Pregnancy Results in Lasting Changes in Knee Joint Laxity

Return to Running for Postpartum Elite and Subelite Athletes

CONTEXT

There is little evidence to guide elite athletes who desire returning to competition after giving birth to a child. Ultimately, this can result in decreased performance and increased risk of injury. This paper addresses aspects that must be considered when building and monitoring a return to running program for a postpartum elite or subelite athlete, including pelvic floor and core stability, progressive reloading of the musculoskeletal system, monitoring of nutritional parameters, and considerations for lactation.

EVIDENCE ACQUISITION

PubMed and CINAHL (Cumulative Index for Nursing and Allied Health Literature) were searched with the following search strategy: (extreme sports OR elite athletes OR running OR exercise) AND (breastfeeding OR lactation OR bone density OR fetal weight OR gestational weight gain OR postpartum or post-partum OR postnatal OR post-natal OR pregnancy OR childbirth). The following information is based on best available evidence and clinical experience.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Due to the interplay between cardiovascular fitness, postpartum nutrition, lactation, and progressive reloading of the muscular and skeletal system, we propose a multimodal, multidisciplinary approach to safely and successfully allow an athlete to return to an elite level of competition.

CONCLUSION

Return to running in the postpartum period is a highly individualized process that benefits from multidisciplinary, individualized care. This includes monitoring of nutrition, core and pelvic floor function, bone reloading, muscle and tendon reloading, and breastfeeding care when applicable.

STRENGH OF RECOMMENDATION TAXONOMY (SORT)

C.

Are physical fitness, a history of childbirth and injury history related to knee valgus in female Canadian Armed Forces members during a bodyweight overhead squat movement?

OBJECTIVES

A history of childbirth is associated with musculoskeletal injury (MSKi) in female members of the Canadian Armed Forces (CAF). While previous injury and pregnancy impact knee kinematics, it is unclear if a history of childbirth is associated with medial knee displacement (MKD) in an overhead squat movement screen. The aim of this study is to examine the relationship between MKD and (1) MSKi and (2) parity status in female CAF members.

METHODS

24 nulliparous and 21 parous female participants employed by the CAF completed a comprehensive physical fitness assessment of muscular flexibility, power, strength, endurance, aerobic capacity and a bodyweight overhead squat movement screen (recorded using two-dimensional video, and hip-knee-ankle angle measured using Kinovea software). Interactions between MKD, parity status and MSKi history were assessed by one-way analysis of variance and two-way analysis of covariance (ANCOVA) (adjusted for age).

RESULTS

An interaction between parity status and acute injury of the lower extremity was observed (F=4.379, p=0.043, η2 =0.099) in MKD of the right knee. The two-way ANCOVA examining acute injury of the lumbopelvic hip complex (lower back, pelvis, hip) yielded an interaction between acute injury to the lumbopelvic hip complex and parity status (F=4.601, p=0.038, η2=0.103) in MKD asymmetry.

DISCUSSION

Parous participants with acute injury to the lower extremity had larger MKD than parous without this injury type. Parous participants without acute injury to the lumbopelvic hip complex had greater MKD asymmetry than nulliparous without this injury type. Our findings suggest that researchers and clinicians should consider parity status in conjunction with MSKi history when assessing knee kinematics in female military members.

Long-Term Effects of Reproduction and Lactation on the Rat Supraspinatus Tendon and Proximal Humerus

During pregnancy and breastfeeding, women undergo hormonal fluctuations required for fetal development, parturition, and infant growth. These changes have secondary consequences on the maternal musculoskeletal system, increasing the risk for joint pain and osteoporosis. Though hormone levels return to prepregnancy levels postpartum, women may experience lasting musculoskeletal pain. Sex disparities exist in the prevalence of musculoskeletal disorders, but it remains unclear how reproductive history may impact sex differences. Specifically, the effects of both reproductive history and sex on the rotator cuff have not been studied. Pregnancy and lactation affect bone microstructure, suggesting possible impairments at the enthesis of rotator cuff tendons, where tears commonly occur. Therefore, our objective was to evaluate how reproductive history affects sex differences of the supraspinatus tendon and proximal humerus using male, virgin female, and female rats with a history of reproduction (referred to as reproductive females). We hypothesized tendon mechanical properties and humeral bone microstructure would be inferior in reproductive females compared to virgin females. Results showed sex differences independent of reproductive history, including greater tendon midsubstance modulus but lower subchondral bone mineral density (BMD) in females. When considering reproductive history, reproductive rats exhibited reduced tendon insertion site modulus and trabecular bone micro-architecture compared to virgin females with no differences from males. Overall, our study identified long-term changes in supraspinatus tendon mechanical and humeral trabecular bone properties that result following pregnancy and lactation, highlighting the importance of considering reproductive history in investigations of sex differences in the physiology and pathology of rotator cuff injuries.

