Relative Energy Deficiency in Sport (RED-S) and Knee Injuries: Current Concepts for Female Athletes

In athletes, a mismatch between caloric intake and energy expended in exercise can result in Low Energy Availability (LEA). LEA can lead to Relative Energy Deficiency in Sport (RED-S), where the athlete suffers from physiological derangements and decreased sport performance. The prevalence of RED-S is higher in females than males. RED-S more comprehensively describes the syndrome originally known as "Female Athlete Triad" (FAT). FAT encompasses the triad of LEA (with or without disordered eating), menstrual dysfunction and low bone mineral density. RED-S includes other physiological derangements such as poor cardiovascular health, abnormalities of metabolic rate, immunity, and protein synthesis. Females are already at a higher risk of knee injuries, which has been attributed to a multitude of factors such as hormonal influences, differences in musculoskeletal anatomy and neuromuscular control compared to males. The literature demonstrates an even higher risk of knee injuries in female athletes with symptoms of RED-S. We propose the various factors that influence this risk. A reduction in anabolic hormones can affect muscle development and tendon repair. A relationship between poor neuromuscular control and knee injury has been established, and this can be further worsened in patients with menstrual dysfunction. Chronic deficiency in nutrients such as collagen and vitamin D can result in poorer recovery from microtrauma in tendon and ligaments. All these factors may contribute to increasing the risk of knee injuries, which may include anterior cruciate ligament tears, patella tendinopathy and patellofemoral pain syndrome. This review aims to educate sports clinicians to have a high index of suspicion when treating knee injuries in females; to screen and then manage for RED-S if present, for holistic patient care.

Patellofemoral instability part 1 (When to operate and soft tissue procedures): State of the art

Patellofemoral instability is usually initially treated non-operatively. Surgery is considered in patients with recurrent patellar dislocation, and after a first-time patellar dislocation in the presence of either an associated osteochondral fracture or high risk of recurrence. Stratifying the risk of recurrence includes evaluating risk factors such as age, trochlear dysplasia, contralateral dislocation and patellar height. Surgery with soft tissue procedures include restoring the medial patellar restraints and balancing the lateral side of the joint. Reconstruction of the medial patellofemoral ligament is the most frequent way of addressing the medial soft tissues in patients with patellofemoral instability. Meanwhile, lateral tightness can be achieved by lateral retinaculum lengthening or release. Approaching patellofemoral instability in a patient-specific approach, combined with a shared decision-making process with the patient/family, will guide surgeons to the deliver optimal care for the patellar instability patient.

Editorial Commentary: Diverse Factors Affect Measurement of Patella Alta: Trochlear Morphology and Sagittal Knee Balance Represent Defining Factors of Patellofemoral Stability

Patella alta is a known risk factor for patellar instability, contributing to increased length changes of the medial patellofemoral complex, and associated with high rates of failure after medial patellofemoral complex reconstruction. Distalization through tibial tuberosity osteotomy (TTO) is a surgical option to address patella alta during patellar stabilization surgery. However, distalization has been shown to have greater complication rates than other types of TTO, and therefore precise indications through proper assessments of patellar height are needed. The Caton-Deschamps index is a commonly used measurement and is independent of patellar tendon length, allowing for assessment of patellar height before and after distalizing TTO. Additional options that may offer this ability are femoral-based measurements such as the patellotrochlear index and sagittal patellar engagement, which also do not rely on the position of the tubercle and may better represent the functional engagement of the patellofemoral joint. However, femoral-based measurements depend on trochlear morphology; theoretically, an advantage of femoral-based measurements is that they may reflect the functional engagement of the patella within the trochlea. However, in knowing the common relation between patella alta and trochlear dysplasia, the question becomes whether an overlap between the patella and a dysplastic proximal trochlea on a sagittal measurement truly represents functional engagement and stability of the patellofemoral joint. Measurement of patella alta and determining indications for distalization can be influenced by measurement techniques including magnetic resonance imaging versus radiography, tibial- versus femoral-based measurements, and positional and morphologic considerations. Increased understanding of trochlear morphology and sagittal knee balance as they relate to patella alta will be important for defining the factors that affect patellofemoral stability.

How Mental Health Affects Injury Risk and Outcomes in Athletes

CONTEXT

The importance of mental health among athletes is becoming more recognized and valued. Athletes experience symptoms of depression, anxiety, and related mental health disorders at rates similar to those of the general population, but because athletes face unique cultural and environmental pressures, such disorders are exacerbated in the context of an injury. Furthermore, we review the less well-known evidence that mental health disorders in athletes are associated with an increased risk of injury. We discuss the increasing awareness of the deficiencies in mental health support for athletes, which has been especially highlighted during the COVID-19 pandemic as well as in prominent professional and Olympic athletes, and describe both internal and external barriers to appropriate care.

EVIDENCE ACQUISITION

We searched PubMed for pertinent peer-reviewed studies.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

There is a known psychological response to injury that can prolong recovery from musculoskeletal injury; conversely, mental health disorders in athletes are not only associated with an increased injury risk but also portend poorer outcomes subsequently, including prolonged recovery times, increased rates of injury recurrence, decreased rates of return to sport, and reduced performance upon return. Because of inherent barriers to appropriate care of athletes, including identification, stigma, and resource availability, there are currently various ongoing efforts nationally to create and implement initiatives regarding athlete mental health screening, support systems, and directed interventions to address the inextricably linked physical and mental health of athletes.

CONCLUSION

Athletic injury negatively impacts the mental health of athletes. Likewise, mental health can and does influence athletic performance and is also intimately tied to the risk of athletic injury, thus creating a complex cycle with inability to separate physical and mental health.

Evaluation of Differences in Patellar Height After Patellar Stabilization Procedures Not Intended to Address Patella Alta: A Multicenter Study

Background

Recent studies have reported conflicting results as to whether isolated medial patellofemoral ligament reconstruction (MPFLr) leads to decreased patellar height.

Purpose

To investigate if patellar stabilization surgery not intended to address patella alta influences patellar height.

Study Design

Cohort study; Level of evidence, 3.

Methods

A multicenter retrospective chart review was conducted, and patients who underwent MPFLr, medializing tibial tuberosity osteotomy (TTO), and/or trochleoplasty between 2016 and 2020 were included. The Caton-Deschamps index (CDI) was calculated from radiographs obtained preoperatively, 2 weeks postoperatively, and 3 months postoperatively. The preoperative CDI value was compared with the 2-week postoperative and 3-month postoperative values according to stabilization procedure (isolated MPFLr, isolated TTO, MPFLr + TTO, MPFLr + trochleoplasty, and MPFLr + trochleoplasty + TTO) using the paired t test. Analyses of the 1-bundle versus 2-bundle MPFLr technique and the presence of lateral retinacular release or lateral retinacular lengthening were conducted on the isolated MPFLr and combined MPFLr + TTO cohorts.

Results

A total of 356 knees were included. Statistically significant pre- to postoperative decreases in CDI were seen in all stabilization procedures analyzed (P≤ .017 for all). Within the isolated MPFLr cohort, this significant decrease was seen at 2 weeks postoperatively with the 2-bundle technique (ΔCDI = -0.09; P < .001) but not with the 1-bundle technique (ΔCDI = -0.01; P = .621).

Conclusion

The different surgical techniques analyzed in the current study affected patellar height, even when a distalizing TTO was not performed. The decrease was dependent on surgical technique, with a 2-bundle MPFLr leading to a statistically significant decrease and a 1-bundle MPFLr effecting no change.

Hemoglobin A1c Levels >6.6% Are Associated With Higher Postoperative Complications After Anterior Cruciate Ligament Reconstruction

Purpose

To investigate the relation between hemoglobin A1c (HbA1c) levels and postoperative complications after primary anterior cruciate ligament reconstruction (ACLR).

Methods

A retrospective review was performed of consecutive patients with an isolated anterior cruciate ligament tear, preoperative diagnosis of diabetes, and documented HbA1c within 90 days of primary ACLR between 2000 and 2019. Data collected included demographic and surgical characteristics, 90-day medical complications, and subsequent surgeries on the ipsilateral knee. A receiver operating curve was constructed for each HbA1c level in relation to postoperative complications and the optimal cutoff identified via Youden's J statistic. Multivariable logistic regression was performed to assess the relation between postoperative complications and age, sex, graft type, diabetes subtype, and HbA1c.

Results

Nineteen patients (7 females, 12 males) fulfilled inclusion criteria with preoperative HbA1c ranging from 5.5 to 10. Complications included septic knee (n = 1) and cyclops lesions requiring arthroscopic lysis (n = 3). Patients with HbA1c of 6.7% or higher were 25 times more likely to experience any postoperative complication (P = .04) and 16 times more likely to require lysis of adhesions (P = .08). On multivariable regression, HbA1c remained significantly associated with any complication (P = .005) and developing arthrofibrosis (P = .02) independent of age, sex, graft type, and diabetes subtype.

Conclusions

Diabetic patients undergoing primary ACLR with a preoperative HbA1c of 6.7% or higher were 25 times more likely to require repeat surgical intervention for a postoperative complication. These complications included arthrofibrosis and infection. Strict glycemic control may help minimize the risk of postoperative complications after ACLR.

