Anteroinferior Iliac Spine Research Articles

Intra-articular anterior inferior iliac spine avulsion with hip instability: A retrospective study

BackgroundIntraarticular anteroinferior iliac spine (AIIS) avulsion fractures combined with hip dislocation are infrequently reported in medical literature. This study aims to present the outcomes of surgical treatment for this rare type of injury. MethodsWe retrospectively analyzed six cases of AIIS avulsion fracture with hip dislocation treated surgically. All patients underwent emergency hip reduction under sedation followed by open reduction and internal fixation using 4 mm cannulated screws through the iliofemoral approach. ResultsAfter an average follow-up period of 50 months, all fractures healed. Clinically, four patients were rated as having an excellent outcome and two as good, according to the Harris Hip Score. Radiological assessment using Matta's grading system showed excellent results in five patients and good in one. All patients were able to resume their pre-injury activity levels within six months post-surgery. ConclusionSurgical fixation of AIIS avulsion fractures with associated hip instability demonstrates favourable outcomes, ranging from good to excellent, in both clinical and radiological assessments at medium-term follow-up. This suggests that surgical intervention is a viable option for managing such injuries.

Surgical management of iliac wing fractures: Proposal of a new classification system

IntroductionIsolated fractures of the iliac wing are a rare injury, usually occurring in high-energy trauma, and are associated with other non-musculoskeletal and soft tissue injuries that could compromise the patient's life. Surgical indications are unclear, and there is limited information on the most frequent fracture patterns. MethodsA descriptive multicenter case series study of isolated fractures of the iliac wing treated surgically in three referral trauma hospitals in Latin America. The different fracture patterns are described, the "iliac ring" concept is proposed, and a classification is made. ResultsTwenty-eight patients were included; 24 were male, the median age was 31 years RIQ (24–46), the most frequent trauma mechanism was a traffic accident, and in 14 patients, the ISS >16. The most frequent associated injury was to the appendicular skeleton at another level in 13 patients. In the new classification, according to the number of fragments, 11 patients were classified as type A (1 fragment), ten patients as type B (two fragments), and seven patients as type C (three or more fragments). The most compromised anatomical area was the crest and anterosuperior iliac spines in 26 patients, followed by the fossa and anteroinferior iliac spine in 17 and 8 patients, respectively. DiscussionThe patterns of isolated fractures of the iliac wing allow the identification of three types of fractures. Identifying these patterns can help the surgeon decide to perform surgery in these scenarios and choose the fixation technique according to the number and location of the fragments.

A retrospective CT based comparative analysis of available screw pathways to determine optimal iliac screw trajectory

<b>Introduction:</b> The lumbo-sacral stabilization using iliac screw is gaining popularity in such cases of long multi segment lumbar constructs. Iliac screws help to achieve strong spinopelvic fixation, augments and protects sacral screws. However, there is a great variability found in literature for iliac screw fixation in terms of trajectory, screw length and screw diameter. Also, to the best of our knowledge, there is lacunae in current literature regarding the optimal pathway, screw length and screw diameter in the Indian population. Hence, we planned the study with the aim to analyze the available screw pathways to determine optimal iliac screw trajectory, screw length and diameter for the Indian population.<br /> <b>Material and methods:</b> This was a tertiary center-based retrospective study. One hundred pelvic CT scans of patients in 18-70 years age, who underwent abdominal CT on Siemens 256-slice dual source CT scanner for various indications were evaluated. Subsequently, 4 iliac screw trajectories were assessed by connecting the points given below using double oblique reformats on which the lengths and narrowest zones of these trajectories were measured. Path A: Posterior Superior Iliac Spine (PSIS) to Anterior Superior Iliac Spine (AIIS); Path B: point between PSIS and posterior inferior iliac spine (PIIS) to Anterior Inferior iliac spine  (AIIS); Path C: iliac crest intersection point (CLIC) point to Upper acetabulum; Path D: CLIC point to acetabular center.<br /> [p1] <b>[a2] Results:</b> Statistically significant difference was found in the lengths of various pathways. Path A (PSIS to AIIS) was found to be the longest (mean 13 cm). The second longest path in our study was path C (CLIC point to Upper acetabulum). The narrowest widths of each path were not found to have any statistically significant difference.<br /> <b>Conclusion:</b> Iliac screw fixation is of paramount importance for lumbosacral stabilization. Of the studied paths, trajectory from posterior-superior iliac spine to Antero-inferior iliac spine has the longest passage length and is the most optimal path for the Indian population. In case additional screws are required, the trajectory from CLIC point to Upper acetabulum provides the second largest screw passage.

