A bioactive nano-calcium phosphate paste for in-situ transfection of BMP-7 and VEGF-A in a rabbit critical-size bone defect: results of an in vivo study.

The aim of this study was to prepare an injectable DNA-loaded nano-calcium phosphate paste that is suitable as bioactive bone substitution material. For this we used the well-known potential of calcium phosphate in bone contact and supplemented it with DNA for the in-situ transfection of BMP-7 and VEGF-A in a critical-size bone defect. 24 New Zealand white rabbits were randomly divided into two groups: One group with BMP-7- and VEGF-A-encoding DNA on calcium phosphate nanoparticles and a control group with calcium phosphate nanoparticles only. The bone defect was created at the proximal medial tibia and filled with the DNA-loaded calcium phosphate paste. As control, a bone defect was filled with the calcium phosphate paste without DNA. The proximal tibia was investigated 2, 4 and 12 weeks after the operation. A histomorphological analysis of the dynamic bone parameters was carried out with the Osteomeasure system. The animals treated with the DNA-loaded calcium phosphate showed a statistically significantly increased bone volume per total volume after 4 weeks in comparison to the control group. Additionally, a statistically significant increase of the trabecular number and the number of osteoblasts per tissue area were observed. These results were confirmed by radiological analysis. The DNA-loaded bone paste led to a significantly faster healing of the critical-size bone defect in the rabbit model after 4 weeks. After 12 weeks, all defects had equally healed in both groups. No difference in the quality of the new bone was found. The injectable DNA-loaded calcium phosphate paste led to a faster and more sustained bone healing and induced an accelerated bone formation after 4 weeks. The material was well integrated into the bone defect and new bone was formed on its surface. The calcium phosphate paste without DNA led to a regular healing of the critical-size bone defect, but the healing was slower than the DNA-loaded paste. Thus, the in-situ transfection with BMP-7 and VEGF-A significantly improved the potential of calcium phosphate as pasty bone substitution material.

Bone morphogenetic protein-2 for the treatment of congenital pseudarthrosis of the tibia or persistent tibial nonunion in children and adolescents: A retrospective study with a minimum 2-year follow-up.

There is a lack of studies reporting on rhBMP-2 application in pediatric orthopaedics, although few reports demonstrated promising results of the use of rhBMP-2 in children, especially for spine fusion and for the treatment of congenital pseudarthrosis of the tibia. The objectives of this study were (1) to examine clinical and radiographic healing after rhBMP-2 application for the treatment of congenital pseudarthrosis of the tibia (CPT) or persistent tibial nonunion in children and adolescents, and (2) to investigate the safety of rhBMP-2 use in these cases. Therefore we reviewed the medical records of ten patients with a mean age of 8.6 years (2.3-21) with CPT (n = 7) or persistent tibial nonunion for at least six months (n = 3) who had been treated with rhBMP-2. Nine of ten patients had union at final follow-up, after a mean of 72.9 months (25-127). In the CPT group, primary healing of the pseudarthrosis occurred in six of seven patients at a mean of 5.2 months (3-12). Repeat rhBMP-2 application was performed in three patients; two patients had one additional application each, and one patient had three additional applications. Complications that may be attributed to the use of rhBMP-2 were seen in two of fifteen applications, including a compartmemt syndrome and a hematoma. In this retrospective case series rhBMP-2 has been used successfully to treat CPT or persistent tibial nonunion in pediatric patients. However, prospective randomized controlled trials are warranted to investigate the long-term efficacy and safety of rhBMP-2 use in these cases.

Acromioclavicular joint dislocations: coracoclavicular reconstruction with and without additional direct acromioclavicular repair.