Sex differences in osteoarthritis prevalence, pain perception, physical function and therapeutics

OBJECTIVE

Women have a higher prevalence of osteoarthritis (OA) and worse clinical courses than men. However, the underlying factors and therapeutic outcomes of these sex-specific differences are incompletely researched. This review examines the current state of knowledge regarding sex differences in OA prevalence, risk factors, pain severity, functional outcomes, and use and response to therapeutics.

METHODS

PubMed database was used with the title keyword combinations "{gender OR sex} AND osteoarthritis" plus additional manual search of the included papers for pertinent references, yielding 212 references. Additional references were added and 343 that were reviewed for appropriateness.

RESULTS

Globally, women account for 60% of people with osteoarthritis with a greater difference after age 40. The higher risk for women may be due to differences in joint anatomy, alignment, muscle strength, hormonal influences, obesity, and/or genetics. At the same radiographic severity, women have greater pain severity than men, which may be explained by biologically distinct pain pathways, differential activation of central pain pathways, differences in pain sensitivity, perception, reporting, and coping strategies. Women have greater limitations of physical function and performance than men independent of BMI, OA severity, injury history, amount of weekly exercise. Women also have greater use of analgesic medications than men but less use of arthroplasty and poorer prognosis after surgical interventions.

CONCLUSIONS

The recognition of sex differences in OA manifestations and management could guide tailoring of sex-specific treatment protocols, and analysis of sex as a biological variable in future research would enhance development of precision medicine.

The Combined Influence of Infant Carrying Method and Motherhood on Gait Mechanics

Postpartum mothers are susceptible to lumbopelvic pain which may be exacerbated by loading, like carrying their infant in arms and with baby carriers. Nulliparous women carrying infant mannequins may biomechanically mimic mother-infant dyad, but this has not been studied. The purpose of our study was to investigate biomechanical differences of 10 mothers carrying their infants and 10 nulliparous women carrying infant mannequins under 3 gait conditions: carrying nothing, carrying in arms, and carrying in a baby carrier (babywearing). Spatiotemporal gait parameters, peak ground reaction forces and impulses, and lower extremity and trunk kinematics were collected using motion capture and force plates and compared using a mixed 2 × 3 (parity × condition) analysis of variance (α ≤ .05). The largest differences occurred between carrying conditions: carrying in arms or babywearing increased vertical and anteroposterior ground reaction forces, trunk extension, ankle dorsiflexion, and hip and knee flexion. Kinematic differences were identified between arms and babywearing conditions. Together this suggests alterations in joint loading for both groups. Our study also contributes a novel understanding of postpartum health by demonstrating alterations in step time, anterior forces, and ankle and knee mechanics, suggesting that during gait, mothers carrying their own infants choose different propulsive strategies than nulliparous women carrying mannequins.

The Influence of Multiple Pregnancies on Gait Asymmetry: A Case Study

Gait asymmetry is a predictor of fall risk and may contribute to increased falls during pregnancy. Previous work indicates that pregnant women experience asymmetric joint laxity and pelvic tilt during standing and asymmetric joint moments and angles during walking. How these changes translate to other measures of gait asymmetry remains unclear. Thus, the purpose of this case study was to determine the relationships between pregnancy progression, subsequent pregnancies, and gait asymmetry. Walking data were collected from an individual during 2 consecutive pregnancies during the second and third trimesters and 6 months postpartum of her first pregnancy and the first, second, and third trimesters and 6 months postpartum of her second pregnancy. Existing asymmetries in step length, anterior-posterior (AP) impulses, AP peak ground reaction forces, lateral impulses, and joint work systematically increased as her pregnancy progressed. These changes in asymmetry may be attributed to pelvic asymmetry, leading to asymmetric hip flexor and extensor length, or due to asymmetric plantar flexor strength, as suggested by her ankle work asymmetry. Relative to her first pregnancy, she had greater asymmetry in step length, step width, braking AP impulse, propulsive AP impulse, and peak braking AP ground reaction force during her second pregnancy, which may have resulted from increased joint laxity.

