Intramuscular Pulsed Radiofrequency Upregulates BNDF-TrKB Expression in the Spinal Cord in Rats as an Alternative Treatment for Complicated Pain.

Two cases of complicated pain exist: posterior screw fixation and myofascial pain. Intramuscular pulsed radiofrequency (PRF) may be an alternative treatment for such patients. This is a two-stage animal study. In the first stage, two muscle groups and two nerve groups were subdivided into a high-temperature group with PRF at 58 °C and a regular temperature with PRF at 42 °C in rats. In the second stage, two nerve injury groups were subdivided into nerve injury with PRF 42 °C on the sciatic nerve and muscle. Blood and spinal cord samples were collected. In the first stage, the immunohistochemical analysis showed that PRF upregulated brain-derived neurotrophic factor (BDNF) in the spinal cord in both groups of rats. In the second stage, the immunohistochemical analysis showed significant BDNF and tropomyosin receptor kinase B (TrkB) expression within the spinal cord after PRF in muscles and nerves after nerve injury. The blood biomarkers showed a significant increase in BDNF levels. PRF in the muscle in rats could upregulate BDNF-TrkB in the spinal cord, similar to PRF on the sciatica nerve for pain relief in rats. PRF could be considered clinically for patients with complicated pain and this study also demonstrated the role of BDNF in pain modulation. The optimal temperature for PRF was 42 °C.

First 100 total hip arthroplasties performed by a young surgeon using the direct anterior approach: learning curve and complications.

INTRODUCTION: Most of the reported discussions about the learning curve for the direct anterior approach (DAA) in total hip arthroplasty (THA) have been by experienced surgeons. The study's aim was to describe the learning curve, short-term outcomes, complications, and adaptations to the DAA used in the first 100 THA cases experienced by a young surgeon who had received DAA training for trauma surgeries. MATERIALS AND METHODS: This retrospective study summarizes the first 100 consecutive cases experienced by a young surgeon who performed the unilateral DAA for THA between 2019 and 2021. Cumulative sum (CUSUM) analysis was performed to evaluate the learning curve on the basis of operative time and overall complications. The demographics data, short-term outcomes, and complications of the first 50 and second 50 cases were compared. RESULTS: The CUSUM curve declined after 49 and 55 cases, measured by operative time and overall complications, respectively. The median operative time (104 vs. 80 min) and intraoperative fluoroscopic time (38 vs. 12 s) increased significantly in the first 50 cases compared with the times in the second 50 cases. Complications tended to occur in the first 50 cases (12% vs. 6%), and the overall rate was 9%. Major complications all occurred in the first 50 cases, with a rate of 4%. Only one case, which involved a complicated periprosthetic fracture around the stem that extended to the tip, required the intervention of a senior surgeon. CONCLUSIONS: Even after receiving training on the DAA for trauma surgeries, the young surgeon experienced a steep learning curve and more complications in the first 50 cases. The DAA for THA is a technically demanding procedure and may require guidance from an experienced surgeon to manage unexpected complications.

Cyclic Stability of Locking Plate Augmented with Intramedullary Polymethyl Methacrylate (PMMA) Strut Fixation for Osteoporotic Humeral Fractures: A Biomechanical Study.

The locking plate may provide improved fixation in osteoporotic bone; however, it has been reported to fail due to varus collapse or screw perforation of the articular surface, especially in osteoporotic bone with medial cortex comminution. Using bone graft as an intramedullary strut together with plate fixation may result in a stronger construct. However, the drawbacks of bone grafts include limited supply, high cost, and infection risk. PMMA (so-called bone cement) has been widely used for implant fixation due to its good mechanical properties, fabricability, and biocompatibility. The risk of donor-site infection and the drawbacks of allografting may be overcome by considering PMMA struts as alternatives to fibular grafts for humeral intramedullary grafting surgeries. However, the potential effects of intramedullary PMMA strut on the dynamic behaviour of osteoporotic humerus fractures remain unclear. This study aimed to investigate the influence of an intramedullary PMMA strut on the stability of unstable proximal humeral fractures in an osteoporotic synthetic model. Two fixation techniques, a locking plate alone (non-strut group) and the same fixation augmented with an intramedullary PMMA strut (with-strut group), were cyclically tested in 20 artificial humeral models. Axially cyclic testing was performed to 450 N for 10,000 cycles, intercyclic motion, cumulated fragment migration, and residual deformation of the constructs were determined at periodic cyclic intervals, and the groups were compared. Results showed that adding an intramedullary PMMA strut could decrease 1.6 times intercyclic motion, 2 times cumulated fracture gap migration, and 1.8 times residual deformation from non-strut fixation. During cycling, neither screw pull-out, cut-through, nor implant failure was observed in the strut-augmented group. We concluded that the plate-strut mechanism could enhance the cyclic stability of the fixation and minimize the residual displacement of the fragment in treating osteoporotic proximal humeral unstable fractures. The PMMA strut has the potential to substitute donor bone and serve as an intramedullary support when used in combination with locking plate fixation. The intramedullary support with bone cement can be considered a solution in the treatment of osteoporotic proximal humeral fractures, especially when there is medial comminution.

