Radiographic Diagnosis of Quadriceps Tendon Rupture
1
Diagnostic Radiology
Arthur Newberg, M.D., and Lee Wales, M.D.
Traumatic rupture of the quadriceps tendon is anuncommon kneeinjury whichoccurs in the elderly, and/or the obese, andin thosewith underlying systemicdisease. Tenpatients with 13 ruptures havebeen seen at the Massachusetts General Hospital in the last nine years. Clinically, the patientis unable to actively extend the knee. Onthe lateralview of theknee there is loss of normal quadriceps outline anda soft-tissue masswith calcificationrepresenting the retracted quadriceps tendon. Mostpatients havea hemarthrosis. Theclinical diagnosis is often overlooked, andthe radiologist could be the first to suggest the diagnosis. Knee, wounds and injuries. (Knee, other injury, 4(5).4859) • (Knee, other calcification, 4(5).819). (Knee, traumatic hemarthrosis, 4(5) .492). Tendons
INDEX TERMS:
Radiology 125:367-371, November 1977 RAUMATIC RUPTURE of the quadriceps tendon is an uncommon knee injury which causes disruption of the extensor mechanism of the knee. Patellar fractures, patellar tendon rupture, and avulsion of the tibial tubercle constitute the other causes of disruption of the knee ex tensor mechanism. The mechanism of injury is a sudden violent contraction of the quadriceps against the body weight with the knee flexed, as the patient tries to prevent a fall (1). The actual moment of tearing occurs with the patella firmly held against the anterior aspect of the femur buttressed by the medial and lateral condyles, and the muscle exerting maximum contraction (Fig. 1). The tear occurs first in the central portion of the tendon anteriorly, with the medial and lateral fibers subsequently tearing depending on the duration and amount of the force (2). The tear usually occurs 1-2 cm above the patella, but disruption may occur at the musculotendinous junction, in the muscle belly, or at the tendinous insertion into bone. A small fragment of bone may be avulsed from the patella (3). Two patients with traumatic rupture of the quadriceps tendon were recently seen at our institution, and this prompted a review of our previous experience.
T
Fig. 1. Schematic representation of quadriceps tendon rupture. There is proximal retraction of the torntendon resulting in a poorlydefined soft-tissue mass. The adjacent suprapatellar bursa usually contains hemarthrosis secondary to tearof thejoint capsule.
MATERIALS AND METHODS
Ten patients with 13 ruptures of the quadriceps tendon were seen in the last nine years at the Massachusetts General Hospital (TABLE I). Three had bilateral ruptures, a not uncommon finding (4-12). The rupture did not occur simultaneously in 2 of the 3 bilateral ruptures. There were 9 men and 1 woman. The average age was 65 with a range from 43 to 87. Two patients were obese, 2 had mild adult onset of diabetes mellitus, 1 had an elevated serum uric acid, and 1 chronic renal failure (bilateral ruptures). The remaining patients had no underlying medical problems. Radiographs of all but one of the ruptures were available for review and all had surgical confirmation.
All of the patients suffered a fall and sought medical attention within 48 hours following injury. One patient's evaluation was delayed. The most common initial clinical diagnosis was internal derangement of the knee with subsequent orthopedic evaluation, eliciting the diagnosis of quadriceps rupture. All of the patients had anteroposterior and lateral radiographs of the knee, and in none did the radiologist suggest the correct diagnosis. Surgery revealed complete rupture of the quadriceps tendon in 7 cases and incomplete tears in 4 cases. Hemarthrosis was noted in the majority with an associated tear in the capsule of the knee. Detailed surgical reports were
1 From theDepartments of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass. 02114. Accepted for publication in April 1977. shan
367
368
ARTHUR NEWBERG AND LEE WALES
November 1977
Fig. 2. Radiographs (A) and xerograms (B) of both knees illustrating suprapatellar soft-tissue mass, punctate calcifications, disruption of normal quadriceps tendon and obliteration of normal soft-tissue planes .
