The association between tibial torsion, knee flexion excursion and foot progression during gait in people with knee osteoarthritis: a cross-sectional study.

BACKGROUND: Lower limb malalignment is associated with gait kinematics, but there is limited information on the relationship between gait kinematics and tibial torsion in individuals with knee osteoarthritis (OA). This study aimed to investigate possible associations between tibial torsion and early stance kinematics during gait in people with mild and moderate medial knee OA. METHODS: Forty-seven participants (age: 62.1 ± 6.0 years; female/male: 37/10) diagnosed with medial knee OA were recruited from a regional hospital. Thirty of them had mild and seventeen had moderate knee OA. Lower limb alignment including tibial torsion and valgus/varus alignment were assessed by an EOS biplaner X-ray system with participants in weight-bearing position. Lower limb kinematics during gait was captured using the Vicon motion analysis system. The associations were estimated by partial Pearson correlation coefficient test. RESULTS: Our results indicated that external tibial torsion was related to early stance knee flexion excursion in participants with moderate knee OA (r = -0.58, p = 0.048), but not in participants with mild knee OA (r = 0.34, p = 0.102). External tibial torsion was associated with external foot progression angle (r = 0.48, p = 0.001), and knee varus/valgus alignment was associated with knee flexion excursion (r = -0.39, p = 0.010) in all participants. CONCLUSIONS: Both horizontal and frontal lower limb alignments were associated with knee flexion excursion at early stance of gait cycle in participants with medial knee OA. The distal rotational profile of lower limb would likely affect knee motion in sagittal plane. It implies that people with moderate knee OA could possibly benefit from correction of rotational alignment of lower limb.

Pain, balance, and mobility in people 1 year after total knee arthroplasty: a non-randomized cross-sectional pilot study contrasting posterior-stabilized and medial-pivot designs.

BACKGROUND: Total knee arthroplasty (TKA) is a common treatment for severe knee osteoarthritis. Medial-pivot TKA systems (MP-TKA) are theoretically better than posterior-stabilized TKA systems (PS-TKA) in improving static and dynamic balance of patients although it is difficult to objectively quantify these balance parameters in a clinical setting. Therefore, this pilot study aimed to evaluate the feasibility of using wearable devices in a clinical setting to examine whether people with MP-TKA have better postoperative outcomes than PS-TKA, and their balance control is more akin to age-matched asymptomatic controls. METHODS: The current cross-sectional pilot study recruited 57 participants with 2 different prosthesis designs (20 PS-TKA, 18 MP-TKA) and 19 asymptomatic controls. At 1-year post-TKA, pain, knee stiffness, and physical function were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Static balance, mobility, and gait stability of the participants were evaluated based on data collected from wearable motion sensors during the near tandem stance, timed-up-and-go, and 6-min walk tests. RESULTS: Compared to asymptomatic controls, both TKA groups reported significantly more pain and stiffness and demonstrated reduced functional mobility, increased stride-time-variability, and impaired balance. After Bonferroni adjustment, no significant differences in pain, balance, and mobility performance were observed between PS-TKA and MP-TKA participants 1 year after surgery. However, there was a trend for increased anteroposterior sway of the lumbar and head regions in the MP-TKA participants when undertaking the near tandem stance test. The wearable motion sensors were easy to use without any adverse effects. CONCLUSIONS: It is feasible to use wearable motion sensors in a clinical setting to compare balance and mobility performance of patients with different TKA prothesis designs. Since this was a pilot study and no definite conclusions could be drawn, future clinical trials should determine the impacts of different TKA prosthesis designs on post-operative outcomes over a longer follow-up period.

Hemodynamic stress shapes subchondral bone in osteoarthritis: An emerging hypothesis.

