3D printing of multilayered scaffolds for rotator cuff tendon regeneration.

Repairing massive rotator cuff tendon defects remains a challenge due to the high retear rate after surgical intervention. 3D printing has emerged as a promising technique that enables the fabrication of engineered tissues with heterogeneous structures and mechanical properties, as well as controllable microenvironments for tendon regeneration. In this study, we developed a new strategy for rotator cuff tendon repair by combining a 3D printed scaffold of polylactic-co-glycolic acid (PLGA) with cell-laden collagen-fibrin hydrogels. We designed and fabricated two types of scaffolds: one featuring a separate layer-by-layer structure and another with a tri-layered structure as a whole. Uniaxial tensile tests showed that both types of scaffolds had improved mechanical properties compared to single-layered PLGA scaffolds. The printed scaffold with collagen-fibrin hydrogels effectively supported the growth, proliferation, and tenogenic differentiation of human adipose-derived mesenchymal stem cells. Subcutaneous implantation of the multilayered scaffolds demonstrated their excellent in vivo biocompatibility. This study demonstrates the feasibility of 3D printing multilayered scaffolds for application in rotator cuff tendon regeneration.

Electrospun thymosin Beta-4 loaded PLGA/PLA nanofiber/ microfiber hybrid yarns for tendon tissue engineering application.

Microfiber yarns (MY) have been widely employed to construct tendon tissue grafts. However, suboptimal ultrastructure and inappropriate environments for cell interactions limit their clinical application. Herein, we designed a modified electrospinning device to coat poly(lactic-co-glycolic acid) PLGA nanofibers onto polylactic acid (PLA) MY to generate PLGA/PLA hybrid yarns (HY), which had a well-aligned nanofibrous structure, resembling the ultrastructure of native tendon tissues and showed enhanced failure load compared to PLA MY. PLGA/PLA HY significantly improved the growth, proliferation, and tendon-specific gene expressions of human adipose derived mesenchymal stem cells (HADMSC) compared to PLA MY. Moreover, thymosin beta-4 (Tß4) loaded PLGA/PLA HY presented a sustained drug release manner for 28 days and showed an additive effect on promoting HADMSC migration, proliferation, and tenogenic differentiation. Collectively, the combination of Tß4 with the nano-topography of PLGA/PLA HY might be an efficient strategy to promote tenogenesis of adult stem cells for tendon tissue engineering.

Fingerbreadths Rule in Determining the Safe Zone of the Radial Nerve and Posterior Interosseous Nerve for a Lateral Elbow Approach: An Anatomic Study.

INTRODUCTION: The purpose of this study was to investigate whether a safe zone rule could be applied to prevent iatrogenic injuries to the radial nerve (RN); and determine whether there is a relationship between the diameter of the radial head and capitellum and the distance of the posterior interosseous nerve (PIN) to the radiocapitellar joint. METHODS: Ten fresh-frozen cadaveric specimens were used to measure the distances between the RN and the lateral epicondyle; the PIN and the radiocapitellar joint; the lateral epicondyle and the PIN as it crossed the ulnohumeral joint; the diameter of the radial head; the width of the capitellum; and the fingerbreadths of the specimens. RESULTS: Four fingerbreadths determined a safe zone between the lateral epicondyle and the RN proximally at the point at which it pierced the intermuscular septum and the mid-lateral portion of the humeral shaft. Two fingerbreadths provided a safe zone for the PIN from the radiocapitellar joint to the midpoint of the axis of the radius only with the forearm in pronation. CONCLUSION: A four-finger rule, two-finger rule, and radial head diameter or capitellum size may predict a safe zone for the RN and PIN except for the segment of the nerve where it crosses the anterior cortex of either the humerus or radius. LEVEL OF EVIDENCE: Preclinical cadaveric study.

Isolated Partial Intra-Articular Volar Ulnar Fractures of the Distal Radius: The Tetrahedron Variant.

