PFATS Articles
Acute Subluxation of the Proximal Tibiofibular Joint
Scott C Trulock, MA, ATC Denver Broncos Football Team Denver, CO
OBJECTIVE:
In football, as in all sports, injuries to the knee joint are well documented as to their mechanism of injury, evaluation, diagnosis, treatment, and rehabilitation. Physicians and athletic trainers are well educated in assessing such knee injuries and designing a plan for recovery. However, the proximal tibiofibular joint occasionally sustains injury that can be difficult to evaluate and diagnose. The literature is limited in regard to injuries involving this joint. The proximal tibiofibular joint presents unique biomechanical characteristics, as it is directly affected by stresses in both the knee and ankle joints. Instabilities involving the proximal tibiofibular joint can either be chronic or acute. Evaluation and diagnosis can further be complicated by the variety of other tissues in close proximity to the joint, including the tendon of the biceps femoris, the lateral collateral ligament and the lateral meniscus. The course of treatment following injury includes a wide range of options. Depending on the specifics of the trauma sustained, the athlete may recover with a period of rest and rehabilitation, or may require reconstructive surgery.
BACKGROUND:
As described in the literature, most injuries involving the proximal tibiofibular joint are the result of either high energy torsion stresses upon the knee or direct contact to the head of the fibula. This case involves a 26 year-old professional football player injured in a collision with several other players while attempting a block on the kickoff return team during a game. The athlete was injured when a group of other players fell into him as he was making the block. The etiology of this injury was attained by both the personal account of the athlete as well as review of the game tape. His knee sustained both a direct blow to the lateral aspect of the knee as well as a torsion stress while in a flexed position with his foot planted and bearing weight. In order to fully understand the biomechanical issues of this injury, a brief review of anatomy is helpful.
ANATOMY:
The proximal head of the fibula articulates with the proximal tibia on the posterior-lateral surface just distal to the knee joint. The articulating surfaces are relatively shallow and therefore, the joint relies on soft tissue for stabilization. The joint capsule is supported by both anterior and posterior ligamentous attachments. Other structures that aid in preventing anterior and posterior translation of the fibula include the popliteus tendon, the lateral collateral ligament, the arcuate ligament, fabellofibular ligament, poplitieofibular ligament, and the popliteus muscle. In addition, the tendon of the biceps femoris attaches to the head of the fibula and aids in stability of the joint. Stability provided by these structures vary depending on the point within the range of motion of the knee. The lateral collateral ligament is taut from 0 to about 30 degrees of flexion. As the knee moves further into flexion, the head of the fibula translates anteriorly as the lateral collateral ligament relaxes along with the lessening force supplied by the tendon of the biceps femoris. This loss of force supplied by these structures when the knee moves into flexion results in the increase susceptibility to injury of the proximal tibiofibular joint. Close association is also maintained between the proximal tibiofibular joint and the distal tibiofibular joint near the ankle. As the ankle dorsiflexes, the fibula is allowed to externally rotate. If dorsiflexion generates forces that cannot be sustained as normal fibular rotation, a posterior or superior translation injury could occur to the proximal tibiofibular joint.
The literature describes three types of dislocation injuries to the proximal tibiofibular joint: anterolateral, posteromedial, and superior. The anterolateral dislocation is the most common and usually occurs from either a fall on a hyperflexed knee with the foot inverted and plantar flexed, or from a torsion stress on a weight-bearing flexed knee. With the lateral collateral ligament and the biceps femoris relaxed, the plantar flexed foot enables the anterior lower leg muscles to force the fibula anteriorly. The posteromedial dislocation can occur when the head of the fibula sustains a direct blow, forcing the fibula medially and posteriorly. A violent contraction of the biceps femoris can contribute to the posteromedial dislocation. A superior dislocation of the fibula can occur with a simultaneous severe ankle sprain and superior translation of the fibula. In many of these cases, the interosseous membrane is compromised. Any of the injuries may involve other structures, including a sprain of the lateral collateral ligament or a fracture of the fibula.
Evaluation of an injury to the proximal tibiofibular joint can reveal specific signs and symptoms. Pain and localized swelling around the head of the fibula are common. Weight bearing might also elicit pain. In addition to pain with knee motion, the athlete may not be able to fully extend the knee. Ankle motion very often will aggravate the knee pain. Due to its close proximity, transient peroneal nerve symptoms might also be present. Clicking or popping around the proximal tibiofibular joint might also be reported by the athlete with either knee or ankle motion. Stress testing the joint by manual anterior and posterior translation may elicit laxity, pain, or crepitus. Obviously, some of these symptoms are closely related to injuries involving other structures of the lateral knee including the lateral collateral ligament, the lateral meniscus, and the biceps femoris tendon.
