Straight Nails Research Articles

Estimating the optimal entry point of the antegrade femoral nailing: Previous and novel morphometric measurements.

This anatomical study aimed to investigate the possible relationships between the proximal femur parameters and verify the optimal entry point in line with the medullary canal. Both in single image series and 3D-MPR views, 63 femur bones were evaluated. One-millimeter multidetector computed tomography scans were collected and assessed by OsiriX-Lite version 8 and Horos v3.3.5. Entry point locations, projected and true femoral neck-shaft, anteversion, and newly defined nail entrance angles were measured. The entry points of 16 femurs were placed at the tip of the greater trochanter, and the remaining 47 femurs were in the trochanteric fossa (i.e., piriformis fossa). Thirty-three of the entry points found in the trochanteric fossa were overlapped by the greater trochanter. When the parameters of the right and left sides were compared, it was found that; projected neck angle, nail entrance angle, and the differences between true neck angle and nail entrance angle were found significantly different. The relationship between nail entrance angle and entry point localization was assessed, and the probability of the entry point being at the tip of the greater trochanter is 63 times greater when the NEA is below 90. This study has demonstrated that the ideal entry point for straight nails, which is based on the anatomic axis of the femur, is found mainly at the trochanteric fossa, and the greater trochanter overlapped 70.21% of them. Level IV, Diagnostic Study.

Newer generation straight humeral nails allow faster bone healing and better functional outcome at mid-term

PurposeAlthough proximal and diaphyseal humerus fractures are frequent, the optimal management remains controversial. Antegrade nailing prevents further damage to the soft tissues and to the vascularization, but it has been associated with postoperative shoulder pain and dysfunction. During the latest years a straight nail design was developed to minimize these problems.MethodsA total of 243 patients who had undergone surgery for antegrade intramedullary humeral nailing between January 2013 and July 2018 in A. Gemelli Trauma Center were divided into two groups according to the nail design used: straight nail group (S-group) and curvilinear nail group (C-group). Clinical data were collected using assessment forms (SF12-v2, Quick-DASH, ASES and Constant-Murley). Radiographic bone healing was assessed with RUST score at 30, 90 and 180 days after surgery.ResultsThe S-group was made up of 128 patients with a mean age of 59 ± 19 (range 18–97) and a mean follow-up of 46 ± 9 months. The C-group was made up of 115 patients with a mean age of 53 ± 16 (range 18–88) and a mean follow-up of 51 ± 8 months. The S-group had a mental component summary (MCS) score of 54.3 ± 7.7 and a physical component summary (PCS) score of 46 ± 10.2, the C-group had a MCS score of 50.9 ± 8.4 and a PCS score of 44.1 ± 7.4. Quick-DASH and ASES were respectively 18.8 ± 4.3 and 78.6 ± 8.2 in the S-group, 28.3 ± 11.6 and 72.1 ± 13.5 in the C-group with statistical significance. Constant-Murley score was 73.9 ± 9.1 in the S-group (76% of the contralateral healthy side) and 69.4 ± 10.4 in the C-group (73% of the contralateral healthy side). The radiographic union score in the S-group was 4.1 ± 0.3 at 30 days after surgery, 7 ± 0.8 at 90 days and 10 ± 1.2 at 180 days, while in the C-group it was 4.2 ± 0.4 at 30 days, 6.4 ± 0.7 at 90 days and 9 ± 0.9 at 180 days.ConclusionNewer generation straight nails allow a faster bone healing and better functional outcome at mid-term follow up.Level of evidence III.

Subtalar Nonunion Following Tibiotalocalcaneal Fusion Using an Intramedullary Nail: A Case Series of Errant Entry Points

