Effect of exercise on knee joint contact forces in people following medial partial meniscectomy: A secondary analysis of a randomised controlled trial

BackgroundArthroscopic partial meniscectomy may cause knee osteoarthritis, which may be related to altered joint loading. Previous research has failed to demonstrate that exercise can reduce medial compartment knee loads following meniscectomy but has not considered muscular loading in their estimates.Research questionWhat is the effect of exercise compared to no intervention on peak medial tibiofemoral joint contact force during walking using an electromyogram-driven neuromusculoskeletal model, following medial arthroscopic partial meniscectomy?MethodsThis is a secondary analysis of a randomized controlled trial (RCT). 41 participants aged between 30–50 years with medial arthroscopic partial meniscectomy within the past 3–12 months, were randomly allocated to either a 12-week, home-based, physiotherapist-guided exercise program or to no exercise (control group). Three-dimensional lower-body motion, ground reaction forces, and surface electromyograms from eight lower-limb muscles were acquired during self-selected normal- and fast-paced walking at baseline and follow-up. An electromyogram-driven neuromusculoskeletal model estimated medial compartment contact forces (body weight). Linear regression models evaluated between-group differences (mean difference (95% CI)).ResultsThere were no significant between-group differences in the change (follow-up minus baseline) in first peak medial contact force during self-selected normal- or fast-paced walking (0.07 (−0.08 to 0.23), P = 0.34 and 0.01 (−0.19 to 0.22), P = 0.89 respectively). No significant between-group difference was found for change in second peak medial contact force during normal- or fast-paced walking (0.09 (−0.09 to 0.28), P = 0.31 and 0.02 (−0.17 to 0.22), P = 0.81 respectively). At the individual level, variability was observed for changes in first (range −26.2% to +31.7%) and second (range −46.5% to +59.9%) peak tibiofemoral contact force.SignificanceThis is the first study to apply electromyogram-driven neuromusculoskeletal modelling to an exercise intervention in a RCT. While our results suggest that a 12-week exercise program does not alter peak medial knee loads after meniscectomy, within-participant variability suggests individual-specific muscle activation patterns that warrant further investigation.     

Inertial sensors identified asymmetries in shank angular velocity at different gait speeds in individuals with anterior cruciate ligament reconstruction

BackgroundInertial sensors can detect between-limb asymmetries in shank angular velocity (SAV) during loading response of walking in individuals with ACL reconstruction (ACLR), which may be indicative of abnormal knee joint loading. However, it is unknown whether these SAV asymmetries would exist up to 6 months post-ACLR and how they differ from SAV asymmetries in uninjured healthy subjects.Research questionTo investigate whether patients with ACLR show significant and meaningful between-limb SAV asymmetries during walking and walking fast at 4 and 6 months post-surgery and to determine whether limb asymmetries are related across gait tasks and time.MethodsFifteen individuals with ACLR participated in this prospective study. Testing occurred in clinical settings. Participants were instructed to walk and walk fast while wearing one inertial sensor on each shank. The average of sagittal plane SAV peaks during loading response of gait was calculated bilaterally. The smallest meaningful between-limb difference for SAV was calculated from uninjured healthy subjects (n = 16) to define the limit of meaningful SAV asymmetries in patients with ACLR.ResultsAt 4 and 6 months post-ACLR, the involved limb had significantly smaller peak SAV during walking (P < .01, d = 0.69−0.85) and walking fast (P < .005, d = 1.03−1.07) compared to the uninvolved limb. A significant main effect of gait task on SAV asymmetries was found (P = .006, η_p² = 0.451). Further, patients with ACLR exhibited meaningful SAV asymmetries at both time points for both gait speeds. Limb SAV asymmetries correlated between gait tasks and across time (r = 0.760−0.860, P < .001).SignificanceIndividuals with ACLR presented with significant and meaningful SAV asymmetries during walking and walking fast at 4 and 6 months post-surgery. Greater limb SAV asymmetries persisted across gait tasks and time, with greater asymmetry was observed at a faster walking speed. Thus, inertial sensors are feasible to be used in clinical settings to identify SAV asymmetry during gait post-ACLR.     

Tibiofemoral contact mechanics after serial medial meniscectomies in the human cadaveric knee

