Association of Tibial Tubercle-Trochlear Groove Distance With Risk of ACL Graft Failure.

Background: Limited evidence suggests a positive correlation between tibial tubercle-trochlear groove (TT-TG) distance and the risk of native anterior cruciate ligament (ACL) tear. The relationship between TT-TG distance and the risk of ACL graft failure is unknown. Hypothesis: TT-TG distance is independently associated with risk of ACL graft failure. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent ACL revision surgery between 2010 and 2018 at a single institution were identified. A control cohort underwent primary ACL reconstruction (ACLR) between 2006 and 2015, with no evidence of graft failure at 8.1 ± 2.5 years postoperatively. Record review included anthropometrics, graft type, and estimated Tegner activity score at ≥6 months after primary ACLR. Magnetic resonance imaging (MRI) scans after native ACL tear (controls) or graft failure (revision cohort) were assessed for (1) TT-TG distance, (2) proximal tibial slopes, (3) depth of tibial plateau concavity, and (4) tunnel position (revision cohort). Associations between ACL graft failure and MRI measurements, surgical variables, and patient characteristics were evaluated with logistic regression analyses. Sensitivity analyses, excluding patients with tunnel malposition, were performed to confirm multivariable results in patients with "ideal" tunnel placement. Results: Participants included 153 patients who underwent revisions and 144 controls. Controls were older than the patients who underwent revision (26.6 ± 8.8 vs 20.6 ± 7.3 years; P < .001). The mean TT-TG distance and lateral posterior tibial slope (PTS) were smaller for the control group than for the revision group (TT-TG: 9.3 ± 3.9 vs 11.2 ± 4.2 mm; P < .001; lateral PTS: 6.2° ± 3.3° vs 7.2° ± 3.6°; P = .01). TT-TG distance, lateral PTS, and age were associated with risk of ACL graft failure by multivariable analysis (OR, 1.15; 95% CI, 1.07-1.23; P < .001; OR, 1.13; 95% CI, 1.04-1.22; P = .004; and OR, 0.90; 95% CI, 0.87-0.94; P < .001, respectively). With sensitivity analyses, TT-TG distance, lateral PTS, and age at index surgery remained significantly and independently associated with ACL graft failure. Conclusion: Increased TT-TG distance, increased lateral PTS, and younger age are independently associated with increased odds of ACL graft failure. Patients with these characteristics may require a more comprehensive strategy to reduce the risk of ACL reinjury.

Quadriceps Performance and Running Biomechanics Influence Femur BMD Changes after ACL Reconstruction in Collegiate Athletes.

PURPOSE: Reduced bone mineral density of the distal femur (BMD DF ) can persist long term after anterior cruciate ligament reconstruction (ACLR), even in athletes who return to high levels of competition. These deficits may have implications for the onset and progression of knee osteoarthritis. It is unknown if clinically modifiable factors are associated with losses in BMD DF . This study evaluated the potential influence of knee extensor peak torque (PT), rate of torque development (RTD), as well as peak knee flexion (PKF) angle and peak knee extensor moment (PKEM) during running, on longitudinal changes in BMD DF post-ACLR. METHODS: After ACLR, 57 Division I collegiate athletes underwent serial whole-body dual-energy x-ray absorptiometry (DXA) scans between 3 and 24 months post-ACLR. Of these, 43 athletes also had isometric knee extensor testing (21 female, 105 observations), and 54 had running analyses (26 female, 141 observations). Linear mixed-effects models, controlling for sex, assessed the influence of surgical limb quadriceps performance (PT and RTD), running mechanics (PKF and PKEM), and time post-ACLR on BMD DF (5% and 15% of femur length). Simple slope analyses were used to explore interactions. RESULTS: Athletes with RTD less than 7.20 (N·m)·kg -1 ·s -1 (mean) at 9.3 months post-ACLR demonstrated significant decreases in 15% BMD DF over time ( P = 0.03). Athletes with PKEM during running less than 0.92 (N·m)·kg -1 (-1 SD below mean) at 9.8 months post-ACLR demonstrated significant decreases in 15% BMD DF over time ( P = 0.02). Significant slopes were not detected at -1 SD below the mean for PT (1.75 (N·m)·kg -1 , P = 0.07) and PKF (31.3°, P = 0.08). CONCLUSIONS: Worse quadriceps RTD and running PKEM were associated with a greater loss of BMD DF between 3 and 24 months post-ACLR.