Category:HindfootIntroduction/Purpose:Tibiotalocalcaneal (TTC) arthrodesis is a procedure used to treat hindfoot deformity and/or arthritis. Retrograde intramedullary nails have been used as a method of fixation. The nails are either straight or have a bend to accommodate valgus alignment of the hindfoot. Studies comparing nail types or analysis of nonunions are lacking in the available literature on the subject despite a reported nonunion rate of up to 20%. The purpose of this study was to report a series of subtalar nonunions that all had an entry point that was too medial on the calcaneus resulting in inadequate purchase of the nail in the calcaneus.Methods:Six cases of subtalar nonunion were retrospectively reviewed. All were referred for second opinion. Evaluation consisted of examination, radiographs and CT scans. Patient demographics, comorbidities and findings common to all cases were recorded.Results:Presenting complaints in all cases were persistent swelling. Non-neuropathic cases all had hindfoot pain. In this series, all the implants were straight nails. Radiographs and CT scans revealed that all cases were done for severe valgus deformity with subtalar subluxation. In each of the cases, the deformity was under corrected and the nail entry point was too medial on the calcaneus which resulted in reaming out the medial wall of the calcaneus, decreasing the amount of fixation obtained with the nail. In each of the cases, the medial wall of the calcaneus was deficient and the nail had no medial containment.Conclusion:Severe valgus deformity with subtalar subluxation is a risk factor for subtalar nonunion when the deformity is under corrected and a straight nail is used. Ensuring that the tibia talus and calcaneus are collinear and that the entry point in the calcaneus is sufficiently lateral are important factors to consider when addressing this type of deformity. Accurate intraoperative imaging is essential to ensure proper positioning of the entry point to avoid reaming out the medial wall of the calcaneus and to ensure adequate purchase of the nail in the calcaneus.

Tibiotalocalcaneal Arthrodesis Using a Straight Intramedullary Nail

Category: Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis using a hindfoot intramedullary nail has been shown to be a safe and reliable technique in patients with severe ankle and hindfoot disease. There is debate about the use of straight nails versus curved nails. Proponents of the curved nail argue that straight nails predispose to greater risk of lateral plantar nerve injury, poor calcaneal bone purchase and inability to maintain satisfactory hindfoot valgus alignment. However, the subtalar joint is a condyloid joint enabling rotation of the talus on the calcaneum to create varus/valgus position of the calcaneal tuberosity. We present a clinical series of patients undergoing TTC fusion using a straight nail assessed by clinical and radiological outcomes to establish whether theoretical risks of straight nails are reflected in clinical practice. Methods: This single centre, retrospective study of prospectively collected data on a sequential series of patients to undergo TTC fusion, with pre and post-operative weight bearing CT imaging. Data was collected on indication for procedure, co-morbidities, post-operative complications, union rate as well as clinical scores, EQ5D and MOXFQ. Weight bearing CT imaging was analysed using the validated TALUS™ (torque ankle lever arm system) method on weight bearing CT, providing calcaneal offset, hindfoot angle and hindfoot alignment. These were used as markers of hindfoot alignment. Results: 65 patients (37 males, 28 females) were included in the study, with an average age of 57 years. Average follow-up was 20 months. Indications for TTC fusion included Charcot arthropathy, talar avascular necrosis, post traumatic arthritis and non-union of previous arthrodeses. Union rate was 91% (59/65). Overall complication rate was 11% (7/65) and most were minor wound complications. There were no plantar nerve injuries noted. There were no nail cut outs from the calcaneum. On all markers of hindfoot alignment, cases showed a more physiological degree of hindfoot valgus compared to pre-operative measures. There were significant improvement in both EQ5D and MOXFQ scores (p<0.05). Conclusion: We present the largest series of TTC fusion using a straight intramedullary nail and the first series to analyse hindfoot alignment using weight bearing 3D CT imaging. Our data regarding correction of hindfoot alignment is supported by biomechanical theories of subtalar varus/valgus, being related to rotatory changes at the subtalar joint, questioning the perceived need for a curved nail. This is particularly at the level of the entry point of the nail. The principles of valgus hindfoot nails are based on biomechanical laboratory studies and cadaveric studies, neither of which reflect our findings in clinical practice.

The female geriatric proximal humeral fracture: protagonist for straight antegrade nailing?

