Purpose Tibiofemoral rotation through the knee joint, speciically relative external tibial rotation, has been identiied as a potential contributing factor to patellar instability. The purpose of this study is to investigate the relationship between severity of instability with degree of tibiofemoral rotation in three clinical cohorts: ixed or obligatory dislocators (in which the patella either is constantly laterally dislocated or laterally dislocates with every instance of knee lexion, respectively), standard traumatic instability patients, and normal controls. Methods A retrospective study was performed with three cohorts from April 2009 to February 2019: ixed or obligatory dislocators, standard traumatic instability patients, and controls with normal magnetic resonance imaging (MRI) of the knee. All ixed or obligatory dislocation patients from the study time frame were analyzed; controls and standard traumatic instability patients were randomly selected. Inclusion criteria were age under 18 years and qualifying diagnosis; exclusion criteria were outside institution MRI and previous MPFL reconstruction or tibial tubercle osteotomy. Tibiofemoral rotation was measured blindly on initial axial MRI using the posterior femoral and tibial condylar lines. Tibial tubercle to trochlear groove distance (TT-TG) was measured. Intraclass correlation coeicient (ICC) was calculated among four measurers. Results A total of 100 patients were included, 20 ixed or obligatory dislocators, 40 standard traumatic instability patients, and 40 controls. Median age was 13.2 years (range 10-17 years), with 55 females. Age was signiicantly higher in the standard traumatic instability group than both the control (p < 0.001) and ixed or obligatory dislocator groups (p = 0.003). ICC for TT-TG and tibiofemoral rotation were 0.92 and 0.96, respectively. Fixed or obligatory dislocator patients averaged 8.5° external tibiofemoral rotation, standard traumatic instability patients 1.6° external tibiofemoral rotation, and controls 3.8° internal tibiofemoral rotation. Both tibiofemoral rotation and TT-TG were highest in the ixed or obligatory dislocator cohort, followed by the standard traumatic instability cohort, and lowest in the controls (p < 0.0001 for tibiofemoral rotation and TT-TG). Multivariate analysis showed no correlation between age and tibiofemoral rotation. Conclusions Measurement of tibiofemoral rotation was reproducible with excellent interrater reliability. The degree of tibiofemoral rotation is correlated with severity of patellar instability, with the greatest external tibiofemoral rotation in ixed or obligatory dislocator patients, followed by standard traumatic instability patients, and slight internal tibiofemoral rotation in controls. High external tibiofemoral rotation may be an important pathoanatomic factor in ixed or obligatory dislocators, and with further understanding may become a prognostic factor or surgical target. Level of evidence III.

Background: Osgood-Schlatter disease (OSD) is a traction apophysitis of the tibial tubercle caused by repetitive strain and chronic avulsion from the patellar tendon. No widely accepted anatomic risk factors have been associated with OSD. Purpose: To determine if OSD is associated with increased posterior tibial slope (PTS). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Forty knees with OSD and 32 control knees examined by the senior author between 2008 and 2019 were included. Patients 10 to 15 years of age with a clinical diagnosis of OSD and available lateral radiograph and magnetic resonance imaging (MRI) were eligible. Age- and sex-matched patients with a history of knee pain but no evidence of OSD on clinical examination and without significant pathology on lateral radiograph and MRI were included in the control group. PTS was defined as the angle between a reference line perpendicular to the proximal anatomic axis and a line drawn tangent to the uppermost anterior and posterior edges of the medial tibial plateau. Measurements were carried out in duplicate on true lateral radiographs by 2 blinded investigators. Interrater reliability of PTS measurements was evaluated using intraclass correlation coefficient (ICC). The independent samples t test was used to compare PTS between the OSD and control knees. Results: The mean age was 12.6 ± 1.6 years and 51% (37/72) of the knees were from male youth. There were no differences in age, sex, and laterality of knees between the OSD and control groups. The mean PTS was significantly higher in the OSD group (12.23°± 3.58°) compared with the control group (8.82°± 2.76°; P < .001). The ICC was 0.931 (95% CI, 0.890-0.957), indicating almost perfect interrater reliability. Conclusion: This study identifies an association between OSD and increased PTS. The clinical implications of this finding have not yet been elucidated. It may be speculated that in patients with OSD, stress from the extensor mechanism through the patellar tendon loads the anterior portion of the tibia disproportionately to the posterior segment, thereby resulting in asymmetric growth and an increased PTS.

