Amy L. Ladd

Norian SRS cement compared with conventional fixation in distal radial fractures. A randomized study.

BACKGROUND A prospective, randomized multicenter study was conducted to evaluate closed reduction and immobilization with and without Norian SRS (Skeletal Repair System) cement in the management of distal radial fractures. Norian SRS is a calcium-phosphate bone cement that is injectable, hardens in situ, and cures by a crystallization reaction to form dahllite, a carbonated apatite equivalent to bone mineral. METHODS A total of 323 patients with a distal radial fracture were randomized to treatment with or without Norian SRS cement. Stratification factors included fracture type (intra-articular or extra-articular), hand dominance, bone density, and the surgeons preferred conventional treatment (cast or external fixator). The subjects receiving Norian SRS underwent a closed reduction followed by injection of the cement percutaneously or through a limited open approach. Wrist motion, beginning two weeks postoperatively, was encouraged. Control subjects, who had not received a Norian SRS injection, underwent closed reduction and application of a cast or external fixator for six to eight weeks. Supplemental Kirschner wires were used in specific instances in both groups. Patients were followed clinically and radiographically at one, two, four, and between six and eight weeks and at three, six, and twelve months. Patients rated pain and the function of the hand with use of a visual analog scale. Quality of life was assessed with use of the Short Form-36 (SF-36) health status questionnaire. Complications were recorded. RESULTS Significant clinical differences were seen at six to eight weeks postoperatively, with better grip strength, wrist range of motion, digital motion, use of the hand, and social and emotional function, and less swelling in the patients treated with Norian SRS than in the control group (p < 0.05). By three months, these differences had normalized except for digital motion, which remained significantly better in the group treated with Norian SRS (p = 0.015). At one year, no clinical differences were detected. Radiographically, the average change in ulnar variance was greater in the patients treated with Norian SRS (+2.0 mm) than in the control group (+1.4 mm) (p < 0.02). No differences were seen in the total number of complications, including loss of reduction. The infection rate, however, was significantly higher (p < 0.001) in the control group (16.7%) than in the group treated with Norian SRS (2.5%) and the infections were always related to external fixator pins or Kirschner wires. Four patients with intra-articular extravasation of cement were identified; no sequelae were observed at twenty-four months. Cement was seen in extraosseous locations in 112 (70%) of the SRS-treated patients; loss of reduction was highest in this subgroup (37%). The extraosseous material had disappeared in eighty-three of the 112 patients by twelve months. CONCLUSIONS Our results indicate that fixation of a distal radial fracture with Norian SRS cement may allow for accelerated rehabilitation. A limited open approach and supplemental fixation with Kirschner wires are recommended. Additional or alternate fixation is necessary for complex articular fractures.

Use of bone-graft substitutes in distal radius fractures.

The development of bone-graft substitutes potentially provides the benefits of bone grafting without the risks of autograft harvest. During the past few years, the US Food and Drug Administration has approved several different types of products. These vary considerably in composition, structural strength, osteoinductive and osteoconductive potential, and mechanisms and rates at which they are resorbed or remodeled. The products now approved for orthopaedic applications in the United States include those based on naturally occurring materials (e.g., demineralized human bone matrix, bovine collagen mineral composites, and processed coralline hydroxyapatite) as well as synthetic materials (e.g., calcium sulfate pellets, bioactive glass, and calcium phosphate cement). Materials in development include variations on available products and a new generation of biologically active materials employing growth factors. Rigorous comparison of the products is difficult, as there are no universally accepted preclinical assays and comparable clinical studies. Despite the limitations of the data now available, controlled studies and anecdotal reports suggest that use of bone-graft substitutes may result in improved treatment outcomes for patients with fractures of the distal radius.

Biomechanical evaluation of fixation of intra-articular fractures of the distal part of the radius in cadavera: Kirschner wires compared with calcium-phosphate bone cement.

BACKGROUND The purpose of this study was to compare the biomechanical efficacy of an injectable calcium-phosphate bone cement (Skeletal Repair System [SRS]) with that of Kirschner wires for the fixation of intraarticular fractures of the distal part of the radius. METHODS Colles fractures (AO pattern, C2.1) were produced in ten pairs of fresh-frozen human cadaveric radii. One radius from each pair was randomly chosen for stabilization with SRS bone cement. These ten radii were treated with open incision, impaction of loose cancellous bone with use of a Freer elevator, and placement of the SRS bone cement by injection. In the ten control specimens, the fracture was stabilized with use of two horizontal and two oblique Kirschner wires. The specimens were cyclically loaded to a peak load of 200 newtons for 2000 cycles to evaluate the amount of settling, or radial shortening, under conditions simulating postoperative loading with the limb in a cast. Each specimen then was loaded to failure to determine its ultimate strength. RESULTS The amount of radial shortening was highly variable among the specimens, but it was consistently higher in the Kirschner-wire constructs than in the bone fixed with SRS bone cement within each pair of radii. The range of shortening for all twenty specimens was 0.18 to 4.51 millimeters. The average amount of shortening in the SRS constructs was 50 percent of that in the Kirschner-wire constructs (0.51+/-0.34 compared with 1.01+/-1.23 millimeters; p = 0.015). With the numbers available, no significant difference in ultimate strength was detected between the two fixation groups. CONCLUSIONS This study showed that fixation of an intra-articular fracture of the distal part of a cadaveric radius with biocompatible calcium-phosphate bone cement produced results that were biomechanically comparable with those produced by fixation with Kirschner wires. However, the constructs that were fixed with calcium-phosphate bone cement demonstrated less shortening under simulated cyclic load-bearing.