BACKGROUND: There is no consensus regarding the extent of meniscectomy leading to deleterious effects on tibiofemoral contact mechanics. HYPOTHESIS: The meniscus aids in optimizing tibiofemoral contact mechanics, increasing contact area, and decreasing contact stress. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen human cadaveric knees each underwent 15 separate testing conditions-5 serial 20-mm posterior medial meniscectomy conditions (intact, 50% radial width, 75% radial width, segmental, and total meniscectomy) at 3 flexion angles (0 degrees , 30 degrees , and 60 degrees )-under an 1800-N axial load. Tekscan sensors were used to measure total force and medial force, contact area, mean contact stress, and peak contact stress. RESULTS: All posterior medial meniscectomy conditions resulted in significantly decreased contact areas and increased mean and peak contact stresses compared with the intact state (P < .05). The changes in contact mechanics after segmental and total posterior medial meniscectomies were not statistically different (P > .05). Incremental changes in contact area and mean contact stress increased as more peripheral portions of the medial meniscus were removed, whereas peak contact stresses exhibited similar incremental changes throughout all meniscectomy conditions. CONCLUSIONS: The meniscus is a crucial load-bearing structure, optimizing contact area and minimizing contact stress. Loss of hoop tension (ie, segmental meniscectomy) is equivalent to total meniscectomy in load-bearing terms. The peripheral portion of the medial meniscus provides a greater contribution to increasing contact areas and decreasing mean contact stresses than does the central portion, whereas peak contact stresses increase proportionally to the amount of meniscus removed. CLINICAL RELEVANCE: Because the degree of meniscectomy leading to clinically significant outcomes is unknown, a prudent strategy is to preserve the greatest amount of meniscus possible.     

Healing results of meniscal tears left in situ during anterior cruciate ligament reconstruction: a review of clinical studies

The presence of peripheral meniscal tears is common at the time of anterior cruciate ligament (ACL) reconstruction. Techniques to preserve the maximum amount of meniscal tissue include “non operative” management (tear left alone, without repair or removal), meniscus repair, partial meniscectomy. There is a lack of consensus guidelines about the management of peripheral stable meniscal tears. When to remove, let alone or repair? We performed an evidence-based review of the outcomes of stable meniscal tears left in situ during ACL surgery, in order to assess the effectiveness of this popular procedure. Clinical and anatomical results (arthrography or second look arthroscopy) were analyzed. Our literature search yielded ten relevant studies (9 level IV, 1 level III). The mean time of follow-up was 16 months. Pain or mechanical symptoms related to the medial tibiofemoral joint were reported in 0–66% of cases. Subsequent medial meniscectomy or repair were performed in 0–33% of cases. Pain or mechanical symptoms related to the lateral tibiofemoral joint were reported in 0–18% cases. Subsequent lateral meniscectomy or repair were performed in 0–22% cases. A complete healing occurred in 50–61% cases for the medial meniscus and in 55–74% cases for the lateral meniscus. No definite conclusion can be made with regard to these results. The conservative approach is more effective for lateral menisci. The rate of bad results for the medial meniscus remains high when a conservative treatment is used. For the medial meniscus, repair of stable peripheral tears may be always indicated to decrease the risk of postoperative pain or subsequent meniscectomy.     

Gait and plantar sensation changes following massage and textured insole application in patients after anterior cruciate ligament reconstruction

BackgroundGait impairments following anterior cruciate ligament reconstruction (ACLR) may contribute to reinjury or future osteoarthritis development. Recently, plantar cutaneous sensation deficits have been reported post-ACLR. These sensory deficits may influence gait and represent a mechanism through which to improve gait.Research questionCan established sensory interventions change sensation and gait in patients after ACLR and compared to healthy adults?MethodsTwenty-two adults (n = 11 post-ACLR, age:20.5 ± 1.9years, body mass index[BMI]:24.5 ± 3.6 kg/m²; n = 11 healthy, age:20.7 ± 1.4years, BMI:23.3 ± 2.7 kg/m²) completed two sessions separated by 48 h. Gait and plantar cutaneous sensation were assessed pre- and post-intervention (massage or textured insoles). Gait analysis was completed using 3D motion capture at 1.4 m/s ± 5% and standard inverse dynamics analysis. Plantar cutaneous sensation was assessed using Semmes Weinstein Monofilaments with a 4−2-1 stepping algorithm at the plantar aspect of the first metatarsal head, base of the fifth metatarsal, and lateral and medial malleoli. Plantar massage was a 5-minute massage to both feet. Textured insoles (coarse grit sandpaper) were worn while walking. Biomechanical data were assessed via mixed-models, repeated measures ANOVAs and 90 % confidence intervals. Wilcoxon Signed Rank tests and Mann-Whitney U tests evaluated plantar cutaneous sensation within and between groups, respectively.ResultsKnee adduction moment was lower in the ACLR versus the contralateral limb pre-massage. The vGRF was lower during the first half of stance but greater during the second half of stance in the ACLR versus the control group post-massage. Massage improved ACLR limb sensation over the first metatarsal head (P = 0.042) and medial malleolus (P = 0.027). Textured insole application improved ACLR limb sensation over the first (P = 0.043) and fifth (P = 0.027) metatarsals and medial malleolus (P = 0.028).SignificancePlantar massage and textured insoles improved plantar cutaneous sensation in the ACLR limb. Neither intervention influenced gait. Improving plantar sensation may be beneficial for patients after ACLR; however, sensory interventions to improve gait are necessary.     

Does varus alignment increase after medial meniscectomy?

Purpose

In patients who underwent arthroscopic meniscectomy for medial meniscus tears, the authors wished to ascertain (1) whether varus alignment in the lower extremity would increase after an operation and (2) if so, what the related factors would be.

