Radiological errors in orthopaedics and its medico-legal implications

Radiological errors in orthopaedics and its medico-legal implications

                              Dr KS Dhillon FRCS, LLM

The work of a radiologist involves detecting and describing imaging abnormalities and coming up with an accurate diagnosis. Though errors are an inevitable part of medical practice, these errors however can lead to medical malpractice claims. Medical malpractice claims have been on the rise in USA since the early 1970’s (1) and in Malaysia anecdotal evidence shows that such claims are also on the rise in the last few decades. In the USA radiology is one of specialities which is most liable to negligence suits (1). However it is not common to hear of negligence claims against radiologist in Malaysia but it is matter time before such claims become common.

About 12% of all negligence suits filed in the USA is related to radiological procedures or the radiologist (2, 3). Missed radiological diagnosis accounts for about 40% to 47% of the law suits. About 30% of suits are related to failure to order radiological examination (3). The most common type of missed diagnosis involves fractures followed by missed malignancies (2). The most commonly missed fractures are that of the femur, navicular bone and the cervical spine and bone tumours on plain radiographs feature among the commonly missed malignancies (1). The average error rate among radiologist in the USA is around 30% (1). The common reasons why malpractice claims are brought against radiologist include ‘observer errors, errors in interpretation, failure to suggest the next appropriate procedure and failure to communicate in a timely and clinically appropriate manner’ (1).

Errors in radiology

There are three types of observer errors which are common and these include scanning, recognition and decision making errors. Scanning errors result from failure to fixate at the abnormal lesion and recognition errors result from ability to fixate at the correct site but fail to recognise the abnormality. Decision making errors result from interpreting an abnormality as a normal structure (4). The most common error is decision making error (45%) followed by scanning error (30%) and recognition error (25%) (4).

Errors in interpretation

Interpretation errors occur because of lack of clinical knowledge about the patient, failure to look for previous studies done, poor index of suspicion, low level of vigilance and distraction by the abnormality detected which leads to failure to look for other abnormalities (1).

Failure to suggest the next appropriate procedure

Following the reporting of any abnormality on radiological imaging, if there are follow-up studies needed to clarify or confirm the impression, then the radiologist is duty bound to communicate this to referring physician. Failure to do so may expose the radiologist to a possible negligence suit (1).

Failure to communicate in a timely and clinically appropriate manner

Where appropriate, the radiologist should communicate important findings of imaging to the referring physician, though the final imaging report has been written and signed. The communication should be documented with details of what was communicated. Errors in communication have been responsible for malpractice claims (1).

Missed fractures

Errors in diagnosis of fractures are very common in the Accident and Emergency department.  Guly (5) collected data of missed injuries in a district hospital in the UK between 1992 and 1996. There were 953 diagnostic errors in 934 patients. About 80% of the diagnostic errors were missed fractures. Seventy-eight percent of the errors were due to misreading of the radiographs. Complaints and legal actions resulted from 22 of the diagnostic errors and 3 patients with diagnostic error died.

A systematic analysis of missed extremity fractures in emergency medicine was carried out by Wei et al (6). They reviewed 2,407 new patients in the emergency department who had extremity fractures from Jan 2003 to June 2004. The images were independently reviewed by an emergency radiologist and a musculoskeletal radiologist. They found a 3.7% overall rate of missed fractures. The location of the most frequently missed fractures was the foot (7.6%), followed by the knee (6.3%), elbow (6.0%), hand (5.4%), wrist (4.1%), hip (3.9%), ankle (2.8%), and shoulder (1.9%). Of the initially missed fracture, 70% were identified and only 33% of the initially missed fractures were attributed to radiographically imperceptible lesions. The shaft fractures are less often missed since they are usually clinically evident as compared to periarticular fractures which often clinically less evident.
In a retrospective study of multiple trauma patients admitted to the intensive care unit of a major teaching hospital, Frawley (7) found that a delayed diagnosis of missed injuries was made in 40% of patients.

For a radiologist to accurately interpret the radiological images, the radiologist needs information about the circumstances of the injury, a good clinical history and clinical findings which is often not available to the radiologist. Another reason why fractures are often missed is called the satisfaction of search (SOS) phenomena. This occurs when the radiologist detects a fracture on one image and this detection interferes with detection of a more subtle fracture in other images of the same patient. The gaze on the detected fracture has been found to be longer compared to the gaze time on other images (8).

