Acute injuries to the posterolateral corner of the knee in children: a case series of 6 patients

Isolated femoral avulsion of the popliteus tendon: a systematic review of the literature

The popliteus tendon is an important part of the posterolateral corner of the knee. Isolated injuries to the posterolateral corner are very rare, as most injuries occur in multiligamentous knee trauma. Purely isolated popliteus tendon injuries are even more rare. There is very little evidence for treatment of isolated popliteus tendon avulsion injuries. The aim of this systematic review is to report on all publications regarding isolated popliteus tendon avulsion injuries and hopefully provide some guidance for future treatment algorithms. A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Studies were included if they documented isolated popliteus tendon avulsion injuries. Exclusion criteria were studies with popliteus injuries in combination with other knee ligamentous injuries and popliteus tendon injuries other than femoral avulsion injuries. Twenty-eight studies were included which mentioned in total 38 patients with isolated popliteus tendon avulsion injuries. 24 patients (63%) were treated operatively. 3 (8%) patients were diagnosed arthroscopically but did not receive any surgical treatment. 9 patients (24%) were treated conservatively. In two publications, there was no mention of treatment. We found no clear recommendations in the literature for treatment of this rare injury.

Adjustable-loop cortical suspension device for posterolateral corner reconstruction in the setting of fibular avulsion fracture: a case series and novel technique description

INTRODUCTION

A novel technique using an adjustable-loop cortical suspension toggle device for reduction of a fibular head avulsion fracture (arcuate fracture) in posterolateral corner (PLC) reconstruction is described. Results of clinical follow-up are presented.

MATERIALS AND METHODS

9 patients were retrospectively identified who underwent posterolateral corner reconstruction using an adjustable-loop cortical suspension toggle device. Radiographic examination was used to evaluate the successful healing of the avulsed fibular head fragments post-operatively.

RESULTS

7 patients reported satisfactory results with their clinical outcome with no feelings of knee instability or objective instability on exam at final follow-up. Post-operative radiographs obtained > 6 months following reconstruction demonstrated well reduced and healed fracture in 5 of 6 patients, with 1 patient demonstrating maintained reduction but incomplete fracture union at 6 months.

CONCLUSION

This novel surgical technique for PLC reconstruction with an avulsed fibular head fracture is a viable alternative to previously described methods. The majority of patients report subjective satisfaction with a stable knee post-operatively.

LEVEL OF EVIDENCE

IV.

Isolated Femoral LCL Avulsion Fracture in the Adult Knee: Two Patient Cases and Literature Review

Avulsion injuries of the LCL most commonly occur at the fibular insertion. Femoral LCL avulsion injuries have only been previously described in pediatric patients or as multiligament knee injury components among adults. This case series with comprehensive literature review describes for the first time 2 cases of isolated LCL femoral avulsion fractures in adults including conservative treatment outcomes. Both patients sustained a strong varus stress mechanism to their right knee, following sport injury or road traffic accident. For both patients, a complete radiographic evaluation including X-rays, MRI, and CT scan confirmed no other associated knee lesions. The femoral LCL avulsion fractures that were observed were minimally displaced and noncomminuted. Furthermore, imagery suggested preserved integrity at the superior lateral genicular artery, adjacent articular capsule, and IT band. Based on clinical and imaging evaluations, the decision was made to follow conservative treatment. By 10 weeks postinjury, both patients were asymptomatic with early radiological fracture healing evidence. Comparative varus stress radiographs at 20° knee flexion revealed no side-to-side differences and clinical exam showed no posterolateral rotatory instability. The second patient case presented with mild femoral LCL attachment calcification on follow-up CT-scan. Following a detailed analysis of anatomic injury characteristics, we suggest that patients with isolated femoral LCL avulsion fractures have low secondary displacement risk provided SLGA, articular capsule, and IT band integrity are present. In contrast to high-grade ligamentous and distal avulsion LCL injuries, we recommend conservative treatment for patients who sustain these lesions.