Methods

Among 181 patients from 20 to 60 years of age who underwent arthroscopic medial meniscectomy for medial meniscus tears between 2002 and 2005, 56 patients followed for a minimum period of 5 years were enroled for this study. Alignment in the lower extremity was measured preoperatively and again at the last follow-up. Change in varus alignment (the difference between preoperative alignment and alignment at the last follow-up) was analyzed in relation to sex, age, body mass index (BMI), resection amount (partial vs. total), preoperative alignment, and follow-up duration, using multiple linear regression analysis.

Results

Varus deformity increased by 1.7° ± 1.5° from a preoperative mean of 2.4° ± 2.4° to a mean of 4.1° ± 3.0° at the last follow-up, which was statistically significant (p = 0.000). From multiple linear regression analysis, only the resection amount (partial meniscectomy or total meniscectomy) was found to be significantly related to the change in varus alignment (p = 0.002). Other factors including sex, age, BMI, preoperative alignment, presence of cartilage injury and follow-up duration were not significantly related to the change in varus alignment after the operation.

Conclusions

Arthroscopic meniscectomy performed in patients with medial meniscus tears aggravated varus alignment in the lower extremity at the last follow-up. In addition, the increase in varus deformity was significantly higher among patients with total meniscectomy than among those with partial meniscectomy.

Level of evidence

Retrospective comparative study, Level III.     

Trunk,pelvis and lower limb walking biomechanics are similarly altered in those with femoroacetabular impingement syndrome regardless of cam morphology size

BackgroundStudies of walking in those with femoroacetabular impingement syndrome have found altered pelvis and hip biomechanics. But a whole body, time-contiuous, assessment of biomechanical parameters has not been reported. Additionally, larger cam morphology has been associated with more pain, faster progression to end-stage osteoarthritis and increased cartilage damage but differences in walking biomechanics between large compared to small cam morphologies have not been assessed.Research questionAre trunk, pelvis and lower limb biomechanics different between healthy pain-free controls and individuals with FAI syndrome and are those biomechanics different between those with larger, compared to smaller, cam morphologies?MethodsTwenty four pain-free controls were compared against 41 participants with FAI syndrome who were stratified into two groups according to their maximum alpha angle. Participants underwent three-dimensional motion capture during walking. Trunk, pelvis, and lower limb biomechanics were compared between groups using statistical parametric mapping corrected for walking speed and pain.ResultsCompared to pain-free controls, participants with FAI syndrome walked with more trunk anterior tilt (mean difference 7.6°, p < 0.001) as well as less pelvic rise (3°, p < 0.001), hip abduction (-4.6°, p < 0.05) and external rotation (-6.5°, p < 0.05). They also had lower hip flexion (-0.06Nm⋅kg⁻¹, p < 0.05), abduction (-0.07Nm⋅kg⁻¹, p < 0.05) and ankle plantarflexion moments (-0.19Nm⋅kg⁻¹, p < 0.001). These biomechanical differences occurred throughout the gait cycle. There were no differences in walking biomechanics according to cam morphology size.SignificanceResults do not support the hypothesis that larger cam morphology is associated with larger differences in walking biomechanics but did demonstrate general differences in trunk, pelvis and lower limb biomechanics between those with FAI sydrome and pain-free controls. Altered external biomechanics are likely the result of complex sensory-motor strategy resulting from pain inhibition or impingement avoidance. Future studies should examine internal loading in those with FAI sydnrome.     

Isolated ACL versus multiple knee ligament injury: associations with patient characteristics,cartilage status,and meniscal tears identified during ACL reconstruction

Objectives: The objectives of this study were to determine (1) if patients undergoing reconstruction of an isolated anterior cruciate ligament (ACL) tear had different characteristics (age, gender, body mass index [BMI]) than patients undergoing ACL reconstruction (ACLR) with multiple knee ligament (MKL) tears and (2) whether there was a difference in prevalence of articular cartilage injury and meniscus tears between these two groups.

Methods: Patients undergoing primary ACLR between February 2005 and June 2013 were identified through an ACLR registry. Patients were grouped by whether they had an isolated ACL tear or an ACL tear associated with another knee ligament tear. The study cohort was analyzed to identify differences in patient characteristics and cartilage/meniscus injury patterns between the groups.

Results: Of the 21,377 ACLR cases enrolled in the registry during the study period, 2.5% (n = 549) had MKL tears. The MKL group had more males (73.2% vs. 62.8%, p < 0.001) than the isolated ACL group. The MKL group also had a higher percentage of patients with a BMI greater than 30 (31.1% vs. 22.7%, p = 0.0002). When adjusting for these variables, any articular cartilage injury was equal in the two groups (OR = 1.01, CI 0.82–1.25, p = 0.922), while medial femoral condyle injury was less common in the MKL group (OR = 0.73, CI = 0.56–0.07, p = 0.28). The likelihood of any meniscus tear was lower in the MKL group (OR = 0.56, CI = 0.47–0.67, p < 0.001) as was the likelihood of medial meniscus tears (OR = 0.53, CI = 0.44–0.65, p < 0.001).