A comprehensive painkillers screening by assessing zebrafish behaviors after caudal fin amputation.

Recently, the usage of zebrafish for pain studies has increased in the past years, especially due to its robust pain-stimulated behaviors. Fin amputation has been demonstrated to induce a noxious response in zebrafish. However, based on the prior study, although lidocaine, the most used painkiller in zebrafish, has been shown to ameliorate amputated zebrafish behaviors, it still causes some prolonged effects. Therefore, alternative painkillers are always needed to improve the treatment quality of fin-amputated zebrafish. Here, the effects of several analgesics in recovering zebrafish behaviors post-fin amputation were evaluated. From the results, five painkillers were found to have potentially beneficial effects on amputated fish behaviors. Overall, these results aligned with their binding energy level to target proteins of COX-1 and COX-2. Later, based on their sub-chronic effects on zebrafish survivability, indomethacin, and diclofenac were further studied. This combination showed a prominent effect in recovering zebrafish behaviors when administered orally or through waterborne exposure, even with lower concentrations. Next, based on the ELISA in zebrafish brain tissue, although some changes were found in the treated group, no statistical differences were observed in most of the tested biomarkers. However, since heatmap clustering showed a similar pattern between biochemical and behavior endpoints, the minor changes in each biomarker may be sufficient in changing the fish behaviors.

Dumontier group 2 radiocarpal fracture-dislocation: The results of open reduction and fixation without volar ligament repair.

INTRODUCTION: The radiocarpal fracture-dislocations are a spectrum of severe injury involving both the bony and ligamentous structures that stabilise the wrist joint. The aim of this study was to analyse the outcome of open reduction and fixation without volar ligament repair for Dumontier group 2 radiocarpal fracture-dislocation and to evaluate the incidence and clinical relevance of ulnar translation and advanced osteoarthritis. PATIENTS AND METHODS: We retrospectively reviewed 22 patients with Dumontier group 2 radiocarpal fracture-dislocation treated in our institute. Clinical and radiological outcomes were recorded. Postoperative visual analogue scale (VAS) score for pain, Disabilities of the Arm, Shoulder and Hand Outcome Measure (DASH), and Mayo modified wrist scores (MMWS) were collected. Furthermore, extension‒flexion and supination‒pronation arcs were collected by reviewing chart, either. We divided the patients into two groups according to the presence or absence of advanced osteoarthritis, and presented the differences in the pain, disability, wrist performance, and range of motion between the two groups. We performed the same comparison between the patients with and those without the ulnar translation of the carpus. RESULTS: There were sixteen men and six women with a median age of 23 years (range, 20‒48 years). The median follow-up period was 33 months (range, 12-149 months). The median VAS, DASH and MMWS were 0 (range 0-2), 9.1 (range, 0-65.9) and 80 (range, 45-90), respectively. The median flexion‒extension and pronation‒supination arcs were 142.5° (range, 20°â€’170°) and 147.5° (range, 70°â€’175°), respectively. Ulnar translation was recognised in four patients and the development of advanced osteoarthritis was noted in 13 patients during the follow-up period. However, neither was highly correlated with functional outcomes. CONCLUSION: The current study postulated that ulnar translation might occur following treatment for Dumontier group 2 lesions, whereas injury was predominantly caused by rotational force. Therefore, radiocarpal instability should be recognized during the operation. However, the clinical relevance of ulnar translation and wrist osteoarthritis needs to be assessed in further comparison studies.

Does an Internal Joint Stabilizer and Standardized Protocol Prevent Recurrent Instability in Complex Persistent Elbow Instability?

