Low-profile Implants Research Articles

Dysphagia After Anterior Cervical Spine Surgery: Pathophysiology, Diagnosis, and Management.

Anterior cervical spine surgery (ACSS) is a surgical intervention widely used for a myriad of indications including degenerative, oncologic, inflammatory, traumatic, and congenital spinal conditions. A primary concern for surgeons performing ACSS is the postoperative development of oropharyngeal dysphagia. Current literature reports a wide incidence of this complication ranging from 1 to 79%. Dysphagia after ACSS is multifactorial, with common risk factors being prolonged duration of operation, revision surgeries, multilevel surgeries, and use of recombinant human bone morphogenetic protein-2. Many technical strategies have been developed to reduce the risk of postoperative dysphagia, including the development of low-profile implants and retropharyngeal local steroid application. In this article, we review the most recent literature regarding the epidemiology and pathophysiology, diagnostic criteria, risk factors, and management of dysphagia after ACSS.

Modified Lemaire Lateral Extra-Articular Tenodesis Using an Inlay Technique and All-Suture Knotless Anchor Fixation

Appreciation of persistent anterolateral rotatory instability and graft failure after anterior cruciate ligament (ACL) reconstruction procedures has led surgeons to adopt the addition of lateral extra-articular tenodesis (LET) in both the revision and primary setting. Multiple techniques have been shown to eliminate anterolateral rotatory instability and reduce forces on the ACL graft, which has translated to lower re-rupture rates and improved patient outcomes. The risk of ACL/LET tunnel convergence can potentially compromise the fixation of one or both graft reconstructions. This article describes a technique for LET fixation which minimizes the depth of the LET femoral bone socket and utilizes low-profile implants thus mitigating this risk.

Risk Factors for Early Mechanical Failure and Revision in Modern Total Ankle Replacements

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle replacements (TAR) have rapidly advanced in terms of volume, technique, design, and indications. However, they are still at risk for failure and need for revision, even early in the postoperative period. Although recently there has been extensive research on TAR, many studies are limited in their power and sample size to assess risk factors for failure/revision. Using a large multi-surgeon retrospective database, we sought to describe the incidence and etiology of mechanical failure across modern implants. We also aimed to identify risk factors for early mechanical failure. We hypothesized that greater body mass index (BMI) and ipsilateral hindfoot fusion would be predictors of mechanical failure, and that implants with greater extent of tibial fixation (stems and keels) would be protective against mechanical failure. Methods: This is a single-center retrospective review of TAR patients in a prospective database. Adults undergoing primary TAR using any implant (Cadence, Inbone, Infinity, Invision, Salto, STAR, Vantage, Zimmer) who were minimum 2 years post-surgery were included. Exclusion criteria included revision TAR or patients undergoing ankle fusion takedown and conversion to TAR. Five surgeons contributed patients. Demographics, etiology of arthritis, operative data, and postoperative complications, reoperations, and revisions were collected. Revisions and reoperations were classified by standard criteria. Cause of revision was recorded. There were 560 TARs eligible for 2-year follow-up (mean 3.9 +- 1.1 years postoperative), with mean follow-up of 2.2 +- 1.4 years (range 1-71 months). The cohort had mean age 63.8 +- 9.1 years, BMI 29.4 +- 5.2 kg/m2, and 57% were male. Kaplan- Meier survival plots were created. Risk factors for revision due to mechanical failure were analyzed using multivariable logistic regression with partial Wald chi square statistics. Results: Most implants were low-profile (n=444, 79.3%), with 28 implants having tibial keels (5%) and 88 with tibial/talar stems (15.7%). There were 25 (4.5%) revisions of tibial and/or talar components at mean 1.6 years after index surgery (Figure). Preoperative coronal deformity did not impact revision rates (p=0.433). Patients who underwent revision for mechanical failure had significantly higher rates of concomitant hindfoot fusion (20% vs. 8.4%, p=0.047) and greater BMI (31.4 kg/m2 vs. 29.3 kg/m2, p=0.04). In multivariable logistic regression, hindfoot fusion was just short of statistical significance (odds ratio [OR] 2.96, p=0.056), and BMI was not significant (OR 1.05, p=0.417). Stemmed or keeled implants did not significantly decrease revision rates compared to low-profile implants, although the revision rate of stemmed implants was substantially low (1/88, 1.1%). Conclusion: Among 560 modern TAR implants, short-term survivorship was 95% at 2-year follow-up, which is consistent with existing studies. Patients who underwent revision for early mechanical failure had significantly higher BMI and rates of hindfoot arthrodesis. However, these variables fell short of statistical significance in multivariable regression, suggesting that there are either additional factors contributing to revision, or a larger cohort is needed. In addition, these results are likely biased by surgeons' tendencies to use stemmed implants in patients with hindfoot fusions. Further research is warranted to determine if stemmed implants provide a protective effect in these high-risk patients.

