Continuous external compression for the treatment of humeral pseudarthrosis: a single center experience

Humeral pseudarthrosis are common with a non-union rate after fracture between 8% and 13%. Several operative methods have been described for the treatment of humeral pseudarthrosis. The aim of this study was to assess a new approach based on compression using a monoplane external fixator without graft. This study was conducted in the Department of Orthopedic Surgery, and Traumatology of Habib Bourguiba University Hospital in Sfax-Tunisia between April 2009 and September 2018. Fifty-eight patients were operated on using a dynamic monoplane axial fixation device with continuous compression by manipulating the compression system of the fixator. All the cases were evaluated according to the modified Stewart and Hundley classification. The fracture was located in the middle third in 53.4% of the cases. The pseudarthrosis was hypertrophic in 34.5% of the cases. Fifty-four patients were treated with this method as a first cure of non-union and four patients had previously a first cure for their pseudarthrosis. We noted 11 septic pseudarthrosis. The average follow-up was 47.2 months. We obtained consolidation in 98% of the cases. The average consolidation time was 5.1 months. Based on the modified Stewart and Hundley criteria, 75.8% had very good results. This study highlights that a continuous external compression is effective in the treatment of non-unions, as it allows consolidation without opening the pseudarthrosis site and without bone grafting while having satisfactory anatomical and functional results.


Introduction
Humeral shaft fractures represent 1% of skeletal fractures, with a high rate of bone healing. However, unfavorable evolutions are not exceptional, and humeral pseudarthrosis ranges from 8% to 13% [1,2]. Several operative methods were described in the literature for treatment of humeral shaft pseudarthrosis. The dynamic external fixation with bone graft is classically used [3]. The objective of this paper was to assess the evolution of patients with humeral pseudarthrosis who underwent external continuous compression without bone grafting.

Methods
This study was conducted in the orthopedic surgery department in   Fifty-four patients were treated with continuous external compression as a first cure of non-union and four patients had previously a first cure for their pseudarthrosis and were treated with this method after the failure of the first cure. Good alignment and bone contact were checked with intraoperative radioscopy. The average recovery period was 47.2 months, with extremes ranging from 12 to 102 months. We obtained a consolidation for 98% of the pseudarthrosis (Figure 1).
Only one case did not consolidate, including a sepsis on the pins. The average consolidation time was 5.1 months with extremes ranging from 2 to 10 months ( Table 2). We noted 11 sepsis on pins, 10 of which evolved well after antibiotic treatment. There were no neurological complications, or algodystrophy. Based on the modified Stewart and Hundley criteria, we found 75.8% of very good results, 17.2% of good results, 5.2% of fairly good results, and 1.8% of poor result ( Figure 2).

Discussion
Compression is the principle adopted in our surgical procedure for the non-union of long bones. Using a compression plate is the only technique allowing a good stabilization of the non-union, while performing a bone graft is essential for consolidation. However, in this type of treatment, bone graft seems to play a crucial role. Healy et al. [5] reported 45% of failures by screwed plates without bone graft. Moreover, several articles reported that consolidations could only be obtained by grafting without any modification of the osteosynthesis. Interestingly, the isolated graft supply partly explains the excellent results on non-union cures by plate, bone graft sometimes being considered as an "adjuvant" to the treatment already carried out [6]. Also, we obtained a 98% consolidation rate with the use of screwed plate associated with spongy graft as shown in Table 3 [3,[5][6][7][8][9][10][11]. Centromedullary nail fixation preserves periosteal vascularity and decreases the rate of radial paralysis and infection.
However, this technique is controversial due to the high rate of failure according to several studies as displayed in Table 4 [8,[12][13][14][15].
Several hypotheses could explain these failures, like the insufficiency of primary stability or the impairment of the endomedullary vascularization of the humerus [14]. The Ilizarov external fixator should allow stable fixation, possible correction of the reduction and compression of the pseudarthrosis site [16,17]. Table 5  The only limit to this technique is sepsis on pins.

Conclusion
The treatment of humeral pseudarthrosis with monoplane external fixator with compression seems effective regarding the low incidence of complications and the high rate of bone healing. This method is a good indication in the treatment of humeral pseudarthrosis and probably long bone pseudarthrosis in general.

What is known about this topic
• Humeral pseudarthrosis are not uncommon; • Their treatment is not unanimous; • Many surgical procedures are proposed including compression by plate associated with bone graft.

What this study adds
• External continuous compression is an efficient and reliable method; • External continuous compression is easy to do and at low complication rate; • External continuous compression gives excellent functional results.

Competing interests
The authors declare no competing interests.     Table 4: results of the treatment of non-union with nail Table 5: results of the treatment of non-union with an Ilizarov type external fixator

Consolidation time (months) Average
Type of non-union Atrophic 6.6