BACKGROUND: The treatment of complex persistent elbow instability after trauma is challenging. Previous studies on treatments have reported varied surgical techniques, which makes it difficult to establish a therapeutic algorithm. Furthermore, the surgical procedures may not sufficiently restore elbow stability, even with an additional device, and a noted high rate of arthritis progression.While a recently developed internal joint stabilizer effectively treats elbow instability, its clinical application for complex persistent elbow instability is limited and the standardized protocol is not well described. Additionally, we want to know whether the arthritis progression will cause a negative impact on the functional outcomes of complex persistent elbow instability. QUESTIONS/PURPOSES: (1) Does treatment of complex persistent elbow instability with a hinged internal joint stabilizer and a standardized protocol prevent recurrent instability and other complications? (2) What are the pre- to postoperative improvements in pain, disability, elbow performance, and ROM? (3) Is the development of post-traumatic arthritis associated with worse pain, disability, elbow performance, and ROM? METHODS: Between September 2014 and October 2019, we treated 22 patients for persistent dislocation or subluxation after initial treatment of traumatic elbow fracture-dislocations. Of those, we considered patients who were at least 20 years of age, with an interval of 6 weeks or more between the injury (initial treatment) and the index reconstructive procedure, which had been performed at our institute, as potentially eligible. During that time, we used an internal joint stabilizer with a standardized protocol for posttraumatic complex persistent elbow instability. We performed total elbow replacements in patients older than 50 years who had advanced elbow arthritis. Based on that, 82% (18 of 22) of patients were eligible; 14% (3 of 22) were excluded because total elbow replacements was undertaken, and another 5% (1 of 22) were lost before the minimum study follow-up of 1 year (median 24 months [range 12 to 63]), leaving 64% (14 of 22) for analysis in this retrospective study. We treated 14 patients (14 elbows) with posttraumatic complex persistent elbow instability with an internal joint stabilizer and a standardized protocol that comprised debridement arthroplasty with ulnar neurolysis, restoration of bony and ligamentous (reattachment) structures, application of an internal joint stabilizer, and early rehabilitation. There were eight men and six women in this study, with a median (range) age of 44 years (21 to 68). The initial elbow fracture-dislocation injury pattern was a terrible triad injury in seven patients, a posterolateral rotatory injury in four patients, and a posterior Monteggia fracture in three patients. Preoperative and follow-up radiographs were reviewed for evidence of recurrent instability and arthritis. Complications such as wound infection, seroma, neurovascular injury, and hardware complications were ascertained through chart review. Preoperative and postoperative VAS score for pain, DASH, and Mayo Elbow Performance Scores (MEPS) were collected and compared. Furthermore, extension-flexion and supination-pronation arcs were collected by chart review. We divided the patients into two groups according to whether or not they developed posttraumatic arthritis. We then presented the differences between pain, disability, elbow performance, and ROM. The hinged internal joint stabilizer was removed using another open procedure under general anesthesia 6 to 8 weeks after surgery. RESULTS: There were no recurrent instability during and after device removal. Seven patients developed complications, including wound infection, seroma, neurovascular injury, hardware complications, and heterotopic ossification. Two patients had complications related to internal joint stabilizers and three had complications linked to radial head prostheses. Median (range) preoperative to postoperative changes included decreased pain (VAS 5 [2 to 9] to 0 [0 to 3], difference of medians -5; p < 0.001), decreased disability (DASH 41 [16 to 66] to 7 [0 to 46], difference of medians -34; p < 0.001), improved function (MEPS 60 [25 to 70] to 95 [65 to 100], difference of medians 35; p < 0.001), improved extension-flexion arc (40° [10° to 70°] to 113° [75° to 140°], difference of medians 73°; p < 0.001), and supination-pronation arc (78° [30° to 165°] to 148° [70° to 175°], difference of medians 70°; p < 0.001). Between patients with and without development of post-traumatic arthritis, there were no differences in postoperative pain (VAS 0 [0 to 3] to 0 [0 to 1], difference of medians 0; p = 0.17), disability (DASH 7 [0 to 46] to 7 [0 to 18], difference of medians 0; p = 0.40), function (MEPS 80 [65 to 100] to 95 [75 to 100], difference of medians 15; p = 0.79), extension-flexion arc (105° [75° to 140°] to 115° [80° to 125°], difference of medians 10°; p = 0.40), and supination-pronation arc (155° [125° to 175°] to 135° [70° to 160°], difference of medians -20°; p < 0.18). CONCLUSION: In this small, retrospective study, we found that an internal joint stabilizer with a standardized treatment protocol could maintain concentric reduction while allowing early functional motion, and that it could improve clinical outcomes for patients with complex persistent elbow instability. However, patients must be counseled that the complications related to the radial head prostheses may occur, and that the benefits of early motion must compensate for an additional removal procedure and the risk of seroma formation. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Biomechanical Effect of Hybrid Dynamic Stabilization Implant on the Segmental Motion and Intradiscal Pressure in Human Lumbar Spine.

