Decreased Weight Bearing Research Articles

Bone health in haemophilia carriers and persons with von Willebrand disease: A large database analysis.

Persons with haemophilia(PWH) have been shown to have low bone mineral density likely the result of prolonged immobility, recurrent hemarthrosis, decreased weight bearing, lower physical activity level and obesity. Bone health has been poorly characterized in haemophilia carriers (HC) and persons with von Willebrand disease (PWvWD). To estimate the prevalence of osteoporosis, osteoarthritis and bone fractures in HC and PWvWD and identify risk factors for poor bone health. This is a retrospective study using a population level, commercial database - Explorys (IBM Watson Health, Cleveland, USA). We compared prevalence rates of osteoporosis, osteoarthritis and fractures among cases (HC or PWvWD) and controls (general population without an underlying bleeding disorder) from 1999 to 2020. Prevalence of common risk factors for poor bone health were compared among cases and controls. Among 72,917,850 active persons in the database, we identified 940 women with the diagnosis of HC and 19,580 PWvWD. Among HC and PWvWD, prevalence of osteoporosis, osteoarthritis and fractures were significantly higher in cases, when compared to controls. In HC, the prevalence of vitamin D deficiency, obesity, hypothyroidism, smoking, diabetes mellitus, hypocalcaemia, corticosteroid use, malignancy, renal failure and Nonsteroidal anti-inflammatory drugs (NSAID) use were significantly higher among the cases. In PWvWD, the prevalence of risk factors was significantly higher in cases when compared to controls. The prevalence of osteoporosis, osteoarthritis and fractures is significantly higher among HC and PWvWD. This data highlights the importance of screening patients for risk factors for poor bone health and provide education to prevent these complications.

Parathyroid hormone-(1-34) ameliorated knee osteoarthritis in rats via autophagy.

Anterior cruciate ligament (ACL) tear can lead to osteoarthritis (OA). However, parathyroid hormone (PTH)-(1-34) was found to alleviate OA progression in a papain-induced OA model. Autophagy is a protective mechanism in normal cartilage, and its aging-related loss is linked with chondrocyte death and OA. Thus we examined the roles of autophagy in PTH treatment in OA after ACL transection (ACLT). Thirty-six rats were randomized into three groups: control group, ACLT-induced OA (OA) group, and OA with intra-articular PTH-(1-34) treatment (OA+PTH) group. Weight-bearing and treadmill tests were evaluated. Cartilage matrix was determined by a histological evaluation of glycosaminoglycan (GAG), Osteoarthritis Research Society International (OARSI) score, chondrocyte apoptosis, and immunohistochemistry. Rats in the OA group had significantly decreased weight bearing and running endurance. The histological results indicated that GAG, collagen type II, and chondrocyte autophagy had decreased but that the OARSI score, terminal differentiation markers (collagen type X and Indian hedgehog), and chondrocyte apoptosis had increased in the OA group. Additionally, PTH-(1-34) treatment significantly improved weight bearing and treadmill endurance, preserved GAG and collagen type II, and reduced the OARSI score and terminal differentiation markers. Finally, PTH-(1-34) ameliorated chondrocyte apoptosis by regulating the expression of autophagy-related proteins, through reducing mechanistic target of rapamycin (mTOR) and p62 and enhancing microtubule-associated protein-1 light chain 3 (LC3) and beclin-1. Reconstructive surgery after ACL rupture cannot prevent OA occurrence. Intra-articular PTH-(1-34) treatment can alleviate OA progression after ACLT and histological molecular changes. Possible mechanisms are reducing chondrocyte terminal differentiation and apoptosis, with increasing autophagy. NEW & NOTEWORTHY Anterior cruciate ligament (ACL) tear can lead to osteoarthritis (OA). Intra-articular parathyroid hormone (PTH)-(1-34) significantly improved weight bearing and treadmill endurance, preserved glycosaminoglycan and collagen type II, and reduced Osteoarthritis Research Society International (OARSI) score and terminal differentiation. Finally, PTH-(1-34) ameliorated chondrocyte apoptosis by regulating the expression of autophagy-related proteins, through reducing mechanistic target of rapamycin (mTOR) and p62 and enhancing microtubule-associated protein-1 light chain 3 (LC3) and beclin-1. PTH-(1-34) can alleviate OA progression after ACL transection. Possible mechanisms are reducing chondrocyte terminal differentiation and apoptosis, with increasing autophagy.

