Femoroacetabular impingement is a cause of hip pain in adults and is potentially a precursor of osteoarthritis. Our aim in this study was to determine the prevalence of bilateral deformity in patients with symptomatic cam-type femoroacetabular impingement as well as the presence of associated acetabular abnormalities and hip pain. We included all patients aged 55 years or less seen by the senior author for hip pain, with at least one anteroposterior and lateral pelvic radiograph available. All patients with dysplasia and/or arthritis were excluded. A total of 113 patients with a symptomatic cam-impingement deformity of at least one hip was evaluated. There were 82 men and 31 women with a mean age of 37.9 years (16 to 55).

Bilateral cam-type deformity was present in 88 patients (77.8%) while only 23 of those (26.1%) had bilateral hip pain. Painful hips had a statistically significant higher mean alpha angle than asymptomatic hips (69.9° vs 63.1°, p < 0.001). Hips with an alpha angle of more than 60° had an odds ratio of being painful of 2.59 (95% confidence interval 1.32 to 5.08, p = 0.006) compared with those with an alpha angle of less than 60°. Of the 201 hips with a cam-impingement deformity 42% (84) also had a pincer deformity.

Most patients with cam-type femoroacetabular impingement had bilateral deformities and there was an associated acetabular deformity in 84 of 201 patients (42%). This information is important in order to define the natural history of these deformities, and to determine treatment.

Slipped capital femoral epiphysis (SCFE) may lead to symptomatic femoroacetabular impingement (FAI). We report our experience of arthroscopic treatment, including osteochondroplasty, for the sequelae of SCFE.

Data were prospectively collected on patients undergoing arthroscopy of the hip for the sequelae of SCFE between March 2007 and February 2013, including demographic data, radiological assessment of the deformity and other factors that may influence outcome, such as the presence of established avascular necrosis. Patients completed the modified Harris hip score (mHHS) and the non-arthritic hip score (NAHS) before and after surgery.

In total, 18 patients with a mean age of 19 years (13 to 42), were included in the study. All patients presented with pain in the hip and mechanical symptoms, and had evidence of FAI (cam or mixed impingement) on plain radiographs.

The patients underwent arthroscopic osteoplasty of the femoral neck. The mean follow-up was 29 months (23 to 56).

The mean mHHS and NAHS scores improved from 56.2 (27.5 to 100.1) and 52.1 (12.5 to 97.5) pre-operatively to 75.1 (33.8 to 96.8, p = 0.01) and 73.6 (18.8 to 100, p = 0.02) at final follow-up, respectively. Linear regression analysis demonstrated a significant association between poorer outcome scores and increased time to surgery following SCFE (p < 0.05 for all parameters except baseline MHHS).

Symptomatic FAI following (SCFE) may be addressed using arthroscopic techniques, and should be treated promptly to minimise progressive functional impairment and chondrolabral degeneration.

Take home message: Arthroscopy of the hip can be used to treat femoroacetabular impingement successfully following SCFE. However, this should be performed promptly after presentation in order to prevent irreversible progression and poorer clinical outcomes.

Cite this article: Bone Joint J 2016;98-B:21–7.

Hip and groin injuries are common in athletes who take part in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion of the tendons attached to the symphysis pubis has previously been described: these can be managed both operatively and non-operatively. We describe an uncommon variant of this injury, namely complete avulsion of the adductor sleeve complex: this includes adductor longus, pectineus and rectus abdominis. We go on to describe a surgical technique which promotes a full return to the pre-injury level of sporting activity.

Over a period of ten years, 15 high-level athletes with an MRI-confirmed acute adductor complex avulsion injury (six to 34 days old) underwent surgical repair. The operative procedure consisted of anatomical re-attachment of the avulsed tissues in each case and mesh reinforcement of the posterior inguinal wall in seven patients. All underwent a standardised rehabilitation programme, which was then individualised to be sport-specific.

One patient developed a superficial wound infection, which was successfully treated with antibiotics. Of the 15 patients, four complained of transient local numbness which resolved in all cases. All patients (including seven elite athletes) returned to their previous level of participation in sport.

Cite this article: Bone Joint J 2015;97-B:1488–92.

Objectives

Sagittal alignment of the lumbosacral spine, and specifically pelvic incidence (PI), has been implicated in the development of spine pathology, but generally ignored with regards to diseases of the hip. We aimed to determine if increased PI is correlated with higher rates of hip osteoarthritis (HOA). The effect of PI on the development of knee osteoarthritis (KOA) was used as a negative control.

