Arthroscopy-assisted reduction of impression fracture of thehumeral head: A case report

Satoshi Kato, MD,a Takashi Kobayashi, MD,b Yukio Gonoji, MD,a and Shinjiro Amaya, MD,a

Fukui and Kanazawa, Japan

Impression fracture of the humeral head is rare andcommonly accompanies posterior dislocation of theshoulder, which is often missed on the initial examina-tion. It is possible for this type of fracture to be managedby arthroscopy, similar to tibial plateau fractures, if theimpacted articular cartilage is not severely damaged.This case report describes, for the first time, a case ofarthroscopically reduced impression fracture of the hu-meral head resulting from electrically induced muscularcontraction.

CASE REPORTA 44-year-old man presented with severe pain in both

shoulders. He reported exposure to a 200-V current froma machine. His upper extremities were in a flexed positionwhile touching the machine with his hands when he expe-rienced an electrical shock and was unable to release him-self for several seconds. When he managed to releasehimself, he fell down, hitting his right shoulder on theground.

On physical examination, pain in the left shoulder wasmore severe than that in the right, which had a contusion,and the patient could not raise the left arm. His skin wasnormal without evidence of burn. There were no apparentmotor or sensory nerve deficits. The cervical spine andthoracic spine were not tender, and there was full rangeof motion of the neck. There was no external evidenceof injury to the head, thorax, abdomen, or lower extrem-ities.

Plain radiographs did not show any change in the rightshoulder, but those of the left shoulder showed an impressionfracture of the humeral head in external rotation and a com-

From the aDepartment of Orthopaedic Surgery, Fukui-ken SaiseikaiHospital, Fukui, and bDepartment of Orthopaedic Surgery, KKRHokuriku Hospital, Kanazawa. Dr Kato is currently affiliatedwith the Department of Orthopaedic Surgery, Kanazawa Univer-sity School of Medicine, Kanazawa, Japan.

Reprint requests: Satoshi Kato, MD, Department of OrthopaedicSurgery, Kanazawa University School of Medicine, 13-1 Takara-machi,Kanazawa,920-8641, Japan (E-mail: inji@par.odn.ne.jp).

J Shoulder Elbow Surg 2008;17:e11-e14Copyright ª 2008 by Journal of Shoulder and Elbow Surgery

Board of Trustees.1058-2746/2007/$34.00doi:10.1016/j.jse.2007.06.009

minuted fracture of the lesser tuberosity in internal rotation(Figure 1). Computed tomography (CT) scan clearly demon-strated that the anteromedial impression involved approxi-mately 25% of the articular surface and was 30 mm indiameter and 5 mm in depth (Figure 2). We planned an ar-throscopic procedure to reduce the fracture and evaluate theextent of associated soft-tissue injury. The interval betweeninjury and arthroscopy was 2 weeks.

With the patient in the lateral decubitus position, the ar-throscope was placed into the posterior portal to visualizethe lesion and debride the hemarthrosis and free osteo-chondral fragments by use of an arthroscopic probe andshaver in the anterior portal. An impression fracture withhealthy articular cartilage was identified. There was minorbleeding in the subscapularis tendon, but there was notany evidence of damage to the glenoid or the posteriorcapsule. Arthroscopic reduction was performed as for tib-ial plateau fractures.3,7 An intra-articular guide was in-serted into the center of the depressed articular portion ofthe fracture with the tibial guide used in ligamentous recon-struction. The guide pin protruded through the depressedsurface to ensure accurate positioning (Figure 3). The cor-tical bone on the lateral side of the proximal humerus wasreamed with a cannulated reamer through the guide. Thehumeral bone tunnel was then established, and cancellousbone was obtained with a hollow trephine cutter (8 mm indiameter). Elevation of the depressed articular surface wasperformed with a bone tapper through the tunnel. Duringfracture reduction, the depressed articular surface washeld with a periosteal elevator through the anterior portalto prevent overcorrection (Figure 4). After reduction, betatricalcium phosphate (bTCP) granules were placed to fillthe tunnel, and the previously obtained autogenous cancel-lous bone was compacted over them. After surgery, eleva-tion of the arm was not allowed for 3 weeks, after whichthe patient began physiotherapy. At 2 months of follow-up, the plain radiograph and CT scan showed excellentreduction (Figure 5). At 1 year of follow-up, the functionalresult was excellent, there was no pain, and the range ofmotion was almost full with mild restriction of internal rota-tion to T10.

