Neuromuscular function after muscle fatigue in Charcot-Marie-Tooth type 1A patients.

INTRODUCTION: The effect of recovery time on neuromuscular function after a fatiguing task was compared in both the upper and lower limbs between patients with Charcot-Marie-Tooth type 1A (CMT1A) and healthy individuals. METHODS: Torque of elbow flexors and knee extensors and surface electromyography (sEMG) data of biceps brachii and vastus lateralis were recorded from 8 CMT1A patients and 8 matched, healthy individuals during maximal voluntary contraction (MVC) before (pre-fatigue MVC), 10 s after (10-s post-fatigue MVC), and 10 min after (10-min post-fatigue MVC) a fatiguing task at 80% MVC until exhaustion. RESULTS: Only in the lower limb, torque and root mean square of sEMG (RMS) during pre-fatigue MVC were lower (P < 0.05) in patients (91.93 ± 45.95 Nm, 0.11 ± 0.07 mV) than in controls (161.06 ± 75.5 Nm, 0.24 ± 0.16 mV). In the 10-min post-fatigue MVC, muscle-fiber conduction velocity (MFCV) and RMS, expressed as a percentage of pre-fatigue MVC, were lower (P < 0.05) in patients (MFCV 90.3 ± 6.91%, RMS 84.50 ± 9.89%) than in controls (MFCV 100.87 ± 5.1%, RMS 92.71 ± 11.84%). CONCLUSIONS: CMT1A patients are not only weaker than healthy individuals in the knee extensors, but they also have impaired neuromuscular recovery after fatigue.

Calf serum constituent fractions influence polyethylene wear and microbial growth in knee simulator testing.

Calf serum lubricants consisting of various polypeptide constituent fractions are routinely used in knee wear simulators as part of the standardized test protocol. Three calf sera (bovine, new-born and alpha) were diluted as per the recommendation of ISO 14243-3 and used in displacement-controlled knee wear simulators to investigate their effects on polyethylene wear. Biochemical analyses included measuring total polypeptide degradation, electrophoretic profiles and low-molecular weight polypeptide concentrations to elucidate their involvement in the wear process. The effects of the various calf sera constituent fractions on microbial growth were also explored. The polyethylene wear rates and the results from the biochemical analyses for the three calf serum lubricants were all found to be statistically significantly different from each other. The lubricant derived from the alpha-calf serum was closest in constituent fractions to human synovial fluid. It also showed the lowest polyethylene wear rate (14.38 +/- 0.85 mm3/million cycles) and the lowest amount of polypeptide degradation (7.77 +/- 3.87%). Furthermore, the alpha-calf serum lubricant was associated with the least amount of change in the electrophoretic profile, the least change in low-molecular weight polypeptide concentration, and the lowest microbial growth in the presence of sodium azide (a microbial inhibitor conventionally used in implant wear testing). Replacing sodium azide with a broad spectrum antibiotic-antimycotic eradicated the microbial growth. Some speculation was entertained regarding the effect of alpha-calf serum on colloid-mediated boundary lubrication. Based on the results, it was recommended that ISO 14243-3 be modified to include guidelines on calf serum constituent fractions that would favour using alpha-calf serum in order to improve the fidelity of the simulation in knee implant wear testing.

Medical decision-making among Hispanics and non-Hispanic Whites with chronic back and knee pain: a qualitative study.

BACKGROUND: Musculoskeletal disorders affect all racial and ethnic groups, including Hispanics. Because these disorders are not life-threatening, decision-making is generally preference-based. Little is known about whether Hispanics in the U.S. differ from non-Hispanic Whites with respect to key decision making preferences. METHODS: We assembled six focus groups of Hispanic and non-Hispanic White patients with chronic back or knee pain at an urban medical center to discuss management of their conditions and the roles they preferred in medical decision-making. Hispanic groups were further stratified by socioeconomic status, using neighborhood characteristics as proxy measures. Discussions were led by a moderator, taped, transcribed and analyzed using a grounded theory approach. RESULTS: The analysis revealed ethnic differences in several areas pertinent to medical decision-making. Specifically, Hispanic participants were more likely to permit their physician to take the predominant role in making health decisions. Also, Hispanics of lower socioeconomic status generally preferred to use non-internet sources of health information to make medical decisions and to rely on advice obtained by word of mouth. Hispanics emphasized the role of faith and religion in coping with musculoskeletal disability. The analysis also revealed broad areas of concordance across ethnic strata including the primary role that pain and achieving pain relief play in patients' experiences and decisions. CONCLUSIONS: These findings suggest differences between Hispanics and non-Hispanic Whites in preferred information sources and decision-making roles. These findings are hypothesis-generating. If confirmed in further research, they may inform the development of interventions to enhance preference-based decision-making among Hispanics.

