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