Physeal fractures about the knee

Conventional Radiography Assessment of the Pediatric Knee: Pearls and Pitfalls

Knee pain is one of the most common indications for radiography in the evaluation of musculoskeletal disorders in children and adolescents. According to international guidelines, knee radiographs should be obtained when there is the suspicion of an effusion, limited motion, pain to palpation, inability to bear weight, mechanical symptoms (such as "locking"), and persistent knee pain after therapy. When indicated, radiographs can provide crucial information for the clinical decision-making process. Because of the developmental changes occurring in the knee during growth, the assessment of knee radiographs can be challenging in children and adolescents. Radiologists unfamiliar with the appearance of the knee on radiographs during skeletal maturation risk overcalling or overlooking bone lesions. Image acquisition techniques and parameters should be adapted to children. This article describes the most common challenges in distinguishing pathology from the normal appearance of knee radiographs in the pediatric population, offering some pearls and pitfalls that can be useful in clinical practice.

Minimally Invasive Percutaneous Leverage Reduction in the Treatment of Pediatric Salter-Harris IV and V Distal Femoral Physeal Fractures

OBJECTIVE

Distal femoral physeal fractures (DFPF) are rare but severe injuries in children, and there is no consensus on treatments for Salter-Harris (S-H) IV and V type of DFPF yet. This study aimed to introduce a minimally invasive technique using percutaneous leverage reduction combined with Kirschner wires fixation in treating pediatric DFPF with S-H IV and V type of injury and evaluate the clinical results.

METHODS

From July 2008 to June 2018, the authors' institute (Union Hospital, Tongji Medical College) retrospectively reviewed all patients diagnosed with pediatric DFPF. They were divided into two groups according to received treatment: children in the minimally invasive technique group were treated with a minimally invasive percutaneous leverage reduction technique, and the traditional technique group included the other children who received the conventional open reduction with internal fixation (ORIF). The surgical and clinical results of the two groups were collected and analyzed. The independent sample t-test analysis and the chi-square test were applied to compare continuous and categorical variables.

RESULTS

A total of 14 pediatric patients were recruited, including five females and nine males with DFEF. All eight patients in the minimally invasive technique group and four of the six patients in the ORIF group were treated successfully. One patient in the minimally invasive technique group opted for conservative treatment due to his good functional recovery, while the other two patients in the ORIF group needed further surgery because of the limb length discrepancy. There was a difference in surgery duration (p < 0.001), intraoperative fluoroscopy numbers (p = 0.006), intraoperative blood loss (p < 0.001), radiological union time (p = 0.003) and knee flexion angle (p < 0.001) between two groups. Patients in the minimally invasive technique group all received total knee society (KSS) scores, while the average scores in the ORIF group were lower (100.00 vs. 97.67).

CONCLUSION

The minimally invasive technique is better than conventional ORIF in terms of surgery duration, intraoperative blood loss, radiological union time, knee flexion angle and average KSS score. This percutaneous leverage reduction technique might be a good alternative for treating S-H IV and V DFPF in children.

MRI findings of growth plate fractures of the knee: are there age- and fracture-dependent differences?

OBJECTIVE

To investigate MRI findings in children with physeal fractures of the knee with respect to age, location, and articular involvement.

METHODS

Children with physeal fractures who underwent knee MRI between 2008 and 2021 were included. Two radiologists retrospectively reviewed all examinations to determine articular involvement, findings of physeal instability (perichondral disruption, periosteal entrapment), and internal derangement (cruciate ligament injury, meniscal tear, chondromalacia). Independent samples t, Mann-Whitney U, Pearson's chi-square, and Fisher's exact tests were used to compare findings.

RESULTS

Fifty-six patients (37 boys, 19 girls; mean age: 12.2 ± 2.5 years; 32 distal femur, 24 proximal tibial fractures) included 24(43%) intraarticular fractures. Fractures were more common in the tibia than the femur (67% versus 25%, p = 0.004) and intraarticular fractures were more common in older than younger children (13.1 ± 2.0 versus 11.5 ± 2.7 years, p = 0.01), to associate with chondromalacia (46% versus 12%, p = 0.02) and undergo surgery (33% versus 10%, p = 0.04) when compared to extraarticular fractures. Perichondral disruption (n = 44, 79%) and periosteal entrapment (n = 13, 23%) did not significantly differ based on location or articular involvement (p > 0.05). At a median follow-up of 17.5 months (interquartile range: 1.25-34), 3 patients (2 intraarticular, 1 extraarticular fractures) developed osteoarthritis, osteochondral lesion, and leg-length discrepancy from growth arrest, which required additional surgery.

