- Email: [email protected]
Osteolysis of the Distal Clavicle: Serial Improvement and Normalization of Acromioclavicular Joint Space with Conservative Care
OSTEOLYSIS OF THE DISTAL CLAVICLE: SERIAL IMPROVEMENT AND NORMALIZATION OF ACROMIOCLAVICULAR JOINT SPACE WITH CONSERVATIVE CARE Brooke L. Gajeski, DC,a and Norman W. Kettner, DCb
ABSTRACT Objective: To discuss a case of osteolysis of the distal clavicle (ODC) in a 29-year-old male chiropractic student who showed interval radiographic and clinical evidence of healing. Clinical Features: The patient complained of intermittent left-sided shoulder pain of 8 months’ duration that was exacerbated while performing spinal-manipulative procedures. A radiographic examination showed changes consistent with osteolysis involving the distal clavicle. Intervention and Outcome: A conservative treatment regimen of physiotherapy, nutritional supplementation, and activity modification resulted in an interval reduction in symptomatology and radiographic findings on serial examinations, ultimately resolving both abnormal clinical and radiographic findings after approximately 14 months of treatment. We specifically observed normalization of the acromioclavicular (AC) joint dimension. Conclusions: In contrast to the posttreatment radiographic outcome seen in our patient, ODC classically does not result in complete resolution of radiographic findings or normalization of AC joint dimension, and such radiographic normalization of joint space is currently not reported in the literature. This case report serves to document and to show this unique occurrence. (J Manipulative Physiol Ther 2004;27:e12) Key Indexing Terms: Clavicle; Osteolysis; Acromioclavicular Joint; Trauma; Chiropractic
INTRODUCTION
C
hronic pain localized to the acromioclavicular (AC) joint is, in most cases, caused by primary osteoarthritis, secondary osteoarthritis, or osteolysis of the distal clavicle.1 Osteolysis of the distal clavicle (ODC), however, is frequently overlooked as a cause of shoulder pain in both acute and chronic shoulder injuries, in patients without trauma, and, in rare cases, patients with systemic disease. Evolution of ODC is frequently indolent and may represent a diagnostic dilemma for the clinician.
a
Diagnostic Imaging Resident, Department of Radiology, Logan College of Chiropractic, Chesterfield, Mo. b Chair, Department of Radiology, Logan College of Chiropractic, Chesterfield, Mo. Submit requests for reprints to: Norman W. Kettner, DC, Logan College of Chiropractic, Chair, Department of Radiology, PO Box 1065, 1851 Schoettler Road, Chesterfield, MO 63006-1065 (e-mail: [email protected]). Paper submitted December 2, 2002; in revised form January 2, 2003. 0161-4754/$30.00 Copyright D 2004 by National University of Health Sciences. doi:10.1016/j.jmpt.2004.06.009
Prompt recognition and diagnosis of the entity are of utmost importance in determining the success of conservative care. A delayed diagnosis typically results in a permanently widened AC joint with varying degrees of mechanical dysfunction and pain. Early diagnosis and treatment have been shown to successfully halt the osteolysis process in some cases and result in varying degrees of reversal and healing; however, complete reversal, with the AC joint reverting to normal dimension, has not been reported in the literature. The following case report is unique in that it displays radiographic and clinical interval healing with reversal of osteolysis-related changes and normalization of the AC joint space dimension in an active young male suffering from ODC of the left distal clavicle. Clinical, pathologic, and imaging features are reviewed, as well as current treatment regimes and outcomes.
CASE REPORT A 29-year-old right-handed male chiropractic student complained of constant left-sided shoulder pain that began 8 months prior. The pain began intermittently and progressed 480.e1
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Fig 1. A, Baby-arm view shoulder radiograph. B, AC joint spot photograph from an A-P external rotation shoulder radiograph. In A, lytic and cystic changes are present involving the distal clavicular cortex, with an intra-articular gas collection in the AC joint (arrow). In B, abnormal widening of the AC joint is noted (arrows).
Fig 2. AC joint spot photograph from an AP external rotation shoulder radiograph taken 7 months later. There is reduction in the number and size of the previously noted subchondral cysts, with interval improvement in the distal clavicular cortical definition. The AC joint width has normalized to 3.0 mm (arrows).
Fig 3. AC joint spot photograph from an AP external rotation shoulder radiograph taken 14 months after the initial study. There is continued interval reduction in the size of the subchondral cysts, with nearly normal cortical consolidation. The AC joint width remains unchanged from the previous examination.
to constant pain by the time he sought care. He found the pain was exacerbated while performing spinal-manipulative procedures, especially during side-posture techniques. The patient had been a construction worker for 10 years before university training, mainly hanging drywall during his last 2O years of construction work. He played football for 4 years during high school and was quite active in his youth because he lived on a farm during childhood and adolescence. The patient reported no major health problems or upper extremity trauma and had no medication history. Orthopedic examination was positive, with reproduction of his chief complaint only when performing Apley’s scratch test. The remainder of the physical examination was unremarkable.