PURPOSE: To evaluate different stabilisation techniques for acromioclavicular (AC) joint separations, including direct AC repair, and to compare the properties of the stabilised and native joints. METHODS: An established in vitro testing model for the AC joint was used to analyse joint stability after surgical reconstruction [double TightRope (DTR), DTR with AC repair (DTR + AC), single TR with AC repair (TR + AC), and PDS sling with AC repair (PDS + AC)]. Twenty-four human cadaveric shoulders were randomised by age into four testing groups. Joint stiffness was measured by applying an axial load during defined physiological ranges of motion. Similar tests were performed for the native joints, after dissecting the coracoclavicular and AC ligaments, and after surgical reconstruction. Cyclic loading was performed for 1000 cycles with 20-70 N and vertical load to failure determined after cyclic testing. RESULTS: Axial stiffness for all TR groups was significantly higher than for the native joint (DTR 38.94 N/mm, p = 0.005; DTR + AC 37.79 N/mm, p = 0.015; TR + AC 45.61 N/mm, p < 0.001 vs. native 26.05 N/mm). The axial stiffness of the PDS + AC group was similar to that of the native joint group (21.4 N/mm, n.s.). AC repair did not significantly influence rotational stiffness. Load to failure was similar and >600 N in all groups (n.s.). CONCLUSION: Reconstruction of AC dislocations with one or two TRs leads to stable results with a higher stiffness than the native joints. For the PDS + AC group, axial stiffness was similar to the native situation, although there might be a risk of elongation. Direct AC repair showed no significantly increased stability in comparison with reconstructions without direct AC repair. Thus, a direct AC repair seems to be dispensable in clinical practice, while TRs or PDS cerclages appear to provide sufficiently stable results.

Evaluation of complications associated with off-label use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in pediatric orthopaedics.

The off-label use of recombinant human bone morphogenetic protein-2 to promote bone healing in adults has significantly increased in recent years, while reports of recombinant human bone morphogenetic protein-2 application in children and adolescents are very rare. The aim of this study was to evaluate the safety of single and repetitive recombinant human bone morphogenetic protein-2 use in pediatric orthoapedics. Therefore we reviewed the medical records of 39 patients who had been treated with recombinant human bone morphogenetic protein-2 at our institution. Their mean age was 10.9 years. Recombinant human bone morphogenetic protein-2 was used in 17 patients for spine fusion, in 11 patients for the treatment of congenital pseudarthrosis of the tibia or tibial nonunion, in 5 patients for the management of femoral nonunion, in 5 patients for nonunions at other locations, and in 1 case for tibial shortening. Special attention was paid to identify all adverse events that may be attributed to recombinant human bone morphogenetic protein-2 use, including local inflammatory reactions, allergic reactions, systemic toxicity, excessive wound swelling, hematoma, compartment syndrome, infection, heterotopic ossification, excessive bone growth, carcinogenicity, and the consequences of repeated applications of recombinant human bone morphogenetic protein-2. Follow-up was a mean of 39 months. Forty-six operations with application of rhBMP-2 were performed. Complications that may be due to application of recombinant human bone morphogenetic protein-2 were seen after 18 operations including swelling, increase in temperature, wound secretion, redness and hyperthermia. We consider the three cases of necessary revisions, one due to hematoma, one due to development of a compartment syndrome, and one due to deep infection, to be the only complications related to the use of recombinant human bone morphogenetic protein-2. In conclusion, we found few complications attributable to application of recombinant human bone morphogenetic protein-2 in pediatric patients.

On-table decision-making in intracapsular hip fracture surgery: mid-term results of a pilot study.

INTRODUCTION: At the present time, it is generally recommended to use hip replacement in dislocated fractures to avoid failure after internal fixation. A problem is that previous research has demonstrated that observers have problems in discriminating between dislocated and undislocated fractures. A possible solution to this problem would be to use arthroplasty in the majority of the cases. However, this also means that many fractures with the potential for uneventful healing would be replaced. MATERIALS AND METHODS: In the current investigation, the mid-term outcome was recorded for patients with intracapsular hip fractures who were treated with either internal fixation or arthroplasty. A novel treatment algorithm was employed. After careful exclusion of cases with known risk factors for failure after internal fixation, a technique called on-table decision was used to identify suitable patients for internal fixation. RESULTS: A total of 72 patients with intracapsular hip fractures were studied with a median follow-up time of 12 months (IQR 8-15.25 months). Nineteen (19) patients (26 %) were excluded in the selection process, leaving 53 (74 %) for on-table decision-making. Thirty patients (42 %) were identified as suitable for internal fixation and gave anatomically stable closed reductions. Two of these patients (7 %) exhibited non-unions and one (3 %) avascular necrosis. CONCLUSIONS: The mid-term outcome after internal fixation is promising. The careful selection process may be helpful in identifying fracture patterns for which internal fixation may be considered as a safe and less invasive alternative to hip arthroplasty.