Treatment of knee sprains in children

The incidence of knee sprains in children is steadily increasing. Skeletal immaturity and anatomical features of the child's ligamentous structures explain the frequency of bone avulsions in young children. Peripheral ligament injuries are the most common and often benign. Nevertheless, associated injuries of the cruciate or patellofemoral ligament(s) are not rare and must not be missed. Age is a determining factor in diagnostic guidance. Anterior intercondylar tibial eminence fractures, otherwise known as tibial spine fractures (TSF), usually occur in young children. Ligamentous distension at the time of the accident would explain the residual laxity that can affect the prognosis of these fractures. The treatment of interstitial ruptures of the ACL follows recommendations that are becoming clearer through multicentric studies. Reparation techniques, historically rejected as ineffective, have again become topical under specific conditions with the aim of preserving the native ACL and its proprioceptive receptors, which are essential in children. ACL reconstruction techniques have made progress in children, especially with techniques adapted from adults. Preservation of growth plates remains pertinent, especially at the femur to avoid growth disorders, thus highlighting the important role paediatric orthopaedic surgeons have in the management of these knee sprains.

Chronic Popliteus Tendon Avulsion Fracture with Chronic Knee Pain and Locking: A Case Report

CASE

A 31-year-old man who had a chronic popliteus avulsion fracture 18 years earlier treated with physical therapy presented with new onset left knee locking after exercising at the gym. Magnetic resonance imaging demonstrated a chronic popliteus avulsion fracture of the lateral femoral condyle. Surgical excision of the nonunited bone fragment was performed.

CONCLUSION

Isolated popliteus avulsion fractures are extremely rare injuries that occur primarily in a skeletally immature patient population and for which treatment options are not well understood. Treatment options include conservative management and early surgical intervention, both of which have inherent risks and benefits. We recommend prompt imaging with computed tomography (CT) to better characterize the degree of injury and follow-up CT imaging in patients who do not undergo early surgical intervention.

Arcuate sign-fibular head avulsion fracture and associated injuries in the pediatric and adolescent population

PURPOSE

To describe the first "arcuate sign" case series in the pediatric population, radiologic features of the associated injuries, management, and how they compare with the adult population.

METHODS

Retrospective study included patients under 18 years of age with a classic "arcuate sign" on radiographs. Data collected included patient demographics, mechanism of injury, and management. Radiographs and advanced imaging (MRI, CT) were reviewed by two musculoskeletal radiologists in a blinded fashion and findings recorded.

RESULTS

Seven patients (4 males, 3 females) with mean age 15 years (range 14-17 years) were included in the study. All 7 injuries were related to sports, 5/7 (71%) being non-contact injuries. Five patients had MRI done-1 LCL injury, MPFL sprain, and MCL sprain were reported; 3 popliteofibular ligament and popliteus sprains were seen; and 3 bone contusions were present on imaging. None of the patients had meniscus or cruciate ligament tears. One patient had an additional fracture of the lateral tibial plateau at the ilio-tibial band attachment and an associated peroneal nerve injury. Five out of seven (71.4%) were treated non-operatively and were able to return back to activity at a mean of 7.2 weeks from injury. Two out of seven (28.6%) needed operative intervention for the fracture but not arthroscopic repair.

CONCLUSION

Pediatric patients with a radiographic arcuate sign tend not to have ACL, PCL, or meniscal injuries, and treatment is predominantly non-operative in contrast to literature reported in adults.

Concomitant Posterolateral Corner Injuries in Skeletally Immature Patients With Acute Anterior Cruciate Ligament Injuries

BACKGROUND

Missed posterolateral corner (PLC) injuries are a known cause of anterior cruciate ligament reconstruction (ACL) failure in the adult population. Failed ACL reconstruction causes significant morbidity in the skeletally immature pediatric population. There is little literature on the character and potential significance of PLC injuries in skeletally immature patients.

METHODS

Magnetic resonance imaging studies of the knee at a tertiary care children's hospital for patients who underwent an ACL reconstruction without PLC surgery were retrospectively reviewed. Demographic variables were obtained through chart review, and magnetic resonance imaging studies were evaluated for PLC (popliteus, fibular collateral ligament, popliteofibular ligament, and arcuate ligament) injury, and ACL, medial collateral ligament (MCL), bone bruise, fracture, and meniscal pathology by an experienced pediatric musculoskeletal radiologist.

