Effect of Varus-Producing Distal Femoral Osteotomy and High Tibial Osteotomy on Compartment Pressures and Contact Area at Varying Degrees of Knee Flexion.

Background: In patients with valgus alignment and degenerative changes in the lateral compartment, both distal femoral osteotomy (DFO) and high tibial osteotomy (HTO) can be used to unload the lateral compartment. Prior studies have shown that in valgus knees, the tibial wear is posterior and DFO exerts the greatest effect in extension; however, its effect is decreased as flexion angle rises. Hypothesis: Medial closing-wedge (MCW) HTO would significantly decrease contact area, mean contact pressure (MCP), and peak contact pressure (PCP) in the lateral knee compartment through knee flexion to a greater extent compared with lateral opening-wedge (LOW) DFO. Study Design: Controlled laboratory study. Methods: MCWHTO and LOWDFO were performed, correcting a mean of 8° of valgus alignment, in 10 cadaveric knees using plate fixation. Tibiofemoral contact pressure of the medial and lateral compartments was measured in 0°, 30°, 60°, and 90° of knee flexion before and after osteotomy using thin electronic sensors and load applied through an Instron device. PCP, MCP, and contact area were measured for each condition. Results: The lateral MCP was significantly decreased in the HTO state compared with the native state in 30° (P = .015), 60° (P = .0199), and 90° (P < .0001) of flexion. The lateral MCP was also significantly decreased in the HTO state when compared with the DFO state in 60° (P = .0093) and 90° of flexion (P < .0001). After DFO, the lateral MCP returned to that of the native state in 60° (P > .999) and 90° (P > .999) of flexion. The lateral PCP decreased for all test states in all degrees of flexion; the HTO state was significantly decreased when compared with the native state in 60° (P < .0001) and 90° (P < .0001). Conclusion: With varus corrections of 8°, MCWHTO was more effective at unloading the lateral compartment than LOWDFO. This effect was significant as the knee flexion angle increased. This study should be considered as one aspect of the surgical decision-making process. Clinical Relevance: In patients with mild to moderate valgus deformity without hypoplastic lateral femoral condyle and without significant joint line obliquity, MCWHTO may improve offloading of the lateral compartment in flexion.

Patient-Specific Instrumentation for Medial Closing Wedge Distal Femoral Osteotomy With Patellar Osteochondral Allograft.

The primary indications for performing a medial closing wedge distal femoral osteotomy are valgus knee malalignment, lateral knee compartment overload, lateral meniscus insufficiency, and/or lateral compartment osteoarthritis or cartilage damage. Without correction of this malalignment, there is an increased risk for chondral damage in the lateral and patellofemoral compartment of the knee. The optimal candidates for this procedure are young, active individuals with moderate to severe arthritis in the lateral compartment. Recently, preoperative planning for high tibial and distal femoral osteotomies (HTOs and DFOs) using 3-dimensional (3D) patient-specific instrumentation (PSI) has increased in popularity. Successful patient outcomes have been reported using this technique. This Technical Note illustrates our preferred technique that uses 3D PSI in addition to a patellar OCA transplant when treating a symptomatic cartilage lesion associated with genu valgum.

Republication of "Osteochondral Lesions of the Talus: Current Concepts in Diagnosis and Treatment".

Osteochondral lesions of the talus (OLTs) are a difficult pathologic entity to treat. They require a strong plan. Lesion size, location, chronicity, and characteristics such as displacement and the presence of subchondral cysts help dictate the appropriate treatment required to achieve a satisfactory result. In general, operative treatment is reserved for patients with displaced OLTs or for patients who have failed nonoperative treatment for 3 to 6 months. Operative treatments can be broken down into cartilage repair, replacement, and regenerative strategies. There are many promising treatment options, and research is needed to elucidate which are superior to minimize the morbidity from OLTs.

Data Science Enables the Development of a New Class of Chiral Phosphoric Acid Catalysts.

