L-shaped caliper for limb length measurement during total hip arthroplasty.

The existing methods of assessing limb lengthening during total hip arthroplasty (THA) are prone to error because the measurements are not parallel to the limb lengthening axis. In order to address this, we designed a caliper to estimate limb lengthening during THA and evaluated its accuracy compared with our previous device, the straight caliper. Limb lengths were measured in 100 patients. The L-shaped caliper was used in 50 cases and the straight caliper in 50. The correlation between intra-operative and post-operative radiographic measurements was significantly improved using the L-shaped device (p < 0.0001, r = 0.934). This method was extremely accurate in predicting changes in limb length due to surgery.

Hygiene problems of residual limb and silicone liners in transtibial amputees wearing the total surface bearing socket.

OBJECTIVE: To determine whether washing the residual limb and silicone liner reduces the associated skin problems in transtibial amputees who wear a total surface bearing (TSB) socket. DESIGN: Case series. SETTING: General community. PATIENTS: Eighty-three transtibial amputees (65 men, 18 women; mean age, 53.4 yr) in western Japan who used or had used a TSB socket with a silicone liner in the previous 5 years. INTERVENTION: Participants took a self-administered questionnaire that included items concerning their personal profile, daily life activities, period of TSB use (yr), hours of TSB use daily, washing frequency of the residual limb and silicone liner, the method of washing, and any associated hygiene problems. MAIN OUTCOME MEASURES: Logistic regression analysis was applied to examine factors related to hygiene problems. Predicted values include hygiene problems (perspiration, eruptions, itching, odor) and explanatory values include TSB use, daily life activity, and washing of limb and prosthetic. RESULTS: Fifty-five subjects washed the residual limb, and 44 subjects washed the silicone liner every day. Itching, perspiration, eruption, and odor were frequent hygiene problems. Perspiration was noted less by women, eruption more by older subjects, and itching and odor more by younger subjects. Washing the silicone liner every day was associated with fewer reports of skin eruption. CONCLUSION: Keeping the residual limb and silicone liner clean is important to reduce skin problems, but hygiene problems of the residual limb and silicone liner still remain to be resolved.

Moisture permeability of the total surface bearing prosthetic socket with a silicone liner: is it superior to the patella-tendon bearing prosthetic socket?

The purpose of this study was to examine the moisture permeability properties of materials used for total surface bearing (TSB) socket with a silicone liner, a combination of Silicone Suction Socket or Icelandic Roll-On Silicone Socket (ICEROSS) and an acrylic plastic sheet (Degaplast), patella-tendon bearing (PTB) socket, a combination of Pe-Lite and Degaplast, and wooden socket made of poplar. Moisture permeability of the socket materials was measured as the diminution of water in a container after 12 hours in a climatic chamber. Eight containers with their open, top side were uncovered (no material) or sealed with one of the socket materials; the experiment was repeated four times. One-way analysis of variance followed by Bonferroni's test was applied to examine the differences in moisture permeability. Moisture permeability levels were as follows: no material, 85.9 +/- 1.3 g; poplar, 4.3 +/- 0.4 g; Silicone Suction Socket, 1.1 +/- 0.2 g; ICEROSS, 1.0 +/- 0.2 g; Pe-Lite, 0.8 +/- 0.1 g; 3S + Degaplast, 0.8 +/- 0.1 g; ICEROSS + Degaplast, 0.8 +/- 0.2 g; and Pe-Lite + Degaplast, 0.8 +/- 0.1 g. There were significant differences between the uncovered container and the others, and between poplar and the others (P < 0.05). We concluded that the TSB socket with a silicone liner is not superior to the PTB socket with regard to moisture permeability, and that it is necessary to develop a new prosthetic socket that allows heat release and drainage of sweat.

Total surface bearing below-knee prosthesis: advantages, disadvantages, and clinical implications.

OBJECTIVE: To investigate the total surface bearing (TSB) prosthesis for below-knee amputee patients and to determine its clinical indications. DESIGN: Case series. SETTING: University hospital and the Welfare Center for the Disabled. PATIENTS: Thirty-two subjects who could walk with the TSB prosthesis and had already used the patellar-tendon bearing (or Kondylen-Bettung Münster) socket. MAIN OUTCOME MEASURE: Subjective assessment of the TSB socket, consisting of an overall rating and ratings of 13 individual items, was performed, and results were analyzed with Fisher's exact test. RESULTS: Seventy-five percent of the subjects were satisfied overall with the TSB socket. Of the 13 items, comfort, ease to swing, pain, piston movement, tightness, skin irritation, appearance, and durability were regarded as good by more than 75% of the patients. Donning, perspiration, odor, and staining were regarded as poor by more than 20%. Items that were significantly related with overall satisfaction with the TSB socket were comfort, ease to swing, and piston movement, while donning was significantly related to dissatisfaction. CONCLUSION: The TSB socket is suitable for and preferred by many amputee subjects, but some problems remain to be solved.

Properties of the flexible pressure sensor under laboratory conditions simulating the internal environment of the total surface bearing socket.

The purpose of this study was to investigate the properties of the flexible pressure sensor under laboratory conditions simulating the internal environment of the total surface bearing (TSB) socket to determine optimal conditions for measuring normal stresses on the stump. The equipment used in the study was the Pressure Distribution Sensor System for Sockets. In a climatic chamber maintained at 37 degrees C and 70% humidity the sensor sheet was mounted on a measuring apparatus loaded with three 10 kg weights, and output from the sensor was recorded. Because of sensor creep, a sample 60 seconds after loading was adopted as the measured output. Output was greater when weight was decreased than when weight was increased because of hysteresis (paired t-test, p<0.05). The sensor had temperature sensitivity but differences in output were not statistically significant (paired t-test, 0.10>p>0.05). There were no significant differences in output among five sensor sheets or among five sections of four sensor sheets (two-way ANOVA, p>0.05), but repeated loading on the same section of the sensor sheet increased output (two-way ANOVA, p<0.05). Reproducibility and sensitivity distribution of the sensor are considered satisfactory under laboratory conditions, but measurements of rapid and repetitive movements may not be accurate and comparing subtle changes in output from a single sensor is not suitable. The reliability of the sensor in a clinical setting for measuring normal stresses on the stump with the TSB socket should be examined.