Level of Evidence

Level III, retrospective cohort study.

Telemedicine After COVID-19: Incorporating Virtual Visits Into Your Practice

The use of telemedicine services within orthopaedics increased rapidly as a result of the COVID-19 pandemic. Telemedicine may improve access to care and save time and money for patients and clinicians; however, limitations such as technical issues and limited physical examination may reduce its widespread adoption. Virtual visits generally produce equivalent satisfaction and clinical outcomes compared with those performed in person. Although telemedicine has served many different roles within orthopaedic practices, its main utility is for patients who have to travel significant distances and for visits that do not require physical examination to determine a treatment plan. Several regulations govern the use of telemedicine. Most notably, clinicians must be licensed to practice medicine in the state in which the patient is located during the appointment. Although compliance issues remain a potential source of legal issues, experts cite misdiagnosis from limited physical examination as the most likely reason for medical liability. Clinicians should be familiar with techniques for virtual physical examination and should provide instruction to patients before the visit to optimize data obtained.

Location and Progression of Chondral Injuries at the Time of Revision ACL Surgery Varies by Sex

PURPOSE

To quantify progression of chondral and meniscal injuries between primary and revision anterior cruciate ligament (ACL) surgery.

METHODS

Patients who underwent both index and revision ACL reconstruction between 2000 and 2020 at our institution were identified, and dates of injury and surgery, demographics, and clinical data were obtained from operative reports. Outerbridge grade was recorded in each compartment, along with presence and location of meniscal injury. The frequency of each injury between first and second cases was calculated. Differences in injury and progression were compared over time as well as between patient sex and age.

RESULTS

The study included 189 patients (96 female, 93 male). Age at first surgery was 31.7 ± 13.2 years. Mean time to second injury was 3.3 ± 3.0 years. In total, 116 patients had a new or previous chondral injury (odds ratio, 1.6; 95% CI, 1.2-2.1). The medial femoral condyle (31%) and the patella (21%) accounted for the highest proportion of new injury to articular surfaces, whereas new injury to menisci was comparable between the medial (25%) and lateral (23%) meniscus. At the time of revision ACL reconstruction, females had a high prevalence of chondral injuries to the lateral compartment, whereas males had a high prevalence of chondral injury to the medial femoral condyle. The prevalence of new chondral injuries was comparable between sexes, with males having a slightly higher proportion. While time between surgeries, sex, and age had graphical evidence of moderating risk, the effects were small and imprecise.

CONCLUSIONS

Revision ACL reconstruction carried a 1.6 increase in the odds for new or progressive chondral lesions in our cohort. At the time of revision, females had a relatively higher proportion of lateral-sided chondral injuries, whereas males had a relatively higher proportion of medial femoral condyle injuries. The greatest increase in the prevalence of new and progressive lesions was observed in the medial femoral condyle and trochlea. This progression appeared to be moderated by time between surgeries, patient sex, and age; however, the differences were small and imprecise.

STUDY DESIGN

Level IV, therapeutic case series.

Radiographic Landmark Measurements for the Femoral Footprint of the Medial Patellofemoral Complex May Be Affected by Visible Femoral Shaft Length on Lateral Knee Radiographs

PURPOSE

To assess the effect of visible femoral shaft length on the accuracy of radiographic landmarks of the medial patellofemoral complex (MPFC).

METHODS

In 9 cadaveric knees, the MPFC footprint was exposed on the medial femur, and its proximal and distal boundaries were marked. Lateral fluoroscopic images of the knee were assessed in 1-cm length increments, beginning 1 cm proximal to the medial condyle and continuing proximally to 8 cm. The MPFC midpoint was described on each image relative to the posterior cortical line of the femur and a line perpendicular to this line through the proximal margin of the medial condyle. In addition, the MPFC midpoint was assessed relative to a line from the proximal posterior cortex to the midpoint of Blumensaat line.

RESULTS

Using the posterior cortical line as a reference, the MPFC radiographic landmark moved anteriorly with decreasing visible femoral shaft on radiographs, particularly at 4 cm and less. However, no proximal-distal change was noted. Linear regression analysis demonstrated a relationship between visible femoral shaft and MPFC position on radiographs (R = 0.461, R2 = 0.212, B = -0.636, P < .001). For every centimeter decrease in the visible femoral shaft, the radiographic MPFC footprint moved anteriorly by 0.636 mm. Receiver operating characteristic curve analysis revealed that a minimum of 4 cm of femoral shaft on lateral radiographs is required for accurate MPFC footprint localization (area under the curve = 0.80; sensitivity = 76.7%; specificity = 69.0%; P < .001). In contrast, no anterior-posterior change was seen when referencing a line from the proximal posterior cortex to the midpoint of Blumensaat line.

CONCLUSIONS

When using the posterior cortical line to identify the midpoint of the MPFC, at least 4 cm of femoral shaft should be visible for accurate assessment. If less than 4 cm of shaft is visible, a line through the midpoint of Blumensaat line and the proximal posterior cortex can be used as an alternative method to estimate the position of the femoral footprint.

CLINICAL RELEVANCE

As fluoroscopy is frequently used intraoperatively for MPFC reconstruction, our findings may serve as a guide when assessing femoral tunnel placement on fluoroscopy.

A modified Delphi consensus statement on patellar instability: part II

Aims

The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

Methods

This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered unanimous.

Results

Of 41 questions and statements on patellar instability, none achieved unanimous consensus, 19 achieved strong consensus, 15 achieved consensus, and seven did not achieve consensus.

Conclusion

Most statements reached some degree of consensus, without any achieving unanimous consensus. There was no consensus on the use of anchors in MPFL reconstruction, and the order of fixation of the graft (patella first versus femur first). There was also no consensus on the indications for trochleoplasty or its effect on the viability of the cartilage after elevation of the osteochondral flap. There was also no consensus on postoperative immobilization or weightbearing, or whether paediatric patients should avoid an early return to sport.

A modified Delphi consensus statement on patellar instability: part I

Aims

The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Methods

A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered to be unanimous.

Results

Of 27 questions and statements on patellar instability, three achieved unanimous consensus, 14 achieved strong consensus, five achieved consensus, and five did not achieve consensus.

Conclusion

The statements that reached unanimous consensus were that an assessment of physeal status is critical for paediatric patients with patellar instability. There was also unanimous consensus on early mobilization and resistance training following nonoperative management once there is no apprehension. The statements that did not achieve consensus were on the importance of immobilization of the knee, the use of orthobiologics in nonoperative management, the indications for MPFC repair, and whether a vastus medialis oblique advancement should be performed.

Adding Tibial Tuberosity Medialization to Medial Patellofemoral Ligament Reconstruction Reduces Lateral Patellar Maltracking During Multidirectional Motion in a Computational Simulation Model

Purpose

To determine whether adding tibial tuberosity medialization to medial patellofemoral ligament (MPFL) reconstruction reduces lateral patellar maltracking during a dynamic multidirectional activity and to investigate when medial patellofemoral contact pressures are elevated during daily activities, such as squatting.

Methods

Seven computational models representing knees with patellar instability, including lateral patellar maltracking, were evaluated following simulated MPFL reconstruction (bisect offset index > .75). Tibial tuberosity medialization was added to MPFL reconstruction for each model. Patellar tracking during multidirectional motion was evaluated by simulating pivot landing. Analysis of pivoting focused on early flexion (5° to 40°). Patellofemoral contact pressures during daily function were evaluated by simulating knee squatting. Data were analyzed with paired comparisons between MPFL reconstruction with and without tuberosity medialization.

Results

The patella dislocated during pivoting for 2 models with an isolated MPFL reconstruction and for 1 model including tibial tuberosity medialization. Adding tibial tuberosity medialization to MPFL reconstruction significantly decreased bisect offset index by ∼0.1 from 5° to 40° (P < .03). For knee squatting, medializing the tibial tuberosity significantly increased maximum medial contract pressure by ∼0.5 MPa from 30° to 85° (P < .05) but did not significantly influence maximum lateral pressure.

Conclusions

In this study of simulated multidirectional motion, MPFL reconstruction did not sufficiently constrain the patella for some knees. Adding tibial tuberosity medialization to MPFL reconstruction in these models reduced lateral patellar maltracking during multidirectional motion but increased pressure applied to medial cartilage during squatting.

Clinical Relevance

After establishing the influence of tibial tuberosity medialization on patellar maltracking for an idealized population, as was done in the current study, future simulation studies can be performed to better determine the anatomical characteristics of patients for whom tibial tuberosity medialization is needed to reduce the risk of postoperative patellar maltracking.

Team Approach: Improving Orthopaedic Operating Room Efficiency

The cost of surgical care accounts for almost one-third of all health care spending in the United States. Within health care spending, the operating room (OR) is one of the largest health care costs during a perioperative episode of care. Efficiency in the OR has been associated with increased productivity, safety, and quality of care. However, multiple sources of delays can contribute to inefficiency, and improving efficiency in the OR requires a systematic approach to identify and address each issue. We report on the case of a process improvement initiative implemented in a large academic institution to improve OR efficiency in outpatient orthopaedic cases, and we discuss the lessons learned through this program. Optimizing workflow in the OR requires a multidisciplinary team approach consisting of clinician leaders with common goals and open discussion regarding the needs of each team member, including circulating nurses, surgical nurses/technologists, and anesthesiologists. Our experience highlights the importance of practical, clinician-driven changes that are supported by administrative engagement, resources for staffing and equipment, and institutional flexibility, which are required to implement systemic changes to address and improve efficiency in the OR.