PURPOSE: The aim of this study was to assess the treatment and complications of a distinct type of partial intra-articular distal radius fracture. METHODS: Seven patients treated by the senior author between 2008 and 2013 for a partial intra-articular distal radius fracture with isolated involvement of the volar lunate facet were included. All fragments had the distinctive shape of a triangular-base pyramid (tetrahedron) extending from the metaphysis distally. All fractures were preoperatively assessed with computed tomography (CT) scans. Patients underwent surgical treatment using a standard flexor carpi radialis approach (2 patients) or a volar ulnar approach (5 patients) and were followed postoperatively for a minimum of 12 months. RESULTS: Patient age ranged from 33 to 66 years. On average, fragments measured 34 ± 6 mm in length (range, 27-43 mm) and were 48% as wide as the distal radius (range, 40% to 56%) and 58% as deep as the anterior-posterior dimension of the lesser sigmoid notch (range, 33% to 83%). Loss of reduction requiring revision surgery occurred at 4 weeks in 1 patient who underwent internal fixation through the flexor carpi radialis approach. The remaining cases healed uneventfully. At the final follow-up, all, except the patient requiring revision surgery, had a painless wrist. Average total wrist motion measured 87% of the opposite side. Radiographic healing with anatomic wrist alignment was observed in all except the patient requiring revision. This patient had persistent joint subluxation. The remaining patients all achieved good or excellent functional outcomes. CONCLUSIONS: Isolated tetrahedron volar lunate facet fractures of the distal radius are rare. In our experience, the use of a volar ulnar approach leads to satisfactory fixation and outcomes, yielding excellent radiographic and clinical outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Effect of scaffold morphology and cell co-culture on tenogenic differentiation of HADMSC on centrifugal melt electrospun poly (L­lactic acid) fibrous meshes.

Engineered tendon grafts offer a promising alternative for grafting during the reconstruction of complex tendon tears. The tissue-engineered tendon substitutes have the advantage of increased biosafety and the option to customize their biochemical and biophysical properties to promote tendon regeneration. In this study, we developed a novel centrifugal melt electrospinning (CME) technique, with the goal of optimizing the fabrication parameters to generate fibrous scaffolds for tendon tissue engineering. The effects of CME processing parameters, including rotational speed, voltage, and temperature, on fiber properties (i.e. orientation, mean diameter, and productivity) were systematically investigated. By using this solvent-free and environmentally friendly method, we fabricated both random and aligned poly (L-lactic acid) (PLLA) fibrous scaffolds with controllable mesh thickness. We also investigated and compared their morphology, surface hydrophilicity, and mechanical properties. We seeded human adipose derived mesenchymal stem cells (HADMSC) on various PLLA fibrous scaffolds and conditioned the constructs in tenogenic differentiation medium for up to 21 days, to investigate the effects of fiber alignment and scaffold thickness on cell behavior. Aligned fibrous scaffolds induced cell elongation and orientation through a contact guidance phenomenon and promoted HADMSC proliferation and differentiation towards tenocytes. At the early stage, thinner scaffolds were beneficial for HADMSC proliferation, but the scaffold thickness had no significant effects on cell proliferation for longer-term cell culture. We further co-seeded HADMSC and human umbilical vein endothelial cells (HUVEC) on aligned PLLA fibrous mats and determined how the vascularization affected HADMSC tenogenesis. We found that co-cultured HADMSC-HUVEC expressed more tendon-related markers on the aligned fibrous scaffold. The co-culture systems promoted in vitro HADMSC differentiation towards tenocytes. These aligned fibrous scaffolds fabricated by CME technique could potentially be utilized to repair and regenerate tendon defects and injuries with cell co-culture and controlled vascularization.

Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation.

