We report our early experience with the use of a new prosthesis, the Modular Hemipelvic Prosthesis II, for reconstruction of the hemipelvis after resection of a primary malignant peri-acetabular tumour involving the sacroiliac joint. . We retrospectively reviewed the outcome of 17 patients who had undergone resection of a pelvic tumour and reconstruction with this prosthesis between July 2002 and July 2010. One patient had a type I+II+III+IV resection (ilium + peri-acetabulum + pubis/ischium + sacrum) and 16 had a type I+II+IV resection (ilium + acetabulum + sacrum). The outcome was assessed at a mean follow-up of 33 months (15 to 59). One patient was alive with disease, 11 were alive without disease and five had died of disease. The overall five-year survival rate was 62.4%. Six patients had a local recurrence. The mean Musculoskeletal Tumour Society score was 58% (33 to 77). Deep infection occurred in two patients, problems with wound healing in five and dislocation in one. For patients with a primary malignant peri-acetabular sarcoma involving the sacroiliac joint, we believe that this new prosthesis is a viable option for reconstruction of the bony defect left following resection of the tumour. It results in a satisfactory functional outcome with an acceptable rate of complications. . Cite this article: Bone Joint J 2014;96-B:399–405

Sacroiliac joint (SIJ) fusion is a controversial yet last resort operative technique to address SIJ pain. The current study aims to determine the patient outcomes of SIJ fusions, in a single surgeon series utilising an anterior approach with 2 DC plates across the joint and iliac crest autograft. Retrospective case series involving 11 patients who had 13 SIJ fusions performed over an 8 year period (2002–2010). Patients were identified by electronic key word search from databases at Middlemore hospital and the private sector. Dictated clinic letters and operation notes were reviewed to obtain demographic data and outcomes data including complications. Postoperative radiology reports were reviewed to document radiographic fusion status. Telephone interviews were conducted to measure clinical outcome scores via the Majeed Pelvic Score and the 12-item Short-Form Health Survey (SF-12). 10 out of 11 patients (entailing 12 SIJ fusions) responded and participated in the study, equating to over 90% follow up. 2 cases were managed at Middlemore Hospital, with the remainder in the private sector. All cases but one had a ‘post-traumatic arthritis’ etiology. Diagnosis was made by CT guided local/steroid injection into the joint in conjunction with CT/bone scan/MRI imaging. The Majeed score improved markedly for 9 of 12 SIJ fusions (75%). 10 of 12 patients stated they would have the procedure again. 7 of 12 fusions (58%) had postoperative complications including blood loss, haematoma, nerve injury (including one case of permanent foot drop), non-union, infection of the joint/metal ware, hernia and urinary retention. 5 of 12 fusions (42%) experienced altered sensation over the lateral femoral cutaneous nerve distribution. All except one patient eventually had x-rays or CT scans postoperatively that reported radiographic fusion of the joint. In appropriately selected patients with SI joint arthrosis, 3/4 patients reported significant improvement in function and pain level after SIJ fusion. Chronic pain (from other sources) and major complications were a feature amongst those failing to benefit. Lateral femoral cutaneous nerve palsy has high incidence with the current operative technique

Crescent fracture dislocations are a well-recognised subset of pelvic ring injuries which result from a lateral compression force. They are characterised by disruption of the sacroiliac joint and extend proximally as a fracture of the posterior iliac wing. We describe a classification with three distinct types. Type I is characterised by a large crescent fragment and the dislocation comprises no more than one-third of the sacroiliac joint, which is typically inferior. Type II fractures are associated with an intermediate-size crescent fragment and the dislocation comprises between one- and two-thirds of the joint. Type III fractures are associated with a small crescent fragment where the dislocation comprises most, but not all of the joint. The principal goals of surgical intervention are the accurate and stable reduction of the sacroiliac joint. This classification proves useful in the selection of both the surgical approach and the reduction technique. A total of 16 patients were managed according to this classification and achieved good functional results approximately two years from the time of the index injury. Confounding factors compromise the summary short-form-36 and musculoskeletal functional assessment instrument scores, which is a well-recognised phenomenon when reporting the outcome of high-energy trauma