Evaluation of a surgical simulator for learning clinical anatomy.

Background  New techniques in imaging and surgery have made 3‐dimensional anatomical knowledge an increasingly important goal of medical education. This study compared the efficacy of 2 supplemental, self‐study methods for learning shoulder joint anatomy to determine which method provides for greater transfer of learning to the clinical setting.

Three-dimensional kinematics of the upper limb during a Reach and Grasp Cycle for children

The ability to reach, grasp, transport, and release objects is essential for activities of daily living. The objective of this study was to develop a quantitative method to assess upper limb motor deficits in children with cerebral palsy (CP) using three-dimensional motion analysis. We report kinematic data from 25 typically developing (TD) children (11 males, 14 females; ages 5-18 years) and 2 children with spastic hemiplegic CP (2 females, ages 14 and 15 years) during the Reach and Grasp Cycle. The Cycle includes six sequential tasks: reach, grasp cylinder, transport to mouth (T(1)), transport back to table (T(2)), release cylinder, and return to initial position. It was designed to represent a functional activity that was challenging yet feasible for children with CP. For example, maximum elbow extension was 43+/-11 degrees flexion in the TD group. Consistent kinematic patterns emerged for the trunk and upper limb: coefficients of variation at point of task achievement for reach, T(1), and T(2) for trunk flexion-extension were (.11, .11, .11), trunk axial rotation (.06, .06, .06), shoulder elevation (.13, .11, .13), elbow flexion-extension (.25, .06, .23), forearm pronation-supination (.08, .10, .11), and wrist flexion-extension (.25, .21, .22). The children with CP demonstrated reduced elbow extension, increased wrist flexion and trunk motion, with an increased tendency to actively externally rotate the shoulder and supinate the forearm during T(1) compared to the TD children. The consistent normative data and clinically significant differences in joint motion between the CP and TD children suggest the Reach and Grasp Cycle is a repeatable protocol for objective clinical evaluation of functional upper limb motor performance.

Congenital cervical stenosis presenting as transient quadriplegia in athletes. Report of two cases.

The cases of two patients in whom complete but transient quadriplegia developed after an injury that was incurred while playing football are presented. Both patients were found to have a congenitally narrow cervical vertebral canal. Critical stenosis resulting in the transient quadriplegia occurred after a presumed injury to a cervical disc. In our opinion, a myelogram should be made for patients with a history of transient quadriplegia, numbness, or a burning sensation down the back or the lower extremities, even if other radiographic studies are interpreted as negative. Patients who have stenosis of the cervical spine should be advised to discontinue participation in contact sports.

Reconstructive osteotomy for malunion of the distal radius.

Common misconceptions about distal radius fractures result in undertreatment of many fractures, particularly in an active population. Loss of reduction of the fracture may cause a symptomatic malunion. Fourteen patients with an average age of 39 years (range, 21-65 years) underwent reconstructive procedures for radial malunions. The common malunion healed in a position of dorsal angulation, loss of radial inclination, and radial shortening. Ten patients had been treated by closed means, and 4 had undergone earlier surgical procedures without acceptable healing position of the fracture. Seven patients underwent a radial osteotomy alone, 5 patients had an osteotomy with an ulnar leveling procedure, and 2 patients had a Sauvé-Kapandji procedure alone. The average improvement in radial inclination was 14 ° (range, 0 °-34 °), volar tilt 21 ° (range, 2 °-33 °), and improvement in a positive ulnar variance by 6.8 mm (range, 0-48 mm). The complication rate was 29%, with a followup of 29 months (range, 12-43 months). Functional improvement was notable in 12 of 14 patients. Surgical reconstruction for malunions is technically difficult and may not completely restore the anatomy. Patient satisfaction, however, in terms of increased function, decreased pain, and decreased deformity is sufficiently high to warrant reconstructive treatment.

