Normal Weight Bearing Research Articles

GRAFTS COMPARISON BETWEEN QUADRICEPS TENDON AUTOGRAFT VS. ALLOGRAFT FOR ANTERIOR CRUCIATE LIGAMENT REVISIOON RECONSTRUCTION: A LITERATURE REVIEW

Introduction: Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopaedic surgeries performed on active people in the world. One of the most important surgical decisions is graft type for use in the reconstruction. Recently, the quadriceps tendon has gained popularity for use as a graft source for ACL reconstruction. The graft choice is broadly between an autograft or allograft. This review aims to understand the current concepts in graft comparison between quadriceps tendon autograft vs. allograft for anterior cruciate ligament revision reconstruction. Methods: This literature review study was reported following the preferred reporting items for systematic reviews and adhered to a structured review protocol. The author searched the PubMed, ScienceDirect, and British Medical Journal databases. The authors comparing selected publications reporting patient outcomes with all types of reviews or descriptions of ACL revision reconstruction and its graft being used or other related subjects. Published in English is included. The author then formulates a synthesis to support the previously determined research objectives. Results: ACL reconstruction with partial thickness soft tissue quadriceps tendon graft is a reliable option. Where there are differences in the failure rates of ACL reconstructions between allografts and autografts, these can mostly be explained by irradiated grafts. Giving sufficient radiation to achieve sterility will likely weaken grafts and make them more likely to fail; therefore, irradiating grafts is not recommended. The evidence shows no significant differences in clinical effectiveness between autografts and non-irradiated allografts. Failure rates with both grafts are now low. Discussion: The primary goals of rehabilitation after ACL reconstruction do not vary considerably based on graft type and emphasize: (1) restoration of the full range of motion, (2) normalization of quadriceps strength, (3) improvement of overall lower extremity muscle strength, and (4) re-training of movement patterns to return to pre-injury sports participation while decreasing injury risk. Achieving full motion and quadriceps strength contributes to a rapid return to normal weight bearing, gait, and activities of daily living. In the setting of revision ACL reconstruction, there are various considerations regarding graft choice due to tunnel size or position, previous usage of other grafts, and reconstructions in the other leg, which may mean that allografts would be preferred to autografts. The other population not covered sufficiently in the literature is the elite sprinting athlete, where autograft choices may be influenced by the effect of graft harvesting on their sport. However, in most cases, allograft ACL reconstruction with non-irradiated grafts is as safe but more expensive than autograft ACL reconstruction, which is preferred as it is more cost-effective. Conclusion: There is little difference in the results of ACL reconstruction with autografts or non-irradiated allografts, with any advantage being with autografts. The cost is higher with allografts. So if autografts are available, allografts are not cost-effective.

Outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning.

To report the outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning (FGNMP). Retrospective case series. A total of 15 client owned dogs and two cats with 57 metabone fractures. Description of FGNMP and reporting of the following data: signalment, pre- and postoperative radiographs, intramedullary pin diameter used, anesthesia, surgery and coaptation times, duration to normal weightbearing and bone union, postoperative care and complications. Median surgery time was 54 min (range: 26-99), median duration of coaptation was 14 days (range: 1-5 weeks), median time to normal weightbearing was 16 days (range: 2-45) and median time to bone union was 6 weeks (range: 4-12). All cases had at least 12 months of post-surgical follow-up with a median follow-up of 18 months (range: 12-70). No major complications occurred. Mild radiographic changes associated with subchondral bone sclerosis were noted on follow-up radiographs in 13/57 fractures. All cases returned to normal gait and full (15) or acceptable (2) function. In this study, FGNMP was an effective and safe technique for metabone fracture repair, requiring only short-term external coaptation in most patients. Time to bone union and return to normal function compared favorably to previously reported techniques. Fluoroscopically guided normograde metabone pinning provides an alternative technique for treatment of metabone fractures.

Turf Toe Injuries in the Athlete: an Updated Review of Treatment Options, Rehabilitation Protocols, and Return-to-Play Outcomes.

