The use of locking plates in proximal humeral fractures: comparison of outcome by patient age and fracture pattern

Michael Leonard, Leibo Mokotedi, Uthman Alao, Aaron Glynn, Mark Dolan, Pat Fleming.

Department of Trauma and Orthopaedic Surgery,Cork University Hospital, Cork, Ireland

Address for Correspondence:
Michael Leonard
Department of Trauma and Orthopaedic Surgery, Cork University Hospital, Wilton, Cork, Ireland.
Phone:  (00353)879163747
E-mail: mikeleonard77@gmail.com

Abstract:

This study was undertaken to evaluate the efficacy of a proximal humeral locking plate, and to specifically study the effect of patient age and fracture type on outcome.

Thirty-one cases of proximal humeral fractures fixed using the proximal humeral interlocking (PHILOS) plate were reviewed.

Average functional scores ( minimum 18 months post-op) per AO/ASIF fracture type were 25.3 for type A, 21.4 for type B and 22.7 for type C. There was no statistically significant difference between groups. Functional score for patients over 65 years of age were significantly inferior (p=0.03).

 At final radiologic review (mean 12 months post-op) 30 (96%) of the patients had united. Seven patients (22.5%) required a second surgical procedure.

We obtained both good functional results and bone healing with the PHILOS plate irrespective of fracture type, older patients had a poorer outcome. We caution surgeons on the high potential for re-operations with its use.

J.Orthopaedics 2009;6(3)e2

Keywords:

Proximal humeral fractures; Locking plates; PHILOS

Introduction:

Proximal humeral fractures are common, accounting for 5 to 9% of all fractures ¹. In patients over 65 years of age they are the third most common fracture after fractures of the hip and distal radius ². Most proximal humeral fractures are stable, minimally displaced and can be managed conservatively ³.

The surgical treatment of displaced unstable fractures however remains a challenge. Non-operative management of these more severe fractures is associated with poor results ³. The large range of operative techniques described (e.g., K wiring, tension band wiring, plating, nailing, arthroplasty) for managing the more complex fractures is a testament to the lack of clear superiority of any one method. Most of these techniques have been associated with complications related to hardware failure, osteonecrosis, non-union, malunion, rotator cuff impairment, and impingement ⁴.

Proximal humeral locking plates such as the proximal humeral interlocking (PHILOS) plate (Synthes, Switzerland) offer several potential advantages in the treatment of these injuries. They are site specific, low profile plates. The plate is precontoured for the proximal humerus and the insertion of locking screws obviates the need of plate to bone compression, preserving the bones blood supply. The insertion of multiple polyaxial locking screws through the specific targeting device into the humeral head fragment provides fixed-angle support in multiple planes which should in theory maintain the reduction achieved ¹, while allowing for early mobilisation. However, in spite of all the potential benefits significant levels of construct failure and revision surgery with  the use of proximal humeral locking plates have been reported, particularly in patients over 65 years of age ⁵.

This study was undertaken to evaluate the use of the PHILOS plate system for the treatment of proximal humeral fractures. We specifically wanted to examine the effectiveness of the PHILOS plate on different fracture patterns, the impact of patient age, and of the humeral neck-shaft angle attained following fixation on outcome.

Materials and Methods:

From May 2003 to May 2007 31 patients with displaced fractures of the proximal humerus had open reduction and internal fixation with a PHILOS plate (Synthes, Switzerland). Patients were identified from the trauma database of a single university based level 1 trauma centre.

There were 23 women and 9 men with a mean age of 61.6 years (19 to 86). Twenty- five of the patients sustained their injury following a fall, 5 from a road traffic accident and 1 from direct assault.

Fractures were classified with the AO/ASIF system (8), there were 8 type A (extra-articular unifocal), 15 type B (extra-articular bifocal) and 8 type C (articular) fractures. All fractures met the indications for operative treatment outlined by Neer et al ⁷, i.e. an angulation of the articular surface of more than 45 degrees’ or  displacement between the major fracture fragments of more than 1cm.  It is our policy to treat some fracture-dislocations (particularly in the physiologically elderly), head-splitting fractures, and impression fractures that involve over 40% of the articular surface with a hemiarthroplasty.