Conclusions: When comparing patients with MKL tears versus isolated ACL tears at ACLR, there was a higher percentage of males and patients with BMI over 30 in the MKL group. Medial femoral condyle articular cartilage injury, any meniscus tear, and medial meniscus tears were less common in patients with MKL injury compared to patients with isolated ACL tears.     

Neuromuscular and biomechanical landing performance subsequent to ipsilateral semitendinosus and gracilis autograft anterior cruciate ligament reconstruction

The hamstrings musculature is a vital component of an intricate dynamic knee joint restraint mechanism. However, there is evidence based on research studies suggesting potential deficits to this complex mechanism due to donor site morbidity resulting from harvest of the ipsilateral semitendinosus and gracilis autograft (ISGA) for anterior cruciate ligament reconstruction (ACLR). The purpose of this retrospective research study was to investigate the effects of ISGA ACLR on neuromuscular and biomechanical performance during a single-leg vertical drop landing (VDL), a functional task and associated mechanism of anterior cruciate ligament disruption during physical activity. Fourteen physically active participants 22.5 ± 4.1 years of age and 21.4 ± 10.7 months post ISGA ACLR underwent bilateral neuromuscular, biomechanical and isokinetic strength and endurance evaluations matched to 14 control participants by sex, age, height and mass. Kinetic and kinematic data was obtained with 3-D motion analyses utilizing inverse dynamics while performing single-leg VDLs from a height of 30 cm. Integrated surface electromyography (SEMG) assessments of the quadriceps, hamstrings and gastrocnemius musculature were also conducted. Additionally, knee joint flexion strength (60° s⁻¹) and endurance (240° s⁻¹) measurements were tested via isokinetic dynamometry. No significant differences existed in hip and net summated extensor moments within or between groups. The ISGA ACLR participants recorded significantly decreased peak vertical ground reaction force (VGRF) landing upon the involved lower extremity compared to uninvolved (P = 0.028) and matched (P < 0.0001) controls. Participants having undergone ISGA ACLR also displayed greater peak hip joint flexion angles landing upon the involved lower extremity compared to uninvolved (P = 0.020) and matched (P = 0.026) controls at initial ground contact. The ISGA ACLR group furthermore exhibited increased peak hip joint flexion angles landing upon the involved lower extremity compared to uninvolved (P = 0.019) and matched (P = 0.007) controls at peak VGRF. Moreover, ISGA ALCR participants demonstrated greater peak knee (P = 0.005) and ankle (P = 0.017) joint flexion angles when landing upon the involved lower extremity compared to the matched control at peak VGRF. The ISGA ACLR group produced significantly greater reactive muscle activation of the vastus medialis (P = 0.013), vastus lateralis (P = 0.008) and medial hamstrings (P = 0.024) in the involved lower extremity compared to the matched control. The ISGA ACLR participants also exhibited greater preparatory (P = 0.033) and reactive (P = 0.022) co-contraction muscle activity of the quadriceps and hamstrings landing upon the involved lower extremity compared to the matched control. In addition, the ISGA ACLR group produced significantly less preparatory (P = 0.005) and reactive (P = 0.010) muscle activation of the gastrocnemius in the involved lower extremity compared to the uninvolved control. No significant differences were present in hamstrings muscular strength and endurance. Harvest of the ISGA for purposes of ACLR does not appear to result in significant neuromuscular, biomechanical or strength and endurance deficiencies due to donor site morbidity. However, it is evident that this specific population exhibits unique neuromuscular and biomechanical adaptations aimed to stabilize the knee previously subjected to ACL trauma and safeguard the ISGA ACLR joint. Co-contraction of quadriceps and hamstrings as well as inhibition of gastrocnemius muscle activation may serve to moderate excessive loads exposed to the intra-articular ISGA during single-leg VDLs. Furthermore, greater muscle activation of the hamstrings in conjunction with increased peak hip, knee and ankle joint flexion angles may assist in enhancing acceptance of VGRF transferred through the kinetic chain following single-leg VDLs.     

The relationship between patellofemoral and tibiofemoral morphology and gait biomechanics following arthroscopic partial medial meniscectomy

Purpose

To examine the relationship between tibiofemoral and patellofemoral joint articular cartilage and subchondral bone in the medial and gait biomechanics following partial medial meniscectomy.

Methods

For this cross-sectional study, 122 patients aged 30–55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy, underwent gait analysis and MRI on the operated knee once for each sub-cohort of 3 months, 2 years, or 4 years post-surgery. Cartilage volume, cartilage defects, and bone size were assessed from the MRI using validated methods. The 1st peak in the knee adduction moment, knee adduction moment impulse, 1st peak in the knee flexion moment, knee extension range of motion, and the heel strike transient from the vertical ground reaction force trace were identified from the gait data.

Results

Increased knee stance phase range of motion was associated with decreased patella cartilage volume (B = ?17.9 (95 % CI ?35.4, ?0.4) p = 0.045) while knee adduction moment impulse was associated with increased medial tibial plateau area (B = 7.7 (95 % CI 0.9, 13.3) p = 0.025). A number of other variables approached significance.

