The
O’Donoghue triad
revisited
Combined knee injuries involving anterior cruciate and medial collateral ligament tears K. DONALD
SHELBOURNE,* MD, AND PAUL A. NITZ, MD
From the Methodist
Sports Medicine Center, Indianapolis, "protect" joint surfaces,
ABSTRACT
most
We identified 60 consecutive patients with combined anterior cruciate and medial collateral ligament (ACLMCL) disruptions that were incurred during athletic endeavors. Each underwent acute reconstruction of the ACL. The arthroscopic data obtained at the time of reconstructive surgery was reviewed in order to determine the incidence of O’Donoghue’s triad (the "unhappy triad"), consisting of ACL, MCL, and medial meniscus
with these injuries absence of further
patients
demonstrate
commonly abnormality (meniscal
intraarticular
an
or
chondral).
In his landmark 1936 monograph, Campbell’ described a &dquo;combination&dquo; knee injury involving disruption of both the anterior cruciate and medial collateral ligaments (MCL), along with a tear of the medial meniscus. He further documented the occurrence of this constellation of findings in his article on ligament reconstruction in 1939.1 O’Donoghue’s publications during the 1950s18-2o regarding athletic knee trauma renewed awareness of such injury combinations-they gained wide recognition among physicians, coaches, and athletic trainers. Across the country, the association of ACL, MCL, and medial meniscus tears became known as the O’Donoghue triad.12, 1 Today, the &dquo;unhappy triad&dquo; is broadly acknowledged; the natural assumption follows that this type of injury occurs frequently. Based on our clinical impression, gained from extensive experience with athletic knee injuries, we began to question whether the widespread familiarity with the terrible triad correlated with the frequency of its occurrence. Accordingly, we retrospectively examined the records of 60 consecutive patients over a 6 year period who suffered ACL-MCL disruptions during athletic participation. All patients underwent arthroscopy and ACL reconstruction by the senior author (KDS). Surgery was performed in the acute postinjury phase (30 days or less postoperatively), without intervening attempts to fully rehabilitate patients and return them to competitive athletics. In this way we could reasonably expect the data to reflect the actual consequences of the index injury. We focused our attention on intraarticular abnormalities revealed by arthroscopy, and evaluated results by comparing patients with an incomplete (second-degree) MCL injury to those with a third-degree tear. It was not our intent to analyze the possible mechanism
tears. Patients were subdivided into two groups for analysis based upon the degree of MCL injury at time of presentation (Group I, 35 patients with a second-degree sprain; Group II, 25 patients with a complete, or thirddegree injury). Medial meniscus tears were an uncommon finding. Lateral meniscus tears significantly outnumbered medial meniscus tears in both groups, occurring in 25 (71 %) of GroupI patients and 8 (32%) of those in Group II. Even chondral fractures of the lateral femoral condyle outnumbered medial meniscus tears [6 (17%) versus 4 (11 %)] in patients with a seconddegree MCL sprain. Furthermore, when present in GroupI patients, tears of the medial meniscus were associated with a concomitant lateral meniscus injury. Group II patients were more likely (60%) than GroupI not to have any meniscal abnormality at all. We conclude that the classic O’Donoghue triad is, in fact, an unusual clinical entity among athletes with knee injuries; it might be more accurately described as a triad consisting of ACL, MCL, and lateral meniscus tears. This injury combination appears to be more common when an incomplete, or second-degree, tear of the medial collateral has occurred. Third-degree MCL injuries in conjunction with ACL disruptions seem to *
Address correspondence and reprnt requests to. K Donald Shelbourne, MD, Methodist Sports Medicme Center, 1815 N Capitol Avenue, Suite 530,
Indianapolis,
as
Indiana
IN 46202. 474
475
of injury, but rather to summarize the arthroscopic findings and share our observations in this group of injured athletes.