Commissioning of a displacement-controlled knee wear simulator and exploration of some issues related to the lubricant.

A six-station displacement-controlled knee simulator with separately controlled left (L) and right (R) banks (three wear implants per bank) was commissioned for a total of three million cycles (Mc) following ISO 14243-3. A commissioning protocol was applied to compare the polyethylene wear among the six wear stations by exchanging the implants between wear stations. Changes in lubricant characteristics during wear testing, such as polypeptide degradation, low-molecular-weight polypeptide concentration, and possible microbial contamination were also assessed. The total mean wear rate for the implants was 23.60 +/- 1.96 mm3/Mc and this was of a similar magnitude to the mean wear rate for the same implant tested under similar conditions by DePuy Orthopaedics Inc. (Warsaw, IN). Repeated run-in wear was observed when the implants were exchanged between wear stations, suggesting that implants should be subjected to the same wear station throughout the duration of a wear test. The total polypeptide degradation for the implants measured 30.53 +/- 3.96 percent; the low-molecular-weight polypeptide concentration of the "used" lubricant for implants (0.131 +/- 0.012 g/L) was 3.3 times greater than the mean polypeptide concentration of the fresh, "unused" lubricant (0.039 +/- 0.004 g/L). This increase in low-molecular weight polypeptide concentration was suggested to be attributable to protein shear in the articulation of the implant, the circulation of the lubricant, and some proteolytic activity. Sodium azide was ineffective in maintaining a sterile environment for wear testing as a single, highly motile Gram-negative micro-organism was identified in the lubricant from wear tests.

Foam Rolling and Muscle and Joint Proprioception After Exercise-Induced Muscle Damage.

CONTEXT: Foam rolling (FR) is considered an effective postexercise modality for reducing delayed-onset muscle soreness and enhancing recovery of muscle function. However, the effects of FR on muscle and joint proprioception have not been investigated. OBJECTIVE: To examine the effects of FR on muscle and joint proprioception after an intense exercise protocol. DESIGN: Controlled laboratory study. SETTING: University-based laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 80 healthy, physically active male students were randomly assigned to either the FR (n = 40; age = 22.8 ± 3.3 years, height = 176.4 ± 5.3 cm, mass = 74.2 ± 6.4 kg) or passive-recovery (PR; n = 40; age = 23.0 ± 3.2 years, height = 178.1 ± 5.5 cm, mass = 74.6 ± 6.2 kg) group. INTERVENTION(S): Participants in both groups performed 4 sets of 25 repetitions of voluntary maximal eccentric contractions at 60°/s from 20° to 100° of knee flexion to induce exercise-induced muscle damage. The exercise was followed by either PR or 2 minutes of FR immediately (1 hour) and 24, 48, and 72 hours postexercise. MAIN OUTCOME MEASURE(S): Muscle soreness, pressure-pain threshold, quadriceps-muscle strength, joint position sense, isometric force sense, and threshold to detect passive movement at baseline and immediately, 24, 48, and 72 hours postexercise after FR. RESULTS: Foam rolling resulted in decreased muscle pain, increased pressure-pain threshold, improved joint position sense, attenuated force loss, and reduced threshold to detect passive movement compared with PR at 24 and 48 hours postexercise. CONCLUSIONS: Foam rolling postexercise diminished delayed-onset muscle soreness and improved recovery of muscle strength and joint proprioception. These results suggested that FR enhanced recovery from exercise-induced damage.

The effect of tourniquet usage on cement penetration in total knee arthroplasty: A prospective randomized study of 3 methods.