CONCLUSION

Intraarticular physeal fractures were more common with older children, associate with chondromalacia, and underdo surgical intervention when compared to extraarticular fractures of the knee. While MRI findings of physeal instability were common, no significant differences were found between fractures based on anatomic location or fracture pattern.

Complex distal femoral fracture treated with interfragmentary screws and medial buttress plating

A woman in her 70s suffered a motor vehicle accident, resulting in an intraarticular, distal femoral fracture with a unique fracture pattern. A 3D-printed model was obtained using the preoperative CT scan for surgical planning. Anatomic reduction was achieved using a medial parapatellar approach and the fracture was fixed with a medial buttress plate and interfragmentary screws. After 18 months, the patient presented a fair Knee Society Score of 62.

Anterior Cruciate Ligament Rupture in Skeletally Immature Patients

In the past 20 years, sports injuries in pediatric and adolescent athletes have increased dramatically, with anterior cruciate ligament (ACL) injuries accounting for more than 25% of all knee injuries at this age. Diagnosis is based on detailed clinical history, physical examination, and imaging assessment, where magnetic resonance imaging plays a central role. The growing immature skeleton presents specific characteristics, which require unique methods for surgical reconstruction, ideally avoiding the physes or minimizing the risk of damaging them. Specific rehabilitation protocols are needed, and these patients face a higher risk of recurrent and contralateral ACL injury. Nonsurgical treatment or delayed reconstruction has been associated with persistent instability, activity modifications, worst functional outcomes, and increased risk of irreparable injuries to menisci and articular cartilage. Consequently, surgical stabilization is the preferred treatment for most patients, despite the eventual risk of angular deformities or limb-length discrepancies due to iatrogenic physeal injury. A variety of surgical techniques have been described, depending on the skeletal maturity and growth remaining. Targeted prevention programs play a key role in reducing the risk of ACL injury, are easy to implement, and require no additional equipment. High-quality evidence supports its use in all pediatric athletes.

Ogden Type I to III tibial tubercle fractures in skeletally immature patients: is routine anterior compartment fasciotomy of the leg indicated?

PURPOSE

Determine the frequency of compartment syndrome of the leg after displaced, operatively treated modified Ogden I to III tibial tubercle fractures (TTFxs), evaluate the preoperative assessment and use of advanced imaging, and need for prophylactic fasciotomies.

METHODS

Retrospective analysis of operatively treated, displaced modified Ogden I to III TTFxs, at our level 1 paediatric trauma centre between 2007 and 2019. Modified Ogden Type IV and V fracture patterns were excluded. Fracture patterns were determined by plain radiographs.

RESULTS

There were 49 modified Ogden I to III TTFxs in 48 patients. None had signs nor symptoms of vascular compromise, compartment syndromes or impending compartment syndromes preoperatively. In all, 13 of the 49 fractures underwent anterior compartment fasciotomy at surgery; eight of the 13 had traumatic fascial disruptions, which were extended surgically. All incisions were primarily closed. There were no instances of postoperative compartment syndromes, growth arrest, leg-length discrepancy or recurvatum deformity postoperatively. All patients achieved radiographic union and achieved full range of movement.

CONCLUSION

The potentially devastating complications of compartment syndrome or vascular compromise following TTFx did not occur in this consecutive series of patients over 12 years. The presence of an intact posterior proximal tibial physis and posterior metaphyseal cortex (Modified Ogden TTFx Type I to III) may mitigate the occurrence of vascular injury and compartment syndrome. Plain radiographs appear appropriate as the primary method of imaging TTFxs, with use of advanced imaging as the clinical scenario dictates. Routine, prophylactic fasciotomies do not appear necessary in Ogden I to III TTFxs, but should be performed for signs and symptoms of compartment syndrome.

LEVEL OF EVIDENCE

Level IV.