TABLE 1
Activity associated with index knee injury ___
MATERIALS AND METHODS
Sixty patients (49 men and 11 women) seen at the Methodist Sports Medicine Center between January 1983 and April 1989 were included in the study. Those in the study population represent a subset (17%) of 350 patients from our practice who were treated for acute ACL insufficiency during the same period of time. This percentage is consistent with previous reports&dquo;> 17, z2 regarding the number of patients with combined ACL-MCL injuries in relationship to total cases of anterior cruciate injury. As such, these 60 individuals comprise a large, representative group of consecutive patients sustaining a combined, acute ligamentous injury (ACL and MCL) during athletic participation. Each patient underwent arthroscopy and ACL reconstruction within 30 days (range, 1 to 28) following the date of original injury. There was no history of antecedent knee trauma in any patient, nor were any episodes of trauma or instability documented subsequent to the index injury (i.e., prior to surgical management). ACL injury was diagnosed by demonstration of positive Lachman and flexion rotation drawer tests at the time of initial clinical assessment. Examination in the operating room following induction of general anesthesia confirmed initial clinical impressions in all cases. For comparative purposes, patients were divided into two groups based upon the degree of MCL injury. Second-degree MCL injuries (35 patients) were defined as those with medial joint line opening (&dquo;gaping&dquo;) 5 to 10 mm greater than the contralateral knee upon application of a valgus stress with the knee flexed to 30° (Group I). Third-degree collateral injuries (25 patients) had greater than 10 mm of medial joint line opening compared to the uninjured knee on valgus stress, with absence of a clear endpoint to the stress examination (Group II). Grading of the MCL injury was determined by the senior author at the time of initial office assessment; examination was repeated in the operating room with the patient under general anesthesia. All intraarticular injuries were recorded following arthroscopic assessment of the injured knee. Specifically, the presence, location, and type of each meniscal tear and chondral injury were noted. For clarification, only tears through the cartilaginous substance of the meniscus were tabulated; meniscocapsular tears were not included. Data were stored on a computer and comparative results from Groups I and II were analyzed statistically using P values to determine the presence of significant differences.
°b Hockey, pole vaulting, ballet. Frisbee, badminton, water skiing, baseball, volleyball, kicked by a bull.
Figure 1. GroupI distribution of meniscal tears. Note: The first group (32%) are isolated lateral tears; the second group (8%) are isolated medial tears. ball (25% ). Second-degree and third-degree medial collateral injuries were nearly evenly distributed between these two
sports. Acute chondral fractures were found in 8 of the 35 (23%) patients in Group I and 3 of the 25 (12%) patients in Group II. Lateral femoral condyle injuries were found in six (17%) patients in Group I, whereas only two (8%) patients in Group II sustained a similar injury. No medial condylar fractures were recognized in either group. Two patients (6%) in Group I sustained a lateral tibial spine fracture as part of the injury complex; these fractures were associated with meniscal abnormality. Twenty-five patients (71% ) in Group I had a total of 28 acute lateral meniscal tears at the time of arthroscopy (Fig. 1). These tears were classified as one of four types: posterior horn avulsion, peripheral lateral meniscal tear, bucket-handle tear, or radial oblique tear. Three patients had a posterior horn avulsion of the lateral meniscus in addition to a radial tear. Radial oblique tears nearly outnumbered all other types of lateral meniscus tears combined for patients with a second-degree MCL injury (Table 2). Eight Group II patients sustained one of the four types of lateral meniscal tears (32% incidence); no single type of tear
oblique
RESULTS
predominated (Table 2).
The 60 consecutive patients in this study who sustained a combined ACL-MCL injury were involved in 1 of 18 different athletic activities at the time of injury (Table 1). Sixtytwo percent were participating in football (37%) or basket-
Four medial meniscal tears were recognized during arthroscopy in Group I patients (11% incidence). These medial tears were all located peripherally and all occurred in association with lateral meniscal tears. Two patients in Group II had a peripheral medial meniscal injury identified during
476 TABLE 2 Lateral meniscal tears in acute ACL deficient knees with MCL
injury
acute athletic knee injuries, the unhappy triad has a 25% incidence rate. In his original report&dquo; detailing 22 patients with combined ACL-MCL injury, 17 had medial meniscus
tears, described
° No management b
required.
Repairable. TABLE 3
Comparison of meniscal trauma between Groups I and II
either
or ruptured; there and three knees without meniscus damage. Cerabona et a1.3 grossly inspected 35 patients for evidence of meniscal abnormalities at the time of ACL repair. They found 31% had medial tears while 20% had a torn lateral meniscus; one patient had tears of both menisci. In contrast, Lucie et al. 13 reported only four medial and two lateral meniscal tears in 21 patients with acute, combined knee ligament injuries. All of the knee injuries reported by these surgeons~> ~3, 2o were managed by anterior knee arthrotomy; none were studied exclusively by arthroswere
as
loose, detached,
two lateral meniscal tears
copy.