BACKGROUND: It is a randomized study to compare cement penetration on x-rays after total knee arthroplasty (TKA) among 3 different ways to use tourniquets; application during the surgery, application only with implantation prosthesis and with no tourniquet use. METHODS: A total 69 knees of 59 patients were included in the study in a quasirandom manner. Each patient had physical exams and standard radiographic evaluations at 6 weeks after the TKA procedure. Outcome evaluations included visual analog scale (VAS) scores, Knee Society Scores (KSS), blood transfusion, and drainage status after surgery for all groups. For radiographic review, the tibial plateau was divided into zones in the anterior-posterior and lateral views, according to the Knee Society Scoring System. RESULTS: The average age of the patients who were eligible for the study was 65.05 (range 46-81) years. All 59 patients included in the study were female patients. Group 1 consisted of 24 patients who had TKA with use of a tourniquet during the entire operation. Group 2 consisted of 20 patients who had TKA with use of tourniquet only at the time of cementing and group 3 consisted of 25 patients with no use tourniquet. There is no significant difference in early cement penetration among the groups (group 1 2.50 mm, group 2 2.28 mm, group 3 2.27 mm; group 1 vs 2 P = .083, group 1 vs 3 P = .091, group 2 vs 3 P = .073). There is no significant difference for postoperative drainage among the 3 groups (group 1 245 mL, group 2 258.76 mL, group 3 175.88 mL; group 1 vs 2 P = .081, group 1 vs 3 P = .072, group 2 vs 3 P = .054). There was no need to transfuse more than 1 unit in any patient. The VAS score was significantly higher (group 1 3.58, group 2 1.55, group 3 1.52; group 1 vs 2 P = .022, group 1 vs 3 P = .018, group 2 vs 3 P = .062) and KSS was significantly lower in the tourniquet group (group 1 63, group 2 79, group 3 82; group 1 vs 2 P = .017, group 1 vs 3 P = .02, group 2 vs 3 P = .082). CONCLUSION: We do not suggest long-duration tourniquet use, which can lead higher pain scores and reduce functional recovery after total knee arthroplasty.

The characteristics of gait in Charcot-Marie-Tooth disease types I and II.

Certain typical gait characteristics such as foot-drop and foot supination are well described in Charcot-Marie-Tooth disease. These are directly related to the primary disease and due to the weakness of ankle dorsiflexors and everters characteristic of this hereditary neuropathy. We analysed 16 subjects aged 8-52 years old (11 with type I, 5 with type II Charcot-Marie-Tooth disease) using three-dimensional gait analysis and identified kinematic features previously unreported. These patients showed a combination of tight tendo achillei, foot-drop, failure of plantar flexion and increased foot supination, but also presented with excessive internal rotation of the knee and/or tibia, knee hyperextension in stance, excessive external rotation at the hips and decreased hip adduction in stance (typical of a broad based gait). These proximal features could have been an adaptation to or consequence of the disrupted ankle and foot biomechanics, however a direct relation to the neuropathy is also possible since sub-normal muscle power was observed at the proximal levels in most subjects on both manual testing and kinetic analysis. Gait analysis is a useful tool in defining the characteristic gait of patients with Charcot-Marie-Tooth disease.

M. biceps femoris - A wolf in sheep's clothing: The downside of a lower limb injury prevention training.

Both, hamstring and ACL injuries are among the most typical injuries, particularly in change of direction and high speed running sports. They're also difficult to treat. Therefore, in the past few years, sports medicine practitioners and exercise scientists have mainly been focusing on the development and implementation of preventive programs in order to reduce the number of lower limb injuries, mainly by improving knee alignment. A number of studies have been able to prove the success of these training interventions, which are mainly addressing sensorimotor abilities and plyometric activities. The number of non-contact hamstring injuries has nevertheless been on the rise, particularly in sports like soccer and football. Therefore, the purpose of the following article is to introduce the hypothesis that the above-mentioned training interventions have a massive influence on the activation patterns on the targeted muscle group, and on the M. biceps femoris in particular. Muscle function and the resulting internal load are directly related to muscle architecture at the insertion. Training induced adaptations in hamstring activation patterns can thus lead to an increased injury susceptibility. In this case, a simulation model that directly relates to an acute deceleration maneuver provides valuable insights into the function of the biceps femoris muscle, especially when the rate of activity and the muscle geometry at the insertion area are taken into consideration. We conclude that there needs to be a greater individualization of prevention programs, especially in regards to anatomical requirements, in order to further reduce injury rates in elite sports. Moreover, it would also seem reasonable to apply a similar approach to aspects of chronic pain such as chronic non-specific low back pain.

Fluid composition impacts standardized testing protocols in ultrahigh molecular weight polyethylene knee wear testing.