Kinetic gait analysis in English Bulldogs

BackgroundCanine breed conformation may interfere with locomotion and may predispose to orthopedic disease. Bulldogs have a high incidence of orthopedic diseases such as hip dysplasia. Kinetic gait analysis provides an objective way to assess and analyze locomotion. The aim of this study was to study the vertical forces of English Bulldogs during walk using a pressure sensitive walkway. We hypothesize that Bulldogs affected by orthopedic diseases have decreased weight bearing and asymmetric locomotion in the limbs despite having mild to no sings during clinical examination. Thirty English Bulldogs were tested. Peak vertical force, vertical impulse, rate of loading, stance phase duration, symmetry index, goniometry and incidence of orthopedic diseases were recorded.ResultsAlthough none of the dogs showed signs of pain or discomfort upon manipulation of the hip joints, all dogs had radiographic evidences of hip dysplasia and lack of significant peak vertical force, vertical impulse and stance time differences. The dogs had a mean hind limb symmetry index of 19.8 ± 19.5% and rates of loading ranged from 1.0 to 3.1.ConclusionsDespite the lack of evident decrease in weight bearing, subclinical lameness can be inferred. The examined dogs had a mean hind limb symmetry index of 19.8 ± 19.5%. Symmetry indices reported in dogs free from orthopedic diseases range from 0.3 to 9.6%. Given non-lame dogs are expected to have a symmetry index close to 0%, data from this study suggests that Bulldogs have gait dysfunctions, which translates into hind limb asymmetries and rate of loading was consistent with severe hip dysplasia despite no visible signs of gait dysfunction. Future studies comparing lame and non-lame Bulldogs are warranted.

Why Owners Choose an Orthosis Over Stifle Surgery for Canine Cranial Cruciate Ligament Deficiency

The objective of this study was to describe the patient population of dogs with cranial cruciate ligament (CrCL) deficiency that were prescribed a stifle orthosis. A total of 215 client-owned dogs with previously diagnosed CrCL deficiency were prescribed a stifle orthosis at a veterinary pain management and mobility clinic. Patient intake data collected included dog signalment, chief medical complaint, home environment and activity description, medical and surgical history, and diagnosing veterinarian. An orthopedic examination was conducted to assess pelvic limb function and determine pelvic limb morphologic measures. Spayed females (57.2%) were most common in our sample. Median age, body weight, and body condition score were 9.00 ± 3.23 years, 32.98 ± 13.37kg, and 6.00 ± 1.04, respectively. Most common breeds prescribed stifle orthoses included Labrador Retriever, Golden Retriever, and German Shepherd. Right and left limbs were equally affected, and 19.5% of dogs previously had stifle stabilization surgery. Primary reasons for seeking a stifle orthosis consultation were surgical concerns, advanced age, and surgery cost. Most common chief complaints included altered gait, decreased weight bearing, and pain following activity. Reduced stifle extension, increased cranial drawer score, and decreased 3-leg stance time characterized the CrCL-deficient stifle. Stifle orthosis represents an alternative approach to surgical stabilization and management of CrCL deficiency. CrCL-deficient dogs prescribed stifle orthoses were generally large breeds of advanced age with above ideal body condition score. Owners commonly sought a stifle orthosis for CrCL deficiency due to reservations regarding surgical management.

Knee osteoarthritis pain following medial meniscectomy in the nonhuman primate

A number of promising compounds developed for osteoarthritic pain have failed to demonstrate clinical efficacy. To enhance preclinical translational research for osteoarthritis, a model of knee osteoarthritis pain was developed in Macaca fascicularis and the effects of two distinct pharmacological classes of drugs were tested on pain-related behavior. Behavioral assessments were developed specifically for the macaque. Baseline knee pressure threshold and weight bearing were assessed prior to a unilateral medial meniscectomy (MMx). Fifteen days following MMx, macaques underwent a once daily exercise regimen for 36 days. Sixty-seven days following MMx, macaques were assigned to one of three treatment groups (n=3/group), either non-steroidal anti-inflammatory drug (NSAID) diclofenac, NK1 receptor antagonist aprepitant or vehicle, and treated for 5days. Animals were tested 3-4h after p.o. dosing and testing was performed blinded. Treatment utilized a crossover design-each animal received all treatments-and a 9-day washout period was utilized between treatments. Vehicle-treated macaques consistently demonstrated decreased ipsilateral pressure threshold ("hyperalgesia") and decreased weight bearing. While diclofenac increased weight bearing and pressure threshold, full attenuation of pain was not obtained. No significant improvement of either knee pressure or weight bearing was observed with aprepitant. Unilateral MMx in the macaque evoked pain-related behaviors and knee joint pathology reminiscent of osteoarthritis. The behavioral endpoints were sensitive to NSAID treatment but not sensitive to NK1 receptor block, which parallel clinical findings. The current macaque osteoarthritis model could be used to test potential treatments for osteoarthritis pain.