In speaking with those who deal with athletic injuries on routine basis, popular acknowledgement of the &dquo;terrible triad&dquo; is evident. Indeed, recent review articleS21, 11 continue to proclaim its frequent occurrence, and current orthopaedic textbooks, including those limited to sports medicine and knee surgery, devote considerable discussion to the combined ACL-MCL-medial meniscus injury.4,6, 11, 12 Based upon the wide recognition of this triad by professional, paraprofessional, and lay persons alike, the natural assumption is that combined ACL-MCL-medial meniscus tears are indeed common athletic injuries. However, since the advent of arthroscopy as a primary tool for evaluation and treatment of knee injuries (circa 1975), studies have shown that lateral meniscal tears outnumber medial meniscal tears by a ratio of approximately 2:1 in patients with acute ACL disruption.5, 15, 17 In our practice, we have relied heavily on arthroscopy in the treatment of knee injuries. We recently summarized our arthroscopic findings regarding meniscal status at the time of surgical reconstruction in 336 patients with &dquo;acute&dquo; cruciate insufficiency.23 Of these, 33% (111) had no meniscal trauma, while 31% (104) had lateral and 18% (60) had medial meniscus tears; both menisci were torn in the remaining 18% (61) of these knees. As we gained clinical experience, it became apparent that historical perspectives regarding the frequency of medial meniscus abnormality in the face of combined ligamentous injury were erroneous, and the impetus for the current study came forth. By carefully screening these 60 patients in this study to make certain that all had sustained the combined injury in a single traumatic event, we hoped to avoid contamination of the data by accumulated meniscal and chondral trauma, which have been associated with episodic instability. z, 17 Therefore, all patients who incurred injury more than 30 days before knee arthroscopy and ACL reconstruction were excluded from the study, as were persons who had experienced previous trauma to the same knee, or reported significant reinjury (giving way, repeat effusion) following the a
a
b
Significant at the P < Significant at the P
O’Donoghue triad
revisited
Combined knee injuries involving anterior cruciate and medial collateral ligament tears K. DONALD
SHELBOURNE,* MD, AND PAUL A. NITZ, MD
From the Methodist
Sports Medicine Center, Indianapolis, "protect" joint surfaces,
ABSTRACT
most
We identified 60 consecutive patients with combined anterior cruciate and medial collateral ligament (ACLMCL) disruptions that were incurred during athletic endeavors. Each underwent acute reconstruction of the ACL. The arthroscopic data obtained at the time of reconstructive surgery was reviewed in order to determine the incidence of O’Donoghue’s triad (the "unhappy triad"), consisting of ACL, MCL, and medial meniscus
with these injuries absence of further
patients
demonstrate
commonly abnormality (meniscal
intraarticular
an
or
chondral).
In his landmark 1936 monograph, Campbell’ described a &dquo;combination&dquo; knee injury involving disruption of both the anterior cruciate and medial collateral ligaments (MCL), along with a tear of the medial meniscus. He further documented the occurrence of this constellation of findings in his article on ligament reconstruction in 1939.1 O’Donoghue’s publications during the 1950s18-2o regarding athletic knee trauma renewed awareness of such injury combinations-they gained wide recognition among physicians, coaches, and athletic trainers. Across the country, the association of ACL, MCL, and medial meniscus tears became known as the O’Donoghue triad.12, 1 Today, the &dquo;unhappy triad&dquo; is broadly acknowledged; the natural assumption follows that this type of injury occurs frequently. Based on our clinical impression, gained from extensive experience with athletic knee injuries, we began to question whether the widespread familiarity with the terrible triad correlated with the frequency of its occurrence. Accordingly, we retrospectively examined the records of 60 consecutive patients over a 6 year period who suffered ACL-MCL disruptions during athletic participation. All patients underwent arthroscopy and ACL reconstruction by the senior author (KDS). Surgery was performed in the acute postinjury phase (30 days or less postoperatively), without intervening attempts to fully rehabilitate patients and return them to competitive athletics. In this way we could reasonably expect the data to reflect the actual consequences of the index injury. We focused our attention on intraarticular abnormalities revealed by arthroscopy, and evaluated results by comparing patients with an incomplete (second-degree) MCL injury to those with a third-degree tear. It was not our intent to analyze the possible mechanism
