PubMed Health⌕ Search

PubMed · 16843157

Both-bone forearm osteotomy for supination contracture: a cadaver model.

Abstract

PURPOSE: To quantify the magnitude of rotational correction possible when comparing a single forearm bone osteotomy and fixation with stepwise osteotomy and fixation of both bones in a cadaver model and to determine if the order in which the stepwise osteotomies are performed influences the amount of correction. METHODS: Ten fresh-frozen cadaveric forearms were fixed to a frame positioned in the field of view of a motion-capture system. An experimental supination contracture was induced in full supination. Cadaver forearms were assigned randomly to group I (ulna osteotomy, rotation, plating) or group II (radius osteotomy, rotation, plating). Cadavers in group I were used later in group III (ulna + radius) by completing a radial osteotomy, rotation, and fixation in the forearms with the plated ulna. Similarly the specimens assigned to group II were used later in group IV (radius + ulna) by completing an ulna osteotomy, rotation, and fixation in the forearms with the plated radiuses. Measurements of forearm pronation were made after single-bone (groups I, II) and stepwise both-bone (groups III, IV) rotational osteotomies. RESULTS: Stepwise rotational osteotomy and fixation of the ulna followed by the radius produced significantly more corrective pronation (101 degrees) than rotating the radius followed by the ulna (65 degrees). Rotating the radius gave only moderate correction (58 degrees) and minimal correction was produced by ulna osteotomy alone (15 degrees). CONCLUSIONS: Rotational osteotomy of both forearm bones can create approximately 100 degrees of correction when performed at the proximal ulna followed by the distal radius. If less rotation is needed then the distal radius osteotomy alone can provide approximately 60 degrees of correction.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Douglas T Hutchinson, Angela A Wang, Daniel Ryssman, Nicholas A T Brown. Both-bone forearm osteotomy for supination contracture: a cadaver model.. https://doi.org/10.1016/j.jhsa.2006.01.010

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The effect of excessive tibial torsion on the capacity of muscles to extend the hip and knee during single-limb stance.

Excessive tibial torsion, a rotational deformity about the long axis of the tibia, is common in patients with cerebral palsy who walk with a crouch gait. Previous research suggests that this deformity may contribute to crouch gait by reducing the capacity of soleus to extend the knee; however, the effects of excess external torsion on the capacity of other muscles to extend the stance limb during walking are unknown. A computer model of the musculoskeletal system was developed to simulate a range of tibial torsion deformities. A dynamic analysis was then performed to determine the effect of these deformities on the capacity of lower limb muscles to extend the hip and knee at body positions corresponding to the single-limb stance phase of a normal gait cycle. Analysis of the model confirmed that excessive external torsion reduces the extension capacity of soleus. In addition, our analysis revealed that several important muscles crossing the hip and knee are also adversely affected by excessive tibial torsion. With a tibial torsion deformity of 30 degrees , the capacities of soleus, posterior gluteus medius, and gluteus maximus to extend both the hip and knee were all reduced by over 10%. Since a tibial torsion deformity reduces the capacity of muscles to extend the hip and knee, it may be a significant contributor to crouch gait, especially when greater than 30 degrees from normal, and thus should be considered by clinicians when making treatment decisions.

Biomechanical Phenomena↗

Predicting the subject-specific primary stability of cementless implants during pre-operative planning: preliminary validation of subject-specific finite-element models.

Pre-operative planning help the surgeon in taking the proper clinical decision. The ultimate goal of this work is to develop numerical models that allow the surgeon to estimate the primary stability during the pre-operative planning session. The present study was aimed to validate finite-element (FE) models accounting for patient and prosthetic size and position as planned by the surgeon. For this purpose, the FE model of a cadaveric femur was generated starting from the CT scan and the anatomical position of a cementless stem derived by a skilled surgeon using a pre-operative CT-based planning simulation software. In-vitro experimental measurements were used as benchmark problem to validate the bone-implant relative micromotions predicted by the patient-specific FE model. A maximum torque in internal rotation of 11.4 Nm was applied to the proximal part of the hip stem. The error on the maximum predicted micromotion was 12% of the peak micromotion measured experimentally. The average error over the entire range of applied torques was only 7% of peak measurement. Hence, the present study confirms that it is possible to accurately predict the level of primary stability achieved for cementless stems using numerical models that account for patient specificity and surgical variability.

Biomechanical Phenomena↗

Experimental validation of intact and implanted distal femur finite element models.

Four finite element (FE) models of intact and distal femur of knee replacements were validated relative to measured bone strains. FE models of linear tetrahedrons were used. Femoral replacements with cemented stemless, cemented and noncemented femoral stems of the PFC Sigma Modular Knee System were analyzed. Bone strains were recorded at ten locations on the cortex. The magnitude of the FE bone strains corresponded to the mean measured strains, with an overall agreement of 10%. Linear regression between the FE and mean experimental strains produced slopes between 0.94 and 1.06 and R(2) values between 0.92 and 0.99. RSME values were less than 12%. The FE models were able to adequately replicate the mechanical behavior of distal femur reconstructions.

Biomechanical Phenomena↗