Association of Trochlear Length on Sagittal MRI to Trochlear Dysplasia in Knees With Patellar Instability

Background

Trochlear dysplasia is a primary risk factor for patellar instability and leads to loss of the osteochondral constraint of the patella. Trochleoplasty techniques include the Peterson grooveplasty, which alters the length of the trochlea; however, a radiographic measurement of trochlear length to support this has not been described.

Purpose

To describe measurements to quantify trochlear length on sagittal magnetic resonance imaging in patients with and without patellar instability and to correlate trochlear length with measurements of trochlear dysplasia.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 66 age- and sex-matched knees (36 female and 30 male; mean age, 20.8 ± 4.8 years) were included in this study, of which 33 had patellar instability. Trochlear extension length (TEL) and trochlear alpha angle (TAA) were measured on 3 sagittal magnetic resonance imaging scans (center of the knee, center of the medial condyle, and center of the lateral condyle), and measurements were compared between symptomatic and control knees. Receiver operating characteristic curve analysis was performed, and the area under the curve (AUC) was calculated to describe the accuracy of each measurement to distinguish between knees with and without patellar instability. Linear and multivariate regression analyses were performed to assess the relationship between sagittal measurements and axial measurements of trochlear dysplasia, including lateral trochlear inclination, sulcus angle, and trochlear depth, as well as patient size reflected by the epicondylar distance.

Results

In symptomatic knees, the central trochlea extended more proximally than in control knees, as determined by the TEL (14.0 ± 3.0 vs 11.5 ± 2.3 mm, respectively; P < .001) and TAA (68.4° ± 3.8° vs 70.5° ± 3.4°, respectively; P = .017). AUC calculations showed that a TEL ≥11 mm at the central trochlea was predictive of patellar instability in both male and female knees (AUC = 0.83 and 0.77, respectively), as was a TAA ≤67° in female knees (AUC = 0.72). An independent association between the central TEL and sulcus angle was found. The central TEL showed a weak correlation with patient size, as measured by the epicondylar distance, while the TAA did not.

Conclusion

In knees with symptomatic patellar instability, the central trochlea was found to extend 2.5 mm more proximally than in control knees, and this increase in length correlated with severity of trochlear dysplasia. As radiographic examinations of the trochlea and grooveplasty procedures are often based on the proximal extent of the cartilaginous trochlea, further studies are needed to identify the role of trochlear length in the assessment and treatment of trochlear dysplasia in the setting of patellar instability.

Medial Patellofemoral Reconstruction Techniques for Patellar Instability

The medial patellofemoral complex (MPFC) is the term used to describe the primary soft tissue stabilizer of the patella, which consists of fibers that attach to the patella (medial patellofemoral ligament, or MPFL), and the quadriceps tendon (medial quadriceps tendon femoral ligament, or MQTFL). Despite the variability of its attachment on the extensor mechanism, the midpoint of this complex is consistently at the junction of the medial quadriceps tendon with the articular surface of the patella, indicating that either patellar or quadriceps tendon fixation can be used for anatomic reconstruction. Multiple techniques exist to reconstruct the MPFC, including graft fixation on the patella, quadriceps tendon, or both structures. Various techniques using several graft types and fixation devices have all reported good outcomes. Regardless of the location of fixation on the extensor mechanism, elements critical to the success of the procedure include anatomic femoral tunnel placement, avoiding placing undue tension on the graft, and addressing concurrent morphological risk factors when present. This infographic reviews the anatomy and techniques for the reconstruction of the MPFC, including graft configuration, type, and fixation, while addressing common pearls and pitfalls in the surgical treatment of patellar instability.

In Vivo Length Changes Between the Attachments of the Medial Patellofemoral Complex Fibers in Knees With Anatomic Risk Factors for Patellar Instability

BACKGROUND

Medial patellofemoral complex (MPFC) reconstruction plays an important role in the surgical treatment of patellar instability. Anatomic reconstruction is critical in re-creating the native function of the ligament, which includes minimizing length changes that occur in early flexion. Anatomic risk factors for patellar instability such as trochlear dysplasia, patella alta, and increased tibial tuberosity to trochlear groove (TT-TG) distance have been shown to influence the function of the MPFC graft in cadaveric studies, but the native length change patterns of the MPFC fibers in knees with anatomic risk factors have not been described.

PURPOSE

To describe the in vivo length changes of the MPFC fibers in knees with anatomic risk factors for patellar instability and identify the optimal attachment sites for MPFC reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Dynamic computed tomography imaging was performed on the asymptomatic knee in patients with contralateral patellar instability. Three-dimensional digital knee models were created to assess knees between 0° and 50° of flexion in 10° increments. MPFC fiber lengths were calculated at each flexion angle between known anatomic attachment points on the extensor mechanism (quadriceps tendon, MPFC midpoint [M], and patella) and femur (1, 2, and 3, representing the proximal to distal femoral footprint). Changes in MPFC fiber length were compared for each condition and assessed for their relationships to morphologic risk factors (trochlear depth, Caton Deschamps Index [CDI], and TT-TG distance).

RESULTS

In 22 knees, native MPFC fibers were found to be longer at 0° than at 20° to 50° of flexion. Length changes observed between 0° and 50° increased with the number of risk factors present. In the central fibers of the MPFC (M-2), 1.7% ± 3.1% length change was noted in knees with no anatomic risk factors, which increased to 5.6% ± 4.6%, 17.0% ± 6.4%, and 26.7% ± 6.8% in the setting of 1, 2, and 3 risk factors, respectively. Nonanatomic patella-based attachments were more likely to demonstrate unfavorable length change patterns, in which length was greater at 50° than 0°. In patellar attachments, an independent relationship was found between increasing length changes and TT-TG distance, while in quadriceps tendon attachments, a trend toward a negative relationship between length changes and CDI was noted. All configurations demonstrated a strong relationship between percentage change in length and number of morphologic risk factors present, with the greatest influence found in patella-based attachments.

CONCLUSION

The MPFC fibers demonstrated increased length changes in knees when a greater number of morphological risk factors for patellar instability were present, which worsened in the setting of nonanatomic configurations. This suggests that the function of the intact MPFC in patients with anatomic risk factors may not reflect previously described findings in anatomically normal knees. Further studies are needed to understand the pathoanatomy related to these changes, as well as the implications for graft placement and assessment of length changes during MPFC reconstruction techniques.

CLINICAL RELEVANCE

MPFC length change patterns vary based on the number of morphologic risk factors for patellar instability present and should be considered during reconstructive procedures.

Redefining Trochlear Dysplasia: Normal Thresholds Vary by Measurement Technique, Landmarks, and Sex

BACKGROUND

Trochlear dysplasia is a known risk factor for patellar instability. Multiple radiographic measurements exist to assess trochlear morphology, but the optimal measurement technique and threshold for instability are unknown.

PURPOSE

To describe the optimal measurements and thresholds for trochlear dysplasia on magnetic resonance imaging (MRI) that can identify knees with patellar instability in male and female patients.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

Knee MRI scans of patients with patellar instability were compared with those of age- and sex-matched controls. Measurements of the sulcus angle, lateral trochlear inclination (LTI), and trochlear depth were performed on axial images using bony and cartilaginous landmarks. Receiver operating characteristic curve analysis was performed, with the area under the curve (AUC) describing the accuracy of each diagnostic test. Optimal cutoff values were calculated to distinguish between knees with and without patellar instability. AUC and cutoff values were reported for each measurement as well as for male and female subgroups.

RESULTS

A total of 238 knee MRI scans were included in this study (138 female, 100 male; age range, 18-39 years). Trochlear depth measurements had the greatest diagnostic value, with AUCs of 0.79 and 0.82 on bone and cartilage, respectively. All measurements (sulcus angle, LTI, trochlear depth) on bone and cartilage had an AUC ≥0.7 (range, 0.70-0.86), with optimal cutoff values of 145° (bone) and 154° (cartilage) for the sulcus angle, 17° (bone) and 13° (cartilage) for LTI, and 4 mm (bone) and 3 mm (cartilage) for trochlear depth. Optimal cutoff values in female patients varied from those in male patients for all measurements except for cartilaginous trochlear depth.

CONCLUSION

Normal thresholds for trochlear dysplasia varied based on the use of bony versus cartilaginous landmarks. Cartilaginous trochlear depth measurements had the greatest ability to identify knees with patellar instability. Furthermore, optimal cutoff values for all measurements except for cartilaginous trochlear depth differed between female and male patients. These findings suggest that sex-specific parameters of normal values may be needed in the assessment of risk factors for patellofemoral instability.

Rehabilitation of anterior knee pain in the pregnant athlete: Considerations and modifications by trimester

BACKGROUND

Anterior knee pain is a common symptom many females experience during pregnancy. There are several musculoskeletal changes that occur in anatomy and physiology throughout the course of pregnancy that impact the lower extremity kinetic chain. Pregnant athletes, recreational through competitive, who attempt to maintain a high activity level through each trimester may be at increased risk for anterior knee pain due to a greater demand for lumbopelvic and hip stabilization.