IntroductionStraight antegrade humeral nailing (SAHN) has become a standard technique for the surgical fixation of proximal humeral fractures, which predominantly affect elderly females. The nail’s proximal anchoring point has been demonstrated to be critical to ensure reliable fixation in osteoporotic bone and to prevent iatrogenic damage to the superior rotator cuff bony insertion. Anatomical variations of the proximal humerus, however, may preclude satisfactory anchoring of the nail’s proximal end and may bare the risk of rotator cuff violation, even though the nail is inserted as recommended. The aim of this study was to evaluate the anatomical suitability of proximal humeri of geriatric females aged 75 years and older for SAHN. Specifically, we sought to assess the proportion of humeri not anatomically amenable to SAHN for proximal humeral fracture.Materials and MethodsA total of 303 proximal humeri of 241 females aged 75 years and older (mean age 84.5 ± 5.0 years; range 75–102 years) were analyzed for this study. Multiplanar two-dimensional reformations (true ap, true lateral, and axial) were reconstructed from shoulder computed tomography (CT) data sets. The straight antegrade nail’s ideal entry point, “critical point” (CP), and critical distance (CD; distance between ideal entry point and CP) were determined. The rate of proximal humeri not anatomically suitable for SAHN (critical type) was assessed regarding proximal reaming diameters of currently available straight antegrade humeral nails.ResultsOverall, 35.6% (108/303) of all proximal humeri were found to be “critical types” (CD <8 mm) as to the recommended minimal proximal reaming diameter of 10 mm of straight antegrade nails currently in use. Moreover, 43.2% (131/303) of the humeri were considered “critical types” with regard to the alternatively used larger proximal reaming diameter of 11.5 mm. Mean CD was 9.0 ± 1.7 mm (range 3.5–13.5 mm) and did not correlate with age (r = −0.04, P = 0.54). No significant differences in CD and rate of “critical types” were found between left and right humeri as well as between females aged between 75 and 84 years (n = 151) and females aged 85 and older (n = 152).ConclusionsMore than a third of proximal humeri of geriatric females are “critical types” as to SAHN and may, therefore, be at risk for procedure-related complications, such as rotator cuff violation, fixation failure, and potential malreduction. In view of this finding, we recommend to routinely analyze multiplanar CT reformations of the uninjured contralateral side prior to surgery to improve selection of patients for SAHN and to minimize foreseeable complications. For “critical type” humeri, an alternative surgical procedure should be considered.

Biomechanical evaluation of straight antegrade nailing in proximal humeral fractures: the rationale of the \u201cproximal anchoring point\u201d

PurposeVarus failure is one of the most common failure modes following surgical treatment of proximal humeral fractures. Straight antegrade nails (SAN) theoretically provide increased stability by anchoring to the densest zone of the proximal humerus (subchondral zone) with the end of the nail. The aim of this study was to biomechanically investigate the characteristics of this “proximal anchoring point” (PAP). We hypothesized that the PAP would improve stability compared to the same construct without the PAP.MethodsStraight antegrade humeral nailing was performed in 20 matched pairs of human cadaveric humeri for a simulated unstable two-part fracture.ResultsBiomechanical testing, with stepwise increasing cyclic axial loading (50-N increments each 100 cycles) at an angle of 20° abduction revealed significantly higher median loads to failure for SAN constructs with the PAP (median, 450 N; range, 200–1.000 N) compared to those without the PAP (median, 325 N; range, 100–500 N; p = 0.009). SAN constructs with press-fit proximal extensions (endcaps) showed similar median loads to failure (median, 400 N; range, 200–650 N), when compared to the undersized, commercially available SAN endcaps (median, 450 N; range, 200–600 N; p = 0.240).ConclusionsThe PAP provided significantly increased stability in SAN constructs compared to the same setup without this additional proximal anchoring point. Varus-displacing forces to the humeral head were superiorly reduced in this setting. This study provides biomechanical evidence for the “proximal anchoring point’s” rationale. Straight antegrade humeral nailing may be beneficial for patients undergoing surgical treatment for unstable proximal humeral fractures to decrease secondary varus displacement and thus potentially reduce revision rates.

Clinical outcomes and prognostic factors depending on implant design in the treatment of proximal humeral fractures: A retrospective study

PurposeWe aimed to examine the clinical outcomes of proximal humeral fractures treated with different intramedullary nail shapes. MethodsThirty-seven patients were divided into two groups depending on the implant shape. We also defined F group as a subgroup of fracture classification. ResultsIn the F group, the flexion of the shoulder joint was significantly greater in S (mean, 134.6°) than in C groups (mean, 109°) (p=0.04). The complication rate was significantly larger in the C group (p=0.04). ConclusionsPatients with one kind of fracture and who were treated with straight nails had better outcomes.

The importance of reaming the posterior femoral cortex before inserting lengthening nails and calculation of the amount of reaming.

