Posterior Wedge Research Articles

Biomechanical evaluation of Gamma 3 nail with anti-rotation screw fixation for unstable femoral neck fractures: a biomechanical study

This study aims to evaluate the biomechanical performance of the Gamma 3 nail with an anti-rotation screw (GNS) and compare it to two established gold-standard methods for treating unstable femoral neck fractures (UFNFs). Synthetic bone models were prepared with Pauwels’ type III osteotomy and an additional posterior wedge. Three different implant configurations were tested: three cannulated crews (3CS) in an inverted triangle configuration, a dynamic hip screw with an anti-rotation screw (DHSS), and GNS. Non-destructive cyclic axial loading was applied at 7° adduction, with 1000 cycles ranging from 100 to 1000 N. Subsequently, a construct failure test was conducted using progressive axial compression, and fracture reduction loss was recorded. The average axial stiffness was 321 ± 52 N/mm for 3CS, 430 ± 71 N/mm for DHSS, and 519 ± 104 N/mm for GNS. The average ultimate failure loads were 2699.3 N for 3CS, 3427.1 N for DHSS, and 3758.9 N for GNS. GNS demonstrated significantly greater axial stiffness compared to the other two groups (P < 0.05). Both DHSS and GNS exhibited similar failure loading, which were greater than those of 3CS (P < 0.05). GNS offers the advantages of a minimally invasive and intramedullary implant with comparable stability to the DHSS system. Moreover, GNS demonstrated superior biomechanical performance compared to 3 CS configuration.

Effects of Various Foot Wedges on Thigh Muscle Activity during Squatting in Healthy Adults: A Systematic Review and Meta-Analysis

Squatting is a common movement in daily activities, athletic training, rehabilitation programs, and even in the workplace. Identifying the effects of various foot wedges on thigh muscle activity during squatting can help specialists in terms of rehabilitation, injury prevention, physical preparation, and occupational optimization. In this study, systematic literature searches in six electronic databases (Cochrane Library, PubMed, Google Scholar, Web of Science, ScienceDirect, and Scopus) were conducted up to December 2023. Fifteen studies met the inclusion criteria (total n = 269 subjects). The results showed that posterior wedges significantly increased the overall activity of thigh muscles (p &lt; 0.001, 12 studies). No significant change was observed for anterior (p = 0.730, six studies), medial (p = 0.169; three studies), and lateral wedges (p = 0.989, two studies). Compared with a non-wedge condition, the activity of the vastus medialis (p &lt; 0.001, eight studies) was significantly higher using a posterior wedge during squatting, as was the activity of the rectus femoris (p = 0.021, five studies) using the anterior wedge. It seems that thigh muscle activation is modifiable with a change in footwear design, which may be useful during sports training, rehabilitation, or daily work routines.

An Algorithm for Labia Minora Reduction Based on a Review of Anatomical, Configurational, and Individual Considerations

A variety of reduction labiaplasty techniques have been introduced to date, but no single technique will offer the optimal solution for every patient. Rather, the technique should be chosen based on anatomical, configurational, and technical considerations, as well as on patients' personal preferences regarded maintenance of the labial rim, maintenance of labial sensitivity, and prevention of iatrogenic thickening of the labium. We reviewed, defined, and assessed labial configurational variety, neurovascular supply, reduction techniques, and patient's preferences as the considerations relevant to the choice of labiaplasty technique. Based on this review, an algorithm was constructed that leads to a choice of reduction technique through five decisions to be made regarding (1) resection or (partial) retention of the labial free rim, (2) the measure of required labial width reduction, (3) labial vascular status, (4) prevention of iatrogenic labial thickening, and (5) preservation of labial sensibility. The choice of techniques includes edge trimming, central spindle form de-epithelialization or full-thickness resection, and three modifications of the wedge resection or de-epithelialization technique. These three modifications comprised a modified anterior resection or de-epithelialization combined with posterior flap transposition, a custom flask resection or de-epithelialization, and a modified posterior wedge resection or de-epithelialization combined with anterior flap transposition. Use of the five decisional steps and the inclusion of modifications of all three conventional reduction techniques offer an improved algorithm for the choice of labioplasty technique.