Osteoarthritis (OA) is no longer regarded as a simple wear-and-tear problem of articular cartilage. Instead, OA is a whole joint disorder involving both cartilaginous and non-cartilaginous tissues such as subchondral bone and synovium. Among them, subchondral bone undergoes constant remodeling in response to the changes of mechanical environment. Current understanding of subchondral bone disturbance in OA is limited to its link with an altered local mechanical loading as a result of ligament or meniscus injury. Very recently, hypertension, the most common vascular morbidity, has been emerged as an independent risk factor of OA. It might suggest a plausible role of systemic hemodynamic mechanical stress in subchondral bone remodeling and the pathogenesis of OA. However, their relationship remains not fully understood. Based on our preliminary clinical observation on the association of hemodynamic parameters with subchondral bone mass and microstructure in late-stage knee OA patients, we formulate a vascular etiology hypothesis of OA from a mechanobiology perspective. Noteworthily, hemodynamic stress associated with subchondral bone mineral density; yet compressive mechanical loading does not. Furthermore, hemodynamic parameters positively correlated with subchondral plate-like trabecular bone volume but negatively associated with rod-like trabecular bone volume. In contrast, compressive mechanical loading tends to increase both plate-like and rod-like trabecular bone volume. Taken together, it warrants further investigations into the distinct role of hemodynamic or compressive stress in shaping subchondral bone in the pathophysiology of OA. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This work provides a new insight, from the angle of biomechanics, into the emerging role of vascular pathologies, such as hypertension, in the pathogenesis of OA. It might open up a new avenue for the development of a mechanism-based discovery of novel diagnostics and therapeutics.

Exploring the relationship between pain intensity and knee moments in participants with medial knee osteoarthritis: a cross-sectional study.

BACKGROUND: High biomechanical loading is believed to be a risk factor to pain in people with knee osteoarthritis (OA), but controversial findings have been reported on the relationship between external knee adduction moment (KAM) and pain. A more comprehensive analysis considering other factor such as external knee flexion moment (KFM) could help better reveal this relationship. This study explored the relationship between external knee adduction moment and pain intensity in participants with knee osteoarthritis (OA) using an integrated path analysis model. METHODS: This was a cross-sectional study based on laboratory setting. Forty-seven participants with clinical and radiographic medial knee OA were analyzed for their external knee adduction moment (KAM) and knee flexion moment (KFM) during walking using a motion analysis system. Pain intensity was measured by visual analogue scale (VAS) and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score. Varus/valgus alignment was captured and quantified using a bi-planar X-ray system. Using a path analysis model, the relationships between pain intensity, KAM, KFM, OA radiographic severity, knee varus angle and walking speed were examined. RESULTS: The proposed path model met the goodness-of-fit criteria. Based on this model, KAM had a negative effect on VAS pain indirectly through the mediation of KFM. The model indicated KAM and KFM were negatively related to one another; and KFM was positively related to VAS. The KAM index, defined as (KAM/ (KAM + KFM)), was negatively related to VAS. CONCLUSIONS: Path analysis enabled the construction of a more integrated pathokinematic framework for people with knee OA. The KAM index which reflected the load sharing on the frontal and sagittal planes also revealed its relationship with pain. Re-distribution of mechanical loading from frontal to sagittal plane might be a strategy for pain avoidance associated with mechanical irritation.

Three-Dimensional Printing and Computer Navigation for Correction of Multiple Deformities in Osteogenesis Imperfecta: A Case Report.

CASE: A 44-year-old man with osteogenesis imperfecta presented with multiple debilitating musculoskeletal deformities. Bi-level osteotomies, assisted by 3-dimensional (3D)-printed patient-specific cutting guides, were performed to correct extraarticular valgus and procurvatum tibial deformities. Concomitant computer-navigated total knee arthroplasty was performed to restore neutral mechanical alignment. Postoperative x-ray showed good correction of deformities, and 1 year postoperatively, the patient is able to walk unaided with significant resolution of knee pain. CONCLUSION: 3D-printed osteotomy guides and computer navigation can be instrumental in procedures requiring a high degree of precision. With sufficient training, modern orthopaedic technologies can be implemented by surgeons themselves and combined to facilitate precise and personalized management of challenging conditions.

Acceptability and feasibility of a community-based strength, balance, and Tai Chi rehabilitation program in improving physical function and balance of patients after total knee arthroplasty: study protocol for a pilot randomized controlled trial.

