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Local arthroscopic bone grafting of a juxta-articular glenoid bone cyst
Case Report
Local Arthroscopic Bone Grafting of a Juxta-articular Glenoid Bone Cyst Seok-Beom
L e e , M . D . , a n d D o u g l a s T. H a r r y m a n II, M . D .
Summary: This report describes a rare, juxta-articular bone cyst of the posterior glenoid that developed after a fracture of the glenoid in a 38-year-old male. The patient had persistent pain, popping and stiffness of his right shoulder for 3 years, and failed to improve after a nonoperative rehabilitation program. At arthroscopy, the senior author transported an autogenous bone graft from the bare area of the humeral head to fill the glenoid cyst arthroscopically. At second-look arthroscopy approximately 1 year after the index procedure, the bone graft had consolidated within the original cystic defect and the surface was covered with fibrocartilage. The graft harvest site posteriorly on the humeral head had healed with a small amount of scar tissue at the articular margin. Comfortable motion and function were restored. Key Words: Glenoid juxta-articular cyst--Arthroscopic bone graft.
Juxta-articular bone cyst is typically defined as a benign and often multiloculated intraosseous ganglion lesion composed of fibrous tissue, septae, and extensive mucoid changes, located adjacent to the subchondral bone of a joint. Although the pathogenesis of these lesions is not clear, Schajowicz et al. 1 proposed two types of juxta-articular bone cysts: one is said to originate by penetration of an extraosseous ganglion into the underlying bone, and the other is simply idiopathic. We believe that the juxta-articular bone cyst in our patient's shoulder developed after a traumatic injury with a posterior glenoid fracture that originally extended into the joint. The purpose of this report is to present an arthroscopic method of managing a juxta-articular bone cyst below the articular surface, subsequent to a fracture of
A
From the Department of Orthopaedics, University of Washington, Seattle, Washington, U.S.A. Address correspondence and reprint requests to Douglas T. Harryman 11,M.D., Department of Orthopaedics, Universityof Washington, Box 356500, 1959 NE Pacific, Seattle, WA 98195, U.S.A. © 1997 by the Arthroscopy Association of North America 0749-8063/97/1304-162353.00/0
502
the posterior glenoid rim. We describe the arthroscopic technique used to prepare and fill the cystic glenoid defect with autogenous bone harvested from the bare area of the humeral head.
CASE REPORT A 38-year-old right handed carpenter sustained an injury 3 years before presentation, when a heavy bundle of shingles fell off a roof and impacted the lateral aspect of his fight shoulder. Afterwards, he had persistent pain, popping, and restricted use of his right shoulder. His symptoms did not respond to a stretching and strengthening program. Pain was accentuated with lying on the affected side. Painful stiffness limited his ability to wash the back of the opposite shoulder and to reach up his back. On examination at the University of Washington, his range of cross-body adduction (10 cm greater span between acromion and antecubital fossa), and internal rotation in abduction (40 ° decrement relative to the contralateral shoulder), were significantly limited. The range of forward elevation and external rotation were
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 13, No 4 (August), 1997: pp 502-506
BONE GRAFT OF GLENOID JUXTA-ARTICULAR CYST
FIG 1. A plain axillary radiograph showing a malunited fracture (arrowheads) of the posterior third of the glenoid with a slight stepoff disrupting the normal concavity.
symmetrical. Crepitance was easily detected on palpation with humeral rotation and elevation. On drawer laxity testing, anterior translation was equal bilaterally. Posterior translation was not possible on the affected side but contralaterally, a normal 50% glide was easily produced on manual manipulation. Stability tests were unremarkable and strength was normal throughout. The plain axillary radiograph showed a malunited fracture of the posterior third of the glenoid with a slight step-off disrupting the normal concavity (Fig l ).
FIG 2. A computed tomographicarthrogramshowing a large posterior subchondral cyst adjacent to a malunited glenoid deformity consistent with a healed fracture.
503
FIG 3. An arthroscopic view showing an obvious articular cartilage defect in the posterior third of the glenoid (5 x 7 mm) and a small opening communicating with the cyst through the exposed subchondral bone. A flap of cartilage partially covered the lesion.