Subspine femoroacetabular impingement: retrospective study of a series of patients treated by hip arthroscopic resection

BackgroundFemoroacetabular impingement syndrome (FAIS) is a common hip pathology that causes pain and functional limitation in young patients. subspine femoroacetabular impingement (SFAI) is an increasingly diagnosed extra-articular subtype that occurs from mechanical conflict of the anteroinferior iliac spine (AIIS) with the cervico-diaphyseal junction during hip flexion, which is poorly described in the literature.Questions/purposesWe aimed to describe the clinical, functional, and radiological results of the arthroscopic treatment of a group of patients with SFAI treated in our Hip Unit.Study designCase series.MethodsWe present a retrospective study of ten patients with SFAI treated between 2013 and 2020 with arthroscopic resection. Clinical results were assessed with scales such as visual analog scale (VAS); modified Harris Hip Score (mHHS), and Hip disability and Osteoarthritis Outcome Score (HOOS). Radiological results were assessed with radiological measurements, magnetic resonance imaging (MRI), and computed tomography (CT) reconstructions.ResultsSix patients had a Type III AIIS and four of them had Type II. Two patients had previously been surgically treated for FAIS. The range of motion improved in flexion from 107 ± 11 degrees before surgery to 127.5 ± 6 degrees (p = 0.005). MHHS improved from 48.1 (38–75.3) before surgery to 83.1 (57–91) (p = 0.007) and HOOS improved from 65.2 (58–75) to 89 (68.1–100) (p = 0.007). VAS improved from 7.3 (5–9) pre-surgical to 2.5 (0–8) post-surgical (p = 0.005). We did not have significant complications except for an asymptomatic case of heterotopic ossification (Brooker I).ConclusionArthroscopic decompression of AIIS in SFAI patients is a safe procedure that provides satisfactory short-term functional results, improving clinical symptoms, function, sports performance, and range of motion in our study.

Open technique for supra-acetabular pin placement in pelvic external fixation: a cadaveric study

BackgroundStandard supra-acetabular pin placement still needs fluoroscopic guidance, which is technically demanding for an untrained surgeon due to the unfamiliar fluoroscopic view and the risk of damaging some structures. The risks associated with the open technique without fluoroscopy have not yet been investigated, despite the palpable entry point and large bony corridor for rapid insertion in the limited time available for the management of unstable pelvic fracture patients. The aim of this study was to compare the open technique without fluoroscopy to the fluoroscopically assisted percutaneous technique for the positioning of supra-acetabular screws in cadavers without pelvic instability.Materials and methodsThe open technique for half-pin placement was compared to standard fluoroscopic guidance in 16 hemipelves (8 cadavers). The open technique was first performed on one side in each cadaver after simple randomization, followed by standard fluoroscopic guidance on the other side. In the open technique group, a Schanz pin 5 mm in diameter and 200 mm in length was inserted in the area just above the anteroinferior iliac spine (AIIS) and aimed with a medial inclination of 20° and a cephalad inclination of 10–20° after a 2 cm pilot drill hole had been established. Standard fluoroscopically guided pin placement was performed on the other side. Fluoroscopic assessment was conducted after final pin placement on both sides. The lateral femoral cutaneous nerve of the thigh (LFCN) and the hip capsule were identified via the Smith–Peterson approach. After complete dissection of soft tissue, it was clearly apparent that pin penetration was conducted outside the bony corridor.ResultsThe LFCN was found to be in a risk zone near the pin (mean distance, 15 mm; range, 0–30 mm). One LFCN may have been injured in the fluoroscopic guidance group. The mean medial inclination of the pin was 19.8° (range, 5–40°) and the mean cephalad inclination was 11.5° (range 0–20°) in the open technique group. The mean medial inclination of the pin was 30.4° (range, 20–45°) and the mean cephalad inclination was 19.3° (range, 2–35°) in the fluoroscopic guidance group. The mean distance of the pin entry point from the AIIS was 11.1 mm (range, 0–35 mm) in the open technique group. The mean distance of the entry point of the pin from the AIIS was 15.1 mm (range, 0–25 mm) in the fluoroscopic guidance group. The mean hip joint capsule distance was 12 mm (range, 8–25 mm). No joint penetration was observed in the open technique group, compared to one joint penetration in the fluoroscopic guidance group. No sciatic notch penetration was found in either group, but pin penetration outside the external cortex of the ilium was found only in the open technique group, in 4 hemipelves.ConclusionsThis study shows that the freehand technique performed by experienced trauma surgeons may be as acceptable as controlled pin insertion under image intensification for selecting the proper entry point and stabilizing the anterior pelvic ring.