BACKGROUND: The rate of falls in patients after total knee arthroplasty (TKA) is high and related to lower limb muscle weakness and poor balance control. However, since routine post-TKA rehabilitation is uncommon, it is paramount to explore alternative strategies to enhance balance and physical functioning in post-TKA patients. As Tai Chi is a proven strategy for improving balance in older people, the proposed study aims to determine the feasibility and acceptability of a 12-week community-based post-TKA multimodal Tai Chi program and to collect preliminary data with respect to the efficacy of such a program in improving balance and physical functioning in post-TKA patients as compared to usual postoperative care. METHODS: A single-blinded 2-arm pilot randomized controlled trial will recruit 52 community-dwelling post-TKA patients (aged > 60 years) in Hong Kong. In addition, 26 untreated asymptomatic controls will be recruited for comparison purposes. The TKA patients will be randomized into either a 12-week multimodal Tai Chi rehabilitation group or a postoperative usual care group (26 each). Participants will perform the outcome assessments at baseline, 6, 12, 24, and 52 weeks after TKA, while asymptomatic controls will have the same assessments at baseline, 12, and 52 weeks after baseline. The rate of recruitment, retention, and attrition, as well as adherence to the intervention, will be measured and used to determine the feasibility of the study and whether a full-scale effectiveness trial is warranted. Further, qualitative interviews will be conducted to explore the acceptability and possible barriers to the implementation of the intervention. Primary and secondary outcomes including both patient-reported surveys and performance-based tests will be compared within and between groups. DISCUSSION: The study will determine the feasibility and acceptability/potential efficacy of community-based rehabilitation for post-TKA patients and assess whether the intervention has the potential to be assessed in a future fully powered effectiveness trial. The findings will also be used to refine the study design and guide the conduction of a future definitive randomized controlled trial. TRIAL REGISTRATION: ClinicalTrials.gov NCT03615638. Registered on 30 May 2018. https://clinicaltrials.gov/ct2/show/NCT03565380.

Correcting severe flexion contracture with fusiform capsulectomy of posterior capsule during total knee arthroplasty.

PURPOSE: This study aimed to evaluate the safety and efficacy of fusiform capsulectomy of posterior capsule in correcting severe flexion contracture during total knee arthroplasty (TKA). METHODS: A retrospective analysis was performed in the patients who had preoperative severe flexion contracture (> 30 degrees) prior to TKA and received fusiform capsulectomy of posterior capsule during TKA between December 2013 and November 2018. Range of motion (ROM), knee functional score, forgotten joint score (FJS), post-operative complications, and radiographic results were collected and evaluated. RESULT: Twenty patients (32 knees) were enrolled in this study. The mean duration of follow-up was 27.19 ± 15.92 months. The flexion contracture improved from pre-operative 37.69 ± 11.79° to post-operative 5.78 ± 4.44° (p < 0.001), and ROM increased from pre-operative 63.50 ± 21.74° to post-operative 97.88 ± 13.20° (p < 0.001). KSS clinical score increased from pre-operative 32.94 ± 11.03 to post-operative 82.34 ± 10.73 (p < 0.001), and KSS function score increased from pre-operative 28.97 ± 18.43 to post-operative 68.75 ± 15.96 (p < 0.001). The post-operative FJS was 76.08 ± 2.14. There was no implant loosening, infection, obvious haematoma formation, resultant instability, neurovascular complications, or revision for any reasons in the cohort until the last follow-up. CONCLUSIONS: The technique of fusiform capsulectomy of posterior capsule to correct the severe flexion contracture during primary TKA is safe and effective and could provide good short-term results.

Intraoperative monitoring of the femoral and sciatic nerves in total hip arthroplasty with high-riding developmental dysplasia.

AIMS: This study aimed to explore whether intraoperative nerve monitoring can identify risk factors and reduce the incidence of nerve injury in patients with high-riding developmental dysplasia. PATIENTS AND METHODS: We conducted a historical controlled study of patients with unilateral Crowe IV developmental dysplasia of the hip (DDH). Between October 2016 and October 2017, intraoperative nerve monitoring of the femoral and sciatic nerves was applied in total hip arthroplasty (THA). A neuromonitoring technician was employed to monitor nerve function and inform the surgeon of ongoing changes in a timely manner. Patients who did not have intraoperative nerve monitoring between September 2015 and October 2016 were selected as the control group. All the surgeries were performed by one surgeon. Demographics and clinical data were analyzed. A total of 35 patients in the monitoring group (ten male, 25 female; mean age 37.1 years (20 to 46)) and 56 patients in the control group (13 male, 43 female; mean age 37.9 years (23 to 52)) were enrolled. The mean follow-up of all patients was 13.1 months (10 to 15). RESULTS: The two groups had no significant differences in preoperative data. In the monitoring group, ten nerve alerts occurred intraoperatively, and no neural complications were detected postoperatively. In the control group, six patients had neural complications. The rate of nerve injury was lower in the monitoring group than in the control group, but this did not achieve statistical significance. The degree of leg lengthening was significantly greater in the monitoring group than in the control group. In further analyses, patients who had previous hip surgery were more likely to have intraoperative nerve alerts and postoperative nerve injury. CONCLUSION: Nerve injury usually occurred during the processes of exposure and reduction. The use of intraoperative nerve monitoring showed a trend towards reduced nerve injury in THA for Crowe IV DDH patients. Hence, we recommend its routine use in patients undergoing leg lengthening, especially in those with previous hip surgery. Cite this article: Bone Joint J 2019;101-B:1438-1446.