A computed tomographic arthrogram revealed a large posterior subchondral cyst adjacent to a malunited glenoid deformity consistent with a healed impaction fracture (Fig 2). After considering the history and radiographic findings, our clinical impression was that the patient had sustained a posterior glenoid fracture at the time of injury that healed and subsequently developed a subchondral cyst. The patient consented to a right shoulder arthroscopic examination to evaluate and treat the articular surface and posterior labrum as well as to release the posterior capsule. After administration of regional interscalene anesthesia to the affected extremity, the patient was placed in a beach chair position. Laxity and stability tests were performed that confirmed our preoperative clinical examination. On arthroscopic examination, there was an obvious articular cartilage defect in the posterior third of the glenoid which measured approximately 5 x 7 mm. A cartilage flap partially covered the lesion, which was located just anterior to the posterior glenoid labrum (Fig 3). A small opening through the exposed subchondral bone surface was seen that communicated with the cyst. The posterior capsule was synovitic, thickened, and contracted. An osteocartilagenous fragment was extracted from the inferior recess where it was loose in the joint. A 4 - m m ball burr was used to increase the size of the opening, which entered into the cyst below the subchondral bone. After the cavity was debrided to expose bleeding cancellous bone,
504
S.-B. LEE AND D. T. H A R R Y M A N H
FIG 4. A view of arthroscopic harvesting of autologous local bone graft from the posterior bare area of the humeral head (H). Visualization of the bare area was improved by using a 70 ° arthroscope inserted through the anterior portal.
plugs of bone graft were extracted from the posterior bare area of the humeral head (Fig 4). The cancellous bone plugs were compacted in the cavity to fill the defect up to the cartilage surface (Fig 5). Visualization of the humeral head bare area and the posterior aspect of the glenoid during extraction and grafting of bone
was improved by using a 70 ° arthroscope inserted through the anterior portal. The posterior capsule was also released from superior to inferior leaving the labral rim intact. Continuous passive motion and active assisted full range of motion was begun immediately after surgery. The patient noticed improvement in range immediately after the operation. Within 3 weeks, cross-body adduction and internal rotation of right shoulder became nearly symmetric with the opposite side. At followup examination, his glenohumeral motion was quite smooth except for minimal crepitance at the extremes of range. Strength and stability remained normal. Approximately 1 year after the procedure, the patient underwent a second look arthroscopy before engaging in strenuous activity to insure that the joint surface had been restored. On arthroscopic examination, the posterior capsule had reformed (Fig 6). The bone graft donor site in the bare area of the humeral head had healed over with minimal scarring (Fig 7). The grafted area on the posterior glenoid articular surface was now approximately 3 X 4 mm. The edges of the defect were quite smooth. On further probing of the lesion, we determined that the subchondral surface had filled in completely and a layer of fibrocartilage covered the bony surface (Fig 8). Postoperatively, the patient was placed on an aggressive range of motion and strengthening exercise program. On examination 1 month after the second-look
FIG 5. (A) Arthroscopic cancellous bone graft being packed into the cavity to fill the glenoid cyst. (B) Arthroscopic view immediately after the glenoid cyst was filled with cancellous bone graft (BG) to the cartilage surface level.
BONE GRAFT OF GLENOID JUXTA-ARTICULAR CYST
FIG 6.
Second-look arthroscopic examination 1 year after posterior capsular release. The posterior capsule (arrowhead) had completely reformed (H, humeral head; L, labrum.).
arthroscopy, range of motion was nearly full. Bilateral forward elevation was 170 °, external rotation at the side 70 °, and in the abduction 90 °. Internal rotation in an abduction was 50 ° on the operated shoulder and 70 ° on the opposite side. Internal rotation up the back was to T12 as compared with T4. Cross-body adduction
505
FIG 8. Second-look arthroscopic view showing the grafted area (3 x 4 mm) on the posterior glenoid. The edges of the defect were quite smooth. On probing the base of the lesion, the restored subchondral surface was covered with fibrocartilage.
was 12 cm bilaterally. Passive range o f motion revealed smooth glenohumeral motion except in the position of adduction and internal rotation where a light grind and pain could be provoked. W e recommended avoiding this position and continuing rehabilitation exercises. DISCUSSION
FIG 7. Second-look arthroscopic view of the bone graft donor site in the bare area of the humeral head. The peripheral fibrocartilage (*) adjacent to the articular surface was debrided after this picture was taken.
