Long-term changes in bone mineral density following adolescent idiopathic scoliosis surgery: a minimum 34-year follow-up.

PURPOSE: To investigate longitudinal changes in bone mineral density (BMD) in middle-aged female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS). METHODS: The study subjects were 229 female patients who were diagnosed with AIS and underwent spinal fusion between 1968 and 1988. A two-step survey study was conducted on 19 female AIS patients. BMD, Z-scores, T-scores, and the prevalence of osteoporosis and osteopenia were compared between the initial (2014-2016) and second (2022) surveys. Correlations between the annual changes in Z-scores and T-scores with radiographic parameters, body mass index (BMI), and the number of remaining mobile discs were analyzed. RESULTS: BMD decreased significantly from the initial (0.802 ± 0.120 g/cm2) to the second survey (0.631 ± 0.101 g/cm2; p < 0.001). Z-scores decreased from 0.12 ± 1.09 to - 0.14 ± 1.04, while T-scores decreased significantly from - 0.70 ± 1.07 to - 1.77 ± 1.11 (p < 0.001). The prevalence of osteopenia and osteoporosis increased significantly from 36.8% to 89.5% (p = 0.002), but the increase in osteoporosis alone was not statistically significant (5.3% to 26.3%; p = 0.180). Moderate negative correlations were found between annual changes in Z-scores and both main thoracic (MT) curve (r = - 0.539; p = 0.017) and lumbar curve (r = - 0.410; p = 0.081). The annual change in T-scores showed a moderate negative correlation with the MT curve (r = - 0.411; p = 0.081). CONCLUSION: Significant reductions in BMD and an increased prevalence of osteopenia and osteoporosis were observed in middle-aged female AIS patients who had undergone spinal fusion. The decline in Z-scores in patients with AIS suggested that there was an accelerated loss of BMD compared with the general population. Larger residual curves could pose an added osteoporosis risk. Further research is needed to understand if the onset of osteoporosis in AIS patients is attributable to the condition itself or the surgical intervention.

Frozen vein wrapping for chronic nerve constriction injury reduces sciatic nerve allodynia in a rat model.

BACKGROUND: Autologous vein wrapping (VW) is used in the treatment of recurrent chronic constriction neuropathy and traumatic peripheral nerve injury. However, use of autologous veins is limited by the inability to obtain longer veins of sufficient length for larger sites. Frozen allograft tissue has several advantages, including its availability for large grafts, avoidance of donor-site morbidity, and shorter operation time. Here, we investigated the effect of frozen vein wrapping (FVW) in Wistar rats as a model of sciatic nerve injury. RESULTS: The rats were grouped by treatment as (i) untreated after chronic constriction injury surgery (CCI; control group), (ii) treated with vein wrapping using freshly isolated vein (VW), and (iii) treated with vein wrapping using frozen vein (FVW). Mechanical allodynia was assessed with von Frey filaments on postoperative days (PODs) 1, 3, 5, 7, and 14. Gene expression of HO-1 was evaluated by quantitative polymerase chain reaction (qPCR). The response of heme oxygenase-1 gene, Hmox-1, expression to VW and FVW was assessed by RT-PCR. Both VW and FVW significantly increased withdrawal threshold levels compared to the untreated control group on POD 1, 3, and 5. Both VW and FVW also showed increased HO-1 expression compared to the CCI group. CONCLUSIONS: FVW increased the withdrawal threshold similar to VW in a rat CCI model for short periods. Frozen vein wrapping using vein allograft without donor site morbidity may be an alternative therapeutic option.

Intra-articular injection of monoiodoacetate induces diverse hip osteoarthritis in rats, depending on its dose.

