Kevin C. Baker

Short versus long intramedullary nails for treatment of intertrochanteric femur fractures (OTA 31-A1 and A2).

Objectives: The purpose of this study was to compare blood loss and operative times associated with long versus short intramedullary nails for intertrochanteric fracture fixation and rate of periprosthetic fracture. Design: A retrospective study. Setting: Level 1 trauma center. Patients: One hundred ninety-four patients with an intertrochanteric fracture (AO/OTA class 31-A1 and A2) and low-energy mechanism of injury treated by 1 of 4 fellowship-trained orthopaedic traumatologists. Intervention: Short versus long intramedullary nail. Methods: Medical records were reviewed for age, gender, estimated blood loss (EBL), transfusion rate, operative time, length of stay, and incidence of periprosthetic fracture. Variables were statistically compared between long and short intramedullary nails, with statistical significance at P < 0.05. Results: The average EBL (135.5 ± 91.9 mL) and transfusion rate (57.1%) for long nails were found to be significantly greater (P = 0.002) than the EBL (92.6 ± 47.2 mL) and transfusion rate (40.2%) for short nails. Average operative time was also found to be significantly greater (P < 0.001) for long (56.8 ± 19.4 minutes) than for short (44.0 ± 10.7 minutes) intramedullary nail procedures. The overall incidence of periprosthetic fracture was 0.5%, one patient with initial treatment of a long intramedullary nail. Conclusions: Statistically significant lower operative time, EBL, and transfusion rate were found in this study for short intramedullary nails. There were no differences seen in length of stay or periprosthetic fracture. The incidence of periprosthetic fracture was very low in both cohorts. Further study with greater statistical power is needed. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Single- versus multilevel fusion for single-level degenerative spondylolisthesis and multilevel lumbar stenosis: four-year results of the spine patient outcomes research trial.

Study Design. A subanalysis study. Objective. To compare surgical outcomes and complications of multilevel decompression and single-level fusion with multilevel decompression and multilevel fusion for patients with multilevel lumbar stenosis and single-level degenerative spondylolisthesis (DS). Summary of Background Data. In patients with DS who are treated surgically, decompression and fusion provide a better clinical outcome than decompression alone. Surgical treatment for multilevel lumbar stenosis and DS typically includes decompression and fusion of the spondylolisthesis segment and decompression with or without fusion for the other stenotic segments. To date, no study has compared the results of these 2 surgical options for single-level DS with multilevel stenosis. Methods. The results from a multicenter randomized and observational study, the Spine Patient Outcomes Research Trial comparing multilevel decompression and single-level fusion and multilevel decompression and multilevel fusion for spinal stenosis with spondylolisthesis, were analyzed. The primary outcome measures were the bodily pain and physical function scales of the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36) and the modified Oswestry Disability Index at 1, 2, 3, and 4 years postoperatively. Secondary analysis consisted of stenosis bothersomeness index, low back pain bothersomeness, leg pain, patient satisfaction, and self-rated progress. Results. Overall, 207 patients were enrolled for the study, 130 had multlilevel decompression with 1 level fusion and 77 patients had multilevel decompression and multilevel fusion. For all primary and secondary outcome measures, there were no statistically significant differences in surgical outcomes between the 2 surgical techniques. However, operative time and intraoperative blood loss were significantly higher in the multilevel fusion group. Conclusion. Decompression and single-level fusion and decompression and multilevel fusion provide similar outcomes in patients with multilevel lumbar stenosis and single-level DS.

Biomimetic calcium phosphate coatings as bone morphogenetic protein delivery systems in spinal fusion.

BACKGROUND CONTEXT Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to enhance spinal fusion rates. Case reports of soft-tissue swelling, ectopic bone formation, and osteolysis have recently surfaced. It is hypothesized that incorporation of rhBMP-2 within a calcium phosphate (CaP) coating may help to localize delivery and mitigate these complications. PURPOSE To compare the characteristics of posterolateral fusion between rabbits receiving rhBMP-2 delivered via physical adsorption to a collagen sponge or rhBMP-2 incorporated within the physical structure of a CaP coating on a collagen sponge. STUDY DESIGN/SETTING New Zealand white rabbit model of posterolateral lumbar fusion at L5-L6. METHODS Eighteen (18) New Zealand white rabbits underwent posterolateral spinal fusion at L5-L6. Rabbits received bilateral collagen sponges that were either coated with CaP (n=3), coated with CaP and dipped in rhBMP-2 (n=3), coated with a hybrid CaP-rhBMP-2 film (n=6), or coated with a hybrid CaP-rhBMP-2 film and dipped in rhBMP-2 (n=6). Animals were followed weekly with radiographs and were sacrificed at 6 weeks. Fusion masses were further characterized by manual palpation, computed tomography, and histology. RESULTS Radiographic evaluation showed that animals in Group 3 (incorporated BMP) fused at 4 weeks, whereas animals in Group 2 (adsorbed BMP) and Group 4 (incorporated and adsorbed BMP) fused by 6 weeks. Animals that received rhBMP-2 physically adsorbed to the collagen sponge showed extension of the fusion mass beyond the L5-L6 level in 56% of cases and bone resorption in 78%. Histology of fusion masses showed mature bone formation in animals belonging to Groups 2, 3, and 4 and extensive osteoclast recruitment in animals belonging to Groups 2 and 4. CONCLUSIONS Delivery of rhBMP-2 via incorporation within CaP coatings results in increased rates of radiographic fusion. The burst release profile of rhBMP-2 adsorbed to surfaces, although effective in achieving fusion, may result in increased osteoclast recruitment.