Combined limited internal fixation and multiplanar external fixation for immediate weight bearing of fractures around the foot and ankle.

Treatment of fractures around the foot and ankle can be challenging in patients who are unable to remain non weight bearing on their lower extremity. Traditional implants are not sufficient to resist loads incurred during weight bearing and can also lead to complications related to wound healing and infection. We describe a technique for fracture fixation of the foot and ankle that uses low profile implants to minimize soft tissue insult combined with multiplanar external fixation to allow for immediate weight bearing.

Treatment of Metacarpal and Phalangeal Fractures

Metacarpal and phalangeal fractures are the second most frequent fractures of the upper extremity. Treatment goal is to restore the function of the injured hand. Due to better understanding of anatomy and biomechanics as well as the development of locking and low-profile implants for osteosynthesis of such fractures, there is a growing safety when choosing the operative treatment for the correct indication. Nevertheless, conservative treatment of these injuries still plays an important role.

Les plaques préchantournées de la clavicule disponibles sur le marché s’appliquent-elles de façon optimale ? Étude cadavérique et revue de la littérature

PurposeThe indication for operative treatment of displaced midshaft clavicle fractures remains controversial. However, if plate fixation is considered, implant prominence and skin irritation are the most common causes for re-operation. Low profile implants as well as closely contouring plates to the individual anatomy may reduce these complications. The aim of this study was to compare the fitting accuracy and implant prominence of 3.5mm pelvic reconstruction plates (PRP) with pre-contoured anatomical clavicle plates (PACP) for midshaft clavicle fractures. MethodsThree-dimensional data of the largest, median and smallest male and female clavicle of an existing database of 89 cadaveric clavicles were included for analysis. A three-dimensional model of a commercially available PACP was used for digitally positioning of the plate on the segmented clavicles. Three-dimensional printouts of each clavicle were produced and the 3.5mm reconstruction plates were manually bent and positioned by the senior author. Computed tomography scans and three-dimensional reconstructions were then obtained to digitally compare the fitting accuracy and implant prominence. ResultsPelvic reconstruction plates offered superior fitting accuracy and lower implant prominence compared to PACP. The largest difference in implant prominence was observed in large sized female clavicles and measured 3.6mm. ConclusionBoth, the less costly PRP plates and commercially available PACP for midshaft fractures of the clavicle demonstrated a clinically acceptable fitting accuracy. The manually bent pelvic-reconstruction plates demonstrated reduced implant prominence with superior fitting. Hypothetically, this might contribute to a reduced rate of reoperation. Level of evidenceLevel IV cadaveric study.

Do low profile implants provide reliable stability in fixing the sternal fractures as a "fourth vertebral column" in sternovertebral injuries?

Flexion and compression forces to the trunk can cause severe instability of the vertebral column and the anterior chest wall, mostly associated with an unstable fracture of the sternum. In combination, the worst case would be a complete disruption of the trunk. Some authors consider the sternum-rib-complex to be the fourth vertebral column. This study discusses the possibilities to treat instable trunk injuries with sternal fractures concomitant to vertebral spine fractures through anterior sternal plating employing a locked plate osteosynthesis in a low profile design instead of the use of bulky implants. 11 Patients suffering from at least one fracture of a vertebral body in combination with an unstable sternum fracture were stabilized through a locked plate osteosynthesis in low profile design at the sternum between November 2011 and October 2014. The vertebral spine injury was stabilized as well, if necessary. Patients were followed up with a look at the consolidation of the fractures and the question if any failure of the implants occurred. Anterior sternal plating was uneventful in all cases. All Sternal fractures showed sufficient consolidation. No failure of implants has been seen during follow up over two years.. A locked plate osteosynthesis of a sternal fracture in low profile design seem to be an appropriate option for stabilization of the sternum in combined sternovertebral injuries.

