Increased trunk flexion may underlie elevated knee flexor activity in people with knee osteoarthritis

BackgroundPrevious research has demonstrated elevated activation of the knee flexor muscles in people with knee osteoarthritis. People with this condition have also been observed to walk with increased trunk flexion; this may alter biomechanical loading patterns and change muscle activation profiles. Therefore, the aim of this study was to understand the biomechanical effect of increasing trunk flexion during walking.MethodsKinetic and EMG data were collected from a sample of 20 people with knee osteoarthritis and a sample of 20 healthy matched controls during normal walking. Using a biofeedback protocol, participants were subsequently instructed to walk with a 5° increase in trunk flexion. Sagittal moments, muscle activations and co-contractions were then compared across a window in early stance with a two-way ANOVA test.ResultsWhen trunk flexion was increased, there was a corresponding increase in activity of the medial and lateral hamstrings and gastrocnemius muscles as well as a rise in medial co-contraction. This effect was consistent across the two groups. The most pronounced effect was observed for semitendinosus, which showed a dramatic change in activation profile in the healthy group and a 127% increase in activation during early stance.ConclusionsThis is the first study to demonstrate that increased trunk flexion in people with knee osteoarthritis may explain, to some degree, the elevated knee flexor activity and medial co-contraction which is associated with this disease. These findings motivate further work to understand the therapeutic potential of interventions designed to improve postural alignment.     

Characteristics of the descending genicular artery blood flow velocity in patients with knee osteoarthritis

BackgroundIn patients with knee osteoarthritis (KOA), the descending genicular artery (DGA) showed abnormal angiogenesis. However, the non-invasive assessment method of DGA remains unclear. The aim of this study was to clarify the characteristics of blood flow velocity of the DGA in patients with KOA and to examine the factors involved in the changes.MethodsThe KOA group included 22 knees of 22 patients with KOA (4 males, 18 females; mean age, 72.3 ± 7.5 years) and the control group included 22 knees (4 males, 18 females; mean age, 71.3 ± 5.4 years) of 22 healthy adults. The peak systolic blood flow velocity (PSV) in each group was measured using ultrasonography. The KOA group was classified into the effusion group and the non-effusion group based on observed effusion, and the PSV was compared between the two groups. The relationships between PSV and suprapatellar bursa intracavitary distance, pain, femorotibial angle, Japanese Knee Osteoarthritis Measure were also investigated.ResultsThe PSV in the KOA group (51.5 ± 12.9 cm/s) was significantly higher than that in the control group (29.3 ± 4.4 cm/s) (P < 0.01). In the KOA group, PSV in the effusion group (55.5 cm/s (51.2–59.4 cm/s)) was significantly higher than that in the non-effusion group (39.1 cm/s (35.1–44.4 cm/s)) (P < 0.01). The PSV was positively and significantly correlated with both suprapatellar bursa intracavitary distance (r = 0.81: P < 0.01) and pain (r = 0.48: P < 0.05).ConclusionsThe PSV measurement in the DGA is useful for the evaluation of non-invasive synovitis of patients with KOA.     

Quality-of-life and postoperative satisfaction following pseudoarthrectomy in patients with Bertolotti syndrome

BACKGROUND CONTEXTBertolotti syndrome is a clinical diagnosis given to patients with back pain arising from a lumbosacral transitional vertebra (LSTV). A particular class of LSTV involves a pseudoarticulation between the fifth lumbar transverse process and the sacral ala, and surgical resection of the pseudoarticulation may be offered to patients failing conservative management. Bertolotti syndrome is still not well understood, particularly regarding how patients respond to surgical resection of the LSTV pseudoarticulation.PURPOSETo examine change in quality-of-life (QOL) and patient satisfaction following surgical resection of the LSTV pseudoarticulation in patients with Bertolotti syndrome.DESIGNAmbidirectional observational cohort study of patients seen at a single institution's tertiary spine center over a 10-year period.PATIENT SAMPLECohort consisted of 31 patients with Bertolotti Syndrome who underwent surgical resection of the pseudoarticulation.OUTCOME MEASURESPreoperative and postoperative Patient-Reported Outcomes Measurement Information System Global Health (PROMIS-GH) Mental and Physical Health T-scores, and a single-item postoperative satisfaction questionnaire.METHODSPatients were identified through diagnostic and procedural codes. Immediate preoperative PROMIS-GH scores available in the chart were gathered retrospectively, and postoperative PROMIS-GH and satisfaction scores were gathered prospectively through a mail-in survey.RESULTSMean (SD) improvement of PROMIS-GH Physical Health T-score was 8.7 (10.5) (p<.001). Mean (SD) improvement of PROMIS-GH Mental Health T-scores was 5.9 (9.2) (p=.001). When stratifying PROMIS-GH T-scores by response to the patient satisfaction survey, there were significant group differences in mean change for Physical Health T-scores (p<.001), and Mental Health T-score (p=.009). Patients who stated, “The treatment met my expectations” had much greater mean improvement in the PROMIS-GH T-scores.CONCLUSIONSPatients undergoing a pseudoarticulation resection procedure may experience a significant improvement in quality-of-life as measured by PROMIS-GH Mental and Physical Health.     

