الفهرس 
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Abstract
The number of total hip arthroplasties (THAs) and revision arthroplasties continues to increase year on year worldwide. Revision surgery often presents a spectrum of complex surgical challenges particularly when complicated with proximal bone loss. The primary goal of successful revision hip surgery is to achieve immediate implant stability and to achieve early rehabilitation and functional recovery and good long-term outcomes.
We conducted a prospective clinical study to evaluate the clinical and radiological outcomes of using uncemented taper-modular fluted titanium (TMFT) stems in revision hip surgeries.
The study was carried out in 55 patients (57 femoral revisions) of failed hip arthroplasty surgeries in department of orthopaedic surgery of Minia university and Queen Elizabeth university hospitals during January 2015 to January 2020. A total of seven femoral revisions were excluded as there was less than one-year follow-up. The preoperative pattern of bone loss was classified according to the method of Della Valle and Paprosky and the preoperative Cortical Index (CI) was also measured. Evaluation of the osteoporosis was assessed with the CI using diameter of the femoral diaphysis (x) and the internal diameter of medullary canal (y).
Posterolateral approach was used in 47 procedures, and lateral approach was used in 10 procedures. An extended trochanteric osteotomy (ETO) was indicated in the following scenarios
- Expected difficulties of cement mantle removal; distally extended thick cement mantle, bone or cement plug, eccentric stems and weakened cortices.
- Osteointigrated cementless stems.
- Cortical weakness or defects
- Curved femur that interferes with a straight reaming of femoral canal.
The TMFT stems were used to replace the initial stem and to achieve early reliable fixation on a relatively short intact isthmus as proximal as possible and as distal as necessary depending on the press-fit idea. Postoperatively all patients were permitted to fully weight- bear, utilizing walking aids for the first six weeks but instructed to avoid active abduction for first six weeks where an ETO was used. Functional outcomes were assessed using the HHS and OHS. A detailed radiographic analysis was evaluated on anteroposterior (AP) hip and lateral radiographs at day one and compared with the subsequent radiographs at three months, six months, one year, and annually thereafter. This radiographic analysis included evaluation of implant subsidence, stability and bone changes around the stem
In total, 50 femoral revisions (48 patients) with a mean age of 67.4±10.6 completed the follow-up. The mean follow-up time was 35.9 ± 15.6 months. Significant improvement was documented in the HHS and OHS (p<0.001). The mean HHS and OHS improved from 32.53±9.86 (14-60), 17.84±7.57 (6-36) at the preoperative evaluation to 86.66±8.29 (62-98), 34.20±8.23 (19-48) at the most recent follow-up. Subsidence of the femoral component was noticed predominantly in the first 3 months postoperatively (p<0.001). At three months follow-up, 34/50 stems subsided with mean subsidence of 3.36mm±4.6 (median, 2mm). At the 6 months follow-up measuring, only 5/34 stems showed further subsidence with mean subsidence 0.38mm±1.31 (p, 0.042). No further subsidence was noticed afterwards. This subsidence did not affect the functional outcome.
Femoral component integration showed satisfactory results. Osseointegration of the TM was evaluated as very good in 29 stems (58%), good in 14 stems (28%), and average in seven cases (14%). The latest follow-up radiographs were compared to the immediate post-operative radiographs and showed a significant bone restoration around the femoral components (p < 0.001). This bone restoration was independently from the severity of pre-operative bone insufficiency and was significantly positive correlated with the functional outcome.
In conclusion, uncemented TMFT stems can simplify the complex femoral revision surgery that is associated with variable degrees of femoral bone loss and short intact segment for initial fixation.
When bone-implant surface contact is obtained in a relatively short intact isthmus, these implants provide a reliable and durable solution for the management femoral revision hip surgery in different categories of proximal femoral bone loss.
The evidence of bone restoration with these implants encourage the use of such stems for the mechanically compromised proximal femur.
The ETO can be used safely to facilitate the surgery with no adverse effect on the bone restoration and implant subsidence.
The modularity in these implants provided the intraoperative flexibility for optimization of femoral version as well as the vertical and lateral offsets, therefore, we can obtain biomechanically stable joints.