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Abstract

Purpose:

To evaluate the clinical results of rigid fixation of the greater trochanter fragment through a consecutive hemiarthroplasty series using a cementless and modular calcar-replacement prosthesis with an integrated plate (MOD-Centaur stem) with 1-year follow-up in very elderly patients with unstable intertrochanteric fractures.

Methods:

We assessed 44 consecutive very elderly patients (age >85 years; 2 men, 42 women; mean age at surgery: 89.6 years) with an unstable intertrochanteric fracture who underwent bipolar hemiarthroplasty using the MOD-Centaur stem by the same surgeon. Operative time and blood loss were evaluated, and postoperative complications and mortality rate within 1 year were assessed. Bony union of the greater trochanter was evaluated using plain X-ray images at least 6 months postoperatively. Walking ability was evaluated at the time of discharge and at 1 year postoperatively.

Results:

The mean operative time was 95.8 min, and the mean intraoperative blood loss was 358.0 mL. Postoperative peripheral infection occurred in one patient. Four patients died within 1 year postoperatively (mortality rate: 9.1%). Bony union of the greater trochanter was achieved in all the patients who had a plain X-ray taken at least 6 months postoperatively. At 1-year follow-up, 20 patients could walk independently.

Conclusion:

Hemiarthroplasty using the MOD-Centaur stem for unstable intertrochanteric fracture in very elderly patients offers favorable outcomes. These findings encourage early walking without any loading limitations, despite severe osteoporosis, and emphasize the importance of greater trochanteric fixation, which reconstructs the mechanism of the gluteus medius muscle.

Keywords

clinical outcome gluteus medius greater trochanter hemiarthroplasty intertrochanteric fracture unstable fracture very elderly

Introduction

In Japan, a country with a high life expectancy,¹ the number of intertrochanteric fractures has been increasing among very elderly patients. This aging population has both poor bone quality and muscle weakness, and many very elderly patients have unstable fractures and have become bedridden.² Accordingly, the treatment of unstable intertrochanteric fractures in very elderly patients should ensure adequate pain relief and reliable early weight bearing. Osteosynthesis (including intramedullary and extramedullary fixation) has been mainly used for treating unstable intertrochanteric fractures.³ However, this procedure does not always allow for early ambulation postoperatively. In addition, the failure rate of osteosynthesis is as high as 20%, and the incidence of coxa vara, delayed healing, or nonunion is as high as 36–54%.^4,5

On the other hand, hemiarthroplasty has been reported mainly as a secondary salvage procedure for treating patients who experience failure of osteosynthesis.⁶ However, recently, the number of reports of hemiarthroplasty used as a primary treatment procedure for unstable fractures is gradually increasing because this technique can achieve both early mobilization and good hip function. In this context, very few reports have focused on the importance of the greater trochanter fragment in hemiarthroplasty. Rigid fixation of the greater trochanter is essential for reconstruction of the mechanism of the gluteus medius muscle that is required for standing. In addition, few studies have focused on hemiarthroplasty for this fracture in very elderly patients, despite the fact that unstable intertrochanteric fracture is particularly problematic for these patients due to their poor bone quality and muscle weakness. We hypothesize that the rigid fixation of the greater trochanter fragment leads to good clinical outcomes even in very elderly patients.

Therefore, the purpose of this study was to evaluate the clinical results of a consecutive series of hemiarthroplasty using a cementless and modular calcar-replacement prosthesis with an integrated plate, MOD-Centaur stem (KYOCERA Medical, Osaka, Japan), with a 1-year follow-up in very elderly patients with unstable intertrochanteric fractures.

Patients and methods

The institutional review board of our hospital approved this study.

Between October 2011 and December 2013, bipolar hemiarthroplasty was performed at our hospital for 44 consecutive very elderly patients with unstable intertrochanteric fracture (Jensen 3-fragment without posterolateral support in 21 cases; Jensen 4-fragment in 23 cases).⁷ All patients underwent bipolar hemiarthroplasty using the MOD-Centaur stem by the same surgeon. The patient group comprised 2 men and 42 women. The mean age at surgery was 89.6 years (range, 85–98 years). Preoperative conditions included heart disease (25 cases), dementia (18 cases), diabetes (3 cases), cerebrovascular disease (5 cases), and multiple combinations of these (28 cases). All the patients were able to walk independently before injury: 16 patients could walk without any support, 18 patients walked with a T-cane, and 10 patients walked with the help of a walker.