Radiographs of the left shoulder (Fig 1) showed irregularity and resorption of the distal clavicular cortical margin with multiple subchondral cysts. Abnormal widening of the joint space to 5.0 mm (normal values: 2.5-4.1 mm in men, 2.1-3.7 mm in women)2 was also noted with a small gas collection in the joint space (Fig 1). The patient was told to restrict provocative activities to allow healing via conservative measures. He adopted a modification of his adjusting technique and also discontinued performance of side-posture pelvic manipulative techniques. An immediate conservative adjunctive therapy regimen was also initiated, consisting of AC joint electrical stimulation twice per week, upper extremity strengthening exercises, and daily dietary
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supplementation, including multimineral, glucosamine, and chondroitin sulfate. A serial radiographic examination was performed 7 months later and showed reduction in the previously noted osteolysis of the distal clavicle. Persistence of subchondral cysts was noted, although to a lesser degree, and the subchondral clavicular cortex showed improved definition (Fig 2). The AC joint space showed normalization, measuring 3.0 mm (Fig 2). Intra-articular gas was still visualized. During the 7 months after the initial radiographic examination, he experienced decreased frequency and severity of his pain, with acute flare-ups occurring only when he was required to perform frequent spinal manipulation. The patient continued his prescribed conservative therapy regime for approximately 7 more months, at which time a third left-shoulder radiographic series was performed. Continued interval improvement was again shown with nearly normal cortical consolidation and reduction in the subchondral cystic changes (Fig 3). The normal joint space and the intra-articular gas remained unchanged from the previous examination. After the third radiographic examination, the patient once again continued his conservative therapeutic regimen and has since experienced continued improvement, with extended periods of time without symptoms.
Table 1. Differential diagnosis of lysis, erosion, or defects of the distal clavicle
DISCUSSION
Clinical Features
Pathogenesis and Differential Considerations Osteolysis of the distal clavicle is progressive resorption of the outer end of the clavicle resulting from both traumatic and atraumatic causes. Acromioclavicular joint dislocations and fractures of the clavicle are among the common acute shoulder injuries resulting in posttraumatic ODC.3 More frequently, however, the responsible trauma is relatively minor and not associated with fracture or dislocation.4,5 Overuse, or stress-induced, ODC is observed most frequently in manual laborers, weight lifters, and athletes involved in throwing activities. Idiopathic, or atraumatic, ODC is quite rare, with only 3 reports of the entity represented in the literature.6 The cause and pathogenesis of posttraumatic and stressinduced ODC are still unclear. Stress-induced ODC is most likely the result of repetitive microtrauma, leading to subchondral stress fractures with synovial hyperemia and subsequent bone resorption.7 Other etiologic theories of both posttraumatic and stress-induced ODC include autonomic nerve dysfunction leading to abnormalities in blood supply, terminal nerve or vascular damage, hyperplastic synovial invasion, and ischemic necrosis.8-11 The clinical and radiographic abnormalities are frequently identical in both varieties. Additional differential considerations for lysis, erosion, or defects involving the distal clavicle may be recalled by using the mnemonic bSHIRT Pocket.Q2,12 We propose
M ultiple myeloma, Metastasis y S H I R T
urgical, Scleroderma yperparathyroidism nfection (pyogenic, tuberculous) heumatoid arthritis, Rickets rauma (ODC caused by microtrauma)
P o C k E T
yknodysostosis, Progeria leidocranial dysplasia osinophilic granuloma rauma (ODC caused by macrotrauma)
ODC, Osteolysis of the distal clavicle.
expanding the mnemonic to bMy SHIRT Pocket,Q with the addition of other differential considerations (Table 1).2 One may associate this mnemonic with seeing the distal clavicle by looking down into the shirt pocket. Differential diagnosis is ultimately obtained via clinical, imaging, or laboratory evaluation.
