A model-based study of passive joint properties on muscle effort during static stance

This study examined the impact of lower extremity joint stiffnesses and simulated joint contractures on the muscle effort required to maintain static standing postures after a spinal cord injury (SCI). Static inverse computer simulations were performed with a three-dimensional 15 degree of freedom musculoskeletal model placed in 1600 different standing postures. The required lower extremity muscle forces were calculated through an optimization routine that minimized the sum of the muscle stresses squared, which was used as an index of the muscle effort required for each standing posture. Joint stiffnesses were increased and decreased by 100 percent of their nominal values, and contractures were simulated to determine their effects on the muscle effort for each posture. Nominal muscle and passive properties for an individual with a SCI determined the baseline muscle effort for comparisons. Stiffness changes for the ankle plantar flexion/dorsiflexion, hip flexion/extension, and hip abduction/adduction directions had the largest effect on reducing muscle effort by more than 5 percent, while changes in ankle inversion/eversion and knee flexion/extension had the least effect. For erect standing, muscle effort was reduced by more than 5 percent when stiffness was decreased at the ankle plantar flexion/dorsiflexion joint or hip flexion/extension joint. With simulated joint contractures, the postural workspace area decreased and muscle effort was not reduced by more than 5 percent for any posture. Using this knowledge, methods can be developed through the use of orthoses, physical therapy, surgery or other means to appropriately augment or diminish these passive moments during standing with a neuroprosthesis.     

Temporal changes in human temporomandibular joint size and shape

Measurements approximating the size of the temporomandibular joint were taken on a series of genetically homogeneous populations from early Nubia, which span almost 10,000 years and embody a shift from a primarily hunting and gathering adaptation to a completely agricultural lifeway. A generalized trend of reduction of temporomandibular joint size was observed. In addition, a decrease in sexual dimorphism was apparent for all measures of joint size; a change primarily mitigated by reductions in male dimensions. The observed variation in size and form of the temporomandibular joint is most likely the result of the reduction in masticatory muscle robusticity and resultant changes in craniofacial form which have been documented for the transition from a hunting and gathering to an agricultural subsistence in Nubia.     

The fasciocutaneous flap: a conservative approach to the exposed knee joint

The exposed knee joint poses a challenge to the reconstructive surgeon. The currently popular approach to the repair of exposed knee joints is use of muscle flaps. However, this leaves the patient with a deficit. We have therefore begun using the fasciocutaneous flap as an initial approach to this problem. In seven patients, aged 28 to 74 years, fasciocutaneous flaps have been the reconstructive procedure of choice for repair of exposed knee joints. One patient with a very large open wound required a concomitant medial gastrocnemius muscle flap. One minor wound separation occurred in a paraplegic patient with severe spasm. No other complications occurred. Follow-up ranged from 3 to 12 months, with good success in wound closure. An approach to small and intermediate wounds is presented in which the V-Y technique is used to obviate the need for skin grafting of the donor site.     

The role of intrinsic muscle flaps of the foot for bone coverage in foot and ankle defects in diabetic and nondiabetic patients