not available for 2 ruptures. An illustrative case report follows. CASE REPORT A 43-year-old woman with a history of chronic renal failure fell two weeks prior to admission and complained of left knee pain thereafter,
but was able to walk. Four days prior to admission, she fell onto her right knee and thereafter could not walk. Progressive pain and disability led her to seek medical attention. On physical examination, she had bilateral knee effusions, bilateral suprapatellar tenderness, no active right extension, and poor active left extension. Radiographic and xerographic examinations were performed (Fig. 2). Direct surgical repair of the right knee revealed complete rupture of the tendon, calcification of the tendon, and hematoma. She regained full use of the right knee, but
369
QUADRICEPS TENDON RUPTURE
Vo l. 125
Diagnostic Radiology
Fig. 3. Right knee . Note fine calcifications, effusion, and loss of normal fascial planes.
continued weakness and pain of the left knee led to repair four months later. Surgical findings revealed extensive fibrosis in the area of the partial rupture, and a primary anastomosis was performed.
Fig. 4. Left knee demonstrating discrete dense calcification within the retracted quadriceps tendon (open arrow) . There is an effusion present with obliteration of the normal quadriceps tendon outline.
RADIOGRAPHIC FINDINGS
Pertinent radiographic findings were noted in lateral projection and were best seen with soft-tissue technique or xerography. Significant findings were either a small cluster of fine irregular calcifications (Fig. 3), or more discrete coarse calcific densities (Fig. 4) in the suprapatellar region in a poorly defined soft-tissue mass repre-
senting the retracted proximal portion of the disrupted tendon. This calcification was noted in 8/13 knees and was a more frequent finding in cases of complete rupture. The usually well-defined density of the quadriceps tendon was absent in 8/13 knees (Fig. 4). A suprapatellar effusion was identified in 9/13 knees. Minimal degenerative spurring was noted about the patella in 5/13 knees.
TABLE I: SUMMARY OF TEN PATIENTS WITHTRAUMATIC QUADRICEPS TENDON RUPTURE
PATIENT
AGE SEX
HISTOR Y
KNEE
MM PD RS
52 M 67 M 71 M
Fall Fall Fall
R
GP
Fall Fall
R
FS
52 M 64M
DC
43 F
Fall
R
L R
L L
L HP
58M
Fall
R
PH PM AC
78 M 87M 72M
Fall Fall Fall
R
L L
R
EFFUSION
OBUTERATlON OF QUADRICEPS TENDON
SUPRAPATELLAR SOFT-TISSUE MASS
No Yes Yes No No Yes
Ye s Yes Yes Yes Yes Yes
Yes Yes Yes Yes Ye s Yes
Ye s Yes Yes Ye s Yes Ye s
Yes Yes Films not available Yes No Yes Yes
No Yes
Yes Yes
Yes Yes
No Yes Yes Yes
No Yes
No Yes Yes Yes
CALCIFICATION
? Yes
SURGICAL FINDINGS Complete ruptur e Complete rupt ure Complete rup ture Part ial tear Partial tear Comp~e rupture, por tion of patella avu lsed Complete rup ture Partial tea r Complete rupture No op note available Part ial tear Complete rupture No op note available
370
ARTHUR NEWBERG AND LEE WALES
Fig. 5. Oblique projection of the right knee showing multiple discrete corticated fragments (arrow) suggesting avulsion of degenerative spurs from the superior pole of the patella in a patient with ruptured quadriceps tendon.
