How do different anterior tibial tendon transfer techniques influence forefoot and hindfoot motion?

BACKGROUND: Idiopathic clubfoot correction is commonly performed using the Ponseti method and is widely reported to provide reliable results. However, a relapsed deformity may occur and often is treated in children older than 2.5 years with repeat casting, followed by an anterior tibial tendon transfer. Several techniques have been described, including a whole tendon transfer using a two-incision technique or a three-incision technique, and a split transfer, but little is known regarding the biomechanical effects of these transfers on forefoot and hindfoot motion. QUESTIONS/PURPOSE: We used a cadaveric foot model to test the effects of three tibialis anterior tendon transfer techniques on forefoot positioning and production of hindfoot valgus. METHODS: Ten fresh-frozen cadaveric lower legs were used. We applied 150 N tension to the anterior tibial tendon, causing the ankle to dorsiflex. Three-dimensional motions of the first metatarsal, calcaneus, and talus relative to the tibia were measured in intact specimens, and then repeated after each of the three surgical techniques. RESULTS: Under maximum dorsiflexion, the intact specimens showed 6° (95% CI, 2.2°-9.4°) forefoot supination and less than 3° (95% CI, 0.4°-5.3°) hindfoot valgus motion. All three transfers provided increased forefoot pronation and hindfoot valgus motion compared with intact specimens: the three-incision whole transfer provided 38° (95% CI, 33°-43°; p < 0.01) forefoot pronation and 10° (95% CI, 8.5°-12°; p < 0.01) hindfoot valgus; the split transfer, 28° (95% CI, 24°-32°; p < 0.01) pronation, 9° (95% CI, 7.5°-11°; p < 0.01) valgus; and the two-incision transfer, 25° (95% CI, 20°-31°; p < 0.01) pronation, 6° (95% CI, 4.2°-7.8°; p < 0.01) valgus. CONCLUSION: All three techniques may be useful and deliver varying degrees of increased forefoot pronation, with the three-incision whole transfer providing the most forefoot pronation. Changes in hindfoot motion were small. CLINICAL RELEVANCE: Our study results show that the amount of forefoot pronation varied for different transfer methods. Supple dynamic forefoot supination may be treated with a whole transfer using a two-incision technique to avoid overcorrection, while a three-incision technique or a split transfer may be useful for more resistant feet. Confirmation of these findings awaits further clinical trials.

Inter- and intra-observer reliability of radiographic scores commonly used for the evaluation of haemophilic arthropathy.

Although the severity of haemophilic arthropathy is commonly assessed using established radiographic scoring systems, there is limited available information about their inter- and intra-observer reliability. The purpose of the present study was to establish the inter-observer reliability (IEOR) and intra-observer reliability (IAOR) of three different methods available for the classification of haemophilic arthropathy, including the Arnold and Hilgartner classification, a modification to the Arnold and Hilgartner system described by Luck et al., and the classification described by Pettersson et al. Antero-posterior and lateral radiographs of 54 haemophilic joints were included for the analysis. To determine the IEOR for each one of the three radiographic systems, the radiographs were randomly evaluated by four observers, including two orthopaedic surgeons, one orthopaedic resident and one haematologist. For the determination of IAOR, all four reviewers repeated the assessment in a similar fashion, after a period of at least 2 weeks. IEOR and IAOR for the three classification systems was established using kappa (kappa) statistics. A Spearman rank correlation was used to determine the similarities between each reviewer's own interpretative scales. The IEOR was low for the Arnold and Hilgartner system (kappa = 0.35, P < or = 0.001) and the Luck system (kappa = 0.38, P < or = 0.001), but even lower for the Pettersson system (kappa = 0.06, P = 0.1). For the Pettersson system, particularly low kappa values were observed for the presence or absence of osteoporosis (kappa = 0.11, P = 0.0027), enlarged epiphysis (kappa = 0.10, P = 0.0039), erosion of joint margins (kappa = 0.11, P = 0.0018), and joint deformity (kappa = 0.16, P = 0.00001). However, a relatively high Spearman rank correlation for all three scales [r(s) = 0.75 (P < 0.001) for Arnold and Hilgartner system, r(s) = 0.74 (P < 0.001) for the Luck system and r(s) = 0.81 (P < 0.001) for Pettersson system] indicated an overall, general agreement among the reviewers with regard to the severity of the haemophilic arthropathy. There was a moderate IAOR value for both, the Arnold and Hilgartner system (kappa = 0.57, P = 0.00001) and the Luck system (kappa = 0.62, P = 0.00001) with a low IAOR value for the Pettersson system [kappa = 0.22, P = 0.00001). Currently available radiographic scoring systems for haemophilic arthropathy have low inter- and intra-observer reliability rates. Improvements, either through education or modification of the scoring systems, are critical in an era where correlations between clinical and radiographic scores have received significant attention.