The hybrid dynamic stabilization system, Dynesys-Transition-Optima, represents a novel pedicle-based construct for the treatment of lumbar degenerative disease. The theoretical advantage of this system is to stabilize the treated segment and preserve the range of motion within the adjacent segment while potentially decreasing the risk of adjacent segment disease following lumbar arthrodesis. Satisfactory short-term outcomes were previously demonstrated in the Dynesys-Transition-Optima system. However, long-term follow-up reported accelerated degeneration of adjacent segments and segmental instability above the fusion level. This study investigated the biomechanical effects of the Dynesys-Transition-Optima system on segment motion and intradiscal pressure at adjacent and implanted levels. Segmental range of motion and intradiscal pressure were evaluated under the conditions of the intact spine, with a static fixator at L4-5, and implanted with DTO at L3-4 (Dynesys fixator) and L4-5 (static fixator) by applying the loading conditions of flexion/extension (±7.5 Nm) and lateral bending (±7.5 Nm), with/without a follower preload of 500 N. Our results showed that the hybrid Dynesys-Transition-Optima system can significantly reduce the ROM at the fusion level (L4-L5), whereas the range of motion at the adjacent level (L3-4) significantly increased. The increase in physiological loading could be an important factor in the increment of IDP at the intervertebral discs at the lumbar spine. The Dynesys-Transition-Optima system can preserve the mobility of the stabilized segments with a lesser range of motion on the transition segment; it may help to prevent the occurrence of adjacent segment degeneration. However, the current study cannot cover all the issues of adjacent segmental diseases. Future investigations of large-scale and long-term follow-ups are needed.

A cost and efficacy analysis of performing arthroscopic excision of wrist ganglions under wide-awake anaesthesia versus general anaesthesia.

BACKGROUND: Arthroscopic excision has currently become popular for the treatment of wrist ganglions. The objective of this study was to evaluate the clinical outcomes and cost effectiveness of arthroscopic wrist ganglion excisions under Wide-Awake Local Anaesthesia No Tourniquet versus general anaesthesia. METHODS: We retrospectively reviewed patients who underwent arthroscopic ganglionectomy from April 2009 to October 2016 at our institute. They were separated into two groups according to anaesthesia techniques: general anaesthesia and Wide-Awake Local Anaesthesia No Tourniquet. We compared the clinical outcomes and cost-effectiveness of the two groups. RESULTS: Seventy-four patients were included. Both groups were matched with regard to the demographics and preoperative clinical assessments. We found no significant differences between groups in postoperative visual analog scale, modified Mayo wrist score, Disabilities of Arm, Shoulder and Hand score, recurrence, residual pain, or complications. Recurrence was found in five of 74 patients, one (4.3%) in the Wide-Awake Local Anaesthesia No Tourniquet group and four (7.8%) in the general anaesthesia group. One extensor tendon injury and four extensor tenosynovitis cases occurred in the general anaesthesia group. Regarding cost effectiveness, the mean operating time in the Wide-Awake Local Anaesthesia No Tourniquet and general anaesthesia groups were 88.7 ± 24.51 and 121.5 ± 25.75 min, respectively (p < 0.001). The average total costs of the Wide-Awake Local Anaesthesia No Tourniquet and general anaesthesia groups were €487.4 ± 89.15 and €878.7 ± 182.13, respectively (p < 0.001). CONCLUSIONS: For arthroscopic wrist ganglion resections, both anaesthesia techniques were effective and safe regarding recurrence rates, complications, and residual pain. The most important finding of this study was that arthroscopic ganglionectomy under Wide-Awake Local Anaesthesia No Tourniquet was superior to that under general anaesthesia for cost-effectiveness. LEVEL OF EVIDENCE: Level III, Retrospective comparative study.

