Adolescent idiopathic scoliosis (AIS) is a poorly understood progressive curvature of the spine. The 3-dimmensionnal spinal deformation brings abnormal biomechanical stresses on the load-bearing organs. We have recently reported for the first time the presence of facet joint cartilage degeneration comparable to age-related osteoarthritis in scoliotic adolescents. To better understand the degenerative mechanisms and explore new therapeutic possibilities, we focused on Toll-like receptors (TLRs) which are germline-encoded pattern recognition receptors that recognize pathogens and endogenous proteins such as fragmented extracellular matrix components (alarmins) present in intervertebral discs (IVD) and articular cartilage. Once activated, they regulate the production pro-inflammatory cytokines, proteases and neurotrophins which can lead to matrix catabolism, inflammation and potentially pain. These mechanisms have however not been studied in the context of AIS or facet joints. Facet joints of AIS patients undergoing corrective surgery and of cadaveric donors (non-scoliotic) were collected from consenting patients or organ donors with ethical approval. Cartilage biopsies and chondrocytes were isolated using 3mm biopsy punches and collagenase type 2 digestion respectively. qPCR was used to assess gene expression of the degenerative factors (MMP3, MMP13, IL-1ß, IL-6, IL-8) The biopsies were cut into two equal halves, one was treated for 4 days with a TLR2 agonist (Pam2CSK4, Invivogen) in serum-free chondrocyte media while the other one was cultured in media alone. MMP3, MMP13, IL-6 and IL-8 ELISAs and DMMB assays were performed on the biopsy cultured media. The ex vivo cartilage was then fixed, cryosectionned and also stained with SafraninO-Fast Green dyes. Baseline gene expression levels of TLR1,−2,−4,−6 were all upregulated in scoliotic chondodryctes compared to non-scoliotic. Pearson correlation analysis revealed that all TLR1,−2,−4,−6 gene expression correlated strongly and significantly with degenerative markers (MMP3, MMP13, IL-6, IL-8) in scoliotic chondrocytes but not in non-scoliotic. (Figure 1) When monolayer facet joint chondrocytes were activated with Pam2CSk4, there was a significant upregulation in previously described degenerative markers, TLR2 and NGF, a potent neurotrophin. These findings were strengthened by protein secretion analysis of select markers such as MMP-3, −13, IL-6 and IL-8 which were all upregulated after TLR2 activation. The scoliotic biopsies which were treated with Pam2CSK4 had a significant loss of proteoglycan content as shown by histology, was reflected in the proteoglycan content found in the media by DMMB. TLR gene expression levels were upregulated and correlated with proteases and pro-inflammatory cytokines in degenerating scoliotic cartilage, suggesting they promote cartilage degradation, especially considering the lack of correlations in non-scoliotic healthy cartilage. Furthermore, when TLRs are activated by Pam2CSK4 it triggers the release of the same proteases and pro-inflammatory cytokines in our ex vivo experiment. All this exacerbates the loss of proteoglycan in the cartilage ex vivo model after four days of insult with a TLR2 specific agonist. These results suggest that TLRs are an important pathway partaking in the cartilage degeneration of scoliotic facet joints and potentially all cartilage beyond our scope. Future studies aim at blocking TLRs to alleviate proteolysis and inflammation. For any figures or tables, please contact the authors directly

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

In a study on ten fresh human cadavers we examined the change in the height of the intervertebral disc space, the angle of lordosis and the geometry of the facet joints after insertion of intervertebral total disc replacements. SB III Charité prostheses were inserted at L3-4, L4-5, and L5-S1. The changes studied were measured using computer navigation sofware applied to CT scans before and after instrumentation. After disc replacement the mean lumbar disc height was doubled (p < 0.001). The mean angle of lordosis and the facet joint space increased by a statistically significant extent (p < 0.005 and p = 0.006, respectively). By contrast, the mean facet joint overlap was significantly reduced (p < 0.001). Our study indicates that the increase in the intervertebral disc height after disc replacement changes the geometry at the facet joints. This may have clinical relevance