Fixation Options for the Volar Lunate Facet Fracture: Thinking Outside the Box.

Background Fractures of the distal radius with small volar ulnar marginal fracture fragments are difficult to stabilize with standard volar locking plates. The purpose of this study is to describe alternative techniques available to stabilize these injuries. Materials and Methods Five patients were identified retrospectively with unstable volar lunate facet fracture fragments treated with supplemental fixation techniques. The demographic data, pre- and postoperative radiographic parameters, and early outcomes data were analyzed. The AO classification, preoperative and final postoperative ulnar variance, articular step-off, volar tilt, radial inclination, and teardrop angle were measured. The lunate subsidence and length of the volar cortex available for fixation were measured from the initial injury films. Description of Technique Lunate facet fixation was based on the morphology of the fragment, and stabilization was achieved with headless compression screws in three patients, a tension band wire construct in one, and two cortical screws in another. Results Five patients with a mean age of 58 years (range: 41-82) were included. There were two AO C3.2 and three B3.3 fractures. Preoperative radiographic measurements including radial inclination, tilt, and ulnar variance all improved after surgery and were maintained within normal limits at 3-month follow-up. There was no change in the teardrop angle at final follow-up (70-64 degrees; p = 0.14). None of the patients had loss of fixation or volar carpal subluxation. The mean visual analog scale pain score at 3 months was 1 (range: 0-2). Conclusions The morphology of volar lunate facet fracture fragments is variable, and fixation must be customized to the particular pattern. Small fragments may preclude the use of plates and screws for fixation. These fractures can be managed successfully with tension band wire constructs and headless screws. These low-profile implants may decrease the risk of tendon irritation that might accompany distally placed plates.

Folded breast implant’s pointed edge causing thinning of the skin

Sir, Aesthetic breast augmentation can be fraught with postoperative complications, particularly capsular contracture, malrotation, skin surface irregularities, and implant or inframammary fold malposition. However, we found only one report from 1972, 6 years after introduction of silicone breast implants, which describes Bthe folded breast sign^ as a radiological appearance rather than a clinical sign of a pointed Silastic shell [1]. Since we have corrected this late complication with conspicuous skin thinning several times in the past, we present today on two patients, both slim and tall and without any detectable thorax asymmetry. Two smooth-walled, soft, round, and lowprofile implants had been inserted into the sub-mammary space through the trans-axillary approach [2] in both patients 6 and 5 years prior. Both patients showed absolutely soft breast and had never developed a Baker II–IV capsule. One patient, a 24-year old student received 240 cm smoothwalled implants 5 years ago and recognized the pointed edge in the upper outer quadrant of the right breast (Fig. 1a) about 1 year after augmentation. The implant appeared vertically folded, and its protruding tip could be hidden behind the vertical bra strip. When the tip slowly thinned out the covering dermis, the patient asked for treatment. The implant pocket was so wide that a turning maneuver of the implant counter-clockwise from outside was successful. No pointed tip was palpable, and the implant appeared to be unfolded for over 9 months by now (Fig. 1b). The thinned out skin area recovered by itself after the pressure and rubbing from the inside subsided. The other patient, a 36 year-old riding instructor received two smooth-walled implants of 320 cm 6 years ago and developed a palpable and visible pointed implant tip also approximately 1 year later in the inner lower quadrant of her left breast. Under the impression of a capsule contracture as the cause for folding, she had been re-operated in the meantime three times by widening the pocket but leaving the implant. Early reoccurrence of the implant folding created the same pointed tip each time. Within a few weeks, the subcutaneous fat disappeared under pressure and slight rubbing and the implant edge shined through the skin in an area of about 2 cm in diameter (Fig. 2a). Both smooth implants could be moved easily upwards within their normal wide pockets, but the horizontally folded implant could not be kept unfolded by external maneuvers. Breast sonography [3] showed a clear fold with a pointed tip of the shell in front of the lower edge of the sternum. Checking all available implants on aesthetic surgery meetings, folding was possible in all presently available textured or smooth cohesive implants from all manufacturers (Fig. 3a, b). The only implant which could not be folded was Allergan’s cohesive textured high-profile implant Natrelle (Allergan, Irvine, California, USA) CHP-345 with 12 cm in diameter. Consequently, we inserted this implant in both breasts through a new inframammary incision. The thinned out skin area on the left breast was supported with a triangle-shaped capsular-fascial flap of 6 cm in length, raised from the pectoral muscle [4, 5]. An alternative solution would have been subpectoral implantation, which will support the recovery of thinned out skin in the upper but not in lower quadrants. Twelve months after corrective surgery, both breasts looked perfect without any signs of unevenness or skin thinning (Fig. 2b). Both breasts were firmer than before revision but did not bother the happy patient. * Gottfried Lemperle lemperle8@aol.com