Purpose of the study: Primary bone tumors of the sacroiliac joint are difficult to diagnose. We present the procedure used to resect these tumors and reconstruct the pelvic ring, and the carcinological and functional outcome. Materials and Methods: This was a retrospective analysis of a consecutive series of patients treated for a tumor of the iliac bone or of the sacrum which involved the sacroiliac joint. Tumor grading was based on the Enneking classification and the functional outcome on the MSTS score. Results: From 1986 to 2003, 24 patients were treated for a a tumor involving the sacroiliac joint. Six with invasion of the sacral body. The histology was osteosarcoma (n=8), chondrosarcoma (n=8), malignant hystiocytofibroma (n=3), Ewing’s sarcoma (n=2), schwannoma (n=1), leiomysarcoma (n=1) and haemangiopericytoma (n=1). Seventeen patients were given neoadjuvant chemotherapy. A wide crest approach was used to access both aspects of the pelvic ring. Neurological sacrifice was required in six patients. Operative time was 5.27 hours on average. Reconstruction was achieved with an autograft and instrumentation. The resection was wide in 11 cases, marginal in 12, and contaminated in one. The mean follow-up was 4.77 years. Ten patients died from their disease. Survival was correlated with the quality of the resection and with the initial tumor stage. Hemisacrectomy did not affect survival. Bone healing was achieved in 13 patient, ten who survived. The mean MSTS score was 48% at last follow-up in 14 survivors. For the nine patients who did not require neurological sacrifice, the mean score was 58%. For the five other patients, the mean score was 38% This score was 65% in patients with bone healing and 8% in those with nonunion. Discussion: The survival of patients with a tumor of the sacroiliac joint is basically related to the histological diagnosis and the quality of the resection. If the disease can be controlled, the method of the reconstruction proposed here enables bone healing with a satisfactory functional result when neurological sacrifice can be avoided

Generally, the sacroiliac joint is not considered accessible for arthroscopy under physiological conditions. The non-injured joint is not large enough for introduction of even the smallest arthroscope into the joint space. After traumatic injury however, or in the event of an inflammatory condition or tumour formation, it is theoretically possible to position an endoscope in the joint space. Study of the anatomy of the sacroiliac joint and knowledge of the anatomic relations, particularly the vascular and nervous relations, is a prerequisite for arthroscopic exploration of the sacroiliac joint space. The posterior approach must account for the bone configuration of the iliac wing and the orientation of the sacroiliac joint line. A cadaver study confirmed the feasibility of endoscopic exploration of the sacroiliac joint via a posterior percutaneous access. Based on this anatomic experience, we positioned an arthroscope in an injured sacroiliac joint and report the different phases. A technique for obtaining a biopsy of the anterior aspect under endoscopic control has already been described, but to our knowledge, there is no arthroscopic description of the sacroiliac joint via a posterior access. Indications for arthroscopy of the sacroiliac joint remain very limited. This technique can be used to remove osteocartilaginous fragments or foreign bodies incarcerated in the joint and to obtain biopsy material, drain collections and, in the near future, should allow avivement of the cartilage surfaces with the objective of a percutaneous arthrodesis

Introduction Sacroiliac joint pain is resistant to diagnosis by clinical methods. CT guided diagnostic blocks are the gold standard in diagnosing SI joint pathology (Maigne J.Y. et al, Spine 1996). The current blocks have various pit falls. We have devised a new functional diagnostic block which is a modification of the currently available blocks for diagnosing sacroiliac joint pain. Methods The patient suspected of having sacroiliac joint pain undergoes a CT-guided sacroiliac joint catheterisation. The patient is subsequently admitted to the hospital for two full days. On admission patient is charted for an injection of either a local anaesthetic or normal saline (placebo) through the catheter into the joint 2–3mls every 3–4 hourly. Only one drug is administered on any given day. On day one, the nurse in charge of the patient by the flip of a coin will decide to give one of the drugs for the day, the patient or the treating doctor not aware of the drug injected. The first injection starts at 0600hrs and the last injection at 2200 hrs. The injection details and pain score are documented on a standardised form. The patient is then taken through a range of physical activity which usually provokes the sacroiliac joint pain. The next day, the patient receives the alternate drug and undergoes the same protocol. On the third morning the patient is discharged with an appropriate follow-up. The injection given, average pain score and the level of comfort with physical activity are summarised into a form. Discussion Our modified block has the following advantages, it is a double blinded assessment, the effect of a placebo can be tested, and it is also a functional assessment which is recorded over two days and not just a one-off response. The conclusion of the block is determined by the patient’s response and not examiner depended