Magnoflorine with hyaluronic acid gel promotes subchondral bone regeneration and attenuates cartilage degeneration in early osteoarthritis.

OBJECTIVE: To investigate efficacy of Chinese medicine magnoflorine combined with hyaluronic acid (HA)-gel in promoting subchondral bone (SCB) regeneration and attenuating cartilage degeneration in early osteoarthritis (OA). METHODS: MC3T3-E1 under magnoflorine treatment was assayed by XTT to determine cell viability. Cell proliferation was reflected through cell cycle. Osteoblast mineralization was stained by Alizarin Red. Standardized bone canal of 1 mm in diameter and 4 mm in depth was made on tibial medial plateau of 4-month-old Dunkin-Hartley spontaneous knee OA guinea pigs. Guinea pigs (n = 5/group) were treated once intra-bone canal injection of 2 µl HA-gel, 2 µl HA-gel+50 ng magnoflorine and null (Defect) respectively, except sham group. The left hind limbs were harvested for µCT scan and histopathological staining 2-month post-surgery. RESULTS: 25 µg/ml magnoflorine treatment significantly increased cell viability, S-phase and mineralization of MC3T3-E1 cells. In vivo, HA-gel + magnoflorine treatment significantly altered SCB microstructure; changes included increase in bone volume fraction (BV/TV), trabecular number (Tb.N), connectivity density (Conn.Dn), and decrease in degree of anisotropy (DA), which implied trabecular bone regeneration. Treatment also resulted in a decrease in modified Mankin's scores, and an increase in volume ratio of hyaline cartilage (HC)/calcified cartilage (CC) and fractal dimension (FD, roughness indicator of osteochondral conjunction), compared to Defect and HA groups. Furthermore, FD was positively associated with volume ratio of HC/CC and negatively associated with modified Mankin's scores. Finally, histological results showed that due to a faster regeneration of SCB with the HA-gel + magnoflorine treatment, the reduction of cartilage matrix and the decreased expression of chondrogenic signals were attenuated. CONCLUSION: Our study elucidated the potential benefits of HA-gel + magnoflorine in promoting SCB regeneration and revealed a protective effect of stimulating recovery of the SCB integrity on attenuating cartilage degradation to prevent OA progression.

High-Frequency Ultrasound Imaging of Tidemark In Vitro in Advanced Knee Osteoarthritis.

High-frequency ultrasound imaging has been widely adopted for assessment of the degenerative changes of articular cartilage in osteoarthritis (OA). Yet, there are few reports on investigating its capability to evaluate subchondral bone. Here, we employed high-frequency ultrasound imaging (25 MHz) to examine in vitro the tidemark in cylindrical osteochondral disks (n = 33) harvested from advanced OA knees of humans. We found good correspondence in morphology observed by ultrasound imaging and micro-computed tomography. Ultrasound roughness index (URI) of tidemark was derived from the raw radiofrequency signals to compare with bone quality factors, including bone volume fraction (BV/TV) and bone mineral density (BMD) measured by micro-computed tomography, using the Spearman correlation (ρ). URI of the tidemark was negatively associated with the subchondral plate BV/TV (ρ = -0.73, p <0.001), BMD (ρ = -0.40, p = 0.020), as well as the underneath trabecular bone BV/TV (ρ = -0.39, p = 0.025) and BMD (ρ = -0.43, p = 0.012). In conclusion, this preliminary study demonstrated that morphology measured by high-frequency ultrasound imaging could reflect the quality of the subchondral bone. High-frequency ultrasound is a promising imaging tool to evaluate the changes of the subchondral bone in addition to those of the overlying cartilage in OA.

Restoration of Humeral Bone Stock Two Years After Internal Fixation of a Periprosthetic Fracture with a Loose Stem: A Report of Two Cases.

CASE: We describe 2 patients who sustained a periprosthetic humeral fracture with a loosened long-stemmed Coonrad-Morrey total elbow prosthesis. As noted in the literature, the success rate for a major revision with use of strut grafts is around 70%; therefore, both cases were managed without revision of the prosthesis. A submuscular locking plate was placed following typical fracture fixation principles. Screws that interfered with the humeral stem and the distal flange stabilized both the distal fragment and the humeral stem. CONCLUSION: At 2 years postoperatively, both fractures had healed, with increased endosteal bone stock. In each case, the prosthesis was successfully salvaged, and radiographic reconstitution of the implant-bone interface was noted after 2 years.