First metatarsophalangeal joint sprains or turf toe (TT) injuries occur secondary to forceful hyperextension of the great toe. TT injuries are common among athletes, especially those participating in football, soccer, basketball, dancing, and wrestling. This review summarizes the current treatment modalities, rehabilitation protocols, and return-to-play criteria, as well as performance outcomes of patients who have sustained TT injuries. Less than 2% of TT injuries require surgery, but those that do are typically grade III injuries with damage to the MTP joint, evidence of bony injury, or severe instability. Rehabilitation protocols following non-operative management consist of 3 phases lasting up to 10 weeks, whereas protocols following operative management consist of 4 phases lasting up 20 weeks. Athletes with low-grade injuries typically achieve their prior level of performance. However, among athletes with higher grade injuries, treated both non-operatively and operatively, about 70% are expected to maintain their level of performance. The treatment protocol, return-to-play criteria, and overall performance outcomes for TT injuries depend on the severity and classification of the initial sprain. For grade I injuries, players may return to play once they experience minimal to no pain with normal weightbearing, traditionally after 3-5 days. For grade II injuries, or partial tears, players typically lose 2-4 weeks of play and may need additional support with taping when returning to play. For grade III injuries, or complete disruption of the plantar plate, athletes lose 4-6 weeks or more depending upon treatment strategy.

Successful functional salvage of a hindfoot injury with isolated soft tissue reconstruction: a case report

Abstract Calcaneus has an important functional role in walking, running, gait and transferring 80% of total weight. Due to the paramount role of the calcaneus in function, there is a trend toward ‘below knee amputation’ for such heel injuries, associated with complete loss of calcaneus. Complex calcaneal defects represent a reconstructive challenge, due to few reported cases in the literatures, limited surgical options, and lack of long-term outcomes. We present a young patient regaining near normal function, weight bearing and independent walking after sustaining complex hindfoot defect that resulted in total loss of the calcaneus secondary to a landmine blast injury managed by soft tissue reconstruction only without skeletal reconstruction.

The effectiveness of oxytetracycline in the treatment of calves with contracted flexor tendons

PICO question
 In neonatal calves with contracted flexor tendons is the use of a 3 day course of oxytetracycline in conjunction with other treatments more effective in returning the hoof to normal full weight bearing on both the toe and heel compared to no oxytetracycline?
 
 Clinical bottom line
 Category of research question
 Treatment
 The number and type of study designs reviewed
 Three papers were critically reviewed. One randomised controlled study, one case series and one case study
 Strength of evidence
 Weak
 Outcomes reported
 Oxytetracycline as a treatment for contracted flexor tendons in calves was found to be slightly more effective in returning the hoof to normal weight bearing compared to no oxytetracycline. In contrast, oxytetracycline infusions for the treatment of contracted flexor tendons in calves do not have an influence on weight bearing and have no significant clinical effect
 Conclusion
 There was limited confidence that the estimated effect reported by the studies were close to the true effect, this is due to the studies having a number of limitations as well as the case series / study having limited evidentiary power. There is currently insufficient evidence from the literature to support or reject the use of oxytetracycline in the treatment of contracted flexor tendons in calves. Further studies, with higher strengths of evidence, are required to provide conclusive evidence
 
 How to apply this evidence in practice
 The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.
 Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.
 

Supracutaneous locking compression plating for the management of humerus fracture in a dog

A dog was presented to the University Veterinary Hospital, Kokkalai with a history of nonweight bearing lameness on left forelimb and was diagnosed as humerus fracture. Supracutaneous locking compression plating was carried out after open reduction under general anaesthesia. Periodic clinical and radiographic evaluations were conducted at two weeks interval for a period of six weeks until the plate removal. Physiological and haematological parameters were within the normal range. The serum alkaline phosphatase level was high at the time of presentation and decreased progressively. The dog returned to sound gait, normal weight bearing and satisfactory functional limb usage by sixth post operative week. The fracture healed with periosteal and endosteal callus. The implant was intact and patient acceptance was satisfactory throughout the observation period.