Poster 145: Posterior Glenoid Osteotomy with Capsulolabral Repair Restores Force in a Critical Bone Loss Biomechanical Model

Objectives:Bone loss in posterior shoulder instability is an increasingly recognized clinical phenomenon. There is no widespread consensus on the surgical treatment of posterior shoulder instability with critical posterior glenoid bone loss. Here, we study the effect of opening posterior wedge osteotomy on resistance force of soft tissue repair alone in the setting of 20% critical bone loss.Methods:Native glenoid retroversion was measured on 9 cadavers. The humerus was potted in 90 degrees of forward flexion and 30 degrees of internal rotation relative to the scapula and a posterior dislocation was performed in order to create a posterior capsulolabral injury model. The specimens were each taken through a fixed sequence of testing: (1) posteroinferior capsulolabral tear, (2) no glenoid bone loss with posteroinferior capsulolabral repair, (3) 20% posterior glenoid bone loss with posteroinferior capsulolabral repair, (4) and 20% glenoid bone loss with posterior glenoid opening wedge osteotomy and posteroinferior capsulolabral repair. The resultant peak forces with 1 centimeter of posterior translation were measured. A one-way repeated-measures analysis of variance (RM-ANOVA) was used to compare mean force values.Results:Following the initial dislocation event, all shoulder had a resultant posterior capsulolabral injury. Repairing the capsulolabral complex in the 20% posterior glenoid bone loss group did not result in a statistically significant increase in resistance force compared to the labral deficient group, p = 0.068. When 20% posterior bone loss was created, the posterior glenoid osteotomy with capsulolabral repair was significantly stronger than the posterior repair alone both with and without bone loss, p = 0.008 and p = 0.045, respectively.Conclusions:In the setting of critical posterior glenoid bone loss, an opening wedge posterior glenoid osteotomy with capsulolabral repair significantly improved resistance to posterior humeral translation compared to capsulolabral repair alone.

Posterior wedge osteotomy assisted by O-arm navigation for treating ankylosing spondylitis with thoracolumbar fractures: an early clinical evaluation.

To explore the feasibility and efficiency of posterior wedge osteotomy assisted by O-arm navigation treatment of ankylosing spondylitis (AS) patients with thoracolumbar fracture. This is a case series study. A total of 16 cases of AS accompanied by thoracolumbar fractures from January 2012 to July 2015 were retrospectively analyzed. All patients underwent "posterior wedge osteotomy assisted by O-arm navigation". The operation time, blood loss volume, preoperative and postoperative visual analogue scale (VAS), American Spinal Injury Association (ASIA) classification, and spinal imaging parameters [Cobb angle, C7 plumb line (C7PL), and jaw-brow angle] were collected and analyzed. The operative time consumption was 120-350 mins and the intra-operative blood loss volume was 200-800 mL. No obvious postoperative complications occurred in any participants. The back pain of all participants was relieved, and the neurological functions of eight participants with spinal cord injury (SCI) were recovered in varying degrees except for one patient with severe SCI. The spinal deformities of the participants were corrected to varying degrees. The fracture sites of 16 participants were all healed, and there was no loosening or detachment of internal fixation during the 6-month follow-up period. Posterior wedge osteotomy assisted by O-arm navigation was shown to be a safe and effective method to treat AS accompanied by thoracolumbar fractures. This treatment strategy can accurately decompress and reduce the fracture and significantly correct the kyphosis, with good surgical effect.

Intermediate Dynamic Compression and Decreased Posterior Tilt With Interlocked Pins in Femoral Neck Fixation in Synthetic Bone.

Fixation failure with resulting non-union is the key complication after femoral neck fixation. It can be avoided by permitting dynamic compression and reducing rotation and posterior tilt of the femoral head. To achieve this, a novel implant that features an interlocking plate with three hook-pins (The Hansson Pinloc® System) was developed from the original two hook-pins. Only an enhanced torsional fixation by the implant modification is reported. The purpose was to compare the biomechanical compressive and bending stability of the original and modified implant in femoral neck fixation. To analyze the contribution of both modified components, three individual pins were included, although not in regular use. Forty-eight synthetic femurs with mid-cervical wedge osteotomies were fixated by two pins or identical triangular pin patterns with or without the plate. Eight specimens of each group were loaded cyclically in compression with an inferior wedge to simulate stance and anteroposterior bending with a posterior wedge to imitate sitting down. The clinically relevant stability measurements were stiffness and deformation. Fissure formation defined failure. The novel implant improved bending stability by 30% increased stiffness, 44% reduced deformation, and less frequent posterior neck fissure formation (p < 0.001) while increased compressive stability was only evident with 25% reduced deformation and less frequent inferior neck fissures (p < 0.001). These impacts were mainly mediated by the third pin, while the plate prevented a lateral fissure in compression (p < 0.001). The clinical stability was improved by dynamic compression and decreased posterior tilt by implant modification.