Wear of total knee replacements is determined gravimetrically in simulator studies. A mix of bovine serum, distilled water, and additives is intended to replicate the lubrication conditions in vivo. Weight gain due to fluid absorption during testing is corrected using a load soak station. In this study, three sets of ultrahigh molecular weight polyethylene tibial plateau were tested against highly polished titanium condyles. Test 1 was performed in two different institutions on the same simulator according to the standard ISO 14243-1, using two testing lubricants. Test 2 and test 3 repeated both previous test sections. The wear and load soak rates changed significantly with the lubricant. The wear rate decreased from 16.9 to 7.9 mg weight loss per million cycles when switching from fluid A to fluid B. The weight gain of the load soak specimen submersed in fluid A was 6.1 mg after 5 x 10(6) cycles, compared with 31.6 mg for the implant in fluid B after the same time period. Both lubricants were mixed in accordance with ISO 14243 (Implants for surgery - wear of total knee-joint prostheses), suggesting that calf serum should be diluted to 25 +/- 2 per cent with deionized water and a protein mass concentration of not less than 17 g/l. The main differences were the type and amount of additives that chemically stabilize the lubricant throughout the test. The results suggest that wear rates can only be compared if exactly the same testing conditions are applied. An agreement on detailed lubricant specifications is desirable.

The Gore-Tex anterior cruciate ligament prosthesis. Two versus three year results.

A prospective clinical study of the results of prosthetic ligament replacement of the ACL with the Gore-Tex polytetrafluoroethylene prosthesis was undertaken. Thirty-three (80%) of 41 patients were available at a minimum 36 month followup (mean, 48 months; range, 36 to 62). Kaplan-Meier survival analysis revealed an 82% probability of survival of the polytetrafluoroethylene ligament at the 48 month followup. When compared to the same data at a minimum 24 month followup, the results appeared to have deteriorated somewhat over time. Three possible "predictors" of failure at later followup were identified: preoperative subjective symptoms of swelling, subjective symptoms of giving way at 2 years, and an increased anterior drawer sign at 2 years.

Femoral plating.

We have demonstrated that we are able to meet both trauma and orthopedic goals with immediate plate fixation of femoral fractures in patients with blunt polytrauma. Our femoral fracture mortality rate is less than our predicted institutional mortality rate of patients with comparative injury severity scores. Ipsilateral femoral neck and shaft fractures are easily repaired with femoral plating. Infections, even in open fractures and systemically unstable patients, are rare. Implant failures have been infrequent and are easily reconstructed with intramedullary nails. Knee motion has been restored reliably. Stainless steel DCP plate fixation requires primary bone grafting. Achieving union and subsequent knee rehabilitation often requires that patients remain on crutches for up to 6 months. Our experience with titanium LCDCP plates is preliminary, but we are seeing a significant amount of callus formation and, perhaps, earlier union and bearing weight.

Effect of stair descent loading on ultra-high molecular weight polyethylene wear in a force-controlled knee simulator.

A loading protocol approximating forces, torques and motions at the knee during stair descent was developed from previously published data for input into a force-controlled knee simulator. A set of total knee replacements (TKRs) was subjected to standard walking cycles and stair descent cycles at a ratio of 70: 1 for 5 million cycles. Another set of implants with similar articular geometry and the same ultra-high molecular weight polyethylene (UHMWPE) resin (GUR 415), sterilization and packaging was tested with standard walking cycles only. Implant kinematics, gravimetric wear and surface roughness of the UHMWPE inserts were analysed for both sets of implants. Contact stresses were calculated for both loading protocols using a Hertzian line contact model. Significantly greater weight loss (p < 0.05) and more severe surface damage of UHMWPE inserts resulted with the walking + stair descent loading protocol compared to walking cycles only. Anterior-posterior (AP) tibiofemoral contact point displacements were lower during stair descent than walking, but not significantly different (p = 0.05). Contact stresses were significantly higher during stair descent than walking, owing to higher axial loads and the smaller radius of curvature of the femoral components at higher flexion angles. High contact stresses on UHMWPE components are likely to accelerate the fatigue of the material, resulting in more severe wear, similar to what is observed in retrieved implants. Thus the inclusion of loading protocols for activities of daily living in addition to walking is warranted for more realistic in vitro testing of TKRs.

Altered knee and ankle kinematics during squatting in those with limited weight-bearing-lunge ankle-dorsiflexion range of motion.