Non-woven nanofibrous scaffolds have been developed for tendon graft application by using electrospinning strategies. However, electrospun nanofibrous scaffolds face some obstacles and limitations, including suboptimal scaffold structure, weak tensile and suture-retention strengths, and compact structure for cell infiltration. In this work, a novel nanofibrous, woven biotextile, fabricated based on electrospun nanofiber yarns, was implemented as a tissue engineered tendon scaffold. Based on our modified electrospinning setup, polycaprolactone (PCL) nanofiber yarns were fabricated with reproducible quality, and were further processed into plain-weaving fabrics interlaced with polylactic acid (PLA) multifilaments. Nonwoven nanofibrous PCL meshes with random or aligned fiber structures were generated using typical electrospinning as comparative counterparts. The woven fabrics contained 3D aligned microstructures with significantly larger pore size and obviously enhanced tensile mechanical properties than their nonwoven counterparts. The biological results revealed that cell proliferation and infiltration, along with the expression of tendon-specific genes by human adipose derived mesenchymal stem cells (HADMSC) and human tenocytes (HT), were significantly enhanced on the woven fabrics compared with those on randomly-oriented or aligned nanofiber meshes. Co-cultures of HADMSC with HT or human umbilical vein endothelial cells (HUVEC) on woven fabrics significantly upregulated the functional expression of most tenogenic markers. HADMSC/HT/HUVEC tri-culture on woven fabrics showed the highest upregulation of most tendon-associated markers than all the other mono- and co-culture groups. Furthermore, we conditioned the tri-cultured constructs with dynamic conditioning and demonstrated that dynamic stretch promoted total collagen secretion and tenogenic differentiation. Our nanofiber yarn-based biotextiles have significant potential to be used as engineered scaffolds to synergize the multiple cell interaction and mechanical stimulation for promoting tendon regeneration. STATEMENT OF SIGNIFICANCE: Tendon grafts are essential for the treatment of various tendon-related conditions due to the inherently poor healing capacity of native tendon tissues. In this study, we combined electrospun nanofiber yarns with textile manufacturing strategies to fabricate nanofibrous woven biotextiles with hierarchical features, aligned fibrous topography, and sufficient mechanical properties as tendon tissue engineered scaffolds. Comparing to traditional electrospun random or aligned meshes, our novel nanofibrous woven fabrics possess strong tensile and suture-retention strengths and larger pore size. We also demonstrated that the incorporation of tendon cells and vascular cells promoted the tenogenic differentiation of the engineered tendon constructs, especially under dynamic stretch. This study not only presents a novel tissue engineered tendon scaffold fabrication technique but also provides a useful strategy to promote tendon differentiation and regeneration.

Total Elbow Arthroplasty for Distal Humeral Fractures: A Ten-Year-Minimum Follow-up Study.

BACKGROUND: Total elbow arthroplasty is commonly considered for elderly patients with comminuted distal humeral fractures. Satisfactory short-term outcomes have been reported, but long-term outcomes are unknown. Our purpose was to assess the long-term outcomes of total elbow arthroplasty after distal humeral fracture and to determine differences between elbows with or without inflammatory arthritis at the time of fracture. METHODS: Forty-four total elbow arthroplasties were performed after distal humeral fracture; those patients were followed for a minimum of 10 years and were evaluated with regard to pain, motion, Mayo Elbow Performance Scores, complications, and reoperations. The outcomes in elbows with and without inflammatory arthritis were compared. Kaplan-Meier survivorship analysis was performed. RESULTS: Total elbow arthroplasty provided good pain relief and motion; the mean visual analog scale for pain was 0.6, the mean flexion was 123°, and the mean loss of extension was 24°. The mean Mayo Elbow Performance Score was 90.5 points, with 3 patients scoring <75 points. Five elbows (11%) developed deep infection, treated surgically with component retention (3 acute) or resection (2 chronic). Implant revision or resection was performed in 8 elbows (18%): 3 for infections (1 reimplantation and 2 resections), 3 for ulnar loosening (associated with periprosthetic fracture in 1), and 2 for ulnar component fractures. Additional periprosthetic fractures were observed in 5 elbows. The survival rates for elbows with rheumatoid arthritis were 85% at 5 years and 76% at 10 years, and the survival rates for elbows without rheumatoid arthritis were 92% at both 5 and 10 years. The most relevant risk factor for revision was male sex (hazard ratio, 12.6 [95% confidence interval, 1.7 to 93.6]). CONCLUSIONS: Selective use of total elbow arthroplasty to treat fractures of the distal part of the humerus for infirm, less active older patients and patients with inflammatory arthritis has acceptable longevity in surviving patients, but at the cost of a number of major complications. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Change in the Distance From the Axillary Nerve to the Glenohumeral Joint With Shoulder External Rotation or Abduction Position.