Local muscle flaps, pioneered by Ger in the late 1960s, were extensively used for foot and ankle reconstruction until the late 1970s when, with the evolution of microsurgery, microsurgical free flaps became the reconstructive method of choice. To assess whether the current underuse of local muscle flaps in foot and ankle surgery is justified, the authors identified from the Georgetown Limb Salvage Registry all patients who underwent foot and ankle reconstruction with local muscle flaps and microsurgical free flaps from 1990 through 1998. By protocol, flap coverage was the reconstructive choice for defects with exposed tendons, joints, or bone. Local muscle flaps were selected over free flaps if the defect was small (3 x 6 cm or less) and within reach of the local muscle flap. During the same time frame, the authors performed 45 free flaps (96 percent success rate) in the same areas when the defects were too large or out of reach of local muscle flaps. Thirty-two consecutive patients underwent local muscle flap reconstruction for 19 diabetic wounds and 13 traumatic wounds. All wounds, after debridement, had exposed bone at their base, with osteomyelitis being present in 52 percent of the diabetic wounds and in 70 percent of the nondiabetic wounds. Wounds were located in the hindfoot (47 percent), midfoot (44 percent), and ankle (9 percent). Vascular disease was more prevalent in the diabetic group, in which 42 percent of the affected limbs required revascularization procedures before reconstruction (versus 7 percent in the nondiabetic group). Subsequently, 83 total operations were required to heal the wounds, of which 46 percent were limited to debridement only. Thirty-four pedicled muscle flaps were used: 19 abductor digiti minimi (56 percent), nine abductor hallucis (26 percent), three extensor digitorum brevis (9 percent), two flexor digitorum brevis (6 percent), and one flexor digiti minimi (3 percent). An additional skin graft for complete coverage was required in 18 patients (53 percent). One patient died and one flap developed distal necrosis, for a 96 percent success rate. The complication rate was 26 percent and included patient death, dehiscence, and partial flap or split-thickness skin graft loss. Twenty-nine of the 32 wounds healed. One patient died in the postoperative period; in two others the wounds failed to heal and required below-knee amputations, for an overall limb salvage rate of 91 percent. Diabetes did not significantly affect healing and limb salvage rates. Diabetes, however, did affect healing times (twofold increase), length of stay (2.7 times as long), and long-term survival (63 percent survival in diabetic patients versus 100 percent in the trauma group). Local muscle flaps provide a simpler, less expensive, and successful alternative to microsurgical free flaps for foot and ankle defects that have exposed bone (with or without osteomyelitis), tendon, or joint at their base. Diabetes does not appear to adversely affect the effectiveness of these flaps. Local muscle flaps should remain on the forefront of possible reconstructive options when treating small foot and ankle wounds that have exposed bone, tendon, or joint.     

Mandibular retrusion, temporomandibular joint derangement, and orthognathic surgery planning.

One-hundred consecutive orthognathic surgery candidates with mandibular retrusion were selected for retrospective analysis. Patients had undergone imaging studies that included magnetic resonance imaging (MRI) of both temporomandibular joints to assess the presence or absence, stage, and activity of suspected internal derangement(s). Patients were divided into stable and unstable deformity groups based on the presence or absence of change in their facial contour and/or occlusal disturbances in the 24 months prior to evaluation. Each of the 58 unstable and 30 of 42 stable patients were found to have internal derangements of at least one temporomandibular joint. The degree of joint degeneration directly paralleled the severity of retrognathia in most cases. We concluded that temporomandibular joint internal derangement is common in cases of mandibular retrusion and leads to the facial morphology in a high percentage of patients. Preoperative temporomandibular joint imaging with MRI is recommended prior to orthognathic surgical correction of retrognathic deformities.     

Frequency and severity of musculoskeletal symptoms in humans during an outbreak of trichinellosis caused by Trichinella britovi

Musculoskeletal symptoms such as myalgia are well-known features in the course of trichinellosis; however, the characteristics of musculoskeletal findings have been described in detail in only 1 study. The present study was aimed to determine the joint and muscle symptoms in subjects diagnosed with acute trichinellosis at our rheumatology unit during a Trichinella britovi outbreak that occurred in Izmir, Turkey, in 2004. In total, 98 patients (55 females, 43 males; mean age 32.3 +/- 10.9 yr) were included in the study. A detailed history and full musculoskeletal examination were obtained in each patient. A self-administered questionnaire developed for recording the musculoskeletal symptoms was completed monthly until all the symptoms were resolved. Pain at the joints, restriction of movements (in shoulders, elbows, wrists, knees, ankles, and temporomandibular joints), myalgia, and muscle weakness (neck and shoulder girdle, muscles of the upper and forearm, back, thigh, and calf muscles) were assessed in every patient. Eosinophil counts, serum levels of creatine kinase, and lactate dehydrogenase also were analyzed. The most frequent musculoskeletal symptoms were muscle pain (86 cases [87.8%]), joint pain (83 [84.7%]), subjective muscle weakness (75 [76.5%]), and restriction of joint movements (63 [64.3%]). Calves, upper arm, neck and shoulder girdle, and forearms were the most affected muscle groups. Muscle pain was reported more frequently in the upper than in the lower extremities and during activity. The most frequent painful joints were shoulders, knees, wrists, and ankles. Upper extremity joints were affected more frequently than the lower extremity joints (77.6 vs. 70.4%). Joint pain occurred more frequently at rest. Both muscle weakness and restriction of joint movements were reported in and around the most frequently affected regions. No evidence of arthritis and objective muscle weakness was noted on physical examination in any patient. Musculoskeletal symptoms in the course of T. britovi infection are frequent but with an excellent prognosis. Joint pain in people suffering from acute trichinellosis may occur more frequently than reported previously.     