Introduction Local steroid injection is commonly performed as a treatment for facet joint arthritis in the lumbosacral spine. The injection is performed under image guidance for which some surgeons utilise antero-posterior (A-P) imaging only while others prefer oblique imaging. The entry point and the direction of the needle entering into the facet joint are different in these techniques. Further the difficulties encountered in both the techniques are different. Purpose To find out the difference in the functional outcome in patients who received the facet joint steroid injection by A-P imaging and those who had the injection by oblique imaging. Material and Methods A prospective randomised controlled trial was performed by randomly allocating the 20 patients who was diagnosed to have facet joint arthritis clinically and by magnetic reasonance image scans, and who were then placed in the list for facet joint injections. Ten patients in Group I received the facet joint injections with A-P imaging while 10 patients in Group II received the facet joint injections with oblique imaging using image intensifier. All the patients received 40mg of methylprednisolone acetate with 1mL of 1% lignocaine and 1mL of 0.5% bupivacaine to each joint. The duration of the entire procedure was noted. Short Form-36 (SF-36) questionnaire was used before the procedure and at six weeks after the procedure to assess the functional outcome. Results All the patients were followed up for a period of six weeks. The mean age was 51.3 yrs in Group I and 48.3 yrs in Group II. The male to female ratio was 3:7 in Group I and 2:5 in Group II. One patient in Group I had the facet injections at only one level (L4/5 or L5/S1) while it was in two patients in Group II. Further one patient in Group I and one in Group two had unilateral facet joint injections at two levels. All the other patients had bilateral facet joint injections at two levels (L4/5 and L5/S1). One patient was excluded from the study as the A-P image obtained was very poor and that an oblique image had to be performed to visualise the facet joint because of obesity. The mean duration of the procedure was 18.33 min (10–25 min) in Group I and 22 min (10–35 min) in Group II (p=0.14, 95%CI −8.5 to +1.4). The patient function score improved from a mean of 20.0% to 32.5% after the injection in Group I, and from 30.0% to 41.0% in Group II. The pain score improved from a mean of 33.3% to 47.2% in Group I, and from 35.6% to 44.4% in Group II. The difference in physical function score (p=0.85, 95% C.I. −15.29 to +18.29), and pain score (p=0.71, 95% C.I. −24.21 to +34.22) between the two groups were not statistically significant. Conclusions There is no difference in the functional outcome of patients treated by facet joint injections using A-P or oblique imaging. However, with experience we found that it may be difficult to visualise the facet joint clearly by A-P imaging alone in obese individuals

Introduction: Pathological changes in the elderly spine include intervertebral disc degeneration, apophyseal joint arthritis and osteoporotic fracture of the vertebral body. Such changes are likely to be inter-related through alterations in the sharing of load between the apophyseal joints and the intervertebral disc unit. We describe an accurate, non-destructive method for calculating the load sharing based on measurements of the distribution of stress within the intervertebral disc. Materials and Methods: Twenty three motion segments, consisting of two vertebrae and the intervening disc and ligaments, were dissected from 17 human lumbar spines. A preliminary “creep” test was used to reduce disc height and water content by an amount equivalent to the diurnal variation seen in vivo. Then, a constant load was applied to each motion segment, using a computer-controlled hydraulic materials testing machine, for a period of 20s while a pressure-transducer, sensitive to spatial variations in compressive stress, was pulled through the disc along its mid-sagittal diameter. Profiles of vertically-acting compressive stress were obtained in each disc positioned in 2° of extension (appropriate for an erect standing posture). The total compressive force acting on the intervertebral disc was calculated by modelling the disc using approximately 20 elliptical rings of known cross-sectional area. The force acting on each ring was given by the product of area and the average compressive stress acting on it, which was obtained from the appropriate region of the stress profile. The total force acting through the disc was obtained by summing up the force contribution from each ring. The force acting on the apophyseal joints was calculated from the difference between applied (known) load and the calculated load acting on the disc. A correction factor was obtained separately for each disc to account for deviations in the cross-section from the elliptical, and variations in the sensitivity of the transducer in disc tissues of different ages. The correction factor was obtained by comparing the applied force with the force calculated from a stress profile measured before creep loading while the disc was in a neutral position, when the load passing through the apophyseal joints is negligible. Results: The proportion of load passing through the apophyseal joints increased significantly with age (r. 2. =0.48, p< 0.01), from 7% at age 27 yrs to 42% at 82yrs. Similarly, the proportion of load passing through the apophyseal joints increased with degree of disc degeneration (r. 2. =0.5, p< 0.05 Pearson, Chi-square) from 8% in “grade 1” discs to 40% in “grade 4” discs. Discussion: The compressive load passing through the apophyseal joints is higher than that predicted by previous, inaccurate, methods, or by experiments which failed to reduce the height and water content of the intervertebral disc. Increased load-bearing may be a contributing factor in apophyseal joint degeneration. Also, in lordotic postures, “stress shielding” by the apophyseal joints could contribute to bone loss in the vertebral body, leaving it vulnerable to osteoporotic fracture when the spine is loaded in flexion