Osteoarthritis as an Umbrella Term for Different Subsets of Humans Undergoing Joint Degeneration: The Need to Address the Differences to Develop Effective Conservative Treatments and Prevention Strategies

Osteoarthritis (OA) of joints such as the knee and hip are very prevalent, and the number of individuals affected is expected to continue to rise. Currently, conservative treatments after OA diagnosis consist of a series of increasingly invasive interventions as the degeneration and pain increase, leading very often to joint replacement surgery. Most interventions are focused on alleviating pain, and there are no interventions currently available that stop and reverse OA-associated joint damage. For many decades OA was considered a disease of cartilage, but it is now considered a disease of the whole multi-tissue joint. As pain is the usual presenting symptom, for most patients, it is not known when the disease process was initiated and what the basis was for the initiation. The exception is post-traumatic OA which results from an overt injury to the joint that elevates the risk for OA development. This scenario leads to very long wait lists for joint replacement surgery in many jurisdictions. One aspect of why progress has been so slow in addressing the needs of patients is that OA has been used as an umbrella term that does not recognize that joint degeneration may arise from a variety of mechanistic causes that likely need separate analysis to identify interventions unique to each subtype (post-traumatic, metabolic, post-menopausal, growth and maturation associated). A second aspect of the slow pace of progress is that the bulk of research in the area is focused on post-traumatic OA (PTOA) in preclinical models that likely are not clearly relevant to human OA. That is, only ~12% of human OA is due to PTOA, but the bulk of studies investigate PTOA in rodents. Thus, much of the research community is failing the patient population affected by OA. A third aspect is that conservative treatment platforms are not specific to each OA subset, nor are they integrated into a coherent fashion for most patients. This review will discuss the literature relevant to the issues mentioned above and propose some of the directions that will be required going forward to enhance the impact of the research enterprise to affect patient outcomes.

Sex Differences in Biological Systems and the Conundrum of Menopause: Potential Commonalities in Post-Menopausal Disease Mechanisms

Sex-specific differences in biology and physiology likely start at the time of conception and progress and mature during the pre-puberty time frame and then during the transitions accompanying puberty. These sex differences are impacted by both genetics and epigenetic alterations during the maturation process, likely for the purpose of preparing for successful reproduction. For females, later in life (~45–50) they undergo another transition leading to a loss of ovarian hormone production at menopause. The reasons for menopause are not clear, but for a subset of females, menopause is accompanied by an increased risk of a number of diseases or conditions that impact a variety of tissues. Most research has mainly focused on the target cells in each of the affected tissues rather than pursue the alternative option that there may be commonalities in the development of these post-menopausal conditions in addition to influences on specific target cells. This review will address some of the potential commonalities presented by an integration of the literature regarding tissue-specific aspects of these post-menopausal conditions and data presented by space flight/microgravity (a condition not anticipated by evolution) that could implicate a loss of a regulatory function of the microvasculature in the risk attached to the affected tissues. Thus, the loss of the integration of the paracrine relationships between endothelial cells of the microvasculature of the tissues affected in the post-menopausal environment could contribute to the risk for post-menopausal diseases/conditions. The validation of this concept could lead to new approaches for interventions to treat post-menopausal conditions, as well as provide new understanding regarding sex-specific biological regulation.

Impact of parity on biomechanical risk factors for knee OA initiation

BACKGROUND

Women are twice as likely as men to develop knee osteoarthritis (OA), and with it experience greater losses of physical function and disability. A change in the mechanical environment of the joint is a key initiating factor for knee OA. Differences in morphology, joint injury risk, and hormonal shifts in mid-life are often considered factors which increase OA risk for women. Pregnancy, a time of significant hormonal, morphological, and biomechanical change, has received comparably less attention. If morphological and biomechanical changes persist postpartum, this could increase OA risk for parous (childbearing) women.

RESEARCH QUESTION

Are lower limb gait mechanics different between healthy nulliparous (non-childbearing) and parous (childbearing) women?

METHODS

Twenty-eight self-reported not pregnant female participants (14 parous, 14 nulliparous) were recruited for the study. Nulliparous participants had never given birth to a child. Parous participants had given birth to at least one full-term infant (37-42 weeks) without complications between one to five years before data collection. Motion capture of participants' preferred, fast, and set (1.4 m/s) walking speeds was conducted. Repeated measures ANOVA were performed to test for significant group differences in joint kinematics and kinetics.

RESULTS

There was a significant main effect of group indicating a larger knee flexion angle at toe off (p = 0.0002), smaller knee extension moment at heel strike (p = 0.0006), smaller first peak knee flexion moment (p = 0.040), and smaller peak hip adduction moment for the parous group compared to the nulliparous group (p = 0.003). Static Q-angle did not differ between groups.

