Journal of the Royal Society of Medicine Volume 84 March 1991
133
The place of arthrography in the diagnosis and management of meniscal injuries-a 6-year review
S E Evans FRCR' J Chandy FRCR' M J Aldridge FRCS2 Departments of 'Radiology and 20rthopaedics, Coventry and Warwickshire Hospital, Stoney Stanton Road, Coventry CV1 4FH Keywords: arthrogram; arthroscopy; arthrotomy; medial meniscus; lateral meniscus
Summary Four hundred and eighty-seven consecutive knee arthrograms, performed over a 6-year period, are reviewed. Their accuracy is compared with arthroscopy and, where appropriate, with arthrotomy. The increasing accuracy of arthrography has resulted in the acceptance of this method of imaging as a useful and accurate means of examining meniscal injuries in the knee. This has led to far fewer surgical procedures and an overall saving of resources. Introduction In 1982 an arthrography service was set up at the Coventry and Warwickshire Hospital, which specializes in orthopaedics and trauma. Five hundred and eighty knee arthrograms were performed during the period 1982 to 1987, of which the 487 available and sufficiently documented cases are reviewed. Arthrographic findings are compared with arthroscopic findings, and where appropriate the arthrotomy findings are reported. The present review was designed to see whether arthrography had any useful impact on the management of meniscal injuries in the knee and, indirectly, saving of resources. Materials and methods Four hundred and eighty-seven patients were referred to the X-ray department for knee arthrography (Table 1). The mean age of the patients was 34 years, and the ratio of male to female was 2.5: 1. There was an equal distribution between right and left knee arthrograms. The most common clinical presentation was pain with or without swelling as a result of injury. The majority of injuries were sports related. Standard double-contrast arthrographyl was performed with the aid of an arthrostat. Six views of each horn of each meniscus were obtained as the knee was progressively distracted and manipulated. Each investigation lasted 20 min on average. The cost of an arthrogram is approximately £50.
The majority of the arthroscopies (96%) were performed or directly supervised by the referring consultants. Where feasible the torn portions of menisci were removed arthroscopically. The procedure, performed under a general anaesthetic, usually lasted between 30 and 45 min. The running cost of an arthroscopy (excluding capital and staffing costs) is approximately £180, based on an outpatient day case. Where arthrotomy was considered appropriate, it was performed directly after an arthroscopy, after retowelling and rescrubbing. The procedure usually lasted a further 40 min and the cost, to include a longer hospital stay, is about £380 (again excluding capital and staffing costs). Results In this study, generally speaking, when true locking was elicited by a history, a meniscal tear was usually subsequently demonstrated. Otherwise, clinical signs were not attributed with diagnostic predictions2. The oldest patients in this study (over 50 years) tended to present with pain and swelling of the knee, and showed concomitant degenerative changes on the plain knee radiographs. Table 2 lists a breakdown of all tears and other intra-articular abnormalities shown by arthrography. Of the 204 tears diagnosed at arthrography, 14 patients refused arthroscopy, although 8 of them continued to have symptoms. A further 16 patients did not attend for their appointments for arthroscopy. The final outcome of these 30 patients is not known. Of the 174 patients whose final outcome is known, 11 patients with suspicious tears were advised by the radiologist to undergo arthroscopy - six tears were later found and removed. Six patients with obvious posterior horn tears of the medial meniscus had inadequate or no visualization of the tears at arthroscopy and went on to have partial meniscectomies at
arthrotomy.