Partial Resection of Spinous Process for the Elderly Patients with Thoraco-Lumbar Kyphosis: Technical Report.

Background and objectives: Global sagittal imbalance with lumbar hypo-lordosis can cause low back pain (LBP) during standing and/or walking. This condition has recently been well-known as one of the major causes of reduced health-related quality of life (HRQOL) in elderly populations. Decrease in disc space of anterior elements and an increase in the spinous process height of posterior elements may both contribute to the decrease in lordosis of the lumbar spine. To correct the sagittal imbalance, the mainstream option is still a highly invasive surgery, such as long-segment fusion with posterior wedge osteotomy. Therefore, we developed a treatment that is partial resection of several spinous processes of thoraco-lumbar spine (PRSP) and lumbar extension exercise to improve the flexibility of the spine as postoperative rehabilitation. Materials and Methods: Consecutively, seven patients with over 60 mm of sagittal vertical axis (SVA) underwent PRSP. The operation was performed with several small midline skin incisions under general anesthesia. After splitting the supraspinous ligaments, the cranial or caudal tip of the spinous process of several thoraco-lumbar spines was removed, and postoperative rehabilitation was followed to improve extension flexibility. Results: The average follow-up period was 13.0 months. The average blood loss and operation time were 11.4 mL and 47.4 min, respectively. The mean SVA improved from 119 to 93 mm but deteriorated in one case. The mean numerical rating scale of low back pain improved from 6.6 to 3.7 without any exacerbations. The mean Oswestry Disability Index score was improved from 32.4% to 19.1% in six cases, with one worsened case. Conclusions: We performed PRSP and lumbar extension exercise for the patients with LBP due to lumbar kyphosis. This minimally invasive treatment was considered to be effective in improving the symptoms of low back pain and HRQOL, especially of elderly patients with lumbar kyphosis.

Higher stability and more predictive fixation with the Femoral Neck System versus Hansson Pins in femoral neck fractures Pauwels II.

SummaryObjectivesTo evaluate the biomechanical performance of the Femoral Neck System (FNS) versus the Hansson Pin System (Hansson Pins) with two parallel pins in a Pauwels II femoral neck fracture model with posterior comminution.MethodsForty-degree Pauwels II femoral neck fractures AO 31-B2.1 with 15° posterior wedge were simulated in fourteen paired fresh-frozen human femora, followed by instrumentation with either FNS or Hansson Pins in pair-matched fashion. Implant positioning was quantified by measuring shortest implant distances to inferior cortex (DI) and posterior cortex (DP) on anteroposterior and axial X-rays, respectively. Biomechanical testing was performed in 20° adduction and 10° flexion with simulated iliopsoas muscle tension. Progressively increasing cyclic loading was applied until construct failure. Interfragmentary femoral head-to-shaft movements were measured with optical motion tracking.ResultsCycles to 10° varus deformation were significantly higher for FNS (23007 ​± ​5496) versus Hansson Pins (17289 ​± ​4686), P ​= ​0.027. Cycles to 10° femoral head dorsal tilting (FNS: 12765 ​± ​3425; Hansson Pins: 13357 ​± ​6104) and cycles to 10° rotation around the femoral neck axis (FNS: 24453 ​± ​5073; Hansson Pins: 20185 ​± ​11065) were comparable between the implants, P ​≥ ​0.314. For Hansson Pins, the outcomes for varus deformation and dorsal tilting correlated significantly with DI and DP, respectively (P ​≤ ​0.047), whereas these correlations were not significant for FNS (P ​≥ ​0.310).ConclusionsFrom a biomechanical perspective, by providing superior resistance against varus deformation and performing in a less sensitive way to variations in implant placement, the angular stable Femoral Neck System can be considered as a valid alternative to the Hansson Pin System for the treatment of Pauwels II femoral neck fractures.Level of evidencetherapeutic, Level V.The Translational potential of this articleThe translational potential of this article is to compare the performance of the FNS with Hansson Pins in a AO 31-B2.1 fracture model featuring a 15 posterior wedge to show the implants behavior concerning the dorsal tilting tendency.