Enlightenment of Growth Plate Regeneration Based on Cartilage Repair Theory: A Review

The growth plate (GP) is a cartilaginous region situated between the epiphysis and metaphysis at the end of the immature long bone, which is susceptible to mechanical damage because of its vulnerable structure. Due to the limited regeneration ability of the GP, current clinical treatment strategies (e.g., bone bridge resection and fat engraftment) always result in bone bridge formation, which will cause length discrepancy and angular deformity, thus making satisfactory outcomes difficult to achieve. The introduction of cartilage repair theory and cartilage tissue engineering technology may encourage novel therapeutic approaches for GP repair using tissue engineered GPs, including biocompatible scaffolds incorporated with appropriate seed cells and growth factors. In this review, we summarize the physiological structure of GPs, the pathological process, and repair phases of GP injuries, placing greater emphasis on advanced tissue engineering strategies for GP repair. Furthermore, we also propose that three-dimensional printing technology will play a significant role in this field in the future given its advantage of bionic replication of complex structures. We predict that tissue engineering strategies will offer a significant alternative to the management of GP injuries.

The Medial Femoral Condyle Flap in the Pediatric Patient

BACKGROUND

The use of free flaps from the medial femoral condyle has grown in popularity and is now a workhorse in the reconstruction of skeletal defects. The utility of this technique has not yet been described for the pediatric patient population. The authors present their series of pediatric patients who underwent surgery using a medial femoral condyle free flap or a variant thereof in skeletal reconstruction and demonstrate the efficacy of this technique in this population.

METHODS

A multi-institutional retrospective review of patients aged 18 years or younger who required a medial femoral condyle flap for skeletal reconstruction was undertaken. Operative technique, radiographs, and clinical outcomes were recorded. A novel technique (Innocenti) was used to avoid the distal femoral physis in which a Kirschner wire was placed under fluoroscopic guidance just proximal to the growth plate.

RESULTS

Thirteen patients met inclusion criteria, with an average age of 14.7 years (range, 7 to 18 years) and mean follow-up of 28 months (range, 3 to 120 months). Six were skeletally immature at the time of medial femoral condyle harvest, with the last patient having organic bone disease, putting her at risk for pathologic fracture. All 13 patients achieved bony union, and no patients suffered pathologic fractures or physeal injuries; no patients developed length discrepancies.

CONCLUSIONS

The authors present the first series of corticocancellous medial femoral condyle free flaps in the pediatric population along with a novel technique to avoid injury to the physis in skeletally immature patients. This technique is effective for a variety of skeletal defects or nonunions and is safe for growing patients without causing physeal arrest or growth disturbance.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Epidemiology of pediatric femur fractures in children: the Swedish Fracture Register

Background

Although femur fractures in children are rare, they are the most common fractures in need of hospitalization. We sought to describe the epidemiology and treatment of pediatric femur fractures recorded in the Swedish Fracture Register (SFR). We also studied the relationship between femur fractures, age, sex, fracture pattern, injury mechanism, seasonal variation and treatment.

Methods

This nationwide observational register study was based on the pediatric part of the SFR. We included all patients < 16 years of age who were registered in the SFR from 2015 to 2018.

Results

Of the 709 femur fractures, 454 (64%) occurred in boys. Sixty-two of these fractures were proximal (9%), 453 shaft (64%) and 194 distal (27%). A bimodal age distribution peak was observed in boys aged 2–3 and 16–19 years. In contrast, the age distribution among girls was evenly distributed. Younger children were mainly injured by a fall, whereas older children sustained their fracture because of traffic accidents. Non-surgical treatment prevailed among younger children; however, prevalence of surgical treatment increased with age.

Conclusions

We found a lower ratio between boys and girls (1.8:1) compared to earlier studies. The bimodal age distribution was seen only in boys. Falls were the most common injury in younger children, whereas traffic-related accidents were the most common in adolescents. With age, there was a corresponding increase in surgical treatment.

Tibial Apophyseal Percutaneous Pinning in Skeletally Immature Dogs: 25 Cases (2016-2019)

OBJECTIVE

 The aim of this study was to report the clinical experience with fluoroscopically guided tibial apophyseal percutaneous pinning (TAPP) for tibial tuberosity avulsion fractures (TTAF).

STUDY DESIGN

 This is a retrospective case series.