Table 1. Number and type of investigation by year
Arthrogram
Arthroscopy
Arthrotomy
Year
Number
Normal
Number
Normal
Number
Normal
1982 1983 1984 1985 1986 1987 Total
25 69 96 117 90 90 487
17 41 53 57 35 52 255
14 37 53 58 46 44 252
6 19 25 24 8 8 90
11 23 25 16 11 7 93
6 5 7 2 1 0 21
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Journal of the Royal Society of Medicine Volume 84 March 1991
Table 2. Number and type of meniscal tears
Type of tear
Unspecified Anterior horn Posterior horn Bucket handle Horizontal Vertical Radial Parrot beak Suspicious Frayed Degenerative Multiple Discoid Remnant
Lateral
Medial
15 25 70 19 9 1
3 10 16 3 2 -
-
-
2
9 5 1 9
-
-
1 164
Total
Arthrotomy
Arthroscopy
Arthrogram
Medial
Lateral
6 3 3 1
-
-
-
-
-
-
-
-
4
1 4 1 45
1 -
3
3 2
-
-
-
-
41
120
1 35
-
2 -
16
61
155
There were 30 apparent false positives when compared with the subsequent surgical findings. On closer analysis, 16 patients had tears of the posterior horn of the medial meniscus and on review of these arthrograms it would seem that these tears were missed at arthroscopy. The fact that half of these patients were asymptomatic at follow-up does not necessarily indicate the absence of a tear3. Ten patients had degenerate, but not torn, menisci and two patients had furled menisci. Four patients had normal menisci reported as suspicious on arthrography. There were 15 false negative arthrograms when compared with the subsequent surgical findings. Eleven patients continued to have locking or clicking and four continued to have pain. Most of these patients would have been arthroscoped anyway, having presented earlier in the study. The overall specificity and sensitivity are shown (Tables 3 and 4). Note that when the arthroscopic findings are disputed with respect to the 16 'missed' posterior horn tears of the medial meniscus, the specificity rises to 90%. There were no recorded complications. All patients with tears on arthrography, whether symptomatic or not, were referred for arthroscopy. Eighty-three patients had tears removed arthroscopically, and 61 patients had tears removed at arthotomy. Fourteen patients with small tears at arthroscopy had no further management and were well at follow-up. One hundred and fifty-five tears were diagnosed at arthroscopy, 11 tears were missed at arthroscopy Table 3. Analysis offalse positive arthrograms by year (where arthroscopic diagnosis is undisputed and disputed) Year
Undisputed
Disputed
1982 1983 1984 1985 1986 1987 Total Overall specificity
3 8 9 5 3 2 30 83.1
2 5 5 2 1 1 16 90.1
Lateral
3 7 6 9 10 8 -20 3
10 19 40 28 7 1 1 2 1 4 1 6
205
Medial
Table 4. Analysis of false negative arthrograms by year Year
False negative
1982 1983 1984 1985 1986 1987 Total Overall sensitivity is
2 3 4 4 2 0 15
91%
(excluding the 16 patients already mentioned with posterior horn tears of the medial meniscus). Six of these patients had abnormal arthrograms and continued to experience locking. The other five had normal arthrograms but continued to have significant symptoms. There were also 11 false positive arthroscopies. When arthrotomy was performed to remove the tears, no tears were seen. These 11 false positives occurred in the first half of the review. In all there were 90 normal arthroscopies, and 21 normal arthrotomies - though these were not all unnecessarily performed. Firstly, they included the patients whose arthrograms showed tears later shown to be falsely positive. Secondly, a patient may continue to experience symptoms in the absence of
pathology2. The overall undisputed specificity of arthroscopy was 93% and a sensitivity of 92% was shown. If the 16 posterior horn tears of the medial meniscus are considered to be missed, then the sensitivity falls to 87%. There were six significant postoperative complications, all following arthrotomies. Five wound abscesses and one stitch granuloma needed operative treatment and a prolonged stay in hospital. Sixteen patients developed severe pain and swelling after arthroscopy (11 of these 16 patients had normal arthrograms and arthroscopies). These symptoms subsided after conservative treatment, which included an extended course of physiotherapy.
Discussion Not surprisingly, at the start of our study, arthrography played a relatively minor role in the
Journal of the Royal Society of Medicine Volume 84 March 1991
management of suspected meniscal injuries, with greater emphasis being placed on history and clinical examination. Indeed, comparatively more misinterpretations occurred in the first two years, but a steady improvement was seen thereafter, acceptable figures being reached in the fourth year. The increasing experience of the radiologist was reflected accordingly, with a decrease in false positives and negatives. In particular, the radiologist's diagnosis of the posterior horn tears of the medial meniscus presented a challenge to the arthroscopists as this area is relatively less accessible to them, and a significant number oftears are thus probably missed, though this is difficult to prove exclusively. The decreasing incidence of arthrotomy procedures generally meant that arthroscopic findings (and also arthrographic findings) were difficult to confirm unequivocally. Interestingly, increasing experience of the radiologist did not affect the incidence of misinterpretation of tears in degenerate menisci, with an equal incidence occurring throughout the study. This area remains an identifiable pitfall - balanced somewhat by the awareness of the arthroscopist of the limitations of this diagnosis. With the use ofthe most sophisticated arthroscopes, where removal of tears was made possible, the influence of arthrography became more noticeable. If the arthrographic findings were fairly conclusive of a tear and its position, the patients were booked in as day surgical cases for arthroscopic removal. If some doubt existed then an arthroscopy, and probably arthrotomy, was arranged. The overall specificity of arthrography, 90% (where arthroscopic diagnosis was disputed in 16 patients) is not as high as other workers have achieved4. However, the higher specificities of the last 3 years are more acceptable. Certainly, these figures are acceptable to the clinicians, judged by their ongoing enthusiasm and high regard for the investigations. The very high sensitivity of arthrography in the last 2 years has resulted in a significant decrease in surgical procedures, and unless there is very strong clinical evidence, a normal arthrogram does not now lead to an arthroscopy.