Clinical symptoms frequently present with unilateral, less commonly bilateral, dull, achy shoulder pain that arises weeks to months after acute shoulder injury but insidiously with slow onset in the stress-induced form of ODC.3,9,10 Focal pain and AC swelling with or without crepitus are common features in weight lifters and athletes afflicted with the stress-induced variety.13-15 Exercises such as the bench press or push-ups frequently cause acute exacerbation, along with cross-body adduction and greater than 908 abduction of the arm. The process is usually unilateral; however, bilateral symptoms are frequent, occurring in as many as 20%.8
Imaging The diagnosis of ODC is ultimately radiographic in nature, with secondary consideration of the patient’s clinical symptoms. The natural course of ODC varies in time but is consistent in evolution with the pathologic process divided radiographically into lytic and reparative phases.11 Optimal radiographic examination of the AC joint is performed in the frontal projection with a 158 cephalad tube tilt,8 which was not used in this case since a shoulder series was requested. Early radiographic findings of the lytic phase may occur as early as 2O to 4 weeks and include osteopenia, cortical margin resorption, subchondral cystic changes, and subsequent joint space widening,1,10,16 all features that were shown in our patient 8 months after the onset of his symptoms. An additional radiographic finding
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seen on initial and subsequent images of our patient was an intra-articular AC joint gas collection. This is a typical finding seen in degenerative joint disease17; however, no reports in the literature have linked this finding to ODC. It is reasonable to assume the intra-articular gas collection seen in the AC joint of our patient most likely represents a concomitant degenerative complication. Continued repetitive stress across the AC joint without intervention may extend the lytic phase of stress-induced osteolysis from 12 to 18 months, resulting in progressive radiolucency of the distal clavicle up to 0.5 to 3.0 cm.10 However, in contrast to posttraumatic ODC, in which extreme bone loss may be seen, tapering of the distal clavicle is seen only very late in the course of stress-induced ODC.9,14 Eventually, the self-limiting nature of the process intervenes, and the lytic phase stabilizes, with gradual changes of healing seen in the reparative phase during a 4to 6-month period.3,10 Reparative changes consist of reconstitution of the distal clavicular cortex with a reduction in subchondral cysts, but the AC joint classically remains permanently widened.3,8,9,11 This, however, is in contrast to radiographic findings in our patient, which showed serial healing and reversal of the lytic process, ultimately resulting in an AC joint of normal dimension. Unfortunately, the radiographic changes stated above may be subtle or absent in the early stages of the lytic phase. Findings on additional imaging modalities such as magnetic resonance imaging (MRI) or radionuclide bone scan may delineate occult pathology of ODC not visualized on plain films or further characterize the extent and severity of osseous and soft tissue involvement in traumatic and stress-induced ODC. The identification of ODC in the absence of plain film findings or a clinical history of trauma is very important in a patient who does not respond to a trial of conservative care, because more aggressive therapy may be indicated for pain control and prevention of associated delayed complications.1 MRI is a useful modality for the delineation of soft tissue injuries of the shoulder and the osteolysis process. MRI findings in ODC include soft tissue swelling and synovial hypertrophy or bone marrow edema seen as a decrease in signal intensity on T1 spin echo images and as isointensity or hyperintensity on T2 spin echo images within the clavicular bone marrow and/or surrounding soft tissues.8,10 Intra-articular effusion may also be present, seen as increased intra-articular signal intensity on T2 spin echo images.4 Short tau inversion recovery (STIR) images (fat saturation) are most sensitive in showing edematous changes within the bone marrow and surrounding soft tissues, seen as markedly increased signal intensity on these images.1,8,10 It is important, however, to remember that findings of increased MRI signal intensity on T2 spin echo and STIR images are not specific for ODC.1 Increased T2 signal intensity of the AC joint is not uncommon on MRI, and in the absence of associated AC joint pain, it is usually of no clinical significance.1 Other abnormalities
that accompany increased T2 signal intensity of the distal clavicle on MRI include AC osteoarthritis (50%) (changes similar to Modic type 1 changes seen in degenerative disk disease), recent trauma, rotator cuff tendinopathy or tear, septic and inflammatory arthritis, and neoplasm.1,10 Additional findings of ODC on MRI include subchondral cysts, capsular distention, and cortical thinning and irregularity, which may correlate with plain film findings.1,8,9 Intravenous gadolinium is rarely used in the evaluation of ODC; however, it does confirm some degree of increased vascularity and inflammation, seen as increased signal intensity at the AC joint on T1 fat-suppressed images.4 Radionuclide bone scintigraphy findings of ODC correlate with pathologic changes of hyperemia and osteoblastic activity of subchondral bone, seen as increased angiographic and blood pool phases, in addition to increased focal distal clavicular uptake in the delayed phase.16 Increased radiotracer uptake is seen most commonly on the clavicular portion of the AC joint; however, approximately 30% of patients also have increased activity in the adjacent acromion.8,15 The nonspecificity of the MRI examination of the AC joint mentioned above must also be kept in mind with regard to the scintigraphic examination, as it also applies to this imaging modality.