Assessment of thermal necrosis risk regions for different bone qualities as a function of drilling parameters.

BACKGROUND AND OBJECTIVE: During bone drilling, the heat generated by friction depends directly on bone quality and surgical parameters. Excessive bone temperatures may cause thermal necrosis around the pilot hole, weaken the purchase of inserted screws, and in turn reduce the stability of screw fixation. A few studies have addressed the key parameters of drilling, such as the rotation speed of the drill-bit, feed force (axial force), feed rate, tool type, and tip geometry of drill-bits. Nevertheless, in the literature, information on the relationship between bone quality and thermally affected regions is still lacking. This study employed a three-dimensional dynamic elastoplastic finite element model to evaluate the influence of surgical parameters on the bone temperature elevation and assess the risk region of thermal necrosis for different bone qualities as a function of drilling parameters. METHODS: To ascertain the heat generation rate and the high-risk region of thermal necrosis, the effects of bone quality, feed rate, feed force, and drill-bit diameter on the bone temperature elevation were explained using a three-dimensional dynamic elastoplastic finite element model, which was validated through experimental measurements. RESULTS: The bone temperature was affected by the drilling parameters; the maximum temperature was attained at the junction of cancellous and cortical bones. The bone temperature increased with cortical bone thickness, bone density, and drill-bit diameter, and it decreased with the drilling speed and feed force. CONCLUSIONS: The present model could assess the risk region of thermal necrosis by accurately analyzing the bone temperature elevation for various bone qualities, feed forces, and feed rates. The bone temperature increased with the bone mineral density and cortical bone thickness. The highest bone temperature and maximum necrosis region were found near the junction of cortical and cancellous bones. Increasing the drilling speed or feed force can minimize the bone temperature elevation and the risk range of thermal necrosis.

Endovascular retrieval of a migrating pedicle screw within the inferior vena cava after instrumented spinal surgery: case report.

During L3-5 instrumented spinal surgery for degenerative spondylolisthesis in a 75-year-old woman, the right L-3 pedicle screw was accidentally pushed into the retroperitoneum and then migrated to the inferior vena cava (IVC). The patient was transferred to the surgical intensive care unit, and after careful discussion with cardiology specialists, a minimally invasive endovascular technique was used to remove the migrating pedicle screw within the IVC and thus salvage this critical case. Pedicle screw instrumentation is an effective procedure, but not risk free. Every detail should be scrutinized during surgery, even instrument construction. A minimally invasive endovascular technique should be considered in this patient population.

Masquelet technique with external locking plate for recalcitrant distal tibial nonunion.

OBJECTIVE: In the present retrospective study, we aimed to analyze the results of treatment for recalcitrant distal tibial nonunion using Masquelet technique with locking plate as a definitive external fixator. MATERIALS: We included 15 consecutive cases of distal tibial nonunion treated at our hospital between January 2012 and December 2015. The reconstructive procedure comprised debridement of the nonunion site, deformity correction, stabilization with an external locked plate, defect filling with cement spacer for inducing membrane formation, and bone reconstruction using a cancellous bone autograft (Masquelet technique). All patients were followed-up for at least one year. RESULTS: Fracture union occurred in all cases after a median of 6.5 months (range, 5-12 months). Mean ankle motion ranged from 12.3 (range, 5-20) degrees of dorsiflexion to 35 (range, 5-55) degrees of plantar flexion. At the final follow-up, the median Iowa ankle score was 83 (range, 68-91). Eight patients had excellent scores, six had good scores, and one had fail score. CONCLUSION: Although the current study involved only a small number of patients and the intervention comprised two stages, we consider that the used protocol is a simple and valuable alternative for the treatment of recalcitrant distal tibial nonunion.

Kirschner Wire and Bone Cement is a Viable Alternative to Reconstruction of Large Iliac Bone Defects After Strut Bone Graft Harvesting.