Since the first report by Fisk z of intraosseous penetration of a periosteal ganglion-like structure with subsequent formation of a cystic defect in the subjacent bone, others 3'4 have described similar cases using various terminology. The accepted World Health Organization classification of these benign bone t u m o r - l i k e lesions 5 was described by Schajowicz et al I, who applied the terminology "juxta-articular bone cyst (intraosseous ganglion)" and further defined them as benign cystic and often multiloculated lesions made up of fibrous tissue with extensive mucoid changes located in the subchondral bone adjacent to a joint. The etiology and pathogenesis of these lesions is not clear, although many theories have been proposed. Schajowicz et all described two fundamental types of intraosseous ganglia: one being idiopathic and the other originating by penetration through the cortex into the underlying bone. The idiopathic type seems to arise de novo within bone, secondary to intramedullary
506
S.-B. L E E A N D D. T. H A R R Y M A N H
metaplasia and a proliferative process leading to the formarion of fibroblast and mucin-secreting cells, which cause pressure atrophy of the bone trabeculae. Fairbank and Lloyd6 reported the most striking examples of the penetrating type, namely, erosion of the head of tibia by meniscal cysts. Fisk 2 reported another example of the penetrating type, where a simple ganglion induced a cupshaped depression in the medial malleolus. Intraosseous ganglia have been reported in the long tubular bones, carpal scaphoid, tarsal navicular, talus, and calcaneous.l'2'7'8 Only a few cases ofjuxta-articular bone cysts have been mentioned about the shoulder. Schajowicz et al. 1 reported an idiopathic scapular lesion, but did not describe its location. Freundlich and Pascal 9 reported an idiopathic juxta-articular bone cyst in the glenoid, which was curetted with an open posterior approach. Yamato et al. m described a case of an idiopathic asymptomatic intraosseous ganglion of the scapula that was excised and curetted. Formation of a juxta-articular bone cyst after an intra-articular fracture has not been described previously. The present case is of particular interest because the cyst communicated with the joint, similar to periarticular soft tissue ganglia. We believe this cyst developed after a malunion of an intra-articular fracture and recognize that without a pathological diagnosis we remain unable to confirm whether this cavity truly represented an intraosseous ganglia. Excision and curettage with or without bone grafting of the cyst has been the treatment used for the majority of reported c a s e s . 1-4'6m Local transport of bone graft from the humeral head bare area to the defect was simple and successful. We believe that this arthroscopic method of treating an articular cystic cavity with a cancellous bone graft can be applied without concern for potential displacement of the compacted bone since
the humeral head applies constant compression to the glenoid concavity. Damaged hyaline cartilage has a very limited capacity for regeneration, particularly with large traumatic lesions. H In this case, the bone appeared to have solidly filled the cyst, restoring the subchondral bone surface at the second arthroscopic examination. The surface was covered with a thin layer of apparent fibrocartilage that we hope will eventually fill and restore a smooth articular surface. Meanwhile, stiffness of the involved shoulder was significantly diminished by arthroscopic posterior capsular release and function was improved. The early results are promising. We conclude that this case is a successful example of arthroscopic preparation and bone grafting of a post-traumatic juxta-articular bone cyst of the glenoid.
REFERENCES 1. Schajowicz F, Sainz MC, Slullitel JA. Juxta-articular bone cysts (intraosseous ganglia). J Bone Joint Surg Br 1979;61:107-116. 2. Fisk GR. Bone concavity caused by a ganglion. J Bone Joint Surg Br 1949; 31:220-221. 3. Kambolis C, Bullough PG, Jaffe HL. Ganglionic cystic defects of bone. J Bone Joint Surg Am 1973;55:496-505. 4. Woods CG. Subchondral bone cysts. J Bone Joint Surg Br 1961 ; 43:758-766. 5. Schajowicz F, Ackerman LV, Sissons HA. Histological typing of bone tumor. International Histological Classification of Tu-
mours, No. 6. Geneva: World Health Organization, 1972. 6. Fairbank HAT, Lloyd EI. Cysts of the external cartilage of the knee with erosion of the head of the tibia. Br J Surg 1934;22: 115-118. 7. Crabbe WA. Intraosseous ganglia of bone. Br J Surg 1966;53: 5-17. 8. Murff R, Ashry HR. Intraosseous ganglia of the foot. J Foot Ankle Surg 1994;33:396-401. 9. Freundlich BD, Pascal P. Juxta-articularbone cyst of the glenoid. Clin Orthop 1984;188:196-198. 10. Yamato M, Saotome K, Tamai K, Yamaguchi T. Case report 783. Skeletal Radiol 1993;22:227-228. 11. Sevitt S. Healing of traumatic lesions of articular surface. In: Bone repair and fracture healing in man. Edinburgh: Churchill Livingstone, 1981; 1-24.