BackgroundLengthening nails have been used to correct limb length discrepancy caused by different etiologies, as well as for post-traumatic reasons. Two important lengthening nail-related complications are damage to the distraction mechanism and femoral fractures around the nail tip. As a result of the curved anatomy of the femur, straight nails impinge on the anterior cortex. Therefore, proper reshaping of the medullary canal to accommodate straight lengthening nails is crucial for the prevention of this problem. Reaming the dense posterior cortex is important when aiming to insert a lengthening nail without incurring anterior cortex nail tip impingement-related complications. Posterior femoral cortex over-reaming is a solution to this situation.MethodsSixty patients received lengthening nails during 2008–2013, (ISKD, Fitbone, Precice). Posterior cortex rigid-reaming technique was used successfully in 45 retrograde femoral lengthening cases. The preoperatively planned posterior cortex amount was reamed until the impingement was overcome during the operation under fluoroscopic control for each case. Since the preoperative determination of posterior cortex reaming amount is time consuming and operator dependent, we evaluated the X-rays of the patients with computer software and conventional paper-based measurements. The effect of reaming the posterior cortical wall on the inclination of the nail tip to the anterior femoral cortex was detected with measurements on the preoperative and postoperative lateral femoral X-rays by using the CorelDRAW® Graphic Suite X6 software package (Corel, Inc., Ottawa, Ontario, Canada) software. On the same software, X-rays and the posterior reaming amount were also calculated.ResultsThe mean age of the patients was 27 years (11–42), while the mean lengthening was 5.9 cm (2–14). The mean consolidation index was 1.05 (0.75–1.62), and the mean follow-up period was 31 months (range, 18–45 months). The mean distance of the osteotomy site to the intercondylar notch of the femur was 81.2 mm (±16.92). The mean displacement of the nail tip position was 15.42 mm (±4.77) on the measurements on the postoperative X-rays after nail insertion compared to the preoperative simulations on the templates. The mean posterior cortex reaming thickness was 3.68 mm (±1.02).ConclusionsWe derived a formula that allows the required amount of optimal posterior cortex reaming to be determined. No impingement-related complications or nail damage were observed.

Cephalomedullary nails: factors associated with impingement of the anterior cortex of the femur in a Hispanic population.

Impingement and penetration of the anterior cortex of the femur have been reported as complications after cephalomedullary nailing. The purpose of this study was to determine factors related to nail impingement in our population of Hispanic patients. A non-matched case-control study was carried out and 156 patients who underwent cephalomedullary nailing from 2010 and 2013 were included; 78 cases with anterior cortical impingement and 78 control cases without impingement were documented. Demographic variables and specifications of the nails such as manufacture and radius of curvature were recorded. The presence of impingement, angle of incidence on radiographs--indirect measurement of the femoral bow on the sagittal plane--and nail entry site were determined. Bivariate and multivariate logistic regression analyses were performed to identify the factors associated with cortical impingement. The distribution by sex corresponded to 87 females (56%) and 69 males (44%) with a mean age of 75 years [SD 18.2]. Cortical impingement was presented in 78 cases (50%) and 6 (3.8%) patients evidenced penetration of the anterior cortex of the femur. On the bivariate analysis the posterior nail start site is highlighted, which showed a positive association with impingement (OR 4.3; 95% CI 1.1-36 and p = 0.04). After the multivariate analysis, the factors associated with anterior cortical impingement included female gender (OR 2.2; 95 % CI 1.1-4.6 and p ≤ 0.038), straight nails-short nails-(OR 4.9; 95% CI 2.2-10 and p ≤ 0.001) and angle of incidence ≥7° (OR 4.9; 95% CI 2.2-10 and p ≤ 0.001), the latter showing a likelihood of 57 % for impingement, increasing to 90% with an angle of incidence of 11°. Posterior entry site should be avoided and an anterior site should be used. Female gender, straight nails and greater angle of incidence of the femur were associated with cortical impingement. A specific intramedullary nail design is needed for the Hispanic population due to high impingement and anterior cortical penetration rates seen with conventional nails. Short curved nails and long nails with a lower radius of curvature are required.

Tibiotalocalcaneal arthrodesis using a straight intramedullary nail.