The case of 'A Rhino Horn': case report and proposal for modification to the Hetsroni and Kelly classification.

Subspine impingement syndrome by definition involves a prominent antero-inferior iliac spine (AIIS) which can lead to impingement on the femoral neck thereby causing symptoms. We present the case of a 22-year-old semi-professional athlete who presented with a Type III AIIS morphology leading to subspine impingement syndrome and was managed via a mini open anterior approach. Radiological examination revealed a fairly prominent left AIIS resembling the ‘horn of a rhino’ extending to the trochanteric region anteriorly. A mini-anterior surgical approach was utilized for the resection of the ‘rhino horn’ and the rectus femoris was reattached. The patient remained asymptomatic at the one-year follow-up and had resumed weightlifting. Following this case, we propose a new classification of the type III AIIS morphology in view of the clinical presentation. The AIIS type III-Standard represents an extension from the acetabular rim to less than 1 cm (type III-S) and type III-Large, with an extension from the acetabular rim beyond 1 cm (type III-L). The type III-L will further be divided into two groups based on its relation to the ilium, type III-Lr (‘rib shape’) and type III-Lrh (‘rhino horn’).

Hip apophyseal injuries in soccer players: can MRI findings be useful to define when to return to play?

To describe magnetic resonance imaging (MRI) findings in professional soccer players with acute apophyseal injury of the hip and to assess their relationship with return to sports. Adolescent soccer players with diagnosis of apophyseal injury in the anterosuperior and anteroinferior iliac spine were retrospectively evaluated between 2008 and 2016. All athletes underwent hip MRI examination within 4days after onset of clinical complaint. Images were independently analyzed by two radiologists. Medical records were reviewed to obtain clinical data. Mean displacement of the apophysis was 4.8 ± 4.6mm. Bone edema was present in 82% of athletes and muscular edema in 41%. The mean time to return to sports was 37.3 ± 14.7days. The difference between the measurements of the two radiologists was close to zero with agreement limits below 1.0mm (p < 0.001). There was a significant correlation between displacement of the apophysis and return to sports, as well as between both and the presence of muscular edema. A displacement of the apophysis of 3.0mm might serve as a parameter to predict return to sports/activity before 40days, with a sensitivity of 92% and specificity of 96%, considering conservative physiotherapy treatment. Displacement of the apophysis and presence of muscular edema evaluated by MRI showed a significant correlation with return to sports in athletes with acute apophyseal injuries of the anterosuperior and anteroinferior iliac spines.

Three ways of inserting the anteroinferior iliac spine channel screws: a computer simulation comparison

