Distortion or contusion of the knee is a common trauma in both sports and non-sports related activities. The annual incidence of knee injuries were 110 per 10 000 inhabitants with every tenth injury leading to a surgical consultation to assess the need for operative treatment (
5). Traumatic haemarthrosis of knee presents diagnostic difficulty in acute injury stage, it limits knee investigation and it should be disabled because of the pain. Nowadays, patient with acute knee haemarthrosis should be definitely admitted to orthopedic or trauma surgery department ( 6).
In the current study, at least one ACL test under anesthesia had positive result in 61.4% of cases, and also ADT and the Lachman tests were more accurate ACL tests. This finding was consistent with those of some studies by Noyes et al., Butler et al., Casteleyn et al. and Hardaker et al. In these studies, they reported that under anesthesia, the Lachman test was the most reliable one (
1- 4). Hardaker et al. reported Patients’ responses to preoperative anterior drawer, pivot shift, and Lachman tests were within normal limits in 18%, 29%, and 73% of cases, respectively ( 4). However, Maffuli et al. found pivot shift test slightly better ( 7). They were unable to perform pivot shift test primarily on some of the patients because of pain and protective guarding, however with general anesthesia it was possible to elicit this test ( 1, 3, 4). Ostrowski et al., conducted a meta-analysis of 17 studies on accuracy of physical diagnostic tests to assess ruptures of the ACL. According to the predictive value statistics, they reported that during the physical examination, a positive result for the pivot shift test is the best to rule in an ACL rupture, whereas a negative result to the Lachman test is the best to rule in an ACL rupture. Also they concluded that, solely using sensitivity and specificity values, the Lachman test is a better overall test in both ruling in and ruling out ACL ruptures ( 8).
According to the current study findings, ACL was the most injured knee structure in traumas not leading to bone fracture and the most prevalent source of bleeding in the knee injuries. This finding was consistent with those of the studies by Noyes et al., Casteleyn et al., Sarimo et al., Fanelli et al., Bilik et al., Stanitski et al. and Sperner et al. (
1, 3, 5, 6, 9- 11).
The most common associated injury with ACL tearing was menisci, which was consistent with the results obtained by Noyes et al. and Casteleyn et al. (
1, 3). The current study found 2 (4.5%) PCL tears. It was considerably lower than the incidence of 44% reported by Gregory et al. A probable reason for the lower incidence of PCL injuries in sport traumas in comparison to those of other traumatic injuries is the mechanism of injury. This result was similar to that of the reported incidence of 1% - 23% in the literature ( 3, 12- 14).
The importance of correct diagnosis and early treatment in patients with hemarthrosis of the knee are demonstrated in various studies (
3, 15- 17). It is emphasized that undiagnosed and untreated knee injuries have poor outcomes. Experience gained in evaluating posttraumatic hemarthrosis of the knee suggests that clinical examination alone may not demonstrate the severity of many of these injuries. According to the findings, it was concluded that examination under anesthesia plus arthroscopy allows a more accurate diagnosis of acute traumatic hemarthrosis of the knee. However, in a study on a total of 85 injured knees over a 125-week period, Hardaker et al., concluded that arthroscopy is invaluable to determine the existence of other injuries with or without an associated ACL tear ( 4).
Swelling, pain and various degrees of inability to move the knee following the trauma are common early signs. The most frequent complaints in the current study were swelling, pain and giving way which were similar to the results reported by Noyes et al. (
In daily practice when a patient presents a history of knee trauma, swelling, pain and episodes of giving way complains of chronic pain and signs of knee joint arthrosis. Early diagnosis of knee hemarthrosis and arthroscopic examination cuts out this unhappy phenomenon. Early diagnosis of ligament derangements, particularly ACL, helps accurate and proper management. The current study confirmed ACL as the most injured knee structure in traumas not leading to bone fracture and as the most prevalent source of bleeding in knee injuries.
The current study had some limitations: first, its cross-sectional nature did not allow conclusions of causality on the observed associations. Second, the sample size was relatively small. One of the reasons was that, nowadays new technologies and devices such as MRI are widely used in diagnosis especially in knee injuries, and the patients which diagnosis was confirmed by physical examination or MRI were not included in the study.
In a patient developing knee hemarthrosis after trauma, the surgeon can diagnose the etiology with history taking, physical examination and MRI, he (she) can treat it, but in the case of doubts, the surgeon can perform an arthroscopy which is a minimally invasive procedure that could be done under local or regional anesthesia to make a correct diagnosis and proper treatment to prevent later complications such as meniscal tear and injury to cartilage.