Treatment Options Treatment methods for ODC are generally driven by symptomatology and disease stage. However, controversy does exist on the course of the disease, with some authors concluding that insufficient treatment predisposes and exaggerates the osteolytic process, whereas others believe the eventual severity of bony damage is predetermined and directly related to the severity of the inciting event.3,11 Most do agree, however, that the natural course of the disease process is not that predictable and that determination of the severity of future clavicular involvement, even with early intervention, is ultimately impossible.10 Early intervention generally will not suppress early manifestations but may result in decreased bone loss and an earlier cessation of osteolysis and clinical symptoms.10,11 Conservative treatment options should be used as long as the patient will comply, with consideration of the patient’s symptoms and functional status. Patients have been treated successfully with conservative methods by eliminating provoking activities, immobilizing the extremity, and using physiotherapeutics.3,15 Corticosteroid injections and oral anti-inflammatory agents have been used with limited success.8,10,15 For those patients who fail conservative care or athletes who refuse to eliminate provoking activities, surgical resection is the procedure of choice. Currently, open resection and arthroscopic techniques are employed in the surgical management of ODC. Open distal clavicular excision was first described in 1902 and popularized in
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the early 1940s by Gurd and Mumford for symptomatic traumatic AC joint pathology.15,18 The open resection technique removes the pathologic articular surfaces, creating a wide enough margin for removal of the osteolytic process in its entirety, and prevents AC abutment during abduction.8 Many authors have since reported satisfactory results with the procedure for both traumatic and nontraumatic painful entities of the AC joint,10,15,18,19 resulting in significant pain relief within 4 to 8 weeks after surgery in most patients.8,18,20 However, not all patients will be able to return to their former athletic or occupational status after surgery due to ongoing functional impairment and limitation of shoulder motion and strength. Outcomes of less invasive arthroscopic approaches to distal clavicular excision have been shown to surpass open clavicular resection in a variety of studies.18,20 Open resection invades the deltotrapezial fascia of the shoulder, weakening the extremity and potentiating postoperative instability.10 The arthroscopic approach differs from the standard open technique in that both the acromion and the clavicle are resected via an indirect bursal or direct superior approach and spares the deltotrapezial fascia.20 Arthroscopic methods have shown a more rapid return to daily living and work activities versus the open approach, with an overall equivalent or superior relief of symptoms and a reduction in postoperative complications.15,20
CONCLUSIONS Osteolysis of the distal clavicle has been described as progressive resorption of the distal clavicle after acute and chronic, stress-induced shoulder injury. The familiarity of clinicians with ODC is of utmost importance, as the entity often presents insidiously and may mimic other shoulder pathology. The history of trauma and positive radiographic evidence clinch the diagnosis, yet specialized imaging, including MRI and bone scintigraphy, may be necessary for early diagnosis and initiation of therapy. Classically, the pathologic process is ultimately self-limiting with or without early therapy and results in a widened AC joint on radiographs along with reduced function of the extremity. This case report highlighted and showed a patient whose radiographs, after aggressive although conservative therapy, showed progressive, serial distal clavicular healing and normalization of joint space dimension. Surgical treatment may be necessary for patients who do not respond to conservative care and/or refuse to modify provocative activities.
REFERENCES 1. Fiorella D, Helms CA, Speer KP. Increased T2 signal intensity in the distal clavicle: incidence and clinical implications. Skeletal Radiol 2000;29:697-702. 2. Yochum TR, Rowe LJ. Measurements in skeletal radiology. In: Yochum TR, Rowe LJ, editors. Essentials in skeletal radiology. Baltimore7 Williams and Wilkins; 1996 p. 185. 3. Reber P, Patel AG, Hess R, Noesberger B. Post-traumatic osteolysis of the distal clavicle. Arch Orthop Trauma Surg 1996;115:120-2. 4. de la Puente R, Boutin RD, Theodorou DJ, Hooper A, Schweitzer M, Resnick D. Post-traumatic and stress-induced osteolysis of the distal clavicle: MR imaging findings in 17 patients. Skeletal Radiol 1999;28:202-8. 5. Murphy OB, Bellamy R, Wheeler W, Brower TD. Posttraumatic osteolysis of the distal clavicle. Clin Orthop 1975; 109:108-14. 6. Hawkins BJ, Covey DC, Thiel BG. Distal clavicle osteolysis unrelated to trauma, overuse, or metabolic disease. Clin Orthop 2000;370:208-11. 7. Brahee DD, Kettner NW. Osteolysis of the distal clavicle: a review. Top Diagn Radiol Adv Imaging 1999;Fall:10-4. 8. Clarke HD, McCann PD. Acromioclavicular joint injuries. Orthop Clin North Am 2000;31:177-87. 9. Mestan MA, Bassano JM. Posttraumatic osteolysis of the distal clavicle: analysis of 7 cases and a review of the literature. J Manipulative Physiol Ther 2001;24:356-61. 10. Levine AH, Pais MJ, Schwartz EE. Posttraumatic osteolysis of the distal clavicle with emphasis on early radiographic changes. Am J Roentgenol 1976;127:781-4. 11. Brunet ME, Reynolds MC, Cook SD, Brown TW. Atraumatic osteolysis of the distal clavicle: histologic evidence of synovial pathogenesis. A case report. Orthopedics 1986;9:557-9. 12. Reeder MM. Bone, joints, and soft tissues. In: Reeder MM. Gamuts in radiology. New York7 Springer-Verlag Inc.; 1993. p. 269. 13. Brahee D, Osborne CA, Burke J, Kettner N, Rehmel D, Gajeski B. The prevalence of osteolysis of the distal clavicle in recreational weight trainers. J Sports Chiropr Rehabil 2001;15: 71-9. 14. Patten RM. Atraumatic osteolysis of the distal clavicle: MR findings. J Comput Assist Tomogr 1995;19:92-5. 15. Cahill BR. Atraumatic osteolysis of the distal clavicle. A review. Sports Med 1992;13:214-22. 16. Sopov V, Fuchs D, Bar-Meir E, Groshar D. Stress-induced osteolysis of distal clavicle: imaging patterns and treatment using CT-guided injection. Eur Radiol 2001;11:270-2. 17. Resnick D. Diagnosis of bone and joint disorders. 4th ed. Philadelphia: W.B. Saunders Company; 2002. p. 1327, 1350, 1408. 18. Petchell JF, Sonnabend DH, Hughes JS. Distal clavicular excision: a detailed functional assessment. Aust N Z J Surg 1995;65:262-6. 19. Scavenius M, Iversen BF. Nontraumatic clavicular osteolysis in weight lifters. Am J Sports Med 1992;20:463-7. 20. Henry MH, Liu SH, Loffredo AJ. Arthroscopic management of the acromioclavicular joint disorder. A review. Clin Orthop 1995;316:276-83.