Simulation of extreme loads on the proximal femur for implant fixation assessment.

Total joint replacement patients today are younger, heavier, and more active than total joint replacement patients 40 yrs ago. Consequently, patient expectations and prosthesis requirements have increased and there is a need to re-evaluate preclinical testing methods. We present the design rationale for a novel load simulator for the proximal femur, capable of applying a more aggressive load profile than previous simulators. This simulator was used to measure three-dimensional micromotion of a cemented total hip replacement femoral stem under simulated physiological loading. We assessed the influence of a separate abductor muscle force, a higher joint reaction force, and a more accurate implant stability measurement system included in the new simulator and compared the results to the lower, single joint reaction force included in a previously published simulator. Per-cycle motion at both cement interfaces and stem and cement mantle migration obtained from both simulators using the same femoral stem design, are compared. Although the new simulator applied higher loads, per-cycle motions were lower than previously reported. In both studies, regardless of the presence or lack of a separate muscle force, the greatest motions were in the medial-lateral direction (new: 27 +/- 4 mum, old: 67 +/- 21 mum). The findings indicate that magnitude and direction of peak joint reaction force and inclusion of a separate muscle force have a significant effect on femoral stem stability measurements. We recommend that future femoral stem stability studies consider using load simulation techniques and a direct motion measurement system comparable to the one presented in this study.

Quantification of the ossification of the lateral cuneiform in the feet of young children with unilateral congenital talipes equinovarus.

AIMS: After the initial correction of congenital talipes equinovarus (CTEV) using the Ponseti method, a subsequent dynamic deformity is often managed by transfer of the tendon of tibialis anterior (TATT) to the lateral cuneiform. Many surgeons believe the lateral cuneiform should be ossified before surgery is undertaken. This study quantifies the ossification process of the lateral cuneiform in children with CTEV between one and three years of age. PATIENTS AND METHODS: The length, width and height of the lateral cuneiform were measured in 43 consecutive patients with unilateral CTEV who had been treated using the Ponseti method. Measurements were taken by two independent observers on standardised anteroposterior and lateral radiographs of both feet taken at one, two and three years of age. RESULTS: All dimensions of the lateral cuneiform on the affected side increased annually but remained smaller than the corresponding dimensions of the unaffected foot (p < 0.01). The lateral cuneiform resembled a 9 mm cube at two years and an 11 mm cube at three years. CONCLUSION: At one and two years, the ossification centre of the lateral cuneiform may not be large enough to accommodate a drill hole for tendon transfer. However, by three years, it has undergone sufficient ossification to do so. Cite this article: Bone Joint J 2017;99-B:1109-14.

Enhancement of fracture healing in the rat, modulated by compounds that stimulate inducible nitric oxide synthase: Acceleration of fracture healing via inducible nitric oxide synthase.

