Compression-locked nailing of the humerus: A mechanical analysis

Background?In the treatment of humeral fractures, reamed nailing and compression have been reported to give higher stability. In this cadaver study, we compared the Unreamed Humeral Nail (UHN) with the (reamed) Telescopic Locking Nail (TLN) to find out whether any differences exist concerning bending and rotational stability, both with and without compression.

Methods?Nails were tested in a paired set-up with 8 pairs of fresh frozen cadaveric humeri. The nail-bone constructs were submitted to axial distraction to test compression, four-point bending and torsion. After creating a bone defect simulating an unstable fracture, bending and torsional tests were run again

Results?After cyclic loading, distraction under compression with the TLN was significantly less than with the UHN: 0.10 (SD 0.06) vs. 0.31 (SD 0.18) mm (difference = –67%, 95% CI = –84% to –37%; p = 0.01). In bending, the constructs with TLN under compression were stiffer than those with the UHN: 0.96 (SD 0.25) vs. 0.80 (SD 0.25) kN/mm (difference = 0.16, 95% CI = 0.07 to 0.25; p = 0.01). In torsion and with a bone defect, no significant differences were found.

Interpretation?Both nails are capable of resisting physiological forces acting on the humerus. The constructs with the TLN under compression are more stable in bending. Compression with an axial set screw is the more stable option.     

Interlocked intramedullary nailing of the humerus

Indications for use of the intramedullary interlocked humeral nail are: pathologic fractures, including those with severe osteopenia alone; nonunions, especially those with bone atrophy and/or marked osteopenia; and humeral shaft fractures with comminution, bone loss, or other causes of instability not controlled by conventional treatment methods. In this series, eight patients were treated by intramedullary interlocked humeral nail. Follow up ranged up to 30 months, with an average of 12 months. Five of six patients in this series who had the potential to unite their fractures did so. The remaining patient had a painless fibrous union. While the two patients with pathologic fractures of the humeral shaft caused by malignant tumors did not unite their fractures, the pain relief, functional recovery, and lack of postoperative morbidity justified the operative procedure.     

Fractures of the humerus treated by elastic nailing

The Marchetti-Vicenzi elastic nail was used in the osteosynthesis of 15 diaphyseal or metadiaphyseal fractures of the humerus, 14 cases achieved consolidation, 1 resulted in nonunion. Surgical approach was always distal, transtricipital and the nail was always locked distally. In the cases that healed, the mean radiographic consolidation time was 90 days. There were no immediate postoperative complications.     

Outcomes of intramedullary nailing for acute proximal humerus fractures: a systematic review

Background

While proximal humerus fractures remain common within the elderly population, the optimal treatment method remains controversial. Intramedullary nailing has been advocated as an effective and less invasive surgical technique. The purpose of this study is to elucidate the demographics, outcomes, and complications of intramedullary nailing for acute, displaced proximal humerus fractures.

Materials and methods

Multiple computerized literature databases were used to perform a systematic review of English-language literature. Studies that met our stated criteria were further assessed for the requisite data, and when possible, similar outcome data were combined to generate frequency-weighted means.

Results

Fourteen studies with 448 patients met our inclusion criteria. The frequency-weighted mean age was 64.3 years, and mean follow-up was 22.6 months. Females accounted for 71 % of the included patients. Three-part fractures (51 %) were most commonly treated. The overall frequency-weighted mean Constant score was 72.8, and American Shoulder and Elbow Surgeons (ASES) score was 84.3. Frequency-weighted mean forward elevation, abduction, extension, and external rotation were 137.3°, 138.4°, 33.8°, and 43.1°, respectively. The Constant score for two- and three-part fractures was significantly higher than for four-part fractures (p = 0.007 and p = 0.0009, respectively). The reoperation rate for two-, three-, and four-part fractures was 13.6, 17.4, and 63.2 %, respectively.

Conclusions

Intramedullary nailing of acute, displaced two- and three-part proximal humerus fractures yields satisfactory clinical outcomes, although reoperation and complication rates remain high. Use of this implant for four-part fractures cannot be recommended until further clinical studies with larger patient numbers are available.

Level of evidence

Level IV, Systematic review.