ABSTRACT Objective: To discuss a case of osteolysis of the distal clavicle (ODC) in a 29-year-old male chiropractic student who showed interval radiographic and clinical evidence of healing. Clinical Features: The patient complained of intermittent left-sided shoulder pain of 8 months’ duration that was exacerbated while performing spinal-manipulative procedures. A radiographic examination showed changes consistent with osteolysis involving the distal clavicle. Intervention and Outcome: A conservative treatment regimen of physiotherapy, nutritional supplementation, and activity modification resulted in an interval reduction in symptomatology and radiographic findings on serial examinations, ultimately resolving both abnormal clinical and radiographic findings after approximately 14 months of treatment. We specifically observed normalization of the acromioclavicular (AC) joint dimension. Conclusions: In contrast to the posttreatment radiographic outcome seen in our patient, ODC classically does not result in complete resolution of radiographic findings or normalization of AC joint dimension, and such radiographic normalization of joint space is currently not reported in the literature. This case report serves to document and to show this unique occurrence. (J Manipulative Physiol Ther 2004;27:e12) Key Indexing Terms: Clavicle; Osteolysis; Acromioclavicular Joint; Trauma; Chiropractic
INTRODUCTION
C
hronic pain localized to the acromioclavicular (AC) joint is, in most cases, caused by primary osteoarthritis, secondary osteoarthritis, or osteolysis of the distal clavicle.1 Osteolysis of the distal clavicle (ODC), however, is frequently overlooked as a cause of shoulder pain in both acute and chronic shoulder injuries, in patients without trauma, and, in rare cases, patients with systemic disease. Evolution of ODC is frequently indolent and may represent a diagnostic dilemma for the clinician.
a
Diagnostic Imaging Resident, Department of Radiology, Logan College of Chiropractic, Chesterfield, Mo. b Chair, Department of Radiology, Logan College of Chiropractic, Chesterfield, Mo. Submit requests for reprints to: Norman W. Kettner, DC, Logan College of Chiropractic, Chair, Department of Radiology, PO Box 1065, 1851 Schoettler Road, Chesterfield, MO 63006-1065 (e-mail: [email protected]). Paper submitted December 2, 2002; in revised form January 2, 2003. 0161-4754/$30.00 Copyright D 2004 by National University of Health Sciences. doi:10.1016/j.jmpt.2004.06.009
Prompt recognition and diagnosis of the entity are of utmost importance in determining the success of conservative care. A delayed diagnosis typically results in a permanently widened AC joint with varying degrees of mechanical dysfunction and pain. Early diagnosis and treatment have been shown to successfully halt the osteolysis process in some cases and result in varying degrees of reversal and healing; however, complete reversal, with the AC joint reverting to normal dimension, has not been reported in the literature. The following case report is unique in that it displays radiographic and clinical interval healing with reversal of osteolysis-related changes and normalization of the AC joint space dimension in an active young male suffering from ODC of the left distal clavicle. Clinical, pathologic, and imaging features are reviewed, as well as current treatment regimes and outcomes.
CASE REPORT A 29-year-old right-handed male chiropractic student complained of constant left-sided shoulder pain that began 8 months prior. The pain began intermittently and progressed 480.e1
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Fig 1. A, Baby-arm view shoulder radiograph. B, AC joint spot photograph from an A-P external rotation shoulder radiograph. In A, lytic and cystic changes are present involving the distal clavicular cortex, with an intra-articular gas collection in the AC joint (arrow). In B, abnormal widening of the AC joint is noted (arrows).
Fig 2. AC joint spot photograph from an AP external rotation shoulder radiograph taken 7 months later. There is reduction in the number and size of the previously noted subchondral cysts, with interval improvement in the distal clavicular cortical definition. The AC joint width has normalized to 3.0 mm (arrows).
Fig 3. AC joint spot photograph from an AP external rotation shoulder radiograph taken 14 months after the initial study. There is continued interval reduction in the size of the subchondral cysts, with nearly normal cortical consolidation. The AC joint width remains unchanged from the previous examination.
to constant pain by the time he sought care. He found the pain was exacerbated while performing spinal-manipulative procedures, especially during side-posture techniques. The patient had been a construction worker for 10 years before university training, mainly hanging drywall during his last 2O years of construction work. He played football for 4 years during high school and was quite active in his youth because he lived on a farm during childhood and adolescence. The patient reported no major health problems or upper extremity trauma and had no medication history. Orthopedic examination was positive, with reproduction of his chief complaint only when performing Apley’s scratch test. The remainder of the physical examination was unremarkable.