Effects of spaceflight on cancellous and cortical bone in proximal femur in growing rats

Mechanical loading of the skeleton during normal weight bearing plays an important role in bone accrual and turnover balance. We recently evaluated bone microarchitecture in the femoral head in 5.6-week-old male Sprague Dawley rats subjected to a 4-day spaceflight aboard STS-41. Compared to weight bearing ground controls, cancellous bone volume fraction was dramatically lower in animals subjected to microgravity. The effects of spaceflight on the rat skeleton are potentially influenced by factors such as age, duration of flight, strain and sex. To test the generalizability of our initial observation, we evaluated archived proximal femora from two additional spaceflight missions: a 10-day mission (STS-57) with 7.5-week-old male Fisher 344 rats, and a 14-day mission (STS-62) with 12-week-old ovariectomized (ovx) female Fisher 344 rats. Cancellous microarchitecture and cortical thickness were assessed using x-ray microtomography/microcomputed tomography. In male rats, cancellous bone volume fraction (bone volume/tissue volume) was lower in flight animals compared to flight controls, but differences were not significant compared to baseline. In ovx female rats, cancellous bone volume fraction was lower in flight animals compared to flight controls and baseline, indicating net bone loss. Cortical thickness did not differ among groups in either experiment. In summary, findings from three separate studies support the conclusion that spaceflight results in cancellous osteopenia in femoral head of growing rats.

Axial-Loaded MRI Using a SpineMAC Device to Show Narrowing of Dural Sac and Disc Height in Lumbar Spinal Stenosis

Background: A lumbosacral spinal compression device has been developed by the authors (SpineMAC) to simulate normal weight-bearing by axial-loading of the lumbar spine while the patient is in the supine position. Objective: To investigate the effect of axial loading using a SpineMAC device, on lumbar spine, spinal canal, and spine curvature, in subjects with suspected spinal stenosis. Materials and Methods: The present study was prospective cross-sectional study. Forty-five (21 males and 24 females) consecutive Thai adults underwent unloaded and axial-loaded supine magnetic resonance imaging (MRI) examinations of the lumbosacral spine. Radiographic parameters included cross-sectional area of disc (DA), cross-sectional area of dural sac (DCSA), disc height (DH), anterior to posterior distance of disc (DAP), L1-L3-L5 angle (LA), and lumbar lordosis (LL). Results: During the axial-loaded MRIs, the pathologic features of the lumbar spinal stenosis such as the disc bulging, nerve root compression, narrowing of the spinal canal, and the spinal neural foramina, were frequently observed in L4-L5 and L5-S1. Radiographic parameters differences of more than 5% between unloaded and axial-loaded supine MRIs were observed in DCSA and DH. Narrowing of the dural sac due to axial compression was observed at the L4-L5 level (8.1%), while loss of DH was found at both the L5-S1 (-7.9%) and the L4-L5 (-6.8%) levels. Axial compression only slightly affected the DA and DAP of the intervertebral discs with a difference of 5% or less. Furthermore, it rarely changed the spine curvature (LL and LA) of the subjects, with a difference of 2% or less. LL decreased during axial loading and may not correlate with the findings during normal standing position. Although the authors found greater DA and DAP values in male (p<0.001) and obese (p<0.05) subjects, changes of radiographic parameters with axial loading were otherwise not correlated with sex, age, or body mass index. Conclusion: An axial-loaded MRI, using a SpineMAC device, may be superior to conventional MRI when evaluating narrowing of the dural sac and disc height of patients. Keywords: Lumbar lordosis, Spinal stenosis, Axial loading, Weight bearing, Disc herniation, Low back pain

Should 15° of valgus coronal-plane deformity be the upper limit for a total ankle arthroplasty?

Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°. A matched cohort of patients similar for demographics and components used but differing in preoperative coronal-plane tibiotalar valgus deformity ≥ 15° (valgus, n = 50; 52% male, mean age 65.8 years (SD 10.3), mean body mass index (BMI) 29.4 (SD 5.2)) or < 15° (control, n = 50; 58% male, mean age 65.6 years (SD 9.8), mean BMI 28.7 (SD 4.2)), underwent TAA by one surgeon. Preoperative and postoperative radiographs, Ankle Osteoarthritis Scale (AOS) pain and disability and 36-item Short Form Health Survey (SF-36) version 2 scores were collected prospectively. Ancillary procedures, secondary procedures, and complications were recorded. At mean 5.1 years follow-up (SD 2.6) (valgus) and 6.6 years (SD 3.3) (controls), mean AOS scores decreased and SF-36 scores increased significantly in both groups. Improvements in scores were similar for both groups - AOS pain: valgus, mean 26.2 points (SD 24.2), controls, mean 22.3 points (SD 26.4); AOS disability: valgus, mean 41.2 points (SD 25.6); controls, mean 34.6 points (SD 24.3); and SF-36 PCS: valgus, mean 9.1 points (SD 14.1), controls, mean 7.4 points (SD 9.8). Valgus ankles underwent more ancillary procedures during TAA (40 (80%) vs 13 (26%)) and more secondary procedures postoperatively (18 (36%) vs 7 (14%)) than controls. Tibiotalar deformity improved significantly (p < 0.001) towards a normal weightbearing axis in valgus ankles. Three valgus and four control ankles required subsequent fusion, including two for deep infections (one in each group). Satisfactory mid-term results were achieved in patients with preoperative valgus malalignment ≥ 15°, but they required more adjunctive procedures during and after TAA. Valgus coronal-plane deformity ≥ 15° is not an absolute contraindication for TAA if associated deformities are addressed. Cite this article: Bone Joint J 2020;102-B(12):1689-1696.

Morphology of bony callus growth in healing of a sheep tibial osteotomy

Long bone fractures typically heal via formation of an external callus, which helps stabilise the bone fragments. Callus composition and morphology influence the mechanical environment, which in turn regulates the progression of healing. Therefore characterising callus development over time is crucial in understanding this mechanobiological regulation. Although bony callus is often assumed to grow towards the fracture from either side, this is not consistent with observations from large animal studies and clinical cases. Therefore, we sought to quantify the morphology of bony callus over time in a large animal model.Sheep tibiae were x-rayed weekly over eight weeks following an osteotomy (n=5), with fixation allowing up to 10% axial displacement under normal weight-bearing. After scaling radiographs by known landmarks and normalising greyscales, bony callus boundaries were defined by manual segmentation. The lateral callus area and coordinates of its centroid were calculated from each image.The external callus initially formed adjacent to the osteotomy site. Over the first four weeks, callus growth from its outer surfaces was characterised by its centre of area moving outwards and away from the osteotomy, on both proximal and distal fragments. Subsequent weeks showed consolidation and resorption from the outer surface of the callus.Our approach allowed bony callus development to be tracked in individuals throughout healing. Contrary to the view that periosteal bone formation originates distant from the fracture, our data showed bony callus adjacent to the defect from early stages, followed by approximately concentric growth. This discrepancy highlights the need for data specific to experimental conditions, and particularly early stages of healing, for evaluating theoretical models of mechanical regulation.

Massage during muscle unloading increases protein turnover in the massaged and non‐massaged, contralateral limb, but does not attenuate muscle atrophy

In the current issue of Acta Physiologica, Lawrence et al. [1] provide a rigorous investigation into the effects of mechanical massage therapy on skeletal muscle during normal weight bearing (WB) and unloading conditions. One week of hindlimb suspension (HS) in rats was used to determine if massage is an effective therapy to blunt disuse associated muscle loss.Massage therapy increased muscle protein turnover compared to HS control, though muscle atrophy still occurred following massage and muscle disuse. Interestingly, message therapy increased muscle protein turnover in the contralateral, non-messaged limb compared to HS control.

Massage as a mechanotherapy promotes skeletal muscle protein and ribosomal turnover but does not mitigate muscle atrophy during disuse in adult rats.

