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: EMG recording from lumber spine muscles can be a reliable discriminator and predictor of low back pain (LBP). Multi variant analysis shows age influences these variables.

Aim: to determine in a longitudinal study if age is a significant factor.

Method: EMG recording from 9 subjects was carried out at time1 and 12 years afterwards (time 2);

at the same load and

Results: At the same load there was no significant change in the Mean Half Width (HW) from time1 (M=45.9, SD=19.1) to time 2 (M=51.4, SD=18.7), t(8)= −0.98, p=0.36. No difference was observed when the load set at time 1 was used at time 2 (M=51.4, SD=18.7) and compared with a load set from the MVC obtained at time 2 (M=45.9, SD=12.0), t(8)=1.75, p=0.118.. There was no statistically significant difference between Initial Median Frequency (IMF) at time1 (M=50.6, SD=12.0) and time 2, either using the same load (M=51.7, SD=8.6), t(8)=− 0.273, p=0.79) or the load based on current MVC.

Discussion: In this 12 year longitudinal study, age did not appear to affect the HW or IMF measurement. Both of these variables might be used in long term studies.

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.

Introduction: Revision total hip replacement has high rates of failure which appears to be due, in part, to deficient bone stock that does not provide an adequate environment for fixation of the implant. Cementless modular implant offers the possibility of restoration of bone stock in conjunction with adequate fixation, thus re-establishing the function of the hip without the use of additional cement. This study reviews patients treated with the S-ROM system, assessing clinical outcomes, implant stability and osseous response to the hip revisions.

Methods: Sixty two cementless revision hip arthroplasties were performed using the S-ROM prosthesis between 1996 and 2001. Fifty four were available for follow up evaluation at 3 to 8 years (median 4.5 years). Radiological analysis, patient satisfaction and Harris hip scores were assessed pre and post operatively then at average of 4.5 years later.

Results: Eighty-five percent of patients were satisfied with the result of surgery. Clinical scores improved from a preoperative value 34 to 80 points post-operatively and were maintained on further assessment at average of 4.5 years. Forty-three stems had solid bony ingrowth, nine had mild subsidence initially averaged 6.4 mm then stabilized. Two had marked initial subsidence, which also later stabilised. There was gradual filling of the osteolytic defects in 32 of the 37 (86.5%) femoral lesions.

Discussion: With improvement of the postoperative hip score by more than 50 points and absence of definite implant instability at the final follow up, the results of use of S-ROM prosthesis in the revision cases of this study seems to be successful. The follow up is relatively short, but the experience derived from this work confirms the versatility of the S-ROM prosthesis in the complex hip revision situations as well as its favourable mechanical and biologic impact on the adjacent osseous structures.

To assess the performance of calcium sulphate pellets as a bone graft substitute in an Orthopaedic Oncology practice using clinical and radiological outcomes.

Between 1998 and 2001, calcium sulphate pellets were used in cavitary defects in 38 procedures in 34 patients with bone tumours. In 29 calcium sulphate pellets were used alone, in 8 allograft and in 1 autograft bone was added. The diagnosis was unicameral bone cyst in 13, giant cell tumour in 11, non-ossifying fibroma in 2, chondroblastoma in 2, benign fibrous histiocytoma in 2 and another pathology in 8 procedures. The femur was involved in 12 procedures, the humerus in 8, the radius in 5, the tibia in 4, the fibula in 3, the calcaneus in 2, and one procedure each in the tarsal cuboid, a metatarsal, the talus, and the middle phalanx of a finger.

Median follow up was 14 months (3 to 48). Seven patients had wound complications. Pellets had absorbed completely in 26/28 (93%) evaluable procedures by 3 months. Healing of the defect occurred in 24/28 (86%) evaluable procedures by 6 months. In 6 cases, the healed defect contained cystic areas simulating local recurrence. In 3 cases, there was collapse of the defect.

In cavitary defects, calcium sulphate pellets reliably absorb. Some patients have wound complications, especially where the cavity is relatively superficial. The pellets do not provide mechanical stability where there is attenuated cortical bone. Cysts within the healed defect may simulate recurrence.