Older woman equestrian with a knee dislocation
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A 70-year-old woman presented to the ED after being kicked by her horse on the lateral side of her left knee. She experienced immediate severe left knee pain, which was accompanied by significant swelling, deformity and inability to ambulate.
On arrival to the ED by ambulance, she was noted to have an obvious dislocation of her left knee, which was promptly closed reduced under sedation by ED staff.
Source: Jonathan W. Cheah, MD
On physical exam after closed reduction of the left knee, the skin about her left knee was intact. There was a large knee effusion with bogginess, bruising and tenderness to palpation over her medial femoral condyle and medial joint line. Ligamentous exam was remarkable for a grade 2B Lachman test, positive posterior drawer test and obvious laxity on valgus stress test at 0° and 30° of knee flexion compared with the contralateral side. She was neurovascularly intact with palpable dorsalis pedis and posterior tibial pulses and an ankle brachial index (ABI) of 1.03 compared with 1.10 on the contralateral side.
Radiographic evaluation of the left knee demonstrated a reduced knee joint with a large avulsed cortical fragment off the medial femoral condyle and entrapped in the medial compartment of the knee (Figure 1). CT angiography was negative for vascular injury. MRI of the left knee revealed complete ACL and PCL tears and an avulsion fracture of the medial collateral ligament (MCL) off the medial femoral condyle that had flipped into the medial compartment of the knee with a large cortical fragment (Figure 2). The fibular collateral ligament, popliteus tendon, biceps femoris tendon and iliotibial band were intact.
The patient was initially immobilized in a long-leg splint and then transition to a hinged knee brace locked in extension for ease of patient mobilization. She was made non-weight-bearing given the entrapped cortical fragment within the medial compartment of her knee. The patient was discharged after all appropriate imaging was obtained and the surgical intervention was planned.
What are the best next steps in management of this patient?
See answer below.
MCL avulsion fracture repair
The patient was indicated for open repair of an MCL avulsion injury.
She was also indicated for possible second, staged cruciate ligament reconstruction after rehabilitation and recovery of knee range of motion (ROM) to retore stability and function of her knee if she had recurrent instability with nonoperative treatment of her cruciate injury.
Open repair of MCL avulsion injury
Examination under anesthesia was performed revealing a grade 2B Lachman, pivot shift (2+), normal varus stress test, valgus stress test (2+) at 0° flexion, valgus stress test (3+) at 30° flexion, anterior drawer (1+) and posterior drawer (1+).
A longitudinal incision was made from the medial epicondyle to the level of the joint line. Blunt dissection was performed down to the level of the sartorial fascia to protect the saphenous neurovascular structures. The proximal insertions of the MCL and posterior oblique ligament (POL) were found to be completely avulsed off the femoral origin and attached to a medial femoral condyle avulsion fracture that was incarcerated in the medial compartment of the knee.
The area of the femoral avulsion fracture was prepared for osteosynthesis using a freer elevator and rongeur. Four suture anchors were placed around the perimeter of the avulsion site for suture fixation and augmentation. Two 3-0 nylon sutures were used to control the avulsion fracture fragment. Sutures from the suture anchors were systematically placed through the avulsed fracture with the intact attached MCL and POL. The knee was placed in 30° flexion with a varus force, and these sutures were tensioned and tied in a posterior to anterior fashion.
Two K-wires were placed in the central portion of the now reduced fracture. Fluoroscopy was used to confirm the wires did not penetrate the intercondylar notch. These wires were then over-drilled and exchanged for two 3-mm headless compression screws to achieve satisfactory fixation of the fracture (Figure 3). The suture tails were then passed through the proximal overlying soft tissue stump, tensioned and tied down to reinforce the repair in a vest-over-pants fashion.
Repeat examination under anesthesia showed the patient maintained full knee extension and 135° flexion and valgus stability in full extension and 30° flexion was restored.
Postoperative rehabilitation
Postoperatively, the patient was placed in a hinged knee brace locked in full extension and made toe-touch weight-bearing. She began a physical therapy ROM protocol with passive ROM only for 6 weeks followed by progression to weight-bearing as tolerated (WBAT) and active ROM in the brace.
Despite work with a home physical therapist, the patient fell behind on knee ROM goals. An intra-articular corticosteroid injection was trialed to help with adhesions and pain during therapy, but the patient’s progress with therapy remained slow and she was only able to obtain knee ROM from 7° shy of full extension to 70° flexion.
Arthroscopic lysis of adhesion
Given her functional goals, the patient was indicated for arthroscopic lysis of adhesions (LOA) and manipulation under anesthesia (MUA) for arthrofibrosis of the knee 5 months after initial surgery.
Diagnostic knee arthroscopy demonstrated significant suprapatellar pouch scarring and limited patellar mobility. The ACL and PCL were abnormal with significant scarring to the anterior fat pad. A shaver was used to debride scar tissue in the suprapatellar pouch, the intercondylar notch, the anterior capsule and the medial and lateral parapatellar areas. Patellar mobility improved significantly after debridement.
After LOA, gentle manipulation of the knee was done to improve knee ROM from full extension to 115° flexion. Fluoroscopy helped confirm knee stability and the absence of an acute fracture.
Postoperatively, the patient was made WBAT, provided with a continuous passive motion machine and started on an aggressive physical therapy ROM protocol. About 2 months after LOA and MUA, she had full knee extension and knee flexion to 110°. She had excellent secondary stability of her knee with a grade 2B Lachman, posterior drawer (+1) and a knee that was stable to varus and valgus stress at 0° and 30° flexion. She was walking long distances without pain or symptoms of knee instability and has since returned to recreational equestrian riding.