Interventions that decrease atrophy during disuse are desperately needed to maintain muscle mass. We recently found that massage as a mechanotherapy can improve muscle regrowth following disuse atrophy. Therefore, we aimed to determine if massage has similar anabolic effects when applied during normal weight bearing conditions (WB) or during atrophy induced by hindlimb suspension (HS) in adult rats. Adult (10months) male Fischer344-Brown Norway rats underwent either hindlimb suspension (HS, n=8) or normal WB (WB, n=8) for 7days. Massage was applied using cyclic compressive loading (CCL) in WB (WBM, n=9) or HS rats (HSM, n=9) and included four 30-minute bouts of CCL applied to gastrocnemius muscle every other day. Massage had no effect on any anabolic parameter measured under WB conditions (WBM). In contrast, massage during HS (HSM) stimulated protein turnover, but did not mitigate muscle atrophy. Atrophy from HS was caused by both lowered protein synthesis and higher degradation. HS and HSM had lowered total RNA compared with WB and this was the result of significantly higher ribosome degradation in HS that was attenuated in HSM, without differences in ribosomal biogenesis. Also, massage increased protein turnover in the non-massaged contralateral limb during HS. Finally, we determined that total RNA degradation primarily dictates loss of muscle ribosomal content during disuse atrophy. We conclude that massage is an effective mechanotherapy to impact protein turnover during muscle disuse in both the massaged and non-massaged contralateral muscle, but it does not attenuate the loss of muscle mass.

Weight-Bearing Physical Activity Influences the Effect of Vitamin D on Bone Turnover Markers in Patients with Intellectual Disability.

Individuals with intellectual disabilities (IDs) are at increased risk for low bone mass and fragility fractures, and those who are nonambulatory may be at even higher risk. Patients with IDs often are vitamin D deficient, but there is little information concerning how vitamin D treatment of patients with IDs affects markers of bone formation and resorption. We performed a retrospective analysis of 23 institutionalized individuals with IDs who were the subject of a performance improvement continuing medical education project designed to reduce risk for fracture by optimizing serum vitamin D levels. Patients were divided into those with normal weight-bearing (NWB) physical activity (15 patients: 14 men, 1 woman) and those with low weight-bearing (LWB) physical activity (8 patients: 7 men, 1 woman). All of the subjects received 50,000 IU of vitamin D3 weekly for 4 to 8 weeks, followed by a maintenance dose of 50,000 IU monthly for 3 to 6 months. Bone turnover markers (type 1 cross-linked C-telopeptide [CTX], type 1 N-terminal propeptide [P1NP], and parathyroid hormone [PTH]) and 25(OH)-vitamin D levels were measured before and after vitamin D supplementation. At baseline, there were no significant differences in the serum levels of 25OH-D, PTH, P1NP, or CTX between the two groups (NWB and LWB). Vitamin D levels were increased to a higher value in LWB subjects than in NWB subjects (61 ± 4.1 vs 48.4 ± 2.2 ng/mL, P < 0.001). Vitamin D treatment suppressed PTH (20.5% ± 14.3% vs 31.4% ± 7.7%, P = not significant) and P1NP (33.0% ± 6.2% vs 29.4% ± 6.9%, P = not significant) similarly in both groups. Although CTX levels declined by 26.4% ± 5.3% (P = 0.0002) in NWB individuals (as anticipated), vitamin D supplementation resulted in an unexpected 25.8% ± 8% increase (P = 0.01) in CTX in LWB individuals, suggesting osteoclast activation. Although high-dose vitamin D appeared to suppress osteoclast activity in NWB adults with IDs, the increase in serum CTX levels in those with LWB activity implies activation of osteoclasts that could exacerbate their unique low bone mass and increase fracture risk. The results support the use of a lower-dose vitamin D regimen in this patient group with LWB.

Comparative Stiffness of an Equine Distal Sesamoid Bone Fracture Model Stabilized with 3.5-mm versus 4.5-mm Cortical Bone Screws in Lag Fashion.