DISCUSSIONImpression fracture of the humeral head is commonly en-

countered with posterior dislocation of the glenohumeraljoint. There are 3 mechanisms for the dislocation: a directforce to the anterior shoulder pushing the humeral head

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e12 Kato et al J Shoulder Elbow SurgMay/June 2008

Figure 1 Plain radiographs of the left shoulder showed an impression fracture of the humeral head (arrow) in exter-nal rotation (A) and a comminuted fracture of the lesser tuberosity (arrow) in internal rotation (B).

Figure 2 A and B, CT scans showed that the anteromedial impression involved approximately 25% of the articularsurface.

out posteriorly; an indirect force applied through the upperextremity to the shoulder particularly when the upper extrem-ity is in flexion, adduction, and internal rotation; and violentmuscle contraction by electrical shock or seizure. In our pa-tient, there was no posterior dislocation of the shoulder oninitial examination, but we assumed that a posterior sublux-ation of the shoulder had temporarily occurred when he wasexposed to the electrical shock with his upper extremity ina flexed position, and the impressed articular surface wasa reverse Hill-Sachs lesion. The fracture of the lesser tuberos-

ity was an avulsion fracture involved with contraction of thesubscapularis tendon or posterior displacement of the hu-meral head.

To treat this fracture, simple closed reduction of a posteriordislocation can be sufficient when the impression defect issmall and the lesion is recognized early, but if the impressiondefect involves more than 25% of the articular surface, surgi-cal stabilization is recommended.4,8 Although the literaturedescribes several surgical options, most are based on de-tachment of the subscapularis or more complex techniques

J Shoulder Elbow Surg Kato et al e13Volume 17, Number 3

Figure 3 A and B, The guide pin was allowed to protrude through the impressed surface to ensure accurate posi-tioning.

Figure 4 A, Elevation of the impressed articular surface was performed with a bone tapper through the tunnel. B,During fracture reduction, the impressed articular surface was held with a periosteal elevator to prevent overcorrec-tion.

that change the glenohumeral anatomy even more. Osteo-chondral allografting of the humeral defect may be prefera-ble for larger defects.5,6 Recently, open surgical elevation ofan impression in the articular surface was reported.2 In thiscase, the impression of the articular surface was not largeor comminuted on CT scan, and we ascertained by arthros-copy that the articular cartilage was healthy. Therefore, weattempted an arthroscopic elevation and achieved a goodresult.

Alamo et al1 reported that a case of locked posterior dis-location of the shoulder was successfully treated by arthro-scopic removal of an intra-articular loose body andflattening of the impression fracture of the humeral head,but to our knowledge, there are no previous reports describ-ing an impression fracture of the humeral head reduced byan arthroscopic procedure. This arthroscopic procedurecan be effective in patients with impression fractures of thehumeral head given the following criteria: (1) fresh fracture,

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Figure 5 Plain radiograph (A) and CT scan (B) 2 months after surgery showed excellent reduction of the impressionfracture (arrows).

(2) healthy articular cartilage, and (3) small or medial de-fect. It is best for a defect involving more than 25% of the ar-ticular surface, but if the criteria are met, arthroscopicreduction may be tried for those involving less than 25%,along with arthroscopic assessment of associated soft-tissueinjury and washing out of hemarthroses and unstable osteo-chondral fragments.

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