Radiographic Lucency around Pedicle Screws with Cobalt Chromium Rod Constructs in the Setting of Lumbar Fusion

Background Context: Hybrid spinal implants that combine cobalt-chrome rods with titanium screws have been introduced with the goal of reducing the profile of implants used for lumbar fusion. 4.5mm and 4.75mm cobalt-chrome rods have been reported by the manufacturers as having similar results in biomechanical testing to conventional 5.5mm titanium rods, however little is known about the long-term clinical performance of these implants. This report discusses an interesting radiographic finding routinely encountered in our practice following use of these implants. Purpose: To describe the occurrence of radiographic lucency surrounding pedicle screws following the use of low-profile hybrid spinal implants for instrumented posterior lumbar fusion. Study Design: Case report. Methods: This is an observational case series of 14 patients undergoing lumbar fusion instrumented with hybrid cobalt/chrome – titanium implants. All cases involved instrumented posterior lumbar fusion for the treatment of degenerative spondylolisthesis. Patients were followed for one year with radiographic evaluation of both screw lucency and bony fusion as well as subjective outcomes including visual analog scale (VAS) pain score and Oswestry disability index (ODI). Results: At one year post-operative, all 14 patients had radiographic lucency around at least two pedicle screws in the construct despite radiographic bony fusion. All patients reported subjective improvement in VAS score and ODI, and all patients returned to work within 3 months post-operative. Conclusion: We note a 100% rate of pedicle screw lucency in our series of patients undergoing posterior spinal fusion instrumented with hybrid lowprofile cobalt-chrome implants. Lucency around pedicle screws has been previously associated in the literature with screw loosening, micro motion, and pseudo arthrosis. Despite this observation, the patients in our series subjectively report favorable outcomes. The significance and cause of lucency around pedicle screws with these low-profile implants is unknown, but may be due to decreased construct stiffness related to smaller rod diameter. Long-term experience with these implants is lacking and further studies are warranted.

Periprosthetic breast capsules and immunophenotypes of inflammatory cells

BackgroundSilicone gel-containing breast implants have been widely used for aesthetic and reconstructive mammoplasty. The development of a periprosthetic capsule is considered a local reparative process against the breast implant in which a variety of inflammatory cells may appear. Nevertheless, only few reports have evaluated the immunophenotypes of those inflammatory cells. Herein, we aim to provide more information in this regard evaluating 40 patients with breast implants.MethodsWe studied the immunophenotype of the inflammatory cells of capsular implants using antibodies against lymphocytes (CD3, CD4, CD8, CD20, CD45, and CD30) and histiocytes (CD68). Percentages of CD3 and CD20 positive cells were compared using the unpaired Student's t test. Fisher's test was also used to compare Baker grades by implant type, implant profile, and location and the presence of inflammatory cells by implant type.ResultsThe associations between Baker grades and implant type and location were statistically nonsignificant (p = 0.42 in both cases). However, the use of low profile implants was significantly associated (p = 0.002) with a higher proportion of Baker grades 3 and 4. We found evidence of inflammation in 92.5 % of all implant capsules, with a statistically significant (p = 0.036) higher proportion in textured breast implants. T cells predominated over B cells. Textured implants elicited a more marked response to T cells than smooth implants, with a similar proportion of helper and cytotoxic T cells. Textured implants showed statistically significant higher percentages of CD3 positive cells than smooth implants. Percentages of CD20 positive cells were similar in textured and smooth implants.ConclusionsThese results suggest that textured breast implants might induce a stronger local T cell immune response. Our findings could shed some light to understand the association of silicone breast implants and some cases of anaplastic large cell lymphomas.Level of Evidence: Level III, prognostic study.