The aim of this study was to to determine the comparative stiffness following repair of an axial sagittal fracture model in equine distal sesamoid bones using either a single 3.5-mm or 4.5-mm cortical bone screw placed in lag fashion. The present study was an in vitro biomechanical study. The mean (±standard deviation) stiffness value for the 4.5-mm screw-bone construct (522.49 N/mm ± 168.21) was significantly greater than the 3.5-mm screw-bone construct (408.46 N/mm ± 131.13) (p = 0.047). This represents a 28% difference in mean stiffness. In vitro, the 4.5-mm screw-bone construct creates a stiffer repair of fractured distal sesamoid bones by a margin of 28%. The 4.5-mm cortical bone screw may better withstand forces imparted on the distal sesamoid bone sustained during anaesthetic recovery, normal weight bearing and athletic exercise, thereby minimizing the risk of implant failure.

Massage Protects against Disuse Atrophy in Young Adult Rats

Maintenance of skeletal muscle (SkM) mass is essential for maintaining mobility and metabolic health. SkM unloading or disuse, such as extended bed rest or limb immobilization, leads to rapid SkM wasting. Interventions to prevent disuse atrophy have had limited success. We recently found that applying massage, in the form of cyclic compressive loading (CCL), during the reloading period after hindlimb unloading, results in a greater increase in SkM protein synthesis (MPS) and SkM fiber cross‐sectional area (CSA) compared to reloading alone in 10 month old male rats. The purpose of the current investigation was to determine if CCL has similar anabolic effects when applied during normal weight bearing (WB versus WBM) as an anabolic stimulus, or during hindlimb suspension (HS versus HSM) to prevent muscle loss. We hypothesized that CCL applied during WB or HS would enhance (WBM) or protect against SkM fiber CSA loss (HSM), respectively, by increasing ribosome biogenesis and MPS. Adult (10 month) male F344/Brown Norway rats underwent either HS (n=8) or WB (n=8) for 7 days. In the treatment groups, CCL was applied directly to the gastrocnemius muscle at a load of 4.5 N and 0.5 Hz for 30 min. every other day for a total of 4 bouts during HSM (n=9) or WBM (n=9). WBM had no significant differences (NSD) in any anabolic parameters assessed compared to WB. CSA was significantly lower in HS vs WB (2373.5±267.6 vs 3796.7±80.2 mm2), with HSM significantly minimizing the loss compared to HS (2737.4±64.0 vs 2373.5±267.6 mm2). We used D2O and modeling for non‐steady state conditions to measure myofibrillar protein synthesis (Ksyn) and breakdown (Kdeg), and ribosomal biogenesis (rRNA Ksyn) and breakdown (rRNA Kdeg). HS and HSM had significant decreases in myofibrillar Ksyn vs WB (13.5±0.63 and 22.8±2.1 vs 35.5±2.3 mg/day), with HSM being significantly greater than HS. Myofibrillar Kdeg was significantly elevated in HS and HSM vs WB (.030±.001 and .030±.001 vs .018±.001 1/t), with NSD between HS and HSM. Further, in HSM only, the contralateral non‐massaged gastrocnemius also had significantly greater myofibrillar Ksyn and CSA (22.5±1.8 mg/day and 2713.5±96.5 mm2) vs HS. There were NSD in rRNA Ksyn between any group, which was despite a significant decrease in total RNA in HS and HSM vs WB (520.8±25.3 and 545.2±35.9 vs 600.5±42.0 ng/mg muscle), with NSD between HS and HSM. However, rRNA Kdeg was significantly elevated in HS and HSM vs WB (.045±.000 and .040±.000 vs .006±.000 1/t), with HSM being significantly reduced vs HS. In summary, massage in weight bearing rats did not affect any anabolic parameter assessed. In contrast, there were strong and significant effects of massage during HS (HSM) by minimizing the loss of CSA through enhancing myofibrillar protein synthesis and protecting against ribosomal breakdown vs HS alone. These findings support the highly translatable potential of CCL to protect against SkM loss during disuse by increasing MPS in either the massaged or contralateral non‐massaged limb.Support or Funding InformationThis research was supported by NIH grant R01AT009268 and R21AG042699.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A novel model to assess lamellar signaling relevant to preferential weight bearing in the horse