Local Arthroscopic Bone Grafting of a Juxta-articular Glenoid Bone Cyst Seok-Beom
L e e , M . D . , a n d D o u g l a s T. H a r r y m a n II, M . D .
Summary: This report describes a rare, juxta-articular bone cyst of the posterior glenoid that developed after a fracture of the glenoid in a 38-year-old male. The patient had persistent pain, popping and stiffness of his right shoulder for 3 years, and failed to improve after a nonoperative rehabilitation program. At arthroscopy, the senior author transported an autogenous bone graft from the bare area of the humeral head to fill the glenoid cyst arthroscopically. At second-look arthroscopy approximately 1 year after the index procedure, the bone graft had consolidated within the original cystic defect and the surface was covered with fibrocartilage. The graft harvest site posteriorly on the humeral head had healed with a small amount of scar tissue at the articular margin. Comfortable motion and function were restored. Key Words: Glenoid juxta-articular cyst--Arthroscopic bone graft.
Juxta-articular bone cyst is typically defined as a benign and often multiloculated intraosseous ganglion lesion composed of fibrous tissue, septae, and extensive mucoid changes, located adjacent to the subchondral bone of a joint. Although the pathogenesis of these lesions is not clear, Schajowicz et al. 1 proposed two types of juxta-articular bone cysts: one is said to originate by penetration of an extraosseous ganglion into the underlying bone, and the other is simply idiopathic. We believe that the juxta-articular bone cyst in our patient's shoulder developed after a traumatic injury with a posterior glenoid fracture that originally extended into the joint. The purpose of this report is to present an arthroscopic method of managing a juxta-articular bone cyst below the articular surface, subsequent to a fracture of
A
From the Department of Orthopaedics, University of Washington, Seattle, Washington, U.S.A. Address correspondence and reprint requests to Douglas T. Harryman 11,M.D., Department of Orthopaedics, Universityof Washington, Box 356500, 1959 NE Pacific, Seattle, WA 98195, U.S.A. © 1997 by the Arthroscopy Association of North America 0749-8063/97/1304-162353.00/0
502
the posterior glenoid rim. We describe the arthroscopic technique used to prepare and fill the cystic glenoid defect with autogenous bone harvested from the bare area of the humeral head.
CASE REPORT A 38-year-old right handed carpenter sustained an injury 3 years before presentation, when a heavy bundle of shingles fell off a roof and impacted the lateral aspect of his fight shoulder. Afterwards, he had persistent pain, popping, and restricted use of his right shoulder. His symptoms did not respond to a stretching and strengthening program. Pain was accentuated with lying on the affected side. Painful stiffness limited his ability to wash the back of the opposite shoulder and to reach up his back. On examination at the University of Washington, his range of cross-body adduction (10 cm greater span between acromion and antecubital fossa), and internal rotation in abduction (40 ° decrement relative to the contralateral shoulder), were significantly limited. The range of forward elevation and external rotation were
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 13, No 4 (August), 1997: pp 502-506
BONE GRAFT OF GLENOID JUXTA-ARTICULAR CYST
FIG 1. A plain axillary radiograph showing a malunited fracture (arrowheads) of the posterior third of the glenoid with a slight stepoff disrupting the normal concavity.
symmetrical. Crepitance was easily detected on palpation with humeral rotation and elevation. On drawer laxity testing, anterior translation was equal bilaterally. Posterior translation was not possible on the affected side but contralaterally, a normal 50% glide was easily produced on manual manipulation. Stability tests were unremarkable and strength was normal throughout. The plain axillary radiograph showed a malunited fracture of the posterior third of the glenoid with a slight step-off disrupting the normal concavity (Fig l ).
FIG 2. A computed tomographicarthrogramshowing a large posterior subchondral cyst adjacent to a malunited glenoid deformity consistent with a healed fracture.
503
FIG 3. An arthroscopic view showing an obvious articular cartilage defect in the posterior third of the glenoid (5 x 7 mm) and a small opening communicating with the cyst through the exposed subchondral bone. A flap of cartilage partially covered the lesion.