Adolescent Bone Advantages 3 Years After Resistance Training Trial.

PURPOSE: We assessed maintenance of skeletal advantages 3 years after completion of a 2-year, school-based, controlled exercise trial in adolescent girls. METHOD: Middle-school girls participated in a resistance training program embedded in physical education classes. Effort groups (low-effort group [LO] and high-effort group [HI]) were identified; the control group (CON) participated in standard physical education at a separate school. Baseline and follow-up (FU) assessments at 6, 18, and 54 (FU3) months included densitometry, anthropometry, and questionnaires assessing physical maturity and nonintervention organized physical activity. Linear mixed effects models were fit to evaluate bone outcomes across all FU time points for CON versus LO/HI. RESULTS: Sixty-eight girls (23 CON/25 HI/20 LO) were 11.6 (0.3) years at baseline. Bone parameters did not differ at baseline, except femoral neck bone mineral density (LO < HI/CON, P < .05). Forty-seven participants provided FU3 assessment: 17 CON/16 HI/14 LO. After adjusting for height, gynecologic age, baseline bone, and organized physical activity, bone gains across all time points were greater for HI versus CON for legs bone mineral content, femoral neck bone mineral content/bone mineral density, and third lumbar vertebra bone mineral content/bone mineral density (P ≤ .05). At FU3, bone values were greater for HI versus CON at subhead, legs, femoral neck, and third lumbar vertebra (P < .03). CONCLUSION: Adolescent girls who exerted high effort in a school-based resistance training program demonstrated significant skeletal benefits 3 years after program completion.

Changes in Bone Mineral Density of the Femur and Tibia Before Injury to 2 Years After Anterior Cruciate Ligament Reconstruction in Division I Collegiate Athletes.

BACKGROUND: Osteoarthritis (OA) is a significant long term concern after anterior cruciate ligament (ACL) reconstruction (ACLR). A low bone mineral density (BMD), particularly in the subchondral region, has been associated with the development of OA and is evident at the knee in patients long after ACLR. It is unknown if persistent BMD deficits are present in high level collegiate athletes. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate bilateral changes in the BMD of the femur and tibia from before the injury to 24 months after ACLR in collegiate athletes. We hypothesized that the BMD of both the distal femur and the proximal tibia would be significantly reduced within the surgical limb initially postoperatively but return to preinjury levels by 24 months after ACLR. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 33 Division I collegiate athletes were identified between 2010 and 2021 (13 female) who underwent total body dual-energy X-ray absorptiometry (DXA) before sustaining an ACL injury. DXA was repeated at 6, 12, and 24 months after ACLR. Linear mixed effects models assessed differences in the BMD at 5%, 15%, and 50% of the femur's length (F5, F15, F50) and at 5%, 15%, and 50% of the tibia's length (T5, T15, T50) within each limb from before the injury to 24 months after ACLR, reported as Tukey-adjusted P values. RESULTS: Compared with before the injury, the BMD at F5 of the surgical limb was reduced by 0.15 g/cm2 (SE, 0.02 g/cm2) at 6 months (P < .001). The BMD at F15 of the surgical limb was reduced by 0.06 g/cm2 (SE, 0.01 g/cm2), 0.09 g/cm2 (SE, 0.01 g/cm2), and 0.09 g/cm2 (SE, 0.01 g/cm2) at 6, 12, and 24 months, respectively (all P < .001). The BMD at T5 of the nonsurgical limb was reduced by 0.07 g/cm2 (SE, 0.02 g/cm2) at 12 months (P = .02) and 0.10 g/cm2 (SE, 0.02 g/cm2) at 24 months (P = .001). The BMD at T15 of the surgical limb was reduced by 0.07 g/cm2 (SE, 0.01 g/cm2) at 6 months and 0.08 g/cm2 (SE, 0.02 g/cm2) at 12 months (P < .001). CONCLUSION: BMD deficits at F15 of the surgical limb persisted out to 24 months (-7.1%) after ACLR compared with before the injury in collegiate athletes. The BMD at F5 and T15 of the surgical limb was reduced at 6 and 12 months but not at 24 months compared with preinjury levels. For the nonsurgical limb, no significant differences were detected, except for the T5 region at 12 months (-5.1%) and 24 months (-7.2%). The BMD at F50 and T50 of both limbs was not significantly different than preinjury levels at any time after ACLR.

Canine ACL rupture: a spontaneous large animal model of human ACL rupture.