MATERIALS AND METHODS

 Medical records of skeletally immature dogs (n = 25) were reviewed. The association of pin design [smooth (SP); negatively threaded (NTP)], pin insertion angles, TTAF-type, age and breed with various outcome variables was statistically evaluated. Long-term follow-up was assessed via direct examination, radiographs, questionnaires and videos.

RESULTS

 Mean age, weight and surgery times were 6.2 months, 9.6 kg and 21 minutes respectively. No major complications occurred among the 19 SP and 6 NTP; no pin broke. Seromas and patellar desmitis rates were higher with SP (11/19; 16/19) versus NTP (0/6; 2/6) (p = 0.02; 0.03). The median horizontal pin cross angles for cases without and with desmitis were 40 and 26 degrees respectively (p = 0.047). Explantation was needed in 5/19 SP and 0/6 NTP cases. The mean tibial plateau angle (TPA) changed significantly between initial (25.6 degrees) and follow-up (18.8 degrees) radiographs (p = 0.0002). Long-term outcome, obtained at a mean of 19.9 months, was excellent in all cases.

CONCLUSION

 Tibial apophyseal percutaneous pinning can be considered to treat TTAF. Divergent pin placement and using NTP might reduce complications. Tibial plateau angle should be monitored until skeletal maturity has been reached. Long-term outcome post TAPP can be expected to be excellent.

Substantial decrease in paediatric lower extremity fracture rates in German hospitals in 2017 compared with 2002: an epidemiological study

Background

There are no recent studies on the frequency of paediatric lower extremity fractures in Germany. The aims of this study were to report fracture rates of paediatric lower extremity fractures treated in German hospitals in 2002 and 2017 and to detect changes over time as well as to evaluate the gender and age distribution for each fracture location.

Methods

Data from the German National Hospital Discharge Registry, which covers over 99% of all German hospitals, were used for this study. The absolute frequencies and incidence of lower extremity fractures as well as age at the time of fracture and gender were included in the data. The population was subdivided into four age groups: 0–4, 5–9, 10–14, and 15–19 years. The boy: girl ratio (BGR) for all fracture locations was calculated by dividing the absolute frequency of boys by that of girls. The fracture incidence in 2017 was compared with 2002 by calculating the incidence rate ratio (IRR).

Results

The total number of fractures decreased by 39.9% from 2002 to 2017. The most common fracture locations in 2002 were femoral shaft, tibial shaft, distal tibia, and lateral and medial malleolus; the absolute number of all these fractures was lower in 2017 than in 2002 in all age groups. The incidence of hip and thigh fractures, knee and lower leg fractures, and foot fractures decreased by 39.0, 41.1, and 33.3%. Proximal tibial fractures increased both in absolute numbers and in incidence in the age groups 0–4, 10–14, and 15–19 years (IRR ≥ 1.1). The overall BGR was 2.3 in 2002 and 2.0 in 2017, indicating that the number of girls relative to that of boys who suffered a lower extremity fracture was higher in 2017 than in 2002. Furthermore, the BGR of all fracture locations increased with age in both years.

Conclusions

The number of paediatric lower extremity fractures treated in German hospitals in 2017 was significantly lower than that in 2002. However, the fracture frequency in girls decreased to a lesser extent than that in boys. The incidence of proximal tibial fractures increased.

Fracture of the anterior tibial tuberosity in children

Fractures of the anterior tibial tuberosity during childhood are an infrequent pathology (around 3% of all proximal tibial fractures), but the incidence of this injury has risen over recent years, likely due to the increased involvement of this age group in sports activities.

This fracture is more commonly seen in children 12–14 years old.

It is vital to identify the anatomical structures associated with this type of fracture, along with the pathophysiological mechanisms involved.

Treatment includes non-operative and operative options, with the goal of achieving articular congruency, restoring the extensor mechanism function, and avoiding damage to the proximal tibial physis.

Understanding the management of this fracture, and the complications that might arise, is critical. The provision of an appropriate clinical management plan and the avoidance of complications are vital in the prevention of disability.