A computed tomographic arthrogram revealed a large posterior subchondral cyst adjacent to a malunited glenoid deformity consistent with a healed impaction fracture (Fig 2). After considering the history and radiographic findings, our clinical impression was that the patient had sustained a posterior glenoid fracture at the time of injury that healed and subsequently developed a subchondral cyst. The patient consented to a right shoulder arthroscopic examination to evaluate and treat the articular surface and posterior labrum as well as to release the posterior capsule. After administration of regional interscalene anesthesia to the affected extremity, the patient was placed in a beach chair position. Laxity and stability tests were performed that confirmed our preoperative clinical examination. On arthroscopic examination, there was an obvious articular cartilage defect in the posterior third of the glenoid which measured approximately 5 x 7 mm. A cartilage flap partially covered the lesion, which was located just anterior to the posterior glenoid labrum (Fig 3). A small opening through the exposed subchondral bone surface was seen that communicated with the cyst. The posterior capsule was synovitic, thickened, and contracted. An osteocartilagenous fragment was extracted from the inferior recess where it was loose in the joint. A 4 - m m ball burr was used to increase the size of the opening, which entered into the cyst below the subchondral bone. After the cavity was debrided to expose bleeding cancellous bone,
504
S.-B. LEE AND D. T. H A R R Y M A N H
FIG 4. A view of arthroscopic harvesting of autologous local bone graft from the posterior bare area of the humeral head (H). Visualization of the bare area was improved by using a 70 ° arthroscope inserted through the anterior portal.
plugs of bone graft were extracted from the posterior bare area of the humeral head (Fig 4). The cancellous bone plugs were compacted in the cavity to fill the defect up to the cartilage surface (Fig 5). Visualization of the humeral head bare area and the posterior aspect of the glenoid during extraction and grafting of bone
was improved by using a 70 ° arthroscope inserted through the anterior portal. The posterior capsule was also released from superior to inferior leaving the labral rim intact. Continuous passive motion and active assisted full range of motion was begun immediately after surgery. The patient noticed improvement in range immediately after the operation. Within 3 weeks, cross-body adduction and internal rotation of right shoulder became nearly symmetric with the opposite side. At followup examination, his glenohumeral motion was quite smooth except for minimal crepitance at the extremes of range. Strength and stability remained normal. Approximately 1 year after the procedure, the patient underwent a second look arthroscopy before engaging in strenuous activity to insure that the joint surface had been restored. On arthroscopic examination, the posterior capsule had reformed (Fig 6). The bone graft donor site in the bare area of the humeral head had healed over with minimal scarring (Fig 7). The grafted area on the posterior glenoid articular surface was now approximately 3 X 4 mm. The edges of the defect were quite smooth. On further probing of the lesion, we determined that the subchondral surface had filled in completely and a layer of fibrocartilage covered the bony surface (Fig 8). Postoperatively, the patient was placed on an aggressive range of motion and strengthening exercise program. On examination 1 month after the second-look
FIG 5. (A) Arthroscopic cancellous bone graft being packed into the cavity to fill the glenoid cyst. (B) Arthroscopic view immediately after the glenoid cyst was filled with cancellous bone graft (BG) to the cartilage surface level.
BONE GRAFT OF GLENOID JUXTA-ARTICULAR CYST
FIG 6.
Second-look arthroscopic examination 1 year after posterior capsular release. The posterior capsule (arrowhead) had completely reformed (H, humeral head; L, labrum.).
arthroscopy, range of motion was nearly full. Bilateral forward elevation was 170 °, external rotation at the side 70 °, and in the abduction 90 °. Internal rotation in an abduction was 50 ° on the operated shoulder and 70 ° on the opposite side. Internal rotation up the back was to T12 as compared with T4. Cross-body adduction
505
FIG 8. Second-look arthroscopic view showing the grafted area (3 x 4 mm) on the posterior glenoid. The edges of the defect were quite smooth. On probing the base of the lesion, the restored subchondral surface was covered with fibrocartilage.
was 12 cm bilaterally. Passive range o f motion revealed smooth glenohumeral motion except in the position of adduction and internal rotation where a light grind and pain could be provoked. W e recommended avoiding this position and continuing rehabilitation exercises. DISCUSSION
FIG 7. Second-look arthroscopic view of the bone graft donor site in the bare area of the humeral head. The peripheral fibrocartilage (*) adjacent to the articular surface was debrided after this picture was taken.