Recent literature has identified a population of active adolescents aged 13 to 15 years who are at high risk for anterior cruciate ligament graft rupture. Addressing the anterolateral complex during primary anterior cruciate ligament reconstruction has recently re-emerged in the literature, with various techniques available. This paper aims to describe a lateral extra-articular tenodesis procedure using the iliotibial band with a modified Lemaire technique. This procedure is recommended for active adolescents at a high risk of graft re-tear as an enhancement to primary anterior cruciate ligament reconstruction with soft-tissue graft.

Patellofemoral instability is a common orthopedic condition in children and adolescents, with recurrent instability often requiring surgical intervention. Age, bilateral instability, and various anatomic features such as trochlear dysplasia, patella alta, increased tibial tubercle to trochlear groove distance, and patellar tilt have all been described as risk factors for recurrent patellar instability. Medial patellofemoral ligament reconstruction has become the mainstay of treatment for addressing recurrent patellar instability in skeletally immature patients. For some patients, additional interventions such as distal realignment and guided growth procedures may be required to address anatomic pathology. This article discusses various risk factors associated with patellofemoral instability, reconstruction techniques, and a case example.

Historically, one of the most common graft choices for anterior cruciate ligament (ACL) reconstruction in the pediatric population has been the hamstring autograft. Although pediatric ACL reconstructions with a hamstring autograft have allowed a majority of children and adolescents to return to athletics, it has been reported that anywhere between 6% and 38% of these patients will go on to experience subsequent graft rupture. The quadriceps tendon autograft is an alternative to the hamstring tendon autograft that demonstrates superior preliminary outcomes, and we currently recommend it for skeletally immature patients undergoing primary and revision ACL reconstruction. This paper aims to describe our technique for an open full-thickness quadriceps tendon harvest with repair.

Background: Pre- and postoperative standing hip-to-ankle radiographs are critical for monitoring potential postoperative growth arrest and resultant deformities after pediatric anterior cruciate ligament (ACL) reconstruction. Purpose: To determine the prevalence of apparent preoperative leg-length discrepancies (LLDs) that resolve at the first postoperative radiographic examination in patients undergoing ACL reconstruction in order to understand what proportion of the noted preoperative deformities may have been inaccurate. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review of prospectively collected preoperative and first postoperative full-length hip-to-ankle radiographs was performed in a cohort of skeletally immature patients who had an acute ACL injury and underwent subsequent surgical reconstruction. Leg length measurements for both the injured and the uninjured legs were obtained for comparison. Results: A total of 112 patients (mean age, 12.7 ± 1.7 years) were included (79 boys and 33 girls). Leg-length measurement interrater reliability among 3 raters for 25 randomly chosen images was nearly perfect (intraclass correlation coefficient, 0.996; 95% CI, 0.994-0.998). At baseline, there was no apparent preoperative LLD (<5 mm) in 48% (n = 54) of participants, while 37% (n = 41) displayed a small apparent LLD (5 to <10 mm), 12% (n = 13) displayed a moderate apparent LLD (10 to <15 mm), and 4% (n = 4) displayed a large apparent LLD (≥15 mm). Of the patients with an apparent preoperative LLD, 66% (n = 38) of them tore their ACL on the leg measuring shorter. At first postoperative radiographs, 48% (n = 28) of patients with an apparent preoperative LLD showed resolution to no LLD: 46% (n = 19) of patients with a small apparent preoperative LLD, 54% (n = 7) of patients with a moderate apparent LLD, and 50% (n = 2) of patients with a large apparent LLD. Conclusion: A high percentage of patients (48%) with apparent preoperative LLDs showed resolution to no LLDs by their first postoperative imaging, indicating that preoperative hip-to-ankle radiographs display some false LLDs in patients with recent ACL tears who are unable to fully extend their injured leg and bear weight.