Cervical Spondylotic Myelopathy with Ossification of Posterior Longitudinal Ligament: Which Is the Most Suitable Surgical Procedure? A Technical Note.

Introduction Anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) are widely performed to resolve anterior cervical spine compression. The main purpose of the different surgical techniques is to obtain an adequate decompression of the spinal cord and nerve roots, preserving spinal stability like in oblique corpectomy or leading to a final solid construct to achieve arthrodesis. Technical Note We describe a surgical procedure for treating cervical spondylotic myelopathy(CSM) with ossification of the posterior longitudinal ligament (OPLL) at the level of C3-C4 and C4-C5. A double level discectomy C3-C4 and C4-C5 and selective posterior wedge corpectomy of C3, C4, and C5 were performed. Two cages (Zero-P VA) at C3-C4 and C4-C5 were positioned to obtain segmental stability and arthrodesis. An extended anterior cervical canal decompression was obtained and confirmed by postsurgical CT scan. At 15 months, dynamic X-ray showed fusion, and cervical magnetic resonance imaging (MRI) showed evidence of spinal canal decompression. Conclusions Anterior cervical discectomy followed by selective wedge corpectomy appears to be a safe and effective technique for anterior spinal cord compression extending above and below the intervertebral disc space.

Biomechanical evaluation of locked plating fixation for unstable femoral neck fractures.

AimsEvaluate if treating an unstable femoral neck fracture with a locking plate and spring-loaded telescoping screw system would improve construct stability compared to gold standard treatment methods.MethodsA 31B2 Pauwels’ type III osteotomy with additional posterior wedge was cut into 30 fresh-frozen femur cadavers implanted with either: three cannulated screws in an inverted triangle configuration (CS), a sliding hip screw and anti-rotation screw (SHS), or a locking plate system with spring-loaded telescoping screws (LP). Dynamic cyclic compressive testing representative of walking with increasing weight-bearing was applied until failure was observed. Loss of fracture reduction was recorded using a high-resolution optical motion tracking system.ResultsLP constructs demonstrated the highest mean values for initial stiffness and failure load. LP and SHS constructs survived on mean over 50% more cycles and to loads 450 N higher than CS. During the early stages of cyclic loading, mean varus collapse of the femoral head was 0.5° (SD 0.8°) for LP, 0.7° (SD 0.7°) for SHS, and 1.9° (SD 2.3°) for CS (p = 0.071). At 30,000 cycles (1,050 N) mean femoral neck shortening was 1.8 mm (SD 1.9) for LP, 2.0 mm (SD 0.9) for SHS, and 3.2 mm (SD 2.5) for CS (p = 0.262). Mean leg shortening at construct failure was 4.9 mm (SD 2.7) for LP, 8.9 mm (SD 3.2) for SHS, and 7.0 mm (SD 4.3) for CS (p = 0.046).ConclusionUse of the LP system provided similar (hip screw) or better (cannulated screws) biomechanical performance as the current gold standard methods suggesting that the LP system could be a promising alternative for the treatment of unstable fractures of the femoral neck.Cite this article: Bone Joint Res 2020;9(6):314–321.

Does posterior half-wedge augmented glenoid restore version and alignment in total shoulder arthroplasty for the B2 glenoid?

IntroductionWalch type B2 has biconcave glenoid with posterior erosion, bone loss and humeral head subluxation. This leads to decreased glenohumeral contact area and increased contact pressure. During total shoulder arthroplasty(TSA), uncorrected retroversion causes eccentric loading and failure of glenoid component. It also leads to humeral head decentring with posterior rim loading, early glenoid wear and component loosening. This study aims to review anatomical restoration of glenoid version and humeral head centring in TSA with B2 glenoid using CT scans. MethodsThis is a retrospective review of TSA for glenohumeral osteoarthritis with B2 Glenoid morphology. All polyethylene posterior wedge augmented glenoid component was used. All patients underwent pre and post surgery CT Scans. Glenoid version was calculated using neoglenoid line and medial scapular border as reference point. Post-operative humeral head centering was calculated using offset of centre of rotation of humeral head with plane of scapula on axial CT-Scan. ResultsStudy had 10 patients with 11 TSA between June 2017 and July 2018. Mean age was 59(45–80)years. Mean preoperative retroversion was 16(13–23)degrees. This was corrected to a mean of 0° retroversion postoperatively. 63% had good radiological correction (0–5° retroversion). Humeral head was well centered post-operatively with mean humeral scapula alignment offset of 2.1(0.8–4.5) mm posteriorly. All cases had well-centered humeral head postoperatively with offset less than 5 mm. ConclusionsTotal shoulder replacement in B2 glenoid is technically demanding. Our radiological results show favourable outcome in terms of correction of gelenoid retroversion and eliminating posterior instability using wedge glenoid component. Level of evidenceIV.