Anterior short correction in thoracic adolescent idiopathic scoliosis with mini-open thoracotomy approach: prospective clinical, radiological and pulmonary function results

This is a prospective study of adolescent patients in whom idiopathic thoracic scoliosis was corrected by short anterior fusion through a mini-open thoracotomy approach. Clinical, radiological and pulmonary function results of minimal 2-year (2-6) follow-up are presented. Consecutive 62 patients with Lenke 1 and 2 curves, having main thoracic scoliosis of up to 75°, were prospectively included. The shoulder imbalance in Lenke 2 patients was less than 20 mm. Thoracic scoliosis was corrected by short anterior fusion. The thoracic spine was exposed by an 8-cm mini-open thoracotomy incision. The operation technique and choosing of fusion levels are thoroughly described. Complete 360° discectomies and convex side vertebral endplates osteotomies are essential for deformity corrections with short fusions. Single-rod 5.5-mm titanium implants were used. The age at the time of operation was mean 15.2 years; 56 patients had a single thoracic curve and 6 patients had a double thoracic curve. There were almost equal numbers of patients with lumbar modifier A, B or C. The average length of fusion was 5.5 (4-7) vertebrae. The average length of fusion was 3.5 (2-6) vertebrae shorter than the average curve length. The instrumented thoracic curves improved by 58.3% at 6 weeks and 56.3% at the last follow-up. Apex thoracic vertebral rotation improved by 73.78% at 6 weeks and 76.24% at the last follow-up. The non-instrumented upper thoracic curve improved by 25% in double thoracic scoliosis, where the mid-thoracic curve was selectively fused, and the non-instrumented lumbar curves improved by 33.9% at the last follow-up. The radiological changes from 6 weeks to the last follow-up were statistically not significant. The clinical rib hump improved by 54% at the last follow-up. There were no significant changes in the pulmonary function. FVC% was 81.04% preoperatively, 76.41% at 6 months and 80.38% at the 2-year follow-up. The results of SRS 24 questionnaire improved from a total of 61.40 points preoperatively to 100.50 points at 6 months and 98.62 points at the 2-year follow-up. There were no neurological or thoracotomy related complications, no pseudarthrosis, no implant pullout or breakage. A good deformity correction without loss of correction or adding on, a good cosmetic result and good patient's satisfaction were achieved through shorter than end-to-end thoracic fusions. The radiological residual deformity is acceptable. Anterior correction of thoracic scoliosis with a short spinal fusion is recommended to keep the large part of the spine mobile. A very short fusion, small thoracotomy incision, low-profile implants and complete closure of parietal pleura are keys to prevent reduction in postoperative lung function.

Surface Replacement Arthroplasty of the Proximal Interphalangeal Joint

The first proximal interphalangeal joint (PIPJ) replacements were hinged devices with single-axis motion. Newer implant arthroplasties of the PIPJ have anatomically designed proximal phalangeal and middle phalangeal components. A need to create balanced forces across the joint was the rationale for the semiconstrained PIPJ prosthesis, which uses an anatomic design. These low-profile implants limit bone excision while preserving the integrity of the collateral ligaments. Paramount in the success of this implant is maintaining the integrity of the insertion of the central slip as it inserts on the base of the middle phalanx. The proximal and middle phalanx should be broached such that the largest implant can be press-fit in place. Greater stability is gained with a collateral ligament-preserving implant. Patient selection should include those patients with sufficient soft-tissue integrity. In general, patients with inflammatory disorders, collateral ligament insufficiency, and acute or chronic PIPJ septic arthritis are poor candidates for PIPJ surface replacement arthroplasty.

