Incidence, Risk, and Outcome of Pedicle Screw Loosening in Degenerative Lumbar Scoliosis Patients Undergoing Long-Segment Fusion

Study Design: Retrospective study. Objective: To investigate the incidence, risk factors, and outcomes of pedicle screw loosening in degenerative lumbar scoliosis (DLS) undergoing long-segment spinal fusion surgery. Methods: One hundred and thirty DLS patients who underwent long-segment fusion surgery with at least a 12-month follow-up were studied. The incidence and risk factors of screw loosening were investigated. VAS, SRS-22, and ODI scores were obtained preoperatively and at follow-up. Results: One hundred and sixty-eight of 1784 (9.4%) screws showed evidence of loosening in 71 (54.6%) patients. Three patients required revision surgery. Screw loosening rates according to vertebral insertion level were lowest instrumented vertebra (LIV): 45.4%; uppermost instrumented vertebra (UIV):17.7%; one vertebra above the LIV: 0.5%; 2 vertebrae above the LIV: 0.4%. Multiple logistic regression analysis of possible risk factors indicated that preoperative lateral subluxation ≥8 mm (odds ratio [OR]: 2.68, 95% confidence interval [CI]: 1.16-6.20), osteopenia (OR: 5.52, 95% CI: 1.64-18.56), osteoporosis (OR: 8.19, 95% CI: 2.40-27.97), fusion to sacrum (OR: 2.55, 95% CI: 1.12-5.83), postoperative TLK greater than 10° (OR: 2.63, 95% CI: 1.14-6.04) and SVA imbalance (OR: 3.44, 95% CI: 1.17-10.14) were statistically significant. No difference was noted in preoperative, follow-up, and change of VAS, ODI, and SRS-22 scores. Conclusions: Screw loosening in DLS underwent long-segment surgery is common and tends to occur in the LIV or UIV. Lateral subluxation ≥8 mm, osteopenia, osteoporosis, fusion to the sacrum, postoperative TLK greater than 10°, and SVA imbalance were the independent influencing factors. Screw loosening can be asymptomatic, while longer-term follow-up is required.

Radiologic prognostic factors of curve progression in early degenerative lumbar scoliosis

OBJECTIVESeveral radiological parameters related to the aging spine have been reported as progression factors of early degenerative lumbar scoliosis (DLS). However, it has not been determined which factors are the most important. In this study the authors aimed to determine the risk factors associated with curve progression in early DLS.METHODSFifty-one patients with early DLS and Cobb angles of 5°–15° were investigated. In total, 7 men and 44 women (mean age 61.6 years) were observed for a mean period of 13.7 years. The subjects were divided into two groups according to Cobb angle progression (≥ 15° or < 15°) at the final follow-up, and radiological parameters were compared. The direction of scoliosis, apical vertebral level and rotational grade, lateral subluxation, disc space difference, osteophyte difference, upper and lower disc wedging angles, and relationship between the intercrest line and L5 vertebra were evaluated.RESULTSDuring the follow-up period, the mean curve progression increased from 8.8° ± 3.2° to 19.4° ± 8.9°. The Cobb angle had progressed by ≥ 15° in 17 patients (33.3%) at the final follow-up. In these patients the mean Cobb angle increased from 9.4° ± 3.4° to 28.8° ± 7.5°, and in the 34 remaining patients it increased from 8.5° ± 3.1° to 14.7° ± 4.8°. The baseline lateral subluxation, disc space difference, and upper and lower disc wedging angles significantly differed between the groups. In multivariate logistic regression analysis, only the upper and lower disc wedging angles were significantly correlated with curve progression (OR 1.55, p = 0.035, and OR 1.89, p = 0.004, respectively).CONCLUSIONSAsymmetrical degenerative change in the lower apical vertebral disc, which leads to upper and lower disc wedging angles, is the most substantial factor in predicting early DLS progression.