Renfrew et al (9) reviewed and classified errors in radiology after reviewing 182 cases that were presented at problem case conferences from 1986 to 1990. They found that the sources of errors had not changed over 20 years. They found that errors involved;

1. ‘failure to consult old radiologic studies or reports,
2. limitations in imaging technique,
3. acquisition of inaccurate or incomplete clinical history,
4. location of a lesion outside the area of interest on an image,
5. lack of knowledge,
6. failure to continue to search for abnormalities after the first abnormality was found,
7. failure to recognize a normal biologic variant’

One hundred and twenty six were perceptual errors (64 false-negative, 15 false-positive, and 47 misclassification errors) and 56 were mishaps which included 38 complications and 18 communication errors.

Value of radiologists’ interpretation of radiographs

Clark et al (10) studied the clinical value of radiologists’ interpretations of peri-operative radiographs in orthopaedic patients. Their aim was to find out whether the radiology reports provided sufficient information which is necessary to make clinical decision. They retrospectively reviewed 371 radiographs of 211 consecutive patients. The reports were generated by 3 Board-certified radiologists. They evaluated the accuracy of description and assessment of the fractures and the implants used for fracture stabilization.

They found that fracture descriptions were complete for 85% of reports and the assessment of alignment and displacement (necessary to determine fracture care) was complete in only 9% of the reports. Precision of description of orthopaedic implants was accurate in 12% of the reports and 7% of the descriptions were in error. The description of effect of the implants was precise in 27% and the description of the position of the implants was accurate in 25% of the cases. Implant stability was assessed precisely in only 4% of cases. In 61% of the pre-operative studies the radiologists report was not available till after the surgery had been completed. The authors concluded that ‘the attending orthopaedic surgeon has traditionally interpreted such radiographs and should continue to do so to provide patients with more immediate and complete clinical evaluation and management’.
Crockett et al (11) did a retrospective analysis of radiographic reports of 161 consecutive patients with idiopathic scoliosis to assess their clinical value in surgical decision making and the usefulness of the reports in assessing post-surgical outcome. The reports were prepared by one of seven Board-certified radiologists and one of two Board-certified orthopaedic surgeons.

The presence of scoliosis was mentioned in 95% of the radiologist reports and in 99.4% of the orthopaedist reports. The type of curve was described in only 5% of the radiologist reports whereas it was described in 99.4% of the orthopaedist reports. The progression of curve was recorded in 16.7% and magnitude of the curve in 12.6% of the radiologist reports as compared to 98.4 and 98.1% respectively in the orthopaedist reports. The level of curve was reported in 10.6% of the radiologist reports and in 95.6% of the orthopaedic reports. The radiologist reported kyphosis in 28% and lordosis in 26.5% of the reports while the orthopaedist reported kyphosis in 98.2% and lordosis in 79.45% of the reports.

The radiologist noted the presences of instrumentation in 77.8% and fusion in 68.3% of the reports while the orthopaedist noted instrumentation in 84.4% and fusion in 100% of the reports. The radiologist misreported fusion in 7% and misidentified the instrumentation in 20% of the reports.
The authors concluded that the orthopaedic spine surgeons did not gain anything useful from the radiologist’s reports.

Radiologist and malpractice suits

In the USA radiologists comprise 3.6% of all physicians but they ranked number 6 among specialist who had claims closed where they were defendants. They were sued more often than plastic surgeons, anaesthesiologist, cardiologist and gastroenterologist but less often than obstetricians, internist, general surgeons and orthopaedist (12).

Berlin and Berlin (13) reviewed all malpractice suits in Cook County, Illinois, USA between 1975 and 1994. Among the suits involving the radiologists, errors in interpretation was the main concern in 55% of the cases from 1975 to 1979 and it was up to 71% of the cases from 1990 to 1994. Misdiagnosis of bone abnormalities especially fractures topped the list.

More recently Whang et al (12) reviewed the credentialing data of 8,401 radiologists to determine the most frequent causes of malpractice suits among radiologists. They found that the most common general cause was error in diagnosis (14.83 claims per 1000 person-years). In the category of missed diagnosis, breast cancer was the leading cause of litigation followed by non-spinal fractures, spinal fractures, lung cancer and vascular disease.
The other leading cause of malpractice suits was procedural complications followed by inadequate communication with patient and the referring physician. Failure to order additional test was a rare cause of malpractice suits.

A study, by Baker et al (14), of the demography of medical malpractice suits against radiologists showed that 30.9% of radiologists in the USA are the subject of a malpractice suit at least once in their career. The likelihood of a radiologist being sued is 50% by the time the radiologist reaches the age 60. The study found that male radiologists are sued more often than female radiologist.

The most common injuries of the muscular skeletal system (excluding the spine) for which malpractice suits are brought against the radiologist are foot and hip injuries. The highest settlement in the USA for musculoskeletal injuries (excluding the spine) is for the ankle injuries (15).

