Aims. The presence of facet tropism has been correlated with an elevated susceptibility to lumbar disc pathology. Our objective was to evaluate the impact of facet tropism on chronic lumbosacral discogenic pain through the analysis of clinical data and finite element modelling (FEM). Methods. Retrospective analysis was conducted on clinical data, with a specific focus on the spinal units displaying facet tropism, utilizing FEM analysis for motion simulation. We studied 318 intervertebral levels in 156 patients who had undergone provocation discography. Significant predictors of clinical findings were identified by univariate and multivariate analyses. Loading conditions were applied in FEM simulations to mimic biomechanical effects on intervertebral discs, focusing on maximal displacement and intradiscal pressures, gauged through alterations in disc morphology and physical stress. Results. A total of 144 discs were categorized as ‘positive’ and 174 discs as ‘negative’ by the results of provocation discography. The presence of defined facet tropism (OR 3.451, 95% CI 1.944 to 6.126) and higher Adams classification (OR 2.172, 95% CI 1.523 to 3.097) were important predictive parameters for discography-‘positive’ discs. FEM simulations showcased uneven stress distribution and significant disc displacement in tropism-affected discs, where loading exacerbated stress on facets with greater angles. During varied positions, notably increased stress and displacement were observed in discs with tropism compared to those with normal facet structure. Conclusion. Our findings indicate that facet tropism can contribute to disc herniation and changes in intradiscal pressure, potentially exacerbating disc degeneration due to altered force distribution and increased mechanical stress. Cite this article: Bone Joint Res 2024;13(9):452–461

Cervical spine facet tropism (CFT) defined as the facets’ joints angles difference between right and left sides of more than 7 degrees. This study aims to investigate the relationship between cervical sagittal alignment parameters and cervical spine facets’ tropism. A retrospective cross-sectional study carried out in a tertiary center where cervical spine magnetic resonance imaging (MRI) radiographs of patients in orthopedics/spine clincs were included. They had no history of spine fractures. Images’ reports were reviewed to exclude those with tumors in the c-spine. A total of 96 patients was included with 63% of them were females. The mean of age was 45.53± 12.82. C2-C7 cobb's angle (CA) and C2-C7 sagittal vertical axis (SVA) means were −2.85±10.68 and 1.51± 0.79, respectively. Facet tropism was found in 98% of the sample in at least one level on either axial or sagittal plane. Axial C 2–3 CFT and sagittal C4-5 were correlated with CA (r=0.246, P 0.043, r= −278, P 0.022), respectively. In addition, C2-C7 sagittal vertical axis (SVA) was moderately correlated with axial c2-3 FT (r= −0.330, P 0.006) Also, several significant correlations were detected in our model Cervical vertebral slopes and CFT at the related level. Nonetheless, high BMI was associated with multi-level and multiplane CFT with higher odd's ratios at the lower levels. This study shows that CFT at higher levels is correlated with increasing CA and decreasing SVA and at lower levels with decreasing CA. Obesity is a risk factor for CFT

Objectives. Understanding lumbar facet joint involvement and biomechanical changes post spinal fusion is limited. This study aimed to establish an in vitro model assessing mechanical effects of fusion on human lumbar facet joints, employing synchronized motion, pressure, and stiffness analysis. Methods and Results. Seven human lumbar spinal units (age 54 to 92, ethics 15/YH/0096) underwent fusion via a partial nucleotomy model mimicking a lateral cage approach with PMMA cement injection. Mechanical testing pre and post-fusion included measuring compressive displacement and load, local motion capture, and pressure mapping at the facet joints. pQCT imaging (82 microns isotropic) was carried out at each stage to assess the integrity of the vertebral endplates and quantify the amount of cement injected. Before fusion, relative facet joint displacement (6.5 ± 4.1 mm) at maximum load (1.1 kN) exceeded crosshead displacement (3.9 ± 1.5 mm), with loads transferred across both facet joints. After fusion, facet displacement (2.0 ± 1.2 mm) reduced compared to pre-fusion, as was the crosshead displacement (2.2 ± 0.6 mm). Post-fusion loads (71.4 ± 73.2 N) transferred were reduced compared to pre-fusion levels (194.5 ± 125.4 N). Analysis of CT images showed no endplate damage post-fusion, whilst the IVD tissue: cement volume ratio did not correlate with the post-fusion behaviour of the specimens. Conclusion. An in vitro model showed significant facet movement reduction with stand-alone interbody cage placement. This technique identifies changes in facet movement post-fusion, potentially contributing to subsequent spinal degeneration, highlighting its utility in biomechanical assessment. Conflicts of interest. None. Sources of funding. This work was funded by EPSRC, under grant EP/W015617/1

Abstract. Objectives. While spinal fusion is known to be associated with adjacent disc degeneration, little is known on the role of the facet joints in the process, and whether their altered biomechanics following fusion plays a role in further spinal degeneration. This work aimed to develop a model and method to sequentially measure the effects of spinal fusion on lumbar facet joints through synchronisation of both motion analysis, pressure mapping and mechanical analysis. Methods. Parallel measurements of mature ovine lumbar facet joints (∼8yr old, n=3) were carried out using synchronised load and displacement measurements, motion capture during loading and pressure mapping of the joint spaces during loading. Functional units were prepared and cemented in PMMA endcaps. Displacement-controlled compression measurements were carried out using a materials testing machine (3365, Instron, USA) at 1 mm/min up to 950 N with the samples in a neutral position, while motion capture of the facet joints during compression was carried out using orthogonal HD webcams (Logitech, Switzerland) to measure the displacement of key facet joint features. The pressure mapping of load transfer during displacement was carried out using a flexible pressure sensor (6900 series, Tekscan, USA). Each sample was imaged at an isotropic resolution of 82 microns using a μCT scanner (XtremeCT, Scanco, Switzerland) to quantify the curvature within the facet joints. Results. Relative facet joint displacement under load, in a neutral position, showed more displacement (2.36 ±1.68 mm) compared to the cross-head when under compression (2.06 ±1.19 mm). Motion capture indicated the relative displacement of the facet joints was more posterior with some lateral motion. For five of the six facet joints, pressure measurement was possible only on 24±7 % of the surface due to the large change in curvature. Partially measured loads through the facets was 10.5 ±1.1 N. Conclusions. The relative displacement of the lumbar facet joints compared to the crosshead displacement was consistent with previous studies of cervical facet joints, despite the differences in anatomical geometry between cervical and lumbar joints. The difficulties in accurately measuring the load transfer through the facet joints was due to the age of the tissue and the degree of curvature of the facet joints. Synchronisation of the biomechanical data will provide a setup to assess the effect of interventions such as spinal fusion, with curvature-related issues unlikely to occur in human spines. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

We carried out a study to determine the effect of facet tropism on the development of adolescent and adult herniation of the lumbar disc. We assessed 149 levels in 140 adolescents aged between 13 and 18 years and 119 levels in 111 adults aged between 40 and 49 years with herniation. The facet tropism of each patient was measured at the level of the herniated disc by CT. There was no significant difference in facet tropism between the herniated and the normal discs in both the adolescent and adult groups, except at the L4-L5 level in the adults. Facet tropism did not influence the development of herniation of the lumbar disc in either adolescents or adults

Traumatic unilateral facet dislocation of the lumbosacral junction without fracture or with non-displaced fractures of adjacent vertebrae is extremely rare. We describe a case of a young male who sustained a unilateral facet dislocation of the lumbosacral junction in a motor vehicle accident. The unusual features of this case include an unremarkable physical and neurological examination on presentation and absence of other substantial vertebral or extra-vertebral injuries

Summary. Nucleotomy almost doubles the transmitted forces on the facet joints in human lumbar spine, regardless of the amount of removed nucleus pulposus. Introduction. Low back pain involves the lumbar facet joints in 15% to 45% of the cases. The surgical intervention, nucleotomy, might also lead to painful facets with a high risk; however, its mechanism is yet to be fully understood. The aim of this study is to reveal how a small amount of nucleus removal can change the force transmission on the facets. 1.1.1.1 Methods. Nine human lumbar motion segments with a median age of 48 years (interquartile range: 8.3) were tested quasi-statically (0.2 Hz) in extension and flexion (+/−5°) under constant compression loading (700 N). Specimens were tested in vitro by a servo-hydraulic test rig (MTS, USA) equipped with an additional superstructure enabling independent actuation of axial compression, extension-flexion and anterior-posterior shear on the top of the specimen. Forces and moments were measured beneath the specimen. The test method is based on recording intact and nucleotomy performed (range of removed nucleus 0.888–1.708 g) kinematics, which were applied in sequence, at different reduction stages of the same specimen. In the last steps, the facets were the only force transmitting structures, therefore, the load cell beneath the specimen revealed the force transmission on the facets. 1.1.2 Results. The average proportion of force transmitted through the facets increased significantly due to nucleotomy for both an intact capsular ligament (caps. lig.) (p=0.008) from 8.6% (5.2) to 15.8% (6.2), and without a caps. lig. from 8.4% (2.3) to 10.3% (4.9, p = 0.008). Amount of removed nucleus did not show statistically significant correlation to the force increase on facets due to nucleotomy (p>0.19). Forces on the facets were the highest in extension: fully intact 10.7% (6.6), nucleotomy with caps. lig. 19.0% (9.6), intact without caps. lig. 9.37% (3.42), and nucleotomy without caps. lig. 12.6% (6.5). Discussion. Results show, that even a small amount of nucleus removal increase the transmitted forces on facet joints, independent of the amount of removed nucleus. Therefore, a surgeon's decision on the amount of nucleus to remove might perhaps be based on aspects other than facet loading - for example, the avoidance of reherniation. Since facet loading is highest in extension, patients after nucleotomy should perhaps limit this motion as far as possible

Introduction. Mechanical integrity of patella can be weakened by the technique of removing the articulating surface. The senior author developed the technique of maintaining subchondral bone of the lateral patellar facet in early 1980s. Though laboratory studies have demonstrated deleterious effect of excessive resection of patella on the strains in the remaining bone under load; clinical studies have not shown the importance of strong subchondral bone of lateral facet to have an effect on patellar fracture prevalence. We present the results of our patellar resection technique preserving the subchondral bone of lateral facet. Methods. 393 TKRs were performed between 1989 and 1996 using cruciate substituting modular knee with recessed femoral trochlear groove and congruent patello-femoral articulation. 45 patients with 48 knees died and 37 patients with 41 knees were lost to follow-up. Three hundred and four knees were followed for an average 10 years (range 5 -16 years). Patellar surface was resected with an oscillating saw without the use of cutting guide. The medial facet and most of the articular cartilage of the lateral facet was resected, while preserving the subchondral bone of lateral facet. An all-polyethylene implant with single peg was used in most cases. Results. There have been two fractures in the cohort with prevalence of 0.66%. Eight TKRs were revised for synovitis and osteolysis. Patellar osteolysis was found in 4 of these cases, with loosening of 3 of these patellae, and 1 patellar fracture. Two patellar implants had global radiolucencies and were considered loose. The average knee score in unrevised knees improved from 48.6 to 92.2, while functional scores improved from 50 to 81.1. Conclusion. We believe that maintaining this anatomic landmark allows for preserved patellar strength, and in association with a femoral component with a recessed trochlear groove, has resulted in our low patellar fracture rate in primary TKR and revision cases for patellar osteolysis

Introduction and Aims: The aim of this paper is to review C1-C2 facet screw use in paediatric patients and to demonstrate that the technique plays an important role in patients with underlying anatomic abnormalities, which are common in children with cervical instability. Method: A chart review was conducted of all patients managed with C1-C2 facet screws from January 1, 1996 until July 30, 2003 present in the case database. All radiographs were obtained and reviewed. Post-operative and follow-up films were assessed for acceptable screw position and evidence of fusion. Results: C1-C2 facet screws were utilised in nine patients at British Columbia’s Children’s Hospital. The youngest patient treated was five years of age with a mean age for the group of 12. The group consisted of three Down syndrome patients and six with Os Odontoidium, two of which failed previous C1-C2 fusion. Two patients presented with an acute spinal cord injury. Pre-operative CT or MR imaging was used in all patients. Screw placement was unacceptable in one case. Post-operative Halo immobilisation was used in seven patients. Post-operative complications included one wound infection and four halo pin infections requiring treatment. No patients have required surgery at a mean follow-up of four years. C1-C2 facet screws are an important adjunct in a paediatric spine practice. This technique has a great advantage in Down syndrome patients who have a high rate of pseudoarthosis because of: ligamentous laxity, non-compliance with immobilisation and a high incidence of congenital deformities such as os odontoidium and incomplete posterior arch of C1. Conclusion: C1-C2 facet screws can be safely used in young children. The screws allow for fixation in the absence of an intact posterior arch. The technique has a great advantage in Down syndrome patients who have a high rate of pseudoarthosis due to congenital deformities, ligamentous laxity and non-compliance with immobilisation

Purpose: Facet joint arthrosis is an entity that can have a key role in the etiology of low back pain, especially with hyperextension, and is a key component of surgical planning, especially when considering disc arthroplasty. Plain films and MRI are most commonly utilized as the initial imaging of choice for low back pain, but these methods may not truly allow an accurate assessment of facet arthosis. Our purpose was to observe the inter- and intraobserver reliability of utilizing CT and MRI to evaluate facet arthrosis, the inter- and intraobserver reliability of the facet grading system, and the agreement of surgeons as to when to perform disc arthroplasty after the lumbar facets are evaluated. Method: A power analysis was performed which showed we would need 6 reviewers and 43 images to have 80% power to show excellent reliability. 102 CT and the corresponding MRI images of lumbar facets were obtained from patients who were to undergo lumbar spine surgery of any type. 10 spine surgeons and 3 spine fellows reviewed the randomized images at 2 time points, 3 months apart, graded the facet arthosis as well as indicated whether they would chose to perform a disc arthroplasty based on the amount of facet arthrosis. Both interobserver and intraobserver kappa values were calculated by result comparison between observers at the two time points and between CT and MRI images from the same patient. Results: interobserver reliability for MRI was 0.21 and 0.07(fair to slight agreement), and for CT was 0.33 and 0.27(fair agreement), for the spine surgeons and spine fellows respectively. The mean intraobserver reliability for MRI was 0.36 and 0.26 (fair agreement) and for CT was 0.52 and 0.51 (moderate agreement). The kappa value for agreement of whether to perform a disc arthroplasty after grading the facet arthrosis utilizing MRI was 0.22 (fair agreement) and utilizing CT was 0.33 (fair agreement) among the senior spine surgeons. Conclusion: The existing grading system for facet arthrosis and of whether to perform a disc arthroplasty utilizing the grading system has at best only fair agreement. CT is more reliable for grading facet arthrosis

The supraspinatus tendon (SP) often ruptures. Gray established that the tendinous insertion always attaches to the highest facet of the greater tubercle of the humerus. Our osteological study of 124 shoulders in men and women between the ages of 35 and 94 years refocuses on the humeral insertion of the SP in relation to infraspinatus (IS) and teres minor (TM). We found type-I SFs (cubic) in 53 shoulders (43%) and type-II SFs (rectangular or oblong) in 21 (17%). Type-III (ellipsoid) SFs were present in 20 shoulders (16%) and type-IV (angulated or sloping) in 11 (9%). SFs were type V (with tuberosity) in 12 shoulders (10%) and type VI (pitted) in three (2%). The facet area of the SP, IP and TM varied from 49 mm, 225 mm and 36mm2. Of the three muscles, the IS facet was consistently the largest (p < 0.05) and shaped rectangularly. The SP inserted in a cubic or rectangular facet format in 75% of people. SP facet-size may relate to tendon strength, degeneration and rupture. This information may contribute to the understanding of tears of the rotator cuff

Abstract. Objective. Flexible stabilisation has been utilised to maintain spinal mobility in patients with early-stage lumbar spinal stenosis (LSS). Previous literature has not yet established any non-fusion solution as a viable treatment option for patients with severe posterior degeneration of the lumbar spine. This feasibility study evaluates the mean five-year outcomes of patients treated with the TOPS (Total Posterior Spine System) facet replacement system in the surgical management of lumbar spinal stenosis and degenerative spondylolisthesis. Methods. Ten patients (2 males, 8 females, mean age 59.6) were enrolled into a non-randomised prospective clinical study. Patients were evaluated with standing AP, lateral, flexion and extension radiographs and MRI scans, back and leg pain visual analog scale (VAS) scores, Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ) and the SF-36 questionnaires, preoperatively, 6 months, one year, two years and latest follow-up at a mean of five years postoperatively (range 55–74 months). Flexion and extension standing lumbar spine radiographs were obtained at 2 years to assess range of motion (ROM) at the stabilised segment. Results. The clinical outcome scores for the cohort improved significantly across all scoring systems. Radiographs at 2 years did not reveal any loss of position or loosening of metal work. There were two incidental durotomies and no failures at 5 years with no patient requiring revision surgery. Conclusions. The TOPS implant maintains clinical improvement and motion in the surgical management of LSS and spondylolisthesis, indicating it can be considered an option for these indications

Introduction: The effect of facet tropism on the development of lumbar disc diseases has been investigated but is still controversy; moreover, there has been no study to be done on far lateral lumbar disc herniation (LDH). In the current study, the authors attempted to determine the differences of the degree of facet tropism and the degree of disc degeneration between far lateral and posterolateral LDHs. In addition, the effect of the difference of degree of facet tropism and the degree of disc degeneration on the development of far lateral LDH was investigated compared with posterolateral LDH. Methods: 38 LDHs (far lateral, n = 19; posterolateral, n = 19) who underwent posterior open discectomy or paraspinal approach were included in this study. The mean age was 52.3 years in far lateral LDH and 45.3 years in posterolateral LDH. The degrees of facet tropism and disc degeneration were measured at herniated disc level using MRI, and compared for the two different types of LDHs. Mann-Whitney U test and Spearman test were used for analysis. Results: There were significant statistical differences in the degree of facet tropism and the degree of disc degeneration. There was no significant correlation between the degree of facet tropism and the degree of disc degeneration in far lateral LDH. Discussion: The current study suggests that the differences of the degree of facet tropism and the degree of disc degeneration might be considered as the key factors to determine the development of far lateral LDH compared with posterolateral LDH

Aim: To investigate the efficacy of the Insall tube realignment procedure when used to treat osteoarthrosis of the lateral facet of the patello-femoral joint. This procedure has not been reported before for this indication. Methods: The operation is a quadricepsplasty that tilts the patella to enable it to articulate on its intact medial facet, decreasing the loading of the damaged lateral surface. An independent retrospective review was performed with clinical examinations and a score of pain and activity. The mean period of follow-up was 3.6 years with a minimum of one year. Results: There were 43 operations in 30 patients (12 males), with a mean age of 54 years. The patients graded their overall pain relief and functional change as being good to excellent in 32 knees, unchanged in four knees and worse in seven knees. The overall pre- and postoperative pain scores for sitting, walking, running and stair climbing all showed improvements. Ten patients felt some quadriceps weakness on descending stairs, but only one was clinically weak. There was an increase in the number of patients with severe pain on kneeling. Three patients with unsuspected tibio-femoral degenerative change seen at surgery all had poor results. Discussion: We recommend this relatively simple and effective operation for the surgical treatment of isolated lateral facet patello-femoral osteoarthritis

Background. Surgical resection of middle facet tarsal coalition is a well documented treatment option in symptomatic individuals that do not respond to conservative treatment. The ability to return to full recreational activity post resection may have implications on foot biomechanics and possibly degenerative changes in the subtalar and adjacent joints. Hypothesis. Open resection of middle facet tarsal coalitions should improve subtalar joint motion and biomechanical function and facilitate return to sports. Aim. The aim of this study was to assess the outcomes of open resection of middle facet tarsal coalitions (MFTCs) with particular emphasis on return to sports. Methods. Retrospective review of clinical and radiographic records of paediatric and adolescent patients who had open resection of middle facet tarsal coalitions. The ankle and hind foot were evaluated according to the American Orthopaedic Foot and Ankle Society Ankle-Hind foot Scale (AOFAS). We also quantified the return-to-activity time after tarsal coalition surgery. Results. We identified thirteen patients (Mean age; 13.7years Range; 7–21 years) with eighteen middle facet tarsal coalitions operated over a seven year period. Ten patients (12 feet) who underwent resection had an average return to recreational activity time of approximately twelve weeks and reported better exercise tolerance post resection. Conclusion. Surgical excision of middle facet tarsal coalitions has a favourable outcome with respect to return to sports