Cite this article: EFORT Open Rev 2020;5:260-267. DOI: 10.1302/2058-5241.5.190026

Anatomic Dissection and CT Imaging of the Anterior Cruciate and Medial Collateral Ligament Footprint Anatomy in Skeletally Immature Cadaver Knees

BACKGROUND

Anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries in skeletally immature patients are increasingly recognized and surgically treated. However, the relationship between the footprint anatomy and the physes are not clearly defined. The purpose of this study was to identify the origin and insertion of the ACL and MCL, and define the footprint anatomy in relation to the physes in skeletally immature knees.

METHODS

Twenty-nine skeletally immature knees from 16 human cadaver specimens were dissected and divided into 2 groups: group A (aged 2 to 5 y), and group B (aged 7 to 11 y). Metallic markers were placed to mark the femoral and tibial attachments of the ACL and MCL. Computed tomography scans were obtained for each specimen used to measure the distance from the center of the ligament footprints to the respective distal femoral and proximal tibial physes.

RESULTS

The median distance from the ACL femoral epiphyseal origin to the distal femoral physis was 0.30 cm (interquartile range, 0.20 to 0.50 cm) and 0.70 cm (interquartile range, 0.45 to 0.90 cm) for groups A and B, respectively. The median distance from the ACL epiphyseal tibial insertion to the proximal tibial physis for groups A and B were 1.50 cm (interquartile range, 1.40 to 1.60 cm) and 1.80 cm (interquartile range, 1.60 to 1.85 cm), respectively. The median distance from the MCL femoral origin on the epiphysis to the distal femoral physis was 1.20 cm (interquartile range, 1.00 to 1.20 cm) and 0.85 cm (interquartile range, 0.63 to 1.00 cm) for groups A and B, respectively. The median distance from the MCL insertion on the tibial metaphysis to the tibial physis was 3.05 cm (interquartile range, 2.63 to 3.30 cm) and 4.80 cm (interquartile range, 3.90 to 5.10 cm) for groups A and B, respectively.

CONCLUSION

Surgical reconstruction is a common treatment for ACL injury. Computed tomography scanning of pediatric tissue clearly defines the location of the ACL and MCL with respect to the femoral and tibial physes, and may guide surgeons for physeal respecting procedures.

CLINICAL RELEVANCE

In addition to ACL reconstruction, recent basic science and clinical research suggest that ACL repair may be more commonly performed in the future. MCL repair and reconstruction is also occasionally required in skeletally immature patients. This information may be useful to help surgeons avoid or minimize physeal injury during ACL/MCL reconstructions and/or repair in skeletally immature patients.

Tibial tubercle avulsion fractures in children

PURPOSE OF REVIEW

To summarize and discuss the fundamentals of pediatric tibial tubercle avulsion fractures (TTAFs) including preferred imaging modalities, systems for fracture classification, frequently associated injuries, treatment options, outcomes, and common complications.

RECENT FINDINGS

Although TTAFs amount to fewer than 1% of all physeal injuries in children, the incidence is increasing, likely because of greater participation in high-level athletics.

SUMMARY

TTAFs tend to occur in adolescents nearing skeletal maturity who engage in sports with repetitive jumping. The most popular classification system was proposed by Ogden, which defines five fracture types based on the fracture pattern and extent of fragment displacement. Treatment can be nonsurgical or surgical, and indications depend on fracture type. Most fractures are surgical candidates and can be repaired with open reduction and internal fixation (ORIF) or arthroscopy. Arthroscopic approaches can reveal associated soft tissue injuries, such as meniscal tears, and confirm articular reduction. The most common postoperative complication is irritation because of hardware. With proper treatment, both nonsurgical and surgical outcomes are excellent. TTAFs have high rates of union and patients typically return to sports.

Outcomes of surgical treatment of the tibial tuberosity fractures in skeletally immature patients: an update