Interposition sleeve as treatment option for interprosthetic fractures of the femur: a biomechanical in vitro assessment.

PURPOSE: The number of patients having hip and knee arthroplasties on the ipsilateral leg is going to rise. In this regard, the prevalence of interprosthetic femoral fractures is going to increase further. The treatment of these fractures is difficult and sometimes it is impossible to perform an osteosynthesis because of worse bone quality. The goal of this study was to investigate the use of an interposition sleeve as an alternative treatment option for interprosthetic fractures with major bone loss. METHODS: Six human cadaveric femurs were instrumented using cemented hip- and knee prosthesis. Interprosthetic fractures were induced during a four-point-bending test and then treated using the interposition sleeve. Afterwards the constructs were tested using the four-point-bending test again. RESULTS: Load-to-failure of the construct before fracturing was significantly higher than after treatment with the interposition sleeve (10681 N vs. 5083 N; p = 0.002). The failure mechanism of the femurs with the interposition sleeve was plastic deformation of the hip or knee prosthesis. The interposition sleeve did not fail in any specimen. CONCLUSION: The interposition sleeve is a valuable treatment option for interprosthetic fractures in situations in which osteosynthesis is impossible or insecure due to major bone defects. However, fracture healing should be preferred whenever possible.

Biomechanical advantage of C1 pedicle screws over C1 lateral mass screws: a cadaveric study.

PURPOSE: The established technique for posterior C1 screw placement is via the lateral mass. Use of C1 monocortical pedicle screws is an emerging technique which utilizes the bone of the posterior arch while avoiding the paravertebral venous plexus and the C2 nerve root. This study compared the relative biomechanical fixation strengths of C1 pedicle screws with C1 lateral mass screws. METHODS: Nine human C1 vertebrae were instrumented with one lateral mass screw and one pedicle screw. The specimens were subjected to sinusoidal, cyclic (0.5 Hz) fatigue loading. Peak compressive and tensile forces started from ±25 N and constantly increased by 0.05 N every cycle. Testing was stopped at 5 mm displacement. Cycles to failure, displacement, and initial and end stiffness were measured. Finally, CT scans were taken and the removal torque measured. RESULTS: The pedicle screw technique consistently and significantly outperformed the lateral mass technique in cycles to failure (1,083 ± 166 vs. 689 ± 240 cycles), initial stiffness (24.6 ± 3.9 vs. 19.9 ± 3.2 N/mm), end stiffness (16.6 ± 2.7 vs. 11.6 ± 3.6 N/mm) and removal torque (0.70 ± 0.78 vs. 0.13 ± 0.09 N m). Only 33 % of pedicle screws were loose after testing compared to 100 % of lateral mass screws. CONCLUSIONS: C1 pedicle screws were able to withstand higher toggle forces than lateral mass screws while maintaining a higher stiffness throughout and after testing. From a biomechanical point of view, the clinical use of pedicle screws in C1 is a promising alternative to lateral mass screws.

What is the frequency of nerve injuries associated with acetabular fractures?