Vertical force analysis in dogs with hip osteoarthritis undergoing treatment with chondroprotectors

This study was aimed at evaluating vertical forces generated during locomotion in dogs affected with hiposteoarthritis (OA) submitted to chondroprotective treatment with chondroitin sulphate and lucosamine(CS-GLU). Eighteen dysplastic dogs suffering from secondary bilateral hip OA and treated with CS-GLU(200mg and 300mg/10kg/SID respectively) for 60 days (treated group), and 18 lameness free dogs withnormal hip joints (healthy group) were evaluated. A pressure sensitive walkway was used to measure peakvertical force (PVF), vertical impulse (VI) and stance phase (SP) duration. Data collection was performed prior to and within 30 and 60 days of treatment (treated group), or on a single occasion (healthy group). Longitudinal and intergroup comparisons were made using repeated measures ANOVA followed by the Tukey post-hoc test and the unpaired t-test respectively, with a significance level of 5% (p<0.05). Mean peak vertical force did not differ significantly within the treated group. However, mean PVF and VI were lower in the treated compared to the control group. A slight increase in mean VI was documented in one treated limbat time points 30 and 60. Results of this study suggest hip OA leads to decreased weight bearing and treatmentwith CS-GLU does not improve PVF in the short term.

Nutritional status and growth in children with cerebral palsy: a review

The objective of this work was to review the studies conducted among developing and developed countries to assess the growth pattern and nutritional status of children with cerebral palsy. It also aimed at summarizing the key factors responsible for high prevalence of undernutrition among them. Significant reductions in the anthropometric parameters were found in children with cerebral palsy as compared to their nondisabled counterparts. This deviation from normal growth can be attributed to inadequate dietary intake, feeding problems, decreased weight bearing, and several nonnutritional factors including abnormal endocrine function, socioeconomic status, disease severity, and age. Also, it was seen that undernutrition was more prevalent among developing countries as compared to developed countries. Besides undernutrition, various studies conducted among developed countries have reported a high prevalence of overweight and obesity among this population. This could be attributed to a decrease in the motor function because of the underlying condition and an increase in the gastrostomy feeding owing to availability of better health care facilities.

Analgesic Effect of Intra-Articular Injection of Temperature-Responsive Hydrogel Containing Bupivacaine on Osteoarthritic Pain in Rats

The present study examined the analgesic effects of slow-releasing bupivacaine from hydrogel on chronic arthritic pain in rats. Osteoarthritis (OA) was induced by monosodium iodoacetate (MIA) injection into the right knee joint. Hydrogel (HG: 20, 30, and 50 μL) and temperature-sensitive hydrogel containing bupivacaine (T-gel: 20, 30, and 50 μL) were injected intra-articularly 14 days after MIA injection. Behavioral tests were conducted. The rats showed a significant decrease in weight load and paw withdrawal threshold (PWT). Intra-articular 0.5% bupivacaine (10 and 20 μL) significantly reversed MIA-induced decreased PWT, with no effect on weight load. In normal rats, hydrogel did not produce significant changes in PWT but at 30 and 50 μL slightly decreased weight bearing; T-gel did not cause any changes in both the weight load and PWT. In OA rats, T-gel at 20 μL had a significant analgesic effect for 2 days, even though T-gel at 50 μL further reduced the weight load, demonstrating that intra-articular T-gel (20 μL) has long-lasting analgesic effects in OA rats. Thus, T-gel designed to deliver analgesics into the joint cavity could be an effective therapeutic tool in the clinical setting.