There have been no known complications of arthrography during this review. This review shows that arthrography is accepted as an accurate method of investigating meniscal injuries in the knee. Saving of resources through less surgical intervention where arthrography is normal was noted. The diagnosis of meniscal tears of the knee has advanced significantly with the use of magnetic resonance imaging and is currently and widely believed to be the diagnostic gold standard5'6. The added advantage of MRI being a totally non-invasive procedure makes it a highly desirable means of investigating the knee. However, this is offset by the high cost and relative unavailability ofthe procedure, and certainly in Coventry, as elsewhere in the UK, it cannot be foreseen as being the routine means of investigating the menisci for some years to come. Thus arthrography seems here to stay for the next decade or so, as an effective, essential and integral way of investigating meniscal injuries of the knee.
References 1 Stoker NJ. Knee arthrography. London: Chapman & Hall, 1981 2 Goodfellow JW. Editorial: he who hesitates is saved. J Bone Joint Surg 1980;62-B:1-2 3 Noble K, Erat K. In defence of the meniscus: a prospective study of 200 meniscectomy patients. J Bone Joint Surg, 1980;62-B:7-11 4 Stoker DJ, Renton P, Fulton A. The value of arthrography in the management of internal derangements of the knee. The first 1000. Clin Rad 1981;32:557-66 5 Gallimore GW Jr, Harness SE. Knee injuries: high resolution MR imaging. Radiology 1986;160:450-1 6 Reicher MA, Hartzman S, Bassett LW, Mandelbaum B, Duckwiler GR, Gold EM. MR imaging of the knee, traumatic disorders. Radiology 1987;162:547-51
(Accepted 28 September 1990. Correspondence to Dr J Chandy, Department of Radiology, Coventry and Warwickshire Hospital, Stoney Stanton Road, Coventry CVi 4FH)
135
133
The place of arthrography in the diagnosis and management of meniscal injuries-a 6-year review
S E Evans FRCR' J Chandy FRCR' M J Aldridge FRCS2 Departments of 'Radiology and 20rthopaedics, Coventry and Warwickshire Hospital, Stoney Stanton Road, Coventry CV1 4FH Keywords: arthrogram; arthroscopy; arthrotomy; medial meniscus; lateral meniscus
Summary Four hundred and eighty-seven consecutive knee arthrograms, performed over a 6-year period, are reviewed. Their accuracy is compared with arthroscopy and, where appropriate, with arthrotomy. The increasing accuracy of arthrography has resulted in the acceptance of this method of imaging as a useful and accurate means of examining meniscal injuries in the knee. This has led to far fewer surgical procedures and an overall saving of resources. Introduction In 1982 an arthrography service was set up at the Coventry and Warwickshire Hospital, which specializes in orthopaedics and trauma. Five hundred and eighty knee arthrograms were performed during the period 1982 to 1987, of which the 487 available and sufficiently documented cases are reviewed. Arthrographic findings are compared with arthroscopic findings, and where appropriate the arthrotomy findings are reported. The present review was designed to see whether arthrography had any useful impact on the management of meniscal injuries in the knee and, indirectly, saving of resources. Materials and methods Four hundred and eighty-seven patients were referred to the X-ray department for knee arthrography (Table 1). The mean age of the patients was 34 years, and the ratio of male to female was 2.5: 1. There was an equal distribution between right and left knee arthrograms. The most common clinical presentation was pain with or without swelling as a result of injury. The majority of injuries were sports related. Standard double-contrast arthrographyl was performed with the aid of an arthrostat. Six views of each horn of each meniscus were obtained as the knee was progressively distracted and manipulated. Each investigation lasted 20 min on average. The cost of an arthrogram is approximately £50.