Open reduction of the prominence at the femoral head-neck junction in femoroacetabular impingement has become an established treatment for this condition. We report our experience of arthroscopically-assisted treatment of femoroacetabular impingement secondary to paediatric hip disease in 14 hips in 13 consecutive patients (seven women, six men) with a mean age of 30.6 years (24 to 39) at the time of surgery. The mean follow-up was 2.5 years (2 to 4).

Radiologically, 13 hips had successful restoration of the normal geometry and only one had a residual deformity. The mean increase in the Western Ontario McMasters Osteoarthritis Index for the series at the last follow-up was 9.6 points (4 to 14). No patient developed avascular necrosis or sustained a fracture of the femoral neck or any other complication.

These findings suggest that femoroacetabular impingement associated with paediatric hip disease can be treated safely by arthroscopic techniques.

We performed a retrospective examination of the anteroposterior pelvic CT scout views of 419 randomly selected patients between April 2004 and August 2009 in order to determine the prevalence of cam-type femoroacetabular deformity in the asymptomatic population. The CT scans had all been undertaken for conditions unrelated to disorders of the hip. The frequency of cam-type femoroacetabular deformity was assessed by measuring the α-angle of each hip on the anteroposterior images. The α-angles were classified according to the Copenhagen Osteoarthritis Study. Among 215 male hips (108 patients) the mean α-angle was 59.12° (37.75° to 103.50°). Of these, a total of 30 hips (13.95%) were defined as pathological, 32 (14.88%) as borderline and 153 (71.16%) as normal. Among 540 female hips (272 patients) the mean α-angle was 45.47° (34.75° to 87.00°), with 30 hips (5.56%) defined as pathological, 33 (6.11%) as borderline and 477 (88.33%) as normal. It appears that the cam-type femoroacetabular deformity is not rare among the asymptomatic population. These anatomical abnormalities, as determined by an increased α-angle, appear to be twice as frequent in men as in women. Although an association between osteoarthritis and femoroacetabular impingement is believed to exist, a long-term epidemiological study is needed to determine the natural history of these anatomical abnormalities.

Because the femoral head/neck junction is preserved in hip resurfacing, patients may be at greater risk of impingement, leading to abnormal wear patterns and pain. We assessed femoral head/neck offset in 63 hips undergoing metal-on-metal hip resurfacing and in 56 hips presenting with non-arthritic pain secondary to femoroacetabular impingement. Most hips undergoing resurfacing (57%; 36) had an offset ratio ≤ 0.15 pre-operatively and required greater correction of offset at operation than the rest of the group. In the non-arthritic hips the mean offset ratio was 0.137 (0.04 to 0.23), with the offset ratio correlating negatively to an increasing α angle. An offset ratio ≤ 0.15 had a 9.5-fold increased relative risk of having an α angle ≥ 50.5°. Most hips undergoing resurfacing have an abnormal femoral head/neck offset, which is best assessed in the sagittal plane.

Recently, femoroacetabular impingement has been recognised as a cause of early osteoarthritis. There are two mechanisms of impingement: 1) cam impingement caused by a non-spherical head and 2) pincer impingement caused by excessive acetabular cover. We hypothesised that both mechanisms result in different patterns of articular damage. Of 302 analysed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused damage to the anterosuperior acetabular cartilage with separation between the labrum and cartilage. During flexion, the cartilage was sheared off the bone by the non-spherical femoral head while the labrum remained untouched. In pincer impingement, the cartilage damage was located circumferentially and included only a narrow strip. During movement the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification.

Both cam and pincer impingement lead to osteoarthritis of the hip. Labral damage indicates ongoing impingement and rarely occurs alone.

Primary giant-cell tumour of soft tissue arising in the ligamentum teres has not been previously described. We report a case of such a tumour in a 46-year-old woman. The lesion was only detected at the time of hip arthroscopy despite pre-operative MRI being performed. It was successfully excised arthroscopically with resolution of the symptoms.

The radiological evaluation of the anterolateral femoral head is an essential tool for the assessment of the cam type of femoroacetabular impingement. CT, MRI and frog lateral plain radiographs have all been suggested as imaging options for this type of lesion. The alpha angle is accepted as a reliable indicator of the cam type of impingement and may also be used as an assessment for the successful operative correction of the cam lesion.

We studied the alpha angles of 32 consecutive patients with femoroacetabular impingement. The angle measured on frog lateral radiographs using templating tools was compared with that measured on CT scans in order to assess the reliability of the frog lateral view in analysing the alpha angle in cam impingement.