DISCUSSION
The normal quadriceps tendon is quite strong with an almost parallel array of collagen fibrils producing an ideal physical adaptation for tensile-force transmission and is able to withstand forces up to 15-30 kg/mm 2 (13). Preexisting degenerative change in the tendon as a precursor to rupture is frequently mentioned in the literature (14). The majority of the patients are elderly or obese, and pathological changes in the quadriceps tendon have been documented to be associated with advancing age. Fatty degeneration and tendinosclerosis are found to a marked degree in elderly people (2, 16). Other pathological findings in the tendon include calcification within the collagenous connective tissue, myxoid degeneration, cystic softening and decrease in collagen with marked loss of nuclei (15, 17). In other patients, numerous predisposing factors have been associated with tendon rupture. These include gout (1), systemic lupus erythematosus (4, 18, 19), rheumatoid arthritis (6), hyperparathyroidism (9, 20), chronic renal failure (5), and diabetes mellitus (7,8). Treatment for partial tears is conservative while complete tears require primary surgical repair, preferably within the first 48-72 hours. Delayed diagnosis results in
November 1977
healing by fusion of the calcifying hematoma with resultant lengthening of the quadriceps mechanism and loss of power and instability of the joint (22). Delayed surgical repair may increase morbidity with weakening of the extensor mechanism and lack of knee flexion (1, 14). The history of an attempt to recover after a stumble, immediately followed by a sharp pain just above the knee, should alert the physician to the diagnosis.On examination, the patient is often unable to stand and bear weight on the affected leg and most characteristically cannot act ively extend the affected knee. There is tenderness, ecchymosis, and a palpable soft-tissue defect above the patella. This defect corresponds to the normal position of the quadriceps tendon which has retracted superiorly (1). A large hemarthrosis often follows the tear; therefore, the palpable defect may be obscured (21). Unfortunately, the clinical diagnosis of traumatic rupture of the quadriceps tendon is often initially overlooked (22). After finding stable eructate and collateral ligaments, and reassured by a radiographic report ruling out fracture, the patient may be diagnosed and treated as having a sprain (14). Only later will continued disability bring the patient to the orthopedist. The radiologist can make an important contribution by suggesting the diagnosis on the initial radiographic examination. Although arthrography is useful in diagnosing quadriceps tendon rupture, the combination of plain film and clinical findings is sufficient to make the diagnosis (23). The finding of soft-tissue calcification or fragments of avulsed patella has been noted previously (1,5,7,8,9,22, 24). In patients with underlying metabolic disease, the cause is probably dystrophic calcification . In those patients with delayed diagnosis, the calcification above the patella may represent bone format ion in the hematoma. In most ruptures, however, it represents either degenerative changes in the tendon itself, avulsed bone, or spurs from the upper pole of the patella (Fig. 5). Differential diagnosisof the radiographic findings includes synovial osteochondromatosis, synovial sarcoma, or myositis ossificans. Arthur H. Newberg, M.D. Department of Radiology Massachusetts General Hospital Boston, Mass. 02114
REFERENCES 1. Rockwood CA, Green DP: Fractures. Philadelphia, Lippincott, 1975 , Vol 2, pp 1193-1197 2.
Scuderi C:
Ruptures of the quadr iceps tendon. Am J Surg
95:626-634, Apr 1958 3.
Mason RL: Rupture of the quadriceps tendon. Surg Clin N Am
9:1467-1469, Dec 1929
.
4. Rascher JJ, Marcolin L, James P: Bilateral, sequential rupture of the patellar tendon in systemic lupus erythematosis. J Bone Joint Surg 56A:821-822, Jun 1974 5. Wilson IN: Bilateral rupture of rectus femoris tendons in chronic nephritis. Br Med J 1:1402-1403, 15 Jun 1957 6. Peir6 A, Ferrandis R, Garcia L, et al: Simultaneous and spontaneous bilateral rupture of the patellar tendon in rheumatoid arthritis. Acta Orthop Scand 46:700-703, Sep 1975
Vol. 125
QUADRICEPS TENDON RUPTURE