Feasibility,correlates, and validity of the one-leg sit-to-stand test in individuals following anterior cruciate ligament reconstruction

ObjectiveRegular quadriceps strength assessment is important following anterior cruciate ligament reconstruction (ACLR). The one-leg sit-to-stand (OLSTS) test potentially overcomes the barrier of accessibility to specialised testing equipment. However, feasibility and validity testing of OLSTS is lacking in the ACLR population. This study aims to examine the feasibility, correlates, and predictive validity of OLSTS with self-reported running and jumping difficulty in individuals post-ACLR.DesignRetrospective longitudinal study.Methods20 patients with primary unilateral ACLR were tested at 6-months and 1-year post-ACLR. Feasibility was assessed by the number of patients who had safely performed OLSTS at both timepoints. Cross-sectional gender-adjusted Spearman correlations of OLSTS with quadriceps strength, physical impairments, and psychological variables were measured at 6-months. Predictive validity was assessed via ordinal regression, quantifying the associations of OLSTS with self-reported running and jumping difficulty across time-points.ResultsAll patients understood the instructions to and were able to self-administer the OLSTS test safely. OLSTS is a valid measure of quadriceps strength (gender-adjusted Spearman's ρ = 0.53, P = 0.02). Knee pain (ρ = 0.44, P = 0.046) and readiness to return-to-sport (ρ = 0.55, P = 0.02) were additional correlates. Greater OLSTS performance was associated with greater odds of better self-reported running and jumping function (interquartile-range ORs, 12.0 [95% CI: 3.6–45] and 18.5 [95% CI: 5–67], respectively).ConclusionOLSTS is a feasible and valid test of quadriceps strength, demonstrating predictive validity with self-reported running and jumping post-ACLR. OLSTS potentially allows independent tracking of ACLR rehabilitation progress at home – an increasingly urgent necessity in the face of a global pandemic.     

Retro-odontoid pseudotumor without atlantoaxial subluxation

A retro-odontoid pseudotumor (ROP) is commonly associated with atlantoaxial subluxation (AAS). Here, we report a patient with ROP but without AAS. The patient was a 72-year-old man who did not have a history of rheumatoid arthritis or trauma to the head and neck. The patient was admitted to our hospital with gait disturbance, progressive motor weakness in both upper extremities and sensory disturbance in all four extremities. MRI showed a retro-odontoid mass with severe compression of the cervical spinal cord. A CT scan showed spondylotic changes in C5, C6, and C7 and bilateral facet fusion between C3 and C4. Dynamic radiography showed no evidence of AAS; there was loss of mobility at C2–C7 and excessive mobility at C1. Intraoperative pathological examination revealed that the lesion was a pseudotumor; therefore, posterior C1–C2 fixation was performed. MRI performed 6 months after the operation revealed that the pseudotumor was markedly reduced. To the best of our knowledge, patients with ROP without AAS are uncommon.     

Microstructures and mechanical properties of silks of silkworm and honeybee

Natural silks as important biomaterials have wide applications in scaffolds for tissues, biocompatible coatings and drug delivery, etc. In this paper, we report on the microstructures and mechanical properties of honeybee and silkworm silks. The microstructures and mechanical properties of these natural silks are measured by environment scanning electron microscopy (ESEM), scanning probe microscopy (SPM), tensile tests, and nanoindentation. It is found that the honeybee silk appears as a single fiber with a circular cross-section and has a much finer and smoother texture than the silkworm silk. The honeybee silk exhibits a distinct linear and brittle elastic feature with an elastic modulus of 6.5 GPa and a breaking strain of 3.8%, whereas the silkworm silk possesses a nonlinear and hierarchical failure character with an initial elastic modulus of 8.9 GPa and a breaking strain of 15.7%. Moreover, the nanoindentation measurements show that the honeybee silk exhibits much less anisotropy than the silkworm silk. The ratio of the longitudinal modulus to the transverse modulus of the honeybee silk is 2.0, whereas that of the silkworm silk is 18.9. The different structural and mechanical properties of the honeybee and silkworm silks are likely a result of their specific biological functions.     

Relationship Between Osteopenia and Lumbar Intervertebral Disc Degeneration in Ovariectomized Rats

Ovariectomy (OVX) can cause bone loss in rats, but little is known about how it also induces lumbar intervertebral disc degeneration (LVD). This study investigated how estrogen deficiency affected intervertebral discs in OVX rats. Thirty 3-month-old female Sprague–Dawley rats were divided randomly into three equal groups. The baseline control group (BL) was killed at the beginning of the experiment. An ovariectomy was performed in 10 rats (OVX group) and another group of 10 rats was subjected to a sham surgery (Sham group). The OVX rats were untreated after the surgery to allow for the development of moderate osteopenia. Bone mineral density (BMD) measurement and bone histomorphometric analysis were applied to the segments of lumbar spines in all rats killed 6 months after surgery. The pathological changes of intervertebral discs were observed and the degree of LVD was scored by a histological scoring system. The BMD of the spines (L3–L5) in the OVX group decreased significantly compared with the Sham group. The bone volume indices in the OVX group were significantly lower, but the bone turnover rate parameters were significantly higher than those in the Sham group (P < 0.01). The histological scores for LVD in the OVX group were significantly higher than those in the Sham group (P < 0.01). There was a significant negative correlation between the BMD and Grade II discs in the OVX rats (P = 0.042). In conclusion, LVD occurs in the OVX rats and the degeneration of cartilage end plates may be a pathogenic factor in disc degeneration.No benefits in any form have been or will be received from a commercial party related directly or indirectly to the support of this article. No funds were received in support of this study.