     

Rotational alignment of humerus after closed locked nailing

OBJECTIVE: Rotational malalignment that may happen during closed nailing of humeral fractures is, to date, an unexplored area of investigation. The purpose of this study was to examine the effect of arm position during surgery on humeral rotational alignment and the effect of this alignment on shoulder motion and function. METHODS: Thirty patients with eventual fracture healing after closed humeral locked nailing were retrospectively studied: 15 had retrograde nailing; 15, antegrade. Retrograde nailing was performed with the patient in a decubitus position and with the upper arm anteriorly flexed and the forearm perpendicular to the operating table. Antegrade nailing was performed with the patient in a semisitting position and with the upper arm in the so-called resting position. The humeral retroversion angle as measured by computed tomographic scan, range of shoulder rotation, and Neer score of the shoulder for the fractured and the intact humeri were determined, and the discrepancy (i.e., value for the intact subtracted from that for the fractured) between the two was noted. To test the effect on alignment of positioning during retrograde nailing, we similarly determined retroversion angles for another 15 patients treated in a supine resting position. RESULTS: Between antegrade nailing and retrograde nailing in decubitus position, there was a significant difference in the mean discrepancies for the retroversion angles and the range of external rotation of the shoulder in the neutral and abduction positions, but no significant difference for internal rotation of the shoulder and Neer score. Between antegrade nailing and retrograde nailing in supine resting position, there was no significant difference in the mean discrepancy for the retroversion angle. CONCLUSION: Positioning of the arm may significantly affect humeral rotational alignment and range of motion during closed nailing. Until a reliable method for intraoperative measurement of humeral rotation is devised, we recommend that closed nailing of humeral shaft fractures be performed with the patient's upper arm in the resting position shown in this study.     

Antegrade intramedullary nailing of the humerus complicated by heterotopic ossification of the deltoid: a case report

A case of antegrade nailing of the humeral shaft in a polytrauma patient was complicated by heterotopic ossification of the lateral deltoid muscle and severe loss of shoulder motion. The patient did not respond to physiotherapy alone and was successfully managed by excision of the heterotopic bone and adjunctive radiation therapy.     

Intramedullary nailing of displaced four-part fractures of the proximal humerus

BackgroundIntramedullary nailing is already established technique for the treatment of two and three-part fractures of proximal humerus. The aim of the study was to prospectively evaluate the efficacy and functional outcome after treatment of four-part fractures of proximal humerus with Multiloc proximal humeral nail.Designprospective monocentric cohort study.Settingsingle level 1 traumacenter.Materials and MethodsFrom February 2011 to March 2016, 40 patients with displaced four-part proximal humeral fractures were treated with intramedullary nail inserted through anterolateral approach. Minimum one year follow up completed 35 patients and were involved into the study.ResultsAfter mean follow up period of 25.8 months 29 of 35 fractures healed. Average absolute Constant score in all 35 patients reached 57.7 points, relative side related Constants score 66.8% of contralateral extremity. Together there were 20 complications. in 6 cases (17%) developed complete avascular necrosis of the head. One deep infection was treated by implantation of antibiotic cement discs. Twelve secondary surgeries were performed, mostly for avascular necrosis development. Function and pain were significantly influenced by the quality of fracture reduction (p < 0.05) and development of complete AVN (p = 0.001). Group of 29 patients without AVN reached relative Constant score 73% of contralateral extremity.ConclusionsIntramedullary nailing can be used as possible fixation technique for the treatment of four-part fractures of proximal humerus. In experienced hands provides nailing osteosynthesis similar results as reconstruction with locking plates. Appropriate reduction of fracture fragments is the key for good functional result.Level of evidenceLevel 2b – monocentric prospective cohort study.     

The Fixion nailing system for stabilising diaphyseal fractures of the humerus: a two-year clinical experience

Previous studies have shown that the expandable nail system (Fixion) can provide rapid stabilisation of long bone fractures with reduced operative time and low complication rates. Patients with humeral shaft fracture were treated consecutively over a two-year period in our institution with the Fixion nail. Nineteen Fixion nailings were performed in 16 patients over a 2 year period. All fractures were diaphyseal and closed. Eight primary fracture stabilisations were performed and we recorded 2 nonunions in this group, both associated with rotational instability at the fracture site. Six nailings were performed in 4 patients for fracture non-union with a mean operative time of 127.5 minutes. One case did not unite despite 3 separate Fixion nailing procedures. Five operations were performed for a pathological fracture, with a mean operative time of 79 minutes; they all united. We did not experience advantages of this nail as mentioned in previous studies and the complication rate was higher than previously stated.     