Tibial tubercle fractures in adolescents are uncommon injuries which typically occur in 12-16 year-old males involved in athletic activities. We hereby present our experience in the surgical treatment of such lesion. By reviewing all the tibial tuberosity fractures treated surgically at our institution between January 2012 and January 2016, we were able to identify 12 patients (14 fractures), of which 11 males and 1 female, whose average age at the time of the trauma was of 14.05. According to the Ogden classification, we identified two Type IIA fractures, one Type IIB fracture, one Type IIIB fracture, four Type IIIC fractures, four Type IVA fractures, one Type IVB fracture and one Type IVC fracture. All patients underwent surgical treatment-9 fractures ORIF (64.3%), 5 CRIF (35.7%)-and postsurgical immobilization in plaster cast for 15 days, with a non-weight bearing period of approximately 4.7 weeks. They all had a complete ROM recovery and returned to preinjury activities within 4.1 months on average. The successful union of the fracture was observed in all patients, and no cases of meniscal lesions, compartment syndrome, infections, lower limb length discrepancy or axial deviations emerged at the minimum follow-up of 24 months. After an average period of 11 months and 2 weeks (range 6.1-16.3), all patients underwent surgical implant removal. Our experience matches the outcomes described in the literature, therefore confirming the safety and effectiveness of this treatment.

Bilateral Tibial Tubercle Avulsion Fractures in Children - Clinical Results of a Rare Fracture

BACKGROUND

Tibial tubercle avulsion fractures are rare, they represent less than 1% of all physeal fractures. Compared to monolateral tibial tubercle avulsion fractures, bilateral occurrence is even rarer. The purpose of this study is to report about the so far largest group of bilateral avulsion fractures and to compare them to unilateral fractures as well as to current literature.

METHOD

All patients who suffered from bilateral tibial tubercle fractures between January 2009 and March 2019 were included. All medical records and radiographs were reviewed and a clinical follow-up was performed. The examined criteria were age, gender, mechanism of injury, classification, risk factors, complications, management and outcomes. Clinical outcome was measured using the well established Tegner activity scale and Lysholm-Gillquist score. The same criteria were analyzed in a literature review of bilateral tibial tubercle fractures to compare our results to available literature.

RESULTS

We found four children with bilateral tibial tubercle avulsion fractures. All patients were male with a mean age of 14.5 ± 0.7 years (13 - 15). Mean follow-up examination was 13.6 ± 6.5 months (8 - 29) after surgery. The avulsions occurred during jumping activities in all cases. All children could no longer stand or move because of sudden pain in the knee. We found type IV fractures in three cases, type III fractures in four cases and one type V fracture according to the Ogden classification. All children were treated by open or closed reduction and stabilization with screws or K-wires. Follow-up showed complete fracture healing without complications in all patients. There were no changes in Tegner activity scale and Lysholm-Gillquist Score and knee function comparable to prior to the accident was achieved in all cases.

CONCLUSION

Good clinical results without restrictions regarding function of the knee joint can be achieved by direct operative treatment of bilateral tibial avulsion fractures. A reduction in sporting activity has not to be expected. There were no differences between bilateral or unilateral tibial tubercle avulsion fractures.

Knee Extension Does Not Reliably Reduce Acute Type II Tibial Spine Fractures: MRI Evaluation of Displacement During Extension Versus Resting Flexion

Background:

Type II tibial spine avulsion (TSA) fractures have traditionally been managed by first attempting to achieve closed reduction with extension and immobilization, with surgical indications reserved for those who fail to reduce within 3 mm. However, the frequency with which appropriate reduction can be achieved is largely unknown.

Purpose:

To evaluate changes in displacement of type II TSA fractures by comparing magnetic resonance imaging (MRI) scans obtained with the knee in flexion and in extension.

Study Design:

Case series; Level of evidence, 4.

Methods:

Ten patients with type II TSA fractures were identified. Fracture displacement was measured using 3 images for each patient: (1) initial lateral view radiography, (2) sagittal-plane MRI of the knee in resting flexion, and (3) sagittal-plane MRI of the knee in passive extension. Maximum displacement of the bony fragment was measured in the 2 MRI studies for all patients, and the corresponding change in displacement was calculated. Displacement in flexion was compared with displacement in extension using a paired-sample t test. Statistical significance was set at P < .05.

Results:

The displacement distance of the bony fragment was reduced by a mean of 0.97 mm on MRI when the knee was in extension compared with flexion in patients with type II TSA fractures (P = .02). Mean displacement with extension was 6.14 mm, with no fractures reduced below 4 mm. The largest reduction observed was 2.80 mm. The displacement distance increased in 2 knees with extension. The intermeniscal ligament (IML) was entrapped in 4 of 10 patients; however, the amount of reduction achieved did not differ based on the presence of IML entrapment (P = .85).