Orthostatic Tremor in Two Siblings (P04.050)

Objective: To report the occurrence of orthostatic tremor (OT) in two siblings. Background OT is an infrequently diagnosed form of tremor in which patients experience tremor in the legs upon standing. The tremor is usually relieved by the initiation of movement or decreased weight bearing. OT has rarely been reported to co-occur within families; indeed there are only two prior reports of OT in siblings. The presence of such cases raises the possibility that susceptibility genes could contribute to the etiology of this disease. Design/Methods: Case reports with clinical and clinical neurophysiologic assessments. Results: A brother (age 79) and sister (age 75) who both had onset of tremor at age 73 were seen in our movement disorders center. Both described tremor in the legs upon standing, which was relieved by walking or sitting. The tremor was accompanied by the sensation of imbalance, and falls in the brother, and the use of a walker for stability in the sister. No other family members had OT, including both parents and three other siblings. On examination, both developed visible tremor in the legs soon after standing. Both had mild kinetic and intention tremor in the upper extremities. Tremor analysis with EMG was performed, and in both siblings, standing induced 13.5 Hz synchronized agonist-antagonist burst discharges in the tibialis anterior and gastrocnemius muscles. When standing on one leg, the tremor was only evident in the weight-bearing leg. Both experienced improvement on clonazepam, however the dose was limited by side effects in each (1mg/day in the sister and 2 mg/day in the brother). Conclusions: This report of electrophysiologically-confirmed OT in siblings raises a possible genetic etiology in these cases. Supported by: Supported in part by the Parkinson9s Disease Foundation (S.L.P. and T.V.). Disclosure: Dr. Virmani has nothing to disclose. Dr. Louis has nothing to disclose. Dr. Waters has received personal compensation for activities with Boehringer Ingelheim Pharmaceuticals, Inc., Novartis, and Teva Neuroscience as a speaker. Dr. Pullman has nothing to disclose.

Spontaneous firing in C-fibers and increased mechanical sensitivity in A-fibers of knee joint-associated mechanoreceptive primary afferent neurones during MIA-induced osteoarthritis in the rat

Osteoarthritis (OA) pain mechanisms are poorly understood. We used the monosodium iodoacetate (MIA) model of knee OA to characterize changes in excitability during the course of OA in different classes of mechanosensitive afferents projecting to joint-associated tissues, and examine whether these afferent responses and pain behavior are correlated. Rats were injected intra-articularly with MIA (1mg in 50 μl). Hind-limb weight bearing was studied 3 (MIA3) and 14 (MIA14) days after MIA, followed by deep anesthesia and teased-nerve-fiber recordings. Spontaneous activity (SA) and mechanically evoked responses of A- and C-mechanosensitive fibers (AM and CM respectively, probably nociceptive) innervating tissues associated with the ipsilateral knee joint were examined. MIA3 and MIA14 rats exhibited reduced ipsilateral weight bearing. SA (>0.02 impulses/s) occurred in ∼50% of CMs from MIA rats vs 0% in normals. SA firing rates in CMs were significantly higher than normal; decreased weight bearing was correlated with increased CM SA rates. Neither percentages of AMs with SA (20%) nor their firing rates (0-0.01 impulses/s) significantly increased after MIA. In contrast, in MIA rats AMs, but not CMs, exhibited decreased mechanical thresholds and increased firing rates in response to suprathreshold mechanical stimulation. These findings of increased SA firing rate in CMs but not AMs and increased mechanical sensitivity of AMs, but not CMs, have not previously been reported. These are two distinct important physiological mechanisms that may underpin spontaneous pain (CMs) and stimulus-evoked pain (AMs) in OA. Our data contribute to a mechanism-based understanding of OA pain.

Pediatric Pelvic Osteomyelitis

Pelvic osteomyelitis is unusual in children. We retrospectively reviewed charts of patients with this infection seen at our institution. From 1998 to 2005, 31 patients with pelvic osteomyelitis were identified: 19 males and 12 females with an age range of 1.5 months to 17 years 9 months. Duration of illness prior to admission ranged from 1 day to 2.5 months. Chief complaints included nonspecific pain, fever, limp, and decreased weight bearing. Microorganisms isolated included Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella, Enterobacter cloacae, and Kingella kingae. Bones involved were acetabulum/ilium (22 patients), ischium (7 patients), and pubis (4 patients); 2 patients had several bones involved. Imaging studies performed included magnetic resonance imaging (21 patients), computed tomography (14 patients), and nuclear bone scan (25 patients). Our study, the largest contemporary series of pediatric pelvic osteomyelitis from one institution, highlights the consequences of prolonged duration of illness and delayed diagnosis.

