Development and Efficacy Testing of a "Hollow Awl" That Leads to Patent Bone Marrow Channels and Greater Mesenchymal Stem Cell Mobilization During Bone Marrow Stimulation Cartilage Repair Surgery.

PURPOSE: To investigate whether microfracture with a cannulated hollow awl can yield more patent marrow channels and allow greater mobilization of the reparable cells to the defect compared to the conventional awl with blunt end in human knee joints. METHODS: Patients who were planned for 1-stage bilateral total knee arthroplasty due to degenerative osteoarthritis with well-preserved lateral femoral condylar cartilage were retrospectively included. A 10-mm × 20-mm, rectangular, full-thickness chondral defect was made on the lateral femoral condyle on each knee joint. The 6-holed microfracture procedure, each at 9 mm depth and 3 mm separation of perforations, was followed using a hollow awl in one knee and using a conventional awl in the other knee, respectively. The bleeding through the microfracture holes was observed and collected using an absorbable gelatin sponge and was analyzed microscopically by colony forming unit-fibroblast assays and automated cell counting method. The representative 3 bony samples of the distal lateral femoral condyles obtained were also scanned with micro-computed tomography (micro-CT) for morphometric analysis (percent bone volume, trabecular separation, and total porosity) of subchondral bone microarchitecture of the microfracture holes. RESULTS: Twenty-two patients were enrolled, and the mean age was 70.8 ± 6.1 (58-83) years. Compared with the conventional awl group, the hollow awl group had a significantly greater amount of bleeding (1.8 ± 0.2 g vs 1.1 ± 0.1 g; P < .001) and a greater number of mesenchymal stem cells in the blood clot (21,474.0 ± 3,911.1 vs 13,329.7 ± 3,311.0; P = .004). The hollow awl group also showed overall more patent marrow channels around the adjacent subchondral bone of the microfracture hole, with greater trabecular separation on micro-CT analysis (P < .001). CONCLUSIONS: Compared to the conventional awl, microfracture with a cannulated hollow awl can yield more patent marrow channels at the adjacent subchondral bone of the microfracture hole and result in greater mobilization of the reparable cells to the defect in human knee joints. LEVEL OF EVIDENCE: Level III, therapeutic case control.

Preoperative evaluation of left common iliac vein in oblique lateral interbody fusion at L5-S1.

PURPOSE: Oblique lateral interbody fusion (OLIF) L5-S1 is essentially to perform an anterior lumbar interbody fusion (ALIF) in the lateral position. Because the surgical procedures are performed "obliquely" over the left common iliac vein (LCIV), ensuring that the vein is protected which is particularly important. We aimed to evaluate the configuration of LCIV and its risk of mobilization during anterior approach at L5-S1 segment. METHODS: This study involved 65 consecutive patients who underwent anterior lumbar fusion (ALIF, n = 39; OLIF, n = 26) at the L5-S1 segment. Three independent examiners evaluated the configuration of the LCIV at the L5-S1 disc on axial magnetic resonance images of the lumbar spine. The LCIV was categorized into three types according to the difficulty of mobilization: type I (no requirement for mobilization; LCIV runs laterally for more than two-thirds of the length of the left side of the L5-S1 disc), type II (easy mobilization; LCIV obstructs the L5-S1 disc space, but the perivascular adipose tissue is present under the LCIV), and type III (potentially difficult mobilization; no perivascular adipose tissue under the LCIV). The patient records were reviewed for vascular complications. RESULTS: There were 21 men and 44 women in this study, with a mean age of 63.4 years (range 19-83 years). Type I LCIV configuration was found in 32 (49.2%) patients, type II in 18 (27.7%), and type III in 15 (23.1%). There were 7 (10.8%) patients with LCIV injury (type I, n = 0; type II, n = 2; type III, n = 5) (P = 0.003). Intraobserver reliability for the LCIV classification ranged from substantial to excellent, and interobserver reliability ranged from moderate to excellent. CONCLUSIONS: Preoperative evaluation for anterior approach to the L5-S1 segment should take account of the LCIV position, as well as the difficulty of its mobilization. The type III LCIV configuration showed a high rate of vascular injury.

Stepwise Percutaneous Leverage Technique to Avoid Posterior Interosseous Nerve Injury in Pediatric Radial Neck Fracture.