Introduction Local steroid injection is commonly performed as a treatment for facet joint arthritis in the lumbosacral spine. The injection is performed under image guidance for which some surgeons utilise antero-posterior (A-P) imaging only while others prefer oblique imaging. Purpose The aim of this study is to find out the difference in the functional outcome in patients who received the facet joint steroid injection by A-P imaging and those who had the injection by oblique imaging. Material and Methods A prospective randomised controlled trial was performed by randomly allocating the 20 patients who were diagnosed to have facet joint arthritis clinically and by magnetic reasonance image scans, and who were then placed in the list for facet joint injections. Ten patients in Group I received the facet joint injections with A-P imaging while 10 patients in Group II received the facet joint injections with oblique imaging using image intensifier. All the patients received 40mg of methylprednisolone acetate with 1mL of 1% lignocaine and 1mL of 0.5% bupivacaine to each joint. The duration of the entire procedure was noted. Short Form-36 (SF-36) questionnaire was used before the procedure and at six weeks after the procedure to assess the functional outcome. Results All the patients were followed up for a period of six weeks. The mean age was 51.3 yrs in Group I and 48.3 yrs in Group II. The male to female ratio was 3:7 in Group I and 2:5 in Group II. One patient in Group I had the facet injections at only one level while it was in two patients in Group II (L4/5 or L5/S1). Further one patient in Group I and one in Group two had unilateral facet joint injections at two levels. All the other patients had bilateral facet joint injections at two levels (L4/5 and L5/S1). One patient was excluded from the study as the A-P image obtained was very poor and that an oblique image had to be performed to visualise the facet joint because of obesity. The mean duration of the procedure was 18.33 min (10–25 min) in Group I and 22 min (10–35 min) in Group II (p=0.14, 95%CI −8.5 to +1.4). The patient function score improved from a mean of 20.0% to 32.5% after the injection in Group I, and from 30.0% to 41.0% in Group II. The pain score improved from a mean of 33.3% to 47.2% in Group I, and from 35.6% to 44.4% in Group II. The difference in physical function score (p=0.85, 95% C.I. −15.29 to +18.29), and pain score(p=0.71, 95% C.I. −24.21 to +34.22) between the two groups were not statistically significant. Conclusions There is no difference in the functional outcome of patients treated by facet joint injections using A-P or oblique imaging. There is no significant difference in the duration of the procedure as well between the two techniques. However, with experience we found that it may be difficult to visualise the facet joint clearly by A-P imaging alone in obese individuals