Hypertrophy of lumbar articular facets and dorsal joint capsule are well documented in degenerative instability, the molecular changes occurring in the extracellular matrix (ECM) are however unknown. The L4/L5 posterior articular complex was removed from seven individuals undergoing fusion for degenerative instability. After methanol fixation and decalcification in EDTA, specimens were cryosectioned at 12 μm and immunolabelled with monoclonal antibodies for collagen types I, II, III, V and VI; chondroitin-4 and 6 sulphates; dermatan and keratan sulphate; versican, tenascin, aggrecan and link-protein. Antibody binding was detected using the Vectastain ABC ‘Elite’ kit. Labelling patterns were compared to corresponding healthy specimens examined previously. In comparison, the degenerative capsule was more dense and hypertrophied and the enthesis more fibrocartilaginous, with immunolabelling extensive for collagen type II, chondroitin–6-sulfate, chondroitin-4-sulfate, aggrecan and link-protein. The articular surface showed extensive evidence of degeneration, while the thickened capsular entheses encircled the articular facets dorsally. Bony spurs capped with regions of cartilaginous metaplasia were prominent in this region, the ECM labelling strongly for type II collagen and chondroitin-6-sulfate. The hypertrophy of lumbar facet joints subject to instability of the functional spinal unit therefore appears to be due to proliferation of the capsular enthesis rather than the actual articular facet. In view of the physiological function of the dorsal joint capsule as a wrap-around ligament in assisting the limitation of axial rotation, the molecular changes found in degenerative instability suggest rotational instability, such as results from degenerative disc disease, to be a decisive factor in the development of spondylarthropathy. It is furthermore probable, that the pronounced sagittal joint orientation in degenerative instability is the result of reactive joint changes rather than a predisposing factor of instability

Introduction. Anteromedial gonarthrosis is a common well described pattern of knee osteoarthritis with cartilage wear beginning in the anteromedial quadrant of the medial tibial plateau in the presence of an intact and functioning ACL. It is well known that mechanical factors such as limb alignment and meniscal integrity affect the progression of arthritis and there is some evidence that the morphology of the tibial plateau may be a risk factor in the development of this disease. The extension facet angle is the angle of the downslope of the anterior portion of the medial tibial plateau joint surface in relation to the middle portion on a sagittal view. If this is an important factor in the development of AMG there may be potential for disease modifying intervention. This study investigates if there is a significant difference in this angle as measured on MRI between a study cohort with early AMG (partial thickness cartilage damage and intact ACL) and a comparator control cohort of patients (no cartilage damage and ACL rupture). Methods. 3 Tesla MRI scans of 99 patients; 54 with partial thickness cartilage damage and 44 comparitors with no cartilage damage (acute ACL rupture) were assessed. The extension facet angle was measured (Osirix v3.6) using a validated technique on two consecutive MRI T2 sagittal slices orientated at the mid-coronal point of the medial femoral condyle. (InterClass Correlation 0.95, IntraClass Correlation 0.97, within subject variation of 1.1° and coefficient of variation 10.7%). The mean of the two extension angle values was used. The results were tabulated and analysed (R v2.9.1). Results. Of the 99 knees, 38 were female and 61 male; 44 left knees and 55 right. The mean extension facet angle for the partial thickness group was 12.7° (SD 3.35) and for the comparator group 8.7° (SD 3.09). There was a significant difference between these 2 groups (Mann Whitney U, p<0.001). Although there were significantly more men than women in the comparator group, stratification analysis showed that there was no effect of gender on the mean extension facet angle. There was no effect of age on EFA in either group. Discussion. There is a significance difference in the extension facet angle between patients with AMG with only partial thickness cartilage loss and a comparator group. This has not been shown in a study group of this size before. Since none of the subjects had full thickness cartilage loss it is unlikely that this difference is due to bone attrition changing the angle as part of the disease process but this is an important area for further study. We believe that a higher medial tibial extension facet angle alters the mechanics within the medial compartment, placing these patients at higher risk of developing AMG. This may present an opportunity for risk factor modification, for example osteotomy

Introduction: Anteromedial gonarthrosis is a common well described pattern of knee osteoarthritis with cartilage wear beginning in the anteromedial quadrant of the medial tibial plateau in the presence of an intact and functioning ACL. It is well known that mechanical factors such as limb alignment and meniscal integrity affect the progression of arthritis and there is some evidence that the morphology of the tibial plateau may be a risk factor in the development of this disease. The extension facet angle is the angle of the downslope of the anterior portion of the medial tibial plateau joint surface in relation to the middle portion on a sagittal view. If this is an important factor in the development of AMG there may be potential for disease modifying intervention. This study investigates if there is a significant difference in this angle as measured on MRI between a study cohort with early AMG (partial thickness cartilage damage and intact ACL) and a comparator control cohort of patients (no cartilage damage and ACL rupture). Methods: 3 Tesla MRI scans of 99 patients; 54 with partial thickness cartilage damage and 44 comparitors with no cartilage damage (acute ACL rupture) were assessed. The extension facet angle was measured (Osirix v3.6) using a validated technique on two consecutive MRI T2 sagittal slices orientated at the mid-coronal point of the medial femoral condyle. (InterClass Correlation 0.95, IntraClass Correlation 0.97, within subject variation of 1.1° and coefficiant of variation 10.7%). The mean of the two extension angle values was used. The results were tabulated and analysed (R v2.9.1). Results: Of the 99 knees, 38 were female and 61 male; 44 left knees and 55 right. The mean extension facet angle for the partial thickness group was 12.7° (SD 3.35) and for the comparator group 8.7° (SD 3.09). There was a significant difference between these 2 groups (Mann Whitney U, p< 0.001). Although there were significantly more men than women in the comparator group, stratification analysis showed that there was no effect of gender on the mean extension facet angle. Discussion: There is a significance difference in the extension facet angle between patients with AMG with only partial thickness cartilage loss and a comparator group. This has not been shown in a study group of this size before. Since none of the subjects had full thickness cartilage loss it is unlikely that this difference is due to bone attrition changing the angle as part of the disease process but this is an important area for further study. We believe that a higher medial tibial extension facet angle alters the mechanics within the medial compartment, placing these patients at higher risk of developing AMG. This may present an opportunity for risk factor modification, for example osteotomy

We treated 36 patients with unilateral facet dislocations or fracture-dislocations of the cervical spine at the Mayo Clinic between 1975 and 1986. Adequate records were available for 34: ten patients were treated by open reduction and posterior fusion, and 24 by nonoperative management. Of these, 19 had halo traction followed by halo-thoracic immobilisation, four had a simple cervicothoracic orthosis, and one received no active treatment. Anatomical reduction was achieved more frequently in the operative group (60% compared with 25%). Nonoperative treatment was more likely to result in cervical translation on flexion/extension lateral radiographs, and in significant symptoms. Only 36% of the patients treated by halo traction achieved anatomical alignment; in 25% halo traction failed to achieve or maintain any degree of reduction. During halo-thoracic immobilisation, half of the patients lost some degree of reduction and patient satisfaction with the appliance was low. Open reduction and internal fixation of unilateral facet injuries gave better results. 6

Fractures of the anteromedial facet (AO/OTA 21-B1.1, O'Driscoll Type 2, subtype 3) are associated with varus posteromedial rotational instability of the ulnohumeral joint and early post-traumatic arthritis. The purpose of this study was to examine the stability of plate (locking and non-locking) vs screw constructs in the fixation of anteromedial coronoid facet fractures in a sawbone model. An anteromedial coronoid facet fracture (AO/OTA 21-B1.1) was simulated in 24 synthetic ulna bones. They were then assigned into 3 fracture fixation groups: non-locking plate fixation, locking plate fixation, and dual cortical screw fixation. An AO 2.0 mm screw and plate system was used for the plate fixation groups and 2.0 mm cortical screws were used for the screw-only group. Following fixation, each construct was potted in bismuth alloy and secured to a servohydraulic load frame. Each construct was cycled in tension and then in compression at 0.5Hz. For both cycling modalities, an incremental loading pattern was used starting at 40 N and increased by 20 N every 200 cycles up to 200N. Fracture fragment displacement was recorded with an optical tracking system. Following cyclic loading each construct was loaded to failure (displacement >2 mm) at 10mm/min. Tension cycling – All constructs in the plated groups (locking and non-locking constructs) survived the cyclic tension loading protocol (to 200N) with maximum fragment displacement of 12.60um and 14.50um respectively. There was no statistical difference between the plated constructs at any load level. No screw-only fixed construct survived the tension protocol with mean force at failure of 110N (range 60–180N). Compression Testing – All constructs in the plated groups (locking and non-locking constructs) survived the cyclic compression loading protocol (to 200N), while all but one of the screw-only fixation constructs survived. Fracture fragment displacement was significantly greater in the screw-only repair group across all loading levels when compared to the plated constructs. There was no statistically significant difference in fragment motion between the locking and non-locking groups. Failure Testing – The maximum load at failure in the screw-only group (281.9 N) was significantly lower than locking and non-locking constructs (587.0 N and 515.5N respectively, p <0.05). There was no difference between the locking and non-locking group in mean load to failure or mean stiffness. Screw construct stiffness (337.2 N/mm) was lower than the locking and non-locking constructs (682.9 N/mm and 479.1 N/mm respectively) however this did not reach statistical significance (p=0.051). Fixation of anteromedial coronoid fractures is best achieved with a plating technique. Locking plates did not offer any advantage over conventional plates. Isolated screw fixation might not provide adequate stability for these fractures which could result in loss of reduction leading to post-traumatic arthrosis or instabilility

Peroneal spastic flatfeet without coalition or other known etiologies in adolescence remain a challenge to manage. We present eight such cases with radiological and surgical evidence of bony abnormalities in the subtalar region just anterior to the posterior facet. All patients had presented as tertiary referrals with recalcitrant pain and had undergone a trial of orthotics and physiotherapy. Diagnostic workup included a clinical and radiographic evaluation. Clinical examination consisted of gait examination, foot alignment, range of motion, torsional profile of the lower limbs and marking of symptomatic foci. All patients had standing weightbearing AP and lateral projections of the foot and ankle. CT and/or MRI scans of the foot were performed in axial coronal and saggital planes. Coalitions and other intraarticular known pathologies were ruled out. All patients had bilateral flatfeet but unilateral peroneal spasm. All patients had an accessory talar facet in front of the posterior subtalar facet. This caused lateral impingement between the facet and the calcaneum, confirmed by bone edema around the sinus tarsi. All patients had stiff subtalar joints with very limited movement under anaesthesia, indicating peroneal muscle contracture. Patients were treated with a combination of facet excision, peroneal lengthening and calcaneal lengthening to correct the flatfoot and prevent lateral impingement. We propose a mechanism of subtalar impingement between the anterior extra-articular part of the talar lateral process and the Gissane angle and believe that resection of the accessory facet without addressing the the primary driving force for impingement, which is the structural malalignment in flatfeet, would only give partial relief of symptoms. This impingement appears to occur with growth spurts in adolescents, in patients with known flatfeet

We describe a lumbar facet syndrome in which disabling symptoms are associated with normal or near-normal plain radiographs. Local spinal fusion relieved symptoms in 12 patients; the excised facet joint surfaces showed some of the histological changes seen in chondromalacia patellae and in osteoarthritis of other large joints. The most frequent change was focal full-thickness cartilage necrosis or loss of cartilage with exposure of subchondral bone, but osteophyte formation was remarkably absent in all specimens. We suggest that there are both clinical and histological similarities between the facet arthrosis syndrome and chondromalacia patellae. Facet arthrosis may be a relatively important cause of intractable back pain in young and middle-aged adults

Painful peroneal spastic flatfeet without coalition or other known etiologies in adolescence, remains a difficult condition to treat. We present eight such cases with radiological and surgical evidence of bony abnormalities in the lateral subtalar region just anterior to the posterior facet. All patients had presented as tertiary referrals with recalcitrant pain and had undergone a trial of orthotics and physiotherapy. Diagnostic workup included a clinical and radiographic evaluation. Clinical examination consisted of gait examination, foot alignment, range of motion, torsional profile of the lower limbs and marking of symptomatic foci. All patients had standing weightbearing anteroposterior and lateral projections of the foot and ankle, CT and/or MRI scans of the foot. Coalitions and other known intra-articular pathologies like subtalar arthritis were ruled out. All patients had bilateral flatfeet but unilateral peroneal spasm. All patients had an accessory anterolateral talar facet (ATF) which was arising as an anterior and distal extension of the lateral process of the talus. This caused lateral impingement between the facet and the calcaneum, confirmed by bone edema around the sinus tarsi and marked at the apex of the angle of Gissane on MRI scans. All patients had stiff subtalar joints with very limited movement under anaesthesia, indicating peroneal muscle contracture. Patients were treated with a combination of facet excision, fractional peroneal and gastrosoleus lengthening and calcaneal lengthening to correct the flatfoot and prevent lateral impingement

Introduction. Historically, surgeons have focused on isolated simple coalition resection in symptomatic tarsal coalition with concomitant rigid flat foot. However, a review of literature suggests that coalitions with severe preoperative planovalgus malposition treated with resection alone are associated with continued disability and deformity. We believe that concomittant severe flatfoot should be considered as much as a pathological component and pain generator as the coalition itself. Our primary hypothesis is that simple resection of middle facet tarsal coalitions and simultaneous flat foot reconstruction can improve clinical outcomes. Methods. Thirteen consecutively treated patients (eighteen feet) were retrospectively reviewed from the senior author's practice. Clinical examination, American Orthopaedic foot and Ankle Society (AOFAS) hindfoot scores, and radiographic assessments were evaluated after resection of middle facet tarsal coalitions with simultaneous flat foot reconstruction. Results. All patients with resection and simultaneous flat foot reconstruction (calcaneal lengthening, medial cuneiform osteotomy) were satisfied and would have the same procedure again. Most patients were able to return to a higher level of sporting activity compared with preoperative ability. None of the patients had a fair or poor outcome as adjudged by their AOFAS scores. Conclusion. Our study shows that concomittant flatfoot reconstruction in patients with symptomatic middle facet tarsal coalition increased hindfoot motion, corrected malalignment and significantly improved pain. We believe that coalition resection and concomitant flatfoot reconstruction is better option than surgical resection alone or hindfoot fusion in this cohort of patients. Triple arthrodesis should be reserved as a salvage procedure

The requirements for a motion segment fusion for degenerative disc disease are relief from symptoms from a solid union with minimal damage to surrounding tissue. This is possible with the ‘Mini PLIF’ using the B Twin cages and facet screws. This procedure produces reliable relief of symptoms with a solid fusion. The use of facet screws mean that the nerve supply of the paraspinal muscles is protected. Between June 2002 and February 2006 35 patients underwent this procedure. There were 13 males and 22 females with an average age of 40 years from all walks of life. 30 patients had back and leg pain with only 5 having solely back pain. 28 patients had surgery at L5/ S1 with 4 patients at L4/5 and 3 at both. The median pre operation ODI was 53 (IQR 60–44) and at one year follow up the ODI was 24 (IQR 37–13). There were two complications of superficial infection and two pseudarthroses requiring pedicle screw constructs and revision bone grafting to achieve union. We believe this procedure demonstrates good relief from symptoms with a good fusion rate preserving the paraspinal muscles

Aim. Historically, surgeons have focused on isolated simple coalition resection in symptomatic tarsal coalition with concomitant rigid flat foot. However, recent evidence suggests that coalitions with severe preoperative planovalgus malposition treated with resection alone are associated with continued disability and deformity. We believe that concomitant severe flatfoot should be considered as much as a pathological component and pain generator as the coalition itself. Our primary hypothesis is that simple resection of middle facet tarsal coalitions and simultaneous flat foot reconstruction can improve clinical outcomes. Method. We identified eleven children (13 feet) who had resections of middle facet tarsal coalitions with or without complex foot reconstruction (calcaneal lengthening, medial cuneiform osteotomy) for concurrent severe planovalgus between 2003 and 2011. Clinical examination, American Orthopaedic Foot and Ankle Society (AOFAS) hind-foot scores, and radiographic assessments were evaluated after resection of middle facet tarsal coalitions with simultaneous flat foot reconstruction. Results. Isolated coalition resection provided short to intermediate term pain relief for three children that had this as a solitary procedure. Calcaneal lengthening osteotomy performed as an additional procedure in patients with very severe and stiff planovalgus provided excellent correction and symptomatic pain relief in all six patients (Mean AOFAS: 91). Two patients had insertion of sinus tarsi implants in addition to resection also had satisfactory hind foot function (Mean AOFAS: 87.3) post operatively. Conclusion. This study shows that calcaneal lengthening osteotomy in addition to coalition resection in patients with severe rigid flat feet provides excellent pain relief and function. Rigid flat feet should be considered as a significant contributor to the pain complex in this cohort of patients

The aim of this study was to assess the benefit and durability of isolated lateral release for advanced osteoarthritis of the lateral facet of the patellofemoral joint. A retrospective study of 23 knees in 20 patients who had isolated lateral patellofemoral joint arthrosis treated with arthroscopic debridement and limited open lateral release was carried out. Patients completed a specific patellofemoral questionnaire (35 points) including questions for pain and functional improvement and pain and functional Fisual Analogue Scores (VAS). Eighteen knees in 15 patients were clinically and radiologically examined. Patients averaged 50 years of age and 2 years from surgical treatment. Visual analogue scores for pain improved 28% and function 40% with little radiological change. Similar improvements were seen in the patello femoral specific questionnaire. The results appeared to be durable over the 2 year follow up period. Lateral release for treatment of isolated arthrosis of the lateral compartment of the patellofemoral joint is an effective, reliable, durable procedure in carefully selected patients

Bilateral interlocking of the articular facets of the cervical spinal column results from excessive flexion. Unilateral interlocking (hemiluxation) results from simultaneous excessive flexion and rotation. Patients with hemiluxation of the cervical spine often have only mild complaints and the clinical signs may be slight. The diagnosis is made radiologically, but it is often overlooked. Various forms of treatment may give good results. In recent hemiluxation, reduction is advisable to promote recovery of radicular symptoms. The effect of reduction on spinal cord symptoms is uncertain. Manual reduction under general anaesthesia is usually successful, with the possible exception of some cases of interlocking at C.6-C.7, or C.7-T.1. Skull traction with weights of 5 to 10 kilograms even when prolonged is hardly ever successful; with weights of 10 kilograms or more there is a chance of success. Surgical reduction is not always necessary. A hemiluxation of more than two weeks' standing may still be reduced but non-operative methods offer little chance of success. In this series there has been no aggravation of the neurological deficit after reduction. Although hemiluxation shows a tendency to spontaneous stabilisation it is wise in our opinion to apply some form of fixation. The selection of the method of fixation depends on the neurological picture and on the estimated degree of instability. The latter depends on the presence or absence of additional damage to the interlocked and adjacent vertebrae. Manual reduction by means of traction in the longitudinal axis of the cervical spine under general anaesthesia with muscle relaxation, followed by immobilisation in a plaster jacket (Minerva type) for three months is successful in many cases. If surgical stabilisation is considered necessary an attempt at manual reduction should be made before operation so that when the patient is placed on the table the cervical spinal canal has regained its normal shape. In general, sufficient stability will have been achieved after approximately three months, so that for hemiluxations of more than three months duration surgical treatment will only rarely be necessary. Figure 11 shows the methods of treatment that we advise

We report 13 patients with missed bilateral facet dislocation of the lower cervical spine who subsequently developed severe spinal-cord involvement. There were more women and the patients were older than in most groups with spinal injury. The commonest cause was a fall, and paralysis appeared from six to 48 hours after injury in most patients. Ten patients made some recovery after late reduction but three remained totally paralysed. We discuss the pathogenesis of the late cord lesion and the reasons for delay in diagnosis

