Norris C. Carroll

Transfer of the rectus femoris: Effects of transfer site on moment arms about the knee and hip

Decreased range of knee motion during gait is often treated by surgically releasing the rectus femoris from the patella and transferring it to one of four sites: semitendinosus, gracilis, sartorius, or the iliotibial tract. This study was conducted to determine if there are differences between these four tendon transfer sites in terms of post-surgical moment arms about the knee and hip. A graphics-based model of the lower extremity was used to simulate the origin-to-insertion path of the rectus femoris after transfer. Anatomical studies were conducted to evaluate the accuracy of the simulated tendon transfers by comparing knee flexion moment arms calculated with the computer model to moment arms measured in two anatomical specimens. The computer simulations and anatomical studies revealed substantial differences in the knee moment arms between the four sites. We found that the rectus femoris has the largest peak knee flexion moment arm (4-5 cm) after transfer to the semitendinosus. In contrast, after transfer to the iliotibial tract the rectus femoris has a slight (0-5 mm) knee extension moment arm. None of the transfers to muscle-tendon complexes on the medial side of the knee (semitendinosus, gracilis, sartorius) substantially affect the hip rotation moment arm of the rectus femoris. Transferring to the iliotibial tract increases hip internal rotation moment arm of the rectus femoris, but only when the hip is externally rotated.

Femoral shaft fractures in children treated with early spica cast.

We retrospectively reviewed 51 patients aged 3–11 years with femoral shaft fractures selected for treatment with early spica cast immobilization. Shortening > 20 mm was the most common complication, occurring in 22 (43%) of the 51 patients. Factors associated with unacceptable shortening were shortening at the time of spica cast application > 10 mm, shortening > 20 mm at initial examination, and increasing age. Achieving < 1 cm shortening at the time of cast application and close follow-up during the first 2 weeks after cast application are advised in order to achieve an acceptable final outcome.

Analysis of the Components of Residual Deformity in Clubfeet Presenting for Reoperation

We reviewed the records and radiographs of 125 children with 159 clubfeet reoperated for residual deformity after operative repair (210 reoperations). We concluded that residual forefoot adduction and supination were the most common persistent deformities (present in 95% of the feet) and that these deformities resulted from undercorrection at the time of primary operation. Although not then apparent, the persistent deformities became more evident with growth, and additional treatment became necessary. Undercorrection resulted from not releasing the calcaneocuboid joint and plantar fascia and failure to recognize residual forefoot adduction on the interaoperative radiographs at primary operation.

Clubfoot analysis with three-dimensional computer modeling.

Which way are the bones rotated in a club-foot? This question has long been debated by clubfoot surgeons. Opinions have been based on observations from surgery, radiographs, and autopsies. These methods all have pitfalls and are subject to misinterpretation. We used three-dimensional computer modeling to analyze histologic sections of a newborn clubfoot and a newborn normal foot. Relative to the bimalleolar axis in the axial plane, the normal talus demonstrated 5° of internal rotation of its body and 25° internal rotation of its neck. The clubfoot talus showed 14° of external rotation of its body and 45° of internal rotation of its neck. The calcaneus was externally rotated 5° in the normal foot and internally rotated 22° in the clubfoot.

Femoral varus derotation osteotomy with or without acetabuloplasty for unstable hips in cerebral palsy

We reviewed 39 children with cerebral palsy who had surgery for hip subluxation or dislocation. Of 55 treated hips, 31 had a varus derotation osteotomy alone, and 24 had a combination of varus derotation osteotomy and an acetabular procedure. There was no significant difference in the ages of the two groups. There was no difference in the preoperative acetabular indices of the two groups, but the average percentage of preoperative uncoverage of the femoral head was 56% in the group with varus derotation osteotomy and 63% in the group with combined varus derotation osteotomy with an acetabular procedure. The incidence of resubluxation or redislocation (24%) after varus derotation osteotomy alone was higher than that after varus derotation osteotomy with an acetabular procedure (13%). The incidence of postoperative hip instability was higher in the patients who had preoperative uncoverage of the femoral head ranging from 70 to 100%. This was in comparison with the patients who had preoperative uncoverage of the femoral head ranging from 30 to 70%. These results suggest that a combination of varus derotation osteotomy and an acetabular procedure decreases the incidence of resubluxation or redislocation, and that unstable hips with > 70% uncoverage of the femoral head should undergo the combined procedure.

Hip stability and ambulatory status in myelomeningocele.