Backpain is a common cause of patient referral to pain clinics. Around 120 000 patients with back pain are seen in UK Pain Clinics every year. Facet joint injections are a commonly used treatment modality. However there is considerable controversy regarding their efficacy. Most of the evidence supporting the use of injections is anecdotal, rather than being based on randomised studies. We carried out a prospective study to assess the efficacy of facet joint injections in relieving chronic low back pain. Our study group comprised 41 patients (57% females, 43% males). Patients completed the Oswestry Disability Index (ODI) and marked their pain levels on a Visual Analogue Scale (1 to 10). We found that though the pain score improved from 6.9 to 4.3, there was only a marginal improvement in the ODI from 52.5 to 50.8. Overall 85 % of patients experienced some improvement, while 15% felt their symptoms had worsened after the injections. One of the most significant findings of this study was the fact that the improvement in most patients lasted only for an average of three weeks. This is significantly less than most previous studies indicate. Interestingly, inspite of this limited improvement, almost all patients expressed the desire to be placed back on the list for repeat injections. Our study demonstrated a beneficial short term effect of facet joint injections. In our opinion, they are a reasonable adjunct to non operative treatment of chronic backpain

A group of 109 patients with unilateral low back pain for over three months were randomised to receive one of three types of injection treatment: cortisone and local anaesthetic injected into two facet joints (28), the same mixture around two facet joints (39), or physiological saline into two facet joints (42). The effect of the treatment was evaluated in relation to work attendance, pain, disability and movements of the lumbar spine. Patients were examined one hour and two and six weeks after treatment and also completed a questionnaire after three months. A significant improvement was observed in work attendance, pain and disability scores, but this was independent of the treatment given and movements of the lumbar spine were not improved. Of the 70 patients with initial pain relief after injection, 36% reported persisting benefit at the three month follow-up, independent of the mode of treatment given. We conclude that facet joint injection is a non-specific method of treatment and the good results depend on a tendency to spontaneous regression and to the psychosocial aspects of back pain

Aims: Comparison of the effectiveness of the injection of hyaluronic acid (Ostenil¨) and cortisone (Volon¨) into the facet joints in the treatment of facet joint syndrome. Methods: 60 patients suffering from low back pain due to degenerative arthritis of the facet joints were included in this randomized, controlled, double-blinded, clinical trial. 30 patients received intra-articular injections of hyaluronic acid (Ostenil¨) and 30 patients received intra-articular injections of 10mg triamcinolon-hexacetonid (Volon 10¨). The facet joints of the spinal segments L3/L4, L4/L5, and L5/S1 were injected bilaterally with computed tomography guidance in intervals of one week each. Clinical evaluation was carried out one week prior þrst injection, at the day of þrst injection, after one, two, and three weeks, and after three and six months. Clinical assessment was carried out using the visual analog scale for pain, the Roland Morris Questionnaire, and the Oswestry Disability Questionnaire. Quality of life was assessed using the SF-36 health questionnaire. Radiological assessment was done according to Kellgren. Results: Pain reduction was achieved faster in the Volon 10¨group. After three months the Ostenil¨group reached better pain reduction and this effect lasted for a longer period. The Roland Morris score, the Oswestry Disability Questionaire, as well as the Low Back Pain Outcome Score showed signiþcantly better results in the Ostenil¨group after 3 and 6 months follow-up. Conclusion: Even though no signiþcant difference was found in the short-term follow-up, the results in the Ostenil¨group were comparable to the Volon 10¨group, and were signiþcantly better in the long-term follow up. Thus the intra-articular injection of hyal-uronic acid (Ostenil¨) is an effective alternative in the treatment of low back pain caused by facet joint syndrome, avoiding the known side effects of cortisone

Cadaveric lumbar spine specimens of "motion segments", each including two vertebrae and the linking disc and facet joints, were compressed. The pressure across the facet joints was measured using interposed pressure-recording paper. This was repeated for 12 pairs of facet joints at four angles of posture and with three different disc heights. The results were that pressure between the facets increased significantly with narrowing of the disc space and with increasing angles of extension. Extra-articular impingement was found to be caused, or worsened, by disc space narrowing. Increased pressure or impingement may be a source of pain in patients with reduced disc spaces

