Non-weight-bearing Group Research Articles

Local administration of bone morphogenetic protein-2 and bisphosphonate during non-weight-bearing treatment of ischemic osteonecrosis of the femoral head: an experimental investigation in immature pigs.

Non-weight-bearing decreases the femoral head deformity but increases bone resorption without increasing bone formation in an experimental animal model of Legg-Calvé-Perthes disease. We sought to determine if local administration of bone morphogenetic protein (BMP)-2 with or without bisphosphonate can increase the bone formation during the non-weight-bearing treatment in the large animal model of Legg-Calvé-Perthes disease. Eighteen piglets were surgically induced with femoral head ischemia. Immediately following the surgery, all animals received an above-the-knee amputation to enforce local non-weight-bearing (NWB). One to two weeks later, six animals received local BMP-2 to the necrotic head (BMP group), six received local BMP-2 and ibandronate (BMP+IB group), and the remaining six received no treatment (NWB group). All animals were killed at eight weeks after the induction of ischemia. Radiographic, microcomputed tomography (micro-CT), and histomorphometric assessments were performed. Radiographic assessment showed that the femoral heads in the NWB, BMP, and BMP+IB groups had a decrease of 20%, 14%, and 10%, respectively, in their mean epiphyseal quotient in comparison with the normal control group. Micro-CT analyses showed significantly higher femoral head bone volume in the BMP+IB group than in the BMP group (p = 0.02) and the NWB group (p < 0.001). BMP+IB and BMP groups had a significantly higher trabecular number (p < 0.01) and lower trabecular separation (p < 0.02) than the NWB group. In addition, the osteoclast number per bone surface was significantly lower in the BMP+IB group compared with the NWB group. Calcein labeling showed significantly higher bone formation in the BMP and BMP+IB groups than in the NWB group (p < 0.05). Heterotopic ossification was found in the capsule of four hips in the BMP+IB group but not in the BMP group. Administration of BMP-2 with bisphosphonate best decreased bone resorption and increased new bone formation during non-weight-bearing treatment of ischemic osteonecrosis in a pig model, but heterotopic ossification is a concern. This preclinical study provides new evidence that BMP-2 with bisphosphonate can effectively prevent the extreme bone loss associated with the non-weight-bearing treatment and increase new bone formation in the femoral head in this animal model of ischemic osteonecrosis.

The effect of non-weight bearing group-exercising on females with non-specific chronic low back pain: A randomized single blind controlled pilot study

The aim of this study was to investigate the effect of active non-weight-bearing (NWB) group exercising on women with non specific chronic low back pain (NSCLBP). Forty females with NSCLBP were assigned in a randomized control longitudinal single blinded pilot study. 20 of them were assigned to a NWB bi-weekly group exercise class and 20 females were included in the control group. The exercises involved the entire lumbo-pelvic spine aimed at improving lumbar mobility/flexibility and stability. Pain intensity (VAS), back specific disability (Rolland Morris questionnaire-RMQ), and lumbar flexion and extension ranges of motion measurements were taken prior to intervention (t(0)), immediately following 4 weeks of intervention (t(1)) and 8 weeks later (t(fu)). Reliability trials were conducted on 10 females. Non-parametric tests were used for statistical significance (p < 0.05). The following significant changes in outcome measures were indicated at t(1) compared with t(0) and control group (p < 0.001): an increase in lumbar flexion and extension (mean difference = 9.26◦ (+54%) for flexion and 5.95◦ for extension(+98%)); reduction in VAS score (mean difference = 2.32 (+58%)) and RMQ score (mean difference = 4.9 (−34%)). All changes remained significant at t(fu). At t(0), lumbar flexion was correlated with extension (r = 0.547) and VAS (r = −0.581),whereas the RMQ score correlated with VAS score (r = 0.599) and negatively with lumbar extension (r = −0.665). At t(1),lumbar flexion correlated with extension (r = 0.664) and negatively with RMQ score (r = −0.54). At t(fu), changes in VAS score were negatively correlated with changes in lumbar flexion (r = −0.522), while changes in lumbar flexion correlated with extension (r = 0.58). A functional program of NWB group exercising improves functional, painful status, lumbar flexion and extension ranges of motion in women suffering from NSCLBP.

