Thru purpose of this study was to evaluate the clinical outcomes of a consecutive series of conversion total hip arthroplasty (cTHA) following previous hip fractures.

A retrospective chart review of patients who underwent cTHAs from 2008–2017 at an urban academic teaching institution was performed.

Eighty-eight patients were included in this study. The mean age at the cTHA was 66 years (range 27 to 89). 67% of the patients wre women. The mean BMI was 28 kg/m² (range 17 to 41). The mean Charlson Comorbidity Index was 3 (range 0 to 9). The mean follow-up was 49 months (range 24 to 131). The mean duration from the hip fracture fixation to the cTHA was 51 months (range 10 to 144). The mean operating time was 188 minutes, (range 71 to 423) with a mean estimated blood loss of 780 ml (range 300 to 2500). Revision-type (long-stem) designs were used in 65% of the cases. The mean length of hospital stay was 8 days (range 2 to 61). The readmission rate was 37% within 90 days after the CTHAs. Of these, 57% were due to non-orthopaedic complications. There were 10 orthopaedic complications: 7 PJIs, all of which required I&D and 3 required staged revision. There were 2 dislocations treated with closed reduction and 1 case of intraoperative periprosthetic femur fracture during femoral component insertion. There was no revision for aseptic loosening within the follow-up period. The one-year mortality rate was 0%.

cTHAs were associated with longer operating time, more blood loss, longer length of hospital stay, and higher readmission rates than the primary THAs in our institutional database. We believe utilizing a multi-disciplinary care protocol to optimize these patients is needed to reduce the high rate of readmissions, and the complications in this patient population.

Modular tapered stems have become increasingly popular in femoral revisions and stem subsidence remains a reported clinical problem. Computer modeling and biomechanical testing demonstrated a minimum initial line-to-line fit of 25 mm was required to reduce the risk of subsidence. We examined XR imaging of 110 consecutive femoral revisions by a single surgeon using two different modular tapered stems to determine if this biomechanical threshold was of clinical relevance. 72% of the revisions were done for aseptic loosening and 28% for periprosthetic fracture or infection. Stem subsidence of any degree was observed in 24 (21.8%), while 12 (10.9%) demonstrated substantial subsidence of > 10 mm. We matched this cohort to 12 patients who had no stem subsidence. The average age of patients with subsidence was 59 years (43 to 79 years). The average of patients without subsidence was 66 years (41 to 77 years). Each group had 7 men and 5 women. Stem subsidence was observed in the first 3 months post-surgery. The demographics, bone deficiency, stem design, and stem diameter were similar between groups.

83% of patients with substantial stem subsidence had less than 25 mm of line-to-line fit compared to 17% of patients without subsidence. The 12 cases of no stem subsidence had a mean line-to-line fit of 48 mm (25 to 55 mm). 75% of patients with substantial stem subsidence had also undergone an extended trochanteric osteotomy (ETO) compared to 33% of patients without subsidence.

We conclude that there is a positive correlation with the biomechanical testing parameters and substantial stem subsidence. ETO was found to be associated with higher stem subsidence.

The purpose of this study was to review the clinical and radiographic outcome in THRs done following acetabular fractures (fx). All patients undergoing conversion THR after previous acetabular fx between 1990 and 2006 at a single institution were identified.

Clinical evaluation was done using the Harris hip scale. Radiographic evaluation was done using the system proposed by the Hip society. THRs as part of initial treatment for acute acetabular fx were excluded.

There were 90 THRs (90 patients) performed in patients previously treated for an acetabular fracture. At the time of their acetabular facture, 67 had been treated with ORIF, 12 were treated with closed or limited open reduction and percutaneous fixation, and 11 were treated without surgery. The mean age at injury was 43.7 years, (range, 14–79). 68 patients sustained their fx from a high-energy mechanism (MVC, MPC, or MCC).