The majority of the arthroscopies (96%) were performed or directly supervised by the referring consultants. Where feasible the torn portions of menisci were removed arthroscopically. The procedure, performed under a general anaesthetic, usually lasted between 30 and 45 min. The running cost of an arthroscopy (excluding capital and staffing costs) is approximately £180, based on an outpatient day case. Where arthrotomy was considered appropriate, it was performed directly after an arthroscopy, after retowelling and rescrubbing. The procedure usually lasted a further 40 min and the cost, to include a longer hospital stay, is about £380 (again excluding capital and staffing costs). Results In this study, generally speaking, when true locking was elicited by a history, a meniscal tear was usually subsequently demonstrated. Otherwise, clinical signs were not attributed with diagnostic predictions2. The oldest patients in this study (over 50 years) tended to present with pain and swelling of the knee, and showed concomitant degenerative changes on the plain knee radiographs. Table 2 lists a breakdown of all tears and other intra-articular abnormalities shown by arthrography. Of the 204 tears diagnosed at arthrography, 14 patients refused arthroscopy, although 8 of them continued to have symptoms. A further 16 patients did not attend for their appointments for arthroscopy. The final outcome of these 30 patients is not known. Of the 174 patients whose final outcome is known, 11 patients with suspicious tears were advised by the radiologist to undergo arthroscopy - six tears were later found and removed. Six patients with obvious posterior horn tears of the medial meniscus had inadequate or no visualization of the tears at arthroscopy and went on to have partial meniscectomies at
arthrotomy.
Table 1. Number and type of investigation by year
Arthrogram
Arthroscopy
Arthrotomy
Year
Number
Normal
Number
Normal
Number
Normal
1982 1983 1984 1985 1986 1987 Total
25 69 96 117 90 90 487
17 41 53 57 35 52 255
14 37 53 58 46 44 252
6 19 25 24 8 8 90
11 23 25 16 11 7 93
6 5 7 2 1 0 21
0141-0768/91/
030133-03/$02.00/0 © 1991 The Royal Society of Medicine
134
Journal of the Royal Society of Medicine Volume 84 March 1991
Table 2. Number and type of meniscal tears
Type of tear
Unspecified Anterior horn Posterior horn Bucket handle Horizontal Vertical Radial Parrot beak Suspicious Frayed Degenerative Multiple Discoid Remnant
Lateral
Medial
15 25 70 19 9 1
3 10 16 3 2 -
-
-
2
9 5 1 9
-
-
1 164
Total
Arthrotomy
Arthroscopy
Arthrogram
Medial
Lateral
6 3 3 1
-
-
-
-
-
-
-
-
4
1 4 1 45
1 -
3
3 2
-
-
-
-
41
120
1 35
-
2 -
16
61
155
There were 30 apparent false positives when compared with the subsequent surgical findings. On closer analysis, 16 patients had tears of the posterior horn of the medial meniscus and on review of these arthrograms it would seem that these tears were missed at arthroscopy. The fact that half of these patients were asymptomatic at follow-up does not necessarily indicate the absence of a tear3. Ten patients had degenerate, but not torn, menisci and two patients had furled menisci. Four patients had normal menisci reported as suspicious on arthrography. There were 15 false negative arthrograms when compared with the subsequent surgical findings. Eleven patients continued to have locking or clicking and four continued to have pain. Most of these patients would have been arthroscoped anyway, having presented earlier in the study. The overall specificity and sensitivity are shown (Tables 3 and 4). Note that when the arthroscopic findings are disputed with respect to the 16 'missed' posterior horn tears of the medial meniscus, the specificity rises to 90%. There were no recorded complications. All patients with tears on arthrography, whether symptomatic or not, were referred for arthroscopy. Eighty-three patients had tears removed arthroscopically, and 61 patients had tears removed at arthotomy. Fourteen patients with small tears at arthroscopy had no further management and were well at follow-up. One hundred and fifty-five tears were diagnosed at arthroscopy, 11 tears were missed at arthroscopy Table 3. Analysis offalse positive arthrograms by year (where arthroscopic diagnosis is undisputed and disputed) Year
Undisputed
Disputed
1982 1983 1984 1985 1986 1987 Total Overall specificity
3 8 9 5 3 2 30 83.1
2 5 5 2 1 1 16 90.1
Lateral
3 7 6 9 10 8 -20 3
10 19 40 28 7 1 1 2 1 4 1 6
205
Medial
Table 4. Analysis of false negative arthrograms by year Year
False negative
1982 1983 1984 1985 1986 1987 Total Overall sensitivity is
2 3 4 4 2 0 15
91%
(excluding the 16 patients already mentioned with posterior horn tears of the medial meniscus). Six of these patients had abnormal arthrograms and continued to experience locking. The other five had normal arthrograms but continued to have significant symptoms. There were also 11 false positive arthroscopies. When arthrotomy was performed to remove the tears, no tears were seen. These 11 false positives occurred in the first half of the review. In all there were 90 normal arthroscopies, and 21 normal arthrotomies - though these were not all unnecessarily performed. Firstly, they included the patients whose arthrograms showed tears later shown to be falsely positive. Secondly, a patient may continue to experience symptoms in the absence of
pathology2. The overall undisputed specificity of arthroscopy was 93% and a sensitivity of 92% was shown. If the 16 posterior horn tears of the medial meniscus are considered to be missed, then the sensitivity falls to 87%. There were six significant postoperative complications, all following arthrotomies. Five wound abscesses and one stitch granuloma needed operative treatment and a prolonged stay in hospital. Sixteen patients developed severe pain and swelling after arthroscopy (11 of these 16 patients had normal arthrograms and arthroscopies). These symptoms subsided after conservative treatment, which included an extended course of physiotherapy.