Introduction. Percutaneous radiofrequency lesioning of the lateral branches of the sacroiliac joint has become a recognised method of treating chronic pain arising from this joint. Due to the large and varied innervation from the S1-3 lateral branches success has been achieved with large lesions that has a high chance of covering these nerves. Such lesions require specialised and expensive equipment and the NIMBUS needle is a large 17G electrode with expandable tines at the tip. It is compatible with all standard radiofrequency probes and it produces a large lesion at the tip. It has been in use in the USA in over 100 cases and we describe its use in the UK. Methods. Patients were identified as having sacroiliac joint pain by clinical assessment and positive pain response to local anaesthetic sacroiliac joint lateral branch blocks. Under fluoroscopic control, the needle is inserted at the lateral edge of the sacral S1-3 posterior foramen. Three lesions at the lateral edge of the foramen are made at 80°C for 90s. A further lesion is made at the L5 dorsal ramus. Results. 4 patients achieved very good pain relief >50% reduction in pain scores on the NRS scale at 6 weeks follow up. No complications were noted and there were no technical difficulties. Conclusion. Lesioning with the NIMBUS needle is feasible and allows clinicians a method of treating chronic sacroiliac joint pain using existing radiofrequency equipment. Further large, long term studies are warranted to establish clinical efficacy

Background. Prospective study to compare patient reported outcome measures (PROM) for sacroiliac joint (SIJ) fusion using HA-coated screw (HACS) vs triangular titanium dowel (TTD). First study of its kind in English literature. Methods. 40 patients underwent percutaneous SIJ stabilisation using HACS and TTD was used in 70 patients. Patients were followed up closely and outcome scores were collected prospectively. PROMs were collected preoperatively and 12 months after surgery. Short Form (SF)-36, Oswestry Disability Index, EuroQol-5D-5L and Majeed Pelvic Scores were collected. Shapiro-wilk test was used to determine normality of data. Mann-whitney U test was used to compared non-parametric data and Independent sample T test for parametric data. Results. 33 patients in HACS group and 61 in TTD group completed follow-up. There was no significant difference in all preoperative PROMs in both groups hence the data was considered comparable. All postoperative PROMs were significantly higher in the TTD group. In the HACS group, 21 patients (63%) had lysis around the screw and a sub-group analysis showed that improvement in PROMs was significantly less in patients with lysis around the screw. 4 patients with lysis around the screw were offered revision due to ongoing pain. Revision was successful in only 1 patient. In TTD group only 5 patients (8.2 %) patients had radiological evidence of lysis. Relative risk of developing lysis was 6.7 times higher in HACS group. Conclusion. Percutaneous SIJ fixation procedure has been shown to have good clinical outcomes and TTD leads to significantly better patient reported outcomes compared to HACS. There is a 6.7 time higher risk of lysis with use of HACS and lysis is a risk factor for poor outcomes

