THE DIFFERENTIAL DIAGNOSIS OF ACUTE KNEE INJURIES WITH HEMARTHROSIS

Objectives: This study was performed to answer the following questions: First, does the knee examination under general anesthesia (GA) and arthroscopy allow a more accurate diagnosis? Second, what is the incidence and the differential diagnosis of injured knees with hemarthrosis. Methods: This retrospective study was performed on 350 cases from a single center with complaints of knee pain and swelling. Results: Seventy out of the 350 cases were selected based on inclusion and exclusion criteria. The average age was 30.6 years. The right knee was injured in 44.3%; left knee in 55.7%. A professional sport level was in 17.1%; a recreational was in 82.9%. Indirect injury caused 71% and 29% were caused by direct injury. Lachman test at emergency was positive in 38.6%; negative in 38.6%; difficult to perform in 17%; not examined in 5.7%. Under GA, Lachman test was positive in 81.4%; negative in 10%; sensitivity of physical examination for diagnostic acute ACL injury at follow up visit in orthopedic outpatient department. Knee joint aspiration in acute ACL injury with suspected hemarthrosis could be considered as a diagnostic procedure (1).


ISSN: 2320-5407
Int. J. Adv. Res. 8(02), 1214-1221 1215 sensitivity of physical examination for diagnostic acute ACL injury at follow up visit in orthopedic outpatient department. Knee joint aspiration in acute ACL injury with suspected hemarthrosis could be considered as a diagnostic procedure (1).
Among the non-invasive clinical diagnostic tests available to us, the Lachman test has proven to be the most reliable (2). The Lachman, anterior drawer, and pivot shift tests are used to establish a diagnosis of ACL deficiency (2). The uninjured knee should always be examined for a baseline comparison. The Lachman test is the most sensitive in a patient who is awake (3). The sensitivity of the Lachman test approaches 81% (3). When assessing the endpoint, the examiner feels for the ACL limiting the amount of shifting of the shin bone. Typically, an examiner will describe the endpoint as either "firm" or "soft." A firm endpoint implies the ACL is doing its job to limit the amount of movement in the knee joint. A soft endpoint is indicative of the ACL not functioning well and other structures (the secondary stabilizers) limiting the amount of movement in the joint.
The significance of the injury was first appreciated by Gillquist et al. (4), Noyes et al. (5), and DeHaven (6). Gillquist et al. (4), on the basis of a study on 69 knees, found that 59% of patients had an ACL tear that was diagnosed on preoperative examination in only 15% of patients. This percentage increased to 32% when the patients were examined under general anesthesia (GA).
In a study by Bomberg and McGinty (1990) (7), 72% of patients had an ACL injury and 62% had a meniscal injury, usually associated with an ACL tear (7). Only 24% of the complete ACL tears were diagnosed preoperatively. When these knees were examined in patients under GA, 56% of the complete ACL tears were diagnosed preoperatively.
In DeHaven's series (6) of 113 stable athletic injuries, 72% had an ACL tear, 15% had an isolated meniscal tear, and 6% had an osteochondral fracture, which was not detected on plain radiographs. DeHaven in 1980 (8) reported that the Lachman test was very reliable for the diagnosis of ACL tears and was expected to provide positive results in 85% of patients without anesthesia and in 100% of patients under GA.
This retrospective study was performed to define the current role of diagnostic arthroscopy for acute knee injury with post-traumatic hemarthrosis to answer the following questions: 1. Does the examination under GA and arthroscopy allow a more accurate diagnosis of injury to joint structures? 2. What is the differential diagnosis of hemarthrosis?

Patients and Methods:-
This retrospective study was performed on 350 cases admitted to Vrinnevi Hospital, Norrkoping, Sweden, with complaints of knee pain and swelling during activities of daily living like sports, dance, etc. Study data were collected over 4 years. The study was approved by the Orthopedic department of Vrinnevi Hospital.

Selection of Patient files:
The patients' files were selected according to the code data program number of arthroscopies. We collected 350 files (all of the patients had undergone arthroscopy).