Purpose and Background. This pilot study aimed to determine the accuracy of lumbar spine combined movement (CM) testing for diagnosing facet joint mediated pain, by comparing CM to medial branch blocks (MBB) - the gold standard in the diagnosis of facet joint pain. A regular compression pattern of CM combines active extension and lateral flexion, which is believed to compress the facet joints greater than physiological uni-planar movements. Method and Results. 96 patients attending a pain clinic day case unit for diagnostic MBB were recruited. Patients' pain responses to CMs were measured prior to and thirty minutes following MBB. The effect of weight bearing and recumbence, RMDQ, EQ-5D and MYMOP were also measured. The regular compression CM test had 80% sensitivity (95%CI: 71% to 89%) and 50% specificity (95%CI: 28% to 71%). The regular compression CM group had the largest pre-post VAS difference (median 4 points). The patients whose pain was not relieved in recumbence (n=15) showed a significant VAS difference of 6 points p=0.001). There was a significant positive correlation between the pre and post pain scores, p<0.001. There was no association between MBB response and RMDQ, EQ-5D, MYMOP scores, duration of symptoms or standing as a provoking activity. Conclusion. Regular compression CM testing can be used as a diagnostic tool to identify patients with facet joint mediated pain, particularly when associated with high pain scores. Low back pain (LBP) provoked by standing and relieved with recumbence are common features in the LBP population but are not indicators of facet joint pathology, contrary to many clinicians' beliefs

Background Context. SPECT-CT is a hybrid imaging modality, which has become very well established in the diagnosis of inflammatory, vascular and malignant processes affecting the spine. However, little evidence exists on its application with degenerative pathologies. Purpose & Study Design. Systematic review on the use of SPECT-CT in the diagnosis of degenerative facet joint arthropathy. Patient Sample. 824 patients across 10 studies conducted over the last 6 years (2012 – 2018), with a mean age of 51.8 years old. All studies excluded patients with malignancy, infection or inflammatory aetiologies or those related to acute trauma. Only degenerative pathologies of the lumbar spine in an adult population were included. Methods. A systematic review of the literature available on the topic was conducted using the PubMed, Cochrane, Medline and Embase online databases of journal articles. Results. Five studies focused on SPECT-CT alone / versus CT. Two focused on SPECT-CT vs MRI, and three focussed on SPECT-CT guided facet joint injections. Of these 10 studies, seven concluded with results supporting SPECT CT's use, two reported discordance between SPECT-CT findings with those diagnosed from clinical examination / MRI scans, and one study's conclusions were equivocal. Conclusion. SPECT-CT shows promise as an imaging adjunct in assisting with the diagnosis and subsequent treatment of degenerative facet joint arthropathies. In patients whose MRI scans reveal multiple potential pain generators, SPECT-CT could help differentiate between clinically significant sources of pain and may even serve a purpose in guiding facet joint injections in patients with inconclusive MRI / CT scans. No conflicts of interest. No funding obtained

Lumbar facet joint pain cannot be reliably diagnosed clinically, the International Spinal Injection Society recommends two diagnostic local anaesthetic blocks before radiofrequency (RF) denervation [. 1. ]. Scoring systems may improve diagnostic accuracy. The two most popular scores disagree on the interpretation of pain induced by extension/rotation:. ‘Cochin Criteria’ [. 2. ]: pain on extension/rotation _ not facet joint problem. Helbig & Lee [. 3. ]: pain on extension/rotation _ facet joint problem. Methods: Retrospective study of all patients who had RF denervations of the lumbar facet joints in 2004. Patients were selected clinically and did not undergo diagnostic blocks. Cochin criteria, Helbig & Lee scores, work status, and outcome were taken from the case notes. Likelihood ratios were calculated for the scores, their individual components, and work status. Results: 145 patients underwent RF facet joint denervation, for 127 all data was available. In 68 patients the procedure was successful (53.5%). Conclusion: Neither the Cochin Criteria nor the Helbig & Lee score can predict the response to radiofrequency denervation of the lumbar facet joints. Pain on extension/rotation weakly indicates a poor response to facet joint denervation. X-rays do not help with the diagnosis. Social factors may be more important than clinical signs