Weight-Bearing Versus Nonweight-Bearing Exercise for Persons With Diabetes and Peripheral Neuropathy: A Randomized Controlled Trial

ObjectiveTo determine the effects of weight-bearing (WB) versus nonweight-bearing (NWB) exercise for persons with diabetes mellitus (DM) and peripheral neuropathy (PN). DesignRandomized controlled trial with evaluations at baseline and after intervention. SettingUniversity-based physical therapy research clinic. ParticipantsParticipants with DM and PN (N=29) (mean age ± SD, 64.5±12.5y; mean body mass index [kg/m2] ± SD, 35.5±7.3) were randomly assigned to WB (n=15) and NWB (n=14) exercise groups. All participants (100%) completed the intervention and follow-up evaluations. InterventionsGroup-specific progressive balance, flexibility, strengthening, and aerobic exercise conducted sitting or lying (NWB) or standing and walking (WB) occurred 3 times a week for 12 weeks. Main Outcome MeasuresMeasures included the 6-minute walk distance (6MWD) and daily step counts. Secondary outcome measures represented domains across the International Classification of Functioning, Disability and Health. ResultsThe WB group showed greater gains than the NWB group over time on the 6MWD and average daily step count (P<.05). The mean and 95% confidence intervals (CIs) between-group difference over time was 29m (95% CI, 6–51) for the 6MWD and 1178 (95% CI, 150–2205) steps for the average daily step count. The NWB group showed greater improvements than the WB group over time in hemoglobin A1c values (P<.05). ConclusionsThe results of this study indicate the ability of this population with chronic disease to increase 6MWD and daily step count with a WB exercise program compared with an NWB exercise program.

Calf Stretching in Non-Weight Bearing Versus Weight Bearing

Limited ankle dorsiflexion passive range of motion (DF PROM) has been associated with lower extremity overuse injuries. Therefore, clinicians often prescribe stretching exercises to increase ankle DF PROM. However, there is limited evidence to indicate if any particular gastrocnemius stretching exercise results in greater improvement in DF PROM. The aim of this study was to determine if gastrocnemius stretching in non-weight bearing (NWB) or weight bearing (WB) results in a greater increase of ankle DF PROM. 28 healthy volunteers, aged 18-55 years, who exhibited less than 10 degrees of ankle DF PROM completed the study. Participants were randomized into 2 stretching groups: NWB and WB. Both groups completed a 3-week home gastrocnemius stretching program, consisting of 5 repetitions held for 30 s each, 2 times daily. Participants' ankle DF PROM was measured with a blinded standard goniometer in NWB and WB positions before and after participation in a 3-week home gastrocnemius stretching program. Two 3-way mixed model ANOVAs demonstrated no significant difference in ankle DF PROM between the NWB and WB groups for either the NWB measurement condition (p=0.49) or WB measurement condition (p=0.86). Gastrocnemius stretching exercises performed in NWB or WB were equally effective in increasing ankle DF PROM.

Journal Scan: Journal of Pediatric Orthopaedics

Here is my view of the top-10 most potentially influential papers from the Journal of Pediatric Orthopaedics from 2007. Included are the papers that were thought to provide the most useful examinations of treatments and outcomes.

Effect of immediate weightbearing on plated fractures of the humeral shaft.

This study evaluated the effect of immediate weightbearing on fractures of the humeral shaft treated with dynamic compression plates. Eighty-three fractures met the inclusion criteria. The weightbearing status of the humerus was based on associated injuries and not the fracture pattern. There were no differences between the weightbearing and nonweightbearing groups in patient or fracture demographics. Ninety-four percent of the fractures healed after the initial operation. Two in the nonweightbearing group and three in the weightbearing group required a second operation to achieve union. Alignment did not differ between the two groups. Immediate full weight. bearing had no effect on the union or malunion rate. When indicated, open reduction and internal fixation of the diaphysis of the humerus, followed by immediate weightbearing through the involved humerus, is a safe and efficacious procedure.

Effect of intermittent weight bearing on soleus fiber force-velocity-power and force-pCa relationships.