Trimed Fixation System for Displaced Fractures of the Distal Radius

To study the functional outcome of displaced distal radius fractures treated by open reduction and internal fixation with the use of fragment-specific fixation. Fifteen consecutive displaced distal radius fractures (5 extra-articular and 10 intra-articular) were treated using the Trimed distal radius fixation system (Trimed, Valencia, CA). Radiographic assessment and range of motion of the affected wrist were evaluated postoperatively. Functional outcomes were evaluated with use of the Disabilities of the Arm, Shoulder, and Hand questionnaire and the Gartland and Werley scoring system. The mean follow-up was 11 months. The patients initiated controlled passive and active motion exercises during the first week. The mean score on the Disabilities of the Arm, Shoulder, and Hand questionnaire was 16 points. The mean return to work was 12 weeks. The functional outcome was 80% excellent or good by the Gartland and Werley scoring system for intra-articular fractures and 80% excellent for extra-articular fractures. Range of active motion in intra-articular fractures was measured 60 degrees wrist extension, 64 degrees flexion, 65 degrees pronation, and 70 degrees supination, and for extra-articular fractures, 75 degrees extension, 70 degrees flexion, 80 degrees pronation, and 75 degrees supination. There was failure of fixation with loss of the reduction that was achieved at the time of operation in one patient. Fragment-specific fixation of unstable distal radius fractures using the Trimed system appears to be effective. Anatomic reduction, earlier range of motion, and improved functional results can be achieved using low-profile implants.

Displaced Three- and Four-Part Proximal Humerus Fractures: Evaluation and Management

Three- and four-part fractures are the most severe injuries in the spectrum of fractures of the proximal humerus. Despite the shortcomings of the currently available imaging techniques, fracture displacement remains an important principle in guiding management. As a result, increasing emphasis has been placed on the use of Neer's criteria in intraoperative decision making. Patients with four-part fractures with valgus impaction of the head fragment should be treated with limited open reduction and minimal internal fixation, as the blood supply to the humeral head is better preserved than with other fracture patterns and the potential for osteonecrosis is less. In the case of displaced three- and four-part fractures, the physiologic age and bone quality also help guide treatment selection. In young patients with good bone quality, attempts to preserve the humeral head by meticulous handling of soft tissues and the use of low-profile implants to secure fracture fragments is recommended. Vertical fixation alone with Rush rods in patients with poor bone quality and in those with four-part fractures is no longer considered adequate and should not be used. For selected patients with three-part fractures and satisfactory bone quality, fixation with Ender rods and tension-band wiring may be appropriate. Elderly patients and those with poor bone quality have a greater risk of loss of reduction after open reduction and internal fixation, and the current consensus is that early hemiarthroplasty is the appropriate treatment. Late reconstruction necessitated by malunion and soft-tissue contracture is technically difficult, and the outcome is less favorable. The outcome of treatment of three- and four-part fractures is dependent on the surgeon's ability to analyze the fracture pattern and execute appropriate techniques to restore anatomy and function. The use of cement for prosthetic fixation and rigorous attention to tuberosity stabilization and anatomic reduction are two factors that will optimize outcome. Adequate pain relief after hemiarthroplasty has been consistently demonstrated, but return of motion and function is less predictable.

Pilon Fractures

One hundred seven pilon fractures in 107 patients were treated according to a staged prospective protocol. All pilon fractures were stabilized immediately by the application of calcaneal traction. Open fractures or fractures in patients with multiple injuries were stabilized with traveling traction that was applied in the operating room. A distraction computed tomography scan was obtained before definitive treatment. Treatment groups were based on the degree of soft tissue compromise. Forty-one patients with Tscherne Grade 0 or Grade I injuries underwent open reduction and internal fixation (open plating) using contemporary techniques and low-profile implants. Sixty-four patients with Tscherne Grade II and Grade III closed injuries and all patients with open fractures underwent definitive treatment with limited open reduction and stabilization using small wire circular external fixators. Clinical and radiographic evaluations were performed at an average 4.9 years after injury. For all fracture types (AO classification), 81% of the patients who were treated with external fixation and 75% of the patients who were treated with open plating had good or excellent results. For severe fracture patterns (Type C), patients in both groups had significantly poorer results than patients with Types A and B fractures. The patients in the open plating group had a significantly higher rate of nonunion, malunion, and severe wound complications compared with the patients who received external fixation for Type C fracture patterns. Because of the increased incidence of bony and soft tissue complications when treating open or closed Type C fractures, use of limited exposures and stabilization with small wire circular external fixators is recommended.