CLINICAL QUESTION

What are the evidence-driven rehabilitation guidelines and specific modifications needed to treat anterior knee pain in the female athlete during each trimester of pregnancy?

KEY RESULTS

We aim to provide an overview of rehabilitation treatment guidelines for pregnant females with anterior knee pain, presenting specific physiological changes and rationale for modifications, discussed by trimester. We recommend our program be conducted under the supervision of a physical therapist working closely with the athlete's obstetrics and sports medicine team.

CLINICAL APPLICATION

The number of women who are active during pregnancy is increasing. We provide an overview of the guidelines and considerations for treating women with anterior knee pain during a healthy and uneventful pregnancy.

Editorial Commentary: The Medial Patellofemoral Complex Is Composed of the Medial Patellofemoral Ligament and the Medial Quadriceps Tendon-Femoral Ligament: Do We Need to Reconstruct Both?

The medial patellofemoral ligament (MPFL) has been known as the primary soft-tissue restraint to lateral patellar translation. More recent anatomic studies have identified additional fibers that extend to the quadriceps tendon (medial quadriceps tendon-femoral ligament [MQTFL]), leading to the use of the term "medial patellofemoral complex" (MPFC) to describe the broad and variable attachment of this complex on the patella and quadriceps tendon. Whereas many techniques and outcomes of traditional MPFL reconstruction have been described, fewer reports exist on anatomic MPFC reconstruction to recreate both bundles of this complex. To date, the specific biomechanical roles of, and indications for, reconstruction of the MPFL versus MQTFL fibers have not been defined. One primary benefit of MQTFL reconstruction has been to avoid the risk of patella fracture, which is not obviated in the setting of concurrent patellar fixation when reconstructing both components of the MPFC. The risks and benefits comparing fixation on the patella, quadriceps tendon, or both with anatomic double-bundle reconstruction remain to be determined. Additional studies are needed to understand the differences between reconstructing the proximal and distal fibers of the MPFC with regard to graft length changes and femoral attachment sites, in order to optimally recreate the function of each graft bundle in the surgical treatment of patellar instability.

When the Physician Becomes the Patient: Considerations for Work, Life, and Leadership

Most orthopaedic surgeons are unprepared for serious medical illnesses. In such cases, the unique work-related and personal considerations for orthopaedic surgeons affect their career, their practice partners, and their patients. Planning together as an orthopaedic business organization for such issues can provide a framework to better navigate these difficult situations. Understanding the considerations and stressors from the individual's perspective can help provide the appropriate level of support while maintaining privacy. Throughout these considerations, open communication regarding expectations and concerns and expressions of empathy are the cornerstones of dealing with physician illness. Being a physician-patient adds complexity to an already difficult and stressful profession. Further dialogue regarding the physician-patient experience can help increase awareness of this issue and allow organizations to create a structure to best manage this almost inevitable occurrence.

Return to Play Considerations After Patellar Instability

PURPOSE OF REVIEW

To discuss the treatment options and rehabilitation protocols after non-operative and operative treatment of patellar instability, and to discuss expected return to play outcomes and functional performance with non-operative and operative treatment of patellar instability.

RECENT FINDINGS

A criterion-based program assessing range of motion, joint effusion, strength, neuromuscular control, proprioception, agility, and power are critical measures to assess when rehabilitating this population. A series of functional tests including quadriceps strength testing, single-limb hop testing, lateral step-down test, the side hop test, the lateral leap and catch test, the Y-balance test, and the depth jump should be considered when determining an athlete's return to sport clearance. These objective measures combined with psychological readiness and a comprehensive understanding of the sports-specific tasks required for participation should be considered when evaluating an athlete's ability to safely and successfully return to sport. We discuss rehabilitation management when working with non-operative and operative management of patellar instability and provide considerations for clinicians working with these athletes to facilitate safe return to sport.

What Is the Clinical Benefit of Common Orthopaedic Procedures as Assessed by the PROMIS Versus Other Validated Outcomes Tools?

BACKGROUND

Patient-reported outcome measures (PROMs), including the Patient-reported Outcomes Measurement Information System (PROMIS), are increasingly used to measure healthcare value. The minimum clinically important difference (MCID) is a metric that helps clinicians determine whether a statistically detectable improvement in a PROM after surgical care is likely to be large enough to be important to a patient or to justify an intervention that carries risk and cost. There are two major categories of MCID calculation methods, anchor-based and distribution-based. This variability, coupled with heterogeneous surgical cohorts used for existing MCID values, limits their application to clinical care.

QUESTIONS/PURPOSES

In our study, we sought (1) to determine MCID thresholds and attainment percentages for PROMIS after common orthopaedic procedures using distribution-based methods, (2) to use anchor-based MCID values from published studies as a comparison, and (3) to compare MCID attainment percentages using PROMIS scores to other validated outcomes tools such as the Hip Disability and Osteoarthritis Outcome Score (HOOS) and Knee Disability and Osteoarthritis Outcome Score (KOOS).

METHODS

This was a retrospective study at two academic medical centers and three community hospitals. The inclusion criteria for this study were patients who were age 18 years or older and who underwent elective THA for osteoarthritis, TKA for osteoarthritis, one-level posterior lumbar fusion for lumbar spinal stenosis or spondylolisthesis, anatomic total shoulder arthroplasty or reverse total shoulder arthroplasty for glenohumeral arthritis or rotator cuff arthropathy, arthroscopic anterior cruciate ligament reconstruction, arthroscopic partial meniscectomy, or arthroscopic rotator cuff repair. This yielded 14,003 patients. Patients undergoing revision operations or surgery for nondegenerative pathologies and patients without preoperative PROMs assessments were excluded, leaving 9925 patients who completed preoperative PROMIS assessments and 9478 who completed other preoperative validated outcomes tools (HOOS, KOOS, numerical rating scale for leg pain, numerical rating scale for back pain, and QuickDASH). Approximately 66% (6529 of 9925) of patients had postoperative PROMIS scores (Physical Function, Mental Health, Pain Intensity, Pain Interference, and Upper Extremity) and were included for analysis. PROMIS scores are population normalized with a mean score of 50 ± 10, with most scores falling between 30 to 70. Approximately 74% (7007 of 9478) of patients had postoperative historical assessment scores and were included for analysis. The proportion who reached the MCID was calculated for each procedure cohort at 6 months of follow-up using distribution-based MCID methods, which included a fraction of the SD (1/2 or 1/3 SD) and minimum detectable change (MDC) using statistical significance (such as the MDC 90 from p < 0.1). Previously published anchor-based MCID thresholds from similar procedure cohorts and analogous PROMs were used to calculate the proportion reaching MCID.

RESULTS

Within a given distribution-based method, MCID thresholds for PROMIS assessments were similar across multiple procedures. The MCID threshold ranged between 3.4 and 4.5 points across all procedures using the 1/2 SD method. Except for meniscectomy (3.5 points), the anchor-based PROMIS MCID thresholds (range 4.5 to 8.1 points) were higher than the SD distribution-based MCID values (2.3 to 4.5 points). The difference in MCID thresholds based on the calculation method led to a similar trend in MCID attainment. Using THA as an example, MCID attainment using PROMIS was achieved by 76% of patients using an anchor-based threshold of 7.9 points. However, 82% of THA patients attained MCID using the MDC 95 method (6.1 points), and 88% reached MCID using the 1/2 SD method (3.9 points). Using the HOOS metric (scaled from 0 to 100), 86% of THA patients reached the anchor-based MCID threshold (17.5 points). However, 91% of THA patients attained the MCID using the MDC 90 method (12.5 points), and 93% reached MCID using the 1/2 SD method (8.4 points). In general, the proportion of patients reaching MCID was lower for PROMIS than for other validated outcomes tools; for example, with the 1/2 SD method, 72% of patients who underwent arthroscopic partial meniscectomy reached the MCID on PROMIS Physical Function compared with 86% on KOOS.

CONCLUSION

MCID calculations can provide clinical correlation for PROM scores interpretation. The PROMIS form is increasingly used because of its generalizability across diagnoses. However, we found lower proportions of MCID attainment using PROMIS scores compared with historical PROMs. By using historical proportions of attainment on common orthopaedic procedures and a spectrum of MCID calculation techniques, the PROMIS MCID benchmarks are realizable for common orthopaedic procedures. For clinical practices that routinely collect PROMIS scores in the clinical setting, these results can be used by individual surgeons to evaluate personal practice trends and by healthcare systems to quantify whether clinical care initiatives result in meaningful differences. Furthermore, these MCID thresholds can be used by researchers conducting retrospective outcomes research with PROMIS.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Dynamic Ultrasound Can Accurately Quantify Severity of Medial Knee Injury: A Cadaveric Study

Purpose

To quantify the severity of medial knee injuries based on medial compartment gapping as measured by stress ultrasonography.