tears. Patients were subdivided into two groups for analysis based upon the degree of MCL injury at time of presentation (Group I, 35 patients with a second-degree sprain; Group II, 25 patients with a complete, or thirddegree injury). Medial meniscus tears were an uncommon finding. Lateral meniscus tears significantly outnumbered medial meniscus tears in both groups, occurring in 25 (71 %) of GroupI patients and 8 (32%) of those in Group II. Even chondral fractures of the lateral femoral condyle outnumbered medial meniscus tears [6 (17%) versus 4 (11 %)] in patients with a seconddegree MCL sprain. Furthermore, when present in GroupI patients, tears of the medial meniscus were associated with a concomitant lateral meniscus injury. Group II patients were more likely (60%) than GroupI not to have any meniscal abnormality at all. We conclude that the classic O’Donoghue triad is, in fact, an unusual clinical entity among athletes with knee injuries; it might be more accurately described as a triad consisting of ACL, MCL, and lateral meniscus tears. This injury combination appears to be more common when an incomplete, or second-degree, tear of the medial collateral has occurred. Third-degree MCL injuries in conjunction with ACL disruptions seem to *
Address correspondence and reprnt requests to. K Donald Shelbourne, MD, Methodist Sports Medicme Center, 1815 N Capitol Avenue, Suite 530,
Indianapolis,
as
Indiana
IN 46202. 474
475
of injury, but rather to summarize the arthroscopic findings and share our observations in this group of injured athletes.
TABLE 1
Activity associated with index knee injury ___
MATERIALS AND METHODS
Sixty patients (49 men and 11 women) seen at the Methodist Sports Medicine Center between January 1983 and April 1989 were included in the study. Those in the study population represent a subset (17%) of 350 patients from our practice who were treated for acute ACL insufficiency during the same period of time. This percentage is consistent with previous reports&dquo;> 17, z2 regarding the number of patients with combined ACL-MCL injuries in relationship to total cases of anterior cruciate injury. As such, these 60 individuals comprise a large, representative group of consecutive patients sustaining a combined, acute ligamentous injury (ACL and MCL) during athletic participation. Each patient underwent arthroscopy and ACL reconstruction within 30 days (range, 1 to 28) following the date of original injury. There was no history of antecedent knee trauma in any patient, nor were any episodes of trauma or instability documented subsequent to the index injury (i.e., prior to surgical management). ACL injury was diagnosed by demonstration of positive Lachman and flexion rotation drawer tests at the time of initial clinical assessment. Examination in the operating room following induction of general anesthesia confirmed initial clinical impressions in all cases. For comparative purposes, patients were divided into two groups based upon the degree of MCL injury. Second-degree MCL injuries (35 patients) were defined as those with medial joint line opening (&dquo;gaping&dquo;) 5 to 10 mm greater than the contralateral knee upon application of a valgus stress with the knee flexed to 30° (Group I). Third-degree collateral injuries (25 patients) had greater than 10 mm of medial joint line opening compared to the uninjured knee on valgus stress, with absence of a clear endpoint to the stress examination (Group II). Grading of the MCL injury was determined by the senior author at the time of initial office assessment; examination was repeated in the operating room with the patient under general anesthesia. All intraarticular injuries were recorded following arthroscopic assessment of the injured knee. Specifically, the presence, location, and type of each meniscal tear and chondral injury were noted. For clarification, only tears through the cartilaginous substance of the meniscus were tabulated; meniscocapsular tears were not included. Data were stored on a computer and comparative results from Groups I and II were analyzed statistically using P values to determine the presence of significant differences.
°b Hockey, pole vaulting, ballet. Frisbee, badminton, water skiing, baseball, volleyball, kicked by a bull.
