This article is more than 5 years old. Information may no longer be current.
An adolescent with acute, atraumatic knee pain while playing basketball
Click Here to Manage Email Alerts
A 13-year-old male patient presented approximately 2 weeks after he sustained an atraumatic, left knee injury while playing basketball. The injury occurred when the patient was pivoting and shooting. He was unable to precisely identify when he first felt a pop within his knee. The patient developed acute left knee swelling. Although able to tolerate weight-bearing, he had discomfort and felt an occasional clunk with knee flexion/extension. The pain was predominantly described as involving the lateral aspect of the knee. He was initially seen at an urgent care facility in the days following his injury and was then seen by a local orthopedic surgeon before he presented to our clinic for second opinion.
The patient’s medical history was negative for chronic medical conditions. Five years prior to presentation, he underwent a left knee arthroscopic irrigation and debridement for suspected acute septic arthritis but had no subsequent evidence of infection or apparent left knee sequela in the intervening years. The patient took no chronic home medications nor endorsed any known drug allergies. He lived with his parents and was active playing recreational and organized sports, including basketball.
On physical examination, the patient’s vital signs were normal. Focused examination of the left knee was performed. Inspection revealed a joint without gross deformity. The portal sites from the prior arthroscopy were difficult to identify. The patient’s skin was otherwise without lesions, wounds, ecchymosis or erythema. On palpation, the joint had 2+ effusion, but was not appreciably warm compared to the uninjured, contralateral knee. Ligamentous testing was negative for laxity or pain with stress of the ACL, PCL, medial collateral ligament and lateral collateral ligament. Provocative meniscal testing was equivocal. There was some tenderness to palpation along the lateral joint line. A firm, mobile mass was palpated in the suprapatellar pouch.
Source: Christopher C. Dodson, MD
Review of a 1.5 Tesla MRI study done without IV or intra-articular contrast demonstrated a skeletally immature left knee with no obvious abnormality of the distal femoral or proximal tibial physes. There was no evidence of sequestrum, involucrum, abscess or other radiographic sequela of his reported history of remote, suspected septic arthritis. The cruciate and collateral ligaments were within normal limits. There was no evidence of injury to the medial or lateral menisci.
A complex effusion consistent with hemarthrosis was seen. A 3.6-cm wide, 2-cm deep and 0.4-cm high loose body was noted in the lateral aspect of the suprapatellar pouch. A corresponding cartilaginous defect with underlying marrow edema was seen in the anterior aspect of the lateral femoral condyle. Marrow edema was also noted in the anterior tibial epiphysis consistent with a hyperextension injury (Figure 1).
What is your diagnosis?
See answer on next page.
Acute osteochondral fracture of the lateral femoral condyle of the knee
Given the age of the patient, the size of the osteochondral defect, the mechanical symptoms of the large, loose fragment and the likelihood of accelerated degenerative change if the fracture was left untreated, surgery was recommended. The patient and his parents agreed with this course. At an outpatient surgery center, the patient was put under general anesthesia with a femoral nerve block for diagnostic arthroscopy and open osteochondral fragment repair. Standard inferolateral and inferomedial portals were established to facilitate a thorough evaluation of the joint.
The ACL, PCL and menisci were noted to be without injury. A large osteochondral defect was identified on the anterior aspect of the lateral femoral condyle and the corresponding loose chondral fragment was encountered in the lateral aspect of the suprapatellar pouch. No other chondral injuries were observed. Under direct visualization, the loose fragment was removed arthroscopically and wrapped in antibiotic-impregnated saline-soaked gauze while the surgeon focused on exposure of the chondral defect. The inferolateral portal was extended from the mid-pole of the patella to just proximal to the lateral meniscus to fully expose the chondral defect on the lateral femoral condyle. The defect was debrided to well-shouldered edges with curettes and microfracture of the underlying subchondral surface was performed with excellent bleeding noted. The fragment was reduced into anatomic position and provisionally fixed with K-wires. Three 1-mm, poly-L lactide acid compression screws were used for definitive fixation of the fragment. The surgical site was thoroughly irrigated and closed (Figure 2).