Abstract. Background. Prospective study to compare patient reported outcome measures (PROM) for sacroiliac joint (SIJ) fusion using HA-coated screw (HACS) vs triangular titanium dowel (TTD). First study of its kind in English literature. Methods. 40 patients underwent SIJ stabilisation using HACS and TTD was used in 70 patients at CAVUHB, Cardiff. PROMs were collected prospectively before surgery and 12 months post-op. Short Form (SF)-36, Oswestry Disability Index, EuroQol-5D-5L and Majeed Pelvic Scores were collected. Shapiro-wilk test was used to determine normality of data. Mann-whitney U test was used to compared non-parametric data and Independent sample T test for parametric data. Results. 33 patients in HACS group and 61 in TTD group completed follow-up. There was no significant difference in all preoperative PROMs in both groups hence the data was considered comparable. All postoperative PROMs were significantly higher in TTD group. In HACS group, 21 patients (63%) had lysis around screw and sub-group analysis showed that PROMs were lower in patients with lysi. 4 patients with lysis around screw were offered revision due to ongoing pain. Revision was successful in only 1 patient. In TTD group only 5 patients (8.2 %) patients had radiological evidence of lysis. Relative risk of developing lysis was 6.7 times higher in HACS group. Conclusion. Percutaneous SIJ fixation procedure has good clinical outcomes and TTD leads to significantly better patient reported outcomes compared to HACS. There is a 6.7 time higher risk of lysis with use of HACS and lysis is a risk factor for poor outcomes

Crescent fractures are represented by a spectrum of morphological fracture patterns, sharing a common mechanism of injury. We propose three distinct types according to the extent of Sacroiliac (SI) joint involvement and the size of the crescent fragment, which enables a pragmatic choice of surgical approach and stabilisation technique. Crescent fractures are fracture dislocations of the SI joint in which there is variable amount of disruption of the SI ligaments extending proximally as a fracture of the posterior iliac wing. We identified three groups of Crescent fractures according to the extent of SI joint involvement, relationship of the fracture line to the S1 and S2 nerve root foramina on anteroposterior and outlet plain radiograph views, and CT films. Type I involves the less than inferior third of the SI joint with a large posterior iliac fragment left attached to the sacrum. This is best approached anteriorly for stabilisation. Type II has between one-third to two-thirds involvement of the SI joint and is treated according to Helfet's technique. Type III has a very small crescent fragment left attached to the sacrum and the inferior two-thirds of the SI joint is disrupted. This is treated with percutaneous SI screws, but will need anterior open reduction in delayed presentations. Based on this, we treated sixteen patients and followed them for at least two years. There were four Type I, four Type II and eight Type III fractures. Fifteen had anatomical reduction and stabilisation of the SI joint with good functional results. Delayed referral, the presence of significant soft tissue injury posteriorly and infected external fixator pins. From our experience we would like to propose this functional classification of crescent fractures which we find useful in making a choice of surgical approach and stabilisation technique to achieve satisfactory reduction and stabilisation of sacroiliac joint

Four patients with injuries of the acetabular triradiate cartilage are presented. In three of them premature fusion of the cartilage occurred; two of these developed acetabular deformity and subluxation of the hip. In all patients the sacroiliac joint also was injured; in two, the joint was completely disrupted, leading to fusion and growth disturbance of the ilium. As injury of the triradiate cartilage is easily missed on the initial radiograph, it is advised that all patients with pelvic trauma should be followed clinically and radiographically for at least one year

Objectives. The additive use of an external modular device may improve dorsal compression forces in pelvic external fixation. This would improve the efficiency of indirect reduction and stabilization with an anterior pelvic external fixator. The purpose of this study was to determine the forces of the posterior pelvis achieved by a new device improving the application of a supraacetabular anterior external fixator compared with other constructs. Material and Method. Synthetic pelvic models were used. Complete pelvic ring instability was created by symphyseal and unilateral sacroiliac joint disruption. Four different constructs of fixation were tested. A pressure-sensitive film was placed in the sacroiliac joint. The constructs were applied in a standardized way. The maximum sacroiliacal compression loads (N) of each trial was recorded. Statistics was performed with the student t-test. Results. Standard supraacetabular two-pin external fixator achieved a dorsal compression load of 13.84 (SD 8.13). The new dorsal pelvic compression device delivered 177.05N (SD 32.32) of load across the sacroiliac joint when the pins were inserted half way and 183.58N (SD 46.64) with full pin insertion. Both the half- and full-pin construct demonstrated a significant dorsal load improvement with the pelvic compressor (p<0.05) compared with the standard supraacetabular fixator group. The C-clamp revealed compression forces of 384.88N (SD 22.95), which was significantly greater than all the other groups (p<0.05). Conclusion. We tested a simple and new modular device for improved application of pelvic external fixation. The centres of rotation of supra-acetabular pins were determined and used to achieve greater dorsal compression forces in disrupted pelvic ring injuries. The compression load is less than with a C-Clamp, but significantly greater than the familiar technique of standard external supra-acetabular fixation. This improves the initial stability in acute management of unstable, disrupted and life threatening pelvic ring fractures