Therapeutic Strategy of Percutaneous Transforaminal Endoscopic Decompression for Stenosis Associated With Adult Degenerative Scoliosis

Study Design: A retrospective study. Objective: To investigate the effects of percutaneous transforaminal endoscopic decompression (PTED) for lumbar stenosis associated with adult degenerative scoliosis and to analyze the correlation between preoperative radiological parameters and postoperative surgical outcomes. Methods: Two years of retrospective data was collected from 46 patients with lumbar stenosis associated with adult degenerative scoliosis who underwent PTED. The visual analog scale (VAS), Oswestry Disability Index, and modified MacNab criteria were used to evaluate the clinical outcomes. Multiple linear regression analysis was used to analyze the correlation between radiological parameters and surgical outcomes. Results: The mean age of the 33 female and 13 male patients was 73.5 ± 8.1 years. The mean follow-up was 27.6 ± 3.5 months (range from 24 to 36). The average coronal Cobb angle was 24.5 ± 8.2°. There were better outcomes of the VAS for leg pain and Oswestry Disability Index after surgery. Based on the MacNab criteria, excellent or good outcomes were noted in 84.78% of patients. Multiple linear regression analysis showed that Cobb angle and lateral olisthy may be the predictors for low back pain. Conclusion: Transforaminal endoscopic surgery may be an effective and safe method for geriatric patients with lumbar stenosis associated with degenerative scoliosis. The predictive factors of clinical outcomes were severe Cobb angle and high degree lateral subluxation. Transforaminal endoscopic surgery may not be recommended for patients with Cobb angle larger than 30° combined with lateral subluxation.

Pathological progress and prognosis of traumatic femur head necrosis after femoral neck fracture in children and adolescent: a retrospective case series of 64 patients

Background: The pathological progression and prognosis of traumatic femur head necrosis (TFHN) after femoral neck fracture (FNF) in children and adolescent is relatively unknown and has never been specifically characterized. As we speculated, the prognosis in such population would be poor and characterized as the high risk of femoral head collapse, hip deformity and degeneration in a short term.Methods: This retrospective case series enrolled 64 children and adolescent with TFHN who treated with observational treatment from 2000.1 to 2018.1. The primary outcomes, such as the progression of femoral head collapse, hip deformity (Stulberg classification) and hip degeneration (Tönnis grade), and their prognostic factors were analysed.Results: 42 males and 22 females with a mean age of 13 years (6-16 years), were included. A total of 28 hips (44%) showed unsatisfactory outcome and Twenty-five (39%) hips collapsed progressively during a mean follow-up of 48 months (24-203 months). Finally, 38 hips (59%) experienced hip deformity, 20 of them were class IV/V. 34 hips (53%) generally progressed to osteoarthritis, 14 of them were classified as grades II/III. The location of the lesion and the presence of lateral subluxation were found to be independently related to progression of femoral head collapse; however, the presence of lateral subluxation was the only independent risk factor of severe hip deformity and degeneration.Conclusion: TFHN in children and adolescent is a rapidly progressing disease with a poor prognosis characterized by a high risk of femoral head collapse progression. If the lateral subluxation emerged, collapsed cases showed increasingly tendency towards severe hip deformity and degeneration.

MPFL GRAFT TENSIONING TO TREAT PATELLAR INSTABILITY RELATED TO PATELLA ALTA: DYNAMIC SIMULATION

Background: Medial patellofemoral ligament (MPFL) reconstruction is a popular treatment for lateral patellar instability. For knees with patella alta, however, tibial tuberosity distalization is the most common approach due to concerns about graft tensioning. A MPFL graft is tensioned intra-operatively to prevent lateral subluxation without over-constraining the patella by allowing some translation. Purpose: To analyze the effects of MPFL reconstruction on lateral tracking and cartilage pressure for knees with patella alta using dynamic simulation of knee function. Methods: Knee function was simulated with 8 multibody dynamic simulation models (RecurDyn) constructed from 3.0 T MRI scans of subjects being treated for recurrent patellar instability. The models were validated in previous studies and included ligaments, tendons, and retinacular structures represented by tension-only springs (Fig1). Four models displayed patella alta; the remaining 4 models were made to reflect patella alta by lengthening the springs. Forces were applied to simulate a dual limb squat from 0º to 90º. Motion was simulated in a pre-operative condition and for three MPFL graft tensioning techniques (1.0, 0.5, and 0 patellar quadrants of lateral translation). The maximum bisect offset index during flexion was used as a measure of patellar instability and the maximum pressures applied to patellar cartilage (lateral, medial) as measures of the risk of overloading cartilage. Statistics were used to compare the parameters with significance set at p < 0.05. Post- and pre-operative maximum bisect offset index were also correlated. Results: MPFL reconstruction with 0.5 and 0 quadrants of allowed lateral translation significantly decreased the maximum bisect offset index compared to the pre-operative condition, but not for 1.0 quadrants (Table 1). MPFL reconstruction did not significantly influence the maximum pressure applied to medial or lateral cartilage. The maximum post-operative bisect offset index was significantly correlated with the pre-operative bisect offset index for 1.0 and 0.5 quadrants of lateral translation allowed (r2 = 0.80, 0.65, and 0.48 for grafts allowing 1, 0.5 and 0 quadrants of translation, respectively). Conclusion: For knees with patella alta, the influence of MPFL reconstruction on patellar tracking varied with the allowed patellar translation during graft tensioning. None of the graft tensioning conditions significantly decreased the maximum lateral pressure or increased the medial cartilage pressure. Significance: The graft tensioning process for MPFL reconstruction typically allows some lateral patellar translation to avoid overconstraining the knee. For knees with patella alta, reducing the allowed lateral translation seems to limit maltracking without overconstraining the knee. [Table: see text][Figure: see text]