STUDY DESIGN: A retrospective study. OBJECTIVE: To assess the safety and efficacy of iliac crest defect reconstruction using Kirschner wire (K-wire)/polymethylmethacrylate (PMMA) versus traditional autologous rib graft reconstruction. SUMMARY OF BACKGROUND DATA: The iliac crest has been the preferred donor site for strut bone graft for various spinal fusion surgeries. METHODS: Seventy-three patients (44 males and 29 females; average age: 57.2 y) were divided into 2 groups: the rib group (35 patients) and the K-wire/PMMA group (38 patients). All operations involved anterior spinal interbody fusion. Patients were followed-up, on average, for 34.2 months using plain radiographs and both pain and cosmesis visual analog scales (VAS) to assess the clinical results after surgery. RESULTS: Almost all patients had pain VAS scores of ≤1 and grade 1 cosmesis VAS scores with no significant difference between the 2 groups in terms of either pain or cosmesis (P=1.00 and 0.505, respectively). In addition, few complications were noted in both groups. Radiographic complications in the rib group and the K-wire group numbered 4 (11%) and 2 (5%), respectively; however, did not significantly differ between the 2 groups (P=0.418). One case required intraoperative revision of the length of the K-wire and 1 case needed reoperation for iliac ring fracture and K-wire migration. An additional case required revision due to a bad fall. CONCLUSIONS: K-wire and bone cement reconstruction is an effective and safe alternative method for large iliac bone defect repair when autologous rib graft is not available.

Analysis of Patients with Myelopathy due to Benign Intradural Spinal Tumors with Concomitant Lumbar Degenerative Diseases Misdiagnosed and Erroneously Treated with Lumbar Surgery.

OBJECTIVE: When a cervical or thoracic benign intradural spinal tumor (BIST) coexists with lumbar degenerative diseases (LDD), diagnosis can be difficult. Symptoms of BIST-myelopathy can be mistaken as being related to LDD. Worse, an unnecessary lumbar surgery could be performed. This study was conducted to analyze cases in which an erroneous lumbar surgery was undertaken in the wake of failure to identify BIST-associated myelopathy. METHODS: Cases were found in a hospital database. Patients who underwent surgery for LDD first and then another surgery for BIST removal within a short interval were studied. Issues investigated included why the BISTs were missed, how they were found later, and how the patients reacted to the unnecessary lumbar procedures. RESULTS: Over 10 years, 167 patients received both surgeries for LDD and a cervical or thoracic BIST. In 7 patients, lumbar surgery preceded tumor removal by a short interval. Mistakes shared by the physicians included failure to detect myelopathy and a BIST, and a hasty decision for lumbar surgery, which soon turned out to be futile. Although the BISTs were subsequently found and removed, 5 patients believed that the lumbar surgery was unnecessary, with 4 patients expressing regrets and 1 patient threatening to take legal action against the initial surgeon. CONCLUSIONS: Concomitant symptomatic LDD and BIST-associated myelopathy pose a diagnostic challenge. Spine specialists should refrain from reflexively linking leg symptoms and impaired ability to walk to LDD. Comprehensive patient evaluation is fundamental to avoid misdiagnosis and wrong lumbar surgery.

Evaluation of the parameters affecting bone temperature during drilling using a three-dimensional dynamic elastoplastic finite element model.

A three-dimensional dynamic elastoplastic finite element model was constructed and experimentally validated and was used to investigate the parameters which influence bone temperature during drilling, including the drill speed, feeding force, drill bit diameter, and bone density. Results showed the proposed three-dimensional dynamic elastoplastic finite element model can effectively simulate the temperature elevation during bone drilling. The bone temperature rise decreased with an increase in feeding force and drill speed, however, increased with the diameter of drill bit or bone density. The temperature distribution is significantly affected by the drilling duration; a lower drilling speed reduced the exposure duration, decreases the region of the thermally affected zone. The constructed model could be applied for analyzing the influence parameters during bone drilling to reduce the risk of thermal necrosis. It may provide important information for the design of drill bits and surgical drilling powers.

Intramedullary cortical bone strut improves the cyclic stability of osteoporotic proximal humeral fractures.