Large-volume circumferential liposuction with tumescent technique: a sure and viable procedure.

During a 4-year period, 152 female and 9 male patients underwent large-volume liposuction, with ages ranging from 19 to 65 years (mean of 36 years), with a weight previous to surgery between 57 and 126 kg (mean of 72 kg). Tumescent liposuction was done simultaneously by two surgeons in several corporal areas according to the necessities of each case. In 28 patients (17 percent), 500 ml of whole blood was required previous to the surgery by self donation. By means of liposuction, volumes between 5 and 22.3 liters (mean of 8.7 liters) were obtained with an average relation of 860 cc of fat for 140 cc of liquid. The reduction of hemoglobin and hematocrit at 1 week after surgery was of 3.8 g and 12 percent, respectively. The weight after surgery during the patient's follow-up varied from 54 to 111 kg, with an average of 66 kg. Major complications were not presented. Minor complications consisted of two superficial cutaneous necroses (1.2 percent) and 18 seromas (11.2 percent), which were drained without leaving sequelae; 24 patients (14.9 percent) presented postsurgical palpable irregularities, visible in only 8 patients (5 percent); 148 patients (92 percent) expressed important satisfaction with the results of the surgery, with the remaining 13 (8 percent) expressing some disagreement due to persistent irregularities. These complications had a direct relationship to some factors of the surgical technique and some characteristics of the patients. The amount of fat liposuctioned, the ideal height-weight relationship of the patient, the diameter of the cannulas used, and the experience acquired during the time were the most important factors that were associated with the complications. Based on these results, we concluded that large-volume circumferential liposuction with tumescent technique is a viable and sure alternative to achieve improvement of the body contour and weight loss.     

Histological study of the temporomandibular joint capsule: theory of the articular complex.

The findings of the histological study of the human temporomandibular joint confirm that the cranium and the lower jaw are jointed by two temporomandibular articular complexes (one on the left and another on the right side), each made up, in turn, of two joints--a condylomeniscal condyloarthrosis and a reciprocally fitting meniscotemporal joint. Both these joints are surrounded by short capsular bands which stretch from the condyle to the meniscus and from the latter to the temporal bone and form the true joint capsules. Longer bands which extend from the condyle to the temporal bone may be regarded as reinforcements passing over two articulations.     

Microvascular omental transfer for the treatment of severe recurrent median neuritis of the wrist: a long-term follow-up