Operative Technique:
All cases were performed by a senior orthopaedic surgeon. Patients received prophylactic intravenous antibiotics. All patients were placed in the beach-chair position and the C-arm was positioned parallel to the patient at the head of the bed. Satisfactory imaging was ensured before prepping the patient. A delto-pectoral approach was used with minimal soft tissue dissection. The biceps tendon was identified and retracted, and the fracture exposed. On occasion the biceps tendon was found to be interposed in the fracture fragments requiring mobilisation. Traction sutures were then placed around the tendon-bone interfaces of the rotator cuff and tuberosity fragments.  The head fragment, when involved, was then reduced from its typical varus position through manipulation and flexing of the arm. Once in position the traction sutures were used to bring the fragments beneath the head to buttress the articular fragment. The facture was then held temporarily with K wires and the reduction checked fluoroscopically. The traction sutures were then passed through the proximal eyelets on the plate without any tension. The PHILOS plate was then applied lateral to the bicipital groove, 1-2cm distal to the upper end of the greater tuberosity. A conventional non-locking screw was then inserted into the slotted gliding hole on the plate this both brings the plate to the bone and allows for minor adjustments in plate height and position when checked on fluoroscopy. The proximal targeting device was then used to insert the polyaxial locking screws into the head, locking screws were also inserted into the shaft. In one patient with poor bone stock Allomatrix bone substitute (Wright Medical, USA) was used. The traction sutures were then tied down to the plate and final images taken.

The arm was placed in a sling after wound closure. Pendular exercises only were permitted for the first 4 weeks post-operatively, with elbow and wrist range of motion also encouraged. Passive progressing to active range of motion was then commenced under the guidance of a physiotherapist at 4-6 weeks post-op. Resistive strengthening was begun when fracture union was ensured.

 Using the immediate anteroposterior post-operative radiograph the humeral neck-shaft angle was determined. The anatomic neck-shaft angle of the humerus varies from 130 to 140 degrees.

Postoperative outcome was measured with the Quick Disabilities of the Arm, Shoulder, and Hand Outcome Measure (QuickDASH) at a minimum of 18 months postoperatively (range 18-60 months). The QuickDASH is an eleven-item questionnaire that has been validated for either proximal or distal disorders of the upper limb ⁸.The total score ranges from 0 to 100 points, with 100 indicating the most disability. Functional outcome using DASH has been rated as excellent (<20 points), good (20-39 points), fair (40-60 points) or poor > 60 points.

Radiologic outcome measurements recorded at a mean of 12 months (range, 10-15 months) post-operatively included bone-union, defined as the continuity of cortex visible on at least two radiographic views, avascular necrosis, loss of fixation and/or hardware failure.

Statistical Analysis:
Statistical analyses were performed with SPSS 13 (SPSS, Chicago, Illinois). Comparisons were made using Mann-Whitney U tests. A P- value of less than 0.05 was considered to be significant.

Results :

The mean operative time was 81 minutes (range, 60-123) and the mean blood loss was 222 millilitres (range, 150-600). Two patients developed superficial wound infections, both responded to intravenous antibiotics. No neurovascular injuries occurred. Average clinical follow-up period was 14 months (range, 12-18).

Twenty seven patients (87%) responded to the DASH questionnaire. Post-operative Quick DASH scores ranged from 0 to 93.2 (mean = 22.7). The 4 patients who did not respond had undergone an uneventful recovery, had united their fractures radiologically and had been discharged from the clinic.

Average DASH scores per AO/ASIF fracture type were 25.3 for type A, 21.4 for type B and 22.7 for type C. There was no statistically significant difference between these groups.

The mean DASH score for patients under 65 years of age (n=14) was 21.5, and 27.5 for patients over 65 years of age (n=13). The difference was statistically significant (p=0.03).

There was a trend for patients with intra-operative restoration of the humeral head-neck angle to greater than 90 degrees (n=15) to have better outcome (mean DASH score = 20.4) than those who were fixed with an angle of under 90 degrees (n=12, mean DASH score 24.3). However this was not statistically significant.

At final radiologic review (mean 12 months post-op) 30 of the patients had united clinically and radiologically (96%) (Figure 1 a + b). The mean time to union was 12 weeks (9 to 20). 