Locked plate fixation and intramedullary nailing for proximal humerus fractures: a biomechanical evaluation

BACKGROUND: Internal fixation of proximal humeral fractures is associated with a considerable secondary malalignment rate. Fixed-angle implants have been suggested to increase the stability of fixation. METHODS: The biomechanical properties of four different implants were tested. These included an internal fixator with semi-elastic properties (reference), the Synthes T-plate, a locked plate with rigid properties and a spiral blade locked intramedullary nail (PHN). These implants were assessed in twenty-four osteotomized pairs of human cadaveric humeri. Specimens were subjected to two-hundred cycles of axial loading and torque followed by load to failure. RESULTS: The PHN had greater axial stiffness than the reference and the T-plate. During torque, all implants were stiffer than the reference. During cyclic loading, there were no differences between the T-plate and the reference. Both the rigid internal fixator and the PHN had less irreversible deformation than the reference. Both implants resisted higher loads before failure. CONCLUSION: This study showed that the proximal humeral nail and the rigid internal fixator are stronger than the semi-elastic locked plate and the Synthes T-plate for unstable subcapital proximal humeral fractures.     

An expandable nailing system for the management of pathological humerus fractures

BACKGROUND: People with metastatic fracture of the humerus are of poor general health. Often they are not able to compensate the handicap of an impaired extremity. Standard osteosynthetic techniques are not always applicable. To reduce the trauma of the operation, we used the Fixion expandable nail system. METHODS: At two centers, 23 metastatic fractures of the humerus (in 22 patients) were stabilized with a new nailing system. The nail expands under hydraulic pressure up to 150% of its uninflated diameter, gaining long frictional contact to the bone. All patients were followed up until osseous healing occurred or until they died. RESULTS AND CONCLUSIONS: The operative time was approximately 32 min, including 1.4 min fluoroscopy time. Nail insertion is brief and therefore not very stressful to the group of debilitated patients who require this intervention. Immediately postoperatively, the upper extremity is stable to permit physiotherapy. In these few patients, we saw no complications. The advantages of the surgical approach appear to outweigh those of conservative management options if a simple and safe surgical technique makes the humerus stable enough to resist normal daily loads.     

带锁髓内钉治疗526例长骨骨折疗效分析

目的评价带锁髓内钉治疗股骨、胫骨和肱骨骨折的疗效。方法回顾性分析自1994年4月至2003年9月应用带锁髓内钉治疗长骨骨折546处(526例)。男430处(412例)，女116处(114例)；平均年龄36．4岁。新鲜闭合骨折432处，开放骨折38处；陈旧骨折76处。手术利用“C”型臂或“G”型臂行闭合复位或切开复位内固定。其中闭合复位194处，切开复位352处；扩髓485处，未扩髓61处；静力型固定539处，动力型固定7处；顺行髓内钉固定519处，逆行髓内钉固定27处。结果平均随访时间31．6个月(9～123个月)，543处骨折获得愈合，愈合率为99．5％，骨折平均愈合时间为4．4个月。其中531处(97．2％)一期愈合，12处(2．2％)二期愈合。延迟愈合11处(2．0％)，10处经动力化，1处维持外固定和制动，均获得骨性愈合；骨折不愈合4处(0．7％)，1处经更换带锁髓内钉后骨折愈合；畸形愈合3处(0、5％)；感染5处(0．9％)；外伤性骨折2处(0.4％)；内固定失败7处(1、3％)，其中主钉断裂3处，远侧锁钉弯曲或退出4处。髋周异位骨化9处；桡神经轻瘫1例；肺栓塞1例。股骨或胫骨骨折患者，术后肩、膝、髋关节功能活动优良，术后膝前痛15例，肩部疼痛6例。结论带锁髓内钉是治疗股骨、胫骨和肱骨骨折的一种较好的方法。新鲜长骨骨折尽可能闭合复位、陈旧骨折切开复位，均采用静力固定，根据骨折部位和伤情选择是否扩髓。术后正确指导功能锻炼等是治疗成功的关键。     

Numerical evaluation of the mechanical properties of a novel expandable intramedullary nailing: A new alternative to standard interlocking nailing