OBJECTIVES: We investigated the effects on fracture healing of two up-regulators of inducible nitric oxide synthase (iNOS) in a rat model of an open femoral osteotomy: tadalafil, a phosphodiesterase inhibitor, and the recently reported nutraceutical, COMB-4 (consisting of L-citrulline, Paullinia cupana, ginger and muira puama), given orally for either 14 or 42 days. MATERIALS AND METHODS: Unilateral femoral osteotomies were created in 58 male rats and fixed with an intramedullary compression nail. Rats were treated daily either with vehicle, tadalafil or COMB-4. Biomechanical testing of the healed fracture was performed on day 42. The volume, mineral content and bone density of the callus were measured by quantitative CT on days 14 and 42. Expression of iNOS was measured by immunohistochemistry. RESULTS: When compared with the control group, the COMB-4 group exhibited 46% higher maximum strength (t-test, p = 0.029) and 92% higher stiffness (t-test, p = 0.023), but no significant changes were observed in the tadalafil group. At days 14 and 42, there was no significant difference between the three groups with respect to callus volume, mineral content and bone density. Expression of iNOS at day 14 was significantly higher in the COMB-4 group which, as expected, had returned to baseline levels at day 42. CONCLUSION: This study demonstrates an enhancement in fracture healing by an oral natural product known to augment iNOS expression.Cite this article: R. A. Rajfer, A. Kilic, A. S. Neviaser, L. M. Schulte, S. M. Hlaing, J. Landeros, M. G. Ferrini, E. Ebramzadeh, S-H. Park. Enhancement of fracture healing in the rat, modulated by compounds that stimulate inducible nitric oxide synthase: Acceleration of fracture healing via inducible nitric oxide synthase. Bone Joint Res 2017:6:-97. DOI: 10.1302/2046-3758.62.BJR-2016-0164.R2.

Alteration in hypoplasia of the hindfoot structures during early growth in clubfeet treated using the Ponseti method.

PURPOSE: Previous reports have demonstrated diminished size of the hindfoot bones in patients with idiopathic clubfoot deformity. However, no study has quantified the percentage of hypoplasia as a function of early growth, during the brace phase of Ponseti treatment. METHODS: We measured the dimensions of ossified structures on radiographs in patients with unilateral Ponseti-treated clubfeet to determine changes in the percentage of hypoplasia between two and four years of age. RESULTS: The degree of hypoplasia varied among the osseous structures in Ponseti-treated clubfeet at age two years, with greater hypoplasia being observed in the talus (7.3%), followed by calcaneus (4.9%) and the cuboid (4.8%). Overall, the degree of hypoplasia diminished by four years, such that the degree of hypoplasia was greatest in the talus (4.2%) and the calcaneus (4.2%) followed by the cuboid (0.6%). At four years of age, the greatest degree of hypoplasia persisted in the talus and calcaneus. CONCLUSIONS: Changes occurred in the size of the ossification of hindfoot bones between two and four years of age, and the observed changes in the percentage of hypoplasia varied among the different structures. At four years of age, the greatest percentage of hypoplasia was observed in the talus and calcaneus at values similar to those previously reported in skeletally mature patients. The results suggested that the relative difference in size of the feet may be expected to remain constant in a child with a unilateral clubfoot after this age.

Stable partial debonding of the cement interfaces indicated by a finite element model of a total hip prosthesis.

A simplified three-dimensional finite element model of the femoral component of a cemented total hip prosthesis was used to investigate whether partial debonding at the stem-cement or bone-cement interfaces propagates in a stable or unstable manner, and to assess the resultant variation of the stresses within the cement layer. The likelihood of unstable debonding under tensile failure mode was assessed both by a conventional monotonic strength criterion and by a fracture mechanics approach that took into account debonding due to fatigue loading. The model predicted that partial debonding at the cement interfaces would be stable and would not precipitate complete debonding. Among the various bonding conditions that were investigated, the maximum tensile stress within the cement layer was least with a small amount of debonding rather than with complete bonding. These results were consistent with clinical observations of nonprogressive or slowly progressive separation at cement interfaces in cemented femoral components that were otherwise well functioning and asymptomatic.

Angular deformities and forearm function.

Angular deformities were created in cadaver forearms at proximal, middle, and distal third levels of the radius and ulna separately, and at middle and distal third levels of both bones, to determine the corresponding limitations of pronation and supination. The ranges of pronation and supination were recorded using a rotational motion measurement apparatus instrumented with a 360 degrees goniometer. These experimental results were compared to data obtained from clinical and radiographic examination of 105 patients with similar residual deformities following treatment of fractures by nonsurgical means, to evaluate the accuracy of the experimental model and to determine if loss of rotational motion could be predicted based on radiographic findings. With cadaver forearms, on the average, angulation of 10 degrees of the radius or ulna in coronal or sagittal planes limited pronation and supination by less than 24 degrees, whereas angulation of 10 degrees of both the radius and the ulna limited pronation and supination by less than 18%. Comparison of experimental results with clinical findings showed that, despite the errors involved in measuring forearm deformities in patients using biplanar radiographs, the experimental results predicted the clinical loss of pronation and supination to within 17% for the fractures of the radius, and within 8% accuracy for the fractures of the ulna.