BACKGROUND: Monoiodoacetate (MIA)-induced arthritis models are used widely in osteoarthritis (OA) research to develop effective conservative treatments for hip OA, as an alternative to joint replacement surgery. In joint OA models, such as the MIA-induced knee OA model, various doses of MIA are utilized, depending on the purpose of the research. So far, only 2 mg of MIA has been used for MIA-induced hip OA research. We hypothesized that the amount of MIA should be adjusted according to the osteoarthritis model under investigation. We performed radiographic and histological evaluations in rats for hip OA models induced by different doses of MIA. METHODS: One hundred and eighty right hips of six-week-old, male Sprague-Dawley rats (n = 30 rats per group) were treated with either a single intra-articular injection of various doses of MIA (0.25, 0.5, 1.0, 2.0, and 4.0 mg) dissolved in 25 µl of sterile saline (MIA group), or with 25 µl of sterile saline alone (Sham group). Radiographic and histological evaluations of the hip joint were performed at one, two, four, eight, and 12 weeks after administration (n = 6 rats per group per time point). RESULTS: OA changes progressed from 1 week after administration in the 1.0-mg, 2.0-mg, and 4.0-mg MIA groups. The degree of OA changes increased as the dose of MIA increased. The 0.25-mg and 0.5-mg MIA groups presented fewer OA changes than the 2.0-mg and 4.0-mg MIA groups during the entire study period (up to 12 weeks). The administration of 0.25 mg and 0.5 mg of MIA-induced both radiographic and histological OA changes in a time-dependent manner, whereas more than 2 mg of MIA provoked end-stage OA at 8 weeks after injection. Absolute, dose-dependent histopathological OA changes were observed 4 weeks after MIA administration. CONCLUSIONS: Intra-articular MIA injection to the hip joints of rats induced diverse OA changes dose-dependently. Research for developing novel conservative treatments for hip OA and intractable pain should consider the pathological condition when determining the dose of MIA to be employed.

Analgesic effects and arthritic changes following intra-articular injection of diclofenac etalhyaluronate in a rat knee osteoarthritis model.

BACKGROUND: Diclofenac etalhyaluronate (DF-HA) is a recently developed analgesic conjugate of diclofenac and hyaluronic acid that has analgesic and anti-inflammatory effects on acute arthritis. In this study, we investigated its analgesic effect on osteoarthritis, using a rat model of monoiodoacetate (MIA). METHODS: We injected MIA into the right knees of eight 6-weeks-old male Sprague-Dawley rats. Four weeks later, rats were randomly injected with DF-HA or vehicle into the right knee. Seven weeks after the MIA injection, fluorogold (FG) and sterile saline were injected into the right knees of all the rats. We assessed hyperalgesia with weekly von Frey tests for 8 weeks after MIA administration. We took the right knee computed tomography (CT) as radiographical evaluation every 2 weeks. All rats were sacrificed 8 weeks after administration of MIA for histological evaluation of the right knee and immunohistochemical evaluation of the DRG and spinal cord. We also evaluated the number of FG-labeled calcitonin gene-related peptide (CGRP)-immunoreactive(ir) neurons in the dorsal root ganglion (DRG) and ionized calcium-binding adapter molecule 1 (Iba1)-ir microglia in the spinal cord. RESULTS: Administration of DF-HA significantly improved pain sensitivity and reduced CGRP and Iba1 expression in the DRG and spinal cord, respectively. However, computed tomography and histological evaluation of the right knee showed similar levels of joint deformity, despite DF-HA administration. CONCLUSION: DF-HA exerted analgesic effects on osteoarthritic pain, but did not affect joint deformity.

Guidelines for cadaver dissection in education and research of clinical medicine (The Japan Surgical Society and The Japanese Association of Anatomists).

This article translates the guidelines for cadaver surgical training (CST) published in 2012 by Japan Surgical Society (JSS) and Japanese Association of Anatomists from Japanese to English. These guidelines are based on Japanese laws and enable the usage of donated cadavers for CST and clinical research. The following are the conditions to implement the activities outlined in the guidelines. The aim is to improve medicine and to contribute to social welfare. Activities should only be carried out at medical or dental universities under the centralized control by the department of anatomy under the regulation of Japanese law. Upon the usage of cadavers, registered donors must provide a written informed-consent for their body to be used for CST and other activities of clinical medicine. Commercial use of cadavers and profit-based CST is strongly prohibited. Moreover, all the cadaver-related activities except for the commercial-based ones require the approval of the University's Institutional Review Board (IRB) before implementation. The expert committee organized at each university for the implementation of CST should summarize the implementation of the program and report the details of the training program, operating costs, and conflicts of interest to the CST Promotion Committee of JSS.

The Effect of an Additional Core Suture During Pulvertaft Tendon Repair: A Fresh-Frozen Cadaver Study.