Purpose: Surgery is required for primary tumours invading the sacroiliac joint. The purpose of the present work was to analyse results obtained with surgical treatment in order to better ascertain indications. Material and methods: Forty patients (24 men and 16 women), mean age 24 years (range 12–56) underwent surgery for high-grade sarcoma (n=30, osteosarcoma 12, Ewing 13, chondrosarcoma five) or more differentiated tumours (n=10, low-grade S chondrosarcoma five, fibro-sarcoma two, others three). Resection was achieved in 37 cases via two approaches and via a lateral approach in three. Resection involved vertical sacrectomy either via the homolateral foramen (n=27) or via the midline (n=10). Reconstruction consisted in stabilising the iliosa-cral assembly generally associated with vertebral osteo-synthesis, an autologous graft in 36 cases, cement in one, and an allograft in three. Functional outcome was assessed with the MSTS (Enneking). Results: There were three infections (all three with extensive lateral approach) and five cases of postoperative lumbosacral trunk palsy. Late complications were three cases of spondylolisthesis and eight nonunions. Twenty patients died (eight local recurrences, ten metastases, one chemotherapy toxicity, one undetermined cause). Sixteen patients achieved complete remission at six years (follow-up 2–16 years) and four patients were lost to follow-up. Functional outcome was very good in eight, good in ten, fair in twelve, and poor in ten. Survival was 40% among patients with malignant tumours (38 patients) but only 20% for those with osteosarcomas. Discussion: Technical improvements (combined approach rather than wide lateral approach and omentum flap) have allowed a reduction of cutaneous and infectious complications. Mechanical complications can be prevented by systematic lumbosacral fusion on the side opposite the resection reconstruction. This provides good functional results despite sacrificing a hemi-sacral plexus if the lumbo-sacral trunk is preserved. Reconstruction after extension of the resection to the acetabulum raises an unresolved problem and yields mediocre results. The quality of the surgical resection is determinant since risk of local recurrence is 8/100 after a contaminated resection edge. Conclusion: Surgical resection of sacroiliac tumours is a source of numerous complications despite real technical improvements. This approach can be proposed if carcinological resection can be reasonably achieved. Local control is very poor in case of large osteo-osteogenic sarcomas

A prospective study was conducted to determine the functional and radiographic outcome of sacroiliac arthrodesis. Twenty patients were enrolled and the mean follow-up period was 4.6 years. SI joint instability was the most common etiology. Seventeen of twenty patients (85%) went on to a solid fusion. Statistically significant improvement was noted postoperatively in five of eight SF-36 categories (PF, RP, BP, SF, and RE), with a positive trend in the others. We conclude that sacroiliac arthrodesis is successful in the treatment of sacroiliac disorders, however its success is dependent on careful patient selection. The purpose of this study was to determine the functional and radiographic outcome of sacroiliac joint arthrodesis. Twenty consecutive patients were enrolled with an average age of 45.1 years. Plain radiographs and SF-36 Health Surveys were obtained prior to surgery and during the follow-up period. Mean duration of symptoms was 2.6 years and mean follow-up was 4.6 years. SI joint instability was the most common etiology and was present in twelve patients. Seventeen of Twenty (85%) patients went on to a solid fusion. Of the three patients who did not fuse, two remained symptomatic and required revision surgery. Fifteen of twenty patients (75%) completed pre- and post-operative SF-36 forms. Improvement was noted in all SF-36 categories. PF improved from 31.8±31.0 to 50.7±34.5 (p< 0.030). RP improved from a 0.0±0.0 to 31.3±41.5 (p< 0.012). BP improved from 15.6±11.1 to 35.7±24.7 (p< 0.009). SF improved from 37.5±21.0 to 61.5±24.1 (p< 0.028). Finally, RE improved from 46.2±48.2 to 66.7±44.9 (p< 0.012). Improvement was also noted in GH, VT, and MH from 52.2±23.5, 30.8±21.7, and 56.0±28.3, respectively to 56.1±20.5, 44.6±25.8, and 61.3±26.3, respectively, however these were not significant (p values 0.345, 0.064, and 0.220, respectively). In this prospective study, a fusion rate of 85% was achieved, and statistically significant improvement in functional outcome was observed in five of eight SF-36 categories with a positive trend in the others. Sacroiliac arthrodesis is successful in the treatment of SI joint instability, arthritis, spondyloarthropathy, and dysfunction, however, its success is dependent on careful patient selection