BACKGROUND: Anterior cruciate ligament (ACL) rupture in humans is a common condition associated with knee pain, joint instability, and secondary osteoarthritis (OA). Surgical treatment with an intraarticular graft provides reasonable outcomes at mid and long-term follow-up. Non-modifiable and modifiable factors influence risk of ACL rupture. The etiology, mechanobiology, causal biomechanics, and causal molecular pathways are not fully understood. The dog model has shared features of ACL rupture that make it a valuable spontaneous preclinical animal model. In this article, we review shared and contrasting features of ACL rupture in the two species and present information supporting spontaneous canine ACL rupture as a potentially useful preclinical model of human ACL rupture with a very large subject population. RESULTS: ACL rupture is more common in dogs than in humans and is diagnosed and treated using similar approaches to that of human patients. Development of OA occurs in both species, but progression is more rapid in the dog, and is often present at diagnosis. Use of client-owned dogs for ACL research could reveal impactful molecular pathways, underlying causal genetic variants, biomechanical effects of specific treatments, and opportunities to discover new treatment and prevention targets. Knowledge of the genetic contribution to ACL rupture is more advanced in dogs than in humans. In dogs, ACL rupture has a polygenetic architecture with moderate heritability. Heritability of human ACL rupture has not been estimated. CONCLUSION: This article highlights areas of One Health research that are particularly relevant to future studies using the spontaneous canine ACL rupture model that could fill gaps in current knowledge.

Medial Patellofemoral Ligament Repair for Recurrent Patellar Instability: Successful Outcomes Among Patients With Low Coronal Malalignment and Normal Patellar Height.

Medial patellofemoral ligament (MPFL) repair is discouraged for the treatment of chronic, recurrent patellar instability (RPI) because of high reported failure rates. However, the senior author uses MPFL repair for chronic RPI in the setting of low tibial tubercle-trochlear groove (TT-TG) distance. In this retrospective case series, we report results and evaluate outcome predictors. We used billing records to identify all patients, 14 years or older, who underwent isolated repair for chronic RPI performed by a single surgeon between September 2010 and February 2019. The TT-TG distance, patellar height (Caton-Deschamps Index [CDI]), and trochlear depth were measured on preoperative magnetic resonance imaging; postoperative reports were reviewed; and post hoc Kuala scores were obtained to extend outcome length. Patellar dislocation or revision surgery was considered a failure. Nonfailures were categorized as excellent or fair, based on the most recent report. Univariable generalized estimating equation models were used to evaluate associations of predictors (radiographic parameters, age, ligamentous laxity, primary presenting complaint) with failure and/or success. A total of 93 isolated MPFL repairs were performed. After exclusions were made for workers' compensation insurance (n=4), substance abuse (n=3), major secondary trauma less than 3 months postoperatively (n=3), and follow-up of less than 12 months (n=42), 41 knees (38 patients) had median follow-up of 32 months (interquartile range, 19-48 months). All repairs were patellar sided. Outcomes for 4 knees were considered failures, 23 were excellent, and 14 were fair. Only increased CDI was associated with increased risk of failure (odds ratio, 1.70; 95% CI, 0.98-2.92; P=.06). Mean CDI was 1.23 mm (SD, 0.13 mm) for failures vs 1.08 mm (SD, 0.16 mm) for nonfailures. Failure rate was less than 10% following patellar-sided MPFL repair for treatment of chronic RPI among patients with low TT-TG distance. Increased patellar height was associated with higher risk of failure. [Orthopedics. 2022;45(1):e23-e29.].

The Forum, Society for Women Sports Medicine Orthopaedic Surgeons.

The Forum is a private, not-for-profit organization for board-certified, fellowship-trained, female orthopaedic surgeons. Founded in 1999, The Forum was conceived as a partnership with women in industry, designed to support women orthopaedic surgeons by providing a place to share research and practice ideas and to stimulate interest and research in arthroscopic surgery. Membership has grown from a handful of founding members to nearly 100 strong in 2021. An annual meeting is held over Martin Luther King, Jr., weekend each year, combining scientific and social programs and highlighted by the Sandy Kirkley Memorial Lecture. The Forum has recently gained notoriety through the work of some of its members in advocating for the protection of athletes from sexual abuse and the publication of the first position statement on the topic, subsequently endorsed by the American Academy of Orthopaedic Surgeons. A recent partnership with the American Orthopaedic Society for Sports Medicine and the Arthroscopy Association of North America to provide concurrent sessions at the 2021 combined annual meeting has increased the visibility of the society and its members.

