Background

Thrust plate prosthesis (TPP) is a bone conserving prosthesis in use for over thirty years. TPP is a stemless and uncemented femoral prosthesis fixed at the lateral femoral cortex with a bolt, plate and screw. This has a metal-on-metal articulation with a 28mm Metasul head and Allofit press fit acetabular cup. Our study aimed to assess the functional outcome of this prosthesis.

Thrust plate prosthesis (TPP) is a bone conserving prosthesis in use for over thirty years. TPP is a stemless and uncemented femoral prosthesis fixed at the lateral femoral cortex with a bolt, plate and screw. This has a metal-on-metal articulation with a 28mm Metasul head and Allofit press fit acetabular cup. Our study aimed to assess the survival of this prosthesis. At Oswestry 234 TTP's were implanted between 1995 and 2005. All patients completed a self-assessed questionnaire of Harris Hip Score pre-operatively and post-operatively at 2 months, 1 year, and then yearly. Only those who had a follow up was within the last two years were included in the analysis. 76 patients who had failed to satisfy the criteria were excluded. Of the 158 hips in the study 75 hips were in male patients and 83 were in female patients. The median age of patients was 52 years (range 15 to 82). 75 hips were on the right side and 83 on the left. All patients were operated by the senior author or a senior trainee under his supervision (seven hips). Revision of the implant or decision to revise was taken as the end point of our study. The median time to follow up was 7 years (range 1 to 15). The median pre-operative hip score was 43 (range 3 to 77) which rose to 83 points (range 11 to 100) at the latest follow up. Median hip score in females improved from 39 to 82 points and in males from 52 to 85 points. Twelve patients (5.1%) underwent revision surgery either for infection or aseptic loosening. The Thrust Plate Prosthesis had a good outcome with an increase in hip score of 40 points and 94.9 % survival at a median of 7 years.

Introduction: Experimental studies in anatomic full size hip models indicate that larger femoral heads offer potential in providing greater hip range of motion and joint stability. We studied the effects of increasing head diameter from 28mm to 36 mm in total hip replacement (THR) on the range of flexion and abduction.

Methods: 243 patients who underwent primary total hip replacement with S ROM prosthesis between July 1996 and June 2004 were studied. 151 patients (77 male and 74 female) underwent THR with 28 mm head and 92 patients (38 male and 54 female) underwent THR with 36 mm head. The range of flexion and abduction were studied and statistical analysis was performed using the Student t-test. We monitored the dislocation rate in both groups.

Results: The mean flexion is 87.0 for the 28 mm group and 89.6 for the 36 mm group. The mean abduction is 27.77 and 27.98 for 28mm and 36mm groups respectively. Even though there is a slight increase in the mean flexion and abduction from the 28mm to 36mm group, this increase in not found to be statistically significant. For flexion (2.6 (−0.85 to 3.2); p=0.377), and for abduction (0.02 (−2.37 to 1.94); p=0.847). Three hips dislocated in the 28mm group (2%) but none of the hips in 36mm group has dislocated.

Discussion: Even though experimental studies indicate improvement in range of motion with increasing head diameter in THR, this effect is not reflected in our clinical study. But there is improvement in the joint stability by using a prosthesis with larger head diameter as evidenced by a reduction in the dislocation rate.

Study Design: Prospective analysis of a cohort of patients who underwent a Spinal Fitness Exercise Program in a nurse led spinal assessment clinic in a University Hospital.

Objective: To determine if psychological status affects the outcome of a spinal fitness exercise program in patients with low back pain.

Background: Evidence for the effectiveness of exercise programs in the treatment of chronic mechanical low back pain is well documented. In this study, the effect of psychological status on the outcome of a self-help spinal fitness exercise programme was studied.

Methods: Patients who were referred by their primary care physicians to the nurse led spinal assessment clinic and met the inclusion criteria were given a spinal exercise booklet, which describes with the aid of diagrams how to perform a series of lumbar core stability exercises for them to practise at home. Back pain related disability was assessed before and 3 months after the exercise program using the Oswestry Disability Index (ODI). Psychological status was measured using the Distress and Risk Assessment Method (DRAM). This classifies patients into 4 groups based on the combination of scores from the Modified Somatic Perception Questionnaire (MSPQ, 13 questions, scored 0–13) and Modified Zung Questionnaire (23 questions scored 0–69): normal, at risk, distressed somatic and distressed depressive.

Results: Forty one patients were enrolled into the study (19 male, 22 female, mean age at treatment 45.8 years, age range 22–78 years). The DRAM scores showed that 9 had no psychological disturbance (normal), 17 were at risk, 4 were distressed somatic and 11 distressed depressive. Even though there was a statistically significant improvement in the mean ODI after the exercise program for all DRAM groups, the improvement in the ODI was not significantly different between the four groups (ANOVA, p = 0.596).

Conclusions: Our study suggests that the outcome of a spinal fitness exercise programme is not affected by the psychological status of the patient. We conclude that patients should not be excluded from spinal fitness exercise programs on the basis of psychological status.

Introduction: Pain after total hip arthroplasty (THA) can be caused by infection, aseptic loosening, heterotopic ossification, and referred pain. Psoas tendonitis is a rare cause of groin pain after THA and resurfacing arthroplasty. It is believed to be caused by psoas tendon impingement against a malpositioned acetabular component due to defective anteversion or centring and the use of oversized cups. We report 4 cases of psoas tendonitis following resurfacing arthroplasty and hybrid surface arthroplasty.

