Aims

This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

Objectives. The number of surgical procedures performed each year to treat femoroacetabular impingement (FAI) continues to rise. Although there is evidence that surgery can improve symptoms in the short-term, there is no evidence that it slows the development of osteoarthritis (OA). We performed a feasibility study to determine whether patient and surgeon opinion was permissive for a Randomised Controlled Trial (RCT) comparing operative with non-operative treatment for FAI. Methods. Surgeon opinion was obtained using validated questionnaires at a Specialist Hip Meeting (n = 61, 30 of whom stated that they routinely performed FAI surgery) and patient opinion was obtained from clinical patients with a new diagnosis of FAI (n = 31). Results. Clinical equipoise was demonstrated when surgeons were given clinical scenarios and asked whether they would manage a patient operatively or non-operatively. A total of 23 surgeons (77%) who routinely perform FAI surgery were willing to recruit patients into a RCT, and 28 patients (90%) were willing to participate. 75% of responding surgeons believed it was appropriate to randomise patients to non-operative treatment for ≥ 12 months. Conversely, only eight patients (26%) felt this was acceptable, although 29 (94%) were willing to continue non-operative treatment for six months. More patients were concerned about their risk of developing OA than their current symptoms, although most patients felt that the two were of equal importance. Conclusions. We conclude that a RCT comparing operative and non-operative management of FAI is feasible and should be considered a research priority. An important finding for orthopaedic surgical trials is that patients without life-threatening pathology appear willing to trial a treatment for six months without improvement in their symptoms

Aims

In the native hip, the hip capsular ligaments tighten at the limits of range of hip motion and may provide a passive stabilizing force to protect the hip against edge loading. In this study we quantified the stabilizing force vectors generated by capsular ligaments at extreme range of motion (ROM), and examined their ability to prevent edge loading.

We examined 524 patients with whiplash injuries for delayed onset of shoulder pain in order to establish whether this was due to impingement syndrome. A total of 476 patients (91%) responded to a questionnaire of which 102 (22%) were entered into the study; 43 had both a positive impingement sign and Neer test. The incidence of impingement-type pain was 9%. After treatment 23 patients (5%) had a significant improvement in their symptoms, ten (2%) had a moderate improvement and nine had no improvement. Impingement-type pain can occur after whiplash injuries and can be successfully treated

Conventional treatment of mild slipped capital femoral epiphysis consists of fixation in situ with wires or screws. Recent contributions to the literature suggest that even a mild slip may lead to early damage of the acetabular labrum and adjacent cartilage by abutment of a prominent femoral metaphysis. It has been suggested that the appropriate treatment in mild slipped capital femoral epiphysis should not only prevent further slipping of the epiphysis, but also address potential femoroacetabular impingement by restoring the anatomy of the proximal femur. Between October 1984 and December 1995 we treated 16 patients for unilateral mild slipped capital femoral epiphysis by fixation in situ with Kirschner wires. In this study we have reviewed these patients for clinical and radiological evidence of femoroacetabular impingement. There was little clinical indication of impingement but radiological evaluation assessing the femoral head-neck ratio and measuring the Nötzli α angle on the anteroposterior and cross-table radiographs showed significant alterations in the proximal femur. None of the affected hips had a normal head-neck ratio and the mean α angle was 86° (55° to 99°) and 55° (40° to 94°) on the anteroposterior and lateral cross-table radiographs, respectively. While our clinical data favours conventional treatment, our radiological findings are in support of restoring the anatomy of the proximal femur to avoid or delay the development of femoroacetabular impingement following mild slipped capital femoral epiphysis

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

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

Aims

Iliopsoas pathology is a relatively uncommon cause of pain following total hip arthroplasty (THA), typically presenting with symptoms of groin pain on active flexion and/or extension of the hip. A variety of conservative and surgical treatment options have been reported. In this retrospective cohort study, we report the incidence of iliopsoas pathology and treatment outcomes.

We report a retrospective study of 46 patients with continuing difficulties after anterior reconstruction of a shoulder for instability. In 31 patients instability was still present; in 12 of these, posterior or multidirectional instability had not been recognised and a further 11 had an uncorrected anatomical defect. In 20 patients with significant pain there was often more than one cause: impingement syndrome was seen in nine, osteoarthritis in seven, implant irritation in four and instability alone in two. A disabling medial rotation contracture was seen in 10 patients, four of whom had painful osteoarthritis. We conclude that recurrence of symptoms may imply that the direction of the instability was not recognised, that an anterior repair should not be too tight, and that pain after successful stabilisation is often due to impingement

The painful subluxed or dislocated hip in adults with cerebral palsy presents a challenging problem. Prosthetic dislocation and heterotopic ossification are particular concerns. We present the first reported series of 19 such patients (20 hips) treated with hip resurfacing and proximal femoral osteotomy. The pre-operative Gross Motor Function Classification System (GMFCS) was level V in 13 (68%) patients, level IV in three (16%), level III in one (5%) and level II in two (11%). The mean age at operation was 37 years (13 to 57). The mean follow-up was 8.0 years (2.7 to 11.6), and 16 of the 18 (89%) contactable patients or their carers felt that the surgery had been worthwhile. Pain was relieved in 16 of the 18 surviving hips (89%) at the last follow-up, and the GMFCS level had improved in seven (37%) patients. There were two (10%) early dislocations; three hips (15%) required revision of femoral fixation, and two hips (10%) required revision, for late traumatic fracture of the femoral neck and extra-articular impingement, respectively. Hence there were significant surgical complications in a total of seven hips (35%). No hips required revision for instability, and there were no cases of heterotopic ossification. We recommend hip resurfacing with proximal femoral osteotomy for the treatment of the painful subluxed or dislocated hip in patients with cerebral palsy