CONTEXT: Ankle-dorsiflexion (DF) range of motion (ROM) may influence movement variables that are known to affect anterior cruciate ligament loading, such as knee valgus and knee flexion. To our knowledge, researchers have not studied individuals with limited or normal ankle DF-ROM to investigate the relationship between those factors and the lower extremity movement patterns associated with anterior cruciate ligament injury. OBJECTIVE: To determine, using 2 different measurement techniques, whether knee- and ankle-joint kinematics differ between participants with limited and normal ankle DF-ROM. DESIGN: Cross-sectional study. SETTING: Sports medicine research laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty physically active adults (20 with limited ankle DF-ROM, 20 with normal ankle DF-ROM). MAIN OUTCOME MEASURE(S): Ankle DF-ROM was assessed using 2 techniques: (1) nonweight-bearing ankle DF-ROM with the knee straight, and (2) weight-bearing lunge (WBL). Knee flexion, knee valgus-varus, knee internal-external rotation, and ankle DF displacements were assessed during the overhead-squat, single-legged squat, and jump-landing tasks. Separate 1-way analyses of variance were performed to determine whether differences in knee- and ankle-joint kinematics existed between the normal and limited groups for each assessment. RESULTS: We observed no differences between the normal and limited groups when classifying groups based on nonweight-bearing passive-ankle DF-ROM. However, individuals with greater ankle DF-ROM during the WBL displayed greater knee-flexion and ankle-DF displacement and peak knee flexion during the overhead-squat and single-legged squat tasks. In addition, those individuals also demonstrated greater knee-varus displacement during the single-legged squat. CONCLUSIONS: Greater ankle DF-ROM assessed during the WBL was associated with greater knee-flexion and ankle-DF displacement during both squatting tasks as well as greater knee-varus displacement during the single-legged squat. Assessment of ankle DF-ROM using the WBL provided important insight into compensatory movement patterns during squatting, whereas nonweight-bearing passive ankle DF-ROM did not. Improving ankle DF-ROM during the WBL may be an important intervention for altering high-risk movement patterns commonly associated with noncontact anterior cruciate ligament injury.

A multilayer braided scaffold for Anterior Cruciate Ligament: mechanical modeling at the fiber scale.

An adapted scaffold for Anterior Cruciate Ligament (ACL) tissue engineering must match biological, morphological and biomechanical requirements. Computer-aided tissue engineering consists of finding the most appropriate scaffold regarding a specific application by using numerical tools. In the present study, the biomechanical behavior of a new multilayer braided scaffold adapted to computer-aided tissue engineering is computed by using a dedicated Finite Element (FE) code. Among different copoly(lactic acid-co-(ε-caprolactone)) (PLCL) fibers tested in the present study, PLCL fibers with a lactic acid/ε-caprolactone ratio of 85/15 were selected as a constitutive material for the scaffold considering its strength and deformability. The mechanical behavior of these fibers was utilized as material input in a Finite Element (FE) code which considers contact/friction interactions between fibers within a large deformation framework. An initial geometry issued from the braiding process was then computed and was found to be representative of the actual scaffold geometry. Comparisons between simulated tensile tests and experimental data show that the method enables to predict the tensile response of the multilayer braided scaffold as a function of different process parameters. As a result, the present approach constitutes a valuable tool in order to determine the configuration which best fits the biomechanical requirements needed to restore the knee function during the rehabilitation period. The developed approach also allows the mechanical stimuli due to external loading to be quantified, and will be used to perform further mechanobiological analyses of the scaffold under dynamic culture.

Freeman-Sheldon syndrome--prenatal and postnatal diagnosis.

A six-day-old girl, born to normal non-consanguineous parents presented with mask like facies with a small mouth giving a 'whistling' appearance. Other dysmorphic features include deep set eyes, broad nasal bridge, long philtrum and 'H' shaped cutaneous dimple on the chin. There was congenital windmill vane hand position and severe talipes equinovarus deformity. The above features are characteristic of Freeman-Sheldon syndrome also known as Whistling Face syndrome. Ultrasound scanning during 8(th) month of the pregnancy showed the fetus to have facial abnormality and bilateral clenched hand and talipes with extension contractures of knees. Provisional diagnosis of FSS was made which was confirmed after the birth. Thus all cases of Arthrogryposis during prenatal scan should be carefully looked for the facial abnormality in the fetus.

Calcium phosphate cement augmentation in the treatment of depressed tibial plateau fractures with open reduction and internal fixation.