BACKGROUND: Acetabular fractures and surgical interventions used to treat them can result in nerve injuries. To date, only small case studies have tried to explore the frequency of nerve injuries and their association with patient and treatment characteristics. High-quality data on the risk of traumatic and iatrogenic nerve lesions and their epidemiology in relation to different fracture types and surgical approaches are lacking. QUESTIONS/PURPOSES: The purpose of this study was to determine (1) the proportion of patients who develop nerve injuries after acetabular fracture; (2) which fracture type(s) are associated with increased nerve injury risk; and (3) which surgical approach was associated with the highest proportion of patients developing nerve injuries using data from the German Pelvic Trauma Registry. Two secondary aims were (4) to assess hospital volume-nerve-injury relationship; and (5) internal data validity. METHODS: Between March 2001 and June 2012, 2236 patients with acetabular fractures were entered into a prospectively maintained registry from 29 hospitals; of those, 2073 (92.7%) had complete records on the endpoints of interest in this retrospective study and were analyzed. The neurological status in these patients was captured at their admission and at the discharge. A total of 1395 of 2073 (67%) patients underwent surgery, and the proportions of intervention-related and other hospital-acquired nerve injuries were obtained. Overall proportions of patients developing nerve injuries, risk based on fracture type, and risk of surgical approach type were analyzed. RESULTS: The proportion of patients being diagnosed with nerve injuries at hospital admission was 4% (76 of 2073) and at discharge 7% (134 or 2073). Patients with fractures of the "posterior wall" (relative risk [RR], 2.0; 95% confidence interval [CI], 1.4-2.8; p=0.001), "posterior column and posterior wall" (RR, 2.9; CI, 1.6-5.0; p=0.002), and "transverse+posterior wall" fracture (RR, 2.1; CI, 1.3-3.5; p=0.010) were more likely to have nerve injuries at hospital discharge. The proportion of patients with intervention-related nerve injuries and that of patients with other hospital-acquired nerve injuries was 2% (24 of 1395 and 46 of 2073, respectively). They both were associated with the Kocher-Langenbeck approach (RR, 3.0; CI, 1.4-6.2; p=0.006; and RR, 2.4; CI, 1.4-4.3; p=0.004, respectively). CONCLUSIONS: Acetabular fractures with the involvement of posterior wall were most commonly accompanied with nerve injuries. The data suggest also that Kocher-Langenbeck approach to the pelvic ring is associated with a higher risk of perioperative nerve injuries. Trauma surgeons should be aware of common nerve injuries, particularly in posterior wall fractures. The results of the study should help provide patients with more exact information on the risk of perioperative nerve injuries in acetabular fractures. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Accuracy analysis of a novel electromagnetic navigation procedure versus a standard minimally invasive method for arthroscopically assisted acromioclavicular joint reconstructions.

PURPOSE: The aim of this cadaveric study was to evaluate the accuracy, feasibility, and operation time of a novel electromagnetic navigation system (ENS) and procedure for transclavicular-transcoracoid tunnel placement compared with a standard minimally invasive (SMI) reconstruction method for minimally invasive arthroscopically assisted anatomic acromioclavicular joint reconstruction. METHODS: Ten arthroscopically assisted electromagnetic-navigated transclavicular-transcoracoid drilling procedures and 10 SMI procedures were performed on 10 human cadavers using 2 TightRope reconstructions (Arthrex, Naples, FL) for each site. Postoperative computed tomography scans were acquired to determine tunnel placement accuracy. Optimal coracoid tunnel placement was defined according to the anatomic insertions of the trapezoid and conoid ligaments with the oblong button placed in a center-base position at the coracoid undersurface without cortical breach or fracture. Both reconstruction procedures were performed without fluoroscopy. RESULTS: Successful tunnel placement was accomplished in 98.8% using the ENS method and in 83.8% using the SMI procedure (P = .087). The mean overall operation time was 28.5 ± 6.6 minutes for the ENS method and 35.2 ± 3.9 minutes for the SMI method (P = .012). The ENS procedure required no directional readjustments or restarts. Drill misguidance with subsequent cortical breach occurred twice in the SMI group. In both groups no fractures were documented. CONCLUSIONS: In this descriptive laboratory study, both the ENS and the SMI techniques achieved the desired anatomic reconstruction. Compared with the SMI method, the ENS procedure showed higher accuracy, required a shorter operation time, and was associated with no complications. CLINICAL RELEVANCE: Length of surgery, drilling accuracy, and reduction of radiation exposure in acromioclavicular joint reconstruction procedures affect the safety of both patients and surgeons.