RESULTS

A total of 50 patients with a mean age at 13.3 years at injury were analyzed. PLC injuries were found in 26 patients (52%), with 7 patients (14%) having a complete tear of a component of the PLC. There was no association between sex (P=0.35), Segond fracture (P=0.09), meniscus injury (P=0.92), or MCL injury (P=0.24) with the risk of PLC injury. There was an association between patient age and PLC injury (P=0.02). For each additional year of age, the odds of PLC injury increased by 1.8 times (odds ratio, 1.8; 95% confidence interval, 1.4-2.2). There was no association between PLC injury and ACL graft failure (P=0.19).

CONCLUSIONS

Missed PLC injuries are a significant source of morbidity and poor clinical outcomes in the management of concomitant ACL injuries in adults. This study demonstrates the prevalence of PLC injuries in the setting of concomitant ACL injuries in the unique skeletally immature patient population. Incomplete PLC injuries are relatively common. Complete PLC injuries are relatively uncommon. PLC injury was more common in older patients. No other concomitant injury predicted the likelihood of PLC injury. Further research is needed regarding the risk of ACL reconstruction failure from associated PLC injury and the indications for PLC reconstruction in skeletally immature patients.

LEVEL OF EVIDENCE

Level IV-diagnostic study.

An Unusual Complex Posterolateral Osteoligamentous Injury of the Knee in an Adolescent

We present an unusual and complex case of a 16-year-old adolescent male who injured his right knee and sustained combined avulsion injuries of posterior cruciate ligament (PCL) at the tibial insertion site, iliotibial band at lateral tibial condyle, and lateral collateral ligament (LCL) at femoral insertion site akin to osteoligamentous posterolateral corner injury. Anatomical reduction of the femoral LCL avulsion fragment was performed and fixed with a two 4-mm partially threaded cancellous screw. Iliotibial band avulsion was buttressed using Ellis t-plate and fixed with two 4-mm partially threaded cancellous screws. PCL avulsion fracture was conservatively treated owing to minimal displacement. At one-year follow-up, the patient was pain free with a range of motion of 0 to 150 degrees of flexion and had a pain free knee with no instability. Posterolateral corner injury in the patient was very significant as it involved LCL avulsion and iliotibial band avulsion, both of which are part of the posterolateral structures of the knee and also involve the growth plate. Fixation of the avulsion of Gerdy's tubercle with the buttress plate helps to provide additional stability to counteract the deforming forces of the iliotibial band. LCL is also the major stabilizer against varus forces, and hence fixation is required for stability while preventing growth disturbance. PCL avulsion can be treated conservatively in those patients where the fragment is undisplaced or minimally displaced. A good outcome can be achieved in skeletally immature patients who have osteoligamentous posterolateral corner injuries with associated avulsion fractures by using appropriate anatomical reduction and surgical fixation.

Collateral Ligament Knee Injuries in Pediatric and Adolescent Athletes

BACKGROUND

The majority of research on medial (MCL) and lateral (LCL) collateral ligament injuries has focused on adults and combined collateral/cruciate injuries. The purpose of this study was to determine characteristics associated with isolated collateral ligament injuries in adolescents, and assess timing for return to sports.

METHODS

Electronic medical records were queried to identify patients aged below 17 years who sustained a magnetic resonance imaging-confirmed isolated MCL or LCL injury over an 8-year period. Retrospective review then documented patient and injury characteristics and clinical course. General linear modeling was used to analyze risk factors for prolonged return to sports, continued pain or reinjury.

RESULTS

Fifty-one knees (33 in males, 65%), mean age 13.8 years (range, 5 to 17), were identified, of which 40 (78%) had MCL injuries. Over half (29, 57%) of knees had an open distal femoral physis including all 5 bony avulsion injuries. Eleven (22%) had LCL injuries of which 3 (6%) had concurrent posterolateral corner injuries. Forty-two (82%) knees had injuries that occurred during sports. Eleven knees (28%) with MCL tears had a simultaneous patellar instability episode. Knee injuries that occurred during sports had 37% shorter recovery time (P=0.02). Eight knees (16%) experienced a reinjury and 12 (24%) were followed over an extended period of time for various knee issues. Football injuries were more likely to be grade 3 (P=0.03), and football and soccer accounted for all grade III injuries. The mean return to sports was 2.2 months, with grade III cases returning at 2.4 months, and 95% of cases within 4 months.