OBJECTIVES: We aimed to evaluate the clinical and radiological outcomes of open reduction and internal fixation augmented with calcium phosphate cement (CPC) in the treatment of depressed tibial plateau fractures. METHODS: Twenty-eight knees of 28 patients [19 males and 9 females; mean age, 41.2 years (range 22-72 years)] who had open reduction and internal fixation combined with CPC augmentation were included in this study. Seventeen fractures were Schatzker type II, 5 were type III, 3 were type IV, 2 were type V, and 1 was type VI. CPC was used to fill the subchondral bone defects in all knees. Fixation of the fragments was done with screws in 3 knees (10%). Standard proximal tibial plates or buttress plates were used in 25 knees (90%) with an additional split fragment extending distally to achieve internal fixation. Full weight-bearing was allowed in 6.4 weeks (range 6-12 weeks) after surgery. Resorption of CPC granules was defined as the decrease in the size and density of grafting material on radiographs. Rasmussen's radiological and clinical scores were determined postoperatively. Functionality was assessed with Lysholm knee scoring system. Activity was graded with Tegner's activity scale. RESULTS: Union was achieved in all patients with a mean follow-up of 22.2 months (range 6-36 months). There were no intraoperative complications. At the latest follow-up radiographs, resorption of the graft was observed in 25 knees (89%). Rasmussen's radiologic score was excellent in 17 patients (61%), good in 9 patients (32%), and fair in 2 patients (7%). Rasmussen's clinical score was excellent in 9 patients (32%), good in 18 patients (64%), and fair in 1 patient (4%). According to the Lysholm knee score, functional results were excellent in 16 patients (57%), good in 8 patients (29%), and fair in 4 patients (14%). Twenty-two patients (78%) achieved the preoperative activity level after surgery, and there was no significant difference between the mean preoperative and postoperative Tegner scores (4.11±0.68 and 4.04±0.64, respectively, p=0.161). CONCLUSION: CPC is a safe biomaterial with many advantages in augmenting the open reduction and internal fixation of depressed tibial plateau fractures, including elimination of morbidity associated with bone graft harvesting, the unlimited supply of bone substitute, the optimum filling of irregular bone defects, and shortening of the postoperative full weight-bearing time.

An in vivo biomechanical analysis of the soft-tissue envelope of osteoarthritic knees.

Soft-tissue balancing and the amount of tension applied to the ligaments in a well-functioning total knee arthroplasty (TKA) has, thus far, not been accurately quantified. A ligament-tensioning device was used to measure displacement between the tibia and femur versus load during 86 consecutive TKAs. Measurements were made in flexion and extension following bone cuts and final soft-tissue balancing to calculate mean effective stiffness (MES) of the soft-tissue envelope and mean resting force on the implanted polyethylene component. MES was not affected by age or gender and did not differ in flexion versus extension. MES was significantly higher in posterior cruciate-retaining knees compared with posterior cruciate-sacrificing knees. There was no statistical difference between mean resting force on the polyethylene in flexion versus extension, or in posterior cruciate-retaining versus -sacrificing knees. These biomechanical data will serve as a good starting point for which to compare the expected stiffness of the ligaments and resting load on the polyethylene in well-balanced knees.

Evaluation of silicone as an artificial lubricant in osteoarthrotic joints.

Silicone 300 has been evaluated as an artificial lubricant in osteoarthrotic joints by means of a pilot study in five inpatients and a control trial of 25 outpatients with 40 osteoarthrotic knees. Sequential analysis showed a significant benefit from saline compared with silicone at one week follow-up and no significant difference at one month.Measurement of stiffness with a knee arthrograph showed no difference in reduction of stiffness between the two substances. In a study of 18 rabbits there was no evidence that silicone was retained in the joint cavity for longer than 48 hours. There was a failure of clearance of iodinated serum albumin for as long as three to four days after the injection of silicone, suggesting some obstruction to lymphatic outflow. Experimentally produced cartilaginous defects did not heal quicker with the injection of silicone into the joint.

Immediate skin expansion: an old concept by a novel and inexpensive technique.

Intraoperative skin expansion is not a new concept. We have developed a technique using readily available inexpensive material to achieve wound closure. In this prospective study, 15 patients (age range, 1-72 years) with melanoma, giant nevi, scars, meningocele, gastroschisis, alopecia, thrombosed renal dialysis fistula, calcified nodule and trauma, with defects on back, limbs, abdomen, scalp, hand, calcaneum, and sole of foot were treated. Only hypodermic needles and dental wire, with an overall cost of less than a dollar, are needed for the immediate skin expansion technique. In contrast, the numerous other commercial devices currently in use are costly and must be ordered in advance. Using our technique, the wound can be gradually approximated and subcutaneous sutures placed with the device in situ. An intradermal or simple running suture is then placed to approximate the skin edges under little or no tension and the device is removed. All patients had a good result with minimal morbidity. The wounds treated by this technique healed by primary intention except in 3 patients, who developed minor dehiscence of the wounds.