A modified posterior wedge osteotomy with interbody fusion for the treatment of thoracolumbar kyphosis with Andersson lesions in ankylosing spondylitis: a 5-year follow-up study.

BackgroundAndersson lesions (ALs), also known as spondylodiscities, destructive vertebral lesions and spinal pseudarthrosis, usually occur in patients with ankylosing spondylitis (AS). Inflammatory and traumatic causes have been proposed to define this lesion. Different surgical approaches including anterior, posterior, and combined anterior and posterior procedure have been used to address the complications, consisting of mechanical pain, kyphotic deformity, and neurologic deficits. However, the preferred surgical procedure remains controversial. The aim of this study was to illustrate the safety, efficacy, and feasibility of a modified posterior wedge osteotomy for the ALs with kyphotic deformity in AS.MethodsFrom June 2008 to January 2013, 23 patients (18 males, 5 females) at an average age of 44.8 years (range 25–69 years) were surgically treated for thoracolumbar kyphosis with ALs in AS via a modified posterior wedge osteotomy in our department. All sagittal balance parameters were assessed by standing lateral radiography of the whole spine before surgery and during the follow-up period. Assessment of radiologic fusion at follow-up was based on the Bridwell interbody fusion grading system. Ankylosing spondylitis quality of life (ASQoL) and visual analog scale (VAS) scores were performed to evaluate improvements in daily life function and back pain pre-operatively and post-operatively. Paired t tests were used to compare clinical data change in parametric values before and after surgery and the Mann-Whitney U test was employed for non-parametric comparisons. The radiographic data change was evaluated by repeated measure analysis of variance.ResultsThe mean operative duration was 205.4 min (range 115–375 min), with an average blood loss of 488.5 mL (range 215–880 mL). Radiographical and clinical outcomes were assessed after a mean of 61.4 months of follow-up. The VAS back pain and ASQoL scores improved significantly in all patients (7.52 ± 1.31 vs. 1.70 ± 0.70, t = 18.30, P < 0.001; 13.87 ± 1.89 vs. 7.22 ± 1.24, t = 18.53, P < 0.001, respectively). The thoracolumbar kyphosis (TLK) changed from 40.03 ± 17.61° pre-operatively to 13.86 ± 6.65° post-operatively, and 28.45 ± 6.63° at final follow-up (F = 57.54, P < 0.001), the thoracic kyphosis (TK) changed from 52.30 ± 17.62° pre-operatively to 27.76 ± 6.50° post-operatively, and 28.45 ± 6.63° at final follow-up (F = 57.29, P < 0.001), and lumbar lordosis (LL) changed from −29.56 ± 9.73° pre-operatively to −20.58 ± 9.71° post-operatively, and −20.73 ± 10.27° at final follow-up (F = 42.50, P < 0.001). Mean sagittal vertical axis (SVA) was improved from 11.82 ± 4.55 cm pre-operatively to 5.12 ± 2.42 cm post-operatively, and 5.03 ± 2.29 cm at final follow-up (F = 79.36, P < 0.001). No obvious loss of correction occurred, according to the lack of significant differences in the sagittal balance parameters between post-operatively and the final follow-up in all patients (TK: 27.76 ± 6.50° vs. 28.45 ± 6.63°, TLK: 13.86 ± 6.65° vs. 14.42 ± 6.7°, LL: −20.58 ± 9.71° vs. −20.73 ± 10.27°, and SVA: 5.12 ± 2.42 cm vs. 5.03 ± 2.29 cm, all P > 0.05, respectively).ConclusionsThe modified posterior wedge osteotomy is an accepted surgical procedure for treating thoracolumbar kyphosis with ALs in AS and results in satisfactory local kyphosis correction, solid fusion, and good clinical outcomes.

Does Posterior Half-Wedge Augmented Glenoid Restore Version and Alignment in Total Shoulder Arthroplasty for the B2 Glenoid?