Conclusions

Knee joint biomechanics exhibited by persons who had undergone arthroscopic partial meniscectomy gait may go some way to explaining the morphological degeneration observed at the patellofemoral and tibiofemoral compartments of the knee as patients progress from surgery.

Level of evidence

III.     

Tibial rotation outcomes following hamstring lengthening as part of single event multilevel surgery in children with cerebral palsy

BackgroundHamstring lengthening remains the most common surgical procedure in the treatment of crouch gait for children with cerebral palsy (CP). While sagittal plane knee kinematics have been shown to improve post-surgery, the effects on transverse plane kinematics have not been reported. Given the differing actions of the medial and lateral hamstring muscles there is potential for change in tibial rotation post hamstring lengthening.Research questionWhat is the effect of medial only versus combined medial and lateral hamstring lengthening on tibial rotation during gait in children with CP?MethodsA retrospective analysis of children with a diagnosis of CP who underwent a hamstring lengthening procedure. These children were divided into 2 groups: G1 (n = 18) had isolated medial hamstring lengthening while G2 (n = 30) had combined medial and lateral hamstring lengthening. A matched non-surgical control group (n = 15) was also included. Kinematic data were analysed pre and post-operatively. Pre-operative to post-operative outcomes for G1 and G2, a comparison at baseline for both groups and the difference in outcomes between the groups were analysed. Baseline to follow-up outcomes for the control group were also analysed.ResultsExternal tibial rotation increased significantly within groups (G1: −10°, p < 0.01; G2: −11°, p < 0.001, control: −7.7, p < 0.01), with no significant difference in the change between the intervention groups. Foot progression angles became more external in both intervention groups (G1: −15°, p < 0.001; G2: −15°, p < 0.0001) and did not change in the control group.SignificanceResults demonstrated similar increases in external tibial rotation, regardless of whether an isolated medial or combined medial and lateral surgery was performed. The control group demonstrated a similar change in external tibial rotation suggesting that hamstring lengthening surgery does not contribute to increased external tibial rotation in children with CP compared to what would be expected due to natural progression.     

Restoring tibiofemoral alignment during ACL reconstruction results in better knee biomechanics

Purpose

Anterior cruciate ligament (ACL) reconstruction (ACLR) aims to restore normal knee joint function, stability and biomechanics and in the long term avoid joint degeneration. The purpose of this study is to present the anatomic single bundle (SB) ACLR that emphasizes intraoperative correction of tibiofemoral subluxation that occurs after ACL injury. It was hypothesized that this technique leads to optimal outcomes and better restoration of pathological tibiofemoral joint movement that results from ACL deficiency (ACLD).

Methods

Thirteen men with unilateral ACLD were prospectively evaluated before and at a mean follow-up of 14.9 (SD?=?1.8) months after anatomic SB ACLR with bone patellar tendon bone autograft. The anatomic ACLR replicated the native ACL attachment site anatomy and graft orientation. Emphasis was placed on intraoperative correction of tibiofemoral subluxation by reducing anterior tibial translation (ATT) and internal tibial rotation. Function was measured with IKDC, Lysholm and the Tegner activity scale, ATT was measured with the KT-1000 arthrometer and tibial rotation (TR) kinematics were measured with 3Dmotion analysis during a high-demand pivoting task.

Results

The results showed significantly higher TR of the ACL-deficient knee when compared to the intact knee prior to surgery (12.2° ± 3.7° and 10.7° ± 2.6° respectively, P?=?0.014). Postoperatively, the ACLR knee showed significantly lower TR as compared to the ACL-deficient knee (9.6°±3.1°, P?=?0.001) but no difference as compared to the control knee (n.s.). All functional scores were significantly improved and ATT was restored within normal values (P?<?0.001).

Conclusions

Intraoperative correction of tibiofemoral subluxation that results after ACL injury is an important step during anatomic SB ACLR. The intraoperative correction of tibiofemoral subluxation along with the replication of native ACL anatomy results in restoration of rotational kinematics of ACLD patients to normal levels that are comparable to the control knee. These results indicate that the reestablishment of tibiofemoral alignment during ACLR may be an important step that facilitates normal knee kinematics postoperatively.

Level of evidence

Level II, prospective cohort study.

     

Is there a dose-response of medial wedge insoles on lower limb biomechanics in people with pronated feet during walking and running?