7. Firooznia H, Seliger G, Abrams RM, et al: Bilateral spontaneous and simultaneous rupture of the quadriceps tendon. Bull Hosp Joint Dis 34:65-69, Apr 1973 8. Brotherton BJ, Ball J: Bilateral simultaneous rupture of the quadriceps tendons. Br J Surg 62:918-920, Nov 1975 9. Preston ET: Avulsion of both quadriceps tendons in hyperparathyroidism. JAMA 221:406-407, 24 Jul 1972 10. MacDonald JA: Bilateral subcutaneous rupture of the quadriceps tendon: Report of a case with delayed repair. Can J Surg 9: 74-77, Jan 1966 11. Hinkamp JF, Pellicore RJ: Bilateral rupture of the quadriceps tendon. Arch Surg 74(Chicago):562-564, Apr 1957 12. Steiner CA, Palmer LH: Simultaneous bilateral rupture of the quadriceps tendon. Am J Surg 78:752-755, Nov 1949 13. Harkness RD: Mechanical properties of collagenous tissues. [In] Gould BS, 00: Treatise on Collagen. New York, Academic press, 1968, Vol 2, Part A, pp 247-310 14. Ramsey RH, Muller GE: Quadriceps tendon rupture: a diagnostic trap. Clin Orthop 70: 161-164, May-Jun 1970 15. Mclaughlin Hl, Francis KC: Operative repair of injuries to the quadriceps extensor mechanism. Am J Surg 91:651-653, Apr 1956
371
Diagnostic Radiology
16. lang HB: Untersuchungentiber Aufbrauchveranderungen an der Quadrizepsshne (Tendolipoidose, Tendoartheromatose, Tendosclerose). Ztschr Orthop 80: 171-194, 1951 17. Lichtensteinl: Diseasesof Bone and Joints. S1. Louis, Mosby, 2nd ed, 1975, pp 226-229 18. TwiningRH, MarcusWY, GareyJL: Tendon rupture in systemic lupus erythematosis. JAMA 189:377-378, 3 Aug 1964 19. Morgan J, McCarty OJ: Tendon ruptures in patients with systemic lupus erythematosis treated with corticosteroids. Arthritis Rheum 17:1033-1036, Nov-Dec 1974 20. Preston FS, Adicoff A: Hyperparathyroidismwith avulsion of three major tendons. New Engl J Med 266:968-971, 10 May 1962 21. Walker J: Ruptureof the quadricepsextensor femoris muscle and of its tendonaboveand below the patella. Am J Moo Sci 3:638-649, 1896 22. Smillie IS: Injuries of the Knee Joint. Baltimore, Williams & Wilkins, 4th ed, 1971, p 184 23. Jelasco DV, Morris GA: Rupture of the quadriceps tendon: diagnosis by arthrography. Radiology 116:621-622, Sep 1975 24. Lewis RW: TheJoints of the Extremities:a RadiographicStudy. Springfield, III., Thomas, 1955, p 70
1
Diagnostic Radiology
Arthur Newberg, M.D., and Lee Wales, M.D.
Traumatic rupture of the quadriceps tendon is anuncommon kneeinjury whichoccurs in the elderly, and/or the obese, andin thosewith underlying systemicdisease. Tenpatients with 13 ruptures havebeen seen at the Massachusetts General Hospital in the last nine years. Clinically, the patientis unable to actively extend the knee. Onthe lateralview of theknee there is loss of normal quadriceps outline anda soft-tissue masswith calcificationrepresenting the retracted quadriceps tendon. Mostpatients havea hemarthrosis. Theclinical diagnosis is often overlooked, andthe radiologist could be the first to suggest the diagnosis. Knee, wounds and injuries. (Knee, other injury, 4(5).4859) • (Knee, other calcification, 4(5).819). (Knee, traumatic hemarthrosis, 4(5) .492). Tendons
INDEX TERMS:
Radiology 125:367-371, November 1977 RAUMATIC RUPTURE of the quadriceps tendon is an uncommon knee injury which causes disruption of the extensor mechanism of the knee. Patellar fractures, patellar tendon rupture, and avulsion of the tibial tubercle constitute the other causes of disruption of the knee ex tensor mechanism. The mechanism of injury is a sudden violent contraction of the quadriceps against the body weight with the knee flexed, as the patient tries to prevent a fall (1). The actual moment of tearing occurs with the patella firmly held against the anterior aspect of the femur buttressed by the medial and lateral condyles, and the muscle exerting maximum contraction (Fig. 1). The tear occurs first in the central portion of the tendon anteriorly, with the medial and lateral fibers subsequently tearing depending on the duration and amount of the force (2). The tear usually occurs 1-2 cm above the patella, but disruption may occur at the musculotendinous junction, in the muscle belly, or at the tendinous insertion into bone. A small fragment of bone may be avulsed from the patella (3). Two patients with traumatic rupture of the quadriceps tendon were recently seen at our institution, and this prompted a review of our previous experience.