The widespread success of BINOL-chiral phosphoric acids (CPAs) has led to the development of several high molecular weight, sterically encumbered variants. Herein, we disclose an alternative, minimalistic chiral phosphoric acid backbone incorporating only a single instance of point chirality. Data science techniques were used to select a diverse training set of catalysts, which were benchmarked against the transfer hydrogenation of an 8-aminoquinoline. Using a univariate classification algorithm and multivariate linear regression, key catalyst features necessary for high levels of selectivity were deconvoluted, revealing a simple catalyst model capable of predicting selectivity for out-of-set catalysts. This workflow enabled extrapolation to a catalyst providing higher selectivity than both reported peptide-type and BINOL-type catalysts (up to 95:5 er). These techniques were then successfully applied towards two additional transforms. Taken together, these examples illustrate the power of combining rational design with data science (ab initio) to efficiently explore reactivity during catalyst development.

Latarjet Procedure to Restore Glenohumeral Stability in a Patient With a Postage Stamp Fracture.

The "postage stamp fracture" is an anterior glenoid rim fracture following arthroscopic repair of a Bankart lesion. Often occurring at the time of an acute trauma, a fracture line propagates though the previous Bankart repair anchor sites, resulting in recurrent anterior instability of the glenohumeral joint. The resultant glenoid rim fracture edge gives a similar appearance as the edge of a stamp, with the osseous edge having the classic "perforation" pattern. When patients present with a postage stamp fracture, even in the setting of subcritical glenoid bone loss, we believe that additional soft-tissue stabilization procedures and/or fracture fixation pose a significant risk of failure. In our opinion, a Latarjet procedure is recommended in a majority of patients with a postage stamp fracture for restoration of glenohumeral stability. The procedure offers a reliable, reproducible surgical intervention that controls for many of the factors that can make arthroscopic revision unreliable, such as poor bone quality, adhesions, labral degeneration, and bone loss. Here, we outline our preferred surgical technique to restore glenohumeral stability using the Latarjet procedure for a patient with a postage stamp fracture.

Treatment of the 'The Naked Humeral Head': Repair of Supraspinatus Avulsion, Subscapularis Tear, and Humeral Avulsion of the Glenohumeral Ligament.

A humeral avulsion of the glenohumeral ligament, or HAGL, lesion is a rare yet debilitating shoulder injury, which can lead to recurrent instability, pain, and overall shoulder dysfunction. The diagnosis is often difficult, requiring both high clinical suspicion, as well as identification on magnetic resonance imaging. In patients with an anterior HAGL, repair often requires an open approach. In extremely rare circumstances, the initial traumatic event that causes a HAGL can also cause disruption of the supraspinatus and subscapularis insertions on the humeral head. We have termed this the "naked humeral head". The purpose of this technical note is to describe our preferred technique to surgically treat the naked humeral head by repairing a supraspinatus avulsion fracture, HAGL lesion, and complete subscapularis tear.

Talar Allograft Preparation for Treatment of Reverse Hill-Sachs Defect in Recurrent Posterior Shoulder Instability.

Reverse Hill-Sachs lesions (rHSLs) after chronic posterior shoulder instability are important to recognize and treat appropriately. Treatment options for posterior instability with rHSL in the current literature are primarily based on percentage of humeral bone loss. In cases of moderate (25% to 50%) anterolateral humeral head bone loss, fresh osteochondral allografts are preferred. Recent literature has indicated that the talus serves as a robust grafting alternative site for the humeral head, as the talar dome shows high congruency and offers variable sizes. The purpose of this Technical Note is, therefore, to describe our technique for talus allograft preparation for the treatment of a large rHSL that highlights precise cutting anatomy, sizing options, and use of orthobiologics to ensure excellent talus union to the native humeral head surface.

Arthroscopic Treatment of Snapping Scapula Syndrome With Scapulothoracic Bursectomy and Partial Scapulectomy.

Snapping scapula syndrome (SSS) is a painful and debilitating condition that occurs as a result of disruption of normal scapulothoracic articulation and inflammation of numerous soft tissue and bursal structures that function to facilitate scapulothoracic motion. Historically, when nonoperative management of SSS failed, patients progressed to open surgical management. However, as arthroscopic techniques have evolved, the condition has been increasingly treated arthroscopically because of the minimally invasive nature, periscapular muscle-preserving approach with decreased risk to surrounding neurovascular structures, better intraoperative visualization, and quicker patient recovery and rehabilitation. The objective of this Technical Note is to describe our arthroscopic approach for the management of SSS using two portals to complete a scapulothoracic bursectomy and partial scapulectomy of the superomedial scapula. Level of Evidence: Level I: shoulder.