BACKGROUND: Proximal humeral fractures treated with locking plate can fail due to varus collapse, especially in osteoporotic bone with medial cortex comminution. The use of an intramedullary strut together with locking plate fixation may strengthen fixation and provide additional medial support to prevent the varus malalignment. This study biomechanically investigates the influence of an intramedullary cortical bone strut on the cyclic stability of proximal humeral fractures stabilized by locking plate fixation in a cadaver model. METHODS: Ten cadaveric humeri were divided into two groups statistically matched for bone density. Each specimen was osteotomized with 10 mm gap at the surgical neck. The non-augmented group stabilized with locking plate alone; in the augmented group, a locking plate was used combined with an intramedullary cortical bone strut. The strut was retrograded into the subchondral bone, and three humeral head screws were inserted into the strut to form a plate-screw-strut mechanism. The cyclic axial load was performed to 450 N for 6000 cycles and then loaded to failure. Construct stiffness, cyclic loading behavior and failure strength were analyzed to identify differences between groups. RESULTS: The augmented constructs were significantly stiffer than the non-augmented constructs during cycling. On average, the maximum displacements at 6000 cycles for non-augmented and augmented groups were 3.10 ± 0.75 mm and 1.7 ± 0.65 mm (p = 0.01), respectively. The mean peak-to-peak (inter cycle) displacement at 6000 cycles was about 2 times lower for the augmented group (1.36 ± 0.68 mm vs. 2.86 ± 0.51 mm). All specimens showed varus collapse combined with loss of screw fixation of the humeral head. The failure load of the augmented group was increased by 2.0 (SD = 0.41) times compared with the non-augmented group (p < 0.001). CONCLUSIONS: The stability and strength of the locking plate augmented with an intramedullary strut were significantly increased. For bone with poor quality, the subsidence of the locked screws led larger displacement, decreased the stability of the constructs, however, the plate-screw-strut mechanism provided more rigidity to stabilize the fixation. This study emphasized the importance of intramedullary support for the proximal humeral fractures fixed with a locked plate under cyclic loading, especially in bone with poor quality. This work is based on the results of cadaver model, further in vivo analysis is necessary to determine if the clinical results can be extrapolated from this data.

Three-stage treatment protocol for recalcitrant distal femoral nonunion.

INTRODUCTION: In this study, we proposed a three-stage treatment protocol for recalcitrant distal femoral nonunion and aimed to analyze the clinical results. MATERIALS AND METHODS: We retrospective reviewed 12 consecutive patients with recalcitrant distal femoral nonunion undergoing our three-stage treatment protocol from January 2010 to December 2014 in our institute. The three-stage treatment protocol comprised debridement of the nonunion site, lengthening to eliminate leg length discrepancy, deformity correction, stabilization with a locked plate, filling of the defect with cement spacer for inducing membrane formation, and bone reconstruction using a cancellous bone autograft (Masquelet technique) or free vascularized fibular bone graft. The bone union time, wound complication, lower limbs alignment, amount of lengthening, knee range of motion, and functional outcomes were evaluated. RESULTS: Osseous union with angular deformity <5° and leg length discrepancy <1 cm were achieved in all the patients. The average amount of lengthening was 5.88 cm (range 3.5-12 cm). Excellent or good outcomes were obtained in 9 patients. CONCLUSIONS: Although the current study involved only a small number of patients and the intervention comprised three stages, we believe that such a protocol may be a valuable alternative for the treatment of recalcitrant distal femoral nonunion.

Bilateral Portal Percutaneous Endoscopic Debridement and Lavage for Lumbar Pyogenic Spondylitis.

Common management approaches for spinal infections include conservative administration of antibiotics and aggressive surgical debridement. Minimally invasive endoscopic treatment has been reported and is gaining widespread attention because of its simplicity and effectiveness. This study retrospectively evaluated the clinical outcomes of bilateral portal percutaneous endoscopic debridement and lavage with dilute povidone-iodine solution in the treatment of patients with lumbar pyogenic spondylitis. From January 2007 to December 2011, a total of 22 patients diagnosed with single-level lumbar pyogenic spondylitis underwent bilateral portal percutaneous endoscopic debridement and lavage with dilute povidone-iodine solution at the authors' institution. Clinical outcomes were assessed by careful physical examination, visual analog scale pain score, modified MacNab criteria functional score, regular serologic testing, and imaging studies to determine whether percutaneous endoscopic debridement and lavage treatment was successful or if surgical intervention was required. Causative bacteria were identified in 19 (86.4%) of 22 biopsy specimens. Eighteen patients had satisfactory relief of back pain and uneventful recovery after this treatment. The success rate was 81.8% (18 of 22). Both visual analog scale and modified MacNab criteria scores improved significantly in successfully treated patients. No major surgical complications were noted, except for 3 patients who had residual or subsequent paresthesia in the affected lumbar segment. Percutaneous endoscopic debridement and lavage is a minimally invasive procedure that can yield a higher bacterial diagnosis, relieve back pain, and help to eradicate lumbar pyogenic spondylitis. It is an effective alternative treatment for patients with spinal infection before extensive open surgery.