T
Fig. 1. Schematic representation of quadriceps tendon rupture. There is proximal retraction of the torntendon resulting in a poorlydefined soft-tissue mass. The adjacent suprapatellar bursa usually contains hemarthrosis secondary to tearof thejoint capsule.
MATERIALS AND METHODS
Ten patients with 13 ruptures of the quadriceps tendon were seen in the last nine years at the Massachusetts General Hospital (TABLE I). Three had bilateral ruptures, a not uncommon finding (4-12). The rupture did not occur simultaneously in 2 of the 3 bilateral ruptures. There were 9 men and 1 woman. The average age was 65 with a range from 43 to 87. Two patients were obese, 2 had mild adult onset of diabetes mellitus, 1 had an elevated serum uric acid, and 1 chronic renal failure (bilateral ruptures). The remaining patients had no underlying medical problems. Radiographs of all but one of the ruptures were available for review and all had surgical confirmation.
All of the patients suffered a fall and sought medical attention within 48 hours following injury. One patient's evaluation was delayed. The most common initial clinical diagnosis was internal derangement of the knee with subsequent orthopedic evaluation, eliciting the diagnosis of quadriceps rupture. All of the patients had anteroposterior and lateral radiographs of the knee, and in none did the radiologist suggest the correct diagnosis. Surgery revealed complete rupture of the quadriceps tendon in 7 cases and incomplete tears in 4 cases. Hemarthrosis was noted in the majority with an associated tear in the capsule of the knee. Detailed surgical reports were
1 From theDepartments of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass. 02114. Accepted for publication in April 1977. shan
367
368
ARTHUR NEWBERG AND LEE WALES
November 1977
Fig. 2. Radiographs (A) and xerograms (B) of both knees illustrating suprapatellar soft-tissue mass, punctate calcifications, disruption of normal quadriceps tendon and obliteration of normal soft-tissue planes .
not available for 2 ruptures. An illustrative case report follows. CASE REPORT A 43-year-old woman with a history of chronic renal failure fell two weeks prior to admission and complained of left knee pain thereafter,
but was able to walk. Four days prior to admission, she fell onto her right knee and thereafter could not walk. Progressive pain and disability led her to seek medical attention. On physical examination, she had bilateral knee effusions, bilateral suprapatellar tenderness, no active right extension, and poor active left extension. Radiographic and xerographic examinations were performed (Fig. 2). Direct surgical repair of the right knee revealed complete rupture of the tendon, calcification of the tendon, and hematoma. She regained full use of the right knee, but
369
QUADRICEPS TENDON RUPTURE
Vo l. 125
Diagnostic Radiology
Fig. 3. Right knee . Note fine calcifications, effusion, and loss of normal fascial planes.
continued weakness and pain of the left knee led to repair four months later. Surgical findings revealed extensive fibrosis in the area of the partial rupture, and a primary anastomosis was performed.
Fig. 4. Left knee demonstrating discrete dense calcification within the retracted quadriceps tendon (open arrow) . There is an effusion present with obliteration of the normal quadriceps tendon outline.
RADIOGRAPHIC FINDINGS
Pertinent radiographic findings were noted in lateral projection and were best seen with soft-tissue technique or xerography. Significant findings were either a small cluster of fine irregular calcifications (Fig. 3), or more discrete coarse calcific densities (Fig. 4) in the suprapatellar region in a poorly defined soft-tissue mass repre-
senting the retracted proximal portion of the disrupted tendon. This calcification was noted in 8/13 knees and was a more frequent finding in cases of complete rupture. The usually well-defined density of the quadriceps tendon was absent in 8/13 knees (Fig. 4). A suprapatellar effusion was identified in 9/13 knees. Minimal degenerative spurring was noted about the patella in 5/13 knees.