PURPOSE: Pulvertaft tendon repair is a strong suture technique; however, proper tendon tension is impaired by repair site elongation. Therefore, methods to reduce postoperative elongation are warranted. This study aimed to determine the effects of additional core sutures during Pulvertaft tendon repair on repair site elongation and rupture strength. METHODS: A total of 48 finger extensor tendons were harvested from fresh-frozen cadavers, and tendons with similar diameters were paired. The 24 pairs of tendons were divided into the following 4 groups: group I, 3 interlaced weaves only; group II, 3 interlaced weaves and 2 core suture strands with 4-0 nylon; group III, 3 interlaced weaves and 2 core suture strands with 4-0 FiberWire; and group IV, 4 interlaced weaves only. Each sutured tendon was placed in a Universal Testing Machine, and repair site elongation after repeated traction loads and rupture strength were measured. RESULTS: The mean elongation values were 2.74 ± 0.84 mm, 1.80 ± 0.16 mm, 1.60 ± 0.18 mm, and 1.92 ± 0.18 mm for groups I, II, III, and IV, respectively. The elongation values were significantly lower in groups II, III, and IV than in group I. The mean rupture strengths were 64.9 ± 16.0 N, 94.8 ± 17.2 N, 110.9 ± 21.3 N, and 104.9 ± 17.5 N for groups I, II, III, and IV, respectively. Rupture strengths were significantly higher for groups III and IV than for group I. CONCLUSIONS: After adding core sutures during Pulvertaft tendon repair, the elongation amount decreased, and the rupture strength improved. CLINICAL RELEVANCE: The study showed the effect of additional core sutures during Pulvertaft tendon repair, suggesting that it could be useful in reducing postoperative tendon elongation when extensor tendon transfers are performed.

Recovery of Forearm Bone Strength After Plate Removal: A Finite Element Analysis Study.

PURPOSE: The purpose of this study was to estimate the bone strength after plate removal over time and to investigate the progression of bone strength recovery. METHODS: A consecutive series of 31 patients was investigated to evaluate bone strength before and after forearm plate removal. Patients who were included underwent plate fixation for forearm diaphyseal fractures and were scheduled for plate removal. Computed tomography (CT) scans of the entire length of the bilateral forearms were taken before plate removal and at 1, 3, and 6 months after surgery. Patient-specific CT-based finite element analysis was used to predict the forearm bone fracture strength against an axial load (N), defined as the bone strength. Bone strength was estimated by patient-specific CT-based finite element analysis at each time point. RESULTS: The mean age of the patients was 40.4 years. The mean time between plate fixation and removal was 27.5 months. Bone strength before the removal was estimated as reduced to 47% of that of the uninjured side. This was constant regardless of age group, involvement of the radius or ulna, Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification, open fracture, or type of plate. Bone strength at 1, 3, and 6 months after removal was estimated to be 66%, 85%, and 97%, respectively. The bone strength of the distal ulna was weaker than that at the other sites in the forearm and showed delayed recovery. CONCLUSIONS: Bone strength after plate removal showed recovery within 3-6 months and was fully recovered by 6 months. The degree of recovery of bone atrophy varies from site to site, and patients should be careful about refracture after removal. CLINICAL RELEVANCE: Clinicians should be aware that bone strength may not be sufficiently restored even 6 months after plate removal of forearm fractures.

Biomechanical assessment of the first dorsal compartment of the wrist: A fresh cadaver study with relevance to de Quervain's disease.

Resistance of de Quervain's disease to conservative treatment has been associated with an intertendinous septum in the first compartment. This study aimed to investigate the relationship between intertendinous septum's presence or absence, internal pressure and wrist positon in the first compartment. Fourteen arms were obtained from seven fresh frozen cadavers. A pressure sensor was inserted into the first compartment; if a septum was present, the pressure sensor was inserted into the abductor pollicis longus (APL) side and the extensor pollicis brevis (EPB) side, respectively. Three wrist positions were also tested: neutral, 45° flexion, and 45° extension. Intertendinous septa were present in seven wrists. The average pressure change in the first compartment measured on the EPB side of a present septum was significantly greater than that measured on the APL side of a present septum or where no septum existed: no septum = 54.6 ± 48.3 kPa; septum, EPB = 81.7 ± 76.5 kPa; and septum, APL = 32.8 ± 37.4 kPa. The average pressure change was also significantly greater in the flexion wrist position relative to the neutral and extension positions: neutral = 36.3 ± 58.0 kPa; 45° flexion = 79.5 ± 65.9 kPa; and 45° extension = 50.4 ± 42.6 kPa. Clear relationships existed between (1) the presence of a septum and increased internal pressure on the EPB side in the first compartment and (2) increased internal pressure with the wrist at 45° flexion compared with the neutral and extension position.

Evaluation of anterior oblique ligament tension at the elbow joint angle-a cadaver study.