Fracture of an Alumina Femoral Head Used in Ceramic-on-Ceramic Total Hip Arthroplasty

A case report regarding the fracture of an alumina ceramic femoral head used in ceramic-on-ceramic total hip arthroplasty is presented. The patient, who was seen in the emergency room with pain, grinding, and instability in the hip immediately after a slip-without-fall event, also reported having fallen from a height of 8 ft 6 months earlier. Characterization of the alumina fracture surfaces by light and scanning electron microscopy suggests that the previous fall may have favored the nucleation and growth of subcritical cracks in the ceramic, which lead to fracture during the slip-without-fall event. The case report addresses the significance of impact trauma on the structural integrity of ceramic materials, which should not be ignored by patient or physician regardless of perceived severity.

Rehabilitation following arthroscopic rotator cuff repair: a review of current literature.

&NA; Physical rehabilitation following arthroscopic rotator cuff repair has conventionally involved a 4‐ to 6‐week period of immobilization; there are two schools of thought regarding activity level during this period. Some authors encourage early, more aggressive rehabilitation along with the use of a continuous passive motion device; others propose later, more conservative rehabilitation. Although some studies report trends in improved early range of motion, pain relief, and outcomes scores with aggressive rehabilitation following rotator cuff repair, no definitive consensus exists supporting a clinical difference resulting from rehabilitation timing in the early stages of healing. Rehabilitation timing does not affect outcomes after 6 to 12 months postoperatively. Given the lack of information regarding which patient groups benefit from aggressive rehabilitation, individualized patient care is warranted.

Failure of Coracoclavicular Artificial Graft Reconstructions From Repetitive Rotation

PURPOSE To assess how suture type and suture construct in an augmented Weaver-Dunn reconstruction affect coracoclavicular sling failure and rotary stability. METHODS Fifteen cadaveric shoulders were tested in rotation about the long axis of the clavicle with 10 lb of simulated arm weight. The clavicle was rotated 50 degrees about its long axis, and the applied torque was recorded. Next, modified Weaver-Dunn reconstruction was conducted. Two types of coracoclavicular sling (opposed drill holes through the clavicle and complete loop around the clavicle) were tested by use of 3 different sutures (FiberWire [Arthrex, Naples, FL], Mersilene tape [Ethicon, Somerville, NJ], and braided polydioxanone [PDS] [Ethicon]). For each sling-suture combination, the joint was retested over 50 degrees of rotation and then cycled over 40 degrees of rotation for 15,000 cycles or until failure. RESULTS After modified Weaver-Dunn reconstruction with either sling construct, mean torque over 50 degrees of acromioclavicular rotation was significantly reduced in posterior (P < .0001) and anterior (P < .0001) rotation, with any suture material tested. When the coracoclavicular sling was placed through opposed drill holes, no wear to the bone or suture was observed. When the sling material was looped around the clavicle, FiberWire and PDS resulted in abrasion of soft tissue and periosteum. In all cases sawing motion between bone and suture was observed at the coracoid. The FiberWire itself failed at a mean of 8,213 cycles. Some wear was noted in the Mersilene tape. PDS suture showed no wear. CONCLUSIONS In a cadaveric model of modified Weaver-Dunn reconstruction, a coracoclavicular suture loop was used to augment coracoacromial ligament transfer. Suture loops secured around the entire clavicle were shown to contribute to increased abrasive wear. Securing suture loops through opposed drill holes in the clavicle resulted in decreased abrasive wear. CLINICAL RELEVANCE Proper selection of suture type and suture construct may affect the failure rate of augmented Weaver-Dunn reconstructions.

Early failure of bioabsorbable anterior cervical fusion plates: case report and failure analysis.