Iatrogenic Injury to the Suprascapular Nerve Following Reverse Shoulder Arthroplasty: A Case Report.

The location and course of the suprascapular nerve (SSN) to the glenohumeral joint places this nerve at risk when operating around the shoulder. Iatrogenic injury to the suprascapular nerve has been described in several different procedures including, rotator cuff repairs, posterior capsulorraphy, Bankart repairs, SLAP lesion repairs, Latarjet procedures, and shoulder arthroplasty. We present a case of iatrogenic suprascapular nerve injury due to superior glenoid baseplate screw placement following primary reverse shoulder arthroplasty (RSA), a novel approach to diagnosis of nerve injury, and treatment.

Comparison of computed tomography and 3D magnetic resonance imaging in evaluating glenohumeral instability bone loss.

BACKGROUND: To determine whether the addition of 3-dimensional (3D) magnetic resonance imaging (MRI) to standard MRI sequences is comparable to 3D computed tomographic (CT) scan evaluation of glenoid and humeral bone loss in glenohumeral instability. METHODS: Eighteen patients who presented with glenohumeral instability were prospectively enrolled and received both MRI and CT within 1 week of each other. The MRI included an additional sequence (volumetric interpolated breath-hold examination [VIBE]) that underwent postprocessing for reformations. The addition of a VIBE protocol, on average, is an additional 4-4.5 minutes in the scanner. CT data also underwent 3D postprocessing, and therefore each patient had 4 imaging modalities (2D CT, 2D MRI, 3D CT reformats, and 3D MRI reformats). Each sequence underwent the following measurements from 2 separate reviewers: glenoid defect, glenoid defect percentage, humeral defect, humeral defect percentage, and evaluation of glenoid track and version. Paired t tests were used to assess differences between imaging modalities and χ2 for glenoid track. Intra- and interobserver reliability were evaluated. Bland-Altman tests were also performed to assess the agreement between CT and MRI. In addition, we determined the cost of each imaging modality at our institution. RESULTS: 3D MRI measurements for glenoid and humeral bone loss measurements were comparable to 3D CT (Table 1). There were no significant differences for glenoid defect size and percentage, or humeral defect size and percentage (P > .05) (Table 2). Bland-Altman analysis demonstrated strong agreement, with small measurement errors for 3D CT and 3D MRI percentage glenoid bone loss. There was also no difference in evaluation for determining on vs. off track between any of the imaging modalities. Inter- and intrarater reliability was good to excellent for all CT and MRI measurements (r ≥ 0.7). CONCLUSION: 3D MRI measurements for bone loss in glenohumeral instability through use of VIBE sequence were equivalent to 3D CT. At our institution, undergoing MRI with 3D reconstruction was 1.67 times cheaper than MRI and CT with 3D reconstructions. 3D MRI may be a useful adjuvant to standard MRI sequences to allow concurrent soft tissue and accurate assessment of glenoid and humeral bone loss in glenohumeral instability.

Fresh Distal Tibial Allograft: An Updated Graft Preparation Technique for Anterior Shoulder Instability.

Fresh distal tibia allograft (DTA) has been gaining popularity among surgeons as an anatomic reconstruction option for the treatment of significant glenoid bone loss. Fresh DTA results in a clinically stable joint with excellent clinical outcomes and minimal graft resorption, and it has similar outcomes as the Latarjet procedure. Proper graft preparation and fixation are critical to ensuring optimal outcomes. The purpose of this Technical Note is, therefore, to describe our updated technique for DTA preparation that highlights precise cutting anatomy, sizing options, and use of orthobiologics to optimize distal tibia graft union to the native glenoid surface.

Primary Distal Tibia Allograft for Restoration of Glenohumeral Stability with Anterior Glenoid Bone Loss.

Recurrent shoulder instability with glenoid bone deficiency remains an increasing risk for failed shoulder stabilization surgery. Numerous free bone block procedures for primary treatment of anterior shoulder stability have been introduced as an alternative for the Latarjet procedure, including both autografts and allografts. Among such options is the fresh distal tibial allograft (DTA), a dense weightbearing bone without donor site morbidity and excellent conformity to the native glenoid. The aim of this Technical Note is therefore to describe our surgical technique for use of fresh DTA as a free bone block choice in the setting of primary anterior glenoid reconstruction in a patient with recurrent shoulder instability.

