Sternomanubrial instability is a rare clinical finding, with very limited evidence characterizing any progression to degenerative joint changes. Because of its infrequent nature, there is not much information on this condition in the literature.
The sternomanubrial joint has a symphyseal-type articulation, with both sides of the joint covered with hyaline cartilage. A small, well-fixed fibrocartilage disc exists between the two joint surfaces and acts to stabilize the joint additionally. The sternomanubrial joint is strengthened by anterior and posterior fibrous ligaments, which extend across the joint from the manubrium to the body. In the normal joint, minimal motion is present.
Sternomanubrial injury is generally related to high-energy trauma, and is usually associated with a fracture, dislocation, or a fracture-dislocation of the sternum and/or manubrium1-4. Some case reports exist on the development of a painful degenerative sternomanubrial joint after a history of minor trauma5,6. With little published data, it is a challenge to treat a patient with sternomanubrial pain. If there is a displaced fracture, dislocation, or fracture-dislocation, treatment is more straightforward. As with most fractures or dislocations that cannot be managed by closed means, operative reduction and stabilization is currently recommended3. However, options for managing the patient with an arthritic sternomanubrial joint are less clearly established. Conservative measures, including physical therapy and anti-inflammatory medication, have poor reported efficacy in improving outcomes, and surgical treatment, including arthrodesis, is often necessary2,6,7. Fixation techniques for arthrodesis have utilized sutures, bone staples, and plate/screw constructs, but because of the limited number of patients, no superior technique has emerged.
We present a patient with chronic sternomanubrial instability and pain after an athletic injury. He was informed that data concerning the case would be submitted for publication, and he provided consent.
A twenty-one-year-old otherwise healthy man initially presented to our orthopaedic clinic with a one-year history of chronic anterior thoracic pain. He had sustained a low-energy compression injury during competitive wrestling, and all conservative treatment, including anti-inflammatory medication and cessation of wrestling, was unsuccessful. The symptoms included a chronic, aching pain that prevented him from working, as well as difficulty sleeping at night secondary to the discomfort.
On physical examination, no visible gross deformity was noted, but there was tenderness over the sternomanubrial joint, with obvious instability during palpation. Pain was present with any deep inspiration, coughing, or any contraction of the pectoralis major muscles. No pathological findings were noted during evaluation of the bilateral shoulder girdles and upper extremities or during a thorough neurovascular examination. To evaluate for concomitant rheumatological conditions, a screening laboratory evaluation was performed. Results were negative for pertinent findings, including complete blood-cell count, erythrocyte sedimentation rate, antinuclear antibodies, rheumatoid factor, and C-reactive protein level.
Initial radiographic evaluation revealed sternomanubrial widening and joint irregularity (Fig. 1). A computed tomography (CT) scan was obtained to better characterize the sternomanubrial joint and evaluate for any other causes of the pain (Figs. 2-A and 2-B). A preoperative electrocardiogram demonstrated no cardiac abnormalities that required additional workup.
Because of the recalcitrant pain from the sternomanubrial instability, the patient underwent formal sternomanubrial arthrodesis. We used a multidisciplinary approach, and a cardiac surgeon actively performed the procedure. We believe it is necessary to have an experienced cardiothoracic surgeon present in case of iatrogenic injury to the mediastinum or great vessels. A 4-cm midline incision centered over the sternum was made and exposed to bone. The sternomanubrial diastasis was initially noted, and frank instability of the joint was apparent with gentle manipulation of the two segments. Remaining articular cartilage was removed from each side of the joint, and a 1-cm autogenous tricortical anterior iliac crest graft, which was carefully contoured with a rongeur and bone file, was placed into the joint. A titanium H-style sternal plate (Synthes, Paoli, Pennsylvania) was contoured to fit the patient (Fig. 3). Self-drilling, self-tapping locking screws were then inserted after a small reduction tenaculum was used to provide compression anteriorly across the arthrodesis site. The screw lengths were measured preoperatively from the CT scan, and they were verified intraoperatively with use of a caliper. Once the bone graft and implants were in place, the wound was closed in a layered fashion. The patient was admitted overnight for observation and was discharged in stable condition the following day. Immediate postoperative radiographs are shown in Figures 4-A and 4-B.