BACKGROUND: This study investigated whether axillary nerve (AN) distance to the inferior border of the humeral head and inferior glenoid would change while placing the glenohumeral joint in different degrees of external rotation and abduction. METHODS: A standard deltopectoral approach was performed on 10 fresh-frozen cadaveric specimens. The distance between AN and the inferior border of the humeral head and inferior glenoid while placing the shoulder in 0°, 45°, and 90° of external rotation or abduction was measured. Continuous variables for changes in AN position were compared with paired 2-tailed Student t test. RESULTS: The mean distance between the AN and the humeral head with the shoulder in 0°, 45°, and 90° of external rotation and 0° of abduction was 13.77 mm (SD 4.31), 13.99 mm (SD 4.12), and 16.28 mm (SD 5.40), respectively. The mean distance between the AN and glenoid with the shoulder in 0°, 45°, and 90° of external rotation was 16.33 mm (SD 3.60), 15.60 mm (SD 4.19), and 16.43 (SD 5.35), respectively. The mean distance between the AN and the humeral head with the shoulder in 0°, 45°, and 90° of abduction and 0° of external rotation was 13.76 mm (SD 4.31), 10.68 mm (SD 4.19), and 3.81 mm (SD 3.08), respectively. The mean distance between the AN and glenoid with the shoulder in 0°, 45°, and 90° of abduction was 16.33 mm (SD 3.60), 17.66 mm (SD 5.80), and 12.44 mm (SD 5.57), respectively. CONCLUSIONS: The AN position relative to the inferior aspect of the glenohumeral joint does not significantly change despite position of external rotation. Increasing shoulder abduction over 45° decreases the distance from the glenohumeral joint to the AN and should be avoided.

Effects of Hydroxyapatite and Hypoxia on Chondrogenesis and Hypertrophy in 3D Bioprinted ADMSC Laden Constructs.

Hydrogel-based cartilage tissue engineering strategies require the induction and long-term maintenance of adipose derived mesenchymal stem cells (ADMSC) into a stable chondrogenic phenotype. However, ADMSC exhibit the tendency to undergo hypertrophic differentiation, rather than forming permanent hyaline cartilage phenotype changes. This may hinder their implementation in articular cartilage regeneration, but may allow the possibility for bone and bone to soft tissue interface repair. In this study, we examined the effects of hydroxyapatite (HAp) on the chondrogenesis and hypertrophy of ADMSC within bioprinted hyaluronic acid (HA)-based hydrogels. We found that a small amount of HAp (∼10% of polymer concentration) promoted both chondrogenic and hypertrophic differentiation of ADMSC. Increased HAp contents promoted hypertrophic conversion and early osteogenic differentiation of encapsulated ADMSC. Subsequently, ADMSC-laden, stratified constructs with nonmineralized and mineralized layers (i.e., HA based and HA-HAp based) were 3D bioprinted. The constructs were conditioned in chondrogenic medium in either a normoxic or hypoxic environment for 8 weeks to assess the effects of oxygen tension on ADMSC differentiation and interface integration. We further implanted the bioprinted constructs subcutaneously into nude mice for 4 weeks. It was found that hypoxia partially inhibited hypertrophic differentiation by significantly down-regulating the expression of COL10A1, ALP, and MMP13. In addition, hypoxia also suppressed spontaneous calcification of ADMSC and promoted interface integration. This study demonstrates that both HAp content and hypoxia are important to mediate chondrogenesis, hypertrophy, and endochondral ossification of ADMSC. An optimized recipe and condition will allow for 3D bioprinting of multizonal grafts with integrated hard tissue and soft tissue interfaces for the treatment of complex orthopedic defects.

Revision of failed humeral head resurfacing arthroplasty.

PURPOSE: The purpose of this study is to assess the outcomes of a consecutive series of patients who underwent revision surgery after humeral head resurfacing (HHR). Our joint registry was queried for all patients who underwent revision arthroplasty for failed HHR at our institution from 2005 to 2010. Eleven consecutive patients (average age 54 years; range 38-69 years) that underwent revision of 11 resurfacing arthroplasties were identified. The primary indication for resurfacing had been osteoarthritis in six, glenoid dysplasia in two, a chondral lesion in two, and postinstability arthropathy in one patient. The indication for revision was pain in 10 and infection in one patient. Seven patients had undergone an average of 1.9 surgeries prior to resurfacing (range 1-3). MATERIALS AND METHODS: All patients were revised to stemmed arthroplasties, including one hemiarthroplasty, two reverse, and eight anatomic total shoulder arthroplasties at a mean 33 months after primary resurfacing (range 10-131 months). A deltopectoral approach was used in seven patients; four patients required an anteromedial approach due to severe scarring. Subscapularis attenuation was found in four cases, two of which required reverse total shoulder arthroplasty. Bone grafting was required in one glenoid and three humeri. RESULTS: At a mean follow-up of 3.5 years (range 1.6-6.9 years), modified Neer score was rated as satisfactory in five patients and unsatisfactory in six. Abduction and external rotation improved from 73° to 88° (P = 0.32) and from 23° to 32° (P = 0.28) respectively. Reoperation was required in two patients, including one hematoma and one revision for instability. CONCLUSION: Outcomes of revision of HHR arthroplasty in this cohort did not improve upon those reported for revision of stemmed humeral implants. A comparative study would be required to allow for definitive conclusions to be made.