Introduction: There has been a great effort in preventing the disadvantages of distal locking in intramedullary nailing to date. From this scope, a novel expandable nail fixation eliminating distal locking screws has been designed. The primary aim of this numerical parametric study is to investigate mechanical behavior of expandable nail fixation on the fractured femur model under different contact parameters which are effective in maintaining the nail position and to specify the appropriate values of these contact parameters for a safe fixation. The second aim is to compare mechanical behavior of the expandable nail fixation with the standard interlocking nail fixation.Materials and Methods: The expandable nail has three wedges which are responsible for distal fixation by compressing the medullary canal in the radial direction. 4th generation Sawbones femur model was used as bone model. A transverse osteotomy with 20 mm gap was created to simulate a subtrochanteric fracture. The fixations have been examined under axial compression with 1200 N and torsion with 7 Nm. In the parametric study, the tightening torque and static friction coefficient in wedge-canal contact were selected as contact parameters. The outputs were stiffnesses of the fixations, equivalent von-Mises stress distribution on the models, and load sharing between the canal and distal locking elements.Results: The results of the parametric study showed that the model with the tightening torque of 3 Nm and friction coefficient of 0.7 was the safest. The load borne by wedges is generally prone to increase with increased tightening torque and friction coefficient. The both fixations showed close stiffness and stress values.Conclusion: The tightening torque of the wedge locking mechanism is directly effective in maintaining the nail position constant in canal, and the safety of the fixation is better ensured with increased tightening torque but stress states on bone must be carefully evaluated. The expandable nail provided comparable results to standard interlocking nails with respect to the fixation stiffness, stress, and contact forces. The expandable nailing may be evaluated as an alternative in the fractures of long bones in the case that the numerical results are supported by future experimental studies.     

New technique for humerus shaft fracture retrograde intramedullary nailing

Humeral shaft fracture intramedullary nailing is less invasive than plates and screws. Antegrade technique has postoperative shoulder pain, increased rehab time, and frequent reoperation for rod removal. Published retrograde technique is not collinear with the shaft, has insertion site fractures (5% to 15%), and radial nerve palsies (5%). Our retrograde technique is collinear with the humerus shaft, simpler, and decreases operative fracture risk. The supine patient's elbow is fully flexed. A guide pin is inserted through the triceps tendon to the olecranon fossa roof, aligned with the humerus shaft, and drilled thought the cortex followed by the 6.5 mm cannulated drill through a small triceps splitting incision. The guide pin is passed along the humerus shaft and across the fracture. A small incision is made to identify and protect the radial nerve during reduction, reaming, and rod insertion. Flexible reamers are used and the nail placed and locked at least distally to prevent distal migration. An institutional review broad approved retrospective review of Louisiana State University Health Sciences Center adult humeral shaft fractures with retrograde technique from 1999 to January of 2009 was carried out. Sixteen patients were treated without perioperative fracture or nerve palsy.     

Treating multifocal humerus fractures: A comparison between the mipo technique and intramedullary nailing

Introduction and objectiveProximal humerus fractures with metaphysodiaphyseal extension represent a challenge for the orthopedic surgeon due to their reduced incidence and the difficulty in the treatment decision. These can be treated with an intramedullary nail or using the MIPO technique, associating different advantages and complications depending on the procedure. The objective of this study was to compare metaphyseal-diaphyseal fractures of the humerus treated with antegrade intramedullary nailing and those operated using the MIPO technique to see if there were significant differences in terms of functional, clinical, and radiological results.Material and methodsretrospective, analytical and unicentric review of 29 patients with proximal fracture with metaphyseal-diaphyseal extension treated by MIPO technique and 33 patients surgically treated by antegrade intramedullary nailing (IMN) in our hospital from 2014 to 2020. Demographic, functional, radiographic and clinical data were obtained..ResultsNo significant differences were observed between both groups in terms of fracture mechanism (p=0.34), fracture type (p=0.13) or Maresca classification (p=0.32). Surgical time was significantly shorter in the IMN group compared to the MIPO technique (p=0.014). No significant difference was observed regarding the need for blood transfusion (p=0.32). The mean consolidation in the MIPO group was 21 weeks compared to 21 weeks in the IMN, with no significant differences between both groups (p= 0.88). No significant differences were observed between CONSTANT test at one year in the MIPO group versus the IMN group (p=0.79), nor in radial nerve palsies (p=0.28).ConclusionsProximal fractures with metaphyseal-diaphyseal extension are a challenge for the orthopedic surgeon due to the infrequency, the complexity of these fractures and the fact that there is no established consensus on the ideal treatment for this type of injury. Both the MIPO technique with the Philos plate and the intramedullary nail are valid options for the treatment of these fractures, with no differences observed in terms of fracture consolidation time or in terms of functional results.