Aims: To assess the effectiveness of intra-articular facet joint injections in controlling disability in patients with low back pain. Methods: 100 consecutive patients admitted in our day case unit for facet joint injections were included in the study. Fluoroscopically controlled intra-articular facet joint block with injection of a local anaesthetic and corticosteroid suspension was performed after clinical and radiological assessment. Disability due to back pain was assessed by determining a revised Oswestry Low Back Pain Disability Index (Oswestry Score). The patients completed a questionnaire immediately prior to treatment, two weeks following injection and three months following injection. Results: Facet joint injections were performed for intervertebral disc prolapse (66%), spondylolysthesis (13%), spinal stenosis (10%), spondylosis (7%), and sacro-iliac joint pain (4%). The mean Oswestry Score prior to injection was 40.6% (95% conþdence interval 4.4), at two weeks following injection was 26.6% (95% conþdence interval 4.9) and at three months following injection was 21.5% (95% conþdence interval 4.8). 78% of the patients found the facet joint injections useful at 2 weeks following treatment and this þgure was maintained (79%) at 3 months after injection. No complications were reported following treatment. Conclusions: We have found intra-articular facet joint block for the treatment of low back pain a valid therapeutic option, acceptable by the patients and with negligible risks

Introduction. Total disc replacement (TDR) provides an alternative to fusion that is designed to preserve motion at the treated level and restore disc height. The effects of TDR on spine biomechanics at the treated and adjacent levels are not fully understood. Thus, the present study investigated facet changes in contact pressure, peak contact pressure, force, peak force, and contact area at the facet joints after TDR. Methods. Seven fresh-frozen human cadaveric lumbar spines were potted at T12 and L5 and installed in a 6-DOF displacement-controlled testing system. Displacements of 15° flexion/extension, 10° right/left bending, and 10° right/left axial rotation were applied. Contact pressure, peak contact pressure, force, peak force and contact area for each facet joint were recorded at L2-L3 and L3-L4 before and after TDR at L3-L4 (ProDisc-L, Synthes Spine). The data were analysed with ANOVAs/t-tests. Results. Axial rotation had the most impact on contact pressure, peak contact pressure, force, peak force, and contact area in intact spines. During lateral bending and axial rotation, TDR resulted in a significant increase in facet forces at the level of treatment and a decrease in contact pressure, peak contact pressure, and peak force at the level superior to the TDR. With flexion/extension, there was a decrease in peak contact pressure and peak contact force at the superior level. Conclusion. Our study demonstrates that rotation is the most demanding motion for the spine. We also found an increase in facet forces at the treated level after TDR. To our knowledge, we are the first to show a decrease in several biomechanical parameters after TDR at the adjacent superior level in a cadaveric model. In general, our findings suggest there is an increase in loading of the facet joints at the level of disc implantation and an overall unloading effect at the level above

The reproduction of symptoms on arthrography of the lumbar facet joint has been accepted as a screening procedure before localised spinal fusion. We studied the histology of 127 facet joints removed at operation from 84 patients, who had previously had facet arthrography. The specificity of the arthrographic results for degenerative joint disease was 75% but their sensitivity was only 59%. This gave a positive predictive value of 85%, but a negative predictive value of only 43%. We conclude that the production of symptoms during facet arthrography is of little value as a screening procedure

Giant-cell tumour of the synovium is known to affect the fingers or toes of adults. It has seldom been described in the spine and rarely in the thoracic vertebrae or in a child. The lesions of giant-cell tumour of the synovium have a classical radiological appearance, but require a high index of suspicion for correct recognition. Unlike giant-cell tumour of the synovium at other well-known sites, spinal lesions lack the characteristic papillary architecture, thereby raising other diagnostic possibilities. We describe a giant-cell tumour of the synovium of the left facet joint of a thoracic vertebra in a nine-year-old girl. The tumour was treated successfully by surgical excision

Therapeutic injection of facet joints is now widely practised, but British experience has been infrequently reported. We studied the results of injecting facet joints with a corticosteroid preparation in 50 patients suffering from the "facet syndrome". Our series included a number of extra-articular injections and these "failed injections" provide a useful control group. Results indicate that only intra-articular injections are effective; certainty of joint penetration can be ensured only by the routine use of joint arthrography