In Vivo Kinematics of the Thumb Carpometacarpal Joint During Three Isometric Functional Tasks

BackgroundThe thumb carpometacarpal (CMC) joint is often affected by osteoarthritis—a mechanically mediated disease. Pathomechanics of the CMC joint, however, are not thoroughly understood due to a paucity of in vivo data.Questions/purposesWe documented normal, in vivo CMC joint kinematics during isometric functional tasks. We hypothesized there would be motion of the CMC joint during these tasks and that this motion would differ with sex and age group. We also sought to determine whether the rotations at the CMC joint were coupled and whether the trapezium moved with respect to the third metacarpal.MethodsForty-six asymptomatic subjects were CT-scanned in a neutral position and during three functional tasks (key pinch, jar grasp, jar twist), in an unloaded and a loaded position. Kinematics of the first metacarpal, third metacarpal, and the trapezium were then computed.ResultsSignificant motion was identified in the CMC joint during all tasks. Sex did not have an effect on CMC joint kinematics. Motion patterns differed with age group, but these differences were not systematic across the tasks. Rotation at the CMC joint was generally coupled and posture of the trapezium relative to the third metacarpal changed significantly with thumb position.ConclusionsThe healthy CMC joint is relatively stable during key pinch, jar grasp, and jar twist tasks, despite sex and age group.Clinical RelevanceOur findings indicate that directionally coupled motion patterns in the CMC joint, which lead to a specific loading profile, are similar in men and women. These patterns, in addition to other, nonkinematic influences, especially in the female population, may contribute to the pathomechanics of the osteoarthritic joint.

Macroscopic and Microscopic Analysis of the Thumb Carpometacarpal Ligaments: A Cadaveric Study of Ligament Anatomy and Histology

BACKGROUND Stability and mobility represent the paradoxical demands of the human thumb carpometacarpal joint, yet the structural origin of each functional demand is poorly defined. As many as sixteen and as few as four ligaments have been described as primary stabilizers, but controversy exists as to which ligaments are most important. We hypothesized that a comparative macroscopic and microscopic analysis of the ligaments of the thumb carpometacarpal joint would further define their role in joint stability. METHODS Thirty cadaveric hands (ten fresh-frozen and twenty embalmed) from nineteen cadavers (eight female and eleven male; average age at the time of death, seventy-six years) were dissected, and the supporting ligaments of the thumb carpometacarpal joint were identified. Ligament width, length, and thickness were recorded for morphometric analysis and were compared with use of the Student t test. The dorsal and volar ligaments were excised from the fresh-frozen specimens and were stained with use of a triple-staining immunofluorescent technique and underwent semiquantitative analysis of sensory innervation; half of these specimens were additionally analyzed for histomorphometric data. Mixed-effects linear regression was used to estimate differences between ligaments. RESULTS Seven principal ligaments of the thumb carpometacarpal joint were identified: three dorsal deltoid-shaped ligaments (dorsal radial, dorsal central, posterior oblique), two volar ligaments (anterior oblique and ulnar collateral), and two ulnar ligaments (dorsal trapeziometacarpal and intermetacarpal). The dorsal ligaments were significantly thicker (p < 0.001) than the volar ligaments, with a significantly greater cellularity and greater sensory innervation compared with the anterior oblique ligament (p < 0.001). The anterior oblique ligament was consistently a thin structure with a histologic appearance of capsular tissue with low cellularity. CONCLUSIONS The dorsal deltoid ligament complex is uniformly stout and robust; this ligament complex is the thickest morphometrically, has the highest cellularity histologically, and shows the greatest degree of sensory nerve endings. The hypocellular anterior oblique ligament is thin, is variable in its location, and is more structurally consistent with a capsular structure than a proper ligament.

Temporal-spatial parameters of the upper limb during a Reach & Grasp Cycle for children

The objective of this study was to characterize normal temporal-spatial patterns during the Reach & Grasp Cycle and to identify upper limb motor deficits in children with cerebral palsy (CP). The Reach & Grasp Cycle encompasses six sequential tasks: reach, grasp cylinder, transport to self (T(1)), transport back to table (T(2)), release cylinder, and return to initial position. Three-dimensional motion data were recorded from 25 typically developing children (11 males, 14 females; ages 5-18 years) and 12 children with hemiplegic CP (2 males, 10 females; ages 5-17 years). Within-day and between-day coefficients of variation for the control group ranged from 0 to 0.19, indicating good repeatability of all parameters. The mean duration of the Cycle for children with CP was nearly twice as long as controls, 9.5±4.3s versus 5.1±1.2s (U=37.0, P=.002), partly due to prolonged grasp and release durations. Peak hand velocity occurred at approximately 40% of each phase and was greater during the transport (T(1), T(2)) than non-transport phases (reach, return) in controls (P<.001). Index of curvature was lower during transport versus non-transport phases for all children. Children with CP demonstrated an increased index of curvature during reach (U=46.0, P=.0074) and an increased total number of movement units (U=16.5, P<.0001) compared to controls, indicating less efficient and less smooth movements. Total duration of the Reach & Grasp Cycle (rho=.957, P<.0001), index of curvature during reach and T(1) (rho=.873, P=.0002 and rho=.778, P=.0028), and total number of movement units (rho=.907, P<.0001) correlated strongly with MACS score. The consistent normative data and the substantial differences between children with CP and controls reflect utility of the Reach & Grasp Cycle for quantitative evaluation of upper limb motor deficits.