CONCLUSIONS

Isolated collateral ligament injuries are rare in adolescent athletes. MCL injuries, one-quarter of which occurred in conjunction with patellar instability events, were 4 times more common than LCL injuries, one quarter of which have other posterolateral corner structures involved. Grade III injuries represent 20% to 25% of collateral ligament injuries and occurred most commonly in football and soccer.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Non-operative management of an isolated lateral collateral ligament injury in an adolescent patient and review of the literature

We present a rare case of isolated traumatic pure ligamentous rupture of the lateral collateral ligament of the knee in an adolescent high-level footballer managed non-operatively with a good functional outcome and return to sport in 4 months.

Double-Row Suture Anchor Repair of Posterolateral Corner Avulsion Fractures

Posterolateral corner avulsion fractures are a rare variant of ligamentous knee injury primarily described in the skeletally immature population. Injury is often related to a direct varus moment placed on the knee during sporting activities. Various treatment strategies have been discussed ranging from nonoperative management, to excision of the bony fragment, to primary repair with screws or suture. The described technique is a means for achieving fixation of the bony avulsion using principles familiar to double-row transosseous equivalent rotator cuff repair. Proximal anchors are placed in the epiphysis, and sutures are passed in horizontal mattress fashion. Once tied, the limbs of these same sutures are then passed to more distal anchors. Remaining eyelet sutures can be used to manage peripheral tissue. The final repair provides anatomic reduction and compression of the fragment to its bony bed with minimal extracortical hardware prominence and no violation of the physis. Risks include potential for physeal injury or chondral damage to the lateral femoral condyle through aberrant anchor placement. Postoperative care includes toe-touch weight-bearing restrictions and range of motion restrictions of 0°-90° in a hinged brace for 6 weeks followed by gradual return to activity.

Evaluation of Children with Injuries Around the Knee

Knee injuries are common in children and adolescents. Failure to diagnose and treat these injuries in a timely fashion, can lead to potential complications like malunion, growth disturbances, limb length discrepancy, instability of the joint and in long run, early osteoarthritis or loss of physical activity. Frequently, the pediatrician or the primary care physicians are the first health care providers that the child would present to, and hence it is imperative that the presentation of common knee injuries be recognized. Appropriate referral and management of such injuries in children would minimize the likelihood of untoward consequences and optimize long term outcomes. Most preliminary diagnosis can be established based on adequate history and complete physical evaluation of the knee. This information, supplemented by radiographic assessment and if needed, advanced imaging studies like MRI, would help in definitive diagnosis and in formulating treatment plan for these children. The current review would focus on the important characteristics of common knee injuries in children, the recognition of which would help in the initial evaluation of a child.

Surgical management of isolated popliteus tendon injuries in paediatric patients

Isolated popliteus avulsion injuries are a rare occurrence, especially in the skeletally immature population. Two cases of isolated popliteus tendon avulsion injuries in paediatric patients were identified and successfully managed with suture anchor reattachment of the avulsed fragment in the anatomic position. The objective of this case report is to raise awareness of orthopaedic surgeons to the rarely encountered isolated popliteus tendon injury that can occur in paediatric patients. Level of evidence Expert opinion, Level V.

The origin points of the knee collateral ligaments: an MRI study on paediatric patients during growth

PURPOSE

Different femoral origins for both the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) have been reported in the growing skeleton (epiphyseal and metaphyseal). Knowledge about the exact attachment sites is mandatory for anatomically correct reconstruction. This study assesses the femoral origins of the knee collateral ligaments in skeletally immature individuals using magnetic resonance imaging (MRI).

METHODS

MRIs of 336 knee joints (median age 15 years (range 2-18 years), m = 209 and f = 127) were retrospectively analysed to assess the distances between the femoral origins of the MCL and LCL to the distal femoral growth plate. In 175 patients, the body sizes were additionally retrieved from medical records.

RESULTS

Both MCL and LCL ligament origins were invariably located on the epiphysis. Mean MCL origin-growth plate distance was 9.6 mm (SD 2.1 mm; range 2.2-13.6 mm) in boys and 8.6 mm (SD 1.5 mm; range 3.4-12.0 mm) in girls. Mean LCL origin-growth plate distance was 9.3 mm (SD 1.8 mm; range 4.3-13.0 mm) in boys and 8.2 mm (SD 1.5 mm; range 3.4-11.8 mm) in girls. The distance between the growth plate and both collateral ligaments as well as the length of the LCL correlated positively with patients' age and body size (MCL R(2) = 0.673 and 0.556, LCL R (2) = 0.734 and 0.645, LCL length R(2) = 0.589 and 0.741; all p < 0.001).