Radiographs of the left shoulder (Fig 1) showed irregularity and resorption of the distal clavicular cortical margin with multiple subchondral cysts. Abnormal widening of the joint space to 5.0 mm (normal values: 2.5-4.1 mm in men, 2.1-3.7 mm in women)2 was also noted with a small gas collection in the joint space (Fig 1). The patient was told to restrict provocative activities to allow healing via conservative measures. He adopted a modification of his adjusting technique and also discontinued performance of side-posture pelvic manipulative techniques. An immediate conservative adjunctive therapy regimen was also initiated, consisting of AC joint electrical stimulation twice per week, upper extremity strengthening exercises, and daily dietary
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supplementation, including multimineral, glucosamine, and chondroitin sulfate. A serial radiographic examination was performed 7 months later and showed reduction in the previously noted osteolysis of the distal clavicle. Persistence of subchondral cysts was noted, although to a lesser degree, and the subchondral clavicular cortex showed improved definition (Fig 2). The AC joint space showed normalization, measuring 3.0 mm (Fig 2). Intra-articular gas was still visualized. During the 7 months after the initial radiographic examination, he experienced decreased frequency and severity of his pain, with acute flare-ups occurring only when he was required to perform frequent spinal manipulation. The patient continued his prescribed conservative therapy regime for approximately 7 more months, at which time a third left-shoulder radiographic series was performed. Continued interval improvement was again shown with nearly normal cortical consolidation and reduction in the subchondral cystic changes (Fig 3). The normal joint space and the intra-articular gas remained unchanged from the previous examination. After the third radiographic examination, the patient once again continued his conservative therapeutic regimen and has since experienced continued improvement, with extended periods of time without symptoms.
Table 1. Differential diagnosis of lysis, erosion, or defects of the distal clavicle
DISCUSSION
Clinical Features
Pathogenesis and Differential Considerations Osteolysis of the distal clavicle is progressive resorption of the outer end of the clavicle resulting from both traumatic and atraumatic causes. Acromioclavicular joint dislocations and fractures of the clavicle are among the common acute shoulder injuries resulting in posttraumatic ODC.3 More frequently, however, the responsible trauma is relatively minor and not associated with fracture or dislocation.4,5 Overuse, or stress-induced, ODC is observed most frequently in manual laborers, weight lifters, and athletes involved in throwing activities. Idiopathic, or atraumatic, ODC is quite rare, with only 3 reports of the entity represented in the literature.6 The cause and pathogenesis of posttraumatic and stressinduced ODC are still unclear. Stress-induced ODC is most likely the result of repetitive microtrauma, leading to subchondral stress fractures with synovial hyperemia and subsequent bone resorption.7 Other etiologic theories of both posttraumatic and stress-induced ODC include autonomic nerve dysfunction leading to abnormalities in blood supply, terminal nerve or vascular damage, hyperplastic synovial invasion, and ischemic necrosis.8-11 The clinical and radiographic abnormalities are frequently identical in both varieties. Additional differential considerations for lysis, erosion, or defects involving the distal clavicle may be recalled by using the mnemonic bSHIRT Pocket.Q2,12 We propose
M ultiple myeloma, Metastasis y S H I R T
urgical, Scleroderma yperparathyroidism nfection (pyogenic, tuberculous) heumatoid arthritis, Rickets rauma (ODC caused by microtrauma)
P o C k E T
yknodysostosis, Progeria leidocranial dysplasia osinophilic granuloma rauma (ODC caused by macrotrauma)
ODC, Osteolysis of the distal clavicle.
expanding the mnemonic to bMy SHIRT Pocket,Q with the addition of other differential considerations (Table 1).2 One may associate this mnemonic with seeing the distal clavicle by looking down into the shirt pocket. Differential diagnosis is ultimately obtained via clinical, imaging, or laboratory evaluation.
Clinical symptoms frequently present with unilateral, less commonly bilateral, dull, achy shoulder pain that arises weeks to months after acute shoulder injury but insidiously with slow onset in the stress-induced form of ODC.3,9,10 Focal pain and AC swelling with or without crepitus are common features in weight lifters and athletes afflicted with the stress-induced variety.13-15 Exercises such as the bench press or push-ups frequently cause acute exacerbation, along with cross-body adduction and greater than 908 abduction of the arm. The process is usually unilateral; however, bilateral symptoms are frequent, occurring in as many as 20%.8
Imaging The diagnosis of ODC is ultimately radiographic in nature, with secondary consideration of the patient’s clinical symptoms. The natural course of ODC varies in time but is consistent in evolution with the pathologic process divided radiographically into lytic and reparative phases.11 Optimal radiographic examination of the AC joint is performed in the frontal projection with a 158 cephalad tube tilt,8 which was not used in this case since a shoulder series was requested. Early radiographic findings of the lytic phase may occur as early as 2O to 4 weeks and include osteopenia, cortical margin resorption, subchondral cystic changes, and subsequent joint space widening,1,10,16 all features that were shown in our patient 8 months after the onset of his symptoms. An additional radiographic finding
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Journal of Manipulative and Physiological Therapeutics September 2004
Osteolysis of the Clavicle
seen on initial and subsequent images of our patient was an intra-articular AC joint gas collection. This is a typical finding seen in degenerative joint disease17; however, no reports in the literature have linked this finding to ODC. It is reasonable to assume the intra-articular gas collection seen in the AC joint of our patient most likely represents a concomitant degenerative complication. Continued repetitive stress across the AC joint without intervention may extend the lytic phase of stress-induced osteolysis from 12 to 18 months, resulting in progressive radiolucency of the distal clavicle up to 0.5 to 3.0 cm.10 However, in contrast to posttraumatic ODC, in which extreme bone loss may be seen, tapering of the distal clavicle is seen only very late in the course of stress-induced ODC.9,14 Eventually, the self-limiting nature of the process intervenes, and the lytic phase stabilizes, with gradual changes of healing seen in the reparative phase during a 4to 6-month period.3,10 Reparative changes consist of reconstitution of the distal clavicular cortex with a reduction in subchondral cysts, but the AC joint classically remains permanently widened.3,8,9,11 This, however, is in contrast to radiographic findings in our patient, which showed serial healing and reversal of the lytic process, ultimately resulting in an AC joint of normal dimension. Unfortunately, the