Tibiotalocalcaneal (TTC) arthrodesis is a proven solution for severe hindfoot arthropathy that reestablishes stability for plantigrade gait and alleviates pain, while correcting deformity. Intramedullary nailing is an effective option for fixation. The aim of this study was to determine clinical outcome, analyze the fusion rate, and determine final hindfoot alignment in a consecutive series of patients using a single-design straight intramedullary nail. This study evaluated 63 patients treated between 2006 and 2010 with at least 36 months of follow-up. Ten patients were excluded because of study inclusion criteria, and 4 were lost to follow-up, leaving 49 patients available for review. The average follow-up was 70.7 ± 15.1 months. The American Orthopaedic Foot and Ankle Society score improved from 29.7 ± 15.1 before arthrodesis to 65.8 ± 14.6 after (P < .001) with 83.7% (41/49) of patients stating they were satisfied or very satisfied with the outcome. The hindfoot angle improved from -3 ± 15 degrees (varus) before the arthrodesis to 3.5 ± 4 degrees (valgus) after; the tibiotalar angle averaged 103 ± 4.2 degrees after the arthrodesis. Fusion occurred in both joints in 86% (42/49) of patients and in 93% (91/98) of all joints. The average time to fusion was 4.5 ± 2 months. Current smokers had a significantly (P = .03) higher risk of complications. Use of an allograft, with or without bone morphogenetic protein 2, led to comparable results even in the presence of a large bone defect. These results are comparable to previously published studies using intramedullary nailing to achieve tibiotalocalcaneal arthrodesis. The complication concerns typically associated with straight nails were not found. We recommend using a retrograde intramedullary nail for the fixation of TTC arthrodesis and adding an allograft in cases of significant bone loss. Level IV, consecutive case series.

Pre-requisites for optimum centering of a tibiotalocalcaneal arthrodesis nail.

Purpose of study was to compare nail alignment, incidence of stress riser and fracture with straight and curved nails of different lengths. We conducted a retrospective review of consecutive, initially 13 straight and subsequently 15 curved nails implanted in 17 men and 11 women. Angles of incidence and reflection subtended by nail tip with inner tibial cortex were measured. Cortical hypertrophy was assessed on follow-up radiographs. Angles of incidence and reflection were greater with short straight nails, less with long straight nails and stayed close to zero with long curved nails. Stress fractures occurred in 2 patients with straight nails at the level of the proximalmost tibial screw. Cortical hypertrophy was present in 7 patients with straight nails and in only 1 patient with a curved nail (p=0.01). Both nail length and inbuilt valgus contribute to better central positioning within the tibia. However, cortical stress reactions occur less frequently with curved nails.

Straight proximal humeral nails are surrounded by more bone stock in comparison to bent nails in an experimental cadaveric study

BackgroundIn the management of proximal humeral fractures intramedullary implants with bent and straight shape of the proximal part of nail are available. Based on data from previous studies on bone distribution in the humeral head, we hypothesized, that higher densities might exist in the bone stock surrounding straight nails in comparison to their angulated counterparts. With a known positive correlation between bone density and mechanical stability, this could indicate potentially higher rigidity of osteosyntheses done with straight implants.MethodsWe performed high resolution peripheral quantitative computed tomographies of the potential straight and bent implant bearing regions of 27 cadaveric proximal humeri. The acquired data were analyzed for differences between straight and bent Volumes of Interest as well as intra- and interindividual bone stock distribution.ResultsFor both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction. Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p < 0.01) Intra-individual comparison yielded high bivariate correlations of the corresponding Volumes of Interest of the right and the left side (p < 0.01).ConclusionsBased on the volumetric data a statistically relevant biomechanical superiority of straight shaped implants can be assumed. Since we found a rapid decrease of bone density in cranio-caudal direction, intramedullary implants should be anchored as proximally in the subcortical area as possible to minimize the risk of displacement or cutout. The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

The Use of Intramedullary Nails in Tibiotalocalcaneal Arthrodesis

Tibiotalocalcaneal arthrodesis is a salvage procedure undertaken for hindfoot problems that affect both the ankle and subtalar joints (eg, two-joint arthritis, severe acute trauma, osteonecrosis of the talus, severe malalignment deformities, significant hindfoot bone loss). Methods of achieving fusion include Steinmann pins, screws, plates, external fixators, and retrograde intramedullary nailing. Retrograde intramedullary nailing provides a load-sharing fixation device with superior biomechanical properties and is an excellent choice for use in tibiotalocalcaneal arthrodesis. This technique can be performed through relatively small incisions. In addition, recent design modifications include the availability of dynamization and the choice of curved or straight nails. Contraindications to the technique include the presence of infection, severe vascular disease, and severe malalignment of the tibia.