BackgroundAlthough the effects of medial wedge insoles on lower limb biomechanics have been investigated, information about the effects of different magnitudes of medial posting is still lacking.Research questionWhat are the dose-response effects of medial wedge insoles with postings varying between 0 °, 3 °, 6 °, and 9 ° of inclination on the lower limb biomechanics during walking and running in individuals with pronated feet?MethodsSixteen participants with an FPI ≥ 6 were recruited. Four arch-supported insole conditions with varying degrees of medial heel wedge were tested (0°, 3°, 6°, and 9°). A 3D motion analysis system with force plates was used to obtain the kinetics and kinematics of walking and running at self-selected speeds. To compare the ankle, knee, and hip angles and moments among conditions, a time series analysis was performed using Statistical Parametric Mapping (SPM).ResultsA reduction in ankle eversion angle was observed during walking for all insoles. For running, the 6° and 9° insoles decreased the ankle eversion angle during early stance and increased this angle during the propulsive phase. A decrease in ankle eversion moment was observed in walking and running for 6° and 9° insoles. An increase in knee adduction moment occurred in walking and running for all insoles. For hip, the 6° and 9° insoles showed, during walking, a decrease in hip adduction angle and an increase in hip adduction and external rotation moments. For most variables, statistical differences were found for a greater period across the stance phase as the medial wedge increased, except for ankle eversion moment and hip external rotation moment during walking.SignificanceThe biomechanical effects over the time series for many of the parameters increased with the addition of insole inclination, showing a dose-response effect of medial wedge insoles on the lower limb biomechanics during walking and running in adults with excessive foot pronation.     

Cost effectiveness of meniscal allograft for torn discoid lateral meniscus in young women

Objective: A discoid meniscus is more prone to tears than a normal meniscus. Patients with a torn discoid lateral meniscus are at increased risk for early onset osteoarthritis requiring total knee arthroplasty (TKA). Optimal management for this condition is controversial given the up-front cost difference between the two treatment options: the more expensive meniscal allograft transplantation compared with standard partial meniscectomy. We hypothesize that meniscal allograft transplantation following excision of a torn discoid lateral meniscus is more cost-effective compared with partial meniscectomy alone because allografts will extend the time to TKA.

Methods: A decision analytic Markov model was created to compare the cost effectiveness of two treatments for symptomatic, torn discoid lateral meniscus: meniscal allograft and partial meniscectomy. Probability estimates and event rates were derived from the scientific literature, and costs and benefits were discounted by 3%. One-way sensitivity analyses were performed to test model robustness.

Results: Over 25 years, the partial meniscectomy strategy cost $10,430, whereas meniscal allograft cost on average $4040 more, at $14,470. Partial meniscectomy postponed TKA an average of 12.5 years, compared with 17.30 years for meniscal allograft, an increase of 4.8 years. Allograft cost $842 per-year-gained in time to TKA.

Conclusion: Meniscal allografts have been shown to reduce pain and improve function in patients with discoid lateral meniscus tears. Though more costly, meniscal allografts may be more effective than partial meniscectomy in delaying TKA in this model. Additional future long term clinical studies will provide more insight into optimal surgical options.     

Tibiofemoral contact mechanics following posterior root of medial meniscus tear, repair, meniscectomy, and allograft transplantation

Purpose

The purposes of this study were to evaluate the effect on tibiofemoral contact mechanics of repair of the posterior root of the medial meniscus and the effect of meniscal allograft transplantation (MAT) with medial collateral ligament (MCL) release at different flexion angles.

Methods

Ten fresh-frozen human cadaveric knees (five pairs) were used. A digital pressure sensor was inserted by capsulotomy, and experiments were performed serially under the following six conditions, that is, with an intact medial meniscus (normal controls), with a root tear, after root repair, after total meniscectomy, after MAT, and after MAT plus MCL release. During each experiment, knees were positioned at 0°, 30°, 60°, and 90° of flexion, and peak pressure (kPa) and contact area (cm²) were measured.

Results

At 0° of flexion, contact pressure did not differ among the six experimental settings. However, at 30° and 60° of flexion, contact pressure differed significantly between root tear and root repair specimens (p = 0.04 and 0.03, respectively), and between total meniscectomy and MAT specimens (p = 0.02 and 0.03, respectively). On the other hand, mean contact pressures were different between normal (476.7 ± 473.1 and 573.3 ± 479.1 kPa) and root repair (575.7 ± 357.8 and 598.6 ± 415.8), and between normal and MAT (635.7 ± 437.4 and 674.3 ± 533.2). At 0°, 30°, 60°, and 90° of flexion, contact areas differed significantly between normal and total meniscectomy specimens (p = 0.02, 0.01, 0.02, and 0.02, respectively), and between MAT and total meniscectomy specimens (p = 0.03, 0.02, 0.02, and 0.03, respectively). Contact areas differed significantly between root tear and root repair specimens at 60° of flexion (p = 0.04), and between normal control and root repair specimens at 60° and 90° of flexion (p = 0.03 and 0.04, respectively). The effects of MAT plus MCL release on contact mechanics were not different from the effects of MAT alone (n.s.).

Conclusions

Both meniscal root repair and transplantation of meniscus improved contact mechanics, but it did not appear that repair of the meniscal root or transplantation of meniscus restores the biomechanical function back to normal level. The MAT plus MCL release was similar to those after MAT alone. Therefore, it is better to preserve meniscus and MCL release could be done during the MAT.     