 Figure 1 a: Pre - operative anteroposterior radiograph of a 54 year old female with a four-part fracture of her left proximal humerus.

Figure 1 b: Note the multiple angled screw fixation and solid bony union evident on the post-operative radiograph at 8 months, with no signs of avascular necrosis.

Seven patients (22.5%) required a second surgical procedure. Three patients failed to unite after initial fixation, one a 19 year old female had autologous bone grafting alone performed (Figure 2 a +b), the other two (both over 65 years of age) underwent plate removal, bone grafting and intramedullary nailing. Both the young female patient and one of the patients over 65yrs of age went on to unite, the other patient did not and subsequently had a hemiarthroplasty performed 7 months after PHILOS plate fixation. Two patients required removal of the plate which in both cases had been placed in an excessively superior position causing symptomatic impingement. One patient required removal of a prominent screw and one patient required a manipulation under anaesthesia for a frozen shoulder following fracture healing.

Figure 2 a: A completely displaced proximal humeral fracture in a 19 year old girl. The fracture was treated with a PHILOS plate but had not united at 4 months post-operativley.

Figure 2 b:Autogenous iliac crest cancellous graft was  subsequently inserted and the fracture united at 6 months post-operativley.

Avascular necrosis (AVN) was observed in 2 patients both of whom had AO/ASIF type C fractures. In both cases only a small percentage of the humeral head was involved, the fracture healed and there was no perforation of the humeral head by any of the screws.

Discussion :

Proximal humeral fractures are challenging to treat. Despite being common injuries there are no clear-cut indications for any of the various surgical options described ⁴. Defining correct treatment guidelines through analysis of current treatment options is becoming increasingly important as the prevalence of osteoporotic fractures of the proximal humerus is expected to rise in the next three decades and the functional outcome achieved after treatment may determine a patient’s level of independence ⁹.

The PHILOS plate was designed to improve screw fixation and minimise soft tissue dissection. It attempts to achieve these aims through a combination of multidirectional locking screws for the head, precontouring of the plate and locking screws in the shaft ¹⁰. The clinical results to date have been mixed ^1,5,10.

This study evaluated the clinical and radiological results of the PHILOS plate used in 31 patients over a 4 year period in a University based Level 1 trauma centre.

We found no significant difference in functional outcome using DASH scoring after PHILOS plate fixation between fracture types using the AO/ASIF classification system at a minimum of 18months post-operatively. We could find only one other paper which compared fracture type before PHILOS fixation with clinical outcome. Bjorkenheim et al., in their study reported a reducing trend in clinical outcome related to severity of fracture at a minimum follow-up of 1 year, but they did not report any statistical analysis of their results. However the 3 cases of non-union and the 2 cases of AVN we report all occurred in the more severe fracture types B and C.

The impact of age on outcome after PHILOS plate fixation is of interest, particularly as there is a general belief that these plates provide more secure fixation in osteoporotic bone ⁸. We found a significantly inferior clinical outcome in patients over 65 years of age. Fracture type distribution was similar between the under and over 65’s. Moonot et al., demonstrated no significant difference in functional outcome between under and over 65 year olds at a mean follow up of 11 months post PHILOS plate fixation ¹⁰. We recorded 2 cases of non-union and 1 case of AVN in the over 65 group. The inferior functional outcome and complications in the elderly population is probably multifactorial, combining both lower strength and reduced range of motion, with a more tenous blood supply and healing capacity. We encountered no mechanical failure of the plate and screws. The use of local adjuvants, such as bone graft or bone graft substitutes at the time of surgery, particularly when poor bone stock is encountered, may well improve the rate of union and has been advocated by others ^3,10.

There was no statistically significant difference in clinical outcome between those who had restoration of their humeral head-neck angle to greater than 90 degrees at the time of surgery and those that did not. As with all locking plates, fracture reduction must be achieved prior to plate application, this can be technically demanding. We achieved this in only 17 of our cases (54%). It has been shown that unstable proximal humeral fractures have a tendency towards varus collapse even in the presence of locking plate fixation. This can lead to varus deformity with impingement and potential screw cut-out. While we have not encountered this problem to date, we advocate optimal restoration of the head-neck angle to guard against this potential complication.