Methods

In 8 cadaveric knees, the distance between the medial tibial and femoral condyles was measured using ultrasonography. These measurements were obtained in the intact state and repeated after open sequential transection of the superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL), posterior oblique ligament (POL), and arthroscopic transection of the anterior cruciate ligament (ACL). Knees were evaluated at 0° and 20° of knee flexion using the Telos device under 0 N and 100 N of valgus force. Receiver operating characteristic curve analysis and the DeLong test were used to determine whether measurements could distinguish between successive severity of MCL injury after identifying the optimal cutoff value for each injury state.

Results

Of the 8 cadaveric knees included in this study, 3 were male and 5 were female. The mean age was 58 ± 11 years (range 48-82 years). When measured using ultrasonography at 20° knee flexion with valgus load, the medial tibiofemoral distance significantly increased with increasing severity of medial knee injury (P values ranging from .049 to <.001). The optimal cutoff values for distinguishing between an intact knee and sMCL injury were 8.3 mm (area under the curve [AUC] = 0.98), between sMCL and dMCL injury 9.9 mm (AUC = 0.89), dMCL and POL 16.7 mm (AUC = 0.88), and POL and ACL 18.6 mm (AUC = 0.84). When we compared combined intact and sMCL-transected stages with dMCL-transected stage, the optimal cut-off point to differentiate stable from unstable injuries was equal to 13.8 mm of medial tibiofemoral distance (AUC = 0.97; sensitivity = 100%; specificity = 94.1%).

Conclusions

Dynamic ultrasonographic assessment can accurately quantify the severity of medial knee ligament injury based on medial compartment gapping. In our study, we found medial tibiofemoral distance >13.8 mm at 20° knee flexion under valgus force indicates the presence of dMCL injury with a diagnostic accuracy of 0.97.

Clinical Relevance

Dynamic ultrasonography can quantify severity of medial knee injury without radiation and at point of care in multiple clinical settings.

Radiographic Landmarks for the Femoral Attachment of the Medial Patellofemoral Complex: A Cadaveric Study

PURPOSE

To report the radiographic landmarks for the medial patellofemoral complex (MPFC) footprint on the medial femur and describe the difference between the radiographic positions corresponding to the medial quadriceps tendon femoral ligament (MQTFL) and medial patellofemoral ligament (MPFL) fibers.

METHODS

In 8 unpaired cadaveric knees, the MPFC footprint was exposed on the medial femur, and the proximal and distal boundaries of the footprint were marked. Lateral fluoroscopic images of the knee were obtained and analyzed using Image J. The proximal boundary corresponding to the MQTFL, the MPFC midpoint, and distal boundary corresponding to the MPFL were described radiographically and compared for differences in position.

RESULTS

The proximal MQTFL footprint was 0.8 ± 0.6 mm anterior (P = .013) and 5.2 ± 1.8 mm proximal to the MPFC midpoint (P <.001), whereas the distal MPFL footprint was 0.8 ± 0.7 mm posterior (P = .012) and 5.9 ± 1.1 mm distal to the radiographic MPFC midpoint (P <.001). The radiographic point corresponding to the distal MPFL footprint was 0.8 ± 0.9 mm posterior (P = .011) and 11.1 ± 2.3 mm distal to the radiographic point of the proximal MQTFL footprint (P <.001). When using the point of intersection of the posterior cortical line and the proximal posterior condyle as a reference, 91.6% of all points correlating to the MQTFL, MPFC midpoint and MPFL, were within 10 mm in any direction from this radiographic landmark.

CONCLUSIONS

On fluoroscopic imaging, the proximal MQTFL and distal MPFL fibers had significantly different radiographic positions from the MPFC midpoint on the femur. These findings should be considered when reconstructing specific components of the MPFC.

CLINICAL RELEVANCE

As fluoroscopy is often used intraoperatively to guide graft placement, our findings may serve as a reference when differentiating the locations of the MPFL vs MQTFL on the femur for anatomic reconstruction.

Utility of Diagnostic Ultrasound in the Assessment of Patellar Instability

Background

The use of imaging to diagnose patellofemoral instability is often limited by the inability to dynamically load the joint during assessment. Therefore, the diagnosis is typically based on physical examination using the glide test to assess and quantify lateral patellar translation. However, precise quantification with this technique remains difficult.

Purpose

To quantify patellar position using ultrasound imaging under dynamic loading conditions to distinguish between knees with and without medial patellofemoral complex (MPFC) injury.

Study Design

Controlled laboratory study.

Methods

In 10 cadaveric knees, the medial patellofemoral distance was measured to quantify patellar position from 0° to 40° of knee flexion at 10° increments. Knees were evaluated at each flexion angle under unloaded conditions and with 20 N of laterally directed force on the patella to mimic the glide test. Patellar position measurements were made on ultrasound images obtained before and after MPFC transection and compared for significant differences. To determine the ability of medial patellofemoral measurements to differentiate between MPFC-intact and MPFC-deficient states, area under the receiver operating characteristic (ROC) curve analysis and the Delong test were used. The optimal cutoff value to distinguish between the deficient and intact states was determined using the Youden J statistic.

Results

A significant increase in medial patellofemoral distance was observed in the MPFC-deficient state as compared with the intact state at all flexion angles (P = .005 to P < .001). When compared with the intact state, MPFC deficiency increased medial patellofemoral distance by 32.8% (6 mm) at 20° of knee flexion under 20-N load. Based on ROC analysis and the J statistic, the optimal threshold for identifying MPFC injury was 19.2 mm of medial patellofemoral distance at 20° of flexion under dynamic loading conditions (area under the ROC curve = 0.93, sensitivity = 77.8%, specificity = 100%, accuracy = 88.9%).

Conclusion

Using dynamic ultrasound assessment, we found that medial patellofemoral distance significantly increases with disruption of the MPFC.

Clinical Relevance

Dynamic ultrasound measurements can be used to accurately detect the presence of complete MPFC injury.

Editorial Commentary: Handling the (Contact) Pressure in Patellofemoral Surgery: The Role of Lateral Retinacular Release

The role of lateral retinacular release for the treatment of patellofemoral pathology has evolved over the years. Although once popularized in the treatment of patellofemoral pain and instability, complications such as iatrogenic medial patellar instability and decreases in lateral patellar stability have limited the indications for performing isolated lateral release. However, there exists a need for more clearly defined parameters and understanding of when and how lateral release should be incorporated with other procedures during patellar stabilization and joint-preservation surgery. Advances in finite element analysis, as well as refining our surgical indications and techniques for concurrent lateral release, will allow us to optimize both joint pressures and stability during the surgical management of patellar instability.

Arthroscopic Patellofemoral Measurements Can Reliably Assess Patellar Instability

PURPOSE

To arthroscopically describe patellar position based on lateralization, tilt, and engagement, and compare measurements in normal, medial patellofemoral complex-(MPFC) deficient, and MPFC-reconstructed knees.

METHODS

In 10 cadaveric knees, arthroscopic patellar position was assessed by performing digital measurements on arthroscopic images obtained through a standard anterolateral portal. Lateralization was measured as millimeters overhang of the patella past the lateral edge of the lateral femoral condyle, viewing from the lateral gutter. Patellar tilt was calculated as the difference in medial and lateral distances from the patella to the trochlea, viewing from the sunrise view. Patellotrochlear distance was measured as the anteroposterior distance between the central trochlear groove and patella on the sunrise view. Measurements were obtained at 10° intervals of knee flexion from 0° to 90°, in intact knees (group 1), after arthroscopically transecting the MPFC fibers (group 2), and after MPFC reconstruction (group 3). Optimal cutoff values were identified to distinguish between intact versus MPFC-deficient states.

RESULTS

When compared to group 1, group 2 demonstrated increased patellar lateralization by 22.5% at 0°-40° knee flexion (P = .006), which corrected to baseline in group 3 (P = .006). Patellar tilt measurements demonstrated no differences between groups. Patellotrochlear distance increased by 21.0% after MPFC transection (P = .031) at 0°-40° knee flexion, with correction to baseline after MPFC reconstruction (P = .031). More than 7 mm of lateral overhang at 20°-30° flexion and >6 mm of patellotrochlear distance at 10°-20° flexion were found to indicate MPFC deficiency.

CONCLUSIONS

Utilizing standardized arthroscopic views, we identified significant increases in patellar lateralization and patellotrochlear distance in early knee flexion angles after MPFC transection, and these changes normalized after MPFC reconstruction.

CLINICAL RELEVANCE

Arthroscopic assessments of patellar position may be useful in evaluating patellofemoral stability during patellar stabilization surgery.

Characterization of knee dysfunction and related risk factors during pregnancy

BACKGROUND

Knee pain can be a common complaint during pregnancy; however, the severity of symptoms and their associated risk factors have not been described.

QUESTIONS/PURPOSES

The aim of this study was to characterize knee-related dysfunction and describe risk factors in a general obstetric population.

PATIENTS AND METHODS

Patients in obstetric clinics completed the International Knee Documentation Committee (IKDC) questionnaire to assess their knee function, as well as the Pregnancy Physical Activity Questionnaire (PPAQ), a validated tool to assess physical activity. Age, weeks gestation, height, weight, and history of knee problems prior to pregnancy were analyzed to identify independent associations with IKDC score and determine predictors of knee dysfunction.