关节镜下半月板部分切除术治疗膝关节半月板损伤的临床研究

目的探讨膝关节半月板损伤经关节镜下半月板部分切除术的治疗效果。方法回顾性分析新乡医学院第一附属医院骨科2013年8月—2016年8月收治的103例膝关节半月板损伤患者的临床资料,根据治疗方案将患者分为半月板成形术组(32例):男性19例,女性13例;致伤原因:道路交通伤19例,摔伤8例,高处坠落伤5例;非手术组(33例):男性20例,女性13例;致伤原因:道路交通伤18例,摔伤10例,高处坠落伤5例;半月板部分切除术组(38例):男性22例,女性16例;致伤原因:道路交通伤23例,摔伤9例,高处坠落伤6例。比较3组治疗前、治疗6个月、2年后的膝关节活动度、疼痛程度以及膝关节功能。结果半月板部分切除术组、半月板成形术组优良率均高于非手术组,且半月板部分切除术组高于半月板成形术组(P<0.05)。3组治疗6个月、2年后膝关节功能评分、膝关节活动度呈先升高后降低趋势(P<0.05);半月板成形术组、半月板部分切除术组治疗6个月、2年后膝关节功能评分、膝关节活动度均高于非手术组,且半月板部分切除术组高于半月板成形术组(P<0.05)。3组患者治疗6个月、2年后VAS评分呈先降低后升高趋势(P<0.05);半月板成形术组、半月板部分切除术组治疗6个月、2年后VAS评分均低于非手术组,且半月板部分切除术组低于半月板成形术组(P<0.05)。结论膝关节半月板损伤经关节镜下半月板部分切除术治疗,疗效确切,可有效改善患者膝关节活动度、膝关节功能,减轻机体疼痛感,具有临床应用价值。     

Effects of varus knee alignment on gait biomechanics and lower limb muscle activity in boys: A cross sectional study

BackgroundThere is evidence that frontal plane lower limb malalignment (e.g., genu varus) is a risk factor for knee osteoarthritis development. However, only scarce information is available on gait biomechanics and muscle activity in boys with genu varus.Research questionTo examine the effects of knee varus alignment on lower limb kinematics, kinetics and muscular activity during walking at self-selected speed in boys with genu varus versus healthy age-matched controls.MethodsThirty-six boys were enrolled in this study and divided into a group of boys with genu varus (n = 18; age: 11.66 ± 1.64 years) and healthy controls (n = 18; age: 11.44 ± 1.78 years). Three-dimensional kinematics, ground reaction forces, loading rates, impulses and free moments of both limbs were recorded during five walking trials at self-selected speed. Surface electromyography was recorded for rectus femoris and vastus lateralis/medialis muscles.ResultsNo significant between-group differences were found for gait speed. Participants in the genu varus group versus controls showed larger peak knee flexion (p = 0.030; d = 0.77), peak knee adduction (p < 0.001; d = 1.63), and peak ankle eversion angles (p < 0.001; d = 2.06). Significantly higher peak ground reaction forces were found at heel contact (vertical [p = 0.002; d = 1.16] and posterior [p < 0.001; d = 1.63] components) and at push off (vertical [p = 0.010; d = 0.93] and anterior [p < 0.001; d = 1.34] components) for genu varus versus controls. Peak medial ground reaction force (p = 0.032; d = 0.76), vertical loading rate (p < 0.001; d = 1.52), anterior-posterior impulse (p = 0.011; d = 0.92), and peak negative free moment (p = 0.030; d = 0.77) were significantly higher in genu varus. Finally, time to reach peak forces was significantly shorter in genu varus boys compared with healthy controls (p < 0.01; d = 0.73–1.60). The genu varus group showed higher activities in vastus lateralis (p < 0.001; d = 1.82) and vastus medialis (p = 0.013; d = 0.90) during the loading phase of walking.SignificanceOur study revealed genu varus specific gait characteristics and muscle activities. Greater knee adduction angle in genu varus boys may increase the load on the medial compartment of the knee joint. The observed characteristics in lower limb biomechanics and muscle activity could play a role in the early development of knee osteoarthritis in genu varus boys.     

Articular cartilage status 2 years after arthroscopic ACL reconstruction in patients with or without concomitant meniscal surgery: evaluation with 3.0T MR imaging

Purpose

To assess articular cartilage changes in the knee joint as detected on 3.0T MR imaging after 2-year follow-up in patients who underwent arthroscopic anterior cruciate ligament reconstruction (ACLR) with or without concomitant meniscal surgery.

Methods

A total of twenty-nine patients (mean age 30.3 ± 10 years), who underwent arthroscopic ACLR, received clinical and imaging follow-up at an average of 27.8 ± 4.8 months after surgery. Our patients were divided into two subgroups: eighteen patients with additional meniscal injuries at the time of arthroscopic ACLR who underwent meniscal surgery and eleven patients with intact menisci. The cartilage status of all knees at the time of arthroscopic ACLR was recorded. All patients underwent an MRI scan preoperatively and at follow-up with the same imaging protocol. Cartilage status of all knee compartments was evaluated at the time of follow-up by MR imaging and the ICRS classification.