Dysfunction of the pelvic girdle causes alteration of the lumbopelvic muscle supporting function and thus disruption of the load transference through the pelvis. Walking loads symmetrically the muscles that provide stability to the pelvis for load transference and is an easy way to evaluate bilateral muscle function. The aim of this study was to find out if mobilisation of the symptomatic sacroiliac joint (SIJ) in chronic low back pain patients could alter the lumbopelvic muscle activity measured by surface EMG (sEMG) on the symptomatic side during walking. The resulting change in the muscle activity seemed to be relaxation of the muscles evaluated. The muscles whose activity changed for the most during walking after mobilization of the symptomatic SIJ were biceps femoris, on the right side 17,8% (p= 0.007) and on the left side 12.8% (p= 0.012). The right gluteus medius relaxed 14.4% (p=0.016) and left side 6.1% (p=0.033). Lumbar multifidi reacted more on the right side 14.5% (p=0.003) and on the left the decrease was 8.3% (p=0.021). Oblique abdominal externus muscles showed very little change after intervention. This study gives us the point of view that the main influence the mobilisation has on SIJ is neurophysiological, reflectoric on muscle tone

Purpose and background:. Sacroiliitis identified by MRI is considered as a keystone in the diagnosis of spondyloarthritis. To reduce the number of unnecessary MRI scans it would be ideal if sacroiliac (SI) joint pain provocation tests could be used to identify patients at risk of having sacroiliitis. The aim of the current study was to investigate the diagnostic value of three pain provocation SI-joint tests for sacroiliitis identified by MRI. Methods:. Patients (n=454, mean age 32 years, 54% women) without clinical signs of nerve root compression were selected from a cohort consisting of patients with persistent low back pain referred to an outpatient spine clinic. Data from the Gaenslen's Test, Thigh Thrust Test and Long Dorsal Sacroiliac Ligaments Test and sacroiliitis identified by MRI were analysed. Results:. The prevalence of SI-joints with sacroiliitis was 5%. In the whole study group, only the Thigh Trust Test was associated with sacroiliitis, ROC area 0.58 (95% CI 0.51–0.65), sensitivity 31% (18–47) and specificity 85% (82–87). In men, sacroiliitis was associated with all three SI joint tests and multitest regimens, with the greatest ROC area found for ≥ 1 positive out of 3 tests, (0.68 (0.56–0.80)), sensitivity 56% (31–79) and specificity 81% (77–85). In women, no significant associations were observed between the assessed SI joint tests and sacroiliitis. Conclusions:. Only in men were the performed SI-joint tests found to be associated with sacroiliitis identified by MRI. Although, the diagnostic value was limited, the results indicate that the use of SI joint tests for sacroiliitis may be optimised by gender-separated analyses

We reviewed 15 consecutive patients, 11 women and four men, with a mean age of 48.7 years (37.3 to 62.6), who between July 2004 and August 2007 had undergone percutaneous sacroiliac fusion using hollow modular anchorage screws filled with demineralised bone matrix.

Each patient was carefully assessed to exclude other conditions and underwent pre-operative CT and MR scans. The diagnosis of symptomatic sacroiliac disease was confirmed by an injection of local anaesthetic and steroid under image intensifier control.