Discussion
Acute knee dislocations are rare but potentially devastating injuries. Acute management of traumatic knee dislocations involves prompt reduction of the dislocated knee, evaluation for popliteal artery injury (ABIs, CT angiography, serial neurovascular examinations), immobilization and identification of injured structures. Identification of injured structures using physical exam maneuvers, radiographs, MRI and examination under anesthesia is imperative to planning repair, reconstruction and surgical timing. Overall, literature supports operative intervention with repair/reconstruction over nonoperative treatment with a period of immobilization followed by ROM in a brace. Nonoperative treatment remains a viable option in select patients, such as geriatric or inactive patients with significant medical comorbidities, as long as outcome expectations are addressed with the patient. Although the patient in this report was aged 70 years, she was physiologically younger, active and desired a functional outcome that was more likely to be achieved with operative intervention. Controversy remains regarding the optimal timing to proceed with surgical intervention. Acute reconstruction/repair, staged repair/reconstruction and delayed reconstruction each have advantages and disadvantages. Given the patient’s MCL avulsion and incarcerated cortical fracture fragment within the medial compartment of the knee, we elected for staged repair/reconstruction with expedited repair of extra-articular structures and, eventually, planned delayed reconstruction of cruciate ligaments if she had recurrent instability in her activities.
MCL avulsion fractures in the adult population are rare and only a few case reports have been published on this injury pattern. These injuries must be treated differently than typical mid-body tears. Of these reported cases, two had concomitant ACL and PCL tears, one was accompanied by an ACL tear and one occurred with a PCL tear. All cases were in young men who had sustained high-energy knee injuries. Prior case reports each described different techniques for repairing the MCL avulsion fracture to its femoral origin: repair with No. 1 Vicryl sutures, bone anchors and a spiked washer, and metal suture anchors placed in a double-row configuration.
Given the large size of the avulsed fracture fragment in our case, we elected to repair the MCL avulsion fracture using four suture anchors, two headless compression screws and overlying soft tissue reinforcement to maximize the stability of the repair.
While our patient’s MCL avulsion fracture healed uneventfully, she made slow progress with physical therapy and was unable to meet ROM goals due the development of arthrofibrosis. The development of arthrofibrosis after knee injury has been correlated with the severity of injury, as well as with acute surgical intervention and prolonged immobilization. Our patient wanted to exhaust nonoperative measures to regain her ROM, but after a trial of several months of intensive physical therapy, as well as intra-articular corticosteroid injection, she elected to under LOA and MUA. This resulted in a marked improvement in her knee ROM and she had good secondary stability of her knee without the need for cruciate reconstruction.
Key points
- MCL avulsion fractures are rare injuries in the adult population and typically occur secondary to high-energy knee injuries with concomitant cruciate tears.
- Combination of suture anchor and headless compression screws is an effective fixation strategy for MCL avulsion injuries with a large fracture fragment.
- Patients with severe multiligamentous knee injuries are at high risk for the development of arthrofibrosis even with staged repair/reconstruction and require aggressive physical therapy and close monitoring. LOA and MUA remain an effective treatment for those patients who have failed to reach their ROM goals.
- Select patients with multiligamentous knee injury can achieve good secondary knee stability that meets their activity goals without undergoing cruciate reconstruction.
- References:
- Albtoush OM, et al. Clin Imaging. 2019;doi:10.1016/j.clinimag.2018.09.006.
- Bodendorfer BM, et al. J Knee Surg. 2019;doi:10.1055/s-0038-1655741.
- Boyce RH, et al. J Am Acad Orthop Surg. 2015;doi:10.5435/JAAOS-D-14-00349.
- Cox CL, et al. N Am J Sports Phys Ther. 20083:198-203.
- Dedmond BT, et al. Am J Knee Surg. 2001;14:33-38.
- Guo D, et al. Medicine (Baltimore). 2019;doi:10.1097/MD.0000000000018376.
- Haddad S, et al. Surg J (NY). 2017;doi:10.1055/s-0037-1599256.
- Levy BA, et al. Arthroscopy. 2009;doi 10.1016/j.arthro.2009.01.008.
- Naik AM, et al. J Orthop Surg (Hong Kong). 2007;doi:10.1177/230949900701500117.
- Richter M, et al. Am J Sports Med. 2002;doi:10.1177/03635465020300051601.
- Wui J, et al. EFORT Open Rev. 2020;doi:10.1302/2058-5241.5.190012.
- For more information:
- Jonathan W. Cheah, MD, is in the department of orthopedic surgery at Santa Clara Valley Medical Center and an affiliated clinical assistant professor at Stanford University. He can be reached at 751 S. Bascom Ave., San Jose, CA, 95128; email: jonathan.cheah@hhs.sccgov.org.
- Mark E. Cinque, MD, MS; and Galvin J. Loughran, MD, an orthopedic surgery resident at Stanford Health Care, can be reached at Stanford Medicine, Department of Orthopaedic Surgery, 450 Broadway Ave., Redwood City, CA 94063. Cinque’s email: mec89@stanford.edu. Loughran’s email: gjl42@stanford.edu.
- Edited by Mark E. Cinque, MD, MS, and Filippo F. Romanelli, DO, MBA. Cinque is a chief resident in the department of orthopedic surgery at Stanford. He will pursue a fellowship in sports medicine at The Steadman Clinic/Steadman Philippon Research Institute following residency completion. His interest is in complex knee surgery and multiligament reconstruction. Romanelli is a chief orthopedic resident at Rutgers – Jersey City Medical Center with an interest in adult reconstruction. He will be at New York University for his fellowship. For information on submitting Orthopedics Today Grand Rounds cases, please email: orthopedics@healio.com.
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