Awake Rapid Heavy-Weight Closed Reduction (ARHWCR) with weights from 18 to 72 kg was used to reduce six unilateral and nine bilateral cervical facet dislocations. Frankel grading ranged from A to E. Reduction was achieved in all 15 patients with no neurological deterioration. Motor ASIA score improved from a prereduction mean of 64 points to 73 after reduction. Before and after reduction, MRI studies were done on all 15 patients. ARHWCR was done irrespective of the MRI findings. The MRI results were evaluated by five orthopaedic surgeons, five neurosurgeons and five radiologists. The radiologists reported 55% disc herniation in four neurologically-intact patients. On pre-reduction MRI, 34% of anterior longitudinal ligaments and 64% of posterior longitudinal ligaments were reported to be disrupted. They were reported intact on post-reduction MRI. These findings indicate that MRI studies may be open to misinterpretation. Viewing the prereduction MRI, the orthopaedic and neurosurgeons opted for surgical decompression and reduction in 53% of cases. Looking at the post-reduction MRI, they felt that reduction was adequate in 80.6% of cases, but on personal judgment believed that surgical decompression might be of benefit in the remaining 19.4%. ARHWCR is an effective, safe and rapid way of relieving cord compression. Prereduction MRI, irrespective of the patient’s neurological status, is not indicated in acute cervical facet dislocations and can lead to unnecessary surgical intervention

The cervical spine is the most vulnerable segment in high velocity injuries. Bifacet dislocations are associated with significant soft tissue damage and neurological deficit. Management of delayed presentation of cervical facet dislocations, which are not uncommon, is varied. The aims of this study are to create awareness and to develop a management strategy. We retrospectively reviewed 14 patients (10 men and four women) with chronic dislocations treated over 4 years. The mean age was 42.5 years (23 to 62). The delay in presentation ranged from 15 to 135 days. Seven patients had neurological deficit. All patients underwent CT scan and MRI. Common areas of involvement were C6/7 (five patients) and C5/6 (four patients). Associated fracture of posterior elements was identified in 40% of patients. In two patients sequestrated disc ruptured into the canal. All patients underwent surgical reduction and stabilisation, with eight having one-stage and six two-stage surgery. The sequence of one-stage surgery was posterior release, reduction (facet reduction/facetectomy), anterior discectomy and anterior fusion. In three patients with sequestrated discs, anterior decompression preceded posterior release and finally anterior fusion. The six patients who had staged surgery had a prolonged delay (over 3 months) in presentation. Posterior release was followed by an anterior decompression, then a 7 to 10-day period of traction reduction and finally anterior fusion. None of our patients developed neurological deficit. Three patients improved from Frankel-C to Frankel-D. We recommend that the sequence of surgery should be posterior release/reduction and then anterior decompression and anterior fusion. However, in chronic cases, staged reduction and fusion is a viable option

Objective. To identify any difference in clinical outcome between Intra-Capsular facet (IF) and Peri-facet (PF) injections in patients with low back pain (LBP). IF and PF joint steroid injections have been used for treatment of LBP with varied reports of pain relief for many years. Methods. Patients randomised into IF and PF groups. Bilateral L4/5 and L5/S1 levels injected. 40mg of Depo-Medrone with Lignocaine (total 1ml) in IF group. 80mg of Depo-Medrone with 1ml of 0.5% Chirocaine (total 3ml) in PF group. Pain visual analogue score (VAS) and analgesic chart – completed till six months. Results. Eighty eight total, 14 withdrew, 69 with feedback available. Sixty-three (91%) had significant pain relief a week following injection, 86% and 94% in IF & PF groups. Mean duration of pain relief was 12.4 weeks (IF-12.2, PF-12.5). Mean change in VAS before & after injection was 4 (IF-4, PF-4). Mean change in analgesic use before & after injection was 2 tablets. (IF-2.9, PF-2.3). Radiation dose area product (DAP) for IF injections- 603 and PF- 45 mGy.cm. 2. 45 (51%) came for repeat injections, 19 & 26 in IF & PF groups. Conclusions. Majority of patients had pain relief with no statistically significant difference between 2 groups in change in pain severity, duration of pain relief or change in analgesic intake. Significant change in VAS after injection in both groups (from 7 to 3). Pain relief for a mean duration of 12.4 weeks. PF - technically easier- 9 patients randomised to IF group had to have PF injections (facet joint osteophytes). Radiation doses much higher for IF injections even in expert hands (P=0.007). It took double the time to perform IF injections compared to PF (30 and 15 minutes)

Cervical total disc replacement has been in practice for years now as a viable alternative to cervical fusion in suitable cases, aspiring to preserve spinal motion and prevent adjacent segment disease. Reports are rife that neck pain emerges as an annoying feature in the early postoperative period. The facet joint appears to be the most likely source of pain.

50 patients were prospectively followed up through 5 years after having received disc replacement surgery, indicated for symptomatic soft disc herniation of the cervical spine presenting with radiculopathy.

We excluded those with degenerative trophic changes of the cervical spine, focal instability, trauma, osteoporosis, previous cervical spine surgery, previous infection, ossifying axial skeletal disease and inflammatory spondyloarthritides. The device used was an unconstrained implant with stabilizing teeth. Over the 5 years, we studied their postoperative comfort level via the Neck Disability Index (NDI) and Visual Analogue Score (VAS). Pre-operative and post-operative analysis of the sagittal axis and of involved facet joints were done.

22 patients suffered postoperative neck pain as reflected by the NDI and VAS scores. Of these, 10 reported of neck pain even 24 months after surgery. However, none were neurologically worse and all patients returned to their pre-morbid functions and were relieved of pain by 28 months. All 22 patients reported of rapid dissolution of neckache after peri-facetal injections of steroids were done under image guidance.

We draw attention to the facet joint as the pain generator, triggered by inappropriate implant height, eccentric stresses via hybrid constructs, eccentric loading due to unconstrained devices and unaddressed Luschka joint degeneration. Such factors require careful selection of patients for surgery, necessitate proper pre-operative templating and call for appropriate technical solutions during surgery.

Introduction

Facet joint osteoarthritis (FJOA) is a prominent clinical hallmark of degenerative spine disorders. During disease progression, cartilage and subchondral bone tissues undergo increased turnover and remodeling. The structural changes to the subchondral tissue of FJOA have not been studied thus far. In this study, we performed a micro computed tomography (µCT) study of the subchondral cortical plate (SCP) and trabecular bone (STB) in FJOA and determined osteoarthritis-specific alterations.

Introduction: The purpose of this study was to speculate the process of degenerative changes in the lumbar spine.

Methods: The subjects were 80 (45 men and 35 women) patients aged 39–92 years (mean, 67.2 years) with degenerative change of the facet joints who had undergone surgery. These patients were divided between two groups using Gibson’s classification in T2-weighted MR images at L4-5 or L5-S1. The patients with 3 or 4 grade were regarded as D(+); otherwise as D(−). The number of patients, age, gender and the presence or absence of painful arthrosis in the limbs in each group were examined.

Results: There were 47 (20 men, 27 women) patients with a mean age of 67.5 years in the D(+) group, 33 patients (25 men, 8 women; mean age, 66.6) in the D(−) group. Painful arthrosis in the limbs was more often observed in the D(−) group than in the D(+) groups.

Conclusion: In the process of degenerative change of facet joints, some patients did not have severe disc degeneration. Most patients in the D(−) group were men and had painful arthrosis in the limbs.

Background: Lumbar facet joints are a frequent source of pain in degenerative lumbar spine disease. In many cases, they may actually be the predominant source of pain.

Material & Methods: Our target criteria were low back pain (VAS 0 10), back pain related limitation in daily activities and general acceptance of the treatment method. Inclusion criteria: Deep-seated non-sciatic low back pain, failure of conservative measures, positive diagnostic medial branch blocks. Exclusion criteria: Previous spinal surgery, relevant spinal stenosis, activated osteochondrosis, radicular pain. Diagnostic blocks were performed under fluoroscopy, improvement in low back pain of more than 50% for more than 3 hours was considered a positive block. Cryodenervation was performed also under fluoroscopy at a separate appointment. Since June 2002, 52 patients (average age 56) were entered into the study. 2 Patients were lost to follow-up and 2 others had to be excluded, so that 48 patients were available for evaluation. At present, we have a 3-month follow-up for all 48 patients, a 6-month follow-up for 44 patients, a 12-month follow-up for 32 patients and an 18-month follow-up for 19 patients.

Results: 2 weeks after treatment, 65 % of patients reported significant improvement, 35 % reported little or no change in pain. The average VAS of the complete study group dropped from 7.7 preoperatively to 3.3 at two weeks and to 3.45 at three and eighteen months postoperatively (p < 0.05). Limitation in daily activities improved parallel to the reduction in low back pain and 33 out of 48 patients would have the procedure performed again while 2 remained undecided

Conclusion: Percutaneous medial branch cryodenervation is a safe and effective means for the treatment of lumbar facet joint pain.

Purposes of the study and background: Diagnostic interventional procedures are often performed on patients who suffer from cervical facet joint pain and discogenic pain emanating from the cervical region. These procedures require radiographic imaging to confirm placement of instruments e.g. needles. However, these techniques are unable to provide real-time images hence prolonging the intervention. It would be of benefit to have an imaging tool that is capable of visualising needle insertion in real-time whilst preventing side effects. The purpose of this study was to determine the ultrasonic appearance of cervical facet joints in vivo and describe a standardized transducer position to visualise intervertebral discs and facet joints.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using an 8-16MHz linear array transducer (Diasus Dynamic Imaging). Subjects were scanned in a prone, lateral position. The transducer was placed in the posterior triangle orientated longitudinally, initially along the posterior border of sternocleidomastoid and then moved in a cranial-caudal direction. By adjusting the angle (in the antero-posterior direction) of the transducer about a fixed position; facet joints and discs were located. The characteristic V shaped appearance of the facet joint emanates from the hyperechoic signal of the closely spaced transverse processes of adjacent vertebra (Figure1). Disc regions appeared as areas of high signal penetration into the spine with low amplitude signals returning from the disc.

Conclusion: The detail of facet joint and disc anatomy captured using ultrasound reveal it to be a viable imaging tool for interventional procedures. Noteworthy advantages of ultrasound include: its ability to provide real-time images economically, the option of portability and no known side effects.

Introduction: Osteoarthritis (OA) of the apophyseal (facet) joints often appears to follow degenerative changes in the adjacent intervertebral discs. We test the hypothesis that facet joint OA is directly related to high compressive load-bearing resulting from disc degeneration.

Methods: Thirty six cadaveric thoraco-lumbar “motion segments” consisting of two vertebrae and the intervening disc and ligaments, were obtained from 22 human cadavers aged 64–92 yrs (mean 77 yrs). Each was subjected to a constant compressive load of 1.5 kN while the distribution of compressive stress was measured along the mid-sagittal diameter of the intervertebral disc, using a miniature pressure transducer, side-mounted in a 1.3 mm-diameter needle. Measurements of compressive “stress” were summed over area to give the compressive force resisted by the disc. This was subtracted from the applied 1.5 kN to indicate compressive load-bearing by the neural arch, including the apophyseal joints. After mechanical testing, the cartilage of each apophyseal joint surface was graded for degree of degeneration. Joints were then macerated, and each bony joint surface was scored for the following four degenerative changes, according to established criteria: marginal osteophytes, pitting, bony contour change, and eburnation. The four bone scores were summed and used to represent the severity of OA for that joint surface, and values were then averaged for the two facet joints (four surfaces) of each motion segment.

Results: Cartilage degeneration and summed bone scores both increased with age, and with each other (P< 0.01). Neural arch load-bearing ranged from 5%–96% (mean 45%) of the applied 1.5 kN compressive force, with values over 50% being found only in specimens with degenerated intervertebral discs. Facet joint summed bone score increased with neural arch load-bearing (P< 0.01), especially when the latter exceeded 50%.

Conclusion: High apophyseal joint load loading, equivalent to neural arch compressive load-bearing above 50%, is strongly associated with severe OA changes in the apophyseal joints. Associations were stronger for bone rather than cartilage changes, possibly because pathological load-bearing by the facet joints can occur between the tip of the inferior articular process and the adjacent lamina, substantially by-passing the articular (cartilage) surfaces.

Introduction The mechanisms underlying chronic back pain are not well understood, however, disc degeneration and facet joint arthrosis have been suggested to be two major pain sources. Nitric oxide (NO) is an oxygen free radical which is involved in variety physiological and pathological events. Increased concentrations of NO have been demonstrated with direct or indirect methods in temporomandibular (Takahashi T et al. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.1999) and knee joints (Karan A et al. Clin Rheumatol. 2003) with osteoarthrosis. The aims of the study were 1. To investigate if real-time NO concentrations can be measured in the perifacetal region and 2. To estimate perifacetal NO levels in patients with facet joint osteoarthrosis associated chronic low back pain and compare it with that of healthy controls, and 3. To investigate if perifacetal NO levels is discriminative for subsets of patients with facet joint osteoarthrosis.

Methods Patients with at least six months duration of chronic low back pain with signs of facet joint osteoarthrosis on CT and/or MRI, were included in the study (n=26). Healthy volunteers were enrolled as controls (n=7). A detailed questionnaire including visual analogue scale (VAS) was completed by the patients before and six weeks after the NO measurements. Nitric oxide was measured with a custom designed electrochemical real-time nitric oxide sensor (World Precision Instruments, Sarasota, Fl). The NO sensor has a detection limit of less than 0.3 nM, a linear response to NO concentrations up to 100 μM and can discriminate between NO and closely related substances such as nitrite (Zhang X et al; Electroanalysis 2002). The NO sensor was inserted into the facet joint through a 20 gauge needle under fluoroscopic guidance in patients and controls. All patients received corticosteroids (0.4 ml Celestone®) and local anaesthetic (0.5–1.0 ml Marcain®) in the perifacetal region following the NO measurements. Descriptive parameters are expressed as mean (± SEM) and Mann-Whitney’s test was used for statistical comparison between groups.

Results It was possible to obtain NO measurements from all participants. No adverse effects were noted. The patients with chronic low back pain demonstrated 3-fold higher concentrations of nitric oxide in the perifacetal region compared to the healthy controls (1.66±1.39 vs. 0.46±0.37 nM, p=0.007). No association between nitric oxide concentration and pain-duration or pain-level (VAS) was detected. However, patients with a positive response to local anaesthetics and corticosteroid injection (detected as a reduction of VAS at a minimum of 20 mm) at the six week follow-up visit had 25% higher concentrations of nitric oxide when compared to patients who had a less than 20 mm decrease in VAS. p=0.02

Discussion The study demonstrates that measurement of NO with a real time-sensor around the facet joints is feasible and safe. The findings of higher concentrations of NO in the perifacetal region in chronic low back patients compared to healthy controls indicate that the degenerative process of the joints may cause increased NO production. Patients that responded to corticosteroid/local anaesthetic infiltration had higher NO concentrations in the perifacetal region compared to patients without response. This observation indirectly suggests a more pronounced inflammatory process in the responding patients.

A case of a ganglion arising from a distal lumbar articular facet joint associated with low back pain and sciatica is reported and the pertinent literature reviewed.

To determine whether spinal facet osteoblasts at the curve apex display a different phenotype to osteoblasts from outside the curve in patients with adolescent idiopathic scoliosis (AIS). Intrinsic differences in the phenotype of spinal facet bone tissue and in spinal osteoblasts have been implicated in the pathogenesis of AIS. However, no study has compared the phenotype of facet osteoblasts at the curve apex with the facet osteoblasts from outside the curve in patients with AIS. Facet bone tissue was collected from three sites, the concave and convex side at the curve apex and from outside the curve from three female patients with AIS (aged 13–16 years). Micro-CT analysis was used to determine the density and trabecular structure. Osteoblasts were then cultured from the sampled bone. Osteoblast phenotype was investigated by assessing cellular proliferation (MTS assay), cellular metabolism (alkaline phosphatase and Seahorse Analyser), bone nodule mineralisation (Alizarin red assay), and the mRNA expression of Wnt signalling genes (quantitative RT-PCR). Convex bone showed greater bone mineral density and trabecular thickness than did concave bone. The convex side of the curve apex exhibited a significantly higher proliferative and metabolic phenotype and a greater capacity to form mineralised bone nodules than did concave osteoblasts. mRNA expression of SKP2 was significantly greater in both concave and convex osteoblasts than in non-curve osteoblasts. The expression of SFRP1 was significantly downregulated in convex osteoblasts compared with either concave or non-curve. Intrinsic differences that affect osteoblast function are exhibited by spinal facet osteoblasts at the curve apex in patients with AIS

Aims. The purpose of this retrospective study was to investigate the clinical relevance of increased facet joint distraction as a result of anterior cervical decompression and fusion (ACDF) for trauma. Patients and Methods. A total of 155 patients (130 men, 25 women. Mean age 42.7 years; 16 to 87) who had undergone ACDF between 1 January 2001 and 1 January 2016 were included in the study. Outcome measures included the Neck Disability Index (NDI) and visual analogue scale (VAS) for pain. Lateral cervical spine radiographs taken in the immediate postoperative period were reviewed to compare the interfacet distance of the operated segment with those of the facet joints above and below. Results. There was a statistically significant relationship between greater facet distraction and increased NDI and VAS pain scores. This was further confirmed by Spearman correlation, which showed evidence of a moderate correlation between both NDI score and facet joint distraction (Spearman correlation coefficient 0.34; p < 0.001) and VAS score and facet distraction (Spearman correlation coefficient 0.52; p < 0.001). Furthermore, there was a discernible transition point between outcome scores. Significantly worse outcomes, in terms of both NDI scores (17.8 vs 8.2; p < 0.001) and VAS scores (4.5 vs 1.3; p < 0.001), were seen with facet distraction of 3 mm or more. Patients who went on to have a posterior fusion also had increased NDI and VAS scores, independent of facet distraction. Conclusion. After undergoing ACDF for the treatment of cervical spine injury, patients with facet joint distraction of 3 mm or more have worse NDI and VAS pain scores. Cite this article: Bone Joint J 2018;100-B:1201–7

Ulnocarpal impaction (UCI) is a common cause of ulnar-sided wrist pain. UCI typically occurs in wrists with positive ulnar variance, which causes altered loading mechanics between the ulnar head, lunate and triquetrum. However, many individuals with positive ulnar variance never develop UCI, and some with neutral or negative ulnar variance do experience UCI. This suggests that other variables contribute to the development of UCI. Suspected culprits include lunate morphology, and dynamic changes with loaded (grip) pronation. If these anatomic variations are contributing to UCI, we expect them to influence functional impairment scores. Therefore, the objective of this study was to evaluate the relationship between radiographic parameters and pre-surgical upper extremity patient-rated outcomes scores (PROS) in patients with a diagnosis of UCI. Retrospective cohort study of patients undergoing ulnar shortening osteotomy or arthroscopic wafer procedure for UCI. Data derived from prospectively collected departmental database that captured demographic, clinical, functional and radiographic information. Radiographic parameters evaluated were: lunate morphology [presence vs. absence of hamate facet; Antuna-Zapico (A-Z) classification], and dynamic changes on grip view [difference in lunate-ulnar head distance (LUD); difference in lunate uncovering index (LUI)]. PROS assessed were QuickDASH and Patient-Rated Wrist Evaluation (PRWE) scores, collected at patient enrolment. ANOVA was used to assess for differences in PROS between A-Z classification groups. Student's t-test was used to assess for differences in PROS based on presence/absence of a hamate facet. Regression analysis evaluated a relationship between change in LUD with grip and PROS, and change in LUI with grip and PROS. Preliminary analysis included 23 wrists, with a mean patient age of 48.9 years [standard deviation (SD) 14.5 years]. Forty-eight percent were male, and the dominant limb was involved in 52.2% of cases. Average QuickDASH and PRWE scores at enrolment were 50.9 (SD 22.2) and 62.2 (SD 22.0), respectively. Assessment of radiographs revealed 17 patients (73.9%) without a hamate facet. Five patients (21.7%) had A-Z Type I lunate morphology, and nine (39.1%) had Type II and Type III morphology, respectively. ANOVA revealed no differences in enrolment QuickDASH (p = 0.185) or PRWE (p = 0.256) scores between A-Z classification groups. Similarly, Student's t-test found no difference based on presence/absence of a hamate facet (QuickDASH p = 0.594; PRWE p = 0.573). Regression analysis revealed no relationship between change in LUD with grip and PROS (QuickDash R2 = 0.020, p = 0.619; PRWE R2 = 0.009, p = 0.733), and no relationship between change in LUI with grip and PROS (QuickDash R2 = 0.000, p = 0.913; PRWE R2 = 0.010, p = 0.722). Preliminary results suggest no relationship between A-Z classification lunate morphology, presence/absence of a hamate facet, change in LUD, or change in LUI and pre-surgical PROS. It is unclear if our findings represent the true relationship between these radiographic parameters and PROS, or reflect our preliminary sample size. Data analysis is ongoing to add clarity to this question