Objective To compare the safely between 3 ways of inserting the anteroinferior iliac spine channel screws using computer simulation. Methods The spiral pelvic CT data of 100 patients were collected who had sought medical treatment at General Hospital of The Northern Theater Command from October 2017 to October 2018. They were 61 males and 39 females, aged from 20 to 60 years (average, 47.5 years). The data were imported into Mimics (Materi-alise, Belgium) software to create three-dimensional models of the pelvis. The pelvic modeling data were then imported into 3-Matic (Materi-alise, Belgium) software for post-processing. Three cylinders with a diameter of 6.7 mm were created, taking the anteroinferior iliac spine as the entry point and taking the posterosuperior iliac spine, the posteroinferior iliac spine and the midpoint between the 2 spines as the 3 exit points. The insertion of anteroinferior iliac spine channel screws was simulated to observe the screw penetration. Results In the channel from the anteroinferior iliac spine to the posterosuperior iliac spine, penetration occurred in 41 cases out of the medial ilium and in 2 cases out of the lateral ilium, giving a penetration rate of 43% (43/100); in the channel from the anteroinferior iliac spine to the midpoint between the 2 spines, penetration occurred in 16 cases out of the medial ilium and in 2 cases out of the lateral ilium, giving a penetration rate of 18% (18/100); in the channel from the anteroinferior iliac spine to the posteroinferior iliac spine, penetration occurred in 6 cases out of the medial ilium, in 2 cases out of the lateral ilium, in 60 cases out of the greater sciatic notch and in 8 cases out of both the medial ilium and greater sciatic notch, giving a penetration rate of 76% (76/100). There were significant differences between the 3 ways of insertion in the screw penetration (χ2=68.219, P<0.001). The rate of screw penetration in the channel from the anteroinferior iliac spine to the posteroinferior iliac spine was significantly higher than that in the channel from the anteroinferior iliac spine to the posterosuperior iliac spine which was significantly higher than that in the channel from the anteroinferior iliac spine to the midpoint between the 2 spines (P<0.05). Conclusions The channel from the anteroinferior iliac spine to the midpoint between the posterosuperior iliac spine and the posteroinferior iliac spine may lead to a lower rate of screw penetration while the channel from the anteroinferior iliac spine to the posteroinferior iliac spine may lead to a higher rate of screw penetration. Key words: Pelvis; Bone nails; Safe passage; Morphology

Computational simulation of sacral-alar-iliac (S2AI) screw fixation of pelvis and implications for fluoroscopic procedure: A cadaver study.

To determine an easy and convenient method of sacral-alar-iliac (S2AI) screw fixation and introduce the surgical landmarks for fluoroscopic procedure by analyzing 3-D models of pelvis and virtual implantation in a 3-D model. Eighty-two cadavers underwent computed tomography scans and the images imported into Mimics® software to make the 3-D pelvis model. The pedicle screw (Ø 8.5 mm/length 115 mm) was processed into a 3-D model using a 3-D-sensor (Comet5®) at the actual size and virtually placed as the S2AI screw. The ideal screw position was defined as the maximal intraosseous length without cortical perforation along the entire path. The ideal entry point and screw trajectory were verified and assessed to introduce the surgical landmark for fluoroscopic procedure. There was no cortical violation around nerve root canal and greater sciatic notch through the entry point between first and second dorsal sacral foramen. There was no impossible model of S2AI screws. The average screw length was 99.8 mm (range, 59.8-115 mm; standard deviation, 16.1) and just one model had shorter than 65 mm S2AI screw. The factors limiting the intra-iliac screw length were sex ( p = 0.000) and the iliac groove around the sacroiliac joint ( p = 0.000). A free 360° rotation with magnification revealed that the screw trajectory was consistently directed toward the anteroinferior iliac spine (AIIS) in any plane. The ideal entry point of S2AI screw showed a wide range of tolerance between the first and second dorsal sacral foramen; and thus, there was no need for deep dissection to identify the first dorsal sacral foramen. Considering the tendency to shift the pilot hole laterally and the ideal screw trajectory was consistently directed toward AIIS, the entry point is better to be located with a medial shift.

Minimally invasive surgical treatment using 'iliac pillar' screw for isolated iliac wing fractures in geriatric patients: a new challenge.