Locked plating versus cephalomedullary nailing of unstable intertrochanteric femur fractures.

BACKGROUND: Proximal femur locking plates (PFLP) have received increased attention as an alternative for the treatment of proximal femur fractures. However, recent clinical data on these implants has raised concern about higher than expected failure rates. QUESTION/PURPOSE: The purpose of the present study was to compare outcomes of unstable pertrochanteric femur fractures (AO/OTA 31A3) treated at a level-1 trauma center using either PFLP or cephalomedullary nailing (CMN). PATIENTS AND METHODS: Sixty-two patients (31 PFLP and 31 CMN, 55 % female, average age 63 years, range 21-94) with 64 OTA 31A3 fractures (32 PFLP and 32 CMN) treated between 2003 and 2007 were retrospectively reviewed. No differences were found with regard to gender, BMI, diabetes and time to surgery. RESULTS: One patient (5 %) in the CMN group underwent a reoperation (debridement with hardware removal), while eight PFLP patients (25 %) did (two debridements, two hardware removals, four nonunion repairs). One mechanical failure (5 %) occurred in the CMN group and 12 (38 %) in the PFLP group (p = 0.007). One nonunion (5 %) was observed in the CMN group, while 6 (19 %) occurred in the PFLP group. CONCLUSION: A higher rate of reoperation and mechanical failure can be expected for unstable intertrochanteric femur fracture when treated with PFLP than with CMN.

Fate of Patients With a "Surprise" Positive Culture After Nonunion Surgery.

OBJECTIVE: Review the impact of unexpected positive cultures from definitive surgery for nonunion regarding postoperative treatment and ultimate result. DESIGNS: Retrospective multicenter case series. SETTING: Three level-one trauma centers. PATIENTS: Six-hundred sixty-six consecutive nonunions were treated during the study period. Four-hundred fifty-three cases (68%) were considered at risk for indolent infection (prior open fracture, surgery, or infection) and had cultures taken at the time of definitive surgery. INTERVENTION: Intraoperative cultures during definitive operative treatment of nonunions. MAIN OUTCOME MEASUREMENT: The incidence of "surprise" positive cultures was determined, and the course of the patients was documented including the use of antibiotics, surgery performed, and the outcome regarding infection and union. RESULTS: Ninety-one (20%) cases had a surprise positive culture despite negative inflammatory markers. Most of bacteria isolated from the cultures were Staphylococcus species. Eight (9%) of the ninety-one cultures were considered probable contaminants and no antibiotics were given, 5 of these patients healed. The other 83 patients were treated with antibiotics, initially 66 (80%) healed and 12 (14%) remained infected. Eighty-two percent of patients with augmentation healed as compared with 86% of those not grafted. CONCLUSIONS: The treatment of nonunions is challenging, and in patients with a history of surgery or open fracture, we found that 20% had positive intraoperative cultures from the definitive surgery. We recommend intraoperative cultures for all patients undergoing revision surgery. The use of culture-specific antibiotics is justified based on the overall low rate of infection in this complex population and the high rate of chronic infection (25%) for those treated as contaminants. Patients may be counseled that a positive culture after nonunion surgery is a treatable problem but does increase the risk of infection and additional surgery as compared with those with a negative intraoperative culture. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Open surgical release for contractures of the elbow.