A high interobserver reliability was noted for the assessment of the alpha angle on the frog lateral view with an intraclass correlation coefficient of 0.83. The mean alpha angle measured on the frog lateral view was 58.71° (32° to 83.3°) and that by CT was 65.11° (30° to 102°). A poor intraclass correlation coefficient (0.08) was noted between the measurements using the two systems.

The frog lateral plain radiograph is not reliable for measuring the alpha angle. Various factors may be responsible for this such as the projection of the radiograph, the positioning of the patient and the quality of the image. CT may be necessary for accurate measurement of the alpha angle.

We undertook a prospective pilot study to determine whether arthroscopic surgery through the central compartment of the hip was effective in the management of a snapping iliopsoas tendon. Seven patients were assessed pre-operatively and at three, six, 12 and 24 months after operation. This included the assessment of pain on a visual analogue scale (VAS) and function using the modified Harris hip score.

All the patients had resolution of snapping post-operatively and this persisted at follow-up at two years. The mean VAS score for pain fell from 7.7 (6 to 10) pre-operatively to 4.3 (0 to 10) by three months (p = 0.051), and to 3.6 (1 to 8) (p = 0.015), 2.4 (0 to 8) (p = 0.011) and 2.4 (0 to 8) (p = 0.011) by six, 12 and 24 months, respectively. The mean modified Harris hip score increased from 56.1 (13.2 to 84.7) pre-operatively to 88.4 (57.2 to 100) at one year (p = 0.018) and to 87.9 (49.5 to 100) at two years (p = 0.02). There were no complications and no weakness occurred in the musculature around the hip.

Our findings suggest that this treatment is effective and would support the undertaking of a larger study comparing this procedure with other methods of treatment.

Objectives

Excessive acetabular coverage is the most common cause of pincer-type femoroacetabular impingement. To date, an association between acetabular over-coverage and genetic variations has not been studied. In this study we investigated the association between single nucleotide polymorphisms (SNPs) of paralogous Homeobox (HOX)9 genes and acetabular coverage in Japanese individuals to identify a possible genetic variation associated with acetabular over-coverage.

The August 2014 Shoulder & Elbow Roundup³⁶⁰ looks at: Myofibroblasts perhaps not implicated in post-traumatic elbow stiffness; olecranon tip biomechanically sound for coranoid reconstruction; obesity and elbow replacement don’t mix; single column plating successful for extra-articular distal humeral fractures; satisfaction not predictable in frozen shoulder; tenodesis and repair both acceptable in Grade II SLAP tears; glenoid bone grafting is effective and glenohumeral articular lesions best seen with an arthroscope.

The cam-type deformity in femoroacetabular impingement is a 3D deformity. Single measurements using radiographs, CT or MRI may not provide a true estimate of the magnitude of the deformity. We performed an analysis of the size and location of measurements of the alpha angle (α°) using a CT technique which could be applied to the 3D reconstructions of the hip. Analysis was undertaken in 42 patients (57 hips; 24 men and 18 women; mean age 38 years (16 to 58)) who had symptoms of femoroacetabular impingement related to a cam-type abnormality. An α° of > 50° was considered a significant indicator of cam-type impingement. Measurements of the α° were made at different points around the femoral head/neck junction at intervals of 30°: starting at the nine o’clock (posterior), ten, eleven and twelve o’clock (superior), one, two and ending at three o’clock (anterior) position.

The mean maximum increased α° was 64.6° (50.8° to 86°). The two o’clock position was the most common point to find an increased α° (53 hips; 93%), followed by one o’clock (48 hips; 84%). The largest α° for each hip was found most frequently at the two o’clock position (46%), followed by the one o’clock position (39%). Generally, raised α angles extend over three segments of the clock face.

Single measurements of the α°, whether pre- or post-operative, should be viewed with caution as they may not be representative of the true size of the deformity and not define whether adequate correction has been achieved following surgery.

Cite this article: Bone Joint J 2014;96-B:1167–71.

Aims

Femoroacetabular Junction Impingement (FAI) describes abnormalities in the shape of the femoral head–neck junction, or abnormalities in the orientation of the acetabulum. In the short term, FAI can give rise to pain and disability, and in the long-term it significantly increases the risk of developing osteoarthritis. The Femoroacetabular Impingement Trial (FAIT) aims to determine whether operative or non-operative intervention is more effective at improving symptoms and preventing the development and progression of osteoarthritis.