Supporting limb laminitis (SLL) is a devastating sequela to severe unilateral lameness in equine patients. The manifestation of SLL, which usually only affects one limb, is unpredictable and the etiology is unknown. A novel, non-painful preferential weight bearing model designed to mimic the effects of severe unilateral forelimb lameness was developed to assess lamellar signaling events in the supporting limb (SL). A custom v-shaped insert was attached to the shoe of one forelimb to prevent normal weight bearing and redistribute weight onto the SL. Testing of the insert using a custom scale platform built into the floor of stocks confirmed increased distribution of weight on the SL compared with the unloaded forelimb (UL) and the contralateral (CH) and ipsilateral (IH) hind limbs in six Standardbred horses. In a second part of the study, eight healthy Standardbred horses were fitted with the insert and tied with consistent monitoring and free access to hay and water for 48 h, after which the lamellae were harvested. Real-time qPCR was performed to assess lamellar mRNA concentrations of inflammatory genes and immunoblotting and immunofluorescence were performed to assess lamellar protein concentration and cellular localization of hypoxia-related proteins, respectively.Lamellar mRNA concentrations of inflammatory signaling proteins did not differ between SL and either CH or IH samples. HIF-1α concentrations were greater (P < 0.05) in the SL compared to the CH. This work establishes an experimental model to study preferential weight bearing and initial results suggest that lamellar hypoxia may occur in the SL.

Ankle Reconstruction in Fibular Hemimelia: New Approach.

Fibular hemimelia is a congenital disorder that is characterized by the absence of the fibula that could be either partial or complete. Successful management aims to restore normal weight bearing and normal limb length. The introduction of the Ilizarov method of limb lengthening has provided an attractive alternative to amputation. During lengthening, the tight posterolateral soft-tissue structures, the thick fibrous fibular band, and the shortened Achilles tendon become tighter and transfer a valgus force to the talus and calcaneus, further aggravating the deformity. We have developed a strategy to address this in patients with Paley type III fibular hemimelia via ankle reconstruction that provides posterolateral stability and buttressing of the ankle and hind foot by reconstructing the lateral buttress. This is achieved through excision of the fibrous fibular anlage, centralization of the ankle, restoring talocalcaneal coronal alignment, and reconstruction of the lateral malleolus by transplanting the cartilaginous remnant of the lateral malleolus or by crafting a bone block autograft taken from the iliac crest or tibia. A prospective non-randomized clinical trial included ten ankles in eight patients with fibular hemimelia Paley type III (two patients had bilateral deformity). The patients' ages ranged from 7 to 36months. After a follow-up ranging from 48 to 96months, a stable plantigrade foot was achieved in nine ankles; one ankle had residual equinus, five ankles had residual valgus heel, and eight ankles had complete range of motion of the ankle, whereas one patient lost 5° of dorsiflexion. One ankle had equinus deformity. To achieve satisfactory results, a stable plantigrade foot and ankle is necessary in patients with fibular hemimelia before attempting to equalize limb length discrepancy. It is important to reconstruct the ankle through an extra-articular soft tissue release, anlage resection, osteotomies, and restoring the abnormal talocalcaneal relationship before any attempt to equalize LLD.

Spaceflight-Relevant Challenges of Radiation and/or Reduced Weight Bearing Cause Arthritic Responses in Knee Articular Cartilage.