Since the first report by Fisk z of intraosseous penetration of a periosteal ganglion-like structure with subsequent formation of a cystic defect in the subjacent bone, others 3'4 have described similar cases using various terminology. The accepted World Health Organization classification of these benign bone t u m o r - l i k e lesions 5 was described by Schajowicz et al I, who applied the terminology "juxta-articular bone cyst (intraosseous ganglion)" and further defined them as benign cystic and often multiloculated lesions made up of fibrous tissue with extensive mucoid changes located in the subchondral bone adjacent to a joint. The etiology and pathogenesis of these lesions is not clear, although many theories have been proposed. Schajowicz et all described two fundamental types of intraosseous ganglia: one being idiopathic and the other originating by penetration through the cortex into the underlying bone. The idiopathic type seems to arise de novo within bone, secondary to intramedullary
506
S.-B. L E E A N D D. T. H A R R Y M A N H
metaplasia and a proliferative process leading to the formarion of fibroblast and mucin-secreting cells, which cause pressure atrophy of the bone trabeculae. Fairbank and Lloyd6 reported the most striking examples of the penetrating type, namely, erosion of the head of tibia by meniscal cysts. Fisk 2 reported another example of the penetrating type, where a simple ganglion induced a cupshaped depression in the medial malleolus. Intraosseous ganglia have been reported in the long tubular bones, carpal scaphoid, tarsal navicular, talus, and calcaneous.l'2'7'8 Only a few cases ofjuxta-articular bone cysts have been mentioned about the shoulder. Schajowicz et al. 1 reported an idiopathic scapular lesion, but did not describe its location. Freundlich and Pascal 9 reported an idiopathic juxta-articular bone cyst in the glenoid, which was curetted with an open posterior approach. Yamato et al. m described a case of an idiopathic asymptomatic intraosseous ganglion of the scapula that was excised and curetted. Formation of a juxta-articular bone cyst after an intra-articular fracture has not been described previously. The present case is of particular interest because the cyst communicated with the joint, similar to periarticular soft tissue ganglia. We believe this cyst developed after a malunion of an intra-articular fracture and recognize that without a pathological diagnosis we remain unable to confirm whether this cavity truly represented an intraosseous ganglia. Excision and curettage with or without bone grafting of the cyst has been the treatment used for the majority of reported c a s e s . 1-4'6m Local transport of bone graft from the humeral head bare area to the defect was simple and successful. We believe that this arthroscopic method of treating an articular cystic cavity with a cancellous bone graft can be applied without concern for potential displacement of the compacted bone since
the humeral head applies constant compression to the glenoid concavity. Damaged hyaline cartilage has a very limited capacity for regeneration, particularly with large traumatic lesions. H In this case, the bone appeared to have solidly filled the cyst, restoring the subchondral bone surface at the second arthroscopic examination. The surface was covered with a thin layer of apparent fibrocartilage that we hope will eventually fill and restore a smooth articular surface. Meanwhile, stiffness of the involved shoulder was significantly diminished by arthroscopic posterior capsular release and function was improved. The early results are promising. We conclude that this case is a successful example of arthroscopic preparation and bone grafting of a post-traumatic juxta-articular bone cyst of the glenoid.
REFERENCES 1. Schajowicz F, Sainz MC, Slullitel JA. Juxta-articular bone cysts (intraosseous ganglia). J Bone Joint Surg Br 1979;61:107-116. 2. Fisk GR. Bone concavity caused by a ganglion. J Bone Joint Surg Br 1949; 31:220-221. 3. Kambolis C, Bullough PG, Jaffe HL. Ganglionic cystic defects of bone. J Bone Joint Surg Am 1973;55:496-505. 4. Woods CG. Subchondral bone cysts. J Bone Joint Surg Br 1961 ; 43:758-766. 5. Schajowicz F, Ackerman LV, Sissons HA. Histological typing of bone tumor. International Histological Classification of Tu-
mours, No. 6. Geneva: World Health Organization, 1972. 6. Fairbank HAT, Lloyd EI. Cysts of the external cartilage of the knee with erosion of the head of the tibia. Br J Surg 1934;22: 115-118. 7. Crabbe WA. Intraosseous ganglia of bone. Br J Surg 1966;53: 5-17. 8. Murff R, Ashry HR. Intraosseous ganglia of the foot. J Foot Ankle Surg 1994;33:396-401. 9. Freundlich BD, Pascal P. Juxta-articularbone cyst of the glenoid. Clin Orthop 1984;188:196-198. 10. Yamato M, Saotome K, Tamai K, Yamaguchi T. Case report 783. Skeletal Radiol 1993;22:227-228. 11. Sevitt S. Healing of traumatic lesions of articular surface. In: Bone repair and fracture healing in man. Edinburgh: Churchill Livingstone, 1981; 1-24.