Forty-six consecutive open reductions and internal fixations following primary or revised THA, which required fixation using a trochanteric claw plate for greater trochanteric fracture or osteotomy, were performed at our institution between January 2008 and December 2020. Of these, 5 patients (5 hips) were lost to follow-up (follow-up rate, 89%). The subjects included 13 men and 28 women, with a mean age of 68 years (range, 32–87 years) at the time of surgery. The mean duration of clinical follow-up was 4.2 years (range, 1–13 years). The trochanteric claw plate was used for trochanteric osteotomy in 6 hips, intraoperative fracture in 9 hips, and non-union, including postoperative fracture in 26 hips (Table 1). Non-union included dislocation in 8 hips, pain in 4 hips, transposition of fragment in 2 hips, limp in 1 hip, and fixation of the existing displaced trochanteric fragment from unrelated revision in 11 hips. The indication for managing a united greater trochanter was decided according to the Hamadouche’s algorithm, primarily based on the degree of limp, the magnitude of proximal migration of the greater trochanter, and pain (Fig. 1) [8]. Our institutional review board (2021152) approved this prospective cohort study. Each patient also provided informed consent for inclusion in the published findings.
Table 1
Pre-operative patient characteristics
Patient Demographics | Value |
Number of hips | 41 |
Mean age at surgery, years (range) | 68 (32 − 87) |
Sex, male:female | 13:28 |
Mean follow-up period, years (range) | 4.2 (1 − 13) |
Reason for the use of a trochanteric claw plate Trochanteric osteotomy Intra-operative fracture Non-union including post-operative fracture | 6 9 26 |
The trochanteric claw plate characteristics are as follows: 1) the proximal end has two hooks that capture the trochanteric fragment, and 2) the distal end has two convex flanges that appose to the femoral cortex (Fig. 2) [10]. In addition, each of these arms has one hole for flexible fixation to the femur with a 4.5 mm screw. The device is available in three sizes (80 mm, 90 mm, and 100 mm).
The transgluteal approach in the lateral position was used in all the patients. Furthermore, in revised THA, a longitudinal incision was made after incision through the skin and tensor fascia latae. Dislocation of the prosthesis was usually not required, and the trochanteric fragment and its femoral bed were cleaned of all fibrous or granulation tissue. Although the fixation of the trochanteric claw plate was performed according to previous reports [8, 11], we used an ultra-high molecular weight polyethylene fiber cable (UHMWPE fiber cable; NESPLON Cable System, Alfresa Pharma Co., Osaka, Japan) [12]. The hooks were pushed into the thickness of the gluteus medius tendon until they were in anterior contact with the trochanteric fragment. The claw plate in close contact with the trochanteric fragment was pulled down toward the distal, and the vastus lateralis was longitudinally incised to expose the subtrochanteric region. The UHMWPE fiber cable was circled around the claw plate. The plate was pulled down to the distal at the position of 20° of abduction, and then a 2.0 mm Kirshner wire was temporally fixed into the distal central hole. In cases of instability between the hooks and trochanteric fragment, a second UHMWPE fiber cable was circled over the hooks and trochanteric fragment. After the temporal fixation, the UHMWPE fiber cable was firmly tightened to a tension strength of approximately 20 kg. The cable was tied using a tensioning device (Alfresa Pharma Co.) with a double loop-sliding knot technique [13]. The fixation was then completed with two 4.5 mm bi-cortical screws placed anteriorly and posteriorly to the femur (Fig. 3). In our experience, the screw was sometimes fixed only in the posterior hole because the anterior femoral bone is narrow. Finally, a temporal Kirschner wire was removed, and the rigidity of the fixation was confirmed. Full weight-bearing was allowed as soon as possible, although the patients were encouraged to use a cane for up to 3 months.
After surgery, patients were followed-up at 2 weeks, 3 months, 6 months, 1 year, and annually thereafter. A retrospective analysis was performed by two blinded orthopedic surgeons. For clinical assessment, the Merle d’Aubigné and Postel grading system was used preoperatively and at the last follow-up [14]. Intraoperative and postoperative complications were also recorded. For radiological assessment, anteroposterior radiographs of the pelvis were evaluated using a ruler (Carestream Health Japan Co., Ltd., Tokyo, Japan). Trochanteric non-union was defined as visible migration of the trochanter. Union was considered to be complete when no residual radiolucent line was visible on the most recent anteroposterior views of the radiograph [10]. The apposition was considered good if the contact was perfect and there was no gap, fair if the gap was < 3 mm, and poor if it was ≥ 3 mm [8]. Statistical analysis was performed using nonparametric tests, with a p value < 0.05 considered statistically significant. Prosthesis survival was determined using the Kaplan -Meier method with 95% confidence intervals; end points were repeat revision surgery for implant breakage, non-union, dislocation, or pain. Data were analyzed using SAS 9.2 (SAS institute Inc., Cary, NC, USA).