Background. Femoroacetabular impingement due to a reduced femoral head-neck-offset or excessive acetabular coverage will lead to early cartilage lesions of the hip joint. The purpose of the present study was to analyze the relationship between the extent of bony deformity and the presence and extent of cartilage lesions in femoroacetabular impingement. Methods. On the radiographs of 92 hip joints in 86 patients with a mean age of 36.5 ± 9.2 years who were operated on for with femoroacetabular impingement by surgical hip dislocation, the acetabular index of the weight-bearing zone, the center-edge-angle, the inclination of the acetabulum, the lateral-head-extrusion-index, retroversion signs of the acetabulum, the neck-shaft-angle, asphericity, superior and anterior alpha angles, and superior and anterior offset and offset ratios were assessed and correlated to the presence and extent of chondromalazia. Results. Acetabular chondromalazia was found in 60 hip joints. Full-thickness delamination of the acetabular cartilage was present in 42 of these hips with an average size of 1.1 ± 0.5 cm2. Femoral-sided chondromalazia was found in 9 hip joints. Hip joints with chondromalazia had a lower center-edge-angle (p = 0.014) and anterior offset ratio (p = 0.028) and a higher lateral-head-extrusion-index (p = 0.029). Hip joints with acetabular cartilage delamination had a significantly lower center-edge-angle (p = 0.012) and anterior offset (p = 0.03) and a significantly higher lateral-head-extrusion-index (p = 0.001) and superior (p = 0.006) and anterior alpha angles (p = 0.003). Conclusions. Marked cam-type femoral deformity and lesser coverage of the femoral head are associated with the acetabular cartilage lesions, arousing suspicion to the assumption that a large lateral aperture of the acetabulum abets proximal femora with cam-type deformity to inflict cartilage damage in femoroacetabular impingement

Femoroacetabular impingement (FAI) is a pathologic condition of the hip that leads to osteoarthrosis. The goal of the surgical hip dislocation is to correct the bony malformations to prevent the progression of osteoarthrosis. We investigated the topographical cartilage thickness variation in patients with FAI and early stage osteoarthrosis using an ultrasonic probe during surgical hip dislocation. We performed a prospective case-series of 38 patients (41 hips) that underwent surgical hip dislocation. The mean age at operation was 30.6 (range, 18–48) years. Indication for surgery was symptomatic FAI with 4 hips (10%) with pincer-type, 7 hips (17%) with cam-type, and 20 hips (73%) with mixed-type of FAI. Cartilage thickness was measured intraoperatively using an A-mode 22 MHz ultrasonic probe at 8 locations on the acetabular cartilage. The thickest acetabular cartilage was found in the weight bearing zone (range 2.8–3.5mm), whereas the thinnest cartilage was in the posterior acetabular horn (1.0–2.2 mm). In all hips, cartilage was thicker in the periphery area compared to the central area. In the anterior and posterior acetabular horn, the anterior area, and the superior area (central parts) a significantly decreased cartilage thickness in pincer-type compared to cam-type of FAI was found (p<0.05). Cartilage thickness shows topographical differences in all types of FAI with pincer-type of FAI having generally thinner cartilage than cam-type FAI. This is the first study measuring in vivo cartilage thickness in the human hip

Introduction. The MITCH PCR is an anatomic, flexible, horse-shoe shaped acetabular component, with 2 polar fins. The rationale of the PCR cup design is to reproduce a near-physiological stress distribution in the bone adjacent to the prosthesis. The thin composite cup is designed to fuse and flex in harmony with the surrounding bony structure. Only the pathological acetabular cartilage and underlying subchondral bone of the horseshoe-shaped, load-bearing portion of the acetabular socket is replaced, thus preserving viable bone stock. The PCR is manufactured from injection moulded carbon fibre reinforced polyetheretherketone (PEEK), with a two layer outer surface comprising hydroxyapatite and plasma sprayed commercially pure titanium. It is implanted in conjunction with a large diameter low wear femoral head, producing a bearing that will generate minimal wear debris with relatively inert particles. Pre-clinical mechanical testing, finite element analysis and biocompatibility studies have been undertaken. FEA evaluation predicts preservation of host bone density in the load bearing segments. A pilot clinical study was completed on a proto-type version of the PCR cup (the “Cambridge” cup), achieving excellent 5 and 10 year results. Subjects and Methods. We report the three-year results from a two-centre, prospective clinical evaluation study of the MITCH PCR cup. Patient outcome has been assessed using standardised clinical and radiological examinations and validated questionnaires. The change in physical level of activity and quality of life has been assessed using the Oxford Hip Score, Harris Hip score and the EuroQol-5D score, at scheduled time-points. Serial radiographs have been analysed to monitor the fixation and stability of the components. Results and Conclusions. In total 25 PCR cups were implanted by 3 surgeons. There were 12 men and 13 women. The mean patient age at time of surgery was 67 years (range 57–74). An Accolade TMZF stem was used as the femoral component in 19 patients and an Exeter stem in 6. The mean Oxford Hip score improved from 19.8 pre-operatively to 45 at the latest follow-up. The mean Euroqol-5D score improved from 62.6 to 83.6 and the Harris Hip score improved from 49.9 to 90.6. Three adverse events were noted in 2 patients (2 chest infections and 1 deep vein thrombosis). One revision of the acetabular component was performed at 21 months for squeaking. This has been investigated and modification of the articular geometry has resolved the problem on in-vitro testing