There is little known about the effect of both reduced weight bearing and exposure to radiation during spaceflight on the mechanically-sensitive cartilage lining the knee joint. In this study, we characterized cartilage damage in rat knees after periods of reduced weight bearing with/without exposure to solar-flare-relevant radiation, then cartilage recovery after return to weight bearing. Male Sprague Dawley rats (n = 120) were either hindlimb unloaded (HLU) via tail suspension or remained weight bearing in cages (GROUND). On day 5, half of the HLU and GROUND rats were 1 Gy total-body X-ray irradiated during HLU, and half were sham irradiated (SHAM), yielding 4 groups: GROUND-SHAM; GROUND-IR; HLU-SHAM; and HLU-IR. Hindlimbs were collected from half of each group of rats on day 13. The remaining rats were then removed from HLU or remained weight bearing, and hindlimbs from these rats were collected on day 62. On day 13, glycosaminoglycan (GAG) content in cartilage lining the tibial plateau and femoral condyles of HLU rats was lower than that of the GROUND animals. Likewise, on day 13, immunoreactivity of the collagen type II-degrading matrix metalloproteinase-13 (MMP-13) and of a resultant metalloproteinase-generated neoepitope VDIPEN was increased in all groups versus GROUND-SHAM. Clustering of chondrocytes indicating cartilage damage was present in all HLU and IR groups versus GROUND-SHAM on day 13. On day 62, after 49 days of reloading, the loss of GAG content was attenuated in the HLU-SHAM and HLU-IR groups, and the increased VDIPEN staining in all treatment groups was attenuated. However, the increased chondrocyte clustering remained in all treatment groups on day 62. MMP-13 activity also remained elevated in the GROUND-IR and HLU-IR groups. Increased T2 relaxation times, measured on day 62 using 7T MRI, were greater in GROUND-IR and HLU-IR knees, indicating persistent cartilage damage in the irradiated groups. Both HLU and total-body irradiation resulted in acute degenerative and pre-arthritic changes in the knee articular cartilage of rats. A return to normal weight bearing resulted in some recovery from cartilage degradation. However, radiation delivered as both a single challenge and when combined with HLU resulted in chronic cartilage damage. These findings suggest that radiation exposure during spaceflight leads to and/or impairs recovery of cartilage upon return to reloading, generating long-term joint problems for astronauts.

Nerve growth factor inhibition with tanezumab influences weight-bearing and subsequent cartilage damage in the rat medial meniscal tear model

ObjectiveTo investigate whether the effects of nerve growth factor (NGF) inhibition with tanezumab on rats with medial meniscal tear (MMT) effectively model rapidly progressive osteoarthritis (RPOA) observed in clinical trials.MethodsMale...

A Prospective Clinical and Morphological Study of Facet Joint Integrity following Implantation of Two Different Cervical Disc Replacements

Introduction The ideal patient for a disc replacement with a mechanical prosthesis, such as Discocerv of Scient̀X or a M6 of spinal kinetics with a soft core, is under 60 years of age with monosegmental, symptomatic degenerative disc disease without degeneration in the facet joints. Following implantation of prosthesis any changes in load through the facet joints appear as changes in bone mineral density at the operative and adjacent levels. A comparing study was designed to investigate whether facet joint sclerosis and degeneration occurs following the implantation of the two different disc types. Materials and Methods In this prospective study, suitability for disc replacement was determined by CT scan and clinical assessments. Patients were followed up 6 and 12 months postoperatively. X-ray and CT-controlled osteoabsorptiometry were used to assess any changes in bone mineral density following implantation of the two different disc models. A 3D reconstruction enabled visualization of the bone density distribution in the facet joints. Pain and function was assessed using standard outcome scores (visual analog scale [VAS] back pain score, Oswestry disability index [ODI], and short form-36 [SF-36]). Mobility was determined by flexion/extension X-rays. Results In total, 20 patients received disc replacement, 10 patients in each group. The postoperative location of the areas of maximum bone mineral density did not change compared with the preoperative condition. There was a reduction in subchondral mineralization density in the facet joints of the operated segments and, to a lesser degree, in the neighboring segments. The mean improvement in the VAS back pain score 6-months postoperatively was 60%. Function, as measured by ODI and SF-36 scores, had improved by up to 70% at the same postoperative time point. Improvements in pain and function scores were maintained 12 month postoperatively. On average, normal movement and weight bearing was observed 8 weeks postoperatively. Mobility increased by a mean of 8 degrees in the operated segment. There was no big difference between the two disc designs. Conclusion Facet joint sclerosis and degeneration did not occur following cervical disc replacement. There was no big change in the location of the areas of maximum density, indicating that mobility approached normal physiological levels. The reductions in subchondral mineralization density suggest normalization away from degenerative sclerosis in both disc types. This did not appear to be due to adoption of postoperative postures as normal movement and weight bearing was achieved. Further study is needed to assess these two different disc designs and the degree to which restoration of segmental mobility leads to the normalization of degenerative sclerosis.