Despite the current trend favoring surgical treatment of displaced intra-articular calcaneal fractures (DIACFs), studies have not been able to demonstrate superior functional outcomes when compared to non-operative treatment. These fractures are notoriously difficult to reduce. Studies investigating surgical fixation often lack information about the quality of reduction even though it may play an important role in the success of this procedure. We wanted to establish if, amongst surgically treated DIACF, an anatomic reduction led to improved functional outcomes at 12 months. From July 2011 to December 2020, at a level I trauma center, 84 patients with an isolated DIACF scheduled for surgical fixation with plate and screws using a lateral extensile approach were enrolled in this prospective cohort study and followed over a 12-month period. Post-operative computed tomography (CT) imaging of bilateral feet was obtained to assess surgical reduction using a combination of pre-determined parameters: Böhler's angle, calcaneal height, congruence and articular step-off of the posterior facet and calcaneocuboid (CC) joint. Reduction was judged anatomic when Böhler's angle and calcaneal height were within 20% of the contralateral foot while the posterior facet and CC joint had to be congruent with a step-off less than 2 mm. Several functional scores related to foot and ankle pathology were used to evaluate functional outcomes (American Orthopedic Foot and Ankle Score - AOFAS, Lower Extremity Functional Score - LEFS, Olerud and Molander Ankle Score - OMAS, Calcaneal Functional Scoring System - CFSS, Visual Analog Scale for pain - VAS) and were compared between anatomic and nonanatomic DIAFCs using Student's t-test. Demographic data and information about injury severity were collected for each patient. Among the 84 enrolled patients, 6 were excluded while 11 were lost to follow-up. Thirty-nine patients had a nonanatomic reduction while 35 patients had an anatomic reduction (47%). Baseline characteristics were similar in both groups. When we compared the injury severity as defined by the Sanders’ Classification, we did not find a significant difference. In other words, the nonanatomic group did not have a greater proportion of complex fractures. Anatomically reduced DIACFs showed significantly superior results at 12 months for all but one scoring system (mean difference at 12 months: AOFAS 3.97, p = 0.12; LEFS 7.46, p = 0.003; OMAS 13.6, p = 0.002, CFSS 7.5, p = 0.037; VAS −1.53, p = 0.005). Univariate analyses did not show that smoking status, worker's compensation or body mass index were associated with functional outcomes. Moreover, fracture severity could not predict functional outcomes at 12 months. This study showed superior functional outcomes in patients with a DIACF when an anatomic reduction is achieved regardless of the injury severity

Despite the current trend favoring surgical treatment of displaced intra-articular calcaneal fractures (DIACFs), studies have not been able to demonstrate superior functional outcomes when compared to non-operative treatment. These fractures are notoriously difficult to reduce. Studies investigating surgical fixation often lack information about the quality of reduction even though it may play an important role in the success of this procedure. We wanted to establish if, amongst surgically treated DIACF, an anatomic reduction led to improved functional outcomes at 12 months. From July 2011 to December 2020, at a level I trauma center, 84 patients with an isolated DIACF scheduled for surgical fixation with plate and screws using a lateral extensile approach were enrolled in this prospective cohort study and followed over a 12-month period. Post-operative computed tomography (CT) imaging of bilateral feet was obtained to assess surgical reduction using a combination of pre-determined parameters: Böhler's angle, calcaneal height, congruence and articular step-off of the posterior facet and calcaneocuboid (CC) joint. Reduction was judged anatomic when Böhler's angle and calcaneal height were within 20% of the contralateral foot while the posterior facet and CC joint had to be congruent with a step-off less than 2 mm. Several functional scores related to foot and ankle pathology were used to evaluate functional outcomes (American Orthopedic Foot and Ankle Score - AOFAS, Lower Extremity Functional Score - LEFS, Olerud and Molander Ankle Score - OMAS, Calcaneal Functional Scoring System - CFSS, Visual Analog Scale for pain – VAS) and were compared between anatomic and nonanatomic DIAFCs using Student's t-test. Demographic data and information about injury severity were collected for each patient. Among the 84 enrolled patients, 6 were excluded while 11 were lost to follow-up. Thirty-nine patients had a nonanatomic reduction while 35 patients had an anatomic reduction (47%). Baseline characteristics were similar in both groups. When we compared the injury severity as defined by the Sanders’ Classification, we did not find a significant difference. In other words, the nonanatomic group did not have a greater proportion of complex fractures. Anatomically reduced DIACFs showed significantly superior results at 12 months for all but one scoring system (mean difference at 12 months: AOFAS 3.97, p = 0.12; LEFS 7.46, p = 0.003; OMAS 13.6, p = 0.002, CFSS 7.5, p = 0.037; VAS −1.53, p = 0.005). Univariate analyses did not show that smoking status, worker's compensation or body mass index were associated with functional outcomes. Moreover, fracture severity could not predict functional outcomes at 12 months. This study showed superior functional outcomes in patients with a DIACF when an anatomic reduction is achieved regardless of the injury severity

Displaced intraarticular calcaneal fractures are debilitating injuries with significant socioeconomic and psychological effects primarily affecting patients in active age between 30 and 50 years. Recently, minimally and less invasive screw fixation techniques have become popular as alternative to locked plating. The aim of this study was to analyze biomechanically in direct comparison the primary stability of 3 different cannulated screw configurations for fixation of Sanders type II-B intraarticular calcaneal fractures. Fifteen fresh-frozen human cadaveric lower limbs were amputated mid-calf and through the Chopart joint. Following, soft tissues at the lateral foot side were removed, whereas the medial side and Achilles tendon were preserved. Reproducible Sanders type II-B intraarticular fracture patterns were created by means of osteotomies. The proximal tibia end and the anterior-inferior aspect of the calcaneus were then embedded in polymethylmethacrylate. Based on bone mineral density measurements, the specimens were randomized to 3 groups for fixation with 3 different screw configurations using two 6.5 mm and two 4.5 mm cannulated screws. In Group 1, two parallel longitudinal screws entered the tuber calcanei above the Achilles tendon insertion and proceeded to the anterior process, and two transverse screws fixed the posterior facet perpendicular to the fracture line. In Group 2, two parallel screws entered the tuber calcanei below the Achilles tendon insertion, aiming at the anterior process, and two transverse screws fixed the posterior facet. In Group 3, two screws were inserted along the bone axis, entering the tuber calcanei above the Achilles tendon insertion and proceeding to the central-inferior part of the anterior process. In addition, one transverse screw was inserted from lateral to medial for fixation of the posterior facet and one oblique screw – inserted from the posterior-plantar part of the tuber calcanei – supported the posterolateral part of the posterior facet. All specimens were tested in simulated midstance position under progressively increasing cyclic loading at 2 Hz. Starting from 200N, the peak load of each cycle increased at a rate of 0.1 N/cycle. Interfragmentary movements were captured by means of optical motion tracking and triggered mediolateral x-rays. Plantar movement, defined as displacement between the anterior process and the tuber calcanei at the most inferior side was biggest in Group 2 and increased significantly over test cycles in all groups (P = 0.001). Cycles to 2 mm plantar movement were significantly higher in both Group 1 (15847 ± 5250) and Group 3 (13323 ± 4363) compared to Group 2 (4875 ± 3480), P = 0.048. Medial gapping after 2500 cycles was significantly bigger in Group 2 versus Group 3, P = 0.024. No intraarticular displacement was observed in any group during testing. From biomechanical perspective, screw configuration implementing one oblique screw seems to provide sufficient hindfoot stability in Sanders Type II-B intraarticular calcaneal fractures under dynamic loading. Posterior facet support by means of buttress or superiorly inserted longitudinal screws results in less plantar movement between the tuber calcanei and anterior fragments. On the other hand, inferiorly inserted longitudinal screws seem to be associated with bigger interfragmentary movements

We scanned 25 left knees in healthy human subjects using MRI. Multiplanar reconstruction software was used to take measurements of the inferior and posterior facets of the femoral condyles and the trochlea. A ‘basic circle’ can be defined which, in the sagittal plane, fits the posterior and inferior facets of the lateral condyle, the posterior facet of the medial condyle and the floor of the groove of the trochlea. It also approximately fits both condyles in the coronal plane (inferior facets) and the axial plane (posterior facets). The circle fitting the inferior facet of the medial condyle in the sagittal plane was consistently 35% larger than the other circles and was termed the ‘medial inferior circle’. There were strong correlations between the radii of the circles, the relative positions of the centres of the condyles, the width of the condyles, the total knee width and skeletal measurements including height. There was poor correlation between the radii of the circles and the position of the trochlea relative to the condyles. In summary, the condyles are approximately spherical except for the inferior facet medially, which has a larger radius in the sagittal plane. The size and position of the condyles are consistent and change with the size of the person. However, the position of the trochlea is variable even though its radius is similar to that of the condyles. This information has implications for understanding anterior knee pain and for the design of knee replacements. Cite this article: Bone Joint J 2014;96-B:1623–30

From a search of MRI reports on knees, 20 patients were identified with evidence of early anteromedial osteoarthritis without any erosion of bone and a control group of patients had an acute rupture of the anterior cruciate ligament. The angle formed between the extension and flexion facets of the tibia, which is known as the extension facet angle, was measured on a sagittal image at the middle of the medial femoral condyle. The mean extension facet angle in the control group was 14° (3° to 25°) and was unrelated to age (Spearman’s rank coefficient, p = 0.30, r = 0.13). The mean extension facet angle in individuals with MRI evidence of early anteromedial osteoarthritis was 19° (13° to 26°, SD 4°). This difference was significant (Mann-Whitney U test, p < 0.001). A wide variation in the extension facet angle was found in the normal control knees and an association between an increased extension facet angle and MRI evidence of early anteromedial osteoarthritis. Although a causal link has not been demonstrated, we postulate that a steeper extension facet angle might increase the duration of loading on the extension facet during the stance phase of gait, and that this might initiate failure of the articular cartilage

We examined the reliability of radiological findings in predicting segmental instability in 112 patients (56 men, 56 women) with a mean age of 66.5 years (27 to 84) who had degenerative disease of the lumbar spine. They underwent intra-operative biomechanical evaluation using a new measurement system. Biomechanical instability was defined as a segment with a neutral zone > 2 mm/N. Risk factor analysis to predict instability was performed on radiographs (range of segmental movement, disc height), MRI (Thompson grade, Modic type), and on the axial CT appearance of the facet (type, opening, vacuum and the presence of osteophytes, subchondral erosion, cysts and sclerosis) using multivariate logistic regression analysis with a forward stepwise procedure. The facet type was classified as sagittally orientated, coronally orientated, anisotropic or wrapped. Stepwise multivariate regression analysis revealed that facet opening was the strongest predictor for instability (odds ratio 5.022, p = 0.009) followed by spondylolisthesis, MRI grade and subchondral sclerosis. Forward stepwise multivariate logistic regression indicated that spondylolisthesis, MRI grade, facet opening and subchondral sclerosis of the facet were risk factors. Symptoms evaluated by the Short-Form 36 and visual analogue scale showed that patients with an unstable segment were in significantly more pain than those without. Furthermore, the surgical procedures determined using the intra-operative measurement system were effective, suggesting that segmental instability influences the symptoms of lumbar degenerative disease

Aims. No randomized comparative study has compared the extensile lateral approach (ELA) and sinus tarsi approach (STA) for Sanders type 2 calcaneal fractures. This randomized comparative study was conducted to confirm whether the STA was prone to fewer wound complications than the ELA. Methods. Between August 2013 and August 2018, 64 patients with Sanders type 2 calcaneus fractures were randomly assigned to receive surgical treatment by the ELA (32 patients) and STA (32 patients). The primary outcome was development of wound complications. The secondary outcomes were postoperative complications, pain scored of a visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, 36-item Short Form health survey, operative duration, subtalar joint range of motion (ROM), Böhler’s angle and calcaneal width, and posterior facet reduction. Results. Although four patients (12.5%) in the ELA groups and none in the STA group experienced complications, the difference was not statistically significant (p = 0.113). VAS and AOFAS score were significantly better in the STA group than in the ELA group at six months (p = 0.017 and p = 0.021), but not at 12 months (p = 0.096 and p = 0.200) after surgery. The operation time was significantly shorter in the STA group than in the ELA group (p < 0.001). The subtalar joint ROM was significantly better in the STA group (p = 0.015). Assessment of the amount of postoperative reduction compared with the uninjured limb showed significant restoration of calcaneal width in the ELA group compared with that in the STA group (p < 0.001). Conclusion. The ELA group showed higher frequency of wound complications than the STA group for Sanders type 2 calcaneal fractures even though this was not statistically significant. Cite this article: Bone Joint J 2021;103-B(2):286–293

Distal radius fractures have an incidence rate of 17.5% among all fractures. Their treatment in case of comminution, commonly managed by volar locking plates, is still challenging. Variable-angle screw technology could counteract these challenges. Additionally, combined volar and dorsal plate fixation is valuable for treatment of complex fractures at the distal radius. Currently, biomechanical investigation of the competency of supplemental dorsal plating is scant. The aim of this study was to investigate the biomechanical competency of double-plated distal radius fractures in comparison to volar locking plate fixation. Complex intra-articular distal radius fractures AO/OTA 23-C 2.1 and C 3.1 were created by means of osteotomies, simulating dorsal defect with comminution of the lunate facet in 30 artificial radii, assigned to 3 study groups with 10 specimens in each. The styloid process of each radius was separated from the shaft and the other articular fragments. In group 1, the lunate facet was divided to 3 equally-sized fragments. In contrast, the lunate in group 2 was split in a smaller dorsal and a larger volar fragment, whereas in group 3 was divided in 2 equal fragments. Following fracture reduction, each specimen was first instrumented with a volar locking plate and non-destructive quasi-static biomechanical testing under axial loading was performed in specimen's inclination of 40° flexion, 40° extension and 0° neutral position. Mediolateral radiographs were taken under 100 N loads in flexion and extension, as well as under 150 N loads in neutral position. Subsequently, all biomechanical tests were repeated after supplemental dorsal locking plate fixation of all specimens. Based on machine and radiographic data, stiffness and angular displacement between the shaft and lunate facet were determined. Stiffness in neutral position (N/mm) without/with dorsal plating was on average 164.3/166, 158.5/222.5 and 181.5/207.6 in groups 1–3. It increased significantly after supplementary dorsal plating in groups 2 and 3. Predominantly, from biomechanical perspective supplemental dorsal locked plating increases fixation stability of unstable distal radius fractures after volar locked plating. However, its effect depends on the fracture pattern at the distal radius

Background. Open subtalar arthrodesis has been associated with a moderate rate of non-union, as high 16.3%, and high rates of infection and nerve injury. Performing this operation arthroscopically serves to limit the disruption to the soft tissue envelope, improve union rates and reduce infection. Our study describes our outcomes and experience of this operation. Method. Retrospective review of all patients who underwent an arthroscopic subtalar arthrodesis between 2023 and 2008. We excluded patients undergoing concurrent adjacent joint arthrodesis. The primary aim was to report on rates of union. Secondary outcomes included reporting on conversion to open procedure, duration of surgery, infection, and iatrogenic injury to surrounding structures. Results. 135 patients were included in the final analysis. 129 patients (95.5%) achieved union. The median time to fusion was 98 days. All cases were performed through sinus tarsi portals. 38 cases were performed with an additional posterolateral portal. Most cases (107/77%) were performed with 2 screws. 3 cases (2.2%) were converted to open procedures. The median tourniquet time was 86 minutes but available in only 88 (65%) cases. There were 4 (2.9%) superficial infections and no deep infections. 1 patient sustained an injury to FHL and there were no reported nerve injuries. Conclusions. At present this is the largest series of arthroscopic subtalar arthrodeses. We demonstrate that this operation can achieve high rates of union with low rates of infection with an equally low likelihood of needing to convert to an open procedure with modest operative times. In our experience the addition of a posterolateral portal does not appear to increase the incidence of nerve injury and aids in the visualisation of all 3 facets

Aim. By gaining insight into the Quality of Life (QoL) status and occurrence of complications, critical facets in the care for patients with Fracture-Related Infection (FRI) can be mitigated and measures can be taken to improve their outcome. Therefore, the aims of this study were to 1) determine the QoL in FRI patients in comparison to non-FRI patients and 2) describe the occurrence of complications in both FRI and non-FRI patients. Method. An ambidirectional cohort study was conducted in a level-1 trauma centre between January 1st 2016 and November 1st 2021. All patients who underwent surgical stabilisation of a long bone fracture were eligible for inclusion. Patients with an Injury Severity Score (ISS) ≥16 or incomplete follow-up were excluded. QoL was assessed through the use of five-level EuroQol five-dimension (EQ-5D-5L) questionnaires twelve months post-injury. Results. A total of 134 patients were included, of whom 38 (28%) FRI patients and 96 (72%) non-FRI patients. In comparison to non-FRI patients, FRI patients scored significantly worse on the QoL assessment regarding the index value (p=0.012) and the domains mobility (p<0.001), usual activities (p=0.010) and pain/discomfort (p=0.009). During the median follow-up of 14.5 months (interquartile range (IQR) 9.5–26.5), 25 FRI patients developed a total of 49 distinctive complications besides FRI. The complications nonunion (18%, n=9/49), infection other than FRI (e.g. line infection, urinary tract infection, pneumonia) (18%, n=9/49) and implant failure (14%, n=7/49) were the most frequently described in the FRI group. Conclusions. Patients who suffered from an FRI have a decreased QoL in comparison to those without an FRI. Moreover, patients with an FRI have a higher rate of additional complications. These findings can help in patient counselling regarding the potential physical and mental consequences of having a complicated course of recovery due to an infection

Introduction. The aetiology of hallux valgus is almost certainly multifactoral. The biomechanics of the first ray is a common factor to most. There is very little literature examining the anatomy of the proximal metatarsal articular surface and its relationship to hallux valgus deformity. Methods. We examined 42 feet from 23 specimens in this anatomical dissection study. Results. This analysis revealed three distinct articular subtypes. Type 1 had one single facet, type 2 had two distinct articular facets, and type 3 had three articular facets one of which was a lateral inferior facet elevated from the first. Type 1 joints occurred exclusively in the hallux valgus specimens, while type 3 joints occurred exclusively in normal specimens. Type 2 joints occurred in both hallux valgus and normal specimens. Another consistent finding in regards to the proximal articular surface of the first metatarsal was the lateral plantar prominence. This prominence possessed its own articular surface in type 3 joints and was significantly flatter in specimens with hallux valgus (p < 0.001) and the angle with the joint was significantly more obtuse (p < 0.001). Conclusions. We believe the size and acute angle of this prominence gives structural mechanical impedance to movement at the tarsometatarsal joint and thus improves the stability