BACKGROUND: The ulnar collateral ligament complex, particularly the anterior oblique ligament (AOL), is mainly a static stabilizer controlling valgus. Various studies have been conducted on the kinematics of elbow joints after ligament cutting; however, no biomechanical studies have measured the tension applied to the ligament. Finite element modeling (FEM) is a very useful tool for biomechanical evaluation of the elbow. However, an accurate FEM of elbow joints cannot be developed without information on the potential tension of ligaments applied during the flexion and extension of elbow joints. We believe that FEM of the elbow joint could be obtained by measuring the material properties and potential tension of the ligament applied during the flexion and extension of the elbow joint. This study aimed to measure the potential tension and material properties of the ligament during the flexion and extension of the elbow, by identifying the relation between ligament length and tension using mechanical testing. METHODS: We included 10 elbows harvested from 7 fresh-frozen cadavers. The average age of the cadavers was 83.7 ± 5.65 years, and the samples included 8 elbows from 6 male cadavers and 2 elbows from 1 female cadaver. We measured the ligament length at each elbow angle by changing the elbow joint from 0° to 120° in 15° intervals. Thereafter, we extracted the AOL and divided into an anterior band (AB) and a posterior band (PB) and performed a mechanical test to calculate ligament stress. RESULTS: The ligament length of the AB gradually decreased as the flexion angle increased. Conversely, the ligament length of the PB gradually increased as the flexion angle increased. AB and PB lengths were approximately the same between 60° and 75°. The average ligament tension and stress of the AB gradually increased with elbow extension. In contrast, the average ligament tension and stress of the PB gradually increased with elbow flexion. The tension and stress of the AB and PB were balanced around the elbow joint at 60°. CONCLUSION: The AB was tenser on elbow extension, and the PB was tenser following elbow flexion. Also, the angle at which the AOL stress was equalized was 60°, suggesting that ∼60° is the angle at which the AOL is unlikely to be damaged.

Anatomical course of the lateral femoral cutaneous nerve with special reference to the direct anterior approach to total hip arthroplasty.

Objectives: To document the anatomical variation of the lateral femoral cutaneous nerve (LFCN) at the proximal aspect of the thigh and to determine its susceptibility to injury during total hip arthroplasty via a direct anterior approach (DAA).Methods: We obtained 64 thighs from formalin-preserved cadavers of 45 Japanese individuals. LFCN was identified at the level of the inguinal ligament. All nerve branches of the LFCN were carefully traced distally in the subcutaneous tissue. The branching pattern and distribution at the proximal aspect of the thigh were described. A safe zone to avoid LFCN injury in DAA was estimated for the skin incision.Results: The branching pattern of LFCN was highly varied. There were 37% of the anterior type, characterized by a thicker anterior branch, which coursed along the medial border of the tensor fascia lata (TFL) muscle with thinner branches. There were 63% of the posterior type, characterized by posterior branches thicker than or equal to the anterior branch. In 27 of 64 thighs (42%), the LFCN crossed the skin incision along the midline of the TFL muscle.Conclusion: LFCN showed anatomical variation of anterior and posterior branches and 42% were in danger of injury during DAA.

Diffusion tensor imaging of the sciatic and femoral nerves in unilateral osteoarthritis of the hip and osteonecrosis of femoral head: Comparison of the affected and normal sides.

Objective: The aim was to compare the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the sciatic and femoral nerves in patients with unilateral osteoarthritis of the hip (OA) and osteonecrosis of the femoral head (ONFH) using diffusion tensor imaging (DTI) and to investigate the mechanism of hip pain. Methods: Forty-four patients (22 OA and 22 ONFH) underwent DTI of the sciatic and femoral nerves at the level of the hip joint and the S1 roots to visualize the tractography and quantify the FA and ADC values. Results: The tractography of the femoral and the sciatic nerves on the affected side with OA and ONFH were similar to those on the normal side. The mean FA values of the sciatic and femoral nerves, and the S1 roots were 0.542, 0.551, and 0.316 with OA, 0.568, 0.560, and 0.318 with ONFH on the affected side, and 0.559, 0.560, and 0.315 on the normal side, respectively, and did not show significant differences. The FA values of the sciatic nerve on the affected side with OA decreased with longer pain duration. Conclusion: The FA and ADC values of the sciatic and femoral nerves in patients with unilateral OA and ONFH showed no significant differences between the affected and normal sides.

Anatomical Features of the Descending Genicular Artery to Facilitate Surgical Exposure for the Subvastus Approach-A Cadaveric Study.