Three patterns accounted for 52% of the fx: transverse posterior wall (20), both column (18), and T-Type (9). Associated pelvic fractures were present in 14 patients. Associated ipsilateral proximal femur fractures were present: femoral head (four), femoral neck (five), and femoral shaft (three). Among those treated with ORIF, marginal impaction was noted in 31 and osteo-chondral head damage in 32 hips.

The mean interval between injury and THR was 42 months (range, two months to 32 years). Cement-less fixation was used in 81 of the 90 cups. Similarly, cementless stems were used in 80 stems. Bone graft was necessary in 26 patients (17 autograft, nine allograft). Two cases each required pelvic augments and reinforcement cage, respectively.

Additional findings at THR included: femoral head erosion (53 hips), femoral head osteonecrosis (37 hips), osteonecrosis of the acetabulum (22 hips), and fx non-union (six hips). The average cup abduction angle was 440 (range, 28 to 60), the average cup height was 24 mm (range, 10 to 42), and the average medialization distance was 23 mm (range, 5 to 48). The mean EBL was 810 ml and mean operative time was 195 minutes. The mean F/U was 36 months (range, 6 months to 17 years). The median Harris hip score was 89 at the most recent F/U. Fifteen revisions (16%) have been done: aseptic loosening (seven hips), recurrent dislocation (six hips) and infection (two hips).

Five of the six revisions for recurrent dislocation were performed in patients who had a posterior approach for both their acetabular fracture treatment and their THR. No revision was done in those who had been initially with percutaneous fixation. There was no infection in those who had been initially with percutaneous fixation either from the fx treatment or the THR. In contrast, 14 ORIF patients were complicated by infection. One of these developed infection following THR.

Our data support the clinical efficacy and mid-term durability of THR in this patient group. Aseptic loosening and recurrent dislocation remain the primary reasons for revision surgery.

We report a prospective study of the liner-metal interfaces of modular uncemented acetabular components as sources of debris. We collected the pseudomembrane from the screw-cup junction and the empty screw holes of the metal backing of 19 acetabula after an average implantation of 22 months. Associated osteolytic lesions were separately collected in two cases. The back surfaces of the liners and the screws were examined for damage, and some liners were scanned by electron microscopy. The tissues were studied histologically and by atomic absorption spectrophotometry to measure titanium content. The pseudomembrane from the screw-cup junction contained polyethylene debris in seven specimens and metal debris in ten. The material from empty screw holes was necrotic tissue or dense fibroconnective tissue with a proliferative histiocytic infiltrate and foreign-body giant-cell reaction. It contained polyethylene debris in 14 cases and metal in five. The two acetabular osteolytic lesions also showed a foreign-body giant-cell reaction to particulate debris. The average titanium levels in pseudomembranes from the screw-cup junction and the empty screw holes were 959 micrograms/g (48 to 11,900) and 74 micrograms/g (0.72 to 331) respectively. The tissue from the two lytic lesions showed average titanium levels of 139 and 147 micrograms/g respectively. The back surfaces of the PE liners showed surface deformation, burnishing, and embedded metal debris. All 30 retrieved screws demonstrated fretting at the base of the head and on the proximal shaft. Non-articular modular junctions create new interfaces for the generation of particulate debris, which may cause granulomatous reaction.

We reviewed the plain radiographs, bone scans and hip aspiration results of 54 patients with painful hip arthroplasties which had been explored surgically, to compare the results of the investigations with the operative findings. For acetabular loosening, the sensitivity and specificity of bone scanning were 87% and 95%, with an accuracy of 90%: for serial plain radiography sensitivity was 95%, specificity 100% and accuracy 97%. For femoral component loosening, bone scan sensitivity was 85%, specificity 100% and accuracy 89%: the sensitivity of plain radiography was 100%, with specificity 92% and accuracy 98%. Technetium bone scanning did not provide additional information with regard to loosening and is not necessary in the routine investigation of a painful hip arthroplasty. Serial pain radiography is the most effective method of detecting loosening, and bone scanning is useful only when radiography is inconclusive with regard to loosening or infection.