The results of reoperation for recurrent carpal tunnel syndrome have been quite disappointing. In addition to a secondary external or internal neurolysis, multiple tissues and procedures have been used to decrease scar adherence of the reoperated median nerve including muscle, fascial or fat flaps, and vein wrapping. However, each technique has certain limitations, especially in the carpal tunnel that has previously undergone multiple operations, with diffuse scar and adherence over an extended length of the median nerve. The purpose of this study was to evaluate the long-term functional and symptomatic outcome following microvascular omental transfer for severe recalcitrant median neuritis. Between 1989 and 1993, 10 extremities in seven patients underwent omental transfer for severe recurrent median neuritis at the wrist. Nine extremities in six women were available for personal evaluation at an average follow-up of 6.6 years (range, 4.5 to 8.75 years). All extremities had undergone a minimum of two previous surgical procedures, and since 1991, all patients also failed local pedicle tissue coverage. Each patient completed a physical examination, a questionnaire, and electrophysiologic studies. At surgery, all median nerves were encased in dense adherent scar, which often extended proximal to the wrist crease. There were seven neural abnormalities in six extremities, three patent median arteries, and one aberrant palmaris longus muscle. The Functional Status Index was 3.1 +/- 0.7 and the Symptom Severity Index was 3.1 +/- 0.9, with a range of 1 (best) to 5. Most symptoms were improved but not completely alleviated. Four of nine extremities exhibited improved two-point discrimination and five of seven improved sensitivity, according to the Semmes-Weinstein monofilament test. Grip strength increased an average of 73 percent in seven of nine extremities and pinch strength increased 101 percent in four of nine extremities. Five of six patients were satisfied with their results and reported improved quality of life. Preoperatively, five of seven patients were working on light duty; postoperatively, three of six patients attempted to return to work, but none were working at final follow-up. Electrophysiologic data did not correlate with the symptomatic or functional outcome. There were four complications; three were related to delayed wound healing, and one morbidly obese patient developed a ventral hernia. Wrapping the median nerve with vascularized omentum is a viable option for the treatment of severe recalcitrant carpal tunnel syndrome. Despite a high satisfaction rate and significant symptomatic improvement, many symptoms will persist, but to a lesser degree.     

Management of complex groin wounds: preferred use of the rectus femoris muscle flap

This study reviews our experience with the rectus femoris muscle flap for complex groin wound reconstruction. Over the past 5 years, the rectus femoris has become our routine method of groin wound reconstruction. The rectus femoris is harvested through a midanterior incision extending over the distal two-thirds of the thigh. The muscle is elevated on its pedicle and transposed into the groin wound defect either directly or through an intervening skin bridge. Hospital and outpatient records were reviewed for all patients undergoing groin wound reconstruction with this technique from 1999 through 2003. Thirty-seven rectus femoris muscle flaps were performed in 33 patients. The mean patient age was 65.3 years (range, 25 to 88 years). Thirty groin wounds (81.1 percent) occurred after infrainguinal revascularization, 23 (76.7 percent) of which contained prosthetic material. Five (21.7 percent) of these wounds had their prosthetic material removed at the time of reconstruction. The remaining seven groin wounds (18.9 percent) occurred after femoral vessel cannulation for either cardiac or transplant surgery. There were no intraoperative mortalities and no anastomotic hemorrhages. There were no flap losses. Thirty-five of the 37 treated wounds healed (94.6 percent), 26 primarily (70.3 percent) and nine (24.3 percent) after delayed healing and contracture. Reoperation was performed in one patient for flap readvancement and in three patients for prosthetic graft removal after initial flap reconstruction. Two patients (6.1 percent) died during their hospitalization with persistent open groin wounds after flap reconstruction. All muscle flap donor incisions healed, with only two (5.4 percent) experiencing minimal delayed healing. There were no donor-site wound infections and no donor sites required reoperation. Thirty-three groin wounds (89.2 percent) demonstrated culture-positive microbial infection, 15 (45.5 percent) of which were polymicrobial. The 30-day mortality rate was 15.2 percent and the 6-month mortality rate increased to 27.2 percent, with multisystem organ failure as the most common cause. The rectus femoris muscle flap is an effective and reliable means of complex groin wound reconstruction. The muscle flap is dependable and the donor site is not problematic, even in the presence of peripheral vascular disease. On the basis of our clinical results, we believe that the rectus femoris muscle flap is the flap of choice for groin wound reconstruction.     

Sensitivity of temporomandibular joint force calculations to errors in muscle force measurements

A two-dimensional, five-muscle model was used to determine the degree of precision required for accurate calculation of temporomandibular joint force magnitude and direction. The sensitivity of the calculations to each variable were assessed by incrementing each variable through its presumed biological range and were expressed as rate of change in the joint force per unit change in each variable. Sensitivity of the calculations to variables depends upon both bite force direction and bite position. The bite force direction with maximum precision for joint force magnitude produced minimal precision for joint force direction. The accuracy needed for each muscle force varied greatly. The effect of error for each muscle parameter depended upon the magnitude, direction, and moment arm length of the muscle force relative to those of the resultant muscle force. If each of the five muscle forces was known to the nearest 1% of total muscle force magnitude, 1 degree of muscle force direction, and 1 mm of moment arm length, temporomandibular joint force magnitude could be calculated to the nearest 4 kg and joint force direction to the nearest 7 degrees. It is not known whether this precision for the muscle forces is possible.     