BACKGROUND: The purpose of this cadaveric study was to clarify the proximal limit for the subvastus approach (SVA) in total knee arthroplasty to decrease potential vascular injury. METHODS: Seventy embalmed knees underwent a modified SVA using a 14-cm oblique medial incision. Anatomical features of the descending genicular artery (DGA) were investigated with regard to variation, distance of the vessels from surgical landmarks, and sex differences. RESULTS: The DGA was identified in 62 knees (89%), while it was absent in 8 knees (11%); in the latter, the articular, saphenous, and muscular branches arose separately from the femoral artery. The mean distances from the tibial tuberosity and medial joint line to the origin of the DGA were 15.5 ± 1.6 cm and 12.6 ± 1.6 cm, respectively. Both distances were significantly longer in males than in females (P < .01, respectively). A strong positive correlation was found between the distance from the tibial tuberosity to the origin of the DGA and the distance from the medial joint line to the origin of the DGA (Spearman's correlation coefficient, R2 = 0.72, P < .01). A weak positive correlation was found between the distance from the tibial tuberosity to the origin of the DGA and lower leg length (R2 = 0.13, P < .01). No vascular injuries were observed in this surgical exposure. CONCLUSION: The DGA showed several variations and was absent 11% of the time. An oblique medial incision within 14 cm from the tibial tuberosity followed by arthrotomy is considered a safe zone for the SVA.

Variant course of extensor pollicis brevis tendon in the third extensor compartment.

INTRODUCTION: According to the anatomical literature, the extensor pollicis brevis (EPB) tendon passes through the first compartment and enters the base of the proximal phalanx of the thumb. There have been a few reports on the different types of supernumerary EPB tendons; however, an unusual course of the EPB tendon is extremely rare. MATERIALS AND METHODS: During routine cadaveric dissection in the Department of Gross Anatomy, we detected an variant EPB muscle in a 96-year-old fresh female cadaver. RESULTS: The EPB muscle originated from the posterior surface of the radius and interosseous membrane. However, the EPB tendon passed through the third compartment instead of the first compartment. It ran parallel to the extensor pollicis longus (EPL) tendon and entered the base of the thumb proximal phalanx. The EPL tendon was attached to the base of the first distal phalanx, as normally observed. Both EPB and EPL muscles were innervated by the posterior interosseous nerve. CONCLUSIONS: We report a case of a variant course of the EPB tendon appearing in the third extensor compartment of the wrist with the EPL tendon. The knowledge of this anatomic variation will be helpful for accurate diagnosis and surgical planning.

Ultrasonography could be used to predict extended insertion of the EPB tendon noninvasively.

INTRODUCTION: An abnormal distal insertion of the extensor pollicis brevis (EPB) tendon into the thumb interphalangeal joint (IP) has been observed in refractory cases of de Quervain's disease. This is associated with the extensor being wider at the midpoint of the proximal phalanx; however, there is no method to noninvasively measure this. This study evaluated the accuracy of measuring the extensor width using ultrasonography, to establish a noninvasive method for predicting an EPB extending the IP insertion. MATERIALS AND METHODS: Of 23 arms from 12 fresh frozen cadavers, the extensor tendon width at the midpoint of the proximal phalanx was measured using ultrasonography and directly at dissection. The association between these values was evaluated using correlation analysis. A cut-off value of extensor tendon width was obtained using receiver operating characteristic analysis. RESULTS: A strong correlation was observed between the ultrasonography and the measured values. The EPB tendons were normal in 13 arms (57%) and extended in 10 (43%), with a significant difference between these groups in the mean width of the extensor tendon (6.8 ± 1.1 vs. 8.4 ± 1.0 mm). A cut-off extensor tendon width of 8.0 mm yielded an EPB extending the IP. CONCLUSION: An EPB extending the IP tendon can be predicted by measuring the extensor tendon width at the midpoint of the proximal phalanx using ultrasonography. The cut-off tendon width value of ≥ 8.0 mm may be useful for assessments prior to surgery and for conservative care.

Direct anterior approach for total hip arthroplasty with a novel mobile traction table -a prospective cohort study.