We previously reported that osteoblasts at the curve apex in adolescent idiopathic scoliosis (AIS) exhibit a differential phenotype, compared to non-curve osteoblasts(1). However, the Hueter-Volkmann principle on vertebral body growth in spinal deformities (2) suggests this could be secondary to altered biomechanics. This study examined whether non-curve osteoblasts subjected to mechanical strain resemble the transcriptomic phenotype of curve apex osteoblasts. Facet spinal tissue was collected perioperatively from three sites, (i) the concave and (ii) convex side at the curve apex and (iii) from outside the curve (non-curve) from six AIS female patients (age 13–18 years; NRES 19/WM/0083). Non-curve osteoblasts were subjected to strain using a 4-point bending device. Osteoblast phenotype was determined by RNA sequencing and bioinformatic pathway analysis. RNAseq revealed that curve apex osteoblasts exhibited a differential transcriptome, with 1014 and 1301 differentially expressed genes (DEGs; p<0.05, fold-change >1.5) between convex/non-curve and concave/non-curve sites respectively. Non-curve osteoblasts subjected to strain showed increased protein expression of the mechanoresponsive biomarkers COX2 and C-Fos. Comparing unstimulated vs strain-induced non-curve osteoblasts, 423 DEGs were identified (p<0.05, fold-change >1.5). Of these DEGs, only 5% and 6% were common to the DEGs found at either side of the curve apex, compared to non-curve cells. Bioinformatic analysis of these strain-induced DEGs revealed a different array of canonical signalling pathways and cellular processes, to those significantly affected in cells at the curve apex. Mechanical strain of AIS osteoblasts in vitro did not induce the differential transcriptomic phenotype of AIS osteoblasts at the curve apex

The use of intraoperative navigation and robotic surgery for minimally invasive lumbar fusion has been increasing over the past decade. The aim of this study is to evaluate postoperative clinical outcomes, intraoperative parameters, and accuracy of pedicle screw insertion guided by intraoperative navigation in patients undergoing lumbar interbody fusion for spondylolisthesis. Patients who underwent posterior lumbar fusion interbody using intraoperative 3D navigation since December 2021 were included. Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Short Form Health Survey-36 (SF-36) were assessed preoperatively and postoperatively at 1, 3, and 6 months. Screw placement accuracy, measured by Gertzbein and Robbins classification, and facet joint infringement, measured by Yson classification, were assessed by intraoperative Cone Beam CT scans performed at the end of instrumentation. Finally, operation time, intraoperative blood loss, hospital stay, and screw insertion time were evaluated. This study involved 50 patients with a mean age of 63.7 years. VAS decreased from 65.8±23 to 20±22 (p<.01). ODI decreased from 35.4%±15 to 11.8%±14 (p<.01). An increase of SF-36 from 51.5±14 to 76±13 (p<.01) was demonstrated. The accuracy of “perfect” and “clinically acceptable” pedicle screw fixation was 89.5% and 98.4%, respectively. Regarding facet violation, 96.8% of the screws were at grade 0. Finally, the average screw insertion time was 4.3±2 min, hospital stay was 4.2±0.8 days, operation time was 205±53 min, and blood loss was 169±107 ml. Finally, a statistically significant correlation of operation time with hospital stay, blood loss and placement time per screw was found. We demonstrated excellent results for accuracy of pedicle screw fixation and violation of facet joints. VAS, ODI and SF-36 showed statistically significant improvements from the control at one month after surgery. Navigation with intraoperative 3D images represents an effective system to improve operative performance in the surgical treatment of spondylolisthesis

We dissected 12 fresh-frozen leg specimens to identify the insertional footprint of each fascicle of the Achilles tendon on the calcaneum in relation to their corresponding muscles. A further ten embalmed specimens were examined to confirm an observation on the retrocalcaneal bursa. The superficial part of the insertion of the Achilles tendon is represented by fascicles from the medial head of the gastrocnemius muscle, which is inserted over the entire width of the inferior facet of the calcaneal tuberosity. In three specimens this insertion was in continuity with the plantar fascia in the form of periosteum. The deep part of the insertion of the Achilles tendon is made of fascicles from the soleus tendon, which insert on the medial aspect of the middle facet of the calcaneal tuberosity, while the fascicles of the lateral head of the gastrocnemius tendon insert on the lateral aspect of the middle facet of the calcaneal tuberosity. A bicameral retrocalcaneal bursa was present in 15 of the 22 examined specimens. . This new observation and description of the insertional footprint of the Achilles tendon and the retrocalcaneal bursa may allow a better understanding of the function of each muscular part of the gastrosoleus complex. This may have clinical relevance in the treatment of Achilles tendinopathies. Cite this article: Bone Joint J 2014; 96-B:1344–8

Abstract. Purpose. Recently several authors have suggested a correlation between posterior tibial slope (PTS) and sagittal stability of the knee. However, there is a lack of consensus in the literature relating to measurement, normal values and important values to guide treatment. We performed a systematic literature review looking at PTS and cruciate ligament surgery. Our aim was to define a gold standard measurement technique, determine normal ranges and important values for consideration during cruciate ligament surgery. Methods. Electronic searches of MEDLINE (PubMed), CINAHL, Cochrane, Embase, ScienceDirect, and NICE in June 2020 were completed. Inclusion criteria were original studies in peer-reviewed English language journals. A quality assessment of included studies was completed using the Methodological Index for Non-Randomized Studies (MINORS) Criteria. Results. Two-hundred and twenty-one papers were identified; following exclusions 34 papers were included for data collection. The mean MINORS score for non-comparative studies was 13.8 and for comparative studies 20.4, both indicating fair to good quality studies. A large variation in PTS measurement technique was identified, resulting in a wide range of values reported. In addition, there appears to be significant variation between different races, ages and genders. Conclusion. We demonstrated a lack of consensus in the literature relating to various facets of PTS. Cautiously, we suggest normal ranges of 6–12º using the proximal tibia axis at 5 and 15cms below the joint. Potentially 12º is an important cute-off for slope reducing osteotomy as an adjunct to revision ACL reconstruction

Surgical trainees are finding it increasingly more challenging to meet operative requirements and coupled with the effects of COVID-19, we face a future of insufficiently trained surgeons. As a result, virtual reality (VR) simulator training has become more prevalent and whilst more readily accepted in certain arthroscopic fields, its use in hip arthroscopy (HA) remains novel. This project aimed to validate VR high-fidelity HA simulation and assess its functional use in arthroscopic training. Seventy-two participants were recruited to perform two basic arthroscopic tasks on a VR HA simulator, testing hip anatomy, scope manipulation and triangulation skills. They were stratified into novice (39) and experienced (33) groups based on previous arthroscopy experience. Metric parameters recorded from the simulator were used to assess construct validity. Face validity was evaluated using a Likert-style questionnaire. All recordings were reviewed by 2 HA experts for blinded ASSET score assessment. Experienced participants were significantly faster in completing both tasks compared with novice participants (p<0.001). Experienced participants damaged the acetabular and femoral cartilage significantly less than novice participants (p=0.011) and were found to have significantly reduced path length of both camera and instrument across both tasks (p=0.001, p=0.007), demonstrating significantly greater movement economy. Total ASSET scores were significantly greater in experienced participants compared to novice participants (p=0.041) with excellent correlation between task time, cartilage damage, camera and instrument path length and corresponding ASSET score constituents. 62.5% of experienced participants reported a high degree of realism in all facets of external, technical and haptic experience with 94.4% advising further practice would improve their arthroscopic skills. There was a relative improvement of 43% in skill amongst all participants between task 1 and 2 (p<0.001). This is the largest study to date validating the use of simulation in HA training. These results confirm significant construct and face validity, excellent agreement between objective measures and ASSET scores, significant improvement in skill with continued use and recommend VR simulation to be a valuable asset in HA training for all grades

Introduction. Kinematics post-TKA are complex; component alignment, component geometry and the patient specific musculoskeletal environment contribute towards the kinematic and kinetic outcomes of TKA. Tibial rotation in particular is largely uncontrolled during TKA and affects both tibiofemoral and patellofemoral kinematics. Given the complex nature of post- TKA kinematics, this study sought to characterize the contribution of tibial tray rotation to kinematic outcome variability across three separate knee geometries in a simulated framework. Method. Five 50. th. percentile knees were selected from a database of planned TKAs produced as part of a pre-operative dynamic planning system. Virtual surgery was performed using Stryker (Kalamazoo, MI) Triathlon CR and PS and MatOrtho (Leatherhead, UK) SAIPH knee medially stabilised (MS) components. All components were initially planned in mechanical alignment, with the femoral component neutral to the surgical TEA. Each knee was simulated through a deep knee bend, and the kinematics extracted. The tibial tray rotational alignment was then rotated internally and externally by 5° & 10°. The computational model simulates a patient specific deep knee bend and has been validated against a cadaveric Oxford Knee Rig. Preoperative CT imaging was obtained, landmarking to identify all patient specific axes and ligament attachment sites was performed by pairs of trained biomedical engineers. Ethics for this study is covered by Bellberry Human Research Ethics Committee application number 2012-03-710. Results and Discussion. From the 360 Knee Systems database, 1847 knees were analysed, giving an average coronal alignment of 4.25°±5.66° varus. Five knees were selected with alignments between 4.1° and 4.3° varus. Kinematic outcomes were averaged over the 5 knees. The component geometries resulted in characteristically distinct kinematics, in which femoral rollback was most constrained by the PS components, whereas tibiofemoral axial rotation was most constrained in MS components. Patella lateral shift was comparable amongst all components in extension, medialising in flexion. Patella shift remained more lateral in MS components compared to PS and CR. Average patella lateral shift, medial and lateral facet rollback separated by tibial tray rotation are shown for all component systems in Figure 1. Medial and lateral facet rollback in the PS and CR components are symmetrical and opposite, indicating that with tibial tray rotation, the tibiofemoral articulation point balances between component rotation and neutral alignment, reflecting the restoring force exerted by the simulated collateral ligaments. As such, with higher internal tibial rotation and subsequent lateralisation of the tubercle, patella lateral shift increases. MS medial and lateral facet rollback however are not symmetrical nor opposite, reflecting the chirality of the tibiofemoral articulation. With internal tibial tray rotation, relatively high lateral facet rollback is observed, lateralising the femoral component centre, giving the patella component a relatively more medial position. Conclusions. Component geometry was found here to produce characteristically distinct tibiofemoral and patellofemoral kinematics. Medial stabilised components reported asymmetric kinematic changes, compared to either CR or PS components, in which a higher rate of change was observed for internal tray rotation, indicating that neutral or external rotation of medial stabilised components will result in more predictable kinematic outcomes

Aims. It remains controversial whether patellofemoral joint pathology is a contraindication to lateral unicompartmental knee arthroplasty (UKA). This study aimed to evaluate the effect of preoperative radiological degenerative changes and alignment on patient-reported outcome scores (PROMs) after lateral UKA. Secondarily, the influence of lateral UKA on the alignment of the patellofemoral joint was studied. Methods. A consecutive series of patients who underwent robotic arm-assisted fixed-bearing lateral UKA with at least two-year follow-up were retrospectively reviewed. Radiological evaluation was conducted to obtain a Kellgren Lawrence (KL) grade, an Altman score, and alignment measurements for each knee. Postoperative PROMs were assessed using the Kujala (Anterior Knee Pain Scale) score, Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS JR), and satisfaction levels. Results. A total of 140 knees (130 patients) were identified for analysis. At mean 4.1 years (2.0 to 8.5) follow-up, good to excellent Kujala scores were reported. The presence of mild to moderate preoperative patellofemoral joint osteoarthritis had no impact on these scores (KL grade 0 vs 1 to 3, p = 0.203; grade 0 to 1 vs 2 to 3, p = 0.674). Comparable scores were reported by patients with osteoarthritis (Altman score of ≥ 2) evident on either the medial or lateral patellofemoral joint facet (medial, p = 0.600 and lateral, p = 0.950). Patients with abnormal patellar congruence and tilt angles (≥ 17° and ≥ 14°, respectively) reported good to excellent Kujala scores. Furthermore, lateral UKA resulted in improvements to patellofemoral alignment. Conclusion. This is the first study demonstrating that mild to moderate preoperative radiological degenerative changes and malalignment of the patellofemoral joint are not associated with poor patient-reported outcomes at mid-term follow-up after lateral fixed-bearing UKA. Our data suggest that this may be explained by realignment of the patella and thereby redistribution of loads across the patellofemoral joint. Cite this article: Bone Joint J 2020;102-B(6):727–735

Aims. The aim of this study was to investigate the changes in femoral trochlear morphology following surgical correction of recurrent patellar dislocation associated with trochlear dysplasia in children. Patients and Methods. A total of 23 patients with a mean age of 9.6 years (7 to 11) were included All had bilateral recurrent patellar dislocation associated with femoral trochlear dysplasia. The knee with traumatic dislocation at the time of presentation or that had dislocated most frequently was treated with medial patellar retinacular plasty (Group S). The contralateral knee served as a control and was treated conservatively (Group C). All patients were treated between October 2008 and August 2013. The mean follow-up was 48.7 months (43 to 56). Axial CT scans were undertaken in all patients to assess the trochlear morphological characteristics on a particular axial image which was established at the point with the greatest epicondylar width based on measurements preoperatively and at the final follow-up. Results. Preoperatively, there were no statistically significant differences between the trochlear morphology in the two groups (sulcus angle, p 0.852; trochlear groove depth, p 0.885; lateral trochlear inclination, p 0.676; lateral-to-medial facet ratio, p 0.468; lateral condylar height, p 0.899; medial condylar height, p 0.816). Many radiological parameters of trochlear morphology were significantly different between the two groups at the final follow-up, including well-known parameters, such as the mean sulcus angle (Group S, 146.27° (. sd. 7.18); Group C, 160.61° (. sd. 9.29); p < 0.001), the mean trochlear groove depth (Group S, 6.25 mm (. sd. 0.41); Group C, 3.48 mm (. sd. 0.65); p < 0.001) and the mean lateral trochlear inclination (Group S, 20.99° (. sd. 3.87); Group C, 12.18° (. sd. 1.85); p < 0.001). Lesser known parameters such as the ratio of the lateral to medial trochlear length (Group S, 1.46 (. sd. 0.19); Group C, 2.14 (. sd. 0.42); p < 0.001), which is a measurement of facet asymmetry, and the lateral and medial condylar height were also significantly different between the two groups (p < 0.001). Conclusion. The femoral trochlear morphology can be improved by early (before epiphyseal closure) surgical correction in children with recurrent patellar dislocation associated with femoral trochlear dysplasia. Cite this article: Bone Joint J 2018;100-B:811–21

Treatment of comminuted intraarticular calcaneal fractures remains controversial and challenging. Anatomic reduction with stable fixation has demonstrated better outcomes than nonoperative treatment of displaced intraarticular fractures involving the posterior facet and anterior calcaneocuboid joint (CCJ) articulating surface of the calcaneus. The aim of this study was to investigate the biomechanical performance of three different methods for fixation of comminuted intraarticular calcaneal fractures. Comminuted calcaneal fractures, including Sanders III-AB fracture of the posterior facet and Kinner II-B fracture of the CCJ articulating calcaneal surface, were simulated in 18 fresh-frozen human cadaveric lower legs by means of osteotomies. The ankle joint, medial soft tissues and midtarsal bones along with the ligaments were preserved. The specimens were randomized according to their bone mineral density to 3 groups for fixation with either (1) 2.7 mm variable-angle locking anterolateral calcaneal plate in combination with one 4.5 mm and one 6.5 mm cannulated screw (Group 1), (2) 2.7 mm variable-angle locking lateral calcaneal plate (Group 2), or (3) interlocking calcaneal nail with 3.5 mm screws in combination with 3 separate 4.0 mm cannulated screws (Group 3). All specimens were biomechanically tested until failure under axial loading with the foot in simulated midstance position. Each test commenced with an initial quasi-static compression ramp from 50 N to 200 N, followed by progressively increasing cyclic loading at 2Hz. Starting from 200 N, the peak load of each cycle increased at a rate of 0.2 N/cycle. Interfragmentary movements were captured by means of optical motion tracking. In addition, mediolateral X-rays were taken every 250 cycles with a triggered C-arm. Varus deformation between the tuber calcanei and lateral calcaneal fragments, plantar gapping between the anterior process and tuber fragments, displacement at the plantar aspect of the CCJ articular calcaneal surface, and Böhler angle were evaluated. Varus deformation of 10° was reached at significantly lower number of cycles in Group 2 compared to Group 1 and Group 3 (P ≤ 0.017). Both cycles to 10° plantar gapping and 2 mm displacement at the CCJ articular calcaneal surface revealed no significant differences between the groups (P ≥ 0.773). Böhler angle after 5000 cycles (1200 N peak load) had significantly bigger decrease in Group 2 compared to both other groups (P ≤ 0.020). From biomechanical perspective, treatment of comminuted intraarticular calcaneal fractures using variable-angle locked plate with additional longitudinal screws or interlocked nail in combination with separate transversal screws seems to provide superior stability as opposed to variable-angle locked plating only

BACKGROUND. Conventional TKA surgery attempts to restore patients to a neutral alignment, and devices are designed with this in mind. Neutral alignment may not be natural for many patients, and may cause dissatisfaction [1]. To solve this, kinematical alignment (KA) attempts to restore the native pre-arthritic joint-line of the knee, with the goal of improving knee kinematics and therefore patient's function and satisfaction [1]. Proper prosthetic trochlea alignment is important to prevent patella complications such as instability or loosening. However, available TKA components have been designed for mechanical implantation, and concerns remain relating the orientation of the prosthetic trochlea when implants are kinematically positioned. The goal of this study is to investigate how a currently available femoral component restores the native trochlear geometry of healthy knees when virtually placed in kinematic alignment. METHODS. The healthy knee OAI (Osteoarthritis Initiative) MRI dataset was used. 36 MRI scans of healthy knees were segmented to produce models of the bone and cartilage surfaces of the distal femur. A set of commercially available femoral components was laser scanned. Custom 3D planning software aligned these components with the anatomical models: distal and posterior condyle surfaces of implants were coincident with distal and posterior condyle surfaces of the cartilage; the anterior flange of the implant sat on the anterior cortex; the largest implant that fitted with minimal overhang was used, performing ‘virtual surgery’ on healthy subjects. Software developed in-house fitted circles to the deepest points in the trochlear grooves of the implant and the cartilage. The centre of the cartilage trochlear circle was found and planes, rotated from horizontal (0%, approximately cutting through the proximal trochlea) through to vertical (100%, cutting through the distal trochlea) rotated around this, with the axis of rotation parallel to the flexion facet axis. These planes cut through the trochlea allowing comparison of cartilage and implant surfaces at 1 degree increments - (fig.1). Trochlear groove geometry was quantified with (1) groove radial distance from centre of rotation cylinder (2) medial facet radial distance (3) lateral facet radial distance and (4) sulcus angle, along the length of the trochlea. Data were normalised to the mean trochlear radius. The orientation of the groove was measured in the coronal and axial plane relative to the flexion facet axis. Inter- and intra-observer reliability was measured. RESULTS. In the coronal plane, the implant trochlear groove was oriented a mean of 8.7° more valgus (p<0.001) than the normal trochlea. The lateral facet was understuffed most at the proximal groove between 0–60% by a mean of 5.3 mm (p<0.001). The medial facet was understuffed by a mean of 4.4 mm between 0–60% (p<0.001) - (fig.2). CONCLUSIONS. Despite attempts to design femoral components with a more anatomical trochlea, there is significant understuffing of the trochlea, which could lead to reduced extensor moment of the quadriceps and contribute to patient dissatisfaction