Electromagnetic navigation provides high accuracy for transcoracoid-transclavicular drilling.

PURPOSE: A novel radiation-free electromagnetic navigation system (ENS)-based method was developed, and its feasibility and accuracy for transclavicular-transcoracoid drilling procedures were evaluated in an experimental setting. METHODS: Sixteen arthroscopically assisted electromagnetic navigated transcoracoid-transclavicular drilling procedures with subsequent TightRope device implantation were performed on eight human cadavers. Post-operative fluoroscopy and CT-scan analysis were acquired to determine tunnel placement accuracy. Optimal tunnel placement was defined as both the coracoid entry and exit point of the tunnel localized in the centre position of the coracoid base without cortical breach or fracture. RESULTS: Successful tunnel placement was accomplished in all 16 cases. The mean overall operation time was 30.3 ± 5.0 min. Regarding the coracoid exit point, 15 of 16 tunnels (93.8%) were localized in the desired base-centre position. During the navigated drilling procedure, no misguidance of the drill requiring directional readjustments or restarts occurred. No cortical breach, no fractures and no complications occurred. CONCLUSIONS: The electromagnetically navigated transcoracoid-transclavicular drilling procedure used in this study demonstrated high targeting accuracy, required no intraoperative radiographs, was associated with no complications and provided user-friendliness.

Tantalum acetabular augments in one-stage exchange of infected total hip arthroplasty: a case-control study.

During the one-stage exchange procedure for periprosthetic joint infection (PJI) after total hip arthroplasty (THA), acetabular defects challenge reconstructive options. Porous tantalum augments are an established tool for addressing acetabular destruction in aseptic cases, but their utility in septic exchange is unknown. This retrospective case-control study presents the initial results of tantalum augmentation during one-stage exchange for PJI. Primary endpoints were rates of re-infection and short-term complications associated with this technique. Study patients had no higher risk of re-infection with equivalent durability at early follow-up with a re-infection rate in both groups of 4%. In conclusion, tantalum augments are a viable option for addressing acetabular defects in one-stage exchange for septic THA. Further study is necessary to assess long-term durability when compared to traditional techniques for acetabular reconstruction.

Restoration of hip architecture with bipolar hemiarthroplasty in the elderly: does it affect early functional outcome?

INTRODUCTION: Reconstruction of the anatomic architecture correlates with functional outcome in patients receiving elective total hip arthroplasty. In theory similar rules should apply for bipolar hemiarthroplasty in femoral neck fractures. The influence of anatomic restoration after bipolar hemiarthroplasty on short-term clinical and functional outcome is explored in this study. PATIENTS AND METHODS: Patients receiving bipolar hemiarthroplasty for intracapsular femoral neck fractures between 2010 and 2012 were included into a retrospective cohort study. Radiologic and functional outcome parameters were recorded during the acute care phase and geriatric rehabilitation. Postoperative mobilization data were recorded and co-morbidities documented for each case. Outcome parameters were obtained during geriatric rehabilitation: Barthel index, Tinetti score, Timed up and go test, Mini-Mental State Examination. The FO-ratio (ratio of femoral offset to the body weight lever arm), HC-ratio (ratio of the height of the hip center to the pelvic height) and the BWLA ratio (ratio of the body weight lever arm to the pelvic height) were obtained from postoperative radiographs. RESULTS: A total of 193 patients with a median age of 84 (IQR = 78-94, 72% female) were analyzed. The in-hospital mortality rate was 5.7%. There was a high proportion of patients with prior co-morbidities (96% with at least one co-morbidity). During rehabilitation the Barthel index improved significantly (p < 0.001) from 40 to 55. The median Tinetti score on rehabilitation discharge was 15.5 (IQR = 10-19.5). The patients significantly improved in the timed up and go test from a median of 22 to 19 s. A significant difference (p < 0.001) was found comparing the FO ratios of the operated vs. non-operated side. None of the radiographic measures, representing the reconstructed anatomic hip geometry, significantly influenced the clinical and geriatric outcome. CONCLUSIONS: Applying the short-term functional outcome scores used in this study, optimized anatomic restoration in hemiarthroplasty may not be a major influencing factor in a cohort of elder, multi-morbid patients.