Compared with arthroscopic release, open release is more commonly used for the treatment of stiff elbow. Flexion is recovered by releasing posterior tethering soft-tissue structures and by removing anterior impingement between the coronoid and/or radial head and the distal humerus. Extension is improved by releasing anterior soft-tissue tethers and by removing impingement between the olecranon tip and the olecranon fossa. Open elbow release is most commonly performed via ligament-sparing approaches. Ulnar nerve identification and transposition is recommended in the presence of nerve dysfunction or when correction of significant loss of elbow flexion is anticipated. Long-term improvement in flexion and extension can be expected with proper patient selection. Less predictable results are obtained in adolescent patients and in those with underlying traumatic brain injury.

Anterior glenohumeral instability: a pathology-based surgical treatment strategy.

The glenohumeral joint is the most frequently dislocated major joint, and most cases involve an anterior dislocation. Young male athletes competing in contact sports are at especially high risk of recurrent instability. Surgical timing and selection of surgical technique continue to be debated. Full characterization of the injury requires an accurate history and physical examination. Diagnostic imaging assists in identifying the underlying anatomic lesions, which range from no discernible lesion to significant bone loss of the glenoid or humeral head and/or capsulolabral stretching or avulsion from the glenoid or humerus. Historically, open Bankart repair has been considered to be the standard method of managing capsulolabral injuries, but comparable results have been achieved with arthroscopic techniques. In the setting of anterior glenoid bone loss >20% of the articular surface, iliac crest bone grafting or coracoid transfer via the Bristow or Latarjet procedures has demonstrated satisfactory outcomes. Favorable results have been reported with bone grafting or remplissage for engaging Hill-Sachs lesions and those that affect >30% of the humeral circumference.

Low transcondylar fractures of the distal humerus: results of open reduction and internal fixation.

BACKGROUND: This study presents the outcomes of low transcondylar fractures of the distal humerus treated by open reduction and internal fixation. METHODS: Between 1996 and 2010, 263 distal humeral fractures were managed at our institution. Patients with a true low transcondylar fracture treated by open reduction and internal fixation were included. Fourteen patients form the basis of this study. Fracture fixation was achieved through a triceps-sparing approach, a triceps tongue, or an olecranon osteotomy. Internal fixation was performed with parallel plates, orthogonal plates, a single lateral plate, or a single medial plate. The clinical outcome was measured with pain levels, range of motion, and the Mayo Elbow Performance Score. Radiographs at latest follow-up were assessed for union, delayed union, nonunion, and hardware failure. RESULTS: At most recent follow-up, 11 patients had no pain, 2 had mild pain, and 1 had moderate pain. The mean Mayo Elbow Performance Score was 85. The mean arch of motion was 95°. Complications included nonunion, delayed union, wound complications, deep infection, and heterotopic ossification. DISCUSSION: Stable internal fixation of low transcondylar fractures is perceived as difficult to achieve because of the very small size of the distal fragment. However, the results of our study indicate that internal fixation of low transcondylar fractures of the distal humerus is associated with a high union rate and satisfactory clinical results. Elbow arthroplasty does not need to be considered for most patients with a low transcondylar distal humeral fracture.

Thirty and ninety-day reoperation rates after shoulder arthroplasty.

BACKGROUND: The purpose of the present study was to assess thirty and ninety-day reoperation rates after shoulder arthroplasty from 2000 to 2010. METHODS: Our institution's joint registry was queried to identify shoulder arthroplasties performed from January 2000 to December 2010. Data regarding patient demographics and the type of procedure were reviewed. Reoperations within thirty and ninety days after the index procedure were analyzed. During the eleven-year study period, 2305 primary arthroplasties (502 hemiarthroplasties, 1440 anatomic total shoulder arthroplasties, and 363 reverse total shoulder arthroplasties) and 518 revision arthroplasties (twenty-one hemiarthroplasties, 356 anatomic total arthroplasties, and 141 reverse arthroplasties) were performed. Fifty-four percent of patients were female; mean age was sixty-eight years (range, eighteen to ninety-seven years) and body mass index was 30.3 kg/m2 (range, 14.7 to 65.9 kg/m2). RESULTS: Reoperation was required within thirty days after fourteen primary arthroplasties (0.6%) and eight revision arthroplasties (1.5%); it was required within ninety days after thirty-two primary arthroplasties (1.4%) and thirteen revision arthroplasties (2.5%). The most frequent causes for reoperation after primary and revision arthroplasty were instability (n = 14 and 6) and infection (n = 13 and 3). The mean number of additional procedures required was 1.3 (range, one to four) for primary arthroplasties and 1.8 (range, one to three) for revision arthroplasties; 20% of patients undergoing reoperation required two or more additional procedures. Reoperations led to readmission in 82% of cases. CONCLUSIONS: Short-term reoperation after shoulder arthroplasty was infrequent. Wound complications and shoulder instability were the most frequent causes for reoperation. Reoperation was twice as frequent after revision surgery as after primary shoulder arthroplasty.