Introduction. Ectopic ossification (EO) at the acetabular rim has been suggested to be associated with pincer impingement and to lead to ossification of the labrum. However, this has never been substantiated with histological, radiographic and MRI findings in large cohorts of patients. We hypothesized that it is more a bone apposition of the acetabular rim and that it occurs more frequently in coxa profunda (CP) hips. Materials and Methods. In the first part, a cohort of 20 hips with this suspected ectopic rim ossification (EO) pattern were identified. The radiographic features that could be associated with this ossification pattern were described and evaluated by a histologic examination of intra-operative samples taken from the rim trimming. In the second part, we assessed the prevalence of this ectopic ossification process in a cohort of 203 patients treated for FAI. Results. Histologic examination revealed that new acetabular bone formation was either overgrowing the non-ossified labrum or moving it away from the native rim. Radiologically, this was associated with an “indentation sign” and/or a “double line sign”. There were no specimens that had shown any evidence of labral ossification. EO was found in 26 hips (18%) of the second cohort. Twenty of 26 hips (77%) with EO had CP morphology and 29% of CP hips had EO signs. In contrast, only 6 non-profunda hips (8%) were associated with EO. There was a high correlation between XR and MRI findings as >80% of XR findings were confirmed on MRI. Sixty-nine hips had CP morphology. The double line sign (N = 13), the indentation sign (N = 12) and a prominent lateral rim (N = 11) were found. Hips with an EO pattern were found in patients that were significantly older than those without EO (p = 0.01). The acetabular characteristics of the EO groups were not significantly different from the CP hips without EO. The femoral characteristics were significantly different between groups with lower neck shaft angles (128° vs 134°;p = 0,0002) and shorter femoral necks lengths (62mm vs 65mm; p = 0,04)) in the EO group. The mean Tonnis classification was not significantly different (p = 0,18). In addition, the mean acetabular cartilage degeneration status was not different between both groups (p = 0,9). Rim trimming down to the native acetabular bone was done in all cases either by arthroscopy (N = 40) or open surgical dislocation (N = 17). Discussion. Ectopic ossification of the acetabular rim predominantly occurs in CP and is associated with specific anatomic features of the proximal femur. This type of impingement seems to be different and less aggressive than other described impingement processes. The double line sign and indentation sign are highly indicative for this EO process and are indicative for a longstanding impingement problem. Trimming of the acetabular rim should be conducted

Aims

The aims of this study were to determine the cumulative ten-year survivorship of hips treated for acetabular fractures using surgical hip dislocation and to identify factors predictive of an unfavourable outcome.

Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9).

Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports.

Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis.

The aim of this study was to analyse the functional outcome after a displaced intracapsular fracture of the femoral neck in active patients aged over 70 years without osteoarthritis or rheumatoid arthritis of the hip, randomised to receive either a hemiarthroplasty or a total hip replacement (THR). We studied 252 patients of whom 47 (19%) were men, with a mean age of 81.1 years (70.2 to 95.6). They were randomly allocated to be treated with either a cemented hemiarthroplasty (137 patients) or cemented THR (115 patients). At one- and five-year follow-up no differences were observed in the modified Harris hip score, revision rate of the prosthesis, local and general complications, or mortality. The intra-operative blood loss was lower in the hemiarthroplasty group (7% > 500 ml) than in the THR group (26% > 500 ml) and the duration of surgery was longer in the THR group (28% > 1.5 hours versus 12% > 1.5 hours). There were no dislocations of any bipolar hemiarthroplasty and eight dislocations of a THR during follow-up.

Because of a higher intra-operative blood loss (p < 0.001), an increased duration of the operation (p < 0.001) and a higher number of early and late dislocations (p = 0.002), we do not recommend THR as the treatment of choice in patients aged ≥ 70 years with a fracture of the femoral neck in the absence of advanced radiological osteoarthritis or rheumatoid arthritis of the hip.