BACKGROUND: The purpose of this prospective cohort study was to clarify the safety and efficacy of total hip arthroplasty via the direct anterior approach in the supine position with a novel mobile traction table. METHODS: The first experience of consecutive surgeries by a single surgeon using the direct anterior approach with a traction table is described with a two-year follow-up period. Of 121 patients, 100 patients without previous hip surgeries, severe deformity, or cemented implants were divided into two groups comprising the first 50 patients and the second 50 patients. RESULTS: The implant survival rate was 99% at the two-year follow-up. Revision surgery was required for periprosthetic femoral fracture in one patient. The complication rate possibly related to the traction table was 5% (5 patients): three anterior dislocations, one periprosthetic femoral fracture, and one intraoperative perforation caused by femoral rasping. The complication rate tended to decrease in the second group compared to the first group (4% versus 6%). Mean surgical time (72.0 minutes versus 82.5 min, p = 0.027), rate of allogeneic blood transfusion (2% versus 24%, p = 0.001), and cup alignment in the safe zone (100% versus 88%, p = 0.027) were significantly improved in the second group compared to the first group. CONCLUSION: The direct anterior approach with a novel mobile traction table showed a positive learning curve for surgical time, rate of allogeneic blood transfusion, and cup alignment in the safe zone.

Prediction of fracture load and stiffness of the proximal femur by CT-based specimen specific finite element analysis: cadaveric validation study.

BACKGROUND: Finite element analysis (FEA) of the proximal femur has been previously validated with large mesh size, but these were insufficient to simulate the model with small implants in recent studies. This study aimed to validate the proximal femoral computed tomography (CT)-based specimen-specific FEA model with smaller mesh size using fresh frozen cadavers. METHODS: Twenty proximal femora from 10 cadavers (mean age, 87.1 years) were examined. CT was performed on all specimens with a calibration phantom. Nonlinear FEA prediction with stance configuration was performed using Mechanical Finder (mesh,1.5 mm tetrahedral elements; shell thickness, 0.2 mm; Poisson's coefficient, 0.3), in comparison with mechanical testing. Force was applied at a fixed vertical displacement rate, and the magnitude of the applied load and displacement were continuously recorded. The fracture load and stiffness were calculated from force-displacement curve, and the correlation between mechanical testing and FEA prediction was examined. RESULTS: A pilot study with one femur revealed that the equations proposed by Keller for vertebra were the most reproducible for calculating Young's modulus and the yield stress of elements of the proximal femur. There was a good linear correlation between fracture loads of mechanical testing and FEA prediction (R2 = 0.6187) and between the stiffness of mechanical testing and FEA prediction (R2 = 0.5499). There was a good linear correlation between fracture load and stiffness (R2 = 0.6345) in mechanical testing and an excellent correlation between these (R2 = 0.9240) in FEA prediction. CONCLUSIONS: CT-based specimen-specific FEA model of the proximal femur with small element size was validated using fresh frozen cadavers. The equations proposed by Keller for vertebra were found to be the most reproducible for the proximal femur in elderly people.

Evaluation of Bone Atrophy After Treatment of Forearm Fracture Using Nonlinear Finite Element Analysis: A Comparative Study of Locking Plates and Conventional Plates.

PURPOSE: Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment. METHODS: In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis. RESULTS: Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb-contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength. CONCLUSIONS: This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Inflammatory pain-related traits of sensory DRG neurons innervating the hip joints.

BACKGROUND: Hip pain is transmitted to the dorsal horn of the spinal cord via the dorsal root ganglion (DRG), which contains two types of neurons with differential sensitivity to neurotrophic factors. If either type predominantly innervates the hip joint, it may represent a good target for hip joint pain treatment. METHODS: Inflammation was induced in the left hip joint of rats (n = 10) by using complete Freund's adjuvant. Fluoro-Gold (FG) was applied to the hip joint after 7 days, and T12-L6 DRGs were double-stained for calcitonin gene-related peptide (CGRP) and isolection-IB4 1 week later. RESULTS: FG-labeled neurons in the control group were distributed throughout the left DRG from T13 to L5, primarily in L2 to L4, and CGRP-positive neurons were significantly more frequent than IB4-binding neurons. In the inflammatory group, FG-labeled neurons were similarly distributed, primarily at L3 and L4, and CGRP-positive neurons were significantly more frequent than IB4-binding neurons. The percentage of CGRP-positive neurons was significantly greater in the inflammatory group (P < 0.05). CONCLUSIONS: Most small neurons innervating the hip joint express CGRP. Furthermore, hip joint inflammation caused an increase in CGRP-positive neurons, but not in IB4-binding neurons. Our results suggest that CGRP-expressing nerve growth factor-dependent neurons are primarily responsible for hip joint pain and may represent therapeutic targets.