RESULTS

310 patients were included in this study, of which 68, 111 and 131 were in their first, second and trimesters, respectively. Mean age of the total study group was 30.3 ± 5.5 years. Knee function decreased with each trimester, from a mean IKDC score of 88.9 ± 13.0 in the first trimester, 84.5 ± 16.8 in the second, and 82.0 ± 20.0 in the third, with corresponding decreases in activity levels of 258.5 ± 141.7, 254.0 ± 141.5, and 246.1 ± 156.6 MET-h/wk. Of the total study group, 26.1% had IKDC scores <75, including 13.2%, 25.2%, and 33.6% in the first, second and third trimesters. Risk factors for knee dysfunction included high activity levels of PPAQ ≥ 500 MET-h/wk (OR 2.8), history of knee problems (OR 2.7), age <25 years (OR 2.6), and BMI ≥ 30 kg/m² (OR 1.9).

CONCLUSION

In our cohort, 26.1% of pregnant women reported severe knee dysfunction, and this was associated with high levels of activity, younger age, greater BMI, and history of knee problems. These findings may have implications for women who wish to maintain training and fitness during pregnancy. Future studies are recommended to assess the need for intervention, as well as to identify optimal methods to prevent and address symptoms in this population.

LEVEL OF EVIDENCE

IV, Case Series.

Rehabilitation and Return to Sport After Medial Patellofemoral Complex Reconstruction

The medial patellofemoral complex (MPFC) consists of the medial patellofemoral ligament and medial quadriceps tendon femoral ligament, which play a critical role stabilizing the patella against lateral translation. After a patellar dislocation, athletes with recurrent dislocations have functional limitations that may limit their return to their prior level of competition, requiring surgical reconstruction. Although ample literature exists delineating return-to-play (RTP) considerations after anterior cruciate ligament reconstruction, there is a paucity of evidence specific to MPFC reconstruction. Athletes aiming to return to sport after MPFC reconstruction require the same methodical treatment approach to ensure safe RTP. A criterion-based periodical assessment of progress that measures range of motion, strength, neuromuscular control, balance, agility, and power are pivotal components of rehabilitating this population. A combination of objective and subjective criteria should be assessed when determining an individual’s readiness for sports-specific activities. A battery of functional tests, including quadriceps strength testing, single-limb hop testing, lateral step-down test, the lateral leap and catch test, the Y-balance test, and the depth jump should be considered when evaluating the athlete for readiness for sport, incorporating specific understanding of the biomechanics of the patellofemoral joint. We discuss the considerations for return-to-sport rehabilitation and testing after MPFC reconstruction, to provide clinicians working with an athletic population a framework to adequately prepare their athletes for safe return to sport.

Changes in U.S. girls' participation in high school sports: implications for injury awareness

CONTEXT

The number of female athletes has grown exponentially since Title IX. However, little data exists on the proportion of women and girls who play each sport.

OBJECTIVE

To quantify changes in female sports participation in high school sports from 1973 to 2018.

DESIGN

Retrospective analysis of data from the National Federation of State High School Associations Participation Survey.

SETTING

US high schools.

PARTICIPANTS

US high school athletes from 1973 to 2018.

MAIN OUTCOME MEASURES

Percentage of female participation for each high school sport in 5-year intervals; and changes in rates of participation by player gender and sport at designated intervals.

RESULTS

From 1973 to 2018, the percentage of high school sports played by girls increased from 24.2% to 42.9% ([95%CI, 18.6,18.8], p < 0.0001). In the 14 sports included in our study, all had an increase in the percentage of female participation between 1973 and 2018. >80% of the increases occurred between 1973 and 1998 for all sports except lacrosse, ice hockey, football, and wrestling. Between 1998 and 2018, the percentage of girls playing each sport increased by less than 5% in all sports, except for ice hockey (11.5%, 95% CI 11.0, 12.0, p < 0.001) and wrestling (7.1%, 95% CI 6.9, 7.1, p < 0.001).

CONCLUSIONS

Girls' participation in high school sports continues to grow not only in numbers but in the types of sports played. Between 1998 and 2018, the greatest increases were noted in ice hockey and wrestling, which had fewer than 1% female participation before 1998. Physicians providing care for female athletes should be aware of these changes and understand the potential injuries associated with these sports.

Factors Influencing Graft Function following MPFL Reconstruction: A Dynamic Simulation Study

Medial patellofemoral ligament (MPFL) reconstruction is currently the primary surgical procedure for treating recurrent lateral patellar instability. The understanding of graft function has largely been based on studies performed with normal knees. The current study was performed to characterize graft function following MPFL reconstruction, focusing on the influence of pathologic anatomy on graft tension, variations with knee flexion, and the influence on patellar tracking. Knee squatting was simulated with 15 multibody dynamic simulation models representing knees being treated for recurrent lateral patellar instability. Squatting was simulated in a preoperative condition and following MPFL reconstruction with a hamstrings tendon graft set to allow 0.5 quadrants of lateral patellar translation with the knee at 30 degrees of flexion. Linear regressions were performed to relate maximum tension in the graft to parameters of knee anatomy. Repeated measures comparisons evaluated variations in patellar tracking at 5-degree increments of knee flexion. Maximum graft tension was significantly correlated with a parameter characterizing lateral position of the tibial tuberosity (maximum lateral tibial tuberosity to posterior cruciate ligament attachment distance, r ² = 0.73, p < 0.001). No significant correlations were identified for parameters related to trochlear dysplasia (lateral trochlear inclination) or patella alta (Caton-Deschamps index and patellotrochlear index). Graft tension peaked at low flexion angles and was minimal by 30 degrees of flexion. MPFL reconstruction decreased lateral patellar shift (bisect offset index) compared with preoperative tracking at all flexion angles from 0 to 50 degrees of flexion, except 45 degrees. At 0 degrees, the average bisect offset index decreased from 0.81 for the preoperative condition to 0.71. The results indicate that tension within an MPFL graft increases with the lateral position of the tibial tuberosity. The graft tension peaks at low flexion angles and decreases lateral patellar maltracking. The factors that influence graft function following MPFL reconstruction need to be understood to limit patellar maltracking without overloading the graft or over constraining the patella.

Influence of tibial tuberosity position and trochlear depth on patellar tracking in patellar instability: Variations with Patella Alta

BACKGROUND

Patella alta reduces articular constraints acting on the patella from the trochlear groove with the knee extended. The current study was performed to address how patella alta alters the influence of tibial tuberosity position and trochlear depth on patellar tracking in patients being treated for patellar instability.

METHODS

Fifteen subjects with recurrent patellar instability participated in knee extension within a dynamic CT scanner. Computational models were reconstructed from the motions to characterize patellar lateral shift, patellar tilt, patellar height, trochlear depth and lateral position of the tibial tuberosity at 0° and 30° of knee flexion. Linear regressions were used to correlate patellar tracking with anatomy for an alta group (7 knees, Caton-Deschamps index > 1.2) and a non-alta group.

FINDINGS

For the alta group, lateral patellar shift and tilt increased with increasing lateral position of the tibial tuberosity at 0° (r² > 0.8, P < 0.005). For the non-alta group, lateral patellar shift and tilt increased as depth of the groove decreased at 0° (r² > 0.8, P = 0.001). Lateral patellar tilt also increased with increasing lateral position of the tibial tuberosity at 30° for the non-alta group (r² = 0.55, P = 0.04).

INTERPRETATION

For patients with patellar instability, lateral patellar maltracking with the knee extended can be largely attributed to either a shallow trochlear groove or a combination of patella alta and a lateral position of the tibial tuberosity. These relationships should be considered in both conservative and surgical treatment planning.

Current Concepts Regarding Patellofemoral Trochlear Dysplasia

Optimal treatment of patients with patellofemoral trochlear dysplasia and recurrent patellar instability requires in-depth understanding of this complex structural anomaly. An extensive review of the literature suggests that dysplasia occurs as a result of aberrant forces applied to the patellofemoral joint in the majority of cases. Evidence supports surgical stabilization that reconstructs the medial patellofemoral and/or medial quadriceps tendon-femoral ligament without added trochleoplasty in the majority of patients with trochlear dysplasia and recurrent patellar instability. Adding tibial tubercle transfer distally, medially, or anteromedially in those who need it to treat specific deficits in alignment or articular cartilage can be beneficial in selected patients with trochlear dysplasia and recurrent patellar instability. Trochleoplasty may be appropriate in those few cases in which permanent stable patellofemoral tracking cannot be restored otherwise, but the indications are not yet clear, particularly as trochleoplasty adds risk to the articular cartilage. Improved understanding of imaging techniques and 3-dimensional reproductions of dysplastic patellofemoral joints are useful in surgical planning for patients with recurrent patellar instability and trochlear dysplasia.

Editorial Commentary: Trochlear Dysplasia Is Difficult to Measure, No Matter How You Slice It

Trochlear dysplasia is one of the primary morphologic abnormalities associated with patellar instability. Although qualitative classifications based on trochlear shape such as the Dejour classification exist, radiographic measurements to quantify the severity of trochlear dysplasia are numerous and varied. Each measurement addresses a different element of the complex and wide-ranging presentations that exist along a spectrum of abnormalities in trochlear morphology, and the reported reliability of such measurements are mixed. Overall, our understanding of trochlear dysplasia continues to evolve, and the ability to quantify the morphology of the trochlea, as well as its influence on patellar stability, remains a work in progress. Future directions include developing improved 3-dimensional descriptions of trochlear anatomy, as well as standardizing measurement methods and image slice selection, to better evaluate trochlear morphology in the assessment of patellar instability.