Does the cement stiffness affect fatigue fracture strength of vertebrae after cement augmentation in osteoporotic patients?

PURPOSE: Normal progression of osteoporosis or the rigid reinforcement of the fractured vertebral body with polymethyl methacrylate (PMMA) cement is being discussed as a cause for adjacent-level fractures after vertebroplasty. The purpose of this study was to investigate whether augmentation with low stiffness cement can decrease the risk of adjacent-level fractures in low-quality bone. METHODS: Eighteen female osteoporotic lumbar specimens (L1-L5) were harvested and divided into three groups according to bone mineral density: (I) native; (II) PMMA; (III) modified PMMA (lower stiffness). For the PMMA and modified PMMA groups, a compression fracture was first mechanically induced in L3, and then the fracture received vertebroplasty treatment. The cement stiffness reduction of the modified PMMA group was achieved via an addition of 8 mL of serum to the typical PMMA base. All specimens were exposed to cyclic loading (4 Hz) and a stepwise increasing applied peak force. Cement stiffness was tested according to ISO 5833. RESULTS: A 51% decrease in cement stiffness was achieved in the modified PMMA group (954 ± 141 vs. 1,937 ± 478 MPa, p < 0.001). Fatigue fracture force (the force level during cyclic loading at which the deformation experienced a sudden increase; FFF) was significantly affected by bone quality (r (2) = 0.39, p = 0.006) and by the initial fracture force (the force necessary to create the initial fracture in L3 prior to augmentation; r (2) = 0.82, p < 0.001). Using initial fracture force as a covariate, the FFF of the modified PMMA group (1,764 ± 49 N) was significantly higher than in the PMMA group (1,544 ± 55 N; p = 0.03). CONCLUSIONS: A possible method to reduce adjacent-level fractures after vertebroplasty in patients with reduced bone quality could be the use of a lower modulus cement. Therefore, mixing cement with biocompatible fluids could prove useful to tailor cement properties in the operating theater.

The degree of articular depression as a predictor of soft-tissue injuries in tibial plateau fracture.

PURPOSE: Magnetic resonance imaging (MRI) provides sufficient information with regard to specific soft-tissue injuries in the knee, but it is not generally used to evaluate acute tibial plateau fractures. The aim of the present study was to determine whether the amount of tibial plateau fracture depression on multi-detector computed tomography (MDCT) scans correlates with the incidence of associated soft-tissue injuries on MRI. METHODS: A total of 54 consecutive patients with a mean age of 51.2 years (SD = 18.3) were included in this retrospective study. All patients were admitted to the emergency department of a university clinic with acute tibial plateau fracture. The amount of articular depression was assessed from MDCT scans. Magnetic resonance images were evaluated for crucial and collateral ligament injury, meniscal tears, and patellar retinaculum lesions. RESULTS: Logistic regression revealed a significant impact of increasing tibial plateau fracture depression on the incidence of meniscus lateralis tears (P = 0.025) and anterior cruciate ligament lesions (P = 0.018). Analysis of covariance demonstrated a significant correlation between the amount of articular depression and absolute number of soft-tissue injuries (P = 0.001). CONCLUSIONS: Articular depression is a potential predictor of specific meniscal and ligamentous injuries in acute tibial plateau fracture. Magnetic resonance imaging is generally recommended with respect to associated soft-tissue injuries, especially in cases with distinct tibial plateau fracture depression on multi-detector computed tomography scans. LEVEL OF EVIDENCE: Case series, Level IV.

Incidence of bacterial contamination in primary THA and combined hardware removal: analysis of preoperative aspiration and intraoperative biopsies.