There have been no prior case series of isolated iliac wing fracture (IIWF) due to low-energy trauma in geriatric patients in the literature. The aim of this study was to describe the characteristics of IIWF in geriatric patients, and to present a case series of IIWF in geriatric patients who underwent our minimally invasive screw fixation technique named 'iliac pillar screw fixation'. We retrospectively reviewed six geriatric patients over 65 years old who had isolated iliac wing fracture treated with minimally invasive screw fixation technique between January 2006 and April 2016. Six geriatric patients received iliac pillar screw fixation for acute IIWFs. The incidence of IIWFs was approximately 3.5% of geriatric patients with any pelvic bone fractures. The main fracture line exists in common; it extends from a point between the anterosuperior iliac spine and the anteroinferior iliac spine to a point located at the dorsal 1/3 of the iliac crest whether fracture was comminuted or not. Regarding the Koval walking ability, patients who underwent iliac pillar screw fixation technique tended to regain their pre-injury walking including one patient in a previously bedridden state. The visual analog scale score for pain at the last follow-up was quite satisfactory. Union was achieved in all patients at the last follow-up. Geriatric patients can have a form of IIWF caused by low-energy trauma that is a type of fragility fracture of the pelvis. Because subsequent deterioration of their walking status followed by a long period of non-weight bearing in geriatric patients could be as threatening as the fracture itself, the treatment paradigm for IIWF due to low-energy trauma in geriatric patients should differ from that due to high-energy trauma in most patients. In these types of fractures, minimally invasive surgical management that includes iliac pillar screw fixation can lead to good outcomes.

Imaging of rectus femoris proximal tendinopathies.

The rectus femoris is the most commonly injured muscle of the anterior thigh among athletes, especially soccer players. Although the injury pattern of the muscle belly is well documented, less is known about the anatomy and specific lesions of the proximal tendons. For each head, three distinctive patterns may be encountered according to the location of the injury, which can be at the enthesis, within the tendon, or at the musculotendinous junction. In children, injuries correspond most commonly to avulsion of the anteroinferior iliac spine from the direct head and can lead to subspine impingement. Calcific tendinitis and traumatic tears may be encountered in adults. Recent studies have shown that traumatic injuries of the indirect head may be underdiagnosed and that injuries of both heads may have a surgical issue. Finally, in the case of tears, functional outcome and treatment may vary if the rupture involves one or both tendons and if the tear is partial or complete. Thus, it is mandatory for the radiologist to know the different ultrasound and magnetic resonance imaging (MRI) patterns of these lesions in order to provide accurate diagnosis and treatment. The purpose of this article is to recall the anatomy of the two heads of rectus femoris, describe a reliable method of assessment with ultrasound and MRI and know the main injury patterns, through our own experience and literature review.

Low femoral antetorsion as a risk factor for bony impingement after bipolar hemiarthroplasty.

IntroductionReports of dislocation after bipolar hemiarthroplasty (BHA) abound in literature, and several studies have mentioned the factors that are associated with an increased risk of dislocation. However, there is no report detailing the pattern of impingement in BHA and how femoral antetorsion can affect the range of motion (ROM) after BHA.PurposeThe purpose of this study was to evaluate the pattern of impingement in BHA and whether femoral antetorsion affects the ROM after BHA using three-dimensional (3D) dynamic motion analysis.MethodsUsing the computed tomography (CT) data of 60 patients (60 hips), including 31 men and 29 women who underwent BHA for the treatment of idiopathic osteonecrosis (ION) of the femoral head, we calculated the antetorsion of the femoral neck, ROM of flexion (Flex), internal rotation (Int-R), and external rotation (Ext-R) using a CT-based 3D simulation software. We evaluated the pattern of impingement and the relationship between femoral antetorsion and ROM in BHA. As for the implant position in the 3D simulation software, the anteversion of the femoral implant was set to be the same as the natural antetorsion of the femoral neck and neck length was set to be the standard neck in all cases.ResultsThis study revealed the mechanism of impingement in BHA: (1) bone to bone impingement and (2) implant to bone impingement. We found a significant decrease in the ROM of Flex and Int-R inversely proportional to the femoral antetorsion. In patients with lower femoral antetorsion, the ROM of Flex and Int-R decreased due to bony impingement (the anterior great trochanteric region of the femur impinges on the anteroinferior edge of the anteroinferior iliac spine). Whereas, high anteversion of the femoral implant may decrease the ROM of Ext-R; however, our results also showed that even the lowest ROM of Ext-R with 10° hip extension was over 40°.ConclusionsWe demonstrated that lower femoral antetorsion substantially affects the ROM of Flex and Int-R due to bony impingement. For these patients, there should be consideration given to retaining femoral “anterior offset” in BHA.