Inclusion and exclusion criteria:
All the 350 patients' medical records were filtered according to the inclusion and exclusion criteria. The inclusion criterion was pure blood aspirated from the injured knee. Patients with unclear blood (mixed with fat drops) aspirated from the knees were excluded.

Data Collection:
All data were collected retrospectively from patient files and arthroscopic findings [ Table 1]. These protocols were completed by the operating surgeon directly post-operatively. Subsequently, these protocols were entered into a database. The knee injuries were classified. The patient's age, knee site, sport level, and mechanism of injury were registered.

Examination at emergency:
All patients were seen in the emergency department. Anteroposterior and lateral plain radiographs were taken in all cases. The presence of knee hemarthrosis was confirmed by needle aspiration. The aspiration process was performed by an emergency doctor (consultant, specialist, or resident). Lachman test was performed if the patient could tolerate it.

Preoperative examination:
Preoperatively, the Lachman test was performed under GA in the operating room.

Arthroscopic examination:
This was performed under GA by the "knee team" (specialist and consultant). At arthroscopy, anterolateral and anteromedial portals were used; other portals were used as required. All the knee compartments were examined. Tourniquets were not used.

Arthroscopic ACL examination:
A blunt hook-shaped probe was used to examine the ACL through an appropriate entry portal. Tension of the ACL fibers was evaluated by pulling the ACL with a hook. ACL tears were classified as partial or complete on the basis of visual inspection and probing.

Meniscal injuries:
Meniscal tears have been classified based on appearance as longitudinal < 1 cm and > 1 cm, horizontal, radial, bucket-handle, and complex tears (9). All data were collected retrospectively using an arthroscopic protocol and were entered into a database. All other knee structures, such as the patella, posterior cruciate ligament (PCL), tibia, and femoral cartilage surfaces, were examined.

Data Analysis:
Statistica 7.1 -2005, in Swedish language for the data analysis was used.

Results:-Patient and injury characteristics:
A total of 70 cases were selected based on our predefined inclusion and exclusion criteria. The average age of the patients was 30.6 (15-54) years. The right knee was injured in 31 (44.3%), while the left knee in 39 out of 70 cases (55.7%). A professional sport level was found in 12 cases (17.1%), while a recreational sport level was found in 58 cases (82.9%). Fifty out of 70 cases (71%) were caused by indirect (non-contact) injury (e.g. turning, twisting, or jumping off the planted foot). However, 20 out of the 70 cases (29%) were caused by direct injury.

Lachman test at emergency:
Lachman test at emergency was positive in 27 cases (38.6%) and negative in 27 cases (38.6%). It was clearly difficult to perform a Lachman test in 12 cases (17%). On the other hand, the remaining 4 cases (5.7%) were not examined.

Discussion:-
This study confirms the very serious nature of acute traumatic knee hemarthrosis, which is usually represented by an ACL tear that could be undetected unless examined arthroscopically.
We found that examination of patients under GA markedly increased the accuracy of the Lachman test in diagnosing a complete ACL. The data are representative of previous reports that the ACL tear is the most common injury and often occurs as an isolated ligamentous injury (6,7,10).
Knee joint aspiration in acute ACL injury with suspected hemarthrosis could be considered as a diagnostic procedure (1). So, if we have a patient with knee hemarthrosis in outlying area and we don't have advanced equipments like magnetic resonant image (MRI), we can use arthrocentesis to diagnose the knee injury or at least to classify the injury as a severe injury.
There are a number of limitations that need to be considered. The data was collected only from a single hospital; thus, the results may not be generalizable. The sample size was very small. To overcome these limitations, a larger study that excludes all the limitations should follow.
In summary, aspiration of hemarthrosis in a traumatic knee is a good indicator for ACL injury.
Our results are representative of the reports that ACL tear is the most common injury and often occurs as an isolated ligamentous injury, and noted that combined injuries, such as meniscal tears, chondral injury, PCL tears, and MCL tears, are infrequent causes of posttraumatic hemarthrosis.

F I G U R E 1 : N U M B E R O F A C L R U P T U R E
Number of ACL Rupture out of Total 70 Cases Figure 2:-ACL Diagnosis.