Prior fracture surgery in the setting of subsequent arthroplasty may confer an increased risk of infection. The current authors retrospectively reviewed 122 patients from 2006 to 2010. Joint aspirations performed preoperatively in two of 52 patients revealed bacterial growth. Preoperative CRP levels were elevated in 22.8% with a mean value of 10.4 mg/L (range 5.5 to 33.3). Intra-operative cultures were performed in 109 patients, with a single patient sample exhibiting bacterial growth (0.9%). Preoperative aspiration showed a sensitivity of 1.0 and specificity of 0.98 (P<0.039) for bacterial contamination. There was no postoperative periprosthetic infection noted. In conclusion the retrieval of internal fixation devices and total hip arthroplasty can be performed safely as a single stage procedure without significantly increasing the risk of periprosthetic infection.

1-stage primary arthroplasty of mechanically failed internally fixated of hip fractures with deep wound infection: good outcome in 16 cases.

BACKGROUND AND PURPOSE: Mechanically failed internal fixation following hip fracture is often treated by salvage arthroplasty. If deep wound infection is present, a 2-stage procedure is often used. We have used a 1-stage procedure in infected cases, and we now report the outcome. PATIENTS AND METHODS: We reviewed 16 cases of deep wound infection after mechanically failed hip fracture fixation, treated between 1994 and 2010. In all patients, a joint prosthesis was implanted in a 1-stage procedure. RESULTS: After an average follow-up period of 12 (2-18) years, no reinfection was detected. In 4 cases, a hip dislocation occurred and 3 of these needed further surgery. INTERPRETATION: A 1-stage procedure for arthroplasty of an infected, mechanically failed hip fracture fixation is feasible and carries a low risk of infection.

Long-term donor-site morbidity after microsurgical fibular graft: is there a difference between the medial approach and the lateral approach?

PURPOSE: Microvascular fibula harvesting for osseous reconstruction is a valuable aid in maxillofacial surgery. We assessed whether the lateral and the medial harvesting techniques differed with respect to long-term donor-site morbidity. MATERIALS AND METHODS: We conducted a retrospective cohort study of patients who had undergone free fibula harvesting at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany, between 1987 and 2008. The primary predictor variable was the surgical approach. The primary and secondary outcome variables were the American Orthopaedic Foot & Ankle Society score and the result of the Short Form 36 Health Survey on quality of life, respectively. Other variables were age, gender, harvest length, operation time, and specific impairments and surgical complications. Statistical analysis was performed with SPSS, version 14.0 (SPSS, Chicago, IL); P < .05 was considered significant. RESULTS: The 42 patients had a mean age of 55.5 years. The mean follow-up period was 81 months (range, 7-174 months). In the medial group, the mean American Orthopaedic Foot & Ankle Society score was 94.4 points and the total number of impairments was 34, as compared with 85.6 points and 46 impairments, respectively, in the lateral group. This tendency for less morbidity with the medial approach was only found in female patients. The Short Form 36 scores were not statistically different between the 2 surgical approaches. CONCLUSIONS: The medial approach led to less functional impairment of the foot and ankle. Our results support the medial approach as a viable alternative, especially in women, but only in cases when a skin paddle is not necessary.

Treatment of fixed knee flexion deformity by anterior distal femoral stapling.

PURPOSE: The treatment of fixed knee flexion deformity through anterior distal femoral stapling has been investigated in only two studies so far, with promising results. The aim of the present study was to determine whether this technique might improve fixed knee flexion deformity in a series of growing children and adolescents with different conditions. Follow-up examinations were continued after staple removal in terms of a possible impairment of this deformity. METHODS: We reviewed the medical records of all patients with fixed knee flexion deformity who had been treated by anterior distal femoral stapling at our institution. Twenty patients (37 knees) with a mean age of 12.7 years met the inclusion criteria (>12 months of follow-up; no additional procedures to correct fixed knee flexion deformity such as hamstring lengthening or posterior capsulotomy) and were evaluated in this study. RESULTS: The mean fixed knee flexion deformity significantly improved from 21.4° (SD = 11.6) preoperatively to 7.0° (SD = 9.8) after a mean follow-up of 35.3 months. Young patients (<12 years) revealed superior improvement of this deformity, and especially children with distinct fixed knee flexion deformity of 30° or greater had benefit from early treatment. Impairment of flexion deformity was only seen in one patient (2 knees) after staple removal. CONCLUSIONS: Our results demonstrate that anterior distal femoral stapling is an effective method for the treatment of fixed knee flexion deformity in growing children and adolescents. Rare complications, immediate mobilization, and a low recurrence rate after staple removal provide obvious advantages of this minimally invasive procedure. LEVEL OF EVIDENCE: Retrospective therapeutic study, Level IV.