Effect of Subspine Decompression on Rectus Femoris Integrity and Iliopsoas Excursion: A Cadaveric Study

To determine the relative influence of anteroinferior iliac spine (AIIS) or subspine decompression on proximal rectus femoris integrity and iliopsoas excursion throughout a physiological range of motion. Nineteen cadaveric hips from 10 specimens were dissected to retain the origin of the rectus femoris direct and indirect heads. The anatomic footprints of the origins were measured with calipers. Serial 5-mm resections of the AIIS were made to determine the extent of proximal tendon disruption that corresponded to each resection. Iliopsoas tendon tracking was also assessed after sequential AIIS decompression by measuring the excursion of the medial border of the iliopsoas tendon as it traveled from its native resting position to the point where it first encountered bony impingement at the AIIS. The mean proximal-distal footprint of the rectus femoris direct head was 17.95 ± 2.99 mm. The mean medial-lateral distance was 11.84 ± 2.34 mm. There was a consistent bare area along the inferior aspect of the AIIS that averaged 4.84 ± 1.42 mm. The average percentage of remaining footprint after each 5-mm resection (5 to 25 mm) was96%, 65%, 35%, 14%, and 11%, respectively, with statistical significance noted after resections larger than 5 mm (P< .001). The native excursion distance of the iliopsoas tendon was 14.05 mm. With each 5-mm resection, the percentage of excursion before impingement on the AIIS increased by 18%, 45%, 72%, 95%, and 100%, respectively, which was statistically significance after all resections (P < .001). Our study maps the anatomic footprint of the direct head of the rectus femoris tendon and confirms a previously identified bare area along the inferior aspect of the AIIS. Female cadaveric hips had a significantly smaller rectus footprint than male cadavers in our study (P < .001). Subspine decompression greater than 10 mm significantly compromises the rectus femoris origin and should be avoided when performing arthroscopic AIIS decompression. In addition, subspine decompression significantly improves tracking of the iliopsoas tendon throughout a physiological range of motion and may be considered a surgical adjunct when treating symptomatic iliopsoas snapping. Arthroscopic subspine decompression serves as an important treatment modality for AIIS impingement. With a more thorough understanding of AIIS anatomy, subspine decompression can be used to relieve impingement symptoms and possibly improve iliopsoas tracking while safely maintaining rectus femoris footprint integrity.

Effect of Subspine Decompression on Rectus Femoris Integrity and Iliopsoas Excursion: A Cadaveric Study

Effect of Subspine Decompression on Rectus Femoris Integrity and Iliopsoas Excursion: A Cadaveric Study

Rapid development of osteoarthritis following arthroscopic resection of an “os acetabuli” in a mildly dysplastic hip—a case report