Aim:. The purpose of this study was to identify factors (radiographic and MRI) which may be important in determining whether a degenerative spondylolisthesis at L4/5 is mobile. Method:. We identified 60 consecutive patients with a degenerative spondylolisthesis(DS) at L4/5 and reviewed their imaging. Patients were separated into groups on the basis of whether the DS was mobile (group A) or non-mobile (Group B) when comparing the upright plain lumbar radiograph to the supine MRI. We assessed the lumbar lordosis, pelvic incidence, sacral slope, pelvic tilt, grade of the slip, facet angles at L4/5, facet tropism, facet effusion size, facet degenerative score (cartilage and sclerosis values) and disc degenerative score (Pfirrmann) at L4/5. Results:. There were 40 patients in group A and 20 in group B. Mean age for group A was 69.2 years and for group B was 66.2 years. The difference was not significant (p-0.27; 95% CI 2.5–8.7). No significant differences were found between groups for pelvic incidence (p-0.75; 95% CI 4.6–6.3), pelvic tilt (p-0.62; 95% CI 3.2–5.3), sacral slope (p-0.51; 95% CI 3.2–6.5), lumbar lordosis (p-0.46; 95% CI 9.5–4.3), degree of facet tropism (p-0.4) and magnitude of the facet effusions (p-0.1). Facet angle differences between groups approached significance (p-0.058; 95% CI 0.1–6.7). Significant differences between groups were found in cartilage degenerative score (p-0.002), facet sclerosis grade (p-0.00) and disc degenerative score (p-0.00). In group B 10 out of 20 (50%) reduced fully and were not apparent on the MRI only. Conclusions:. Sagittal pelvic parameters do not play a significant role in differentiating between mobile and non-mobile DS at L4/5. Mobile DS tends to be associated with more sagittally orientated facets, lower Pfirmann grade, lower facet cartilage and sclerosis degenerative scores. Standing plain lumbar radiographs are essential in all patients over the age of 40 years in order not to miss up to 17% of DS at L4/5. Conflict Of Interest Statement: No conflict of interest

Conventional TKA surgery attempts to restore patients to a neutral alignment, and devices are designed with this in mind. Neutral alignment may not be natural for many patients, and may cause dissatisfaction. To solve this, kinematical alignment (KA) attempts to restore the native pre-arthritic joint-line of the knee, with the goal of improving knee kinematics and therefore patient's function and satisfaction. Proper prosthetic trochlea alignment is important to prevent patella complications such as instability or loosening. However, available TKA components have been designed for mechanical implantation, and concerns remain relating the orientation of the prosthetic trochlea when implants are kinematically positioned. The goal of this study is to investigate how a currently available femoral component restores the native trochlear geometry of healthy knees when virtually placed in kinematic alignment. The healthy knee OAI (Osteoarthritis Initiative) MRI dataset was used. 36 MRI scans of healthy knees were segmented to produce models of the bone and cartilage surfaces of the distal femur. A set of commercially available femoral components was laser scanned. Custom 3D planning software aligned these components with the anatomical models: distal and posterior condyle surfaces of implants were coincident with distal and posterior condyle surfaces of the cartilage; the anterior flange of the implant sat on the anterior cortex; the largest implant that fitted with minimal overhang was used, performing ‘virtual surgery’ on healthy subjects. Software developed in-house fitted circles to the deepest points in the trochlear grooves of the implant and the cartilage. The centre of the cartilage trochlear circle was found and planes, rotated from horizontal (0%, approximately cutting through the proximal trochlea) through to vertical (100%, cutting through the distal trochlea) rotated around this, with the axis of rotation parallel to the flexion facet axis. These planes cut through the trochlea allowing comparison of cartilage and implant surfaces at 1 degree increments. Trochlear groove geometry was quantified with (1) groove radial distance from centre of rotation cylinder (2) medial facet radial distance (3) lateral facet radial distance and (4) sulcus angle, along the length of the trochlea. Data were normalised to the mean trochlear radius. The orientation of the groove was measured in the coronal and axial plane relative to the flexion facet axis. Inter- and intra-observer reliability was measured. In the coronal plane, the implant trochlear groove was oriented a mean of 8.7° more valgus (p<0.001) than the normal trochlea. The lateral facet was understuffed most at the proximal groove between 0–60% by a mean of 5.3 mm (p<0.001). The medial facet was understuffed by a mean of 4.4 mm between 0–60% (p<0.001). Despite attempts to design femoral components with a more anatomical trochlea, there is significant understuffing of the trochlea, which could lead to reduced extensor moment of the quadriceps and contribute to patient dissatisfaction

Abstract. Background. Conventional TKR aims for neutral mechanical alignment which may result in a smaller lateral distal femoral condyle resection than the implant thickness. We aim to explore the mismatch between implant thickness and bone resection using 3D planning software used for Patient Specific Instrumentation (PSI) TKR. Methods. This is a retrospective anatomical study from pre-operative MRI 3D models for PSI TKR. Cartilage mapping allowed us to recreate the native anatomy, enabling us to quantify the mismatch between the distal lateral femoral condyle resection and the implant thickness. Results. We modelled 292 knees from PSI TKR performed between 2012 and 2015. There were 225 varus knees and 67 valgus knees, with mean supine hip-knee-angle of 5.6±3.1 degrees and 3.6±4.6 degrees, respectively. In varus knees, the mean cartilage loss from medial and lateral femoral condyle was 2.3±0.7mm and 1.1±0.8mm respectively; the mean overstuffing of the lateral condyle 1.9±2.2mm. In valgus knees, the mean cartilage loss from medial and lateral condyle was 1.4±0.8mm and 1.5±0.9mm respectively; the mean overstuffing of the lateral condyle was 4.1±1.9mm. Conclusions. Neutral alignment TKR often results in overstuffing of the lateral condyle. This may increase the patello-femoral pressure at the lateral facet in flexion. Anterior knee pain may be persistent even after patellar resurfacing due to tight lateral retinacular structures. An alternative method of alignment such as anatomic alignment may minimise this problem

Patellofemoral joint degeneration is often considered a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on the intra-operative status of the patellofemoral joint in 824 knees in 793 consecutive patients who underwent Oxford unicondylar knee replacement for anteromedial osteoarthritis. All operations were performed between January 1998 and September 2005. A five-point grading system classified degeneration of the patellofemoral joint from none to full-thickness cartilage loss. A subclassification of the presence or absence of any full-thickness cartilage loss was subsequently performed to test selected hypotheses. Outcome was evaluated independently by physiotherapists using the Oxford and the American Knee Society Scores with a minimum follow-up of one year. Full-thickness cartilage loss on the trochlear surface was observed in 100 of 785 knees (13%), on the medial facet of the patella in 69 of 782 knees (9%) and on the lateral facet in 29 of 784 knees (4%). Full-thickness cartilage loss at any location was seen in 128 knees (16%) and did not produce a significantly worse outcome than those with a normal or near-normal joint surface. The severity of the degeneration at any of the intra-articular locations also had no influence on outcome. We concluded that, provided there is not bone loss and grooving of the lateral facet, damage to the articular cartilage of the patellofemoral joint to the extent of full-thickness cartilage loss is not a contraindication to the Oxford mobile-bearing unicompartmental knee replacement

We retrospectively analysed the MR scans of 25 patients with patellofemoral dysplasia and ten control subjects, to assess whether there was any change in the morphology of the patella along its vertical length. Ratios were calculated comparing the size of the cartilaginous and subchondral osseous surfaces of the lateral and medial facets. We also classified the morphology using the scoring systems of Baumgartl and Wiberg. There were 18 females and seven males with a mean age of 20.2 years (10 to 29) with dysplasia and two females and eight males with a mean age of 20.4 years (10 to 29) in the control group. In the patient group there was a significant difference in morphology from proximal to distal for the cartilaginous (Analysis of variance (ANOVA) p = 0.004) and subchondral osseous surfaces (ANOVA, p = 0.002). In the control group there was no significant difference for either the cartilaginous (ANOVA, p = 0.391) or the subchondral osseous surface (ANOVA, p = 0.526). Our study has shown that in the dysplastic patellofemoral articulation the medial facet of the patella becomes smaller in relation to the lateral facet from proximal to distal. MRI is needed to define clearly the cartilaginous and osseous morphology of the patella before surgery is considered for patients with patellofemoral dysplasia

Introduction: With increasing availability of CT scans their use in the investigation of the subtalar joint increases, whilst we continue to use plain x-ray. Using a standardised reporting protocol, we graded x-rays and CT scans to compare the diagnosis made using each modality. Materials and Methods: An atlas and reporting system of the subtalar joint was designed using a modification of Kellgren and Lawrence’s system. 50 consecutive CT scans of the subtalar joint were identified and saved along with paired plain x-rays of the foot and ankle. All investigations were anonymised. Scans were excluded if there were no plain films or there was evidence of previous trauma. Orthopaedic surgeons were asked to report on the 50 CT scans and 50 plain radiographs using the reporting protocol, commenting on two components for each investigation; the anterior and middle facets and the posterior facet of the subtalar joint. Results: In 33% of cases the facets of the subtalar joint could not be appreciated from the plain x-rays. The difference between the modalities in reported grade of degeneration of the anterior and middle facets of the subtalar joint was statistically significant (p= 0.014) but not for the posterior facet (0.726). When looking at the Spearman correlation coefficient, the anterior and middle facets had no correlation (r = − 0.067) although the posterior facet did (r = 0.029). Discussion: When looking at the posterior facet of the subtalar joint plain x-rays and CT scans give comparable results. When looking at the anterior and middle facets the information gained from the plain x-rays bears no resemblance to that gained from the CT scans. Conclusion: The plain x-ray is an inaccurate, unreliable method of investigating degenerate pathology of the subtalar joint and should be superseded, and perhaps replaced, by the CT scan

Background. NICE guidance suggests that caudal epidural injections of steroid and local anaesthetic may be considered for acute and severe sciatica, however studies have demonstrated limited long-term benefit and impact on future surgery. This study aimed to investigate the use of caudal epidural injections in a district general hospital setting and the rate of subsequent operation. Methods. All patients undergoing caudal epidural injection between 1. st. January and 30. th. June 2015 were included. Records were reviewed to obtain diagnosis, pre- and post-epidural clinical findings, prior interventions, and subsequent operations. Results. A total of 141 patients underwent a caudal epidural, with a median age of 63 (18 – 90). 37 patients went on to surgical intervention within 3 years, resulting in a conversion rate of 26.1%. Amongst those not requiring surgery, 59 (56.19%) had disc herniation, 42 (40%) stenosis, 4 spondylolisthesis, and 1 a facet cyst. Pre-operatively 63.81% reported back pain and 93.33% sciatica. 39.05% of patients had sensorimotor changes. Post-operatively, 27.62% reported an improvement in their back pain, compared to 62.86% reporting improved leg pain. 36.59% of those with sensorimotor changes reported improvement. 32 later had a further caudal epidural or foraminal block, and 25 had facet and sacroiliac joint injections. Amongst those requiring surgery, 21 (56.76%) had disc herniation, 15 (40.54%) stenosis, and 1 spondylolisthesis (2.7%). Conclusion. In our series, approximately three quarters of patients undergoing caudal epidural injection did not subsequently require surgery. Lumbosacral radicular symptoms improved in two thirds, however the epidural was less effective at treating back pain. No conflicts of interest. No funding obtained

Introduction. Tibial patho-morphology has been described as a factor that predisposes to medial compartment osteoarthritis of the knee in 2D analysis. The aim of this study was to investigate whether the morphology of normal and pre-OA medial compartments are really different in 3 dimensions. Method. A total of 20 normal (group A) and 20 pre-OA knees (group B) were included. Group A consisted of contra-lateral knees of young patients awaiting hip surgery and group B of asymptomatic contra-lateral knees of patients awaiting unicompartmental knee arthroplasty (UKA). Using 3D reconstructions from CT scans, femurs were aligned to the transcondylar and anatomical axes. The medial femoral extension facet was modelled as a sphere. Its radius and the offsets between its centre and the medial flexion facet centre were measured. The tibias were aligned to a flat portion of the flexion facet (flexion facet plane. A model of analysis was developed by rotating several increments towards and away from the midline to obtain several sagittal section images. For each sagittal section the extension facet angle (EFA), its length, and the submeniscal plane angle and length were analysed. Results. The medial femoral extension facet was larger and more offset in pre-OA knees (radius 43 vs 40 mm). The tibial extension facets appeared similar. The EFA varied considerably across the anterior face of the medial plateau (10.3. o. –18.8. o. ). The submeniscal plane was on average horizontally inclined (median 0. o. , range -15–14. o. ) and formed a crescent shape anteriorly. There was no significant difference in tibial measured parameters between normal and pre-OA tibias (p>0.05). The method showed good reproducibility (ICC value>0.9). Discussion. We have found evidence of a predisposing pathomorphology to medial OA, but in the femoral condyle, not the tibia. There is an enlarged extension facet on the medial femoral condyle in the pre-OA knees. There was no significant difference in the geometry of the medial tibial plateau

Endoscopic spine surgery is a promising and minimally invasive technique for the treatment of disc herniation and spinal stenosis. However, the literature on the outcome of interlaminar endoscopic decompression (IED) versus conventional microsurgical technique (CMT) in patients with lumbar spinal stenosis is scarce. We analyzed 88 patients (IED: 36/88, 40.9%; CMT: 52/88, 59.1%) presenting with lumbar central spinal stenosis between 2018–2020. Surgery-related (operation time, complications, time to hospital release (THR), ASA score, C-reactive protein (CRP), white blood cell count (WBC), side (unilateral/bilateral), patient-reported (ODI, NRS (leg-, back pain), eQ5D, COMI), and radiological (preoperative dural sack cross-sectional area (DSCA), Shizas score (SC), left (LRH) and right (RRH) lateral recess heights, left (LFA) and right (RFA) facet angle) parameters were extracted. Complication (most often re-stenosis due to hematoma and/or residual sensorimotor deficits) rates were higher in the endoscopic (38.9%) than microsurgical (13.5%) treatment group (p<0.01). Age, THR, SC, CRP, and DSCA revealed significant correlations with 3 weeks and 1 year postoperatively evaluated ODI, COMI, eQ5D, NRS leg, or NRS back values in our cohort. We did not observe significant differences in the endoscopic versus microsurgical group for the patient-reported outcomes. Age, THR, SC, CRP, and DSCA revealed significant correlations with patient-centered outcomes and should be considered in future studies. Endoscopic treatment of lumbar spinal stenosis was similarly successful as the conventional microsurgical approach, although it was associated with higher complication rates in our single-center study experience. This was probably because of the surgeons' lack of experience with this method and the resulting different learning curve compared with the conventional technique

Trochlear geometry of modern femoral implants is designed for mechanical alignment (MA) technique for TKA. The biomechanical goal is to create a proximalised and more valgus trochlea to better capture the patella and optimize tracking. In contrast, Kinematic alignment (KA) technique for TKA respects the integrity of the soft tissue envelope and therefore aims to restore native articular surfaces, either femoro-tibial or femoro-patellar. Consequently, it is possible that current implant designs are not suitable for restoring patient specific trochlea anatomy when they are implanted using the kinematic technique, this could cause patellar complications, either anterior knee pain, instability or accelerated wear or loosening. The aim of our study is therefore to explore the extent to which native trochlear geometry is restored when the Persona. ®. implant (Zimmer, Warsaw, USA) is kinematically aligned. A retrospective study of a cohort of 15 patients with KA-TKA was performed with the Persona. ®. prosthesis (Zimmer, Warsaw, USA). Preoperative knee MRIs and postoperative knee CTs were segmented to create 3D femoral models. MRI and CT segmentation used Materialise Mimics and Acrobot Modeller software, respectively. Persona. ®. implants were laser scanned to generate 3D implant models. Those implant models have been overlaid on the 3D femoral implant model (generated via segmentation of postoperative CTs) to replicate, in silico, the alignment of the implant on the post-operative bone and to reproduce in the computer models the features of the implant lost due to CT metal artefacts. 3D models generated from post-operative CT and pre-operative MRI were registered to the same coordinate geometry. A custom written planner was used to align the implant, as located on the CT, onto the pre-operative MRI based model. In house software enabled a comparison of trochlea parameters between the native trochlea and the performed prosthetic trochlea. Parameters assessed included 3D trochlear axis and anteroposterior offset from medial facet, central groove, and lateral facet. Sulcus angle at 30% and 40% flexion was also measured. Inter and intra observer measurement variabilities have been assessed. Varus-valgus rotation between the native and prosthetic trochleae was significantly different (p<0.001), with the prosthetic trochlear groove being on average 7.9 degrees more valgus. Medial and lateral facets and trochlear groove were significantly understuffed (3 to 6mm) postoperatively in the proximal two thirds of the trochlear, with greatest understuffing for the lateral facet (p<0.05). The mean medio-lateral translation and internal-external rotation of the groove and the sulcus angle showed no statistical differences, pre and postoperatively. Kinematic alignment of Persona. ®. implants poorly restores native trochlear geometry. Its clinical impact remains to be defined

BACKGROUND. Trochlear geometry of modern femoral implants is designed for the mechanical alignment (MA) technique for Total Knee Arthroplasty (TKA). The biomechanical goal is to create a proximalised and more valgus trochlea to better capture the patella and optimize tracking. In contrast, Kinematic alignment (KA) technique for TKA respects the integrity of the soft tissue envelope and therefore aims to restore native articular surfaces, either femoro-tibial or femoro-patellar. Consequently, it is possible that current implant designs are not suitable for restoring patient specific trochlea anatomy when they are implanted using the kinematic technique. This could cause patellar complications, either anterior knee pain, instability or accelerated wear or loosening. The aim of our study is therefore to explore the extent to which native trochlear geometry is restored when the Persona. ®. implant (Zimmer, Warsaw, USA) is kinematically aligned. METHODS. A retrospective study of a cohort of 15 patients with KA-TKA was performed with the Persona. ®. prosthesis (Zimmer, Warsaw, USA). Preoperative knee MRIs and postoperative knee CTs were segmented to create 3D femoral models. MRI and CT segmentation used Materialise Mimics® and Acrobot Modeller® software, respectively. Persona. ®. implants were laser-scanned to generate 3D implant models. Those implant models have been overlaid on the 3D femoral implant model (generated via segmentation of postoperative CTs) to replicate, in silico, the alignment of the implant on the post-operative bone and to reproduce in the computer models the features of the implant lost due to CT metal artefacts. 3D models generated from post-operative CT and pre-operative MRI were registered to the same coordinate geometry. A custom written planner was used to align the implant, as located on the CT, onto the pre-operative MRI based model (figure 1). In house software enabled a comparison of trochlea parameters between the native trochlea and the performed prosthetic trochlea (figure 2). Parameters assessed included 3D trochlear axis and anteroposterior offset from medial facet, central groove, and lateral facet. Sulcus angle at 30% and 40% flexion was also measured. Inter and intra observer measurement variabilities have been assessed. RESULTS. Varus-valgus rotation between the native and prosthetic trochleae was significantly different (p<0.001), with the prosthetic trochlear groove being on average 7.9 degrees more valgus. Medial and lateral facets and trochlear groove were significantly understuffed (3 to 6mm) postoperatively in the proximal two thirds of the trochlear, with greatest understuffing for the lateral facet (p<0.05). The mean medio-lateral translation and internal-external rotation of the groove and the sulcus angle showed no statistical differences, pre and postoperatively (figure 3). CONCLUSION. Kinematic alignment of Persona. ®. implants poorly restores native trochlear geometry. The clinical impact of this finding remains to be defined. For figures/tables, please contact authors directly.

