predictive model for these injuries; however there were almost a quarter of these patients that did not have pre-reduction radiographs due to young age, female gender and similar injuries in the past7. Rowe et al. also showed a five-fold increase in the probability of clinically important fracture associated with shoulder dislocation in patients aged 40 years or older26.

We noted our three patients sustained low energy trauma due to falls from standing height, which were not part of their predictive model. This factor does reflect that low energy injury may be a surrogate for frailty, and also acts as an independent predictor in associated neurological injury demonstrated by Robinson et al. All our patients had multiple systemic comorbidities such as diabetes, and one of our patients did have a transient axillary nerve palsy, complicated by the presence of diabetic neuropathy25.

Königshausen et al. classified glenohumeral combination fractures into groups according to the severity of each fracture, and suggested a treatment algorithm for these injuries, predominantly surgical treatment18. Our cohort of patients would correspond to their classification of Type 2 glenohumeral combination fractures, describing them as large anterior glenoid rim fracture and proximal humeral fracture.

There has only been one case report describing the detailed surgical management in a case of a fracture dislocation of the proximal humerus that was combined with a glenoid fracture16. The authors describe radiological union but did not include clinical and functional results. In all our cases surgery was the management of choice due to the instability caused by both the glenoid injury and loss of integrity in the lever arm of the humerus. It was felt that non-operative management would lead to poorer outcomes due to a combination of proximal humeral mal-union and glenohumeral instability with GHJ incongruity and the potential for degenerative change. In regard to the glenoid injury, our patients were classified as Ideberg Type 1A15 (Mayo modification21). The significant displacement (more than 4mm articular step off and gap) influenced the decision for surgical fixation. Furthermore, our patients did have expectations to return to high level of independence and function.

The surgical approach was by the anterior approach to the shoulder via the delto-pectoral interval for both the humeral and glenoid fixation. The sequence of fixation for this injury triad has never been described in the literature, and we propose starting with the proximal humerus fracture first, followed by the glenoid fracture. If the floating humeral head cannot be controlled with rotator cuff sutures, it can be transfixed temporarily with a Kirschner wire. The glenohumeral joint was exposed by splitting the subscapularis muscle in the plane of the muscle fibres. We found that a single delto-pectoral approach was adequate for fixed angle plate osteosynthesis of the humerus, with sutures in the tendinous cuff allowing the implant to parachute down to the humeral head, aiding reduction.

We noted the early functional outcomes are poor for our patients, which are significantly lower compared to patients that experience proximal humeral fracture fixation alone31. These were a combination of capsular stiffness and global muscle weakness, and physiotherapy did not lead to significant functional gains, despite radiographic evidence of full bony union.

Higher rates of complications (fracture displacement, joint instability, heterotopic ossification, avascular necrosis, and implant loosening) are not uncommon to these combination fractures treated by surgical fixation rather than arthroplasty (e.g., Hemiarthroplasty or reverse shoulder replacement).

One of our patients (Patient A) with a glenoid fracture that was initially treated non-operatively, presented with early post-operative instability, and required subsequent fixation of the glenoid fracture. In retrospect a combined fixation of the proximal humerus fracture and glenoid fracture would have prevented late subluxation. Another option would be to undergo a reverse shoulder arthroplasty, providing there was sufficient bone stock for the glenoid component. Garofalo et al. reported good to excellent results in 26 patients treated with reverse shoulder arthroplasty, with the aid of a contoured glenoid bone graft during implantation9.

Revision surgery due to loss of fixation is common, and occurred in two of the six patients reported by Plachel et al.22, and does indicate the complexities of these injuries. This cohort of patients did have good Constant-Murley scores (mean 72), and reported being ‘very satisfied’ with their outcome, in contrast to our patients with very modest scores (mean 48).

The retrospective design of our study and the small case series with variable fracture patterns are limiting factors.

‘Floating humeral head’ injuries of the upper limb pose a significant surgical challenge to treat. Despite the rare occurrence, the clinician should first have awareness of the combination of these pathologies and the possible treatment options. Patients should be investigated with CT to detect glenoid fractures and quantify the articular component. From our experience we recommend combined early surgical management of both the proximal humerus and glenoid fractures utilising the delto-pectoral approach, without the need for a coracoid osteotomy. Fixed angle devices provide stable fixation of the proximal humerus, which should be approached first, facilitating glenohumeral joint reduction and glenoid exposure. This approach also allows rotator cuff sutures to facilitate reduction of displaced tuberosity fractures. Glenoid fractures may have better fixation with implants that produce fracture compression and rigid stability rather than anchors, and this may help to avoid late displacement. For irreducible fractures a reverse geometry shoulder arthroplasty should be considered. Patients have a guarded prognosis for long term outcomes, post- operative stiffness being more common than persistent instability, and patient expectations must be managed appropriately. Further research to evaluate the long term incidences of post traumatic arthritis, instability and avascular necrosis is required to further prognosticate the treatment of these rare injuries.

No outside funding or grants were received that assisted in this study.

There are no conflicts of interest for the any authors, their immediate families, and any research foundation with which they are affiliated, including receiving royalties, stock or stock options, consultant agreements, or ownership from or with any commercial entity related to the subject of this work.

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Article Info

  • Journal of Orthopedics and Orthopedic Surgery
  • Article Type : Original Article
  • View/Download pdf
  • DOI :

Article Notes

  • Published on: December 24, 2020

Keywords

  • Fracture

  • Proximal humerus
  • Glenoid fracture
  • Fracture dislocation
  • Shoulder
  • Open reduction internal fixation
  • Floating joint

*Correspondence:

*Dr. Joshua CY Ong
Trauma & Orthopaedic Department, Peterborough City Hospital, Bretton Gate, UK
Email: joshua.ong@nhs.net.

©2020 Ong JCY. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License.