Abstract Introduction Walch type B2 has biconcave glenoid with posterior erosion, bone loss and humeral head subluxation. This leads to decreased glenohumeral contact area and increased contact pressure. During total shoulder arthroplasty(TSA), uncorrected retroversion causes eccentric loading and failure of glenoid component. It also leads to humeral head decentring with posterior rim loading, early glenoid wear and component loosening. This study aims to review anatomical restoration of glenoid version and humeral head centring in TSA with B2 glenoid using CT scans. Methods This is a retrospective review of TSA for glenohumeral osteoarthritis with B2 Glenoid morphology. All polyethylene posterior wedge augmented glenoid component was used. All patients underwent pre and post surgery CT Scans. Glenoid version was calculated using neoglenoid line and medial scapular border as reference point. Post-operative humeral head centering was calculated using offset of centre of rotation of humeral head with plane of scapula on axial CT-Scan. Results Study had 10 patients with 11 TSA between June 2017 and July 2018. Mean age was 59(45–80)years. Mean preoperative retroversion was 16(13–23)degrees. This was corrected to a mean of 0° retroversion postoperatively. 63% had good radiological correction (0–5° retroversion). Humeral head was well centered post-operatively with mean humeral scapula alignment offset of 2.1(0.8–4.5) mm posteriorly. All cases had well-centered humeral head postoperatively with offset less than 5 mm. Conclusions Total shoulder replacement in B2 glenoid is technically demanding. Our radiological results show favourable outcome in terms of correction of gelenoid retroversion and eliminating posterior instability using wedge glenoid component. Level of evidence IV.

1188 Manual Tissue Extraction: Approach to Vaginal Morcellation

Video Objective Vaginal morcellation is a manual tissue extraction technique used to remove large specimens following robotic, laparoscopic, or vaginal hysterectomy. The objective of this video is to present the technique and required equipment for performing vaginal morcellation following laparoscopic hysterectomy. Setting The case presented is of a 42yo G3P3 woman who presented with fibroid-related abnormal uterine bleeding and a 14-16 week size uterus, with minimal descent. Ultrasound described a multi-fibroid uterus with a normal adnexa. Recent pap smear and endometrial biopsy were normal. Following appropriate counselling, she underwent a total laparoscopic hysterectomy, bilateral salpingectomy, cystoscopy and subsequent vaginal morcellation of the uterine specimen. Interventions We demonstrate a safe and effective vaginal morcellation technique performed with bisection of the uterus, sequential anterior and posterior wedge resections and myomectomy. Conclusion Vaginal morcellation is a safe and feasible technique for manual tissue extraction in the well-selected patient. This procedure allows the surgeon to continue offering minimally invasive options to select patient populations and circumvents the need for laparotomy for specimen extraction. In recent years, there have been concerns regarding morcellation and the potential for inadvertent dissemination of malignant tissue. However, with appropriate patient selection, thorough pre-operative evaluation and careful surgical technique, the risks are low.

Extended Asymmetrical Pedicle Subtraction Osteotomy for Adult Spinal Deformity: 2-Dimensional Operative Video.

Pedicle subtraction osteotomy (PSO) is an effective technique to correct fixed sagittal malalignment. A variation of this technique, the "trans-discal" or "extended" PSO (Schwab grade IV osteotomy), involves extending the posterior wedge resection of the index vertebra to include the superior adjacent disc for radical discectomy. The posterior wedge may be resected in asymmetric fashion to correct concurrent global coronal malalignment.This video illustrates the technical nuances of an extended asymmetrical lumbar PSO for adult spinal deformity. A 62-yr-old female with multiple prior lumbar fusions presented with worsening back pain and posture. Preoperative scoliosis X-rays demonstrated severe global sagittal and coronal malalignment (sagittal vertical axis [SVA, C7-plumbline] of 13.5 cm, pelvic incidence [PI] of 60°, lumbar lordosis [LL] of 14° [in kyphosis], pelvic tilt [PT] of 61°, thoracic kyphosis [TK] of 18°, and rightward coronal shift of 9.3 cm). The patient gave informed consent to surgery and for use of her imaging for medical publication. Briefly, surgery first involved transpedicular instrumentation from T10 to S1 with bilateral iliac screw fixation, and then T11-12 and T12-L1 Smith-Petersen osteotomies were performed. Next, an extended asymmetrical L4 PSO was performed and a 12° lordotic cage (9×14×40 mm) was placed at the PSO defect. Rods were placed from T10 to iliac bilaterally, and accessory supplemental rods spanning the PSO were attached. Postoperative scoliosis X-rays demonstrated improved alignment: SVA 5.5 cm, PI 60°, LL 55°, PT 36°, TK 37°, and 3.7 cm of rightward coronal shift. The patient had uneventful recovery.