radiographic changes stated above may be subtle or absent in the early stages of the lytic phase. Findings on additional imaging modalities such as magnetic resonance imaging (MRI) or radionuclide bone scan may delineate occult pathology of ODC not visualized on plain films or further characterize the extent and severity of osseous and soft tissue involvement in traumatic and stress-induced ODC. The identification of ODC in the absence of plain film findings or a clinical history of trauma is very important in a patient who does not respond to a trial of conservative care, because more aggressive therapy may be indicated for pain control and prevention of associated delayed complications.1 MRI is a useful modality for the delineation of soft tissue injuries of the shoulder and the osteolysis process. MRI findings in ODC include soft tissue swelling and synovial hypertrophy or bone marrow edema seen as a decrease in signal intensity on T1 spin echo images and as isointensity or hyperintensity on T2 spin echo images within the clavicular bone marrow and/or surrounding soft tissues.8,10 Intra-articular effusion may also be present, seen as increased intra-articular signal intensity on T2 spin echo images.4 Short tau inversion recovery (STIR) images (fat saturation) are most sensitive in showing edematous changes within the bone marrow and surrounding soft tissues, seen as markedly increased signal intensity on these images.1,8,10 It is important, however, to remember that findings of increased MRI signal intensity on T2 spin echo and STIR images are not specific for ODC.1 Increased T2 signal intensity of the AC joint is not uncommon on MRI, and in the absence of associated AC joint pain, it is usually of no clinical significance.1 Other abnormalities
that accompany increased T2 signal intensity of the distal clavicle on MRI include AC osteoarthritis (50%) (changes similar to Modic type 1 changes seen in degenerative disk disease), recent trauma, rotator cuff tendinopathy or tear, septic and inflammatory arthritis, and neoplasm.1,10 Additional findings of ODC on MRI include subchondral cysts, capsular distention, and cortical thinning and irregularity, which may correlate with plain film findings.1,8,9 Intravenous gadolinium is rarely used in the evaluation of ODC; however, it does confirm some degree of increased vascularity and inflammation, seen as increased signal intensity at the AC joint on T1 fat-suppressed images.4 Radionuclide bone scintigraphy findings of ODC correlate with pathologic changes of hyperemia and osteoblastic activity of subchondral bone, seen as increased angiographic and blood pool phases, in addition to increased focal distal clavicular uptake in the delayed phase.16 Increased radiotracer uptake is seen most commonly on the clavicular portion of the AC joint; however, approximately 30% of patients also have increased activity in the adjacent acromion.8,15 The nonspecificity of the MRI examination of the AC joint mentioned above must also be kept in mind with regard to the scintigraphic examination, as it also applies to this imaging modality.
Treatment Options Treatment methods for ODC are generally driven by symptomatology and disease stage. However, controversy does exist on the course of the disease, with some authors concluding that insufficient treatment predisposes and exaggerates the osteolytic process, whereas others believe the eventual severity of bony damage is predetermined and directly related to the severity of the inciting event.3,11 Most do agree, however, that the natural course of the disease process is not that predictable and that determination of the severity of future clavicular involvement, even with early intervention, is ultimately impossible.10 Early intervention generally will not suppress early manifestations but may result in decreased bone loss and an earlier cessation of osteolysis and clinical symptoms.10,11 Conservative treatment options should be used as long as the patient will comply, with consideration of the patient’s symptoms and functional status. Patients have been treated successfully with conservative methods by eliminating provoking activities, immobilizing the extremity, and using physiotherapeutics.3,15 Corticosteroid injections and oral anti-inflammatory agents have been used with limited success.8,10,15 For those patients who fail conservative care or athletes who refuse to eliminate provoking activities, surgical resection is the procedure of choice. Currently, open resection and arthroscopic techniques are employed in the surgical management of ODC. Open distal clavicular excision was first described in 1902 and popularized in
Gajeski and Kettner 480.e5 Osteolysis of the Clavicle
Journal of Manipulative and Physiological Therapeutics Volume 27, Number 7
the early 1940s by Gurd and Mumford for symptomatic traumatic AC joint pathology.15,18 The open resection technique removes the pathologic articular surfaces, creating a wide enough margin for removal of the osteolytic process in its entirety, and prevents AC abutment during abduction.8 Many authors have since reported satisfactory results with the procedure for both traumatic and nontraumatic painful entities of the AC joint,10,15,18,19 resulting in significant pain relief within 4 to 8 weeks after surgery in most patients.8,18,20 However, not all patients will be able to return to their former athletic or occupational status after surgery due to ongoing functional impairment and limitation of shoulder motion and strength. Outcomes of less invasive arthroscopic approaches to distal clavicular excision have been shown to surpass open clavicular resection in a variety of studies.18,20 Open resection invades the deltotrapezial fascia of the shoulder, weakening the extremity and potentiating postoperative instability.10 The arthroscopic approach differs from the standard open technique in that both the acromion and the clavicle are resected via an indirect bursal or direct superior approach and spares the deltotrapezial fascia.20 Arthroscopic methods have shown a more rapid return to daily living and work activities versus the open approach, with an overall equivalent or superior relief of symptoms and a reduction in postoperative complications.15,20
CONCLUSIONS Osteolysis of the distal clavicle has been described as progressive resorption of the distal clavicle after acute and chronic, stress-induced shoulder injury. The familiarity of clinicians with ODC is of utmost importance, as the entity often presents insidiously and may mimic other shoulder pathology. The history of trauma and positive radiographic evidence clinch the diagnosis, yet specialized imaging, including MRI and bone scintigraphy, may be necessary for early diagnosis and initiation of therapy. Classically, the pathologic process is ultimately self-limiting with or without early therapy and results in a widened AC joint on radiographs along with reduced function of the extremity. This case report highlighted and showed a patient whose radiographs, after aggressive although conservative therapy, showed progressive, serial distal clavicular healing and normalization of joint space dimension. Surgical treatment may be necessary for patients who do not respond to conservative care and/or refuse to modify provocative activities.