Arthroscopic Rotator Cuff Repair and Subpectoral Biceps Tenodesis in the Lateral Decubitus Position.

Arthroscopic rotator cuff repair can be performed with the patient in the beach-chair or lateral decubitus position. Patient positioning in shoulder arthroscopy is a critical step in surgical preparation and remains a debated topic. The lateral decubitus position is a reliable, safe, and effective position in which to perform nearly all types of shoulder arthroscopic procedures. The purpose of this Technical Note is to describe our preferred technique for performing arthroscopic rotator cuff repair with the patient in the lateral decubitus position, which portends several advantages, such as improved visualization of the glenohumeral space, ergonomic positioning, a low risk of cerebral hypoperfusion, and a shorter operating time.

Carbon Atom Insertion into Pyrroles and Indoles Promoted by Chlorodiazirines.

Herein, we report a reaction that selectively generates 3-arylpyridine and quinoline motifs by inserting aryl carbynyl cation equivalents into pyrrole and indole cores, respectively. By employing α-chlorodiazirines as thermal precursors to the corresponding chlorocarbenes, the traditional haloform-based protocol central to the parent Ciamician-Dennstedt rearrangement can be modified to directly afford 3-(hetero)arylpyridines and quinolines. Chlorodiazirines are conveniently prepared in a single step by oxidation of commercially available amidinium salts. Selectivity as a function of pyrrole substitution pattern was examined, and a predictive model based on steric effects is put forward, with DFT calculations supporting a selectivity-determining cyclopropanation step. Computations surprisingly indicate that the stereochemistry of cyclopropanation is of little consequence to the subsequent electrocyclic ring opening that forges the pyridine core, due to a compensatory homoaromatic stabilization that counterbalances orbital-controlled torquoselectivity effects. The utility of this skeletal transform is further demonstrated through the preparation of quinolinophanes and the skeletal editing of pharmaceutically relevant pyrroles.

Arthroscopic Double-Row Bony Bankart Bridge Repair Using a Tensionable Knotless System.

Posterior labral pathology is common in contact athletes; however, posterior glenoid avulsion fractures, also known as posterior bony Bankart lesions, are less common. Posterior instability affects approximately 10% of all patients with shoulder instability. Diagnosis in these high-risk individuals often follows a traumatic posterior dislocation. The patient feels grossly unstable but may or may not have recurrent dislocations beyond the initial trauma. Surgical correction and favorable surgical outcomes require a full understanding of both the soft-tissue and bony components of the injury. Stable osseous fixation is required to restore appropriate glenoid version, depth, and to prevent malunion. We present a technique to mobilize and stabilize a posterior bony Bankart lesion with a knotless suture bridge construct. We feel that this technique is reliable and reproducible and allows for a superior quality of fragment reduction when compared with systems using larger anchors and knotted systems.

The Intrarater and Inter-rater Reliability of Radiographic Evaluation of the Posterior Tibial Slope in Pediatric Patients.

BACKGROUND: In young athletes, an association exists between an increased posterior tibial slope (PTS) and the risk of primary anterior cruciate ligament (ACL) injury, ACL graft rupture, contralateral ACL injury, and inferior patient reported outcomes after ACL reconstruction. In spite of this, there is no consensus on the optimal measurement method for PTS in pediatric patients. The purpose of this study was to evaluate the reliability of previously described radiographic PTS measurement techniques. METHODS: A retrospective review was performed on 130 patients with uninjured knees between the ages of 6 and 18 years. The medial PTS was measured on lateral knee radiographs by four blinded reviewers using three previously described methods: the anterior tibial cortex (ATC), posterior tibial cortex (PTC), and the proximal tibia anatomic axis (PTAA). The radiographs were graded by each reviewer twice, performed 2 weeks apart. The intrarater and inter-rater reliability were assessed using the intraclass correlation coefficient (ICC). Subgroup analyses were then performed stratifying by patient age and sex. RESULTS: The mean PTS were significantly different based on measurement method: 12.5 degrees [confidence interval (CI): 12.2-12.9 degrees] for ATC, 7.6 degrees (CI: 7.3-7.9 degrees) for PTC, and 9.3 degrees (CI: 9.0-9.6 degrees) for PTAA (P<0.0001). Measures of intrarater reliability was excellent among all reviewers across all 3 methods of measuring the PTS with a mean ICC of 0.87 (range: 0.82 to 0.92) for ATC, 0.83 (range: 0.82 to 0.87) for PTC, and 0.88 (range: 0.79 to 0.92) for PTAA. The inter-rater reliability was good with a mean ICC of 0.69 (range: 0.62 to 0.83) for the ATC, 0.63 (range: 0.52 to 0.83) for the PTC, and 0.62 (range: 0.37 to 0.84) for the PTAA. Using PTAA referencing, the PTS was greater for older patients: 9.9 degrees (CI: 7.7-9.4 degrees) vs 8.5 degrees (CI: 9.2-10.7 degrees) (P=0.0157) and unaffected by sex: 9.5 degrees (CI: 8.8-10.1 degrees) for females and 9.0 degrees (CI: 8.0-10.0) for males (P=0.4199). There were no major differences in intrarater or inter-rater reliability based on age or sex. CONCLUSIONS: While the absolute PTS value varies by measurement technique, all methods demonstrated an intrarater reliability of 0.83 to 0.88 and inter-rater reliability of 0.61 to 0.69. However, this study highlights the need to identify PTS metrics in children with increased inter-rater reliability. LEVEL OF EVIDENCE: IV, Case series.