What is the risk of stress risers for interprosthetic fractures of the femur? A biomechanical analysis.

PURPOSE: Due to increasing life expectancy we see a rising number of joint replacements. Along with the proximal prosthesis in the femur, more and more people have a second implant on the distal ipsilateral side. This might be a retrograde nail or a locking plate to treat distal femur fractures or a constrained knee prosthesis in the case of severe arthrosis. All these constructs can lead to fractures between the implants. The goal of this study was to evaluate the risk of stress risers for interprosthetic fractures of the femur. METHODS: Thirty human cadaveric femurs were divided into five groups: (1) femurs with a prosthesis on the proximal side only, (2) hip prosthesis on the proximal end and a distal femur nail, (3) femurs with both a hip prosthesis and a constrained knee prosthesis, (4) femurs with a hip prosthesis on the proximal side and a 4.5-mm distal femur locking plate; the locking plate was 230 mm in length, with ten holes in the shaft, and (5) femurs with a proximal hip prosthesis and a 4.5-mm distal femur locking plate; the locking plate was 342 mm in length, with 16 holes in the shaft. RESULTS: Femurs with a hip prosthesis and knee prosthesis showed significantly higher required fracture force compared to femurs with a hip prosthesis and a distal retrograde nail. Femurs with a distal locking plate of either length showed a higher required fracture force than those with the retrograde nail. CONCLUSIONS: The highest risk for a fracture in the femur with an existing hip prosthesis comes with a retrograde nail. A distal locking plate for the treatment of supracondylar fractures leads to a higher required fracture force. The implantation of a constrained knee prosthesis that is not loosened on the ipsilateral side does not increase the risk for a fracture.

Tibial plateau fracture: does fracture classification influence the choice of surgical approach? A retrospective multicenter analysis.

PURPOSE: The role of classification systems for the choice of surgical approach and the management of tibial plateau fractures remains unclear. The purpose of this study was to investigate the potential of classification systems to choose the appropriate operative approach. Current surgical management strategies were investigated in a large multicenter assessment. METHODS: In this study, we retrospectively analyzed all patients with tibial plateau fractures that have received surgical treatment in one of the five Level I trauma facilities between 2012 and 2015. Fractures were classified in each center by a senior orthopedic surgeon using the AO/OTA and the Luo classification. Demographics, trauma mechanism, as well as the surgical approach were recorded. RESULTS: 538 patients (46.1% male, 53.9% female) were included. The anterolateral approach was used most frequently with 54.8% of all single approaches; 76.2% of all combined approaches used anterolateral as part of the approach. Combined approaches were used in 22.5% of the cases; a combination of the anterolateral and medial (10%), anterolateral, and posteromedial approach (5.8%) were used most frequently. The lowest number was found for the posterolateral (1.3%) and the combined approaches dorsal/anterolateral and medial/dorsal (1.7%, 1.1%). The AO/OTA classification showed a peak for 41.B2 (21.9%) and B3 (35.5%) fractures. Regarding the Luo classification, the dorsal column was involved in 45.7%. In contrast, only 14.7% of the surgical approaches used were able to address the dorsal tibial plateau potentially. CONCLUSION: The use of dorsal approach seems to be of minor importance than expected in daily clinical practice in this multicenter study. It was not possible to specify whether the AO/OTA or the Luo classification can reliably predict the choice of surgical approach. The operative treatment strategy of tibial plateau fractures seems to rather rely on the surgeons' experience, education, and preferences.