SIGNIFICANCE

Alteration in mechanics from the habitual loading pattern are thought to increase risk of OA. Smaller knee moments in post-partum women could alter the mechanical stimulus to cartilage, and should be investigated in conjunction with cartilage health measures to determine the link with OA initiation.

Common musculoskeletal impairments in postpartum runners: an international Delphi study

Background

Postpartum runners report musculoskeletal pain with running. Because of inadequate research, little is known about the origin and pain-related classification. Through expert consensus, this study is the first attempt to understand the musculoskeletal impairments that these runners present with. The objective of this survey was to gather expert consensus on characteristics of reported impairments in postpartum runners that have musculoskeletal pain.

Methods

A web-based Delphi survey was conducted and was composed of five categories: strength, range of motion, alignment and flexibility impairments, as well as risk factors for pain in postpartum runners.

Results

A total of 117 experts were invited. Forty-five experts completed round I and forty-one completed rounds II and III. The strength impairments that reached consensus were abdominal, hip and pelvic floor muscle weakness. The range of motion impairments that reached consensus were hip extension restriction, anterior pelvic tilt and general hypermobility. The alignment impairments that reached consensus were a Trendelenburg sign, dynamic knee valgus, lumbar lordosis, over-pronation and thoracic kyphosis. The flexibility impairments that reached consensus were abdominal wall laxity, and tightness in hip flexors, lumbar extensors, iliotibial band and hamstrings. The risk factors for pain in postpartum runners were muscular imbalance, poor lumbopelvic control, too much too soon, life stressors, pain during pregnancy and pelvic floor trauma.

Conclusion

This study presents a framework for clinicians to understand pain in postpartum runners and that can be investigated in future cohort studies.

Level of evidence

5.

Association of Reproductive History With Motor Function and Disability in Aging Women

BACKGROUND/OBJECTIVES

The associations of reproductive history and motor function are controversial.

DESIGN

Prospective cohort study with 10 years of follow-up.

SETTING

Three French cities between 1999 and 2011.

PARTICIPANTS

A total of 3043 community-dwelling women from the Three-City Dijon study population.

MEASUREMENTS

We examined the cross-sectional and longitudinal association of age at menopause, artificial menopause, and parity with walking speed (WS) using linear regression and linear mixed models, respectively. Cox proportional models were used to examine the association of characteristics of reproductive life with disability.

RESULTS

Mean baseline WS was 143.8 cm/s. Artificial menopause was associated with slower WS at baseline (β = -3.29; 95% confidence interval [CI] = -5.83 to -0.74; P = .01). Reproductive life characteristics had no effect on change in WS. Increasing age at menopause was associated with reduced disability risk (hazard ratio [HR] for 5-year increase = 0.92; 95% CI = 0.87-0.99; P = .02), while parity increased disability risk (HR for ≥3 vs 0 children = 1.53; 95% CI = 1.22-1.93; P < .01).

CONCLUSION

These findings show that early age at menopause and higher parity have a deleterious effect on motor function that persists in older people. J Am Geriatr Soc 68:585-594, 2020.

Static and dynamic effects of customized insoles on attenuating arch collapse with pregnancy: A randomized controlled trial

INTRODUCTION

Anthropometric changes to the feet with pregnancy may increase risk for musculoskeletal disease. Customized arch-supportive orthoses to prevent anthropometric changes could potentially provide an inexpensive means to prevent musculoskeletal impairments and improve quality of life for women during their post-reproductive years. The objective of this prospective, randomized controlled trial was to determine whether customized foot orthoses can prevent arch collapse during pregnancy.

MATERIALS AND METHODS

Seventy-two first trimester women (age 18-40) were randomized to wear either their usual footwear (control) or their usual footwear with custom-molded arch-supportive orthoses. Each participant in the customized orthosis group had orthoses customized by a certified orthotist. Baseline assessments were completed during the first trimester and follow-up assessments were completed approximately 8 weeks postpartum. The primary outcome measurements were static arch height index (AHI), arch drop, arch rigidity index, and center of pressure excursion index (CPEI).

RESULTS

There were no statistically significant differences in the change in static foot structure or dynamic arch function between baseline and follow-up within either group. Comparing the customized orthosis and control groups, no significant differences were detected in change in AHI sitting (p=.44), AHI standing (p=.48), arch drop (p=.67), arch rigidity (p=.68) or CPEI (p=.77).

CONCLUSIONS

There was no difference in arch change when comparing women who were randomized to wear customized orthoses or self-selected footwear. The finding of no arch drop in either group may indicate that both groups supported their arches during the study period or that neither group was predisposed to lose arch height with pregnancy.