The fact that 7 (22.5%) of our patients required a second procedure following PHILOS plate fixation is a cause of concern. Three of these re-operations were as a result of technical error. In one case a screw was left too long, and in the two other cases the plate was placed in an excessively superior position causing symptomatic impingement. The reported rate of complications following PHILOS plate fixation is high, Owlesy et al., reported a radiographic complication rate in 36% of their patients, with a 43% rate of cut-out in patients over 60 years of age ⁵. Moonot  et al reported significant complications in 21% of their cases ¹⁰. Of the 3 patients in this study who  developed a symptomatic non-union 2 were over 65years of age and had sustained a complex fracture type. A hemiarthroplasty in this situation is an option, the possible benefits of which include; a single operation, excellent pain relief, reasonably good function and no potential for non-union or avascular necrosis ³. However the results obtained in recent studies of hemiarthroplasties for trauma have been mixed ^11,12,13. Problems with strength, function, range of motion, neurological deficits, reoperations and displacement of both the prosthetic head and tuberosities have all been reported ^11,13.

Although the number of patients in our study was relatively small and it was not a randomised controlled study the results demonstrate both the potential benefits and problems with the PHILOS plate. We obtained both good functional results and  bone healing in the vast majority of our patients. There was no statistical difference in functional outcome between the fracture types at a minimum of 18 months post-operatively. Patients under 65 years of age had a significantly better outcome. The PHILOS plate is a useful addition to the armamentarium of the trauma surgeon, however we caution all surgeons on the high potential for complications and re-operations with its use.

Reference :

1. Badman BL, Mighell M. Fixed-angle locked plating of two-, three-, and four-part proximal humerus fractures. J Am Acad Orthop Surg 2008; 16:294-302

2. Baron JA, Barrett JA, Karagas MR. The epidemiology of peripheral fractures. Bone 1996;18-3:209-213

3. Nho SJ, Brophy RH, Barker JU et al. Management of proximal humeral fractures based on current literature. J Bone Joint Surg Am 2007; 89-3:44-58

4. Robinson CM, Page RS, Hill RM et al. Primary hemiarthroplasty for treatment of proximal humeral fractures. J Bone Joint Surg Am 2003;85:1215-23

5. Owsley K, Gorczya JT. Displacement/Screw cutout after open reduction and locked plate fixation of humeral fractures. J Bone Joint Surg Am 2008;90:233-40

6. Muller ME, Nazarian S, Koch P et al. The comprehensive classification of fractures of long bones. Springer Verlang Berlin 1990

7. Neer CS. Displaced proximal humeral fractures. Part 1. Classification and evaluation. J Bone Joint Surg Am 1970;52:1077-89

8. Beaton DE, Wright JG, Katz Jn. Development of the QuickDASH: comparison of the three item-reduction approaches. J Bone Joint Surg Am 2005;87:1038-46

9. Kannus P, Palvanen M, Niemi S et al. Increasing number and incidence of osteoporotic fractures of the proximal humerus in elderly people. BMJ 1996;313:1051-2

10. Moonot P, Ashwood N, Hamlet M. Early results for treatment of three- and four-part fractures of the proximal humerus using the PHILOS plate system. J Bone Joint Surg Br 2007;89-B:1206-9

11. Boileau P, Krishnan SG, Tinsi L et al. Tuberosity malposition and migration: reasons for poor outcomes after hemiarthroplasty for displaced fractures of the proximal humerus. J Shoulder Elbow Surg 2002; 11:401-412

12. Christoforakis JJ, Kontakis GM, Katonis PG et al. Shoulder hemiarthroplasty in the management of humeral head fractures. Acta Orthop Belg 2004; 70:214-8

13. Phillips NJ, Ali A, Stanley D. Treatment of primary arthritis of the elbow by ulnohumeral arthroplasty. J Bone Joint Surg Br 2003;85-B:347-50

This is a peer reviewed paper 

Please cite as: Michael Leonard: The use of locking plates in proximal humeral fractures: comparison of outcome by patient age and fracture pattern.

J.Orthopaedics 2009;6(3)e2

URL: http://www.jortho.org/2009/6/3/e2

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