Ultrastructural abnormalities of muscle spindles in the rat masseter muscle with malocclusion-induced damage

Human temporomandibular disorders due to disturbed occlusal mechanics are characterized by sensory, motor and autonomic symptoms, possibly related to muscle overwork and fatigue. Our previous study in rats with experimentally-induced malocclusion due to unilateral molar cusp amputation showed that the ipsilateral masseter muscles undergo morphological and biochemical changes consistent with muscle hypercontraction and ischemia. In the present study, the masseter muscle spindles of the same malocclusion-bearing rats were examined by electron microscopy. Sham-operated rats were used as controls. In the treated rats, clear-cut alterations of the muscle spindles were observed 26 days after surgery, when the extrafusal muscle showed the more severe damage. The fusal alterations affected predominantly capsular cells, intrafusal muscle fibers and sensory nerve endings. These results suggest that in the malocclusion-bearing rats, an abnormal reflex regulation of the motor activity of the masticatory muscles may take place. They also allow us to hypothesize that muscle spindle alterations might be involved in the pathogenesis of human temporomandibular disorders.     

Facial deformity of juvenile rheumatoid arthritis

Arthritis of the temporomandibular joint and resulting deficient mandibular growth are seen in as many as 25 percent of patients with juvenile rheumatoid arthritis. The magnitude of joint involvement and resulting growth deficiency varies significantly. These patients typically develop a "birdface" deformity with retruding mandible, alteration of the cervicofacial angle, and class II occlusion with limitation of the bite opening. A multidisciplinary approach, including the surgeon, a dentist, an orthodontist, and a rheumatologist, is necessary to ensure a safe and successful surgical outcome. The side effects of pharmacologic agents used to control the disease on coagulation, healing, and bone density should be considered seriously.     

Influence of the method of TM joint total replacement implantation on the loading of the joint on the opposite side

The temporomandibular (TM) joint is one of the most used joints in the human body, and any defect in this joint has a significant influence on quality of life. The objective of this study was to create a parametric numerical finite element (FE) analysis to compare the effect of surgical techniques used for total TM joint replacement implantation on loading the TM joint on the other side. Our hypothesis is that for the optimal function of all total TM joint replacements used in clinical practice it is crucial to devise a minimally invasive surgical technique, whereby there is minimum resection of masticatory muscles. This factor is more important than the design of the usually used total TM joint replacements. The extent of muscle resection influences the mechanical loading of the whole system. In the parametric FE analyses, the magnitude of the TM joint loading was compared for four different ranges of muscle resections during bite, using an anatomical model. The results obtained from all FE analyses support our hypothesis that an increasing extent of the muscle resection increased the magnitude of the TM joint overloading on the opposite side. The magnitude of the TM joint overloading increased depending on the muscle resection to 235% for bite on an incisor and up to 491% for bite on molars. Our study leads to a recommendation that muscle resection be minimised during replacement implantation and to a proposal that the attachment of the condylar part of the TM joint replacement be modified.     

Influence of the method of TM joint total replacement implantation on the loading of the joint on the opposite side

The temporomandibular (TM) joint is one of the most used joints in the human body, and any defect in this joint has a significant influence on quality of life. The objective of this study was to create a parametric numerical finite element (FE) analysis to compare the effect of surgical techniques used for total TM joint replacement implantation on loading the TM joint on the other side. Our hypothesis is that for the optimal function of all total TM joint replacements used in clinical practice it is crucial to devise a minimally invasive surgical technique, whereby there is minimum resection of masticatory muscles. This factor is more important than the design of the usually used total TM joint replacements. The extent of muscle resection influences the mechanical loading of the whole system. In the parametric FE analyses, the magnitude of the TM joint loading was compared for four different ranges of muscle resections during bite, using an anatomical model. The results obtained from all FE analyses support our hypothesis that an increasing extent of the muscle resection increased the magnitude of the TM joint overloading on the opposite side. The magnitude of the TM joint overloading increased depending on the muscle resection to 235% for bite on an incisor and up to 491% for bite on molars. Our study leads to a recommendation that muscle resection be minimised during replacement implantation and to a proposal that the attachment of the condylar part of the TM joint replacement be modified.     