Stage-specific meniscal features predict progression of osteoarthritis of the knee: a retrospective cohort study using data from the osteoarthritis initiative

BackgroundIn the progression of osteoarthritis (OA) of the knee, a correlation between meniscal posterior segment injuries and medial meniscal extrusion has been reported, but there have been few reports on the relationship with the meniscal shape. The purpose of this study was to clarify the features of the meniscal shape involved in the progression of knee OA.MethodsData were obtained from the Osteoarthritis Initiative (OAI) database. We defined two sets of subjects. One set included 455 knees of subjects whose OA grade on the Kellgren Lawrence (KL) scale progressed in 24 months from baseline and the other set consisted of 455 knees with no progression. The OA progressed subjects were divided to three groups: the “OA change group”, KL0 and KL1 knees that progressed to KL2 and KL3; the “mild change group”, KL2 knees that progressed to KL3; and the “severe change group”, KL2 and KL3 knees that progressed to KL4. The no progression set was divided into three groups whose OA grade remained unchanged. We used magnetic resonance imaging data and manually measured seven items (longitudinal diameter [LD], anterior wedge thickness, anterior wedge width, posterior wedge width, posterior wedge thickness, anterior wedge angle, posterior wedge angle) from the sagittal slice and the extrusion from the coronal slice. These measurements were compared between knees with and without OA progression.ResultsIn the “OA change group” and “mild change group”, the anterior and posterior wedge widths and the extrusion were significantly larger, but the anterior and the posterior wedge angles were significantly smaller. In the “severe change group,” the LD and the extrusion were significantly larger. In each group, there was no uniform tendency for the correlation coefficient of the parameters evaluated.ConclusionsOur findings suggested (1) a larger meniscal LD at the baseline predicted progression of knee OA after 24 months and (2) a larger meniscal width and smaller meniscal angle predicted progression of knee OA after 24 months.

A modification and validation of quantitative morphometry classification system for osteoporotic vertebral compressive fractures in mainland Chinese.

OVCF is a manifestation of osteoporosis. To improve clinical management of osteoporosis, the quantitative morphometry (QM) system has been widely used for the early diagnosis and precise classification of OVCF in developed countries. Here, we present an mQM system and validated its use in detecting OVCF in Mainland Chinese. Using our mQM system, the pre- and post-operative values of vertebral heights were measured and evaluated in 309 Mainland Chinese who received percutaneous kyphoplasty (PKP) as OVCF treatment. Measurements and classification of fractures from the mQM system were validated by comparing to values obtained by the Genant semiquantative (SQ) method. Moreover, we evaluated the sensitivity of the mQM system by its ability to detect restoration of vertebral heights and predict cement leakage after PKP. The five classification of fractures, No deformity (ND), anterior wedge (AW), posterior wedge (PW), biconcavity (BC), and compression (CP), evaluated by the mQM method shared similar distribution characteristics compared to those obtained by the SQ method. In addition, mQM evaluation showed that the vertebra height of all fracture types showed significant restoration after PKP. The incidence of cement leakage was most common in CP (37.5%), followed by AW (31.6%), BC (26.5%), ND (23.7%), and PW (0.0%). Our mQM system is suitable for classification of fractures, detection of vertebral height restoration, and correlation of cement leakage after PKP in Mainland Chinese population.

Clinical and Radiographic Results After Posterior Wedge Osteotomy for Thoracolumbar Kyphosis Secondary to Ankylosing Spondylitis: Comparison of Long and Short Segment