Multiple Self-inflicted Nail Gun Head Injury

Penetrating brain injury resulting from nail-gun use is a well-characterized entity, one that is increasing in frequency as nail guns become more powerful and more readily available to the public. We present a case and offer management strategies for a 50-year-old male with two intracranial penetrating nail gun injuries. Nail gun brain injuries are commonly intentionally self-inflicted. Suicide should be considered when straight nails cause wounds to the chest, head, or abdomen. The primary preoperative concern is formation of a traumatic pseudoaneurism, which prompts both preoperative and follow-up cerebral angiography. Surgery for combined intracranial and extracranial injury may require the collaborative expertise of colleagues from the fields of ophthalmology, otolaryngology, and oral maxillofacial surgery. A rational management strategy should permit these patients to be discharged with no additional injury.

Trochanteric Nail Insertion for the Treatment of Femoral Shaft Fractures

This study was designed to evaluate whether the use of a new femoral nail, specifically designed to be inserted through the greater trochanter, could eliminate the complications previously seen with insertion of straight nails through this entry portal for the treatment of femoral shaft fractures. Prospective, clinical trial. Three level I trauma centers. Sixty-one consecutive patients with femoral shaft fractures (50 closed and 11 open fractures) treated with antegrade nailing with insertion through the greater trochanter. All patients were treated in the supine position with a TAN nail (Trigen System, Smith & Nephew, Memphis, TN) inserted through the greater trochanter. Union, alignment, complications, and hip function. Forty-six of 57 (81%) surviving patients were available for follow-up at a minimum of 12 (range, 12-25) months. Union occurred in all but 1 fracture after the index procedure. No patient sustained iatrogenic fracture comminution, and there were no angular malunions. Pain was reported as slight in 6 patients and moderate in 2. Visual and videotaped gate analysis, performed on 24 patients, revealed symmetrical walking in 21. This study demonstrates that antegrade nailing of femoral shaft fractures with a specially designed nail inserted through a trochanteric starting point provides predictably high union rates and low rates of complications. Ease of entry and utility in patients with a large body habitus are advantages over conventional piriformis fossa entry techniques. Nailing through the greater trochanter with the patient supine is presently our treatment of choice for patients with femoral shaft fractures.

Mechanical Properties of Different Combinations of Flexible Nails in a Model of a Pediatric Femoral Fracture

Flexible nailing of pediatric femoral shaft fractures is based on the principle of using two C-shaped nails to create six points of fixation. However, clinical studies using various nail combinations demonstrate similar outcomes. This study aimed to compare the mechanical properties of different nail combinations by testing them in a model of a child's midshaft femoral fracture. The two C-shaped nails were compared with two straight nails and with paired S- and C-shaped nails. The constructs were tested in four-point bending and torsion. Graphs of the data were produced, from which the bending and torsional stiffness of the constructs was calculated. The results showed that there was no significant difference between the mechanical properties of the three different constructs. The conclusion is that any of the tested nail combinations can be used to treat a midshaft fracture of the femur in a child.

Comparison of the bone modeling effects caused by curved and straight nickel-titanium intramedullary nails.

Nitinol (NiTi) shape memory metal alloy makes it possible to prepare functional implants. A curved intramedullary NiTi nail has been shown to cause bending of the bone, bone thickening, increase in cortical area, and reduction in bone longitudinal growth. The purpose of the present study was to find out whether these changes are caused by the bending force of the curved nail or by the intramedullary nailing itself. Pre-shaped intramedullary NiTi nails were implanted in the cooled martensitic form into the medullary cavity of the right femur in 12 rats, where they started to restore their austenitic form, causing a bending force. Straight nails were used as controls in another 12 rats. After 12 weeks, the operated femurs were compared with their non-operated contralateral counterparts and the differences were compared between the groups. Anteroposterior radiographs demonstrated bone bowing only in the curved nail group. Retardation of longitudinal growth was observed in both groups, showing that the growth effect seems to be due to the intramedullary nailing itself. Increase in bone cross-sectional area and cortical thickness were found in both groups. However, this increase was more evident with the curved nail, indicating that the bending force of the functional nail seems to induce these changes.

Axial Fixation of Forearm Fractures

Thirty-five patients with fractures of the shafts of the forearm bones were treated over a six-year period. The results in thirty-two of these patients with fifty fractures were evaluated for study. Treatment of these fractures consisted in early open reduction and internal fixation with square, snug-fitting, somewhat flexible, straight intramedullary nails which were introduced by a simple technique. Five patients were initially treated without external fixation but all other patients were immobilized in long arm casts. All fractures united promptly. There were no infections, no mortality, and few complications. Although this series is small, the results are sufficiently encouraging to recommend further trial.