Background Context: One of the main postulated basic principles of total disc replacement (TDR) is the preservation of flexion/extension ability. In neutral position the ideal disc prosthesis should not stay in maximal possible extension which would imply an impingement of the prosthesis. An impingement would cause shear strains on the prosthesis endplates which probably accelerate loosening. Moreover an additional extension ability from the neutral position would indicate no impingement in the facet joints in neutral position and a physiological movement capability. Purpose: The purpose of study was to evaluate a possible impingement of the prosthesis or facet joints after TDR in neutral position. Study design: Prospective evaluation of radiological outcome measures after total disc replacement. Patient sample: The patients (19 female, 10 male) ranged from 29 to 56 years of age (mean: 42.46.5 years). The mean follow up interval averaged 13.2 months (range: 6 – 35 months). The diagnosis of degenerative disc disease was confirmed by MRI (black disc) and discography (positive „Memory pain“). Pain relief after facet joint infiltration was an exlucsion criteria. All patients had a single-level disc replacement (Prodisc II, Spine Solutions) with the same angulation (6). Outcome measures: Evaluation of a possible impingement of the prosthesis and impingement of facet joints in neutral position. Methods: A computer based analysis of pre- and postoperative lateral X-rays in neutral position and dynamic x-rays. The angulation of prosthesis in neutral position and the extension ability in dynamic x-rays were measured. Results: 15 patients showed no extension ability on dynamic x-rays and 10 of these 15 patients had an impingement with maximum extension of the prosthesis on x-rays in neutral position. In the remaining 14 patients the extension ability averaged pre-/postoperatively 2.3/1.3 (p=0.115). In 4 of the 14 patients the pros-thesis showed an impingement in maximum extension and in 10 patients the prosthesis was not in maximum possible extension. Conclusion: Due to the constrained design of the Pro-Disc an impingement is possible and was recognized in nearly 30% of the cases. The imbalance of flexion vs extension bending moments with increase in extension bending moments due to resection of the anterior longitudinal ligament and anterior anulus seems to be a possible explanation. It still remains unclear if an impingement will result in facet joint protection or will trigger a loosening of the implant. A prosthesis design which preserves the anterior longitudinal ligament would be probably a possible solution

Aims. The aim of this study was to compare the effect of a percutaneous radiofrequency heat lesion at the medial branch of the primary dorsal ramus with a sham procedure, for the treatment of lumbar facet joint pain. Patients and Methods. A randomised sham-controlled double blind multicentre trial was carried out at the multidisciplinary pain centres of two hospitals. A total of 60 patients aged > 18 years with a history and physical examination suggestive of facet joint pain and a decrease of ≥ 2 on a numerical rating scale (NRS 0 to 10) after a diagnostic facet joint test block were included. In the treatment group, a percutaneous radiofrequency heat lesion (80. o. C during 60 seconds per level) was applied to the medial branch of the primary dorsal ramus. In the sham group, the same procedure was undertaken without for the radiofrequency lesion. Both groups also received a graded activity physiotherapy programme. The primary outcome measure was decrease in pain. A secondary outcome measure was the Global Perceived Effect scale (GPE). Results. There was a statistically significant effect on the level of pain in the factor Period (T0-T1). However, there was no statistically significant difference with the passage of time between the groups (Group × Period) or in the factor Group. In the crossover group, 11 of 19 patients had a decrease in NRS of ≥ 2 at one month crossover (p = 0.65). There was no statistically significant difference in satisfaction with the passage of time between the groups (Group × Period). The independent factors Group and Period also showed no statistically significant difference. There was no statistically significant Group × Period effect for recovery, neither an effect of Group or of Period. Conclusion. The null hypothesis of no difference in the decrease in pain and in GPE between the treatment and sham groups cannot be rejected. Post hoc analysis revealed that the age of the patients and the severity of the initial pain significantly predicted a positive outcome. Cite this article: Bone Joint J 2016;98-B:1526–33