The short form-36 questionnaire and Majeed’s scoring system were used for pre- and post-operative functional evaluation. Post-operative radiological evaluation was performed using plain radiographs.

Intra-operative blood loss was minimal and there were no post-operative clinical or radiological complications. The mean follow-up was for 17 months (9 to 39). The mean short form-36 scores improved from 37 (23 to 51) to 80 (67 to 92) for physical function and from 53 (34 to 73) to 86 (70 to 98) for general health (p = 0.037). The mean Majeed’s score improved from 37 (18 to 54) pre-operatively to 79 (63 to 96) post-operatively (p = 0.014). There were 13 good to excellent results. The remaining two patients improved in short form-36 from a mean of 29 (26 to 35) to 48 (44 to 52). Their persistent pain was probably due to concurrent lumbar pathology.

We conclude that percutaneous hollow modular anchorage screws are a satisfactory method of achieving sacroiliac fusion.

Introduction We report on the clinical and radiological outcomes and complications associated with percutaneous ilio-sacral screw fixation of the pelvis.

Methods Patients were located on the plevic data base held at Frenchay Hospital, Bristol, UK. Patient charts were reviewed and their clinical outcomes had been determined using a visual analogue (VAS) pain score. All patients had pre and post-operative x-rays and CT scans. These were used to determine fracture type and subsequent post-operative reduction. All complications and subsequent surgery required was noted.

Results One hundred and seven patients with 76 disruptions of the sacro-iliac joint and 62 sacral fractures treated with percutaneous ilio-sacral screws were reviewed. Average follow-up was 2.5 years (range 6 months to 8 years). Half of the patients had a VAS score of zero post-operatively, 30% had scores of one to five and 20% had scores of greater than five. The majority of these patients had a coexisting neurological lesion. Seventy-one percent had an anatomical reduction (within 5 mm), 18% had displacements of between five and 10 mm and 11% had displacements of greater than 10 mm. There were five infections, four sacral nonunions, four failures of fixation and one case of a transient L5 nerve plasy following inadvertent screw positioning.

Conclusions Percutaneous ilio-sacral screw fixation of the pelvis allows safe, reliable and accurate reduction. Poor clinical results are often attributable to coexisting neurological lesions.

Aims. There is a lack of evidence about the risk factors for local recurrence of a giant cell tumour (GCT) of the sacrum treated with nerve-sparing surgery, probably because of the rarity of the disease. This study aimed to answer two questions: first, what is the rate of local recurrence of sacral GCT treated with nerve-sparing surgery and second, what are the risk factors for its local recurrence?. Methods. A total of 114 patients with a sacral GCT who underwent nerve-sparing surgery at our hospital between July 2005 and August 2017 were reviewed. The rate of local recurrence was determined, and Kaplan-Meier survival analysis carried out to evaluate the mean recurrence-free survival. Possible risks factors including demographics, tumour characteristics, adjuvant therapy, operation, and laboratory indices were analyzed using univariate analysis. Variables with p < 0.100 in the univariate analysis were further considered in a multivariate Cox regression analysis to identify the risk factors. Results. The rate of local recurrence of sacral GCT treated with nerve-sparing surgery was 28.95% (33/114). Multivariate Cox regression analysis showed that large tumour size (> 8.80 cm) (hazard ratio (HR) 3.16; 95% confidence interval (CI) 1.27 to 7.87; p = 0.014), high neutrophil-to-lymphocyte ratio (NLR) (> 2.09) (HR 3.13; 95% CI 1.28 to 7.62; p = 0.012), involvement of a sacroiliac joint (HR 3.09; 95% CI 1.06 to 9.04; p = 0.039), and massive intraoperative blood loss (> 1,550 ml) (HR 2.47; 95% CI 1.14 to 5.36; p = 0.022) were independent risk factors for local recurrence. Conclusion. Patients with a sacral GCT who undergo nerve-sparing surgery have a local recurrence rate of 29%. Large tumour size, high NLR, involvement of a sacroiliac joint, and massive intraoperative blood loss are independent risk factors. Cite this article: Bone Joint J 2020;102-B(10):1392–1398