OBJECTIVES: To introduce a stepwise percutaneous leverage technique to avoid posterior interosseous nerve (PIN) injury in pediatric patients with radial neck fractures and to evaluate the clinical outcome and the predisposing factors affecting the outcome. DESIGN: Retrospective case series study. SETTING: University level 1 trauma center. PATIENTS: Thirty-four children with a radial neck fracture, who were treated using a stepwise percutaneous leverage technique, were included in the study. INTERVENTION: The radial head fragment was reduced by pulling the first Steinmann pin proximally as a lever. Then, the kinked soft tissue was released by removal of the Steinmann pin with buttressing the radial head by the operator's thumb. The second Steinmann pin was inserted into relaxed soft tissue for fixation of the radial head. MAIN OUTCOME MEASUREMENTS: We used the Métaizeau classification as a radiologic result and Mayo Elbow Performance Score (MEPS) as a clinical outcome. Regression analysis was performed to identify the predisposing factors affecting the outcome. RESULTS: There was no occurrence of PIN palsy. According to the Métaizeau classification, 23 cases were classified as excellent, 9 as good, 1 as fair, and 1 as poor. The average MEPS was 97.6 points. Based on the regression analysis, only the postoperative Métaizeau classification was confirmed as a risk factor of a relatively poor outcome. CONCLUSIONS: The stepwise percutaneous leverage technique can be considered a good option in the treatment of pediatric radial neck fractures, because it ensures excellent results by avoiding injury to soft tissues including the PIN. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The use of interfragmentary positional screw in minimally invasive plate osteosynthesis for simple distal femur fractures in elderly patients: A retrospective, single-centre pilot study.

INTRODUCTION: Minimally invasive plate osteosynthesis (MIPO) using locking plates has been used in distal femur fractures, but various problems, such as nonunion, malalignment, and implant failure, have been reported. Simple fractures sometimes have poorer outcomes than complex fractures. We studied elderly patients with simple fracture patterns who underwent open reduction followed by placement of a single positional screw to hold the reduced interfragmentary gap, and compared these cases with patients who underwent surgery using conventional MIPO techniques. PATIENTS AND METHODS: A retrospective analysis was conducted on 80 cases of patients with distal femur fractures and simple fracture patterns (33-A1, A2, and C1). The mean age was 74 (60-90) years, and the mean follow-up period was 14 (12-25) months. Group A included 40 patients who underwent conventional MIPO technique while Group B included 40 patients who had surgery using positional screws. Interfragmentary gaps in Group B were reduced using percutaneous reduction clamps, and cortical screws were inserted to sustain the reduction. Then, locking plates were inserted using conventional MIPO techniques. RESULTS: Bony union was achieved in all 80 cases, mean initial callus formation was observed in 11 weeks (8-13 weeks), and radiological union was observed in 27 weeks (15-54 weeks). Time to initial callus formation was not different, but radiologic union was achieved in 30 weeks (18-54 weeks) for Group A and 25 weeks (15-41 weeks) for Group B (p=0.006). No differences were seen in clinical function at 1year (p=0.580). Five cases of malalignment occurred in Group A (p=0.021). The rate of union during the 1-year period was significantly higher in group B than in group A (p=0.002). CONCLUSIONS: In a distal femur fracture with a simple fracture pattern, using positional screws to sustain the reduced interfragmentary gap may achieve a more rapid union by reducing fracture gap. Though functional differences were not seen in follow-ups, patients can be expected to return to their normal lives earlier as union is achieved in a shorter time. Performing MIPO using positional screws to sustain the reduced interfragmentary gap after fracture reduction will be helpful in the treatment of simple femoral fracture.

Consequences of Avulsion Fracture of the Proximal Phalanx Caused by a Technical Failure of Hallux Valgus Surgery.

Several cases of avulsion fracture of the proximal phalanx of the big toe during the lateral capsular release procedure were observed. However, these fractures have not been reported as a complication of hallux valgus surgery. The purpose of the present study was to report the proximal phalanx base fracture as an unrecognized complication and to evaluate the clinical and radiographic consequences of this complication. We retrospectively reviewed 225 feet that had undergone hallux valgus surgery involving proximal chevron osteotomy and distal soft tissue release from May 2009 to December 2012. Of these 225 feet (198 patients), 12 (5.3%) developed proximal phalanx base fracture postoperatively. These patients were assigned to the fracture group. The remaining patients were assigned to the nonfracture group. Patients were followed to observe whether the fractures united and whether degenerative changes developed at the first metatarsophalangeal joint because of this fracture. The mean follow-up period was 36 (range 12 to 72) months. All the subjects in the fracture and nonfracture groups underwent weightbearing anteroposterior and lateral radiographs of the foot at the initial presentation and final follow-up point. The 2 groups were compared with respect to the hallux valgus angle, intermetatarsal angle, range of motion, American Orthopaedic Foot and Ankle Society score, satisfaction, and degenerative changes. No significant differences were found in age, follow-up period, hallux valgus angle, intermetatarsal angle, range of motion of the first metatarsophalangeal joint, American Orthopaedic Foot and Ankle Society score, satisfaction, and degenerative changes between the 2 groups. Ten (83.3%) of the 12 fractures healed, 2 (16.7% of the fractures, 0.89% of the operated feet) progressed to asymptomatic nonunion, and 3 (1.33%) developed first metatarsophalangeal joint degeneration. Avulsion fracture of the proximal phalanx of the big toe is an uncommon complication of hallux valgus surgery. It seems to be caused by excessive tension placed on the lateral soft tissues that attach to the base of the proximal phalanx at the time of plantarlateral soft tissue release. However, this fracture does not seem to cause significant clinical problems.