In Response to COVID-19: Current Trends in Orthopaedic Surgery Sports Medicine Fellowships.

BACKGROUND: The COVID-19 (SARS-COV-2) pandemic has brought unprecedented challenges to the health care system and education models. The reduction in case volume, transition to remote learning, lack of sports coverage opportunities, and decreased clinical interactions have had an immediate effect on orthopaedic sports medicine fellowship programs. PURPOSE/HYPOTHESIS: Our purpose was to gauge the response to the pandemic from a sports medicine fellowship education perspective. We hypothesized that (1) the COVID-19 pandemic has caused a significant change in training programs, (2) in-person surgical skills training and didactic learning would be substituted with virtual learning, and (3) hands-on surgical training and case numbers would decrease and the percentage of fellows graduating with skill levels commensurate with graduation would decrease. STUDY DESIGN: Cross-sectional study. METHODS: In May 2020, a survey was sent to the fellowship directors of all 90 orthopaedic sports medicine fellowships accredited by the Accreditation Council for Graduate Medical Education; it included questions on program characteristics, educational lectures, and surgical skills. A total of 37 completed surveys (41%) were returned, all of which were deidentified. Responses were compiled and saved on a closed, protected institutional server. RESULTS: In a majority of responding programs (89%), fellows continued to participate in the operating room. Fellows continued with in-person clinical visits in 65% of programs, while 51% had their fellows participate in telehealth visits. Fellows were "redeployed" to help triage and assist with off-service needs in 21% of programs compared with 65% of resident programs having residents rotate off service. Regarding virtual education, 78% of programs have used or are planning to use platforms offered by medical societies, and 49% have used or are planning to use third-party independent education platforms. Of the 37 programs, 30 reported no in-person lectures or meetings, and there was a sharp decline in the number of programs participating in cadaver laboratories (n = 10; 27%) and industry courses (n = 6; 16%). CONCLUSION: Virtual didactic and surgical education and training as well as telehealth will play a larger role in the coming year than in the past. There are effects to fellows' exposure to sports coverage and employment opportunities. The biggest challenge will be how to maintain the element of human interaction and connect with patients and trainees at a time when social distancing is needed to curb the spread of COVID-19.

Transphyseal Anterior Cruciate Ligament Reconstruction Using Hybrid Transtibial Femoral Drilling and a Quadriceps Tendon Autograft.

Significant controversy exists regarding the optimal surgical technique for anterior cruciate ligament (ACL) reconstruction in adolescents with 1 to 3 years of skeletal growth remaining. Graft choice and physeal injury remain primary concerns given significantly elevated rates of failure of hamstring autograft reconstructions in this population, as well as risks of leg-length discrepancy and growth axis deviation. Traditional (more vertical) transtibial drilling of the femoral tunnel can reduce risks of physeal injury but has been shown to have less accuracy restoring the native femoral ACL footprint and associated incomplete knee stabilization. On the other hand, anteromedial and outside-in drilling yields improvements in the tunnel location and biomechanics but at the cost of a more oblique trajectory and greater risk of physeal injury. A hybrid transtibial pin technique using a Pathfinder guide facilitates femoral drilling with the "best of both worlds," allowing for reproduction of the native ACL footprint and a more physeal-respecting femoral tunnel. When combined with an all-soft tissue quadriceps tendon autograft and suspensory fixation, the hybrid transtibial method yields a reliable, safe, and robust construct with promising results for the young athlete. We describe our preferred graft harvest, tunnel drilling, and fixation techniques to minimize physeal risks and optimize outcomes.