ASSESSMENT:
The case involving the player at issue is consistent with the existing literature. A defensive cornerback by position, the player was 73 inches tall and 201 pounds in his fourth year of professional football at the time of injury. He had no history of injury to the right lower extremity. Five years prior, the player sustained a distal fibular fracture on the contralateral side. No symptoms were reported prior to the current injury. As stated by the player and confirmed through film review, the player was attempting a block when several other players fell into him. Due to the number of players involved in the collision, the amount of direct contact to the lateral aspect of the knee was difficult to determine. His body was forced to rotate away from his planted right foot with the knee in a flexed position, creating a torsion stress on the right knee. As the player attempted to ambulate himself from the field, he was assisted by the athletic training staff to the sideline and examined by the team physician. He denied hearing a pop but had immediate pain and difficulty bearing weight on the affected extremity. He was examined on the bench and had tenderness over the proximal tibiofibular joint with discernable crepitus and increased translation causing pain. Radiographs were negative for a fracture or displaced dislocation. Neurologic examination was normal. The player was removed from competition, iced and rested overnight. He was instructed in the use of crutches for non-weight bearing ambulation on the affected extremity. Examination by the physician on the following day revealed symptoms consistent with the original impression. The athlete was tender to palpation over the proximal tibiofibular joint. Knee range of motion was 10 to 130 degrees with pain localized to the posterolateral aspect of the knee. Cruciate ligament tests as well as medial collateral stress tests were negative. The athlete reported pain with varus stress test, but no increased opening at 0 and 30 degrees was identified by the physician. The physician also identified notable increased translation with stress testing in the proximal tibiofibular joint when compared to the opposite side. The athlete also described continued pain and crepitus with the translation testing. He also had pain with forced flexion and external rotation localized to the proximal tibiofibular joint. Stress testing for the posterolateral corner at 30 and 90 degrees was difficult to assess due to pain. Neurologic and motor exam continued to be normal, except for the peroneal group remaining at 4/5 secondary to pain. An MRI was scheduled for later that day.
MRI results confirmed the physician�s clinical diagnosis of a complete capsular disruption and interosseous ligament tearing along the anterior and superior margins of the proximal tibiofibular joint. The posterolateral capsule displayed signal of a mild sprain, but was otherwise intact. In addition, a small contusion of the anterolateral tibial plateau was noted.
REHABILITATION
Recovery required about 10 weeks of rest and rehabilitation. The athlete was instructed to remain non-weight bearing for four weeks. During this period, the knee was treated with ice daily and subjected to minimal activity. Per physician instructions, the athlete began partial weight bearing and light rehabilitation after four weeks. The rehabilitation protocol included active knee range of motion in the pool, straight leg raises with the foot plantar flexed, shallow squats, and stationary bike. After five weeks, the athlete was instructed to gradually work to full weight bearing. Exercises introduced during this period included pool walking and balance training. After six weeks the athlete was examined by the physician and demonstrated full pain free range of motion with resistance. Stress testing revealed that the proximal tibiofibular joint was stable. The physician cleared the athlete to continue with slow, gradual progression back to full activity as symptoms allowed. Following the exam, new exercises were introduced. These included resisted ankle exercises, resisted leg press, stair climbing, core exercises, and manually resisted hip PNF patterns. The athlete was able to run eight weeks from the time of injury. As the team entered the off-season, a conservative approach was implemented for the remainder of the rehabilitative process. Football related activities were delayed until the start of off-season conditioning, four months from the time of injury.
KEY POINTS:
The proximal tibiofibular joint presents a unique addition to the evaluation of any knee or ankle injury. Its subtle motions accompany normal function of both the knee and ankle joints. Although injury to this joint is rare, accurate evaluation and diagnosis is critical to enable a full recovery. In this case, identification was made easier by the fact that the disruption of the proximal tibiofibular joint was relatively isolated. In many cases involving the proximal tibiofibular joint, the lateral collateral ligament, the posterolateral corner, or the biceps femoris tendon sustain trauma as well. As with any injury, accurate etiology is most helpful in establishing a clinical impression. Results from an MRI can give the best assessment on involved tissue damage, thus ruling out injury to structures that have not been traumatized.
CLINICAL APPLICATION:
The rehabilitation process following an injury to the proximal tibiofibular joint dictates specific indications and contraindications. Once the injury has been evaluated and diagnosed by a physician, an appropriate course of action can be set. For an acute subluxation injury, the athlete should be placed on crutches and instructed to limit any knee or ankle activity. The use of a knee immobilization device may not be necessary but could be useful in some circumstances. Following several weeks, light range of motion activities may be started as directed by the physician. Careful attention should be paid by the athletic trainer to monitor any signs or symptoms including pain, swelling, or crepitus. As the athlete is able to tolerate increased activity, exercises can be added gradually building to functional drills. Care should be taken to avoid exercises which require strong contraction of the hamstring group, due to the attachment of the biceps femoris tendon on the head of the fibula. Also, early exercises should not include any forced ankle dorsiflexion
This case represented an isolated injury that required a simple and conservative rehabilitation plan. Trauma to the proximal tibiofibular joint can be more severe and require additional medical care. In younger children, the proximal tibiofibular joint can chronically sublux and require therapy and modified activity. Chronic subluxation in adults may require surgical intervention involving reconstruction of the joint. Acute dislocations will require reduction as well as possible reconstruction if the condition becomes chronic. Each of these cases would require a varied rehabilitation protocol.
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