Methods: Between April 2004 and June 2005, we diagnosed 4 cases (3 female and 1 male) of psoas tendonitis among 152 cases of resurfacing arthroplasty and hybrid surface arthroplasty (2.6%). 116 patients had a hip resurfacing with ASR prosthesis (2 cases, 1.7%) and 36 patients had hybrid surface arthroplasty with ASR unipolar head on S ROM stem (2 cases, 5.6%). All these patients presented 2–5 months postoperatively with severe groin pain which was exaggerated when moving from the sitting position to the upright position and when going up stairs. Common causes of pain after hip arthroplasty, infection and loosening were ruled out. Radiological and ultrasound examination were performed.

Results: Ultrasound examination revealed thickening of psoas tendon in all cases and fluid collection around the tendon in one case. All cases were treated with corticosteroid injection under ultrasound guidance. Significant but temporary symptomatic relief was achieved in all cases.

Discussion: Psoas tendonitis should be considered in the differential diagnosis of groin pain after hip resurfacing procedures. Ultrasound examination is the initial investigation of choice and corticosteroid injection around the tendon is initial method of treatment. Computerized tomography and surgical options of management should be considered in resistant cases.

Introduction: Design of the prosthesis is an important factor in the successful outcome and longevity of total hip replacement. The purpose of the present study is to evaluate the minimum six-year results of primary total hip replacement using LX cemented prosthesis.

Methods: We prospectively studied 177 patients (60 male and 117 female) who underwent 197 hip replacements, between 1996 and 1999, using LX cemented prosthesis comprising a femoral component with cylindrical cross section of the stem and an acetabular component of ultrahigh molecular weight polyethylene. The average follow up was 7.3 years (6.1–9.6years). Clinical (Harris Hip Score) and radiological assessments (Barrack’s grading of cementation, subsidence, debonding, radiolucent lines and osteolysis) were performed.

Results: The average Harris Hip Score is 85.53 (28–99) compared to the preoperative score of 59.28. 28 cases (14.2%) developed progressive radiolucent lines around the stem. Sinking and debonding of the stem was noted in 18 cases (9.1%). 15 hips (7.6%) have dislocated and 11 were recurrent dislocations. Revision hip replacement was carried out in 12 cases (6%) for subsidence and debonding of stem, cement fracture and recurrent dislocation. The femoral stem components were found to be loose at the time of surgery.

Discussion: We believe that design of the prosthesis is an important factor in the high incidence of subsidence and debonding of the femoral stem. Both the geometry (cylindrical shape) and the rough surface finish (Ra value 100 microinches) were responsible for the pattern of progressive loosening. Lack of progressive increase in the offset with increase in the size of femoral component from 1 to 2 is one of the factors which contributed to high incidence of dislocation.

Introduction: Experimental studies in anatomic full size hip models indicate that larger femoral heads offer potential in providing greater hip range of motion and joint stability. We studied the effects of increasing head diameter from 28mm to 36 mm in total hip replacement (THR) on the range of flexion and abduction.

Methods: 243 patients who underwent primary total hip replacement with S ROM prosthesis between July 1996 and June 2004 were studied. 151 patients (77 male and 74 female) underwent THR with 28 mm head and 92 patients (38 male and 54 female) underwent THR with 36 mm head. The range of flexion and abduction were studied and statistical analysis was performed using the Student t-test. We monitored the dislocation rate in both groups.

Results: The mean flexion is 87.0 for the 28 mm group and 89.6 for the 36 mm group. The mean abduction is 27.77 and 27.98 for 28mm and 36mm groups respectively. Even though there is a slight increase in the mean flexion and abduction from the 28mm to 36mm group, this increase in not found to be statistically significant. For flexion (2.6 (−0.85 to 3.2); p=0.377), and for abduction (0.02 (−2.37 to 1.94); p=0.847). Three hips dislocated in the 28mm group (2%) but none of the hips in 36mm group has dislocated.

Discussion: Even though experimental studies indicate improvement in range of motion with increasing head diameter in THR, this effect is not reflected in our clinical study. But there is improvement in the joint stability by using a prosthesis with larger head diameter as evidenced by a reduction in the dislocation rate.

Introduction: The distorted anatomy in Developmental Dysplasia of the Hip (DDH) makes a total hip arthroplasty (THA) a challenging procedure. The purpose of the current study is to report the midterm results after uncemented primary hip arthroplasty using S ROM prosthesis in a prospective series of patients with hip dysplasia.

Methods: We performed 22 uncemented total hip replacements using S ROM prosthesis in 21 (12 female and 9 male) patients with hip dysplasia. The means age at the time of hip surgery was 41.8 (22 to 64) years. The mean follow-up was 6.3 (3.8 to 9.6) years. In 9 (40.9%) patients the operative treatment of DDH was performed during the early childhood (femoral osteotomy in 6 and pelvic osteotomy in 3). All patients were evaluated clinically and radiologically. The femoral head displacement prior to THA surgery was classified according to Crowe at al. classification (4 hips were type1, 2 type2, 10 type3 and 6 type 4).

Results: The average Harris Hip Score improved from 29.48 to 72.76 (44 to 99) and the average Oxford hip score is 31.22 (12 to 47). The range of flexion is 60°–120° (average 83.23) and abduction is 10°–40°(average 22.94). None of the hips has dislocated. Radiolucent lines were noted around the femoral stem in one case. None of the cases have developed osteolysis around femoral prosthesis. In one patient (4.5%), revision hip surgery was done for aseptic loosening of cemented acetabular cup.

Discussion: The midterm results of total hip replacement in DDH using S ROM uncemented prosthesis are promising. We recommend this modular prosthesis for hip replacement in dysplastic hips.