Comparison of the stability of press-fit hip prosthesis femoral stems using a synthetic model femur.

The motion of three different press-fit hip prosthesis femoral components was compared with that of a cemented stem and an Austin Moore noncemented hemiarthroplasty. Synthetic composite femurs were used as an experimental model to reduce the variations in shape and quality typical among cadaver femurs. Motion was measured under axial and rotational loading approximating a walking load. On the initial application of load, axial subsidence was as much as several millimeters for the noncemented stems. Considerable tightening occurred during the 5,000 walking cycles, such that the motion of the noncemented stems in some directions eventually was as small as that of the cemented stem, on the order of tens of microns.

Control of motion of tibial fractures with use of a functional brace or an external fixator. A study of cadavera with use of a magnetic motion sensor.

A computer-linked magnetic motion transducer was used to monitor and record the six components of motion of the bone fragments in eight cadaveric tibiae in which a simulated, oblique fracture of the middle of the shaft had been stabilized with a functional brace. The limbs were mounted in a servo-hydraulic testing frame, and a cyclic load of 150 newtons was applied along the axis of the tibia. Motion sensors, attached to each side of the fracture, measured and displayed the values of the three translations (axial, anterior-posterior, and medial-lateral), the axial rotation, and the two angulations (anterior-posterior and varus-valgus) as they occurred. Although only an axial load was applied, the off-axis motions were comparable in magnitude with the motion along the axis. The elastic (recoverable) translations of the fragments ranged from 0.5 to 1.9 millimeters, about four to ten times larger than the corresponding motions that were recorded in an earlier study of such fractures that had been stabilized with two types of external fixators. The recoverable rotation and angulations of the fragments of the limbs in the functional brace ranged from 0.7 to 1.2 degrees, about ten times those recorded when the external fixators were used.

Use of the Taguchi method for biomechanical comparison of flexor-tendon-repair techniques to allow immediate active flexion. A new method of analysis and optimization of technique to improve the quality of the repair.

The current trend toward early active flexion after repair of the flexor tendons necessitates a stronger repair than that provided by a modified Kessler technique with use of 4-0 nylon suture. The purpose of the current study was to determine, with use of the Taguchi method of analysis, the strongest and most consistent repair of the flexor tendons. Flexor tendons were obtained from fresh-frozen hands of human cadavera. Eight flexor tendons initially were repaired with the modified Kessler technique with use of 4-0 nylon core suture and 6-0 nylon epitenon suture. A test matrix was used to analyze a total of twenty variables in sixty-four tests. These variables included eight techniques for core-suture repair, four types of core suture, two sizes of core suture, four techniques for suture of the epitenon, and two distances from the repair site for placement of the core suture. After each repair, the specimens were mounted in a servohydraulic mechanical testing machine for tension-testing to failure. The optimum combination of variables was determined, with the Taguchi method, to be an augmented Becker technique with use of 3-0 Mersilene core suture, placed 0.75 centimeter from the cut edge with volar epitenon suture. The four-strand, double modified Kessler technique provided the second strongest repair. Five tendons that had been repaired with use of the optimum combination then were tested and compared with tendons that had been repaired with the standard modified Kessler technique. With the optimum combination of variables, the strength of the repair improved from a mean (and standard deviation) of 17.2 +/- 2.9 to 128 +/- 5.6 newtons, and the stiffness improved from a mean of 4.6 to 16.2 newtons per millimeter.

The cement mantle in total hip arthroplasty. Analysis of long-term radiographic results.

The correlation between the thickness of the cement mantle, the medullary canal fill, and the orientation of the stem and the long-term radiographic outcome of 836 cemented femoral components in patients who had a primary total hip replacement was assessed with use of survival analysis over a twenty-one-year follow-up period. The femoral stems of hips that had a two to five-millimeter-thick cement mantle in the proximal medial region had a better outcome than stems implanted with a thicker or thinner cement mantle. Stems in femora with less than two millimeters of proximal medial cancellous bone had a better outcome than stems in femora with thicker cancellous bone. Stems that filled more than half of the medullary canal had better radiographic results than those that filled half or less. Progressive loosening, fracture of the cement, and radiolucent lines at the stem-cement or bone-cement interfaces were more likely to develop in stems that were oriented in more than 5 degrees of varus than in those in neutral or valgus. The noted correlations were true whether the stem was made of titanium alloy or of stainless steel. The results of this study emphasize the importance of careful preoperative planning in total hip arthroplasty done with cement and provide guidelines for the selection of the shape, size, and position of the stem.

