Lumbopelvic Biomechanics and Muscle Performance in Individuals with Unilateral Transfemoral Amputation: Implications for Lower Back Pain

Many people with lower extremity amputation (LEA) experience lower back pain (LBP). The amount of pain they experienced can be debilitating and severely interferes with activities of daily living. Previous studies have explored LBP in populations without LEA, and the evidence is also growing within the limb loss population. However, the mechanism for the high prevalence of LBP after LEA remains unclear. The lower back muscles, specifically the multifidi muscles, play an important role in stabilization of the spine during motion, and LBP has been associated with decreased mobility in patient populations, but the degree of dysfunction in the spinal muscles related to the presence of LBP has not been quantified in individuals with LEA. Therefore, in this dissertation, we first developed and tested the reliability of a clinical-based test that may help clinicians to see where mobility deficits may be present in the LEA population with and without LBP (Chapter 2), thus potentially guiding treatment plans to incorporate targeted training. We also assessed the multifidi muscle activity to determine if there are differences in activity levels between those who have LBP and those who do not have LBP during a functional task.One of the characteristics of a muscle that is associated with strength and stability is its thickness. Generally, the thicker the muscle, the stronger it is. Understanding the thickness and activity of these multifidus muscles during submaximal contractions is key to understand the morphology of the paraspinal muscle in response to LBP. One readily available tool to assess muscle thickness is musculoskeletal ultrasound imaging (USI). USI has not been widely used to examine this population, specifically those with LEA and LBP. Therefore, in Chapter 3, we first sought to establish reliability of USI in this population. We then used USI to measure the thickness of the multifidus muscles in those with LEA and LBP and those without LBP, both at rest and during submaximal contractions, to compare between groups to see if there are differences in the thicknesses of the muscles associated with the presence of LBP. Two key aspects of muscle performance are strength and fatigability, especially in muscles that are designed for stability like the multifidi muscles. Thus, in Chapter 4, we tested spinal extensor strength and endurance using standardized clinical tests. We then examined the multifidi activity level during the endurance test as a percentage of their maximal activation. In this study, we examined whether those who reported LBP experienced fatigue earlier than those who do not have pain. We also compared muscle activation between the groups. Overall, our findings suggest that there may be differences in the multifidi muscles between those with LEA and LBP and those with LEA and no LBP. The two tests (i.e., reaching tests and USI measurement for muscle thickness) we implemented in this population were shown to be reliable. Furthermore, our results showed that individuals with LEA and LBP exhibited significant deficits in reaching and muscle endurance performance. We believe these data are valuable as benchmarks for continuing to build the evidence in this area

Osteoarthritis Disease Severity in the Temporomandibular Joint and the Knee Joint: A Comparative Cadaveric Study

OBJECTIVE: The objective of this study was to determine the level of disease severity in a pilot cohort of temporomandibular joints (TMJs) and compare them to the pathology findings previously characterized in cadaveric knee joints. DESIGN: Thirty-one intact TMJs from 17 cadaveric donors were harvested and arthritic lesioning seen in the knee joint was investigated on the condyle and the fossa of the TMJ. Prevalence of gross alterations was equated and disease severity was determined for sex- and age-based donor pools using a validated, osteoarthritis (OA) disease severity scale (DSS). Knee joint DSS scores were also compared to the TMJ condyle and fossa DSS scores and a case study was carried out on a male donor that demonstrated severe OA in the both joints. RESULTS: The mandibular fossa demonstrated an increase in disease severity compared to the mandibular condyle in a mixed sex donor pool ( CONCLUSIONS: This study demonstrates that gross signs of OA in the TMJs of cadavers are comparable to pathology found in the knee. The mandibular fossa appears to be the site of more profound disease, implying translational movements may be more likely to induce biomechanically abnormal movement, loading, and OA

Comparison of Clinical and Biomechanical Characteristics Between Individuals With Lower Limb Amputation With and Without Lower Back Pain: A Systematic Review and Meta-Analysis

Background Lower back pain is a debilitating condition common to individuals with lower limb amputation. It is unclear what risk factors contribute to the development of back pain. This study systematically reviewed and analyzed the available evidence regarding the clinical and biomechanical differences between individuals with amputation, with and without lower back pain. Methods A literature search was conducted in PubMed, Web of Science, Scopus, and CINAHL databases in November 2020 and repeated in June 2021 and June 2022. Studies were included if they reported comparisons of demographic, anthropometric, biomechanical, and other clinical variables between participants with and without LBP. Study quality and potential for reporting bias were assessed. Meta-analyses were conducted to compare the two groups. Findings Thirteen studies were included, with aggregated data from 436 participants (239 with LBP; 197 pain free). The median reporting quality score was 37.5%. The included studies enrolled participants who were predominantly male (mean = 91.4%, range = 77.8–100%) and with trauma-related amputation. Meta-analyses showed that individuals with LBP exhibited moderate (3.4 out of 10) but significantly greater pain than those without LBP. We found no between-group differences in age, height, weight, BMI, and time since amputation (p = 0.121–0.682). No significant differences in trunk/pelvic kinematics during gait were detected (p = 0.07–0.446) between the groups. Interpretation Demographic, anthropometric, biomechanical, and simple clinical outcome variables may be insufficient for differentiating the risk of developing back pain after amputation. Investigators should be aware of the existing gender bias in sampling and methodological limitations, as well as to consider incorporating psychosocial measures when studying LBP in this clinical population