TABLE I: SUMMARY OF TEN PATIENTS WITHTRAUMATIC QUADRICEPS TENDON RUPTURE
PATIENT
AGE SEX
HISTOR Y
KNEE
MM PD RS
52 M 67 M 71 M
Fall Fall Fall
R
GP
Fall Fall
R
FS
52 M 64M
DC
43 F
Fall
R
L R
L L
L HP
58M
Fall
R
PH PM AC
78 M 87M 72M
Fall Fall Fall
R
L L
R
EFFUSION
OBUTERATlON OF QUADRICEPS TENDON
SUPRAPATELLAR SOFT-TISSUE MASS
No Yes Yes No No Yes
Ye s Yes Yes Yes Yes Yes
Yes Yes Yes Yes Ye s Yes
Ye s Yes Yes Ye s Yes Ye s
Yes Yes Films not available Yes No Yes Yes
No Yes
Yes Yes
Yes Yes
No Yes Yes Yes
No Yes
No Yes Yes Yes
CALCIFICATION
? Yes
SURGICAL FINDINGS Complete ruptur e Complete rupt ure Complete rup ture Part ial tear Partial tear Comp~e rupture, por tion of patella avu lsed Complete rup ture Partial tea r Complete rupture No op note available Part ial tear Complete rupture No op note available
370
ARTHUR NEWBERG AND LEE WALES
Fig. 5. Oblique projection of the right knee showing multiple discrete corticated fragments (arrow) suggesting avulsion of degenerative spurs from the superior pole of the patella in a patient with ruptured quadriceps tendon.
DISCUSSION
The normal quadriceps tendon is quite strong with an almost parallel array of collagen fibrils producing an ideal physical adaptation for tensile-force transmission and is able to withstand forces up to 15-30 kg/mm 2 (13). Preexisting degenerative change in the tendon as a precursor to rupture is frequently mentioned in the literature (14). The majority of the patients are elderly or obese, and pathological changes in the quadriceps tendon have been documented to be associated with advancing age. Fatty degeneration and tendinosclerosis are found to a marked degree in elderly people (2, 16). Other pathological findings in the tendon include calcification within the collagenous connective tissue, myxoid degeneration, cystic softening and decrease in collagen with marked loss of nuclei (15, 17). In other patients, numerous predisposing factors have been associated with tendon rupture. These include gout (1), systemic lupus erythematosus (4, 18, 19), rheumatoid arthritis (6), hyperparathyroidism (9, 20), chronic renal failure (5), and diabetes mellitus (7,8). Treatment for partial tears is conservative while complete tears require primary surgical repair, preferably within the first 48-72 hours. Delayed diagnosis results in
November 1977
healing by fusion of the calcifying hematoma with resultant lengthening of the quadriceps mechanism and loss of power and instability of the joint (22). Delayed surgical repair may increase morbidity with weakening of the extensor mechanism and lack of knee flexion (1, 14). The history of an attempt to recover after a stumble, immediately followed by a sharp pain just above the knee, should alert the physician to the diagnosis.On examination, the patient is often unable to stand and bear weight on the affected leg and most characteristically cannot act ively extend the affected knee. There is tenderness, ecchymosis, and a palpable soft-tissue defect above the patella. This defect corresponds to the normal position of the quadriceps tendon which has retracted superiorly (1). A large hemarthrosis often follows the tear; therefore, the palpable defect may be obscured (21). Unfortunately, the clinical diagnosis of traumatic rupture of the quadriceps tendon is often initially overlooked (22). After finding stable eructate and collateral ligaments, and reassured by a radiographic report ruling out fracture, the patient may be diagnosed and treated as having a sprain (14). Only later will continued disability bring the patient to the orthopedist. The radiologist can make an important contribution by suggesting the diagnosis on the initial radiographic examination. Although arthrography is useful in diagnosing quadriceps tendon rupture, the combination of plain film and clinical findings is sufficient to make the diagnosis (23). The finding of soft-tissue calcification or fragments of avulsed patella has been noted previously (1,5,7,8,9,22, 24). In patients with underlying metabolic disease, the cause is probably dystrophic calcification . In those patients with delayed diagnosis, the calcification above the patella may represent bone format ion in the hematoma. In most ruptures, however, it represents either degenerative changes in the tendon itself, avulsed bone, or spurs from the upper pole of the patella (Fig. 5). Differential diagnosisof the radiographic findings includes synovial osteochondromatosis, synovial sarcoma, or myositis ossificans. Arthur H. Newberg, M.D. Department of Radiology Massachusetts General Hospital Boston, Mass. 02114
REFERENCES 1. Rockwood CA, Green DP: Fractures. Philadelphia, Lippincott, 1975 , Vol 2, pp 1193-1197 2.