Results

Deterioration of the cartilage status was found at all knee compartments of our study group, with respect to the number of cartilage defects. The cartilage of the lateral femoral condyle (LFC) was most severely affected, followed by patellar and medial femoral condyle (MFC) cartilage. A statistically significant relation was found between surgery of the medial meniscus and the development of new cartilage defects in LFC (p = 0.01) and MFC (p = 0.03) after adjusting for the site of meniscal surgery. The cartilage of LFC and the status of the medial meniscus were also found to be significantly related (p = 0.04). Partial meniscectomy was found to be associated with an increased incidence of new cartilage defects when compared to either meniscal repair or absence of meniscal surgery, although it was not statistically significant.

Conclusion

Development of new cartilage lesions was evident after 2-year follow-up in patients with arthroscopic ACLR as detected by MR imaging. There was a multicompartmental pattern of cartilage involvement, and the lateral compartment was most severely affected. Partial meniscectomy at the time of arthroscopic ACLR could be suggested as an additional risk factor for the progression of chondral lesions.

Level of evidence

Prospective comparative study, Level II.

     

Immediate effects of foot orthoses on gait biomechanics in individuals with persistent patellofemoral pain

BackgroundThe efficacy of foot orthoses in reducing patellofemoral pain (PFP) is well documented; however, the mechanisms by which foot orthoses modulate pain and function are poorly understood.Research questionThis within-subject study investigated the immediate effects of foot orthoses on lower limb kinematics and angular impulses during level walking and stair ambulation in individuals with persistent PFP.MethodsForty-two participants with persistent PFP (≥3 months duration) underwent quantitative gait analysis during level walking, stair ascent and stair descent while using: (i) standard running sandals (control); and (ii) standard running sandals fitted with prefabricated foot orthoses. Hip, knee, and ankle joint kinematics and angular impulses were calculated and statistically analyzed using paired t-tests (p < 0.05).ResultsRelative to the control condition, foot orthoses use was associated with small but significant decreases in maximum ankle inversion angles during walking (mean difference [95% confidence interval]: −1.00° [−1.48 to −0.53]), stair ascent (−1.06° [−1.66 to −0.45]) and stair decent (−0.94° [−1.40 to −0.49]). Foot orthoses were also associated with decreased ankle eversion impulse during walking (−9.8Nms/kg [−12.7 to −6.8]), and decreased ankle dorsiflexion and eversion impulse during stair ascent (−67.6Nms/kg [−100.7 to −34.6] and −17.5Nms/kg [−23.6 to −11.4], respectively) and descent (−50.4Nms/kg [−77.2 to −23.6] and −11.6Nms/kg [−15.6 to −7.5], respectively). Ankle internal rotation impulse decreased when participants ascended stairs with foot orthoses (−3.3Nms/kg [−5.4 to −1.3]). Limited changes were observed at the knee and hip.SignificanceIn individuals with persistent PFP, small immediate changes in kinematics and angular impulses – primarily at the ankle – were observed when foot orthoses were worn during walking or stair ambulation. The clinical implications of these small changes, as well as the longer-term effects of foot orthoses on lower limb biomechanics, are yet to be determined.     

Alterations in medial-lateral postural control after anterior cruciate ligament reconstruction during stair use

BackgroundDynamic postural control during everyday tasks is poorly understood in people following anterior cruciate ligament reconstruction (ACLR). Understanding dynamic postural control can provide insight into potentially modifiable impairments in people following ACLR who are at increased risk for second ACL injury and/or knee osteoarthritis.Research questionDetermine whether measures indicative of dynamic postural control differ between individuals with and without ACLR during stair ascent and descent. Methods: Seventeen individuals with ACLR (>1 yr post-surgery) and 16 age and sex-matched healthy controls participated. Centre of pressure (COP) measures included: i) COP excursion, ii) COP velocity, and iii) dynamic time-toboundary (TTB). Mixed linear models were used to compare COP measures for the ACLR leg, non-ACLR leg, and healthy controls during stair ascent and stair descent.ResultsThere were no statistically significant differences observed during stair ascent (all p > 0.05). Several statistical differences were found during stair descent for individual with ACLR, but not between those with ACLR and healthy controls. The ACLR leg had higher medial-lateral COP excursion (mean difference 1.06 cm, [95 %CI 0.08–2.06 cm], p = 0.036; effect size = 0.38) compared to the non-ACLR leg during stair descent. In addition, the ACLR leg had a lower medial-lateral TTB (mean difference −13 ms [95 %CI −38 to 2 ms], p = 0.005; effect size = 0.49) and medial-lateral TTB normalized to stance time (mean difference −5.8 % [95 %CI −10.3 to 1.3 %], p = 0.012; effect size = 0.80) compared to the non-ACLR leg during stair descent. No statistical differences were observed for anterior-posterior measures during stair descent (all p > 0.05). Significance: Taken together, findings indicate that there are small to large differences in medial-lateral postural control in the ACLR leg compared to the non-ACLR leg during stair descent. Further work is required to understand clinical implication of these novel observations.