The effect of fibular malreduction on contact pressures in an ankle fracture malunion model.

Nine fresh-frozen cadaveric specimens were disarticulated through the knee, and the soft tissues, except for the interosseous ligaments and interosseous membrane, were removed to the level of the ankle. The subtalar joint was secured with screws in neutral position (approximately 5 degrees of valgus). Contact pressures in the tibiotalar joint were measured with use of low-grade pressure-sensitive film, which was placed through an anterior capsulotomy. For each measurement, 700 newtons of load was applied to the specimen for one minute. The film imprints were scanned, and the contact pressures were quantitated in nine equal quadrants over the talar dome. A fracture-displacement device was secured to the distal end of the fibula; the device allowed for individual or combined displacements consisting of shortening, lateral shift, and external rotation of the fibula. The ankle was maintained in neutral flexion. The ligamentous injury associated with a pronation-lateral rotation fracture of the ankle was simulated by dividing the deep fibers of the deltoid ligament, the anterior-inferior tibiofibular ligament, and the interosseous membrane to a point that was an average of fifty-three millimeters proximal to the ankle joint. Baseline contact area and contact pressure in the joint were determined, followed by measurements after two, four, and six millimeters of shortening of the fibula; after two, four, and six millimeters of lateral shift of the fibula; and after 5, 10, and 15 degrees of external rotation of the fibula. The three types of displacement were tested individually as well as in combination. The simulated deformities were found to cause a shift of the contact pressure to the mid-lateral and posterolateral quadrants of the talar dome, with pressures as high as 4.1 megapascals. A corresponding decrease in the contact pressures was noted in the medial quadrants of the talar dome. The highest pressures were recorded for maximum shortening of the fibula, the combination of maximum shortening and lateral shift, the combination of maximum shortening and external rotation, and the combination of maximum shortening, lateral shift, and external rotation. In general, increases in each displacement variable corresponded to increasing contact pressures.

In vivo wear of titanium-alloy hip prostheses.

We examined samples of tissue and components that had been removed during twenty revisions of total hip arthroplasties in which a titanium-alloy femoral component had been used. Minute amounts of metallic debris were detected in the tissues from two patients. The amounts of polyethylene and methylmethacrylate debris and the histological reactions in the tissues corresponded closely with those reported in earlier studies of total hip prostheses made of stainless steel or cobalt-chromium alloy.

Total hip arthroplasty with cement. A long-term radiographic analysis in patients who are older than fifty and younger than fifty years.

The long-term performance of a total of 712 Charnley and STH prostheses was evaluated as a function of the patient's age (older than fifty years or younger than fifty years) and of the underlying disease (osteoarthrosis, rheumatoid arthritis, or avascular necrosis). In patients who were older than fifty years, there were lower incidences of continuous cement-bone radiolucency about the acetabular component (p = 0.04), wear of the polyethylene acetabular cup (p = 0.03), and resorption of the calcar (p = 0.03). However, larger percentages of younger patients had rheumatoid arthritis or avascular necrosis. In the cohort of patients who had osteoarthrosis, the performance of the prosthesis did not differ significantly between older and younger patients; therefore we attributed the differences that were observed to the disease--that is, to rheumatoid arthritis or avascular necrosis.

Cup containment and orientation in cemented total hip arthroplasties.

We reviewed the radiographs of 864 Charnley and STH (Zimmer) cemented total hip arthroplasties with a mean follow-up of seven years (maximum 16 years). Survivorship analysis was used to assess the correlation between radiographic performance and the bony containment or the coronal orientation of the acetabular cup. The cup orientation and containment were interrelated; all vertically oriented cups were completely contained, whereas 25% of more horizontal cups were only partially contained. Completely contained cups had significantly lower incidences of complete cement-bone radiolucency (p = 0.02) and of wear (p = 0.09). Vertically oriented cups had a lower incidence of continuous radiolucency than neutrally oriented cups, but this was not statistically significant (p = 0.25). Our results confirm the importance of complete bony containment, and also indicate that it is better to accept vertical orientation and obtain full bony coverage than to have a more horizontal orientation with partial containment.