To compare the efficacy of long and short segment instrumentation after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis caused by ankylosing spondylitis (AS). Sixty-four consecutive AS patients were analyzed and divided into groups according to length of instrumentation. We defined short segment instrumentation (SSI) as construct length <7 levels (≤3 levels above and below the osteotomy) (n= 17). By contrast, long segment instrumentation (LSI) was defined as construct length ≥7 levels (≥4 levels above and ≥3 levels below the osteotomy) (n= 47). Both groups were matched cohorts. Radiographs were analyzed for correction, ossification, and complications. Correction loss in global kyphosis (GK) and lumbar lordosis (LL) of the LSI group was slightly higher than that of SSI group. Notably, a significantly higher modified Stokes Ankylosing Spondylitis Spinal Score (mSASSS) was noted in the SSI group. Pearson correlation analysis demonstrated that thoracic and lumbar spine mSASSS were significantly associated with correction loss in GK and LL, respectively. Two cases of proximal junctional kyphosis and 1 case of rod fracture occurred in the LSI group. Both approaches were able to maintain sustained surgical outcomes. Short segment instrumentation is recommended for AS patients with bridging syndesmophytes. Long constructs are better indicated for patients without fully ossified anterior longitudinal ligaments. Nevertheless, extension of the length of instrumentation might not prevent complications such as proximal junctional kyphosis or rod fracture in patients without fully ossified vertebrae.

The effect of distal femoral extension osteotomy on muscle lengths after surgery.

PurposeThe distal femoral extension osteotomy (DFEO) is often used in the treatment of crouch gait to help compensate for knee flexion contractures. The effects of DFEO on skeletal and muscle lengths are incompletely understood, but are important to consider in planning concomitant surgeries such as patellar tendon advancement (PTA). Therefore, the purpose of this study was to quantify the changes in femur, quadriceps, and hamstring lengths with DFEO, and to determine the sensitivity to surgical factors such as wedge location and magnitude.MethodsA musculoskeletal model with six degrees of freedom tibiofemoral and patellofemoral joints was used for analysis. A wedge was removed from the distal femur and the remaining bone segments were plated together to simulate the DFEO. After simulating the knee’s post-operative equilibrium, the surgically-induced changes in muscle and bone lengths were analysed.ResultsRelative to the pre-operative state, DFEO stretches the hamstrings while shortening the femur and quadriceps. A more posterior wedge apex location (i.e. creation of a cuneiform wedge) diminished the stretch of the hamstrings, but induced greater shortening of the femur and quadriceps. More proximal wedge locations necessitated greater translation of the distal fragment to maintain the knee joint axis.ConclusionReduced quadriceps length after DFEO shown in this study is consistent with the need for simultaneous PTA. The induced hamstring stretch also may represent a potential mechanism for post-operative nerve palsies. Overall, the numerical results provide a firmer basis for planning the specifics of DFEO such that desired muscle lengths and joint alignment are achieved.

The patterns of loss of correction after posterior wedge osteotomy in ankylosing spondylitis-related thoracolumbar kyphosis: a minimum of five-year follow-up

BackgroundShort-term studies have demonstrated good surgical outcomes after pedicle subtraction osteotomy (PSO) in ankylosing spondylitis (AS) patients, but there is a paucity of literature focused on middle-term results, especially regarding patterns of loss of correction. The objective of this study is to assess the durability of surgical outcomes and the patterns of loss of correction in thoracolumbar kyphosis secondary to AS following lumbar PSO with over 5-year follow-up.MethodsWe performed a retrospective review of 155 consecutive AS patients undergoing lumbar PSO from January 2001 to December 2011. Twenty-four patients were included with an average follow-up of 6.9 years (range, 5–15 years). Radiographical evaluations included global kyphosis (GK), lumbar lordosis (LL), sagittal vertical axis, spinal-sacral angle, kyphosis of proximal non-fused segments (KPNS), angle of fused segments (AFS), osteotomized vertebra angle (OVA), distal intervertebral disc wedging (DIDW) and proximal junctional angle. Meanwhile, clinical outcomes were assessed by the Oswestry disability index (ODI) and Numerical rating scale (NRS).ResultsThe average correction per PSO segment was 34.9°. Significant improvement in sagittal parameters were found postoperatively, and no obvious deterioration was noticed during the follow-up. Mild loss of correction in GK (2.82°) and LL (3.77°) were observed at the final follow-up (P < 0.05). The KPNS and DIDW increased from 26° and −5.0° postoperatively to 30° and −2.2° at the final follow-up (P < 0.05), respectively. In contrast, no significant diminishment was identified in OVA and AFS (P > 0.05). The ODI and NRS improved significantly from 20.6 and 6.6 preoperatively to 5.9 and 2.3 at the final follow-up (P < 0.05).ConclusionsPSO is an effective procedure for treating AS-related thoracolumbar kyphosis and can maintain sustained surgical outcomes during the middle-term follow-up. The loss of correction was mainly attributable to non-instrumented segments without fully ossified bridging syndesmophyte in the thoracolumbar region instead of instrumented levels.