Rat permeabilized type I soleus fibers displayed a 33% reduction in peak power output and a 36% increase in the free Ca2+ concentration required for one-half maximal activation after 14 days of hindlimb non-weight bearing (NWB). We examined the effectiveness of intermittent weight bearing (IWB; consisting of four 10-min periods of weight bearing/day) as a countermeasure to these functional changes. At peak power output, type I fibers from NWB animals produced 54% less force and shortened at a 56% greater velocity than did type I fibers from control weight-bearing animals while type I fibers from the IWB rats produced 26% more absolute force than did fibers from the NWB group and shortened at a velocity that was only 80% of the NWB group mean. As a result, no difference was observed in the average peak power of fibers from the IWB and NWB animals. Hill plot analysis of force-pCa relationships indicated that fibers from the IWB group required similar levels of free Ca2+ to reach half-maximal activation in comparison to fibers from the weight-bearing group. However, at forces < 50% of peak force, the force-pCa curve for fibers from the IWB animals clearly fell between the relationships observed for the other two groups. In summary, IWB treatments 1) attenuated the NWB-induced reduction in fiber Ca2+ sensitivity but 2) failed to prevent the decline in peak power that occurs during NWB because of opposing effects on fiber force (an increase vs. NWB) and shortening velocity (a decrease vs. NWB).

EFFECT OF WEIGHT BEARING ON RETURN OF VASTUS MEDIALIS FUNCTION TWO WEEKS FOLLOWING ACL RECONSTRUCTION 159

Differences in rehabilitation exist with regard to the weight bearing status after ACL reconstruction. The purpose of this study was to examine the effect of early full weight bearing (WB) versus non weight bearing (NWB) on vastus medialis (VM) EMG activity, knee joint effusion and knee extension range of motion (KE ROM) two weeks following ACL reconstruction at which point crutch use is routinely discontinued. VM surface EMG activity, as an index of VM function, was quantified during four 5s contractions in attainable full extension (quad set). VM activity is reported as percent of normal knee. Effusion was graded as +3 (ballotable patella), +2 (visible and palpable fluid wave), +1 (fluid wave palpable but not visible) and 0 (no palpable fluid). All measurements were made two weeks prior and two weeks following surgery on 40 patients (21 men, 19 women). Patients were prospectively randomized into a non weight bearing group and a full weight bearing group.Table Patients had significant effusions 2 weeks post-op but degree of effusion was not different between groups. The decrease in VM activity was significantly greater in the NWB group (p<.0.01). KE ROM 2 weeks postop was not significantly different between groups. These data suggest that immediate full weight bearing following ACL reconstruction facilitates return of VM function. This may play a role in decreasing patellofemoral complications.

Soleus fiber force and maximal shortening velocity after non-weight bearing with intermittent activity.

This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type I fiber force (in mN), tension (Po; force per fiber cross-sectional area in kN/m-2), and maximal unloaded shortening velocity (Vo, in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca2+ activation, after which type I fiber myosin heavy-chain composition was confirmed by sodium dodecyl sufate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type I fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in Vo (+33%). In addition, NWB induced a 16% reduction in type I fiber Po, a 41% reduction in type I fiber peak elastic modulus [Eo, defined as (delta force/delta length) x (fiber length/fiber cross-sectional area] and a significant increase in the Po/Eo ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type I fiber diameter (by 36%), peak force (by 29%), and Vo (by 48%) but had no significant effect on Po, Eo, or Po/Eo. These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type I fiber atrophy and to partially restore type I peak isometric force and Vo to WB levels. However, the NWB-induced reductions in Po and Eo, which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.

Effects of function on rat femora

We evaluated the mechanical effects of different degrees of function and weight bearing on intact rat femora. Thirty rats were allocated to either an exercising, a nonweight-bearing, or a control group. The exercising rats were trained on a treadmill with a 6 weeks' running program of progressive intensity and duration. In the nonweight-bearing group, the left achilles tendon was severed at its insertion. The control rats were allowed normal activity. After 6 weeks, the animals were killed. The maximum bending moment and bending rigidity were increased in the exercised rats, whereas no differences were found between the control and nonweight-bearing rats. Bone weight and bone dimensions did not differ in the three groups. In the nonweight-bearing group, the maximum bending moment and bending rigidity were higher in the nonoperated on limb, as well as the outer and inner bone dimensions and the area moment of inertia. Our results indicate that exercise improves the mechanical characteristics of bone.