Study Design Case report with forensic failure analysis. Objective To determine the failure modes of 3 explanted 70:30 PLDLA Mystique (Medtronic Sofamor Danek, Memphis, TN) graft containment plates retrieved from revision surgery for early device failure. Summary of Background Data To reduce the problems of stress-shielding and radiopacity associated with metallic systems, bioabsorbable polymers have been used in anterior cervical discectomy and fusion procedures. Degradation of mechanical properties in vivo is a major concern when using bioabsorbable systems. Three of 6 patients who underwent anterior cervical discectomy with instrumented fusion, using Mystique graft containment systems experienced early failure requiring revision to alternate hardware. Methods Devices were retrieved after failure and analyzed by light microscopy and environmental scanning electron microscopy. Simulations were performed with an unused plating system to induce damage for comparison with the retrieved devices. A detailed case review was performed to identify possible sources of extraordinary loading or damage. Results One plating system failed at 6 weeks postimplantation due to fatigue fracture of the screws. Crack initiation sites were identified at the interface of the thread root and mold line of the screw. Another plating system failed at 16 weeks postimplantation due to the coalescence of radial microcracking between holes in the plate, leading to catastrophic failure of the plate. The final plating system failed during the implantation surgery, when the screw fractured in torsion. Conclusions Stress concentrations at the screw head-shaft interface and thread-shaft interface reduce the fatigue performance of bioabsorbable screws. Hydrolysis of the polymer may also play a role in the reduction of resistance to crack initiation and propagation.

Cement augmentation in vertebral burst fractures

As a result of axial compression, traumatic vertebral burst fractures disrupt the anterior column, leading to segmental instability and cord compression. In situations with diminished anterior column support, pedicle screw fixation alone may lead to delayed kyphosis, nonunion, and hardware failure. Vertebroplasty and kyphoplasty (balloon-assisted vertebroplasty) have been used in an effort to provide anterior column support in traumatic burst fractures. Cited advantages are providing immediate stability, improving pain, and reducing hardware malfunction. When used in isolation or in combination with posterior instrumentation, these techniques theoretically allow for improved fracture reduction and maintenance of spinal alignment while avoiding the complications and morbidity of anterior approaches. Complications associated with cement use (leakage, systemic effects) are similar to those seen in the treatment of osteoporotic compression fractures; however, extreme caution must be used in fractures with a disrupted posterior wall.

Characterization of daptomycin-loaded antibiotic cement.

Antibiotics are commonly mixed with polymethylmethacrylate (PMMA) cement to suppress severe periprosthetic infections associated with total joint arthroplasty. The relationship between antibiotic concentration and the resulting elution kinetics remains unclear. The purpose of this study was to characterize the release of daptomycin from PMMA cement and the subsequent effects on mechanical properties.Varying concentrations of daptomycin and tobramycin were vacuum mixed in commercially available PMMA and subjected to an in vitro elution period. High-performance liquid chromatography was used to quantify the concentration of the amount of daptomycin eluted at predetermined time points. Samples were subjected to compressive loading to analyze the effect of antibiotic concentration on cement mechanical properties. Daptomycin elution increased when initial tobramycin concentration was increased. Furthermore, the addition of antibiotics increased the compressive strength of the cement in the postelution period. The binary addition of tobramycin with daptomycin antibiotics modifies the elution and mechanical properties of PMMA bone cement. Based on the findings of our study, 2 g of daptomycin and 3.6 g of tobramycin per 40-g packet of cement should be used to promote daptomycin elution without sacrificing PMMA mechanical properties.

Lumbar pseudarthrosis: a review of current diagnosis and treatment

OBJECT Failed solid bony fusion, or pseudarthrosis, is a well-known complication of lumbar arthrodesis. Recent advances in radiographic technology, biologics, instrumentation, surgical technique, and understanding of the local biology have all aided in the prevention and treatment of pseudarthrosis. Here, the current literature on the diagnosis and management of lumbar pseudarthroses is reviewed. METHODS A systematic literature review was conducted using the MEDLINE and Embase databases in order to search for the current radiographie diagnosis and surgical treatment methods published in the literature (1985 to present). Inclusion criteria included: 1) published in English; 2) level of evidence I-III; 3) diagnosis of degenerative lumbar spine conditions and/or history of lumbar spine fusion surgery; and 4) comparative studies of 2 different surgical techniques or comparative studies of imaging modality versus surgical exploration. RESULTS Seven studies met the inclusion criteria for current radiographie imaging used to diagnose lumbar pseudarthrosis. Plain radiographs and thin-cut CT scans were the most common method for radiographie diagnosis. PET has been shown to be a valid imaging modality for monitoring in vivo active bone formation. Eight studies compared the surgical techniques for managing and preventing failed lumbar fusion. The success rates for the treatment of pseudarthrosis are enhanced with the use of rigid instrumentation. CONCLUSIONS Spinal fusion rates have improved secondary to advances in biologies, instrumentation, surgical techniques, and understanding of local biology. Treatment of lumbar pseudarthrosis includes a variety of surgical options such as replacing loose instrumentation, use of more potent biologies, and interbody fusion techniques. Prevention and recognition are important tenets in the algorithm for the management of spinal pseudarthrosis.