A hinged knee brace was applied. The patient was prescribed a continuous passive motion machine to prevent stiffness and he remained non-weight-bearing for the first 6 weeks postoperatively. Weight-bearing progressed to full weight-bearing during a 2-week period. At last follow-up, the patient was ambulating without pain, discomfort or other symptoms. An MRI will be obtained prior to his next follow-up to assess the status of the repair.
The patient sustained a large, traumatic osteochondral fracture of the lateral femoral condyle from a likely hyperextension mechanism while playing basketball. Hyperextension is one possible mechanism for osteochondral fractures of the knee. External rotation of the tibia, such as occurs during the pivot-shift implicated in ACL injury, has also been implicated. Osteochondral fractures reportedly occur in as many as half of all traumatic patellar dislocations.
Advanced imaging, such as MRI, can be critical to accurately diagnose these injuries. Lesions may vary in size from small focal injuries to the large fragment seen in this case. Smaller lesions may be missed on plain radiographs. Delayed diagnosis in the absence of advanced imaging has been associated in the literature with a resultant delay in care. Osteochondral fracture should remain on the differential diagnosis for any traumatic knee injury, particularly when significant effusion may limit thorough examination. The accompanying threshold for advanced imaging should be low.
Although osteochondral injury can occur in patients of any age, the highest incidence is in individuals about 20-years-old who have calcification of the tidemark, due to its effect on the interface between articular cartilage and the underlying subchondral bone. However, younger age, particularly in conjunction with open physes as in the case of this patient, as well as a smaller-sized lesion, appear to be of positive prognostic benefit to the success of chondral repair.
Treatment strategies depend on size of the lesion and the presence of concomitant pathology and include removal of the fragment without repair/fixation, reduction and fragment repair/fixation or regenerative procedures, such as microfracture or autologous chondrocyte implantation. In this case, given the size of the fragment, age of the patient and acuity of the injury, reduction and fixation with bioabsorbable implants was performed.
There is some evidence to suggest a period of non-weight-bearing following large or severe osteochondral injury may prevent further injury with additional subchondral collapse and subsequent degenerative change.
There remains substantial opportunity for further research to optimize management of these fractures to reduce long-term sequelae and degenerative change.
- References:
- Kennedy JC, et al. J Bone Joint Surg Br. 1966;436–440.
- Kühle J, et al. Int Orthop. 2013;doi:10.1007/s00264-013-2070-7.
- Lüthje P, et al. Acta Orthop Belg. 2008;74:249-254.
- Nakamae, A, et al. Knee Surg Sports Traumatol Arthrosc. 2006;doi:10.1007/s00167-006-0087-9.
- Nomura E, et al. Arthroscopy. 2003;19:717-721.
- For more information:
- Michael C. Ciccotti, MD, and Christopher C. Dodson, MD, can be reached at Rothman Institute at Thomas Jefferson University, 925 Chestnut St., 5th Floor, Philadelphia, PA 19107; email: michael.ciccotti@jefferson.edu; christopher.dodson@rothmaninstitute.com.
- Edited by Michael C. Ciccotti, MD, and Michael C. Fu, MD, MHS. Ciccotti is a chief resident in the department of orthopaedic surgery at Thomas Jefferson University and Rothman Institute and will be a sports medicine fellow at the Steadman Phillipon Research Institute following residency. Fu is a chief resident at Hospital for Special Surgery and will be a sports medicine and shoulder surgery fellow at Rush University Medical Center following residency. For information on submitting Orthopedics Today Grand Rounds cases, please email: orthopedics@healio.com.
Disclosures: Dodson reports he is a paid consultant for Arthrex. Ciccotti reports no relevant financial disclosures.