REFERENCES 1. Fiorella D, Helms CA, Speer KP. Increased T2 signal intensity in the distal clavicle: incidence and clinical implications. Skeletal Radiol 2000;29:697-702. 2. Yochum TR, Rowe LJ. Measurements in skeletal radiology. In: Yochum TR, Rowe LJ, editors. Essentials in skeletal radiology. Baltimore7 Williams and Wilkins; 1996 p. 185. 3. Reber P, Patel AG, Hess R, Noesberger B. Post-traumatic osteolysis of the distal clavicle. Arch Orthop Trauma Surg 1996;115:120-2. 4. de la Puente R, Boutin RD, Theodorou DJ, Hooper A, Schweitzer M, Resnick D. Post-traumatic and stress-induced osteolysis of the distal clavicle: MR imaging findings in 17 patients. Skeletal Radiol 1999;28:202-8. 5. Murphy OB, Bellamy R, Wheeler W, Brower TD. Posttraumatic osteolysis of the distal clavicle. Clin Orthop 1975; 109:108-14. 6. Hawkins BJ, Covey DC, Thiel BG. Distal clavicle osteolysis unrelated to trauma, overuse, or metabolic disease. Clin Orthop 2000;370:208-11. 7. Brahee DD, Kettner NW. Osteolysis of the distal clavicle: a review. Top Diagn Radiol Adv Imaging 1999;Fall:10-4. 8. Clarke HD, McCann PD. Acromioclavicular joint injuries. Orthop Clin North Am 2000;31:177-87. 9. Mestan MA, Bassano JM. Posttraumatic osteolysis of the distal clavicle: analysis of 7 cases and a review of the literature. J Manipulative Physiol Ther 2001;24:356-61. 10. Levine AH, Pais MJ, Schwartz EE. Posttraumatic osteolysis of the distal clavicle with emphasis on early radiographic changes. Am J Roentgenol 1976;127:781-4. 11. Brunet ME, Reynolds MC, Cook SD, Brown TW. Atraumatic osteolysis of the distal clavicle: histologic evidence of synovial pathogenesis. A case report. Orthopedics 1986;9:557-9. 12. Reeder MM. Bone, joints, and soft tissues. In: Reeder MM. Gamuts in radiology. New York7 Springer-Verlag Inc.; 1993. p. 269. 13. Brahee D, Osborne CA, Burke J, Kettner N, Rehmel D, Gajeski B. The prevalence of osteolysis of the distal clavicle in recreational weight trainers. J Sports Chiropr Rehabil 2001;15: 71-9. 14. Patten RM. Atraumatic osteolysis of the distal clavicle: MR findings. J Comput Assist Tomogr 1995;19:92-5. 15. Cahill BR. Atraumatic osteolysis of the distal clavicle. A review. Sports Med 1992;13:214-22. 16. Sopov V, Fuchs D, Bar-Meir E, Groshar D. Stress-induced osteolysis of distal clavicle: imaging patterns and treatment using CT-guided injection. Eur Radiol 2001;11:270-2. 17. Resnick D. Diagnosis of bone and joint disorders. 4th ed. Philadelphia: W.B. Saunders Company; 2002. p. 1327, 1350, 1408. 18. Petchell JF, Sonnabend DH, Hughes JS. Distal clavicular excision: a detailed functional assessment. Aust N Z J Surg 1995;65:262-6. 19. Scavenius M, Iversen BF. Nontraumatic clavicular osteolysis in weight lifters. Am J Sports Med 1992;20:463-7. 20. Henry MH, Liu SH, Loffredo AJ. Arthroscopic management of the acromioclavicular joint disorder. A review. Clin Orthop 1995;316:276-83.