Femoral Origin Anatomy of the Medial Patellofemoral Complex: Implications for Reconstruction

PURPOSE

To report the shape and orientation of the medial patellofemoral complex (MPFC) footprint on the medial femur and describe the difference between the proximal (medial quadriceps tendon femoral ligament, MQTFL) and distal (medial patellofemoral ligament, MPFL) fibers.

METHODS

In 20 cadaveric knees, the MPFC footprint on the medial femur was exposed. Images of the medial femur were analyzed using ImageJ software. The length and width of the MPFC footprint were described to the nearest 0.1 mm; the angle of its long axis was described relative to the axis of the femoral shaft (0.1°). The footprint's most proximal and distal margins were described in relation to the adductor tubercle and medial epicondyle. The differences between each were compared using paired t tests.

RESULTS

17 knees from 10 cadavers were included in this study. The MPFC footprint had a length of 11.7 ± 1.8 mm and a width of 1.7 ± 0.4 mm. The long axis of the footprint was at an angle 14.6° ± 16.6° anterior to the axis of the femoral shaft. The most proximal (MQTFL) fibers originated 7.4 ± 3.8 mm anterior and 1.8 ± 4.7 mm distal to the adductor tubercle and 4.1 ± 2.9 mm posterior and 8.4 ± 5.6 mm proximal to the medial epicondyle. The most distal (MPFL) fibers originated 4.9 ± 4.2 mm anterior and 12.7 ± 4.3 mm distal to the adductor tubercle, as well as 7.1 ± 2.4 mm posterior and 0.5 ± 5.6 mm distal to the medial epicondyle. The distal margin of the femoral MPFC footprint was 10.9 ± 1.7 mm distal (p < .001) and 2.6 ± 3.2 mm more posterior (p = .005) than the proximal margin.

CONCLUSIONS

The femoral footprint of the MPFC has a length almost 7 times greater than its width, with the distal margin being 10.9 mm distal and 2.6 mm posterior to the proximal margin.

CLINICAL RELEVANCE

This differential anatomy within the femoral origin suggests that MPFL and MQTFL reconstruction may require separate positions of femoral fixation to recreate the anatomy of these fibers.

Evidence-based Risk Stratification for Sport Medicine Procedures During the COVID-19 Pandemic

Orthopaedic practices have been markedly affected by the emergence of the COVID-19 pandemic. Despite the ban on elective procedures, it is impossible to define the medical urgency of a case solely on whether a case is on an elective surgery schedule. Orthopaedic surgical procedures should consider COVID-19-associated risks and an assimilation of all available disease dependent, disease independent, and logistical information that is tailored to each patient, institution, and region. Using an evidence-based risk stratification of clinical urgency, we provide a framework for prioritization of orthopaedic sport medicine procedures that encompasses such factors. This can be used to facilitate the risk-benefit assessment of the timing and setting of a procedure during the COVID-19 pandemic.

Telemedicine in the Era of COVID-19: The Virtual Orthopaedic Examination

With the onset of the COVID-19 pandemic, the shifting of clinical care to telemedicine visits has been hastened. Because of current limitations in resources, many elective surgeons have been forced to venture into utilizing telemedicine, in which the standards for orthopaedic examinations have not previously been fully developed. We report our experience with protocols and methods to standardize these visits to maximize the benefit and efficiency of the virtual orthopaedic examination. At the time of scheduling, patients are asked to prepare for their virtual visit and are given a checklist. In addition to confirming audiovisual capabilities prior to the visit, patients are given specific instructions on camera positioning, body positioning, setting, and attire to improve the efficiency of the visit. During the examination, digital tools can be utilized as needed. In the setting of outpatient injury evaluations, a systematic virtual examination can aid in triaging and managing common musculoskeletal conditions. With the rapid incorporation of telehealth visits, as well as the unknown future with regard to the pandemic, the utilization and capabilities of telemedicine will continue to expand. Future directions include the development of validated, modified examination techniques and new technology that will allow for improved interactive physical examinations, as we rapidly move forward into the realm of telemedicine due to unexpected necessity.

Editorial Commentary: Repair or Reconstruct? Addressing Medial Patellofemoral Ligament Insufficiency in the Absence of Morphologic Abnormalities

The role of medial patellofemoral ligament (MPFL) repair versus reconstruction in the treatment of patellar instability continues to undergo debate. Repair of the ligament can be technically less demanding with fewer risks of morbidity, whereas reconstruction carries concerns of graft malpositioning or over-tensioning as well as the risk of patellar fracture. Studies directly comparing the 2 procedures in the setting of recurrent patellar instability have consisted of small series or low levels of evidence that inevitably include patients with concurrent morphologic risk factors such as tuberosity malalignment or patella alta, which are known factors that can influence the biomechanical behavior of the MPFL. Heterogeneity in patient-related risk factors and surgical techniques continues to pose limitations in allowing for direct comparisons between procedures. For the treatment of recurrent patellar instability in the setting of no (or concurrently addressed) morphologic abnormalities, MPFL reconstruction has become a common procedure and generally preferred approach. The superior outcomes associated with reconstruction over repair, however, should be qualified with the fact that attention to the critical details of the technique, including graft position and tension, is paramount to success when performing this procedure.

Telemedicine in the Era of COVID-19: The Virtual Orthopaedic Examination

With the onset of the COVID-19 pandemic, the shifting of clinical care to telemedicine visits has been hastened. Because of current limitations in resources, many elective surgeons have been forced to venture into utilizing telemedicine, in which the standards for orthopaedic examinations have not previously been fully developed. We report our experience with protocols and methods to standardize these visits to maximize the benefit and efficiency of the virtual orthopaedic examination. At the time of scheduling, patients are asked to prepare for their virtual visit and are given a checklist. In addition to confirming audiovisual capabilities prior to the visit, patients are given specific instructions on camera positioning, body positioning, setting, and attire to improve the efficiency of the visit. During the examination, digital tools can be utilized as needed. In the setting of outpatient injury evaluations, a systematic virtual examination can aid in triaging and managing common musculoskeletal conditions. With the rapid incorporation of telehealth visits, as well as the unknown future with regard to the pandemic, the utilization and capabilities of telemedicine will continue to expand. Future directions include the development of validated, modified examination techniques and new technology that will allow for improved interactive physical examinations, as we rapidly move forward into the realm of telemedicine due to unexpected necessity.

Tibial tuberosity anteriomedialization vs. medial patellofemoral ligament reconstruction for treatment of patellar instability related to malalignment: Computational simulation

BACKGROUND

Medial patellofemoral ligament reconstruction and tibial tuberosity anteromedialization are common treatment options for recurrent lateral patellar instability, although ligament reconstruction is not commonly applied to knees with lateral malalignment.

METHODS

Multibody dynamic simulation was used to assess knee function following tibial tuberosity anteromedialization and medial patellofemoral ligament reconstruction for knees with lateral malalignment. Dual limb squatting was simulated with six models representing knees being treated for patellar instability with an elevated tibial tuberosity to trochlear groove distance. The patellar tendon attachment on the tibia was shifted medially (10 mm) and anteriorly (5 mm) to represent tibial tuberosity anteromedialization. A hamstrings tendon graft was represented for medial patellofemoral ligament reconstruction. Patellar tracking was quantified based on bisect offset index. The patellofemoral contact pressure distribution was quantified using discrete element analysis. Data were analyzed with repeated measures comparisons with post-hoc tests.

FINDINGS

Both procedures significantly reduced bisect offset index, primarily at low flexion angles. The decrease was larger for tibial tuberosity anteromedialization, peaking at 0.18. Tibial tuberosity anteromedialization shifted contact pressures medially, significantly increasing the maximum medial contact pressure at multiple flexion angles, with the maximum pressure increasing up to 1 MPa.

INTERPRETATION

The results indicate tibial tuberosity anteromedialization decreases lateral patellar maltracking more effectively than medial patellofemoral ligament reconstruction, but shifts contact pressure medially. Tibial tuberosity anteromedialization is likely to reduce the risk of post-operative instability compared to medial patellofemoral ligament reconstruction. The medial shift in the pressure distribution should be considered for knees with medial cartilage lesions, however.

Awareness of Anterior Cruciate Ligament Injury-Preventive Training Programs Among Female Collegiate Athletes

CONTEXT

Neuromuscular training programs can reduce the rate of noncontact anterior cruciate ligament (ACL) injuries, particularly in female athletes.

OBJECTIVE

To assess the awareness of, experience with, and factors associated with participation in preventive training programs (PTPs) among female collegiate athletes and their knowledge of ACL injuries.

DESIGN

Cross-sectional study.

SETTING

National Collegiate Athletic Association (NCAA) sports programs.

PATIENTS OR OTHER PARTICIPANTS

A total of 440 female NCAA athletes (age = 20 ± 1 years) representing 20 sports during the 2017-2018 academic year.