Anchor-Based Femoral Fixation for Physeal-Sparing Medial Patellofemoral Ligament Reconstruction: A Time-Zero Biomechanical Comparison With Tenodesis Screw Fixation.

BACKGROUND: Open physes and trochlear/notch geometries in pediatric patients limit the safe corridor for femoral interference screw graft fixation during medial patellofemoral ligament (MPFL) reconstruction. Accordingly, interest is increasing in anchor-based fixation, but biomechanical validation is deficient. PURPOSE: To compare anchor-based and tenodesis screw femoral fixation of MPFL grafts in a time-zero biomechanical model. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-seven fresh-frozen porcine distal femurs were potted for testing in an electromechanical load frame, while bovine tendons were used for MPFL grafts. Reconstructions were performed with 1 of 3 femoral fixation strategies: 4.5-mm biocomposite double-loaded threaded anchor (DLA group), 3.9-mm biocomposite knotless threaded anchor (KA group), or traditional 7 × 23-mm biocomposite tenodesis screw (TS group). For testing, femoral specimens were oriented and secured in the mechanical testing apparatus such that actuator tensile pull re-created the normal MPFL trajectory. Specimens underwent 10 cycles of 5- to 15-N loading at 1-Hz preconditioning, followed by 1000 cycles of 10- to 50 N-loading at 1 Hz. After cyclic loading, all specimens were loaded to failure at 305 mm/min. The average cyclic construct stiffness, displacement, and load-to-failure data between the 3 groups were compared using analysis of variance (ANOVA) with the significance level set at P < .05. RESULTS: Average cyclic construct stiffnesses were comparable across groups per repeated-measures ANOVA analysis: 68.3 ± 6.3, 71.4 ± 6.4, and 74.3 ± 7.9 N/mm for TS, DLA, and KA groups, respectively (at cycle 1000). Average construct displacements at cycles 100 and 1000 were significantly less in the anchor versus tenodesis screw groups per ANOVA and Tukey post hoc analysis: 7.7 ± 4.2 mm for the TS group versus 3.7 ± 0.4 and 4.3 ± 0.6 mm for the DLA and KA groups, respectively (at cycle 1000). There was no significant difference in ultimate failure loads between the anchor and tenodesis screw groups, but 3 of 9 TS constructs failed at loads below the average failure load of the native MPFL. CONCLUSION: Compared with the tenodesis group, anchor-based fixation produced constructs with equivalent cyclic stiffnesses, improved load-displacement characteristics, and had less failure load variability in the porcine cadaveric model. CLINICAL RELEVANCE: Femoral fixation of the MPFL graft with a single anchor (4.5 or 3.9 mm threaded) is a viable alternative to traditional tenodesis screw fixation.

Physeal-Sparing Medial Patellofemoral Ligament Reconstruction With Suture Anchor for Femoral Graft Fixation.

Patellar instability is a common problem in the active pediatric population. When nonoperative treatment of the instability fails, growth-respecting surgical stabilization techniques are required. As the incidence of medial patellofemoral ligament (MPFL) reconstruction has increased, techniques have improved to avoid physeal injury to the distal femur. These techniques are technically demanding because of the small size of the distal femoral epiphysis in children, as well as the relatively large socket size (7-8 mm in diameter, >20 mm in length) required for sound fixation with a tenodesis screw as originally described. The size of the femoral tunnel for interference fixation puts the surrounding structures at risk of damage. We present a modification of the epiphyseal socket technique for anatomic growth-sparing MPFL reconstruction using a small soft anchor for femoral graft fixation. This has the proposed advantages of diminishing volumetric bony removal from the epiphysis; increasing the margin of safety with respect to notch, trochlear, and/or physeal damage; and reducing the risk of thermal damage to the physis during socket reaming. This technique is technically simple and can be easily learned by surgeons familiar with adult MPFL reconstruction techniques.