Purpose: Unrepairable fractures of the radial head are often treated with radial head arthroplasty. Insertion of a radial head prosthesis that is too thick, or overstuffed, is believed to be a common complication that may result in pain, arthrosis, capitellar wear and decreased elbow range of motion. The purpose of this study was to develop guidelines for determining the appropriate thickness of radial head implants. We hypothesized that. radiographic incongruity of the medial facet of the ulnohumeral joint and that. the macroscopic presence of a gap in the lateral facet of the ulnohumeral joint correlate with radial head overstuffing. Method: Six human cadaveric upper extremities were used to evaluate the clinical and radiographic effects of overstuffing of a radial head arthroplasty. Each specimen received an anatomic radial head replacement and then underwent overstuffing with +2 mm, +4 mm, +6 mm and +8 mm lengths. Gross lateral ulnohumeral joint spaces were measured, and anteroposterior radiographs were taken of the elbow from which radiographic medial and lateral ulnohumeral joint spaces were measured. Results: Intraoperative gapping of the lateral ulnohumeral facet was shown to be highly reliable for detecting radial head overstuffing, increasing from a mean of 0.0 mm at standard length to 1.0 mm with 2 mm overstuffing (p < 0.05). Radiographically, the congruity of the lateral ulnohumeral facet was significantly different with 2 mm of overstuffing as compared to the anatomic length (p < 0.05). The congruity of the medial ulnohumeral facet only became significantly different with +6 mm of overstuffing as compared to the anatomic length (p < 0.05). Conclusion: Radiographic incongruity of the medial facet of the ulnohumeral joint was an unreliable indicator of radial head overstuffing. Radiographic gapping of the lateral ulnohumeral facet demonstrated sufficient sensitivity to diagnose radial head overstuffing when compare to the standard length implant radiographs. Visual gapping of the lateral ulnohumeral facet on the cadaver specimens reliably indicated radial head overstuffing and should be a useful anatomic feature to assess intraoperatively

Are there any patho-anatomical features that might predispose to primary knee OA? We investigated the 3D geometry of the load bearing zones of both distal femur and proximal tibias, in varus, straight and valgus knees. We then correlated these findings with the location of wear patches measured intra-operatively. Patients presenting with knee pain were recruited following ethics approval and consent. Hips, knees and ankles were CT-ed. Straight and Rosenburg weight bearing X-Rays were obtained. Excluded were: Ahlbäck grade “>1”, previous fractures, bone surgery, deformities, and any known secondary causes of OA. 72 knees were eligible. 3D models were constructed using Mimics (Materialise Inc, Belgium) and femurs oriented to a standard reference frame. Femoral condyle Extension Facets (EF) were outlined with the aid of gaussian curvature analysis, then best-fit spheres attached to the Extension, as well as Flexion Facets(FF). Resected tibial plateaus from surgery were collected and photographed, and Matlab combined the average tibia plateau wear pattern. Of the 72 knees (N=72), the mean age was 58, SD=11. 38 were male and 34 female. The average hip-knee-ankle (HKA) angle was 1° varus (SD=4°). Knees were assigned into three groups: valgus, straight or varus based on HKA angle. Root Mean Square (RMS) errors of the medial and lateral extension spheres were 0.4mm and 0.2mm respectively. EF sphere radii measurements were validated with Bland-Altman Plots showing good intra- and interobserver reliability (+/− 1.96 SD). The radii (mm) of the extension spheres were standardised to the medial FF sphere. Radii for the standardised medial EF sphere were as follows; Valgus (M=44.74mm, SD=7.89, n=11), Straight (M=44.63mm, SD=7.23, n=38), Varus (M=50.46mm, SD=8.14, n=23). Ratios of the Medial: Lateral EF Spheres were calculated for the three groups: Valgus (M=1.35, SD=.25, n=11), Straight (M=1.38, SD=.23, n=38), Varus (M=1.6, SD=.38, n=23). Data was analysed with a MANOVA, ANOVA and Fisher's pairwise LSD in SPSS ver 22, reducing the chance of type 1 error. The varus knees extension facets were significantly flatter with a larger radius than the straight or valgus group (p=0.004 and p=0.033) respectively. In the axial view, the medial extension facet centers appear to overlie the tibial wear patch exactly, commonly in the antero-medial aspect of the medial tibial plateau. For the first time, we have characterised the extension facets of the femoral condyles reliably. Varus knees have a flatter medial EF even before the onset of bony attrition. A flatter EF might lead to menisci extrusion in full extension, and early menisci failure. In addition, the spherical centre of the EF exactly overlies the wear patch on the antero-medial portion of the tibia plateau, suggesting that a flatter medial extension facet may be causally related to the generation of early primary OA in varus knees

The aim of the study was to assess the safety of a novel anatomical landmark in the placement of thoracic pedicle screws. It is our clinical observation that the sagittal plane of the screw trajectory is perpendicular to the plane of the superior articular facet, when the entry point is in the lateral half of the articular surface of the corresponding superior facet. Using SECTRA software on a PACS digital imaging system, morphometric analysis was performed on thoracic vertebrae imaged using computed tomography (CT). For inclusion, the scan had to have no reported bony abnormality. It was determined whether a trajectory as described at 90 degrees to the articular facet, with an entry point just caudal to the lateral half of the facet to a depth of 25mm would breach either the medial wall of the pedicle or lateral vertebral body wall anterior to the costovertebral facet. Sixty-two CT scans (744 segments, 1488 pedicle-facet complexes) were reviewed. 1154 complexes were suitable for full analysis. Exclusions were due to the lumbarisation of the T12 facet joints (62) or inability to clearly define the facet surface due to the plane of the CT slice (272). Of 1154 entry points assessed, 1154 (100%) were safe to be entered at 90 degrees to a depth of at least 25mm. We have demonstrated the safety and reliability of a novel anatomical landmark in normal thoracic pedicles. We believe this will improve sagittal plane alignment and reduce further the risk of medial pedicle breach

Aims. To develop a core outcome set of measurements from postoperative radiographs that can be used to assess technical skill in performing dynamic hip screw (DHS) and hemiarthroplasty, and to validate these against Van der Vleuten’s criteria for effective assessment. Methods. A Delphi exercise was undertaken at a regional major trauma centre to identify candidate measurement items. The feasibility of taking these measurements was tested by two of the authors (HKJ, GTRP). Validity and reliability were examined using the radiographs of operations performed by orthopaedic resident participants (n = 28) of a multicentre randomized controlled educational trial (ISRCTN20431944). Trainees were divided into novice and intermediate groups, defined as having performed < ten or ≥ ten cases each for DHS and hemiarthroplasty at baseline. The procedure-based assessment (PBA) global rating score was assumed as the gold standard assessment for the purposes of concurrent validity. Intra- and inter-rater reliability testing were performed on a random subset of 25 cases. Results. In total, 327 DHS and 248 hemiarthroplasty procedures were performed by 28 postgraduate year (PGY) 3 to 5 orthopaedic trainees during the 2014 to 2015 surgical training year at nine NHS hospitals in the West Midlands, UK. Overall, 109 PBAs were completed for DHS and 80 for hemiarthroplasty. Expert consensus identified four ‘final product analysis’ (FPA) radiological parameters of technical success for DHS: tip-apex distance (TAD); lag screw position in the femoral head; flushness of the plate against the lateral femoral cortex; and eight-cortex hold of the plate screws. Three parameters were identified for hemiarthroplasty: leg length discrepancy; femoral stem alignment; and femoral offset. Face validity, content validity, and feasibility were excellent. For all measurements, performance was better in the intermediate compared with the novice group, and this was statistically significant for TAD (p < 0.001) and femoral stem alignment (p = 0.023). Concurrent validity was poor when measured against global PBA score. This may be explained by the fact that they are measuring difference facets of competence. Intra-and inter-rater reliability were excellent for TAD, moderate for lag screw position (DHS), and moderate for leg length discrepancy (hemiarthroplasty). Use of a large multicentre dataset suggests good generalizability of the results to other settings. Assessment using FPA was time- and cost-effective compared with PBA. Conclusion. Final product analysis using post-implantation radiographs to measure technical skill in hip fracture surgery is feasible, valid, reliable, and cost-effective. It can complement traditional workplace-based assessment for measuring performance in the real-world operating room . It may have particular utility in competency-based training frameworks and for assessing skill transfer from the simulated to live operating theatre. Cite this article: Bone Joint Open 2020;1-9:594–604

To investigate whether there are different patterns of patellar degeneration, 123 consecutive knee arthroplasties were investigated. Knees on which previous patellar surgery or osteotomies had been done were excluded. Areas of grade-III or more degeneration of the patella and femoral condyle were recorded. The femur was divided into three condyles and nine areas. The patella was divided into three facets and nine areas. In 74 (60%) of the knees, patellar degeneration was less than grade III. In 49 (40%) knees, patellar degeneration was grade III or more. In these 49 knees, there were 122 lesions in the nine areas of the femur and 77 lesions in the nine areas of the patella. These lesions were analysed to determine the most common areas of degeneration in the femur and patella and to establish whether there was any pattern of degeneration between the patella and femoral lesions. The highest incidence of degeneration was found in the medial femoral condyle, central and central-medial patella, probably the areas of highest load in the knee. The areas of least degeneration were in the lateral femur and the superior patella, which are probably the lowest weight-bearing areas. Any pattern of patellar degeneration can occur with any pattern of femoral degeneration. Lateral and central-patellar facet degeneration are well-recognised clinical and radiological entities. In this series, medial patellar facet degeneration was commonly found. Medial patellar facet degeneration is less well recognised and in the literature is referred to only as secondary to lateral release. In this series, patients with lateral releases were excluded. The medial facet is especially loaded in the flexed knee. A fixed flexion contracture, as is common in medial compartment osteoarthritis, explains the high incidence of medial facet degeneration. Standard patellar skyline views show only the unloaded medial facet. Medial patellar facet degeneration is probably more common than is recognised and may be a cause of unexplained anterior knee pain, especially in the flexed knee

When navigating patellofemoral/unicompartmental knee surgery, the surgeon makes assumptions based upon algorithms developed for total knee arthroplasty. In this study we set out to show how variable the normal knee is. Minor anatomical variations in the shape of our knee may make a big difference in terms of orientation and joint wear patterns. Tibial patho-morphology has been described as a factor that predisposes to medial compartment osteoarthritis of the knee (anteromedial-OA), yet this is limited to 2D analysis. We aimed to describe the 3D morphology of both the tibial and femoral components of the medial compartment of the knee. We hypothesized that morphological differences do exist between normal knees and those predisposed to osteoarthritis. A total of 20 normal (group A) and 20 pre-OA knees (group B) were included. Group A consisted of contra lateral knees of young patients (< 55 years) awaiting hip surgery and group B of asymptomatic contra lateral knees of patients awaiting unicompartmental knee arthroplasty (UKA). Using 3D reconstructions from CT scans, we analyzed the tibiofemoral joint, which consists of the femoral condyles and the tibial plateau. The femur was aligned to the transcondylar and anatomical axes. The medial femoral extension facet (MFEF) was modeled as a segment of a sphere. The offsets between the MFEF centre and the medial femoral flexion facet centre were measured. The MFEF radius and the MFEF 2D arc angle in the sagittal plane were also measured. The tibias were aligned for flexion-extension and varus-valgus to a flat portion of the flexion facet (flexion facet plane), which lie’s roughly perpendicular to the tibial mechanical axis. To control for axial rotation, the anatomical tibial axis was used. A model of analysis was developed by rotating several increments towards and away from the midline to obtain several sagittal section images. For each sagittal section the medial tibial extension facet (MTEF) slope angle, its length, and the medial tibial submeniscal plane (MTSP) angle and length were analyzed. The relative length proportions of the MTEF, medial tibial flexion facet and MTSP were also measured. The MFEF was larger and more offset in pre-OA knees. Pre-OA knees also had a significantly larger MFEF arc angle than normals (p< 0.05). The MTEF appeared similar between normal and pre-OA knees. The submeniscal plane was highly variable between subjects but on average horizontally inclined (median 0o, range −15–14o) and formed a crescent shape anteriorly. There was no significant difference in tibial measured parameters between normal and pre-OA tibias (p> 0.05). The method showed good reproducibility using intraclass correlation coefficient (ICC value> 0.9) and Bland-Altman plot analysis. This study gives the CAOS surgeon some interesting insights into the anatomical variation of the normal knee. We have found evidence of a predisposing patho-morphology to medial-OA in the femoral condyle, but not the tibia. There is evidence of an enlarged flatter extension facet on the medial femoral condyle in the pre-OA knees, with no significant difference in the geometry of the medial tibial plateau, which is now reliably defined based upon a flexion plateau frame of reference

During knee arthroplasty operations, it appeared that different patterns of patellar degeneration occur. To confirm this, 123 patellae were evaluated in a prospective study. The patellae of patients who had undergone patellar surgery or osteotomy were excluded. The femur was divided into three condyles and nine areas, and the patella into three facets and nine areas. Areas of grade-III or more degeneration on the patella and femoral condyle were recorded. In 74 knees (60%), the patellar degeneration was less than grade III. In 49 (40 %), the patellar degeneration was grade III or more. In these 49 knees, there were 122 lesions in the nine areas of the femur and 77 lesions in the nine areas of the patella. These lesions were analysed to determine the most common areas of femoral and patellar degeneration. Further analysis was undertaken to determine whether there was any pattern of degeneration between the patellar and femoral lesions. The medial femoral condyle, central and central-medial patella had the highest incidence of degeneration. These probably represent areas of greatest load-bearing in the knee. The areas with least degeneration were in the lateral femur and the superior patella, probably the lowest load-bearing areas. It was noted that any pattern of patellar degeneration could occur with any pattern of femoral degeneration. Lateral and central patellar facet degeneration is a well-recognised clinical and radiological condition. Medial patellar facet degeneration was a common finding. The medial facet is especially loaded in the flexed knee. A fixed flexion contractor, common in medial compartment osteoarthritis, may partially explain the high incidence of medial facet degeneration in these patients. Medial patellar facet degeneration is not a well-recognised condition and in the literature is generally considered secondary to lateral release. In this series, patients with lateral releases were excluded. Standard patellar skyline views show only the unloaded medial facet. Medial patellar facet degeneration is probably more common than is clinically recognised, and may account for unexplained anterior knee pain, especially in the flexed knee. In this situation, pain will be aggravated by a lateral retinacular release

Summary Statement. Spinal flexibility in bending and axial torque has been shown to exhibit very modest changes with advancing disc degeneration. This study is the first to address the possible relationship in pure anterior shear and no clear relationship was observed. Introduction. Disc degeneration (DD) is a risk factor for low back pain. Stable or unstable spine segments may be treated with an isolated decompression or instrumented stabilization, respectively. The effect of DD on spinal flexibility has been addressed by several groups in bending but not in shear; a highly relevant load direction in the lumbar spine is anterior shear. The objective of our study was to determine the effect of DD on anterior translation and specimen stiffness under shear loading in an in vitro model of degenerative spondylolisthesis. Methods. Magnetic resonance images were obtained for human cadaveric lumbar FSUs (N=30). Disc degeneration was assessed with the Pfirrmann five-point grading scale. Three surgeons independently graded the discs and the grade common to at least two of the surgeons was assigned to that specimen. Each specimen was then tested in three sequential states: intact, facet destabilization, and disc destabilization, with the latter two states representing the clinical scenario of degenerative lumbar spondylolisthesis. The specimens were loaded with a constant 300 N axial compressive force, representing body weight, combined with a cyclic anterior shear force (5–250 N). Vertebral translation was tracked with an optoelectronic motion capture system. Kruskal-Wallis ANOVA and multiple comparison Dunn's tests were performed to determine the effect of DD on anterior translation and specimen stiffness. Results. There was only one specimen with disc grade V, and it was grouped with specimens with disc grade IV for the statistical analyses. DD had no effect on anterior translation or specimen stiffness for the intact and disc destabilization conditions. In the facet destabilization condition, specimens with disc grade II translated more than those with disc grades IV and V (p=0.03). Stiffness increased with DD in the facet destabilization condition (ANOVA p=0.04; Dunn's test was not significant). However, we re-analyzed the data with each surgeon's disc grades and found no significant differences in any of the specimen conditions for all three surgeons. Discussion. In the original data analysis, the translation results showed a trend to reduced anterior translation in shear with advancing degeneration only in the facet destabilization condition. These results suggest that shear stiffness of an intact specimen is not affected by overall degeneration, except in the case where the facets are not competent to resist load. In the subsequent data analyses, no significant effects were found. These findings indicate the sensitivity of the analyses to the assignment of disc grade. There are numerous disc grading scales reported in the literature and it is not clear which scale best defines disc degeneration. We are continuing to assess our methods to determine the most appropriate method of defining disc degeneration by disc grade

Introduction:. Varus alignment of the knee is common in patients undergoing unicondylar knee replacement. To measure the geometry and morphology of these knees is to know whether a single unicondylar knee implant design is suitable for all patients, i.e. for patients with varus deformity and those without. The aim of this study was to identify any significant differences between normal and varus knees that may influence unicondylar implant design for the latter group. Methodology:. 56 patients (31 varus, 25 normal) were evaluated through CT imaging. Images were segmented to create 3D models and aligned to a tri-spherical plane (centres of spheres fitted to the femoral head and the medial and lateral flexion facets). 30 key co-ordinates were recorded per specimen to define the important axes, angles and shapes (e.g. spheres to define flexion and extension facet surfaces) that describe the femoral condylar geometry using in-house software. The points were then projected in sagittal, coronal and transverse planes. Standardised distance and angular measurements were then carried out between the points and the differences between the morphology of normal and varus knee summarised. For the varus knee group, trends were investigated that could be related to the magnitude of varus deformity. Results:. Several significant differences between normal and varus knees were found, but most of these were small differences unlikely to be clinically significant or have an influence on implant design. However, two strong trends were observed. Firstly, the version of the femoral neck was significantly less for patients with varus knees (mean difference 9°; p < 0.05). The second trend was a significant difference in the sagittal morphology of the medial condyle. The kink angle, the angle formed by the intersection of the circles fitted to the flexion and extension facet surfaces, and their centres (Figure 1) was either absent or small in normal knees (mean 1°). An absent kink angle occurs when the circle defining the flexion facet surface lies within or makes a tangent to the circle defining the extension facet. However, for varus knees, the mean kink angle was 9°, with positive correlation with the angle of varus deformity (Figure 2). Discussion:. Varus knees have a significantly larger kink angle than normal knees, influencing the relative positions of the flexion and extension facet spheres that define the medial condylar geometry, contributing to the commonly observed ‘flattening’ of the medial condyle in the sagittal plane. Varus knees are also associated with significantly less anteversion of the femoral neck. It has been shown that reduced femoral neck anteversion causes increased loading of the medial condyle [1], and our results support this finding. The data generated in this study will feed further biomechanical testing to investigate the influence of kink angle and femoral neck version on the kinematics and load distribution in the varus knee

The most common injury in rugby resulting in spinal cord injury (SCI) is cervical facet dislocation. We report on the outcome of a series of 57 patients with acute SCI and facet dislocation sustained when playing rugby and treated by reduction between 1988 and 2000 in Conradie Hospital, Cape Town. A total of 32 patients were completely paralysed at the time of reduction. Of these 32, eight were reduced within four hours of injury and five of them made a full recovery. Of the remaining 24 who were reduced after four hours of injury, none made a full recovery and only one made a partial recovery that was useful. Our results suggest that low-velocity trauma causing SCI, such as might occur in a rugby accident, presents an opportunity for secondary prevention of permanent SCI. In these cases the permanent damage appears to result from secondary injury, rather than primary mechanical spinal cord damage. In common with other central nervous system injuries where ischaemia determines the outcome, the time from injury to reduction, and hence reperfusion, is probably important. . In order to prevent permanent neurological damage after rugby injuries, cervical facet dislocations should probably be reduced within four hours of injury