In this prospective study a total of 80 consecutive Chinese patients with Crowe type I or II developmental dysplasia of the hip were randomly assigned for hip resurfacing arthroplasty (HRA) or total hip replacement (THR). Three patients assigned to HRA were converted to THR, and three HRA patients and two THR patients were lost to follow-up. This left a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips) who underwent THR. The mean follow-up was 59.4 months (52 to 70) in the HRA group and 60.6 months (50 to 72) in the THR group. There was no failure of the prosthesis in either group. Flexion of the hip was significantly better after HRA, but there was no difference in the mean post-operative Harris hip scores between the groups. The mean size of the acetabular component in the HRA group was significantly larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was no difference in the mean abduction angle of the acetabular component between the two groups. Although the patients in this series had risk factors for failure after HRA, such as low body weight, small femoral heads and dysplasia, the clinical results of resurfacing in those with Crowe type I or II hip dysplasia were satisfactory. Patients in the HRA group had a better range of movement, although neck-cup impingement was observed. However, more acetabular bone was sacrificed in HRA patients, and it is unclear whether this will have an adverse effect in the long term

Many designs of unicompartmental knee replacement show early and mid-term failure due to polyethylene wear. We studied the wear rate of congruent polyethylene meniscal bearings retrieved from failed Oxford unicompartmental knee replacements. We examined 16 bearings, 0.8 to 12.8 years after implantation, measuring their thickness and comparing it with that of 14 unused bearings. The mean rate of penetration, which included the effects of wear at both upper and lower surfaces, was 0.036 mm per year (maximum 0.08). Bearings as thin as 3.5 mm wore no faster than thicker models, but ten with evidence of impingement had greater wear. The six bearings with no impingement showed a mean rate of penetration of 0.01 mm per year. In unicompartmental knee replacement, careful implantation of fully congruous meniscal bearings can avoid failure due to polyethylene wear

We studied MR images of the spine in a consecutive series of 100 patients with acute compression of the spinal cord due to metastases. All patients had documented neurological deficit and histologically proven carcinoma. MRI was used to localise bony metastatic involvement and soft-tissue impingement of the cord. A systematic method of documenting metastatic involvement is described. A total of 43 patients had compression at multiple levels; 160 vertebral levels were studied. In 120 vertebrae (75%), anterior, lateral and posterior bony elements were involved. Soft-tissue impingement of the spinal cord often involved more than one quadrant of its circumference. In 69 vertebrae (43%) there was concomitant anterior and posterior compression. Isolated involvement of a vertebral body was observed in only six vertebrae (3.8%). We have shown that in most cases of acute compression of the spinal cord due to metastases there is coexisting involvement of both anterior and posterior structures

We investigated factors that were thought to be associated with an increased incidence of squeaking of ceramic-on-ceramic total hip replacements. Between June 1997 and December 2008 the three senior authors implanted 2406 primary total hip replacements with a ceramic-on-ceramic bearing surface. The mean follow-up was 10.6 years. The diagnosis was primary osteoarthritis in each case, and no patient had undergone previous surgery to the hip. We identified 74 squeaking hips (73 patients) giving an incidence of 3.1% at a mean follow-up of 9.5 years (4.1 to 13.3). Taller, heavier and younger patients were significantly more likely to have hips that squeaked. Squeaking hips had a significantly higher range of post-operative internal (p = 0.001) and external rotation (p = 0.003) compared with silent hips. Patients with squeaking hips had significantly higher activity levels (p = 0.009). A squeaking hip was not associated with a significant difference in patient satisfaction (p = 0.24) or Harris hip score (p = 0.34). Four implant position factors enabled good prediction of squeaking. These were high acetabular component inclination, high femoral offset, lateralisation of the hip centre and either high or low acetabular component anteversion. This is the largest study to date to examine patient factors and implant position factors that predispose to squeaking of a ceramic-on-ceramic hip. The results suggest that factors which increase the mechanical forces across the hip joint and factors which increase the risk of neck-to-rim impingement, and therefore edge-loading, are those that predispose to squeaking

Aims

Arthroplasty has become increasingly popular to treat end-stage ankle arthritis. Iatrogenic posterior neurovascular and tendinous injury have been described from saw cuts. However, it is hypothesized that posterior ankle structures could be damaged by inserting tibial guide pins too deeply and be a potential cause of residual hindfoot pain.

Age-related localised deposition of amyloid in connective tissue has been found in degenerative articular and periarticular tissue. Biopsies of the supraspinatus tendon of 28 patients undergoing repair of the rotator cuff were analysed histologically for the presence of localised deposition of amyloid. There was a long history of impingement in 20 patients, and eight patients had suffered an acute traumatic tear with no preceding symptoms. Localised deposition of amyloid identified by Congo Red staining was detected in 16 samples (57%). Amyloid was present in 14 (70%) of the degenerative tears, but in only two (25%) of the acute tears. Immunohistochemical staining showed that the amyloid deposits were positive for P component, but negative for κ and λ light chains, prealbumin, and β2 microglobulin. Critical electrolyte staining revealed highly-sulphated glycosaminoglycans at sites of deposition of amyloid. The presence of localised deposition of amyloid in tears of the rotator cuff is likely to represent irreversible structural changes. These findings support the theory that impingement and tears are due to intrinsic degenerative changes within the tendons of the rotator cuff