One adolescent (PN 2) had a right knee MRI and CT scan before to presentation in the orthopedic clinic. The CT and MRI series are depicted in Figure 2.
All patients underwent primary surgical correction via a medial hemiepiphysiodesis with insertion of a medial tension band plate for guided growth and gradual correction of the deformity. Serial examinations and standing alignment films were performed post-surgery. Radiographs were re-evaluated until restoration of a normal mechanical axis. Two patients responded well to guided growth with restoration of their mechanical axis (PN1,3). One limb malalignment failed to correct and the patient underwent removal of the medial tension band plate and a lateral opening distal femoral osteotomy (PN 2). The authors postulate that the reason for the failure of guided growth in PN2 was his more advanced bone age (15 years) compared with PN1 (14.5 years) and PN3 (13.5 years) on left-hand radiographs (Table 2). However, at that time, the senior author discussed treatment options with the family with the knowledge that the patient may not have enough growth remaining and may need an osteotomy in the future if the less invasive option (guided growth) failed. All adolescents returned to competitive soccer. Presenting and follow-up standing alignment radiographs for all patients are depicted in Figures 3–5.
The distal femoral physis serves as the primary location of endochondral ossification and provides the largest contribution to longitudinal growth of the lower extremity.4 Repetitive microtrauma can lead to disruption of the metaphyseal vasculature that supplies the physis with necessary substrates to promote normal endochondral ossification.5 Without appropriate perfusion, further ossification is halted, causing chondrocytes to accumulate in the proliferative zone and form long columns of hypertrophic cartilage.5 Radiographically, this can be seen as focal widening of the physis. This aberrancy is often temporary; however, if there is significant ischemia, osseous necrosis may ensue, leading to permanent growth disturbances as highlighted in this case series.6
There have been few cases of distal femoral physeal injuries in the literature, typically from trauma or resulting from fracture. A case report by Holloway et al.7 described a similar injury pattern in a 16-year-old soccer player who developed an asymmetric genu valgum deformity from a Salter-Harris V injury to the lateral distal femoral physis after an medial collateral ligament (MCL) injury. The patient was ultimately treated successfully using a distal femoral osteotomy.7 To our knowledge, this is the first report of a series of adolescents with lateral distal femoral hemiepiphyseal growth arrest leading to a significant limb deformity with the need for subsequent surgical correction.
The diagnosis of lateral distal femoral hemiphyseal arrest is complex because many other conditions may lead to a similar deformity or symptoms. Genu valgum deformities in children may be caused by congenital hip conditions such as coxa vara, acute trauma to the lateral femoral physis, increased body mass index, and metabolic conditions, none of which were present in our patients.8-11 In our study, the key diagnostic imaging finding was the appearance of a widened irregular physis. Laor et al.12 detailed the imaging findings of hemiepiphyseal widening of the distal femoral physis on MRI in six children who all participated in competitive sports. Interestingly, in their study, only one child presented with a deformity and none required surgical intervention.
Our study further demonstrates that overuse injuries in the growing child can cause significant long-term problems. We believe that the mechanism for lateral distal femoral growth arrest stems from repetitive valgus stress due to kicking a soccer ball or football, causing repetitive compression and damaging of the lateral physis. It is imperative that sports physicians, parents, coaches, and players be aware of the risk factors and signs of overuse to prevent chronic physeal injuries. These signs include both intrinsic and extrinsic factors that increase the risks as well as the potential for long-term consequences of injury. Intrinsic factors include age, body mass index, gender, and anatomic variations. Extrinsic factors reflect the type of athlete, and duration and intensity of training.13 These extrinsic factors should be addressed when assessing patients with suspected overuse injuries as well as those presenting for preparticipation physicals. Rapid increase in training load after long periods of inactivity, athletes performing at levels higher than their level of training, and those with consistent high-level sport activity (eg, those participating in sports year-round) with or without the presence of a professional coach are particularly prone to overuse injuries.14 The patients described in this report were at risk given their year-round participation in sports, high-intensity training, and skeletal immaturity.
In summary, chronic overuse injuries are an incredibly common sports injury, and in the skeletally immature, can lead to permanent growth disturbances that may necessitate surgical intervention. Overuse injuries can be avoided by modifying factors that put the young athlete at risk and intervene before the onset of permanent sequelae.
1. Dalton SE: Overuse injuries in adolescent athletes. Sports Med 1992;13:58-70.
2. Shaw N, Erickson C, Bryant SJ, et al.: Regenerative medicine approaches for the treatment of pediatric physeal injuries. Tissue Eng B Rev 2018;24:85-97.
3. Stevens PM, MacWilliams B, Mohr RA: Gait analysis of stapling for genu valgum. J Pediatr Orthop 2004;24:70-74.
4. Birch JG, Makarov MA, Jackson TJ, Jo CH: Comparison of anderson-green growth-remaining graphs and white-Menelaus predictions of growth remaining in the distal femoral and proximal tibial physes. JBJS 2019;101:1016-1022.
5. Apte SS, Kenwright J: Physeal distraction and cell proliferation in the growth plate. J Bone Joint Surg Br 1994;76:837-843.
6. Caine D, DiFiori J, Maffulli N: Physeal injuries in children's and youth sports: Reasons for concern? Br J Sports Med 2006;40:749-760.
7. Holloway E, Sutton P, Cooper R: An unusual cause of genu valgum and persistent instability. J Surg Case Rep 2017;2017:rjx166.
8. Shim JS, Kim HT, Mubarak SJ, Wenger DR: Genu valgum in children with coxa vara resulting from hip disease. J Pediatr Orthop 1997;17:225-229.
9. McCarthy JJ, Kim DH, Eilert RE: Posttraumatic genu valgum: Operative versus nonoperative treatment. J Pediatr Orthop 1998;18:518-521.
10. Zhang AL, Exner GU, Wenger DR: Progressive genu valgum resulting from idiopathic lateral distal femoral physeal growth suppression in adolescents. J Pediatr Orthop 2008;28:752-756.
11. Espandar R, Mortazavi SM, Baghdadi T: Angular deformities of the lower limb in children. Asian J Sports Med 2010;1:46-53.
12. Laor T, Wall EJ, Vu LP: Physeal widening in the knee due to stress injury in child athletes. AJR Am J Roentgenol 2006;186:1260-1264.
13. McGuine T: Sports injuries in high school athletes: A review of injury-risk and injury-prevention research. Clin J Sport Med 2006;16:488-499.
Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.
14. Hogan KA, Gross RH: Overuse injuries in pediatric athletes. Orthop Clin North Am 2003;34:405-415.