Discussion Not surprisingly, at the start of our study, arthrography played a relatively minor role in the
Journal of the Royal Society of Medicine Volume 84 March 1991
management of suspected meniscal injuries, with greater emphasis being placed on history and clinical examination. Indeed, comparatively more misinterpretations occurred in the first two years, but a steady improvement was seen thereafter, acceptable figures being reached in the fourth year. The increasing experience of the radiologist was reflected accordingly, with a decrease in false positives and negatives. In particular, the radiologist's diagnosis of the posterior horn tears of the medial meniscus presented a challenge to the arthroscopists as this area is relatively less accessible to them, and a significant number oftears are thus probably missed, though this is difficult to prove exclusively. The decreasing incidence of arthrotomy procedures generally meant that arthroscopic findings (and also arthrographic findings) were difficult to confirm unequivocally. Interestingly, increasing experience of the radiologist did not affect the incidence of misinterpretation of tears in degenerate menisci, with an equal incidence occurring throughout the study. This area remains an identifiable pitfall - balanced somewhat by the awareness of the arthroscopist of the limitations of this diagnosis. With the use ofthe most sophisticated arthroscopes, where removal of tears was made possible, the influence of arthrography became more noticeable. If the arthrographic findings were fairly conclusive of a tear and its position, the patients were booked in as day surgical cases for arthroscopic removal. If some doubt existed then an arthroscopy, and probably arthrotomy, was arranged. The overall specificity of arthrography, 90% (where arthroscopic diagnosis was disputed in 16 patients) is not as high as other workers have achieved4. However, the higher specificities of the last 3 years are more acceptable. Certainly, these figures are acceptable to the clinicians, judged by their ongoing enthusiasm and high regard for the investigations. The very high sensitivity of arthrography in the last 2 years has resulted in a significant decrease in surgical procedures, and unless there is very strong clinical evidence, a normal arthrogram does not now lead to an arthroscopy.
There have been no known complications of arthrography during this review. This review shows that arthrography is accepted as an accurate method of investigating meniscal injuries in the knee. Saving of resources through less surgical intervention where arthrography is normal was noted. The diagnosis of meniscal tears of the knee has advanced significantly with the use of magnetic resonance imaging and is currently and widely believed to be the diagnostic gold standard5'6. The added advantage of MRI being a totally non-invasive procedure makes it a highly desirable means of investigating the knee. However, this is offset by the high cost and relative unavailability ofthe procedure, and certainly in Coventry, as elsewhere in the UK, it cannot be foreseen as being the routine means of investigating the menisci for some years to come. Thus arthrography seems here to stay for the next decade or so, as an effective, essential and integral way of investigating meniscal injuries of the knee.
References 1 Stoker NJ. Knee arthrography. London: Chapman & Hall, 1981 2 Goodfellow JW. Editorial: he who hesitates is saved. J Bone Joint Surg 1980;62-B:1-2 3 Noble K, Erat K. In defence of the meniscus: a prospective study of 200 meniscectomy patients. J Bone Joint Surg, 1980;62-B:7-11 4 Stoker DJ, Renton P, Fulton A. The value of arthrography in the management of internal derangements of the knee. The first 1000. Clin Rad 1981;32:557-66 5 Gallimore GW Jr, Harness SE. Knee injuries: high resolution MR imaging. Radiology 1986;160:450-1 6 Reicher MA, Hartzman S, Bassett LW, Mandelbaum B, Duckwiler GR, Gold EM. MR imaging of the knee, traumatic disorders. Radiology 1987;162:547-51
(Accepted 28 September 1990. Correspondence to Dr J Chandy, Department of Radiology, Coventry and Warwickshire Hospital, Stoney Stanton Road, Coventry CVi 4FH)
135