Risk factors for failure of locked plate fixation of distal femur fractures: an analysis of 335 cases.

OBJECTIVES: Locked plating has become a standard method to treat supracondylar femur fractures. Emerging evidence indicates that this method of treatment is associated with modest failure rates. The goals of this study were to determine risk factors for complications and to provide technical recommendations for locked plating of supracondylar femur fractures. DESIGN: Retrospective review. SETTING: Three level I or II trauma centers. PATIENTS/PARTICIPANTS: Three hundred twenty-six patients with 335 distal femur fractures (OTA 33A or C, 33% open) treated with lateral locked plates were studied. The average patient age was 57 years (range 17-97 years), 55% were women, 34% were obese, 19% were diabetic, and 24% were smokers. INTERVENTION: All patients were managed with open reduction internal fixation using a lateral distal femoral locked plate construct that included locked screws in the distal fragment and nonlocked, locked, or a combination of locked and nonlocked screws in the proximal fragment. MAIN OUTCOME MEASUREMENTS: Risk factors for reoperation to promote union, deep infection, and implant failure. RESULTS: After the index procedure, 64 fractures (19%) required reoperation to promote union, including 30 that had a planned staged bone grafting because of the metaphyseal defect after debridement of an open fracture. Independent risk factors for reoperation to promote union and deep infection included diabetes and open fracture. Risk factors for proximal implant failure included open fracture, smoking, increased body mass index, and shorter plate length. CONCLUSIONS: The identified risk factors for reoperation to promote union and complications included open fracture, diabetes, smoking, increased body mass index, and shorter plate length. Most factors are out of surgeon control but are useful when considering prognosis. Use of relatively long plates is a technical factor that can reduce risk for fixation failure. LEVEL OF EVIDENCE: Prognostic level II. See instructions for authors for a complete description of levels of evidence.

A comparison of more and less aggressive bone debridement protocols for the treatment of open supracondylar femur fractures.

OBJECTIVES: This study compared results of aggressive and nonaggressive debridement protocols for the treatment of high-energy, open supracondylar femur fractures after the primary procedure, with respect to the requirement for secondary bone grafting procedures, and deep infection. DESIGN: Retrospective review. SETTING: Level I and level II trauma centers. PATIENTS/PARTICIPANTS: Twenty-nine consecutive patients with high-grade, open (Gustilo types II and III) supracondylar femur fractures (OTA/AO 33A and C) treated with debridement and locked plating. INTERVENTION: Surgeons at 2 different level I trauma centers had different debridement protocols for open supracondylar femur fractures. One center used a more aggressive (MA) protocol in their patients (n = 17) that included removal of all devitalized bone and placement of antibiotic cement spacers to fill large segmental defects. The other center used a less aggressive (LA) protocol in their patients (n = 12) that included debridement of grossly contaminated bone with retention of other bone fragments and no use of antibiotic cement spacers. All other aspects of the treatment protocol at the 2 centers were similar: definitive fixation with locked plates in all cases, IV antibiotics were used until definitive wound closure, and weight bearing was advanced upon clinical and radiographic evidence of fracture healing. MAIN OUTCOME MEASUREMENTS: Healing after the primary procedure, requirement for secondary bone grafting procedures, and the presence of deep infection. RESULTS: Demographics were similar between included patients at each center with regard to age, gender, rate of open fractures, open fracture classification, mechanism, and smoking (P > 0.05). Patients at the MA center were more often diabetic (P < 0.05). Cement spacers to fill segmental defects were used more often after MA debridement (35% vs. 0%, P < 0.006), and more patients had a plan for staged bone grafting after MA debridement (71% vs. 8%, P < 0.006). Healing after the index fixation procedure occurred more often after LA debridement (92% vs. 35%, P < 0.003). There was no difference in infection rate between the 2 protocols: 25% with the LA protocol and 18% with the MA protocol (P = 0.63). All patients in both groups eventually healed and were without evidence of infection at an average of 1.8 years of follow-up. CONCLUSIONS: The degree to which bone should be debrided after a high-energy, high-grade, open supracondylar femur fracture is a matter of surgeon judgment and falls along a continuous spectrum. Based on the results of the current study, the theoretic trade-off between infection risk and osseous healing potential seems to favor an LA approach toward bone debridement in the initial treatment. LEVEL OF EVIDENCE: Therapeutic level III.