Conclusion:

While the amount of tibial spine displacement warranting surgical treatment can be debated, the study findings suggest that knee extension is not reliable in obtaining adequate closed reduction for type II TSA fractures. Management decisions may need to be based on the initial displacement distance of the fracture, with a lower threshold for operative treatment than previously recognized.

[Bony knee injuries in childhood and adolescence]

While fractures around the knee are known to be rare, physicians have encountered a rise in the frequency due to the increased participation of children and adolescents in high-impact sports at a younger age. Even if the treatment of fractures in some cases resembles that in adults, the diagnostics and treatment in childhood and adolescence require a hígh level of experience in order avoid possible sequelae and to enable early recognition. Thorough diagnostics using clinical and imaging investigations as well as a precise weighing up of the treatment are essential to minimize differences in leg length and axial malpositioning of the leg. A decision between conservative and operative treatment is made for both the femur and tibia depending on the type of fracture. Decisive is the degree of dislocation of the fracture. In operative treatment, the axis conform reduction and subsequent stress stable treatment are particularly decisive. Avulsion trauma, bony avulsions of the intercondylar eminence and patellar injuries are also treated conservatively with immobilization or surgically with the aid of various fixation techniques, depending on the degree of dislocation.

No Growth Disturbance After Trochleoplasty for Recurrent Patellar Dislocation in Adolescents With Open Growth Plates

BACKGROUND

Trochlear dysplasia is the most important risk factor for patellofemoral instability among adolescents; therefore, trochleoplasty to reshape the trochlear groove is the treatment of choice for patients with high-grade trochlear dysplasia. However, in the presence of open growth plates, there is a potential risk of injury to the distal femoral growth plate and subsequent growth disturbance. As such, most authors do not recommend trochleoplasty for skeletally immature patients. The effect of trochleoplasty on femoral growth when performed before closure of the distal femoral physis remains unclear.

HYPOTHESIS

For patients with open growth plates and an expected growth <2 years, trochleoplasty does not cause growth disturbance of the distal femur.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Eighteen consecutive adolescents (18 knees) with open physes and severe trochlear dysplasia underwent thin flap trochleoplasty. Pre- and postoperative radiographic examination included anteroposterior and lateral views to assess leg axis and patella alta. A preoperative radiograph of the left hand was performed to measure skeletal age. Magnetic resonance imaging was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove distance. Evaluation included pre- and postoperative physical examination with evaluation of leg length and leg axis, Kujala score, and Tegner activity score.

RESULTS

The median age at the time of operation was 12.6 years (range, 12.2-13.3 years) for girls and 14.5 years (14.0-15.4 years) for boys. The mean follow-up after operation was 2.3 years after surgery (range, 2.0-3.0 years). At follow-up for all patients, the growth plates of the knee were closed. Impairment of growth of the distal femur was found neither clinically nor radiographically. No recurrent dislocation occurred. The median Kujala score improved significantly from 67 (range, 54-75) preoperatively to 89.5 (range, 78-96) at follow-up ( P < .01). The median visual analog scale showed significant pre- to postoperative improvement from 5 (range, 3-7) to 1 (range, 0-3) ( P < .01). The activity level according to the Tegner activity score did not change significantly.

CONCLUSION

In this study, trochleoplasty as a treatment for patellofemoral instability of patients with open physes and an expected growth of not more than 2 years showed good clinical results without redislocation and with no growth disturbance. Therefore, for selected adolescent patients with high-grade trochlear dysplasia, trochleoplasty can be safely performed up to 2 years before the projected end of growth.

Combined avulsion fracture of the tibial tubercle and patellar tendon rupture in pediatric population: case series and review of literature

Simultaneous occurrence of tibial tubercle fracture and patellar tendon avulsion with double-hit injury of the knee extensor mechanism is an extremely rare condition. However, they become more frequent due to increased participation in sports and high-energy recreational activities at younger age. It represents a frequently missed diagnosis; therefore, high index of suspicion is required for the diagnosis of such injuries to avoid delays in the treatment which would lead to possible suboptimal functional outcome. Only few case reports of such injuries were reported in the literature with limited information regarding frequency, diagnosis, and outcome in children. To the best of our knowledge, this is the first case series with such type of injury.