Is subchondral bone cyst formation in non-load-bearing region of osteoarthritic knee a vascular problem?

Subchondral bone cyst is common in the progressive knee osteoarthritis yet its underlying mechanism remains unclear. In addition to the existing theories such as synovial fluid influx and mechanical contusion, we identified the potential link between vascular pathology and osteoarthritic bone pathologies including cystic lesion formation, particularly in the non-load-bearing region. This new hypothesis for SBC formation in non-load-bearing region for knee, which cannot be explained by the existing theories, will provide us a new angle to understand the pathomechanism and pathophysiology of subchondral bone disturbance in osteoarthritis in addition to the classical biomechanical overloading theories. It might guide us to develop a novel diagnostic and therapeutic approach to treat progressive osteoarthritis via targeting vascular pathology.

Does Barbed Suture Lower Cost and Improve Outcome in Total Knee Arthroplasty? A Randomized Controlled Trial.

BACKGROUND: Wound closure is key to prevent infection, facilitate immediate rehabilitation, and improve efficiency of total knee arthroplasty (TKA). Continuous knotless suturing with barbed suture can potentially save time and distribute tension more evenly. However, its role in TKA in terms of cost-effectiveness and wound complications is not clear. This study aims at comparing barbed and traditional sutures' wound closure time and cost in primary TKA. METHODS: One hundred nine knees were randomized into either barbed or traditional group. Synthetic absorbable sutures (Vicryl, Ethicon Inc) and bidirectional barbed sutures (Stratafix, Ethicon Inc) were used. Arthrotomy and subcutaneous wound closure time, wound complications, and rehabilitation parameters in terms of range of motion and Knee Society Score were compared. Patients were followed up to 3 months. RESULTS: Traditional sutures had significantly more positive leak tests (10 vs 2, P value <.05) and wound complications (11 vs 2, P value <.05). No differences in range of motion and Knee Society Score were noted. Arthrotomy and subcutaneous closure time were significantly shorter with barbed sutures (arthrotomy 325 seconds vs 491 seconds; subcutaneous 306 seconds vs 381 seconds, P value <.05). Concerning cost of suture material and operation time, barbed suture on average saved USD 48.7 per TKA in our local institute. CONCLUSION: Bidirectional barbed suture improves the cost-effectiveness of TKA through reducing wound closure time and wound complications.

Effect of tibial drill-guide angle on the mechanical environment at bone tunnel aperture after anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: The tibial drill-guide angle in anterior cruciate ligament (ACL) reconstruction influences the tunnel placement and graft-tunnel force, and is potentially associated with post-operative tunnel widening. This study aimed to examine the effect of the drill-guide angle on the stress redistribution at the tibial tunnel aperture after anatomic single-bundle ACL reconstruction. METHODS: A validated finite element model of human knee joint was used. The tibial tunnel with drill-guide angle ranging from 30° to 75° was investigated. The post-operative stress redistribution in tibia under the compressive, valgus, rotational and complex loadings was analysed. RESULTS: Compressive loading played a leading role on the stress redistribution at intra-articular tibial tunnel aperture. After ACL reconstruction, stress concentration occurred in the anterior and posterior regions of tunnel aperture while stress reduction occurred in the lateral and posteromedial regions under the compressive loading. Stress redistribution was partially alleviated by using the drill-guide angle ranging from 55° to 65°. CONCLUSIONS: The present study quantified the effect of bone tunnel drill-guide angle on the post-operative stress redistribution. This phenomenon potentially contributed to tunnel widening. A tunnel drill-guide angle ranging from 55° to 65° was proposed based on the biomechanical rationale. It could serve as a helpful surgical guide for ACL reconstruction.

Anterior dislocation after total hip replacement - effects of pelvic rotation and femoral head size.