Over recent years hip arthroscopic surgery has evolved into one of the most rapidly expanding fields in orthopaedic surgery. Complications are largely transient and incidences between 0.5% and 6.4% have been reported. However, major complications can and do occur. This article analyses the reported complications and makes recommendations based on the literature review and personal experience on how to minimise them.

We report the clinical and radiological outcome of subcapital osteotomy of the femoral neck in the management of symptomatic femoroacetabular impingement (FAI) resulting from a healed slipped capital femoral epiphysis (SCFE). We believe this is only the second such study in the literature.

We studied eight patients (eight hips) with symptomatic FAI after a moderate to severe healed SCFE. There were six male and two female patients, with a mean age of 17.8 years (13 to 29).

All patients underwent a subcapital intracapsular osteotomy of the femoral neck after surgical hip dislocation and creation of an extended retinacular soft-tissue flap. The mean follow-up was 41 months (20 to 84). Clinical assessment included measurement of range of movement, Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis score (WOMAC). Radiological assessment included pre- and post-operative calculation of the anterior slip angle (ASA) and lateral slip angle (LSA), the anterior offset angle (AOA) and centre head–trochanteric distance (CTD). The mean HHS at final follow-up was 92.5 (85 to 100), and the mean WOMAC scores for pain, stiffness and function were 1.3 (0 to 4), 1.4 (0 to 6) and 3.6 (0 to 19) respectively. There was a statistically significant improvement in all the radiological measurements post-operatively. The mean ASA improved from 36.6° (29° to 44°) to 10.3° (5° to 17°) (p <  0.01). The mean LSA improved from 36.6° (31° to 43°) to 15.4° (8° to 21°) (p < 0.01). The mean AOA decreased from 64.4° (50° to 78°) 32.0° (25° to 39°) post-operatively (p < 0.01). The mean CTD improved from -8.2 mm (-13.8 to +3.1) to +2.8 mm (-7.6 to +11.0) (p < 0.01). Two patients underwent further surgery for nonunion. No patient suffered avascular necrosis of the femoral head.

Subcapital osteotomy for patients with a healed SCFE is more challenging than subcapital re-orientation in those with an acute or sub-acute SCFE and an open physis. An effective correction of the deformity, however, can be achieved with relief of symptoms related to impingement.

Cite this article: Bone Joint J 2014;96-B:1441–8.

Excessive acetabular cover secondary to a retroverted acetabulum causes pincer impingement, which may cause early osteoarthritis of the hip. Our aim was to determine if there was a relationship between acetabular version and osteoarthritis of the hip. Using image processing and analysis software we studied 117 CT images of the hip in patients aged less than 65 years who had undergone a CT virtual colonoscopy. The mean CT joint space of the 18 hips with acetabular retroversion was narrower compared with the 99 hips with normal acetabular alignment (p < 0.0001). A correlation of r = 0.46 (p < 0.01) was found between right hip acetabular version and the mean right hip joint space and of r = 0.31 (p = 0.02) between left hip acetabular version and the mean left hip joint space. Acetabular retroversion is associated with radiological evidence of osteoarthritis of the hip. An understanding of the mechanical basis of osteoarthritis of the hip allows early treatment of the underlying structural abnormality and prevents progression of the degenerative condition.

In Japan, osteoarthritis (OA) of the hip secondary to acetabular dysplasia is very common, and there are few data concerning the pathogeneses and incidence of femoroacetabular impingement (FAI). We have attempted to clarify the radiological prevalence of painful FAI in a cohort of Japanese patients and to investigate the radiological findings. We identified 176 symptomatic patients (202 hips) with Tönnis grade 0 or 1 osteoarthritis, whom we prospectively studied between August 2011 and July 2012. There were 61 men (65 hips) and 115 women (137 hips) with a mean age of 51.8 years (11 to 83). Radiological analyses included the α-angle, centre–edge angle, cross-over sign, pistol grip deformity and femoral head neck ratio. Of the 202 hips, 79 (39.1%) had acetabular dysplasia, while 80 hips (39.6%) had no known aetiology. We found evidence of FAI in 60 hips (29.7%). Radiological FAI findings associated with cam deformity were the most common. There was a significant relationship between the pistol grip deformity and both the α-angle (p < 0.001) and femoral head–neck ratio (p = 0.024). Radiological evidence of symptomatic FAI was not uncommon in these Japanese patients.

Cite this article: Bone Joint J 2013;96-B:172–6.