Sport related stress fracture of the clavicle with non-union: Case report and review.

Stress fractures are relatively uncommon sports injuries and when they do occur, are mostly found in the lower limb. Stress fractures of the clavicle are particularly rare, having been described in a number of non-sport related pathologies, such as nervous tics and post radical neck dissection. In sport, there have only been seven cases reported in the literature. We report on a clavicle stress fracture in a 47-year-old male, partaking in recreational weight lifting activities. This is the first reported case of a non-union stress fracture of the clavicle. The patient underwent an open reduction and internal fixation and made a full recovery.

INTRODUCTION

Clavicle stress fractures are particularly rare, with only 16 reported cases.[1-8] They have been described in patients following radical neck dissection,[45] following coracoclavicular ligament reconstruction[4] and few sports-related cases. Two cases have been reported as being idiopathic, with no overt etiology.[38]

Stress fractures are injuries that typically occur in sport and are usually related to overuse.[19] They occur more in the lower as compared to the upper extremity.

We report a case of a clavicle stress fracture non-union secondary to weight-training. This is the first reported case of a sports-related non union stress fracture of the clavicle.

CASE REPORT

A 47-year-old male who had been performing regular weight training for more than ten years, had increased the intensity of training over a two-week period. He subsequently developed pain in his left shoulder. The pain intensified, with symptoms on abduction during daily activities. He consulted with his family physician, who requested an X-ray investigation, which was reported as normal. With the pain not abating, he was referred for a CT scan that revealed a linear defect confirming a stress fracture over the lateral third of the clavicle [Figure 1].

Figure 1

CT scan of left clavicle delineating site of stress fracture (arrowed)

He was treated symptomatically with oral analgesic and anti-inflammatory medication. After several weeks he was prescribed narcotic analgesics for the pain. Four months after the onset of symptoms, despite reduced activity and the use of narcotic analgesics, he continued to have pain and was referred to the authors' sports medicine clinic.

The history confirmed the patient's regular weight training program, usually five to six days a week, with increased intensity prior to the onset of symptoms. The rest of the history was unremarkable.

Clinically there was a tender swelling over the lateral third of the clavicle [Figure 2]. A repeat X-ray confirmed the diagnosis of a hypertrophic non-union stress fracture of the clavicle [Figure 3].

Figure 2

Photograph showing clinical prominence of non-union stress fracture of left clavicle

Figure 3

Radiograph of stress fracture indicating hyperdrophic non-union

The patient was advised to have surgery, which he underwent. At surgery the hypertrophic bone and the non-union were excised. The medulla was opened on both sides using a 4.5 mm diameter drillbit. A seven-hole LCDC plate (Synthes USA) was contoured and applied antero-superiorly across the fracture site [Figure 4]. Compression of the fracture site was achieved. Allomatrix® Injectable Putty (Wright Medical Technology, Arlington, Tennessee, USA), was applied around the fracture site. The post surgery X-rays revealed acceptable reduction and fixation [Figure 5]. Post-operatively a sling was worn for four weeks and thereafter the patient underwent rehabilitation. Serial radiography and clinical follow-up was performed. The final follow-up was at 11 months from the non-union surgery.

Figure 4

Intraoperative photograph of an LCDC plate over fracture site

Figure 5

Postoperative radiograph of internal fixator over fracture

Range of movement and strength were clinically symmetrical at final follow-up. No scoring system was used.

Tenderness was mild, but present over the plate while it was in situ. This prompted removal of the plate. Local tenderness resolved thereafter.

Aerobic exercise (running and cycling) was permitted at four months following the non-union surgery. Light, but progressive gym activities were permitted six weeks later, as the patient did not experience any adverse effect from the aerobic activity.

The clinical outcome was therefore deemed favorable, with the patient recovering fully from the injury.

DISCUSSION

The clavicle articulates with the acromion and the sternum. With contraction, the pectoralis major and deltoid muscles produce a downward force, whilst with the trapezius and sternocleidomastoid muscles will oppose this movement. Repetitive activation of these muscles may result in enough strain to overcome remodeling and create micro architecture disruption, eventually leading to a stress fracture.[2]

Stress fractures account for approximately 2% of all reported sports injuries.[10] Lower limb stress fractures are more common than upper extremity stress fractures and may be diagnosed on history, physical examination and imaging (including radiographs, bone scans, MRI and CT scan).[9] Those stress fractures that do occur in the upper limb are usually related to upper-limb dominated activities, such as throwing sports, swimming, baseball pitching and tennis.[1]

Clavicle stress fractures are particularly rare, with only 16 cases reported and only seven related to sporting activities [Table 1]. In patients diagnosed with clavicle fractures, the differential diagnosis should include traumatic or pathological fracture, neoplasm, infection, metabolic bone disease and bone dysplasia.[3]

Table 1:

Sprots related clavicle stress fracture

Clavicle stress fracture (n)	Authors	Sport
1	Abbott, Hannafin, 2001[2]	Lightweight rower
1	Roset-Llobet, Salo-Orfila, 1998[11]	“Human tower” building
1	Fallon, Fricker, 2001[4]	Gymnast
1	Shellhas, Glaser, Drezner, 2004[5]	Weightlifter
1	Wu, Chen, 1998[12]	Baseball player
1	Waninger, 1997[13]	Diver
Total n = 7	Adolfsson, Lysholm, 1990[14]	Javelin thrower

We report a case of clavicle stress fracture with non-union in a middle-aged male after accelerated weight training. This case is particularly unique in that not only is it one of a rare form of stress fracture, it is only the second reported case related to weight lifting[5] and the first reported sports-related stress fracture with resultant non-union.

Clinicians treating athletes should have a high index of suspicion because although rare, clavicle stress fractures should feature in the differential diagnosis of shoulder or clavicle pain.[14]