We investigated the effects of pelvic rotation and femoral head diameter on the anterior stability of the hip joint after total hip replacement. Computer navigation and cadaveric bone were used to simulate the range of motion after total hip replacement. The hip was put at 0 degrees of flexion and it was gradually externally rotated until the hip dislocated. The degree of external rotation when the hip was dislocated was recorded. The test was repeated with the hip at +10, -10, -20, -30, -40 and -50 degrees of flexion. The acetabular component was positioned with abduction of 45 degrees and anteversion at 20 degrees. There was a significant difference amongst each group of pelvic rotation from 0 to -50 degrees in the degree of external rotation when the hip was dislocated. The degree became insignificant when pelvic rotation was increased from 0 to 10 degrees. From -10 to -50 degree of pelvic rotation, 36mm head had significant better stability compared with 32mm and 28mm femoral heads. The presence of significant pelvic sagittal malrotation can increase the risk of anterior dislocation. A larger femoral head is more stable than smaller heads. When pelvic sagittal malrotation is not present, there is no difference in stability between large and small femoral heads.

The accuracy of sizing of the femoral component in total knee replacement.

PURPOSE: Femoral sizing in total knee replacement is important. Either undersizing or oversizing may result in deleterious effects to the clinical outcome after the surgery. There has been no study on the precision and accuracy of femoral sizing and the effect of measurement at different landmarks over the distal femur. This study assesses the intra-observer and inter-observer error of femoral sizing and identifies the effect of the placement site of the anterior referencing tool on femoral sizing. METHODS: Five investigators with different clinical experience measured the femoral size of 10 cadaveric specimens twice using three anterior referencing tool. The measurement of the femoral size was repeated at nine designated points on the anterior cortex of the cadaveric femora. RESULTS: Excellent intraobserver and interobserver agreements were obtained using the three anterior referencing tools. When the size on which the majority agreed was regarded as the actual size of the specimen, measurement at the nine designated points on the anterior cortex showed a deviation from the actual size from 6.2 to 46.2 %. Placing the femoral sizer stylus at the middle and 2 cm above the proximal margin of the anterior femoral condyle yielded the highest precision and accuracy. CONCLUSION: Regardless of the experience of the surgeons, measurement of the femoral size using the three anterior referencing tools is very accurate. Placing the stylus of the femoral sizer at the middle and 2 cm above the proximal margin of the anterior femoral condyle best reflects the actual size of the femur. LEVEL OF EVIDENCE: Experimental study.

Deterioration of stress distribution due to tunnel creation in single-bundle and double-bundle anterior cruciate ligament reconstructions.

Bone tunnel enlargement is a common effect associated with knee laxity after anterior cruciate ligament(ACL) reconstruction. Nevertheless, its exact pathomechanism remains controversial. One of the possible reasons could be bone remodeling due to tunnel creation, which changes the stress environment in the joint. The present study aims to characterize the deteriorated stress distribution on the articular surface, which is due to tunnel creation after single-bundle or double-bundle ACL reconstruction. The stress distributions in the knee following ACL reconstruction under the compression, rotation, and valgus torques were calculated using a validated three-dimensional finite element(FE) model. The results indicate that, (a) under compression,von Mises stress is decreased at lateral and posteromedial regions of single/anteromedial (AM) tunnel, whereas it is increased at anterior region of single/AM tunnel in tibial subchondral bone; (b) the concentration of tensile stress is transferred from the articular surface to the location of graft fixation, and tensile stress in subchondral plate is decreased after ACL reconstruction; (c) severe stress concentration occurs between AM and posterolateral tunnels following the double-bundle reconstruction, which may contribute to the tunnel communication after surgery. In summary, the present study affirms that the deterioration of stress distribution occurs near the articular surface, which may cause the collapse of the tunnel wall, and lead to tunnel enlargement.The present study provides an insight into the effect of tunnel creation on articular stress deterioration after single-bundle or double-bundle ACL reconstruction. These findings provide knowledge on the effect of tunnel enlargement after ACL reconstruction in the long term.

Multimodal periarticular injection vs continuous femoral nerve block after total knee arthroplasty: a prospective, crossover, randomized clinical trial.

This study compares the efficacy of pain control using continuous femoral nerve block (FNB) and multimodal periarticular soft tissue injection. This is a randomized, crossover, clinical trial. Sixteen patients having bilateral osteoarthritis of the knee scheduled for staged total knee arthroplasty were randomized to receive either FNB (0.2% ropivacaine), via indwelling catheter for 72 hours, or multimodal periarticular soft tissue injection in the first stage. In the second stage, they received the opposite treatment. The primary outcome measure was morphine consumption by patient-controlled analgesia in the first 72 hours postoperatively. Cumulative morphine consumption as well as rest pain and motion pain in the first 72 hours was comparable between the 2 groups. The functional outcomes did not differ significantly. We conclude that multimodal periarticular soft tissue injection provides comparable analgesia to continuous FNB after total knee arthroplasty.