Isokinetic dynamometry and electromyographic activity (sEMG) after anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon autografts

Isokinetic dynamometry and electromyographic activity (sEMG) after anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon autografts D. Mourauxa, P.-M. Dugaillya, E. Brassinnea and M. Vancabekeb Department of Physical Therapy and Rehabilitation, Erasmus Hospital, ULB, Brussels, Belgium Department of Orthopaedics Surgery, Brugmann Hospital, Brussels, Belgium Introduction: Quadriceps weakness after injury and reconstruction of anterior cruciate ligament (ACL) is well documented. This amyotrophy in the immediate postoperative period is related to several factors, such as decreased weight bearing, knee joint effusion, pain, harvesting of the tendon graft and neuromuscular factors [1]. The present study is designed to compare the short outcome of strength and EMG recruitment pattern of quadriceps and hamstring between 3 months postoperatively for an ACL reconstruction with hamstring tendon autografts fixed patients and a healthy control group. Methods: Thirteen healthy male students (mean age: 24 years, weight: 77 kg, height: 181 cm) participated in the study. They had no history of knee or hip injuries. They were compared to 19 patients (mean age: 31 years, weight: 80 kg, height: 180 cm) who had surgery for ACL reconstruction with hamstring tendon autografts precisely 3 months before these assessments. Patients were excluded if there were any other lesions in the same knee. In both groups the subjects were recreational athletes. All subjects were familiarized with isokinetic movements in concentric (CON) or ecTable 1 Mean ± standard deviation of quadriceps and hamstrings Peak Torque (PT). Comparison between control legs and UninvolvedInvolved legs. ∗Significant at p < 0.05 level Control Uninvolved Involved Quad PT Con 180◦/s 136 ± 23 125 ± 37 93 ± 28∗ Quad PT Con 60◦/s 193 ± 30 183 ± 30 118 ± 47∗ Ham PT Con 180◦/s 101 ± 16 89 ± 30∗ 85 ± 9∗ Ham PT Con 60◦/s 137 ± 18 118 ± 22∗ 101 ± 33∗ Ham PT Ecc 30◦/s 178 ± 13 146 ± 20∗ 113 ± 10∗ centric (ECC) contraction. The tests were performed with a CYBEX NORM consisting in 3 maximal dynamic contractions at 180◦/s and 60◦/s in CON (for both flexor and quadriceps muscles) and at 30◦/s in ECC (for flexor). During these tests, the sEMG activity was recorded from the vastus lateralis (VL), the vastus medialis (VM) the rectus femoris (RF) and the mass of the hamstring by the Noraxon Myosystem 2000. The exercices were performed at a range of motion from 0◦ to 105◦. All electrical activities were expressed in microvolt (μV). Influence of independent variables was analysed using multivariate analysis of variance

“Phantom” carpal tunnel syndrome

Phantom sensation is ubiquitous among persons who have had amputation; however, if it develops into phantom pain, a thorough clinical investigation must ensue. We illustrate this with the case of a 49-year-old woman, 14 years after traumatic amputation of her left 2nd through 5th fingers, and 10 years after traumatic left transfemoral amputation. She had had phantom sensation in her absent fingers for years and developed progressive pain in her phantom fingers 3 months before presentation. Nerve conduction study revealed a high-normal distal motor latency of the left median nerve and a positive Bactrian test (sensitivity 87%). She was diagnosed with “phantom” carpal tunnel syndrome and treated with a resting wrist splint, decreased weight bearing on the left upper limb, and two corticosteroid carpal tunnel injections with marked improvement. Clinicians should recognize that phantom pain may be referred from a more proximal region and may be amenable to conservative management.

Adaptation of the skeletal muscle calcium-release mechanism to weight-bearing condition.