MAIN OUTCOME MEASURE(S)

We used a 12-item survey to collect data on each participant's age, sport, position, college, NCAA division, and awareness of and experience with PTPs. We performed descriptive statistics and used odds ratios (ORs) to assess relationships between demographic data and awareness of or interest in PTPs.

RESULTS

Of the 440 respondents, 85% (n = 373) knew that female athletes were at higher risk for sustaining ACL injuries than male athletes, and 89% (n = 391) knew that ACL injuries were preventable. Thirty-three percent (n = 143) were familiar with the concept of ACL PTPs. Only 15% (n = 64) had ever performed PTPs, but 89% (n = 391) reported they would perform a daily PTP if it could prevent ACL injuries. Fifty-two of the 64 respondents (81%) who had performed PTPs said athletic trainers or coaches oversaw the PTPs. Participants were more likely to be familiar with ACL PTPs if they (OR = 3.5; 95% confidence interval [CI] = 2.0, 5.8) or a teammate (OR = 4.6; 95% CI = 2.1, 9.8) had sustained an ACL injury. Respondents were more willing to perform PTPs if they (OR = 2.3; 95% CI = 0.80, 6.6) or a teammate (OR = 3.4; 95% CI = 1.8, 6.6) had sustained an ACL injury.

CONCLUSIONS

Although 89% of respondents expressed interest in performing daily ACL PTPs, only 15% had performed such programs, and only 33% were familiar with the concept of ACL PTPs.

Accuracy and Reliability of the Visual Assessment of Patellar Tracking

BACKGROUND

Abnormal patellar tracking is described as a "J-sign" when the patella exhibits excessive lateral displacement during active knee extension.

PURPOSE

To determine (1) the accuracy and reliability of the visual assessment of patellar tracking when viewed by surgeons with patellofemoral expertise and (2) whether surgeon experience (in years) correlates with the ability to accurately identify the presence and severity of patellar maltracking.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Using a web-based assessment, 32 orthopaedic surgeon members of the International Patellofemoral Study Group determined the presence or absence of maltracking (≥2 quadrants of lateral translation) in 10 single-knee videos of patients with patellar instability during active knee extension (qualitative analysis). Surgeons then graded patellar tracking in 20 single-knee videos as follows: 0 (<1 patellar quadrant of lateral translation), 1 (1 to <2 quadrants), 2 (2 to <3 quadrants), or 3 (≥3 quadrants) (quantitative analysis). Responses were compared with a previously described grading system using patellar bisect offset measured with 4-dimensional computed tomography. We evaluated the association between number of years of surgeon experience and the ability to correctly identify and grade patellar tracking. A total of 22 surgeons repeated the survey 3 months later, and their answers were matched to the first survey, allowing for assessment of intraobserver reliability.

RESULTS

In the qualitative analysis, surgeons correctly identified videos as showing patellar maltracking 68% of the time (κ = 0.45). In the quantitative analysis, 53%, 51%, 48%, and 68% of surgeons correctly identified maltracking of grades 3, 2, 1, and 0, respectively (κ = 0.42). Surgeon experience did not correlate with ability to identify the presence (P = .59) or grade (P = .35) of patellar maltracking. Respondent answers from the second survey demonstrated inadequate intraobserver reliability (κ = 0.48).

CONCLUSION

Using visual assessment alone, surgeons correctly identified patellar maltracking in approximately two-thirds of videos and correctly graded patellar maltracking in half. Inter- and intraobserver reliability were inadequate to support the use of visual assessment alone for detecting the presence or grade of patellar maltracking. Surgeon experience did not correlate with ability to identify the presence or grade of patellar maltracking.

Correction to: Recognition of evolving medial patellofemoral anatomy provides insight for reconstruction

Unfortunately, the middle name of author was incorrectly published as Jorge A. Chahla instead of Jorge Chahla in the original article.

Atlas-based algorithm for automatic anatomical measurements in the knee

We present an algorithm for automatic anatomical measurements in tomographic datasets of the knee. The algorithm uses a set of atlases, each consisting of a knee image, surface segmentations of the bones, and locations of landmarks required by the anatomical metrics. A multistage volume-to-volume and surface-to-volume registration is performed to transfer the landmarks from the atlases to the target volume. Manual segmentation of the target volume is not required in this approach. Metrics were computed from the transferred landmarks of a best-matching atlas member (different for each bone), identified based on a mutual information criterion. Leave-one-out validation of the algorithm was performed on 24 scans of the knee obtained using extremity cone-beam computed tomography. Intraclass correlation (ICC) between the algorithm and the expert who generated atlas landmarks was above 0.95 for all metrics. This compares favorably to inter-reader ICC, which varied from 0.19 to 0.95, depending on the metric. Absolute agreement with the expert was also good, with median errors below 0.25 deg for measurements of tibial slope and static alignment, and below 0.2 mm for tibial tuberosity-trochlear groove distance and medial tibial depth. The automatic approach is anticipated to improve measurement workflow and mitigate the effects of operator experience and training on reliability of the metrics.

Pregnancy-Related Ligamentous Laxity Mimicking Dynamic Scapholunate Instability: A Case Report

CASE

A 29-year-old woman presented with spontaneous, isolated, total palmar scaphoid subluxation in the left hand approximately 6 weeks postpartum. She had a positive Watson scaphoid shift test, with an easily subluxable and reducible scaphoid unilaterally. She was diagnosed with scapholunate ligamentous laxity with dynamic instability. Approximately 4 months after stopping lactation, she had complete resolution of the scapholunate subluxation; there was no recurrence of symptoms over the next 5 years of follow-up.

CONCLUSION

Women can have manifestations of pregnancy and lactation-related ligamentous laxity, including scapholunate instability, which may spontaneously resolve upon cessation of lactation.

Epidemiology of Recurrent Anterior Cruciate Ligament Injuries in National Collegiate Athletic Association Sports: The Injury Surveillance Program, 2004-2014

Background:

An anterior cruciate ligament (ACL) rupture is a serious injury that can be career-ending in collegiate athletics. A rerupture after primary ACL reconstruction occurs in 1% to 11% of all athletes.

Purpose:

To describe the epidemiology of recurrent ACL ruptures in the 25 National Collegiate Athletic Association (NCAA) sports in the NCAA Injury Surveillance Program (ISP) and to identify and compare sport-specific risk factors for a recurrent ACL rupture.

Study Design:

Descriptive epidemiology study.

Methods:

Athletes who experienced a primary or recurrent ACL rupture between 2004 and 2014 were identified using data from the NCAA ISP. ACL ruptures occurred in 12 of 25 sports during the study period. We assessed the rates and patterns of primary and recurrent ACL ruptures and reported them as events per 10,000 athlete-exposures (AEs). Sex-comparable sports were compared using rate ratios. Rupture rates were compared using odds ratios, with P values <.05 indicating significance. Regular-season and postseason data were combined because of low counts of postseason events.

Results:

Of 350,416 AEs, there were 1105 ACL ruptures, 126 of which were recurrent. The highest rates of recurrent ACL ruptures (per 10,000 AEs) were among male football players (15), female gymnasts (8.2), and female soccer players (5.2). Of sports played by athletes of both sexes, women’s soccer had a significantly higher rate of recurrent ACL ruptures than men’s soccer (rate ratio, 3.8 [95% CI, 1.3-15]). Among all sports, men had a significantly higher rate of recurrent ACL ruptures (4.3) than women (3.0) (P = .04). Overall, the ratio of recurrent to primary ACL ruptures decreased over the 10-year study period. Both women and men had a decreasing trend of recurrent to primary ACL ruptures, although women had a steeper decrease.

Conclusion:

These data can help identify athletes who are most at risk of recurrent ACL ruptures after ACL reconstruction and who may benefit from injury prevention programs.

The medial patellofemoral complex

PURPOSE OF REVIEW

The purpose of this review is to describe the current understanding of the medial patellofemoral complex, including recent anatomic advances, evaluation of indications for reconstruction with concomitant pathology, and surgical reconstruction techniques.

RECENT FINDINGS

Recent advances in our understanding of MPFC anatomy have found that there are fibers that insert onto the deep quadriceps tendon as well as the patella, thus earning the name "medial patellofemoral complex" to allow for the variability in its anatomy. In MPFC reconstruction, anatomic origin and insertion points and appropriate graft length are critical to prevent overconstraint of the patellofemoral joint. The MPFC is a crucial soft tissue checkrein to lateral patellar translation, and its repair or reconstruction results in good restoration of patellofemoral stability. As our understanding of MPFC anatomy evolves, further studies are needed to apply its relevance in kinematics and surgical applications to its role in maintaining patellar stability.

Measuring Malalignment on Imaging in the Treatment of Patellofemoral Instability

Assessment of malalignment is an important factor in determining surgical treatment options for patellar instability. Measurement of tibial tubercle-trochlear groove (TT-TG) distance is valuable in planning surgical treatment for patellar instability, because it quantifies a component of malalignment and aids in deciding whether to perform tibial tuberosity osteotomy. In this paper we review how TT-TG distance should be understood in the context of many measurement factors to allow for an individualized procedure that addresses the specific contributors to patellar instability in each patient. Understanding the limitations of and variability in radiographic assessments of TT and TG positions can help in deciding whether to perform TT osteotomy for patellar instability.