Scuderi C:
Ruptures of the quadr iceps tendon. Am J Surg
95:626-634, Apr 1958 3.
Mason RL: Rupture of the quadriceps tendon. Surg Clin N Am
9:1467-1469, Dec 1929
.
4. Rascher JJ, Marcolin L, James P: Bilateral, sequential rupture of the patellar tendon in systemic lupus erythematosis. J Bone Joint Surg 56A:821-822, Jun 1974 5. Wilson IN: Bilateral rupture of rectus femoris tendons in chronic nephritis. Br Med J 1:1402-1403, 15 Jun 1957 6. Peir6 A, Ferrandis R, Garcia L, et al: Simultaneous and spontaneous bilateral rupture of the patellar tendon in rheumatoid arthritis. Acta Orthop Scand 46:700-703, Sep 1975
Vol. 125
QUADRICEPS TENDON RUPTURE
7. Firooznia H, Seliger G, Abrams RM, et al: Bilateral spontaneous and simultaneous rupture of the quadriceps tendon. Bull Hosp Joint Dis 34:65-69, Apr 1973 8. Brotherton BJ, Ball J: Bilateral simultaneous rupture of the quadriceps tendons. Br J Surg 62:918-920, Nov 1975 9. Preston ET: Avulsion of both quadriceps tendons in hyperparathyroidism. JAMA 221:406-407, 24 Jul 1972 10. MacDonald JA: Bilateral subcutaneous rupture of the quadriceps tendon: Report of a case with delayed repair. Can J Surg 9: 74-77, Jan 1966 11. Hinkamp JF, Pellicore RJ: Bilateral rupture of the quadriceps tendon. Arch Surg 74(Chicago):562-564, Apr 1957 12. Steiner CA, Palmer LH: Simultaneous bilateral rupture of the quadriceps tendon. Am J Surg 78:752-755, Nov 1949 13. Harkness RD: Mechanical properties of collagenous tissues. [In] Gould BS, 00: Treatise on Collagen. New York, Academic press, 1968, Vol 2, Part A, pp 247-310 14. Ramsey RH, Muller GE: Quadriceps tendon rupture: a diagnostic trap. Clin Orthop 70: 161-164, May-Jun 1970 15. Mclaughlin Hl, Francis KC: Operative repair of injuries to the quadriceps extensor mechanism. Am J Surg 91:651-653, Apr 1956
371
Diagnostic Radiology
16. lang HB: Untersuchungentiber Aufbrauchveranderungen an der Quadrizepsshne (Tendolipoidose, Tendoartheromatose, Tendosclerose). Ztschr Orthop 80: 171-194, 1951 17. Lichtensteinl: Diseasesof Bone and Joints. S1. Louis, Mosby, 2nd ed, 1975, pp 226-229 18. TwiningRH, MarcusWY, GareyJL: Tendon rupture in systemic lupus erythematosis. JAMA 189:377-378, 3 Aug 1964 19. Morgan J, McCarty OJ: Tendon ruptures in patients with systemic lupus erythematosis treated with corticosteroids. Arthritis Rheum 17:1033-1036, Nov-Dec 1974 20. Preston FS, Adicoff A: Hyperparathyroidismwith avulsion of three major tendons. New Engl J Med 266:968-971, 10 May 1962 21. Walker J: Ruptureof the quadricepsextensor femoris muscle and of its tendonaboveand below the patella. Am J Moo Sci 3:638-649, 1896 22. Smillie IS: Injuries of the Knee Joint. Baltimore, Williams & Wilkins, 4th ed, 1971, p 184 23. Jelasco DV, Morris GA: Rupture of the quadriceps tendon: diagnosis by arthrography. Radiology 116:621-622, Sep 1975 24. Lewis RW: TheJoints of the Extremities:a RadiographicStudy. Springfield, III., Thomas, 1955, p 70