A 42-year-old athletic woman attended our clinic complaining of right groin pain. The pain had begun 2 years previously when jogging. The pain had gradually become worse, limiting her daily activities and any sporting activities. Clinical examination showed a positive impingement test and limitation of internal rotation of up to 20o at 90o of hip flexion. Plain radiogrpahs showed a normal alpha angle, and a 12 × 14 mm “os acetabuli” was present at the superolateral acetabular rim (Figure 1). The joint was mildly dysplastic with a center-edge angle (CEA) (excluding the “os acetabuli”) of 15o (25o in the contralateral hip). The Tonnis angle was 24o. Differential diagnoses were an “os acetabuli” in a dysplastic hip, chronic avulsion fracture of de anteroinferior iliac spine (Larson et al. 2011), stress fracture (Martinez et al. 2006), or enchondroma-like lesion. The CT described the presence of an “os acetabuli” beside the joint surface with an intact anteroinferior iliac spine (Figure 2). Figure 1. Plain AP (A) and lateral view (B) showing a normal alpha angle. A 12 × 14 mm calcified irregular-shaped image was seen at the superolateral acetabular rim. Excluding the “os acetabuli”, the center-edge angle was 15o (25o ... Figure 2. Sagittal plane CT scan image optimized for bone density, showing the “os acetabuli” (arrow). The patient’s pain persisted, and we made a hip arthroscopy. She was placed supine on the traction table. Due to the shape, size, and location of the lesion, access to the central compartment was difficult and an “outside-in” technique with a T-shaped capsulotomy was performed (Horisberger et al. 2010, Cuellar et al. 2013). Dynamic intraoperative assessment showed impingement between the “os acetabuli” and the superior labrum, which was slightly frayed and detached from the acetabulum (Figure 3). The bony lesion was dissected and resected, keeping the underlying labrum intact. The labrum was reinserted with three 2.3-mm Bioraptor bone anchors (Smith and Nephew). The capsule was then repaired with interrupted Ultrabride sutures, with 2 side-to-side sutures. No femoral osteochondroplasty was performed. Figure 3. View of the peripheral compartment from the anteromedial portal with a 30o scope. The close relation between the detached labrum (L) and the “os acetabuli” (O) can be seen. F: femoral head. After surgery, the patient was instructed not to bear weight for 4 weeks and then to resume partial weight bearing for another 4 weeks. Hyperextension was restricted for the first 3 months, to protect capsular healing. At 4-month follow-up, the patient was walking unaided and was free from pain; she had a full range of motion and radiographs confirmed the complete resection of the “os acetabuli”—but a slight joint narrowing was detected. At 6-month follow-up, she had again developed groin pain. At 10 months, radiographs showed a Tonnis-III degenerative stage (Figure 4). A total hip replacement was required at 12 months. During the joint replacement, we found osteoarthritis and a reduction of femoral head coverage. Figure 4. A. At 4-month follow-up, complete resection of the “os acetabuli” and a slight narrowing of the joint space. B. At 10-month follow-up anterosuperior subluxation and clear degenerative joint disease with sclerotic joint line and subchondral ...

Low femoral antetorsion and total hip arthroplasty: a risk factor.

The purpose of this study was to evaluate whether femoral antetorsion affects the range of motion (ROM) following total hip arthroplasty (THA) using 3D dynamic analysis. Using 3D computed tomography (CT) data of 71 patients (71 hips) who underwent THA, we calculated antetorsion of the femoral neck, flexion range of motion (Flex ROM), internal rotation (Int-R) and external rotation (Ext-R). Evaluation of the relationship between antetorsion, ROM and the impingement site was performed. As for implant position, anteversion of the femoral implant was set to be the same as natural antetorsion of the femoral neck, and the acetabular component was set 45° of total anteversion in all cases. We found a significant decrease in Flex ROM and Int-R inversely proportional to femoral antetorsion. In patients with lower antetorsion, Flex ROM and Int-R decreased due to bony impingement (the anterior great trochanteric region of the femur impinges on the anteroinferior edge of the anteroinferior iliac spine). However, in Ext-R, there was no relationship between ROM and femoral antetorsion. We demonstrated that lower femoral antetorsion substantially affects Flex ROM and Int-R due to bony impingement. For these patients, consideration must be given to retaining femoral anterior offset in THA.

Bony impingement depends on the bone morphology of the hip after total hip arthroplasty

The purpose of this study was to evaluate whether the bone morphology of the hip affects the range of motion (ROM) in total hip arthroplasty (THA). Using the CT data of 63 patients who underwent THA, we calculated the ROM of flexion (Flex), internal rotation (Int-R) and external rotation (Ext-R) using 3D dynamic analysis software. We measured the distance between the anterior surface of the stem and anterior aspect of the greater trochanter (GTa length) at the cutting point and between the tip of the antero-inferior iliac spine (AIIS) and coronal plane of both femoral heads (AIIS length), as a parameter of the femur and pelvis, respectively. The relationship between the ROM, bone anatomy and impingement site was evaluated. We found a significant decrease in the ROM of Flex and the Int-R to be inversely proportional to the GTa and AIIS length. In Flex and Int-R, the anterior intertrochanteric region often impinges on the AIIS in patients with larger bone anatomy. We demonstrated that the bone morphology of the hip substantially affects the ROM of Flex and Int-R, especially in patients with large bone anatomy. For these patients we should consider bony impingement in THA.