Figure 1. GroupI distribution of meniscal tears. Note: The first group (32%) are isolated lateral tears; the second group (8%) are isolated medial tears. ball (25% ). Second-degree and third-degree medial collateral injuries were nearly evenly distributed between these two
sports. Acute chondral fractures were found in 8 of the 35 (23%) patients in Group I and 3 of the 25 (12%) patients in Group II. Lateral femoral condyle injuries were found in six (17%) patients in Group I, whereas only two (8%) patients in Group II sustained a similar injury. No medial condylar fractures were recognized in either group. Two patients (6%) in Group I sustained a lateral tibial spine fracture as part of the injury complex; these fractures were associated with meniscal abnormality. Twenty-five patients (71% ) in Group I had a total of 28 acute lateral meniscal tears at the time of arthroscopy (Fig. 1). These tears were classified as one of four types: posterior horn avulsion, peripheral lateral meniscal tear, bucket-handle tear, or radial oblique tear. Three patients had a posterior horn avulsion of the lateral meniscus in addition to a radial tear. Radial oblique tears nearly outnumbered all other types of lateral meniscus tears combined for patients with a second-degree MCL injury (Table 2). Eight Group II patients sustained one of the four types of lateral meniscal tears (32% incidence); no single type of tear
oblique
RESULTS
predominated (Table 2).
The 60 consecutive patients in this study who sustained a combined ACL-MCL injury were involved in 1 of 18 different athletic activities at the time of injury (Table 1). Sixtytwo percent were participating in football (37%) or basket-
Four medial meniscal tears were recognized during arthroscopy in Group I patients (11% incidence). These medial tears were all located peripherally and all occurred in association with lateral meniscal tears. Two patients in Group II had a peripheral medial meniscal injury identified during
476 TABLE 2 Lateral meniscal tears in acute ACL deficient knees with MCL
injury
acute athletic knee injuries, the unhappy triad has a 25% incidence rate. In his original report&dquo; detailing 22 patients with combined ACL-MCL injury, 17 had medial meniscus
tears, described
° No management b
required.
Repairable. TABLE 3
Comparison of meniscal trauma between Groups I and II
either
or ruptured; there and three knees without meniscus damage. Cerabona et a1.3 grossly inspected 35 patients for evidence of meniscal abnormalities at the time of ACL repair. They found 31% had medial tears while 20% had a torn lateral meniscus; one patient had tears of both menisci. In contrast, Lucie et al. 13 reported only four medial and two lateral meniscal tears in 21 patients with acute, combined knee ligament injuries. All of the knee injuries reported by these surgeons~> ~3, 2o were managed by anterior knee arthrotomy; none were studied exclusively by arthroswere
as
loose, detached,
two lateral meniscal tears
copy.
In speaking with those who deal with athletic injuries on routine basis, popular acknowledgement of the &dquo;terrible triad&dquo; is evident. Indeed, recent review articleS21, 11 continue to proclaim its frequent occurrence, and current orthopaedic textbooks, including those limited to sports medicine and knee surgery, devote considerable discussion to the combined ACL-MCL-medial meniscus injury.4,6, 11, 12 Based upon the wide recognition of this triad by professional, paraprofessional, and lay persons alike, the natural assumption is that combined ACL-MCL-medial meniscus tears are indeed common athletic injuries. However, since the advent of arthroscopy as a primary tool for evaluation and treatment of knee injuries (circa 1975), studies have shown that lateral meniscal tears outnumber medial meniscal tears by a ratio of approximately 2:1 in patients with acute ACL disruption.5, 15, 17 In our practice, we have relied heavily on arthroscopy in the treatment of knee injuries. We recently summarized our arthroscopic findings regarding meniscal status at the time of surgical reconstruction in 336 patients with &dquo;acute&dquo; cruciate insufficiency.23 Of these, 33% (111) had no meniscal trauma, while 31% (104) had lateral and 18% (60) had medial meniscus tears; both menisci were torn in the remaining 18% (61) of these knees. As we gained clinical experience, it became apparent that historical perspectives regarding the frequency of medial meniscus abnormality in the face of combined ligamentous injury were erroneous, and the impetus for the current study came forth. By carefully screening these 60 patients in this study to make certain that all had sustained the combined injury in a single traumatic event, we hoped to avoid contamination of the data by accumulated meniscal and chondral trauma, which have been associated with episodic instability. z, 17 Therefore, all patients who incurred injury more than 30 days before knee arthroscopy and ACL reconstruction were excluded from the study, as were persons who had experienced previous trauma to the same knee, or reported significant reinjury (giving way, repeat effusion) following the a
a
b
Significant at the P < Significant at the P