Unravelling the debate over orthopaedic trauma transfers: The sender's perspective.

INTRODUCTION: The increasing frequency of orthopaedic trauma patient transfers is an issue at the centre of the current orthopaedic "call crisis" that has the potential to inundate resources at tertiary care centres. Appropriateness of transfer has been investigated only from the perspective of receiving surgeons. This study investigates the suitability and reasons for orthopaedic trauma patient transfer from the viewpoint of transferring surgeons. METHODS: A questionnaire was e-mailed to a random sampling of 500 active members of the American Academy of Orthopaedic Surgeons and the Orthopaedic Trauma Association. Surgeons were split into three groups: senders of trauma patients (senders); orthopaedic traumatologists who receive transfers (traumatologist receivers); and other trauma transfer receivers that are not traumatologists (non-traumatologist receivers). The perceived complexity and appropriateness for transfer of eight virtual case scenarios were determined, along with the specific reasons mitigating transfer. RESULTS: 51 Senders, 90 traumatologist receivers, and 98 non-traumatologist receivers completed 239 surveys. There was agreement between groups for case complexity and appropriateness for transfer in five of eight case scenarios (p<0.05). Fracture complexity was cited as the primary reason for transfer by 28% of senders. However, just as common was a lack of resources at the sending hospital; OR equipment (18%), critical care services (18%), and inability to handle the immediacy of the case (7%) were also cited. Likelihood of uninsured status was the least common reason for transfer (1%). CONCLUSIONS: In most cases, both senders and receivers of orthopaedic trauma have similar viewpoints regarding fracture complexity and appropriateness of transfer. Sending surgeons cite case complexity and a lack of hospital resources as the primary reasons for patient transfer. Mandating increased call for orthopaedic surgeons at non-trauma centres without a concomitant increase in hospital resources is unlikely to substantially reduce unnecessary patient transfers to higher level facilities.

Mechanical failure after locking plate fixation of unstable intertrochanteric femur fractures.

OBJECTIVES: The aim of this study was analyze modes of mechanical failure in a consecutive cohort of patients and establish possible risk factors. DESIGN: This was a retrospective cohort study. SETTING: The study was conducted at an academic level-1 trauma center. PATIENTS: Twenty-nine patients (mean age 56 years, range 21-92; 45% males, 41% smokers, 17% diabetic, mean body mass index 26.9, range 20-56) with 30 OTA 31A3 fractures treated between 2003 and 2007 were included. TREATMENT: Operative fixation using 4.5-mm locking compression plate (LCP) proximal femur plate (Synthes, Paoli, PA). MAIN OUTCOME MEASUREMENTS: Mechanical failure was defined as loss of alignment of at least 10° or shortening of at least 2 cm. Secondary outcomes included patient and fixation construct variables as possible predictors for mechanical failure. RESULTS: At 20 months of follow-up, 11 failures (37%) occurred. Mean time to failure was 18 weeks (range 2-84). Cumulative failure rates were 10%, 20%, 27%, and 33% at 1, 2, 6, and 12 months, respectively. The most frequent failure mode was varus collapse with screw cut out (5 cases). There was no statistically significant difference between groups with regards to age, body mass index, diabetes, or smoking habit. The presence of a "kickstand screw" and medial cortical reduction were not significantly different in cases with and without failure. Proximal screw number and type were similar in both groups. CONCLUSIONS: A high rate of mechanical failure can be expected with proximal locking plate fixation of unstable proximal femur fractures. The use of a "kickstand" screw could not be established to reduce the risk for mechanical failure. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.