Patellofemoral instability is a common problem affecting children and adolescents, with recurrent instability often requiring surgical intervention. Medial patellofemoral ligament (MPFL) reconstruction has become a mainstay for the treatment of patellofemoral instability because of the biomechanical importance of the MPFL against lateral dislocation as well as the high frequency of MPFL injury following traumatic patellar dislocation. The concern in managing skeletally immature patients is the potential for injury to the distal femoral physis. Here, we highlight 2 techniques for MPFL reconstruction. The first technique utilizes a hamstring autograft. The steps include: Step 1: Harvest the semitendinosus graft from a 2-cm posteromedial incision with use of an open tendon harvester proximally and a closed tendon harvester distally. Step 2: Prepare the graft for double-bundle reconstruction, allowing for approximately 50 to 60 mm for the reconstructed MPFL and 15 to 20 mm for graft placement within the patella and femoral sockets. Step 3: Use a guidewire and reamer to create 2 patellar sockets approximately 15 mm long each. Step 4: Use a guidewire under fluoroscopy to position and create a femoral socket distal to the distal femoral physis approximately 15 mm long. Step 5: Fix the graft on the femur with use of a tenodesis screw, pass the graft through the soft-tissue space between the fascia and synovium to the superior half of the patella, then dock the free ends of the graft onto the 2 patellar sockets with “PEEK (polyetheretherketone) SwiveLocks (Arthrex)” while the knee is in 30° of flexion. We also review a second technique of docking the hamstring graft onto the adductor tubercle and suturing it proximally to the deep distal medial aspect of the quadriceps tendon. Although only a limited number of studies have reported the outcomes of MPFL reconstruction in skeletally immature patients, such studies have demonstrated a high return to preoperative level of sports activity and a reduced prevalence of recurrent patellar instability.

Purpose To highlight important diagnostic and treatment considerations in patients who present with bifocal patellar tendon avulsion fractures from the tibial tubercle and inferior patellar pole. Methods Radiographic presentation, surgical technique, and complications of 5 children who sustained bifocal patellar tendon avulsion fractures with ≥6 months postoperative follow-up were retrospectively reviewed. Hospital for Special Surgery (HSS) Brief Functional Activity Scale (HSS Pedi-FABS), Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference, PROMIS mobility, and Pediatric International Knee Documentation Committee Scale (Pedi-IKDC) were assessed at most recent follow-up. Results Five children (4 boys, 1 girl) presented with bifocal patellar tendon avulsion fractures with a median follow-up of 12.8 months (range 7.7 to 26.4). In 1 case, advanced imaging was not pursued, and the bifocal nature of injury was subsequently discovered intraoperatively. In all other cases, magnetic resonance imaging (MRI) correctly characterized the bifocal injuries and revealed the full extent of fractures and soft tissue injury. Surgical management involved suture anchor repair with heavy nonabsorbable sutures. Postoperative functional and patient-reported outcomes were within the range of population healthy/normative values (for those that were available for comparison, e.g., Pedi-IKDC), and clinically relevant improvement was noted when comparing preoperative and postoperative patient-reported outcome measures of both pain and mobility. Conclusions Advanced imaging (e.g., MRI) is required to understand the full extent of injury and should be obtained in the setting of traumatic patella alta to evaluate for the presence of a bifocal lesion and plan surgical intervention accordingly. These patients demonstrate satisfactory functional and patient-reported outcomes after operative repair. Level of Evidence IV, therapeutic case series.