The postoperative course was largely uneventful, with continued improvement in pain in the immediate postoperative period. For the first six weeks after surgery, the patient was limited to no lifting of more than ten pounds with either hand and no overhead activity. No braces or slings were utilized. He then began shoulder and scapulothoracic range-of-motion exercises under the guidance of a physical therapist, with a gradual increase of upper-extremity weight-bearing over the ensuing four weeks. A second CT scan that was obtained four months postoperatively revealed a solidly fused sternomanubrial joint (Fig. 5). The patient was able to return to work and recreational sporting activity without substantial pain, and only experienced mild chest discomfort. At eight months postoperatively, he denied any dyspnea, dysphagia, or implant prominence. No implant removal was scheduled or planned.
Sternomanubrial pain is an extremely rare condition; there is a paucity of literature describing its diagnosis and management. In reviewing the available literature on this topic, we found only case reports and small case series. The majority of the cases reported in the literature are related to pain or displacement after sternal fractures1,3, with sternomanubrial dislocations and late instability reported in a sporadic manner2-5. Recommendations regarding treatment algorithms are largely absent; successful sternomanubrial fixation methods that have been reported include plate and screw constructs, large nonabsorbable sutures, and surgical staples3-6.
Nikas et al. described a malunited fracture of the sternomanubrial junction that underwent an open osteotomy with soft-tissue transfer2. Stainless steel plates and screws were used to stabilize the osteotomy; the patient was reported to have osseous union with minimal symptoms. Lemaitre et al. reported successful use of polydioxanone ropes (PDS; Ethicon, Somerville, New Jersey) for stabilization of acute, traumatic sternomanubrial joint injuries via an open exposure5. This patient was also reported to have no issues with immediate or delayed instability. El Ibrahimi et al. described fixation of traumatic sternomanubrial dislocations with heavy staples, similar to those used in epiphysiodesis4. Their patient appeared to be doing very well at the most recent follow-up, with no subjective instability or signs of radiographic loosening. Most recently, Gloyer et al. reported on the successful treatment of three patients with traumatic sternomanubrial dislocations or sternal fractures with a single 3.5/4.0-mm fixed angle plate; all achieved uneventful union3. In all of these case reports and series, the surgical procedures were indicated for pain relief and to prevent cardiopulmonary dysfunction. All of the patients in the studies had improvement and uneventful healing without complications.
Associated patterns of sternomanubrial injuries are not frequently reported in the literature, but they appear to be more common in high-energy trauma. The most well-described series of sternal fractures was recently reported by Recinos et al., with a review of 125 patients with sternal fractures over a ten-year period8. The most common associated injury in this series was rib fractures (49.6%); cardiac contusions (8.0%) and thoracic aortic injuries (4.0%) were also relatively common. To the best of our knowledge, there are no similar reports in the literature regarding associated injuries in sternomanubrial instability caused by low-energy trauma (the case reports and series noted above did not include this information).
Conservative treatment of sternal fractures is reported more frequently in the literature. In these cases, gradual return of activity and weight-bearing has allowed for excellent patient outcomes8. On the other hand, conservative treatment for sternomanubrial instability is poorly characterized, with the various reports and series noting the use of physical therapy, anti-inflammatory medication, and narcotic pain medication1-7. To our knowledge, no direct comparisons between the conservative treatment options have been made, but it appears that conservative treatment with judicious use of activity restriction, physical therapy, and anti-inflammatory medication may be of some use in the first-line treatment for alleviating symptoms.
Our patient is unique because he presented with chronic sternomanubrial instability and pain after an athletic injury. His condition was successfully treated with an arthrodesis utilizing autogenous iliac crest bone graft, with successful clinical and radiographic healing at sixteen weeks postoperatively.
In the rare instance of encountering a patient with a displaced sternal fracture or sternomanubrial dislocation, operative reduction and stabilization has proved to provide adequate radiographic and clinical outcomes3,4. However, patients with chronic sternomanubrial pain are more challenging to treat. We present sternomanubrial arthrodesis as a simple yet potentially reliable method for treating posttraumatic degeneration and instability.