Evaluating rejuvenation of the forehead and brow: an algorithm for selecting the appropriate technique

The traditional reason for performing aesthetic surgery in the forehead and brow area has been to correct brow ptosis. However, there are several other conditions that may be improved by surgery in this area, including frown muscle imbalance, transverse forehead rhytids, and lateral brow laxity. Recently, a better understanding of the relevant anatomy and the evolving therapeutic modalities (including both open and closed techniques) have contributed to a renewed interest in aesthetic surgery in the forehead and brow area. One hundred consecutive patients were studied, each of whom underwent forehead rejuvenation for one of four indications-forehead rhytids, glabellar creases, lateral brow laxity, or brow ptosis. Thirty-eight percent of patients underwent open procedures, 30 percent underwent closed procedures, and 32 percent underwent limited procedures. Complications occurred in 4 percent of patients, including three patients who were dissatisfied with the surgery and one patient who required scar revision. Based on our findings, we formulated an algorithm that integrates the different indications and any concomitant procedures being performed. Our proposed treatment plan is based on this information. The algorithm may be used as a template when assessing a patient and adapting the recommended intervention to the individual patient.     

Microsurgical hypospadias repair

Successful primary hypospadias repair depends on careful execution of surgical principles, particularly during the urethroplasty portion of the procedure. These principles include careful tissue handling, development of well-vascularized flaps, and avoidance of placing sutures in the uroepithelial surface. Despite meticulous repair, the complication rate requiring secondary surgery is 15 to 30 percent. For the past year, the authors have utilized an operating room microscope, microsurgical instruments, a specially designed microsuture, and a Biooclusive dressing to decrease the postoperative morbidity and subsequent complications requiring secondary surgery (6.5 percent). A comparison of 50 hypospadias patients on whom no microsurgical repair had been used was made with 62 patients on whom microsurgical techniques were employed. The nonmicrosurgical group had 17 complications, 12 of which required reoperation (24 percent). The microsurgical group had 8 complications, 4 of which required reoperation (6.5 percent).     

Unpredictable growth pattern of costochondral graft.

Costochondral grafts have gained increasing popularity in reconstruction of the temporomandibular joint and condyle in children. This is a report on the long-term follow-up of eight adolescent patients who underwent reconstruction of the temporomandibular joint and ramus for correction of hemifacial microsomia or trauma-related temporomandibular joint ankylosis during varying periods of growth. Six patients had hemifacial microsomia, and two suffered from posttraumatic temporomandibular joint ankylosis. Average follow-up was 80.4 months. Four patients had excessive growth of the graft, one patient had suboptimal growth, and three patients had no growth. In addition, one patient had undergone four procedures for significant graft overgrowth. Based on this study and review of the literature, we have concluded that the growth pattern of the costochondral graft is extremely unpredictable, ankylosis is a common problem following a temporomandibular joint reconstruction with costochondral graft, and mandibular overgrowth on the grafted site can actually be more troublesome than the lack of growth. Furthermore, maxillary growth is proportionately influenced by vertical mandibular growth of the graft, while the horizontal maxillary growth is not altered. Ankylosis is a result of ossification of the cartilaginous portion and the three-dimensional graft overgrowth, aggressively extending beyond the cartilage graft boundary. Based on this study, we recommend that this procedure be performed only on severe deficiencies. Adequate amounts of soft tissue should be retained between the skull base and the graft, and we further recommend harvesting the graft from the fourth or fifth rib, which may reduce the potential for overgrowth.(ABSTRACT TRUNCATED AT 250 WORDS)