A safe technique of anterior column lag screw fixation in acetabular fractures

Conventional anterior column lag screw fixation in acetabular fracture is a difficult technique that has potential risks of vascular injury, hip joint penetration and excessive radiation exposure. We propose a safe technique of anterior column lag screw fixation (in-out-in technique) and present the outcome. Twenty-seven acetabular fractures were operated through an iliofemoral approach, where the 'in-out-in technique' of lag screw fixation was a part of the surgical procedure. The technique involved insertion of a malleolar screw (4.5 mm) or 6.5 mm partially threaded cancellous screw from the outer side of the iliac wing, 0.5-1 cm posterior and inferior to the anteroinferior iliac spine. The screw comes out of the bone surface to re-enter into the anterior part of iliopectineal eminence, and finally gains purchase in the lateral part of superior pubic ramus. The screw fixation procedure was under direct visualization without resorting to an image intensifier. The average follow-up of the patients was at 18.6 months (range 12-36 months). No loss of reduction, joint penetration or visceral and neurovascular injury were documented. The average duration of surgery was 70 min and blood loss was 290 ml. All fractures were united after an average period of 2.8 months. Excellent to good functional outcome was observed in 24 patients (88 %), on evaluation with Merle D'Aubigne and Postel score at the latest follow-up. We conclude that the 'in-out-in technique' is a safe and effective method of anterior column lag screw fixation in acetabular fractures. It provides rigid stability and minimizes surgical duration, radiation exposure and intra-operative complications.

Adolescent Femoroacetabular Impingement From Malunion of the Anteroinferior Iliac Spine Apophysis Treated With Arthroscopic Spinoplasty

This article describes a case of an acute anterior inferior iliac spine apophyseal avulsion fracture in an adolescent athlete progressing to secondary symptomatic femoroacetabular impingement from an inferiorly displaced malunion and its arthroscopic management. A 13-year-old boy with an acute minimally displaced avulsion fracture of the anterior inferior iliac spine apophysis had initial symptomatic improvement with conservative treatment and a 3-month symptom-free period but then developed flexion-induced deep anterior groin pain and mechanical symptoms. Radiographs confirmed an inferiorly displaced malunion of the ipsilateral anterior inferior iliac spine apophysis in addition to acetabular retroversion and cam deformity. Surgical treatment, including arthroscopic spinoplasty, was performed. Despite some nonrestrictive heterotopic ossification, the patient had a successful clinical outcome at 18 months, with return to football, and a nonarthritic hip score of 98. Although anterior inferior iliac spine avulsion fractures have historically been considered relatively self-limiting injuries, their malunion may be a previously missed cause of unrelenting or bimodal pain from secondary femoroacetabular impingement with possible degenerative consequences in young athletic patients. Anterior inferior iliac spine avulsion fractures may merit a lower degree of tolerance for displacement in the acute setting and a higher degree of clinical and radiographic scrutiny with surgical intervention, possibly in the form of arthroscopic spinoplasty in the more chronic one.

The Use of a Biplanar Construct in Pelvic External Fixation

Inserting pins at a single location of the iliac crest temporarily provides an effective splint for emergency patients with pelvic ring fractures. For a longer application, however, this procedure frequently causes infection and pin loosening and does not effectively stabilize the pelvic construct. We presumed biplanar pelvic constructs may provide better stability than a uniplanar construct. Two patients were treated with inserting pins at the lateral side of the supra-acetabulum as well as the iliac crest. Postoperatively, they demonstrated significant improvement in pain relief. The biplanar pelvic constructs showed sufficient stability during the procedure and at the time of pin removal several months postoperatively. Another pinning location for pelvic external fixation is the anteroinferior iliac spine toward the posteroinferior iliac spine. Inserting pins from this spot and the iliac crest does not create a biplanar construct, since anatomically these pins share a similar plane. Thus, the biplanar method in which pins were introduced at the lateral side of the supra-acetabulum and at the iliac crest was selected. Despite the pins' application for several months, pin-site infection was not critical in our cases. We concluded that stability of the biplanar construct helped minimize pin-site infection.