Fifty-three hips in 32 patients with myelomeningocele and innervation to the quadriceps were surgically stabilized. In most cases, all the surgical procedures necessary to achieve stability were performed at the same time. Preoperatively, 92.5% of the hips were either subluxated or dislocated; the rest were dysplastic. At the time of review, an average of 4 years 1 month following surgery, 83% of the hips were stable. Of the children, 78% were community ambulators. Ambulatory status was found to be adversely affected by subsequent development of spinal deformity, hip flexion deformity, or lordosis and by age. Children with myelodysplasia who have strong quadriceps and stable neurological status can therefore have surgical stabilization of their hips with good results.

Evaluation of residual clubfoot deformities using gait analysis.

Gait analysis was used to evaluate 15 patients who had previously undergone clubfoot surgery. Because six patients had had bilateral surgery, 21 feet had undergone previous clubfoot surgery. Three of the operated feet had no residual deformity. In the remaining 18 feet, the reason for referral was intoeing in 13, calcaneovalgus in three, hindfoot varus in one, and supination/adduction in one. Clinical assessment and information from the gait analysis were used to establish a treatment plan. Satisfactory treatment outcome was achieved in 13 patients, one result was unsatisfactory, and one result was undetermined.

Clubfoot in the twentieth century: where we were and where we may be going in the twenty-first century.

In the twentieth century clubfoot was one of the commonest congenital deformities of the musculoskeletal system with an incidence in some races as low as 0.6 and in others as high as 6.8 per thousand live births (Polynesia). Males have the deformity twice as often as females. In the early 1900s forceful correction of the deformity as espoused by Hugh Owen Thomas was in vogue. In the 1930s Joseph Hiram Kite, like Hippocrates (400 BC), recommended repeated gentle manipulations to achieve a correction. Instead of bandages Kite used serial plaster casts to maintain the correction. During the late 1940s Ignatio Ponseti developed his technique of correction through the normal arc of the subtalar joint. In a clubfoot the soft tissues are more resistant to pressure than the bones. With this concept in mind soft tissue procedures were developed in which the capsules and ligaments were released surgically. With safer pediatric anesthesia the 1960s, 1970s, and 1980s saw surgical approaches that were more and more aggressive even including a complete subtalar release. The improved imaging modalities and computer graphics of the 1980s led to a better understanding of the pathoanatomy. Long-term follow-up studies demonstrating malcorrection, overcorrection, pain, and stiffness dampened the enthusiasm for very aggressive surgery. The main problem with surgery is that clubfoot wounds heal by a patching up process called repair. The losses are made good not with the original tissue but with a material that is biologically simple, cheap, and handy - connective tissue scar! As the century drew to a close there was a major swing of the pendulum to the Ponseti method. Surgeons are now learning the limitations of this method. Finally, the author tries to imagine what may happen in the future prevention, classification, and treatment of clubfoot with all the advances in cell biology, molecular biology, biomechanics, biomaterials, surgery, orthotics, and evidence-based medicine.

The role of arthroscopy in children.

The records for 156 consecutive arthroscopic examinations in children with knee complaints were reviewed. Diagnostic accuracy was based on subsequent arthrotomy and the clinical course in the absence of arthrotomy. All arthroscopies were performed by one person (NCC) between 1975 and 1979. Children under 12 years (most of them aged 6–11 years) accounted for 43 of the patients. The arthroscopic diagnoses were classified into three categories: very useful, useful, and not useful. Arthroscopy was found to be very useful in 30% of children in both age groups, those under and those over 12 years. In all these patients, unnecessary arthrotomies were avoided. Most (63%) of the arthroscopies were found to be useful, since they provided additional findings and biopsies. Only in 5% of cases did the arthroscopy fail to add any information. There were no complications from the procedure. Arthroscopy is an effective diagnostic tool that can be used safely in children.

Clubfoot analysis with three-dimensional foot models.

The purpose of this study was to develop a method of defining, in mathematical terms, the interpositional relationships of the bones of the hindfoot complex in the idiopathic clubfoot and the neurogenic clubfoot. The neurogenic clubfoot and contralateral normal-appearing foot of a stillborn infant with myelomeningocele, and the normal foot of a 10-year-old were sectioned with a cryomicrotome. Magnetic resonance images (MRIs) of the clubfoot and the normal foot of a 3-month-old boy were obtained. Using a computer program, three-dimensional foot models were generated from the digitized cryomicrotome sections and from the MRIs. The central principal axes were determined for the talus and calcaneus. The long central principal axes of the talus and calcaneus were neutrally rotated with reference to the bimalleolar axis in the idiopathic clubfoot while in the neurogenic clubfoot the long central principal axis of the talus was medially rotated 52 degrees and that of the calcaneus 10 degrees. The talocalcaneal angles defined by the long central principal axes in the superior and medial views were 0 degree and 10 degrees, respectively, in the idiopathic clubfoot, and 42 degrees and 56 degrees, respectively, in the neurogenic clubfoot.