Next Steps: Advocating for Women in Orthopaedic Surgery.

Orthopaedic surgery is the least diverse of all medical specialties, by both sex and race. Diversity among orthopaedic trainees is the lowest in medicine, and growth in percentage representation is the lowest of all surgical subspecialties. Women comprise only 6% of orthopaedic surgeons and 16% of orthopaedic surgery trainees. This extreme lack of diversity in orthopaedics limits creative problem-solving and the potential of our profession. Women in orthopaedics encounter sexual harassment, overt discrimination, and implicit bias, which create barriers to training, career satisfaction, and success. Women are underrepresented in leadership positions, perpetuating the lack of diversity through poor visibility to potential candidates, which impedes recruitment. Correction will require a concerted effort, as acknowledged by the American Academy of Orthopaedic Surgeons leadership who included a goal and plan to increase diversity in the 2019 to 2023 Strategic Plan. Recommended initiatives include support for pipeline programs that increase diversity of the candidate pool; sexual harassment and implicit bias acknowledgement, education, and corrective action; and the active sponsorship of qualified, capable women by organizational leaders. To follow, women will lend insight from their diverse viewpoints to research questions, practice problems, and clinical conundrums of our specialty, augmenting the profession and improving patient outcomes.

A 2-yr, School-Based Resistance Exercise Pilot Program Increases Bone Accrual in Adolescent Girls.

PURPOSE: The current analysis evaluates cumulative benefits after year two (Y2) of a school-based resistance training intervention. METHODS: Adolescent girls were enrolled and measured at the beginning of 6th grade (baseline, BL) and again at 1st follow-up (FU1: Y1 end) and 2nd follow-up (FU2: Y2 end). School gym classes met alternate school days. Site 1 had standard gym classes (CON). Site 2 gym classes included 8-12 minutes of resistance training (INT); INT girls were categorized based on observed participation effort and time (LO, HI). Measurements included: 1) height and weight; 2) questionnaires to assess extracurricular exercise and diet (calcium, vitamin D); 3) dual-energy X-ray absorptiometry (DXA, Lunar Prodigy). Whole body less head (SUB) scans yielded bone mineral content (BMC) and body composition. Lumbar spine (L1-L4) and femoral neck (FN) scans yielded BMC and areal bone mineral density (BMD); radius scans yielded ultradistal and 1/3 BMD. ANCOVA compared group means for percent gains from BL to FU2, accounting for biological maturity, BL height, height change, inter-scan interval, organized activity, calcium and vitamin D. RESULTS: In 62 girls (21 CON, 41 INT), intention to treat analyses detected INT vs. CON advantages for L1-L4 BMC and BMD (4.1%, 5.6%: p<0.05). HI effort participants (n=19) demonstrated advantages for BMC and BMD at L1-L4 and FN (5.7% to 8.2%, p<0.01) vs. CON. CONCLUSIONS: Over two school years, this resistance intervention yielded lumbar spine advantages; enthusiastic participation (HI) yielded lumbar spine and femoral neck advantages. Further work is warranted to evaluate benefit persistence after intervention cessation.

Circum-menarcheal bone acquisition is stress-driven: A longitudinal study in adolescent female gymnasts and non-gymnasts.

Mechanical loading through youth exercise is highly modifiable and represents a strategy to maximize peak adult bone mass, with the potential for broad implementation across the population to lower fracture risk. For girls, circum-menarcheal growth is critical, with around 50% of adult bone acquired over a 4-year period. Here, we prospectively followed 10 gymnasts and 12 age-matched non-gymnasts across approximately 4 years circum-menarche. A combination of pQCT and subject-specific finite element models were used to measure differences in bone acquisition and structure between the groups, and to determine the degree to which specific mechanical factors predict change in bone structure. At baseline, gymnasts had stronger bone, including 26% higher BMC, 51% greater compressive strength, and 21% higher trabecular density. Over the study period, both groups more than doubled their bone strength. Pre-menarcheal principal stresses predicted change in pQCT variables for non-gymnasts, but not gymnasts. The bone of non-gymnasts became more asymmetrical than the bone of gymnasts. Our results suggest that exposure to the diverse, intense mechanical signals of gymnastic loading during adolescence imparts substantial benefits to bone geometry and mechanical function. Specifically, the bone of gymnasts is better able to resist loading from multiple directions, and operates with a higher factor of safety compared to non-gymnasts.