CONCLUSIONS

During growth, the femoral origins of the MCL and the LCL are constantly located on the distal femoral epiphysis. There is a linear increase in the distances from the ligaments' origins to the growth plate according to age and body size. This new information may be of clinical importance for reconstructive surgery of the knee's collateral ligaments.

Avulsion fractures of the pediatric knee

Although avulsion fractures of the pediatric knee are uncommon, they are important injuries to recognize because they are frequently associated with adjacent soft-tissue and osteocartilaginous abnormalities. Related injuries, which include entrapment of soft-tissue structures, intra-articular fracture extension, and intra-articular loose bodies, can complicate or alter therapy. The most commonly affected soft-tissue structures include the cruciate ligaments, collateral ligaments and supporting tendons, and extensor mechanism and retinacula. The purpose of this pictorial essay is to review avulsion fractures of the pediatric knee and to highlight associated injuries.

Successful nonoperative treatment of isolated popliteus tendon avulsion fractures in two adolescents

Isolated popliteal tendon avulsion fractures are relatively uncommon in the pediatric population as other posterolateral lateral structures are often involved. This report describes two skeletally immature male patients who presented with knee injuries without ligamentous instability and were subsequently diagnosed with isolated popliteus tendon avulsion fractures. Both of these patients were managed nonoperatively and had subjectively full recoveries. As the treatment for isolated popliteal tendon avulsion fractures is still unclear, the report here may contribute to strategies regarding conservative treatment of these injuries.

Occult Intra-articular Knee Injuries in Children With Hemarthrosis

BACKGROUND

Hemarthrosis after acute knee trauma is a sign of a potentially serious knee injury. Few studies have described the epidemiology and detailed injury spectrum of acute knee injuries in a general pediatric population.

PURPOSE

To document the current injury spectrum of acute knee injuries with hemarthrosis in children aged 9 to 14 years and to describe the distribution of sex, age at injury, type of activity, and activity frequency in this population.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

All patients in the Stockholm County area aged 9 to 14 years who suffered acute knee trauma with hemarthrosis were referred to Astrid Lindgren Children's Hospital, Karolinska University Hospital, from September 2011 to April 2012. The patients underwent clinical examination, radiography, and magnetic resonance imaging (MRI). The type of activity when injured, regular sports activity/frequency, and patient sex and age were registered. The diagnoses were classified into minor and serious injuries.

RESULTS

The study included 117 patients (47 girls and 70 boys; mean age, 13.2 years). Seventy percent had a serious knee injury. Lateral patellar dislocations, anterior cruciate ligament ruptures, and anterior tibial spine fractures were the most common injuries, with an incidence of 0.6, 0.2, and 0.1 per 1000 children, respectively. The sex distribution was equal up to age 13 years; twice as many boys were seen at the age of 14 years. The majority of injuries occurred during sports. Forty-six patients (39%) had radiographs without a bony injury but with a serious injury confirmed on MRI.

CONCLUSION

Seventy percent of the patients aged 9 to 14 years with traumatic knee hemarthrosis had a serious intra-articular injury that needed specific medical attention. Fifty-six percent of these patients had no visible injury on plain radiographs. Physicians who treat this group of patients should consider MRI to establish the diagnosis when there is no or minimal radiographic findings. The most common serious knee injury was a lateral patellar dislocation. This should be taken into consideration to improve prevention strategies and treatment algorithms in pediatric knee injuries.

Ligamentous injuries of the knee: anterior cruciate, medial collateral, posterior cruciate, and posterolateral corner injuries

This article discusses athletic injuries of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and posterolateral corner. Best evidence to date validates that conservative management of ACL ruptures is a reasonable strategy. Current data also seem to advocate nonoperative management of PCL injuries. All isolated MCL injuries, regardless of grade, are usually treated with a brief period of immobilization and symptomatic management. Although the surgical literature often advocates surgical treatment of posterolateral corner injuries, there have been no randomized trials substantiating that these injuries are best treated surgically.