Abstract. Objectives. Catastrophic neck injuries in rugby tackling are rare (2 per 100,000 players per year) with 38% of these injuries occurring in the tackle. The aim of this study was to determine the primary mechanism of cervical spine injury during rugby tackling and to highlight the effect of tackling technique on intervertebral joint loads. Methods. In vivo and in vitro experimental data were integrated to generate realistic computer simulations representative of misdirected tackles. MRI images were used to inform the creation of a musculoskeletal model. In vivo kinematics and neck muscle excitations were collected during lab-based staged tackling of the player. Impact forces were collected in vitro using an instrumented anthropometric test device during experimental simulations of rugby collisions. Experimental kinematics and muscle excitations were prescribed to the model and impact forces applied to seven skull locations (three cranial and four lateral). To examine the effects of technique on intervertebral joint loads the model's neck angle was altered in steps of 5° about each rotational axis resulting in a total of 1,623 experimentally informed simulations of misdirected tackles. Results. Neck flexion angles and cranial impact locations had the largest effects on maximal compression, anterior shear and flexion moment loads. During posterior cranial impacts compression forces and flexion moments increased from 1500 to 3200 N and 30 to 60 Nm respectively between neck angles of 30° extension and 30° flexion. This was more evident at the C5-C6 and C6-C7 joints. Anterior shear loads remained stable throughout neck angle ranges however during anterior impacts they were directed posteriorly when the neck was flexed. Conclusions. The combination of estimated joint loads in the lower cervical spine support buckling as the primary injury mechanism of anterior bilateral facet dislocations observed in misdirected rugby tackles and highlights the importance of adopting a correct tackling technique. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Purpose: At present there is no reported, valid and reproducible model of degenerative spondylolisthesis for biomechanical testing of spinal implants. The purpose of this study was to create a single functional spinal unit (FSU) model that could demonstrate anterolisthesis consistent with low grade degenerative spondylolisthesis under physiologic shear loads. Method: Eight fresh-frozen human cadaveric, lumbar FSU’s were potted and secured in a custom jig for pure shear testing. The cranial segment was loaded from – 50N (posterior) to 250N (anterior) over three cycles for each of five test conditions with a 300N preload. Test conditions addressed known restraints to shear translation and were performed in the same order for all specimens, and included: intact, facet capsulectomy and bilateral two mm facet gap, bilateral four mm facet gap, nucleotomy, and annular release. Three-dimensional motion was recorded using an optoelectronic camera system. Results: Mean anterior translation at 250N for the five test conditions was 0.7 mm (95% confidence interval 0.4 to 0.9), 1.2 mm (0.9 to 1.6), 1.5 mm (1.1 to 2.0), 1.9 mm (1.4 to 2.4) and 3.1 mm (2.2 to 4.0). The mean maximum anterior translation was significantly different for each test condition with two exceptions. The four mm facet gap did not result in a significantly different maximum anterior translation compared to the two mm facet gap or the nucleotomy. There were no differences in off-axis motion (lateral or superior-inferior translation, flexion-extension, axial rotation, lateral bending) between the five test conditions. Conclusion: Anterior translation consistent with low grade degenerative spondylolisthesis was repeatedly demonstrated under physiologic shear loads using this model. All sequential destabilizations preserved anatomy critical for the application of pedicle screw constructs, interbody devices and interspinous spacers. As such, this model is appropriate for biomechanical testing of implants currently used in the treatment of low grade degenerative spondylolisthesis

Background: The Evans osteotomy has been proven to be very effective in treating flatfoot deformity in adults. However, it has not been shown whether the site of osteotomy influences the contact areas and peak pressures within the subtalar joint. It is hypothesized that the posterior facet of the calcaneus rotates posteriorly and laterally resulting in altered contact characteristics and peak pressures in the subtalar joint. Materiala and Methods: We used a finite-element model (FEA) of the hindfoot. Computed tomography slides of patients who suffered from adult flatfoot deformity were prepared by means of open-source software and converted into a three-dimensional model of the hindfoot. The FEA model allows the virtual performance of an osteoteomy and simulates force transmissions through the hindfoot and calculates joint contact characteristics and peak pressure alterations as well. Two different kind of osteotomies were tested:. an osteotomy 10mm proximal to the calcaneocuboid joint line and. an osteotomy performed adjacent to the posterior calcaneal facet. Results: There were small but significant differences found between osteotomies done either close to the calcaneocuboid joint or directly adjacent to the posterior facet. At both sites the posterior calcaneal facet rotated posteriorly and laterally. However we found a significant decreases in contact areas and raises in peak pressures within the subtalar joint in cases where the osteotomy was performed close to the posterior calcaneal facet. Summary: This study presents the effects of virtual Evans osteotomies on the subtalar joint and their dependence upon the site of the osteotomies

Purpose of the study: In accordance with the conclusions established at the SOFCOT symposium in 1988, we propose surgical treatment of displaced fractures of the calcaneus with screw fixation after reduction. We developed an original classification system of 3D computed tomography images which allows a precise description of the fractures and guides joint and calcaneal body reconstructions. The purpose of this work was to provide a precise analysis of operated fractures in order to identify prognostic factors and validate use of exclusive screw fixation for calcaneal fractures. Materials and methods: This series included 60 operated articular fractures of the calcaneus. The Uthéza classification was: 12 vertical, 7 horizontal with 1 fracture line, 3 horizontal with 2 fracture lines, 23 mixed with 1 fracture line and 15 mixed with 2 fracture lines. 3D computed tomography evidenced the fundamental fracture lines and their anterior extension. Fixation was achieved with one screw inserted in a transverse position under the posterior facet and one oblique screw from the greater tuberosity to the sustentaculum tali. The medial and lateral Böhler angles were measured on plain x-rays. The analysis included search for a double line on the posterior talocalcaneal facet, secondary body displacement, the position of the oblique screw and the degree of posttraumatic subtalar wear. The clinical criteria established in the 1988 SOFCOT guidelines were recorded. Analysis of variance, Pearson and Spearman coefficients, and RIDITS analysis (the most powerful method available for evidencing a relationship between two qualitative variables one of which is ordinal) were used to search for prognostic elements and correlations. Results: No severe complications were encountered with the wide lateral access. A negative medial Böhler angle was significantly correlated with an additionnal posterior facet line. A mean 80 p. 100 reduction in the lowering of the medial part of the posterior facet and an 87 p. 100 reduction in lateral pivoting were achieved irrespective of the type of fracture. Minimal secondary body displacements were significantly related to anchorage of the oblique screw outside the sustentaculum tali. Functional outcome was satisfactory (very good + good + average) in 75 p. 100 of the cases and physical outcome in 50 p. 100 (very good + good) irrespective of the type of fracture. Outcome was significantly correlated with reduction in the Böhler angle, double lines on the posterior facet, secondary displacement and osteoarthritis. Discussion: The 3D analysis of posterior facet fractures using our classification was useful in guiding reconstruction with correction of the medial lowering and the lateral pivoting. A negative medial Böhler angle was a factor of poor prognosis: more posterior facet lines, joint wear and deterioration of the functional and physical outcome. Good outcome required good reduction of the Böhler angle and good anchorage of the oblique screw in the sustentaculum tali. Good subtalar mobility was associated with pain relief. Uniform anatomic and pathologic classifications and precise analysis criteria are needed for pertinent comparison between series and proper definition for indications for first-line reconstruction-arthrodesis. Conclusion: Measurement of the medial Böhler angle improves the sensitivity of revision criteria for articular fractures of the calcaneus. Screw fixation has proven its reliability

Purpose And Background: In patients with chronic low back pain (LBP), selective injection procedures (provocative discography, medial branch, facet and sacroiliac joint blocks) have shown the pain source to be the intervertebral disc in 40%, the sacroiliac joint in 13–19% and the facet joints in 15–40%. No individual features in the history or examination are of consistent discriminatory value in diagnosis. This study aimed to assess whether patients with different pain sources could be differentiated using the Oswestry Disability Index (ODI) (a validated patient questionnaire scoring ten different aspects of pain and function in patients with LBP; higher scores correlating with greater disability). Methods And Results: ODI scores were recorded from 67 patients (46 female, age 17–82) whose source of LBP was subsequently confirmed by selective injection. The scores for each section of the ODI were compared between patients grouped according to pain origin; disc (n=11), sacroiliac (n=31) or facet (n=25). Patients with disc pain had significantly greater overall disability and scored higher for sitting, sleeping and social activity than those with facet or sacroiliac pain as judged by the 95% confidence limits of the median (p< 0.05). Patients with facet pain scored higher for walking and standing compared to those with sacroiliac pain. For disc pain scores were higher for sitting and standing than for walking, and for facet pain scores were higher for standing than for sitting or walking. Conclusion: Although the ODI is not a diagnostic tool, analysis of its components reveals characteristic pain and disability patterns in patients sub-grouped according to pain source

The purpose of our study is to assess the degenerative changes in the motion segments above a L5S1 spondylolytic spondylolisthesis, and to analyse the factors that contribute towards a retro-listhesis in the segment immediately above the slip. Prospective radiographic case series. 38 patients with a symptomatic L5S1 spondylolytic spondylolisthesis, with a mean age of 52.8 yrs (95% CI 47.2 – 58.4). 55.3% (n = 21) were females and 44.7% (n = 17) males. 58% (22) had grade 1 and 42% (16) grade 2 slips. Plain radiographs: Lumbar lordosis, slip angle, sacral slope, grade of the slip, and retro-listhesis at L45. MRI scans: facet angles at L34 and L45, facet degenerative score at L34 and L45 (cartilage and sclerosis), disc degenerative score at L45 and L5S1 (Pfirrmann). The Pfirmann disc score for L45 was 2.75 and L5S1 4.4 (p < 0.0001); the mean facet angle at L34 50.9° and L45 57.9° (p = 0.001) and the facet score at L34 was 8 and at L45 was 10.5 (p = 0.0001). 29% (11) demonstrated a retrolithesis at L45. Analysing the effect of these factors on the causation of retro-listhesis at L45 (table) the slip angle and L45 disc degenerative score were the only factors that predicted a retro-listhesis. There is a cascade of degenerative changes involving both the disc and the facet joints at the levels above a spondylolytic spondylolisthesis. The degenerative changes at the L45 disc and a higher slip angle predict a retro-listhesis at the level above the slip

Introduction:. The insertion footprint of the different muscles tendon fascicles of the Achilles Tendon on the calcanium tuberosity has not been described before. Method:. Twelve fresh frozen leg specimens were dissected to identify the different Achilles Tendon fascicles insertion footprint on the calcaneum in relation to their corresponding muscles. Further ten embalmed cadaveric leg specimens were examined to confirm an observation on the retrocalcaneal bursa. Results:. The superficial part of the AT insertion is made by tendon fascicles from the medial head of the gastrocnemius muscle which insert over the entire width of the inferior facet of the calcaneal tuberosity. In three specimens, this insertion had continuity with the plantar fascia in the form of periostium. The deep part of the TA insertion is made of fascicles from the soleus tendon which insert on the medial aspect of the middle facet of the calcaneal tuberosity while the lateral head of the gastrocnemius tendon fascicles insert on the lateral aspect of the middle facet of the calcaneal tuberosity. A bicameral retrocalcaneal bursa was present in 68% of examined legs. Conclusion:. This new observation and description of the Achilles insertion footprint and the retrocalcaneal bursa may allow a detailed understanding of the function of each muscular part of the gastrosoleous complex. This has potential significant clinical relevance in the treatment of Achilles pathologies around its insertion

The total disc replacement (TDR) devices are gaining popularity because of their capability of allowing joint motion at the index level. Studies have shown that motion preservation can reduce the likelihood of further degeneration at the adjacent level with better surgical outcome. Current lumbar TDR devices require an anterior approach for implantation. However, it is known that its clinical outcome may depend on implant insertion and placement during surgery. Only limited number of biomechanical studies regarding the effect of placement orientation on the clinical outcome is currently available. The purpose of this study was to investigate effects of various surgical placement of a lumbar TDR on the kinematics and load-sharing characteristics using finite element method (FEM). A previously-validated 3-D nonlinear FE model of the intact lumbar motion segment (L3-S1) based on computer tomography (CT) images of a cadaveric specimen (male, age 56, no pathologies) was used as the baseline FE model. Then, implantation of ProDisc-L (Spine Solutions, Inc., Synthes, Paoli, PA, USA) was simulated into the L4–L5 disc space through anterior approach with removal of the nucleus, anterior longitudinal ligament, and the anterior part of the annulus. The location of lumbar TDR was varied in the sagittal and the coronal planes. In the sagittal plane, the implants were placed anteriorly at 3-mm (S-3), 5-mm (S-5), and 7-mm (S-7) offset from the posterior margin of the endplate. In the coronal plane, the devices were shifted from the baseline position laterally to the right by 1-mm (C-1), 2-mm (C-2), and 3-mm (C-3) from the mid-sagittal line along the lower endplate. All of the models were subject to 150N compressive pre-load and flexion/extension moments of 10Nm at the superior endplate L4, while the inferior endplate of L5 was fully constrained. Changes in motion (ROM) and facet loads at the index and adjacent levels were assessed at different implant position. Results showed that deviation from the central placement (from S-3 to S-7 and from C-1 to C-3) decreases ROM while increasing facet load at the index level. The effect was more pronounced in the sagittal plane than in the coronal plane:10% decrease in ROM and 1% increase in facet load in the sagittal plane vs. no significant change in the coronal plane. As expected, changes were more evident during extension than in flexion. While the kinematics of the spine was restored to the pre-operative stage at the index level (L4-5), the ROM decreased at the adjacent level (L5-S1) in a compensating manner. The overloading of the facet seemed to indicate mal-alignment of the implant can further trigger facet degeneration, which may require unwanted revision or additional surgical treatment

The rotator cuff is sited on the anatomical neck of the humerus and is formed by the insertion of the supraspinatus (SP), infraspinatus (IS), teres minor (TM) and subscapularis. All play a vital role in the movement of the glenohumeral joint, and the anatomy is of critical importance in arthroscopic rotator cuff repair. We undertook an osteological and gross anatomical dissection study of the insertion mechanism of these tendons, in particular the SP . The SP inserts by a triple or quadruple mechanism. The ‘heel’ (medial) and capsule fuse, inserting into the anatomical neck proximal to the anterior facet of the greater humeral tubercle. The ‘foot arch’ inserts as a strong, flat, fibrous tendon into the facet. This area is cuboidal, rectangular, or ellipsoid, and measures 36 mm. 2. to 64 mm. 2. In about 5%, the insertion is fleshy (pitted), rendering it weaker than a tendinous attachment. The ‘toe’ lips over the edge of the facet laterally and fuses with the periosteum, fibres of the inter-transverse ligament and the IS. A proximal ‘hood’ of about 4 mm stretches down inferiorly and fuses with the periosteum of the humeral shaft. The subacromial or subdeltoid synovial bursa are sited laterally. The IS and TM insert into the middle and posterior facets (225 mm and 36 mm. 2. ) at respective angles of 80° and 115°. The inferior portion of the TM facet is not fused with the shoulder capsule. The subscapularis inserts broadly into the lesser tubercle, and the superior fibres fuse with the shoulder capsule and intertransverse ligament. The insertion of the subscapularis does not contribute directly to the formation of the ‘hood’, which belongs exclusively to the SP, IP and TM. This study confirms the complexity of the SP insertion and suggests that an unfavourable attachment or biomechanical anatomical malalignment may lead to eventual tendon/cuff degeneration

1. During a fifteen-year period a clinical, radiological and in some cases a surgical study has been made of 319 patients suffering from spondylolisthesis–that is, forward slipping of one lumbar vertebra on another or forward sagging of the whole lumbar spine in relation to the sacrum. 2. The five etiological factors are described, and the cases are assigned to five groups according to the factor responsible for the slip. In every case slipping is permitted by a lesion of the apparatus which normally resists the forward thrust of the lower lumbar spine–that is, the hook of the neural arch composed of the pedicle, the pars interarticularis and the inferior articular facet engaging caudally over the superior articular facet of the vertebra below. 3. In Group I (congenital spondylolisthesis–sixty-six cases) the lesion is a congenital defect of the facets. In Group II (spondylolytic spondylolisthesis–164 cases) the lesion occurs in the region of the pars interarticularis and is either an elongation of the bone or a break in continuity. There are reasons for thinking that the lesion is caused by stress over a long period rather than by acute injury or by a congenital anomaly of ossification. In Group IV (degenerative spondylolisthesis–eighty cases) the lesion of the facets is degenerative. There are no good grounds for thinking that an abnormality of the angle between the facets and the pedicles is the primary lesion behind the degenerative change. 4. Group III and V comprise few cases. In the former (traumatic spondylolisthesis–three cases) the lesion–a fracture of the neural arch–is caused by a single severe injury. In Group V (pathological spondylolisthesis–six cases) the slipping is caused by weakness of bone from various causes. 5. A full description is given of the etiological and biomechanical features of each group. A special investigation has been made into the etiological factors in degenerative spondylolisthesis. 6. The incidence of involvement of nerve tissues is highest in degenerative spondylolisthesis; the most severe degrees of slip are found in congenital spondylolisthesis

We have studied fracture-dislocation of the fifth lumbar vertebra in seven patients and reviewed 50 previously reported cases. Based on this information, we have classified the injury into five types: type 1, unilateral lumbosacral facet-dislocation with or without facet fracture; type 2, bilateral lumbosacral facet-dislocation with or without facet fracture; type 3, unilateral lumbosacral facet-dislocation and contralateral lumbosacral facet fracture; type 4, dislocation of the body of L5 with bilateral fracture of the pars interarticularis; and type 5, dislocation of the body of L5 with fracture of the body and/or pedicle, with or without injury of the lamina and/or facet. Conservative treatment of fracture-dislocation of L5 is generally not effective because the lesion is fundamentally unstable. Planning of the operation should be made on the basis of the various types of injury

Background: Calcaneonavicular coalitions (CNC) have been reported to be associated with anatomical aberrations of either the calcaneus and/or navicular bones. These morphological abnormalities may complicate accurate surgical resection. Three-dimensional analysis of spatial orientation and morphological characteristics may help in preoperative planning of resection. Materials and Methods: Sixteen feet diagnosed with CNC were evaluated by means of 3D CT modeling. Three angles were defined that were expressed in relation to one reproducible landmark (lateral border of the calcaneus): the dorsoplantar inclination, anteroposterior inclination and socket angle. The contact surface area was determined from the depth and width of the coalitions. Three-dimensional reconstructions of the calcanei evaluated the presence and morphology of the anterior calcaneal facet and of a navicular beak. The inter-observer correlations were assessed for the accuracy of the measurement methods. Sixteen normal feet were used as controls for comparison of the socket angle and anatomy of the anterior calcaneal facet and of the navicular beak. Results: The dorsoplantar inclination angle averaged 50° (±17), the anteroposterior inclination angle 64° (±15), and the pathologic socket angle 98° (±11). The average contact area was 156mm2. Ninety-four percent of all patients in the CNC group revealed a plantar navicular beak. In 50% of those patients the anterior calcaneal facet was replaced by the navicular portion and in 44% the facet was totally missing. In contrast, the socket angle in the control group averaged 77° (± 18), which was found to be statistically different than the CNC group (p=0.0004). Only 25% of the patients in the control group had a plantar navicular beak. Statistically significant inter-observer correlations were found for all measured angles. Conclusions: Computer aided CT analysis and reconstructions help to determine the spatial orientations of CNC and provide useful information in order to anticipate morphological abnormalities of the calcaneus and navicular

In six unloaded cadaver knees we used MRI to determine the shapes of the articular surfaces and their relative movements. These were confirmed by dissection. Medially, the femoral condyle in sagittal section is composed of the arcs of two circles and that of the tibia of two angled flats. The anterior facets articulate in extension. At about 20° the femur ‘rocks’ to articulate through the posterior facets. The medial femoral condyle does not move anteroposteriorly with flexion to 110°. Laterally, the femoral condyle is composed entirely, or almost entirely, of a single circular facet similar in radius and arc to the posterior medial facet. The tibia is roughly flat. The femur tends to roll backwards with flexion. The combination during flexion of no antero-posterior movement medially (i.e., sliding) and backward rolling (combined with sliding) laterally equates to internal rotation of the tibia around a medial axis with flexion. About 5° of this rotation may be obligatory from 0° to 10° flexion; thereafter little rotation occurs to at least 45°. Total rotation at 110° is about 20°, most if not all of which can be suppressed by applying external rotation to the tibia at 90°

Cadaver knee joints were mounted so that life-like forces of weight-bearing were simulated. The patello-femoral contact areas were defined under load throughout the range of movement by the dye method. During movement from extension to 90 degrees of flexion a band of contact sweeps across the patella from inferior to superior pole, but the odd facet makes no contact. At about 135 degrees of flexion separate medial and lateral contact areas form, the medial one limited to the odd facet. From extension to 90 degrees of flexion the patella holds the quadriceps tendon away from the femur, but in further degrees of flexion an extensive "tendo-femoral" contact area forms. Between 90 degrees and 135 degrees of flexion the patella rotates and the ridge between the medial and odd facets engages the femoral condyle. The odd facet is shown to be a habitual non-contact area and the ridge to be subject to high load, observations which correlate with cartilage lesions described in Part 2 of the paper