Total hip replacement after failed hemiarthroplasty or mould arthroplasty. Comparison of results with those of primary replacements.

We compared the radiographic results of secondary total hip replacements, 99 following failed uncemented hemiarthroplasties and 21 following failed mould arthroplasties, with those of 825 primary cemented total hip replacements. The probability of occurrence of a number of radiological changes over time was calculated using survival analysis. The mean follow-up was 7.6 years (range one month to 20 years). The performance of the secondary total hip replacements varied with the preceding implant and was different for acetabular and femoral components. The incidence of radiological loosening was higher for femoral components implanted after failed hemiarthroplasties and for acetabular components after failed mould arthroplasties. However, the incidence of continuous radiolucent lines was lower for the acetabular components of converted hemiarthroplasties than for the primary replacements.

Characteristics of degeneration in an unstable knee with a coronal surface step-off.

To investigate the effect of instability on the remodelling of a minor articular surface offset, we created a 0.5 mm coronal step-off of the medial femoral condyle in 12 New Zealand white rabbits and transected the anterior cruciate ligament (ACL). A control group of 12 rabbits had only ACL resection and the opposite knee was used as the non-operated control. The osteoarthritic changes at 6, 12 and 24 weeks after surgery were evaluated histologically. In addition, changes in the immunological detection of 3-B-3(-) and 7-D-4 chondroitin-6-sulphate epitopes were determined because of the previous association of such changes with repair of cartilage and early osteoarthritis. In the instability/step-off group there was rapidly progressing focal degeneration of cartilage on the high side of the defect, not seen in previous step-off studies in stable knees. The rest of the femoral condyles and the tibial plateaux of the instability/step-off group had moderate osteoarthritis similar to that of the instability group. 3-B-3(-) was detectable in the early and the intermediate stages of osteoarthritis but no staining was seen in the severely damaged cartilage zones. Immunoreactivity with 7-D-4 increased as degeneration progressed.

Open fractures of the forearm in children.

OBJECTIVE: To describe the epidemiology, early results of treatment, and complications associated with open fractures of the forearm in children. DESIGN: Retrospective review of patients treated according to protocol. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: All children with an open fracture of the forearm during a four-year period (n = 76). Fourteen patients were excluded because of inadequate follow-up or incomplete medical records. INTERVENTION: All fractures were treated with irrigation and debridement, and parenteral antibiotics. Twenty-five patients were managed with cast immobilization only, and the remaining thirty-seven, with internal fixation either with transcutaneous pins, intramedullary pins, or plates and screws, followed by immobilization in a cast. MAIN OUTCOME MEASUREMENTS: Time to union, angular alignment at union, and incidence of complications. RESULTS: The average time to union was 8.9 weeks (median, eight weeks; range, 6 to 17 weeks). There were no nonunions, but three of the sixty-two fractures had delayed union. Eight of the sixty-two fractures healed with an angular deformity of more than 10 degrees, and two developed infections, one deep and one superficial. There were three preoperative and four postoperative nerve palsies, which all resolved spontaneously. CONCLUSIONS: Open fractures of the forearm in children, treated with prompt administration of parenteral antibiotics followed by debridement, were associated with a fairly low incidence of complications. Although we found that the use of some form of internal fixation tended to reduce both the need to remanipulate these fractures (p = 0.08), and to minimize the incidence of angular deformity greater than 10 degrees (p = 0.16), these findings did not reach statistical significance.

A review of ankle arthrodesis: predisposing factors to nonunion.

The purpose of this study was to review 15 years of experience with ankle fusions, specifically addressing the underlying etiology of ankle pathology, incidence of nonunion, and associated predisposing conditions that can lead to nonunion. Seventy-eight ankle fusions, performed between 1975 and 1990, were reviewed for this study. The average follow-up was 4 years. Patients with nonunion were evaluated separately to look at the predisposing factors that may have lead to nonunion. Factors associated with nonunion included fracture type, evidence of avascular necrosis, infection, major medical problems, and open injuries. Factors that were not associated with nonunion included age, past history of subtalar or triple arthrodesis, and technique.