In the present study, we examined whether weight-bearing condition can regulate the sarcoplasmic reticulum (SR) Ca(2+)-release mechanism. Measurements of alpha 1-subunit dihydropyridine (alpha 1-DHP) and ryanodine receptor levels were made in hypertrophied fast-twitch plantaris muscles 5 wk after surgical removal of synergist muscles (increased weight bearing) and in atrophied slowtwitch soleus muscles (14 days of non-weight bearing) of the rat. Rates of AgNO3-induced SR Ca2+ release were measured with fura 2 as the Ca2+ indicator and pyrophosphate as the precipitating ion during vesicular Ca2+ loading. Ca(2+)-release rates were 38, 49, and 58% lower in vesicles from hypertrophied vs. control muscles at AgNO3 concentrations of 0.05, 0.5, and 5 microM, respectively (control = 18.2 +/- 1.4 microM.mg-1. min-1). Western blots showed no differences in the relative expression of alpha 1-DHP or ryanodine receptor when IIID5 (monoclonal) or GP3 (polyclonal) antibodies were used. There was also no difference in ryanodine (10 nM) binding in Ca(2+)-incubated SR vesicles from hypertrophied muscles, suggesting no difference in the number of channels. In contrast, expression of alpha 1-DHP and ryanodine receptors was increased by 144 and 157% in non-weight-bearing soleus muscles, respectively. Scatchard analysis of DHP binding showed a 40% increase in maximum binding capacity and no change in the dissociation constant with non-weight-bearing muscles. The direction of modification of the SR Ca(2+)-release mechanism is opposite with increased and decreased weight bearing, but the mechanism by which this is achieved appears to be different.

Femoral Head Excision Arthroplasty Using the Vascularised Rectus Femoris Muscle Sling

SummaryRectus femoris muscle slings were transposed over femoral head ostectomy sites in four large breed dogs, while in three other dogs, standard femoral head and neck excision arthroplasty was performed. After the operation two dogs, with rectus femoris muscle slings, showed transient swelling of the operated limb and remained weight bearing minimally throughout the 28-day study period. In the two remaining dogs with muscle transposition, the surgical sites were normal, but decreased weight bearing and marked lameness were apparent. The dogs with standard femoral head excisions did not have any postoperative problems with the surgical sites and were weight bearing, with slight to moderate gait abnormalities, after the operation. All of the dogs showed decreases in coxofemoral range of motion, standing hip angle and limb length of the operated leg but postoperative differences between the two treatment groups were not significant. Thigh muscle circumference was significantly less in dogs with rectus femoris muscle slings than those with standard femoral head excision. Extensive perfusion of transposed slings was apparent on angiographic studies. Histopathology of muscle slings showed focal inflammation, muscle fibre atrophy and fibrosis with intact neurovascular supply.Femoral head excisional arthroplasty was performed in seven large breed dogs, four of which had adjunctive rectus femoris muscle slings trans-posed over ostectomy sites. Although the rectus femoris muscle sling remained vascular and was associated with minimal immediate postoperative complications, dogs with muscle transposition showed decreased weight bearing, more obvious lameness and a slower return to function, than dogs with standard femoral head and neck excision. Dogs with rectus femoris muscle slings did not show any improvement in coxofemoral range of motion, standing hip angle or limb length, rather more thigh muscle atrophy was evident on day 28 after surgery.

Using Might Splints in the Treatment of Plantar Fasciitis in the Athlete

Plantar fasciitis is one of the most common foot injuries athletes sustain. The painful heel is the result of overloading and inflammation of the plantar fascia at its insertion into the medial process of the tuberosity of the calcaneus. Many different treatment approaches have been used to address this overuse problem. Treatment for plantar fasciitis has included decreased weight bearing, nonsteroidal anti-inflammatory drugs (NSAIDs), orthotics, arch taping, weight loss, steroid injections, ultrasound, ice, physical therapy, and surgical release. Clinically the use of night splints has been found to be very successful in the treatment of plantar fasciitis, as described in this case study.

Postnatal contracture of young horses

Summary Three forms of postnatal contractures of the forelimb of young horses are: primary suspensory ligament contracture, primary deep flexor contracture, and combined contracture (pain contracture). Mechanical models are developed which demonstrate theoretically that (1) suspensory contracture is the result of a too small hoof angle followed and/or accompanied by a too rapid increase of the weight borne by the leg (whether as the result of lameness or too large a rate of gain of body weight). (2) Deep flexor contracture is the result of inadequate wearing of the bearing surface of the hoof wall, however induced, (3) Pain contracture is the result of decreased weight bearing. In all cases the contracture progresses as the shortened tendons cross-link and thereby become stronger in the shortened position. Once the cycleof suspensory contracture has been induced, secondary shortening of the superficial flexor, and eventually the deep flexor, can occur. There is less tendency for secondary contracture with primary deep flexor contracture, though the superficial flexor may shorten in an advanced case. The absence of clinically obvious postnatal contractures of the rearlegs is related to the fact that the deep flexor check ligament is small or absent in the rearleg and therefore to the fact that the deep flexor operates over the tibiotarsal as well as the coffin and fetlock joints.