Of the malpractice suits brought against radiologist in the USA 13.2 % are related to the bones and adjacent soft tissue and 32.9% involve the spine. The cervical spine was involved in 68.2 % cases followed by the lumbar spine in 16.5% and the thoracic spine in 15.3% of the cases. The highest settlement has been for the cervical spine (average settlement of $483,156) followed by thoracic spine (average settlement of $481,608) and the lumbar spine (average settlement of $119,272 (16).

Improving quality of diagnostic radiology reporting

In the USA, The Joint Commission (TJC) had in 2007 introduced the Ongoing professional Practice Evaluation (OPPE) and Focused Professional Practice Evaluation (FPPE) processes to help monitor the performance of all medical professionals granted privileges in a hospital. OPPE helps identify practitioners who may be delivering unacceptable quality of care and the FPPE is a follow-up process to determine the validity of the findings of the OPPE. The review, decision and follow-up process is developed and implemented at each department level.

The American Board of Medical Specialist (ABMS) has introduced a program for Maintenance of Certification (ABMS MOC) to address the problem of physicians losing knowledge and skills as the years pass after their training (this has been repeatedly shown by research). The American Board of Radiology requires all diplomates with 10-year, time-limited primary or subspecialty certificates to successfully complete the requirements of the appropriate ABR MOC program for their specialty or subspecialty to maintain their certification. The MOC addresses six competencies which include ‘medical knowledge, patient care, interpersonal and communication skills, professionalism, practice-based learning and improvement, and systems-based practice’ (17). The practice performance module includes peer review and double-reading assessment. One of the popular peer review programme is the RADPEER quality assurance program. This peer review system ‘adds minimally to workload, is confidential, uniform across practices’. The radiologist who ‘review previous images as part of a new interpretation record their ratings of the previous interpretations on 4 point scale’. The ratings are then reviewed by a peer review committee and the ‘final ratings are then sent for central data entry and analysis’ (18). Such a system of peer review can help reduce errors and improve performance of the radiologist.

Radiology reporting in Malaysian private hospitals

The causes of errors in radiological reporting have been identified to include the following (9):

• ‘failure to consult old radiologic studies or reports,
• limitations in imaging technique,
• acquisition of inaccurate or incomplete clinical history,
• location of a lesion outside the area of interest on an image,
• lack of knowledge,
• failure to continue to search for abnormalities after the first abnormality was found,
• failure to recognize a normal biologic variant’

The practice in Malaysian private hospitals is to return all radiological films to the patient when the patient leaves the hospital. A copy of the report is in the patient’s medical file which is not with the radiologist when they report on subsequent images. The images are obtained by the radiographers and invariably there is no contact between the patient and the radiologist. Most often even if the images are not up to the mark the radiologist invariable goes ahead and reports the findings on the images rather than take the trouble to order new imaging. The patient’s clinical history is invariably not available to the radiologist. Sometimes the radiologist is overwhelmed by the workload to spend a lot of time on the images to be interpreted. Of course there is no recertification of the radiologists to make sure that they have not lost the knowledge and skill since their training was completed.

Furthermore there is a lack of subspecialty radiologists and most hospitals have general radiologists who report all investigations done for all medical specialities. Communication between the radiologist and the referring physicians is almost non-existent. With all these drawbacks the error rates are expected to be high. To my knowledge the incidence of error rates for radiological reporting in Malaysia are not available. The interpretive value of reporting by orthopaedic surgeons for orthopaedic imaging has been reported to be high as compared to that by radiologist. Therefore it is incumbent on all orthopaedic surgeons to report all the imaging themselves although there is a report written and signed by the radiologist.

Conclusion

Malpractice claims are on the rise in most western nations and also on the rise in Malaysia. In the USA 40% to 47% of the malpractice claims against the radiologist are for missed diagnosis. Missed diagnosis involving fractures is one the most common cause of malpractice suits. The average rate of missed diagnosis in the USA has been reported to be as high as 30% and one study from Australia quoted a figure of 40% of initial missed diagnosis in patients admitted to the intensive care unit. The causes of errors in diagnosis has been studied and reported in the literature. In the USA several programs have been instituted to address these problems. However in Malaysia the rates of missed diagnosis in radiological reporting are not known. It is likely to be much higher than that in the west. To my knowledge there are no programs in place to improve the existing status of radiological reporting.

Finally, review of literature shows that the interpretive value of reporting, of orthopaedic imaging, by the orthopaedic surgeons is very much higher as compared to that by the radiologists. Therefore it is incumbent on orthopaedic surgeons to interpret and report all imaging carried out on their patients despite the existence of a report by a radiologist. This would be consistent with our duty to care for the patient to prevent foreseeable injury which may lead to tortious liability.

References

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