The natural history of traumatic femur head necrosis after femoral neck fracture in children and adolescent: a retrospective case series of 64 patients

Background: The natural history of traumatic femur head necrosis (TFHN) after femoral neck fracture (FNF) in children and adolescent is relatively unknown and has never been specifically characterized. As we speculated, the natural history in such population would be poor and characterized as the high risk of femoral head collapse, hip deformity and degeneration in a short term. Methods: This retrospective case series enrolled 64 children and adolescent with TFHN who treated with observational treatment from 2000.1 to 2018.1. The primary outcomes, such as the progression of femoral head collapse, hip deformity (Stulberg classification) and hip degeneration (Tönnis grade), and their prognostic factors were analysed. Results: 42 males and 22 females with a mean age of 13 years (6-16 years), were included. A total of 28 hips (44%) showed unsatisfactory outcome and Twenty-five (39%) hips collapsed progressively during a mean follow-up of 48 months (24-203 months). Finally, 38 hips (59%) experienced hip deformity, 20 of them were class IV/V. 34 hips (53%) generally progressed to osteoarthritis, 14 of them were classified as grades II/III. The location of the lesion and the presence of lateral subluxation were found to be independently related to progression of femoral head collapse; however, the presence of lateral subluxation was the only independent risk factor of severe hip deformity and degeneration. Conclusion: TFHN in children and adolescent is a rapidly progressing disease with a poor natural history characterized by a high risk of femoral head collapse progression. If the lateral subluxation emerged, collapsed cases showed increasingly tendency towards severe hip deformity and degeneration.

The Function of the Short Lateral Collateral Ligaments of the Canine Tarsus: A Cadaveric Study

ABSTRACT Information on the clinical behavior and treatment of cases with an isolated rupture of the short collateral ligaments of the canine tarsus is sparse and contradictory in the veterinary literature. Our objective was to evaluate the function of the short lateral collateral ligaments (SLCLs) of the tarsocrural joint in 90° flexion. Eight canine cadaveric limbs were tested for internal/external rotation and valgus/varus before and after transection of one or both SLCLs. In one group, the fibulocalcaneal ligament was transected first, followed by the fibulotalar. In the second group, the order of ligament transection was reversed. Angular changes between two k-wires were measured and compared. External rotation increased significantly after transection of one or both SLCLs (P = .009 and P &lt; .0005), as did varus (P = .021 and P = .001). Lateral subluxation was only possible when both SLCLs were cut. Unlike the long lateral collateral ligament, which stabilizes against deviation toward medial, both SLCLs are major stabilizers against subluxation toward lateral. This important difference must be considered in clinical patients with isolated rupture of the SLCLs.

Evaluate the Medial Muscle Strength by Kick Training between the Standing and Sitting Postures

In order to ameliorate the anterior knee pain or peripheral pain around the tibia caused by patellar lateral subluxation, we evaluated the kick training effects of standing or sitting postures in strengthening the vastus medialis obliquus (VMO) on the quadriceps femoris muscle. A total of 83 subjects (45 male; 38 female) in both sitting and standing positions performed 10° to 90° leg lift and kick training. Among the male group, the effect of the sitting posture was better than that of the standing posture, 74.31% of the former achieved the training goal. In the female group, the effect of a standing posture was better than that of a sitting posture, for which only 37.71% of the latter achieved the training purpose. However, a ratio of 84.34% in the female group showed that the strength of VMO on the quadriceps femoris muscle generated by leg kicking was greater than the strength generated by walking. While it was impossible to immediately achieve a greater effect of VMO on the quadriceps femoris muscle than vastus lateralis on the quadriceps femoris muscle, leg kicking did achieve the objective of enhancing the strength of VMO on the quadriceps femoris muscle.