Implants and surgical techniques

The MOD-Centaur stem is a cementless modular calcar-replacement prosthesis with an integrated greater trochanter plate (GTP) to fix the greater trochanter fragment. As the concept of this prosthesis is proximal fixation in the metaphysis, the proximal body has an all-over hydroxyapatite coating. Due to the modular stem, it is easier to estimate the stability of the stem for bone loss of the femur than for the monoblock stem. However, this prosthesis is not suitable for use with subtrochanteric fractures, which have no cortical bone surrounding the subtrochanteric area. Lakstein et al.⁸ previously reported that the modular stem has a potential risk of fracture at the stem junction without proximal osseous support. Thus, this stem is also not suitable for the femur with its wide canal because the largest stem size available is up to 23 mm in diameter. The GTP and stem body are interlinked by two connectors, one with vertical rotation and the other with horizontal rotation. Therefore, the greater trochanter fracture fragment can be repositioned tightly back to the anatomical position. Each connecter is fixed with a tapered screw without wires. The stem length is designed for proximal femoral bowing of Japanese patients who have a short frame (Figure 1).

Figure 1.

The MOD-Centaur stem with the GTP. Two connectors enable the GTP to rotate in the vertical and horizontal directions for fixation of the greater trochanteric fracture fragment. GTP: greater trochanter plate.

The surgical technique involved conventional femoral neck surgery via a posterolateral approach in the lateral position, as follows. The piriformis, minor internal rotation muscles, and the quadratus femoris were released after carefully stopping any bleeding. After incising the joint capsule, the main fracture fragments including the greater and lesser trochanters, femoral shaft, and neck fragment were identified; then, the neck fragment was removed. If the lesser trochanter fragment was too small to fix, it was removed by cutting the iliopsoas tendon. The landmark of the lesser trochanter was helpful for determining the anteversion of the stem. If the landmark of the lesser trochanter was unclear, the transverse axis of the knee was used to decide stem anteversion. The dislocation stability and leg length were checked after reduction of the trial implant. Then, after assembling the appropriate stem body and distal stem, the prosthesis was carefully inserted. Initial stem fixation and proximal bone fitting should always be checked at this point. While the greater trochanter fracture was placed in the anatomical position, the GTP was joined with the stem body through the lower one-third of the gluteus medius muscle (Figure 2).

Figure 2.

Intraoperative image of the well-fixed greater trochanter through the gluteus muscle with GTP. The right side of the image corresponds to the patient’s cranial side and the upper side of the image is the patient’s anterior side. GTP: greater trochanter plate.

Clinical evaluation

Operative time and blood loss were evaluated intraoperatively. Postoperative complications were assessed carefully. Patients were allowed to walk with full weight bearing on postoperative day 2 after removal of the drainage tube. Patients received rehabilitation therapy at our hospital for 1 month, followed by additional rehabilitation therapy in a rehabilitation hospital for 1–3 months. Patients were scheduled to visit our hospital after discharge from the rehabilitation hospital. Plain X-ray images were obtained at least 6 months postoperatively to evaluate the bony union of the greater trochanter. For patients who did not visit our hospital, we conducted a telephone interview at 1 year postoperatively. Thus, no patients were lost to follow-up. Walking ability was evaluated at the time of discharge and at 1 year after surgery. To estimate the walking ability, patients who could walk independently were classified as “ambulatory,” while patients who needed assistance or a wheelchair to move were classified as “unable to walk.” We also investigated the mortality rate within 1 year postoperatively.

Results

The mean operative time was 95.8 min (range, 42–148 min) and the mean intraoperative blood loss was 358.0 mL (range, 64–685 mL). With regard to postoperative complications, one patient suffered peripheral infection, which needed reoperation for GTP removal at 10 months postoperatively. There were no cases of deep venous thromboembolism, pneumonia, or cerebral infarction. Postoperative plain X-ray images obtained at least 6 months postoperatively were available in 29 patients (65.9%), and bony union of the greater trochanter was observed in all 29 patients.

Changes in walking ability are shown in Figures 3 and 4. At the 1-year follow-up, 2 patients (4.5%) could walk without any support, 13 (29.5%) walked with a T-cane, 10 (22.7%) used a walker, and the remaining 15 (34.1%) were wheelchair-bound. Among the 10 patients who walked with a walker at the 1-year follow-up, 5 patients needed someone’s assistance to walk. Therefore, 20 patients were classified as “unable to walk.” Further, four patients died after discharge from our hospital within 1 year postoperatively. The mortality rate at the 1-year follow-up was thus 9.1%. Finally, excluding the patients who had died by the 1-year follow-up, 20 patients (50.0%) were ambulatory.

Figure 3.

Changes in the walking ability of patients.

Figure 4.

Changes in the classification of walking ability.

Case presentation

A 91-year-old woman sustained a Jensen 3-fragment intertrochanteric fracture without posterolateral support in a simple fall (Figure 5). She had hypertension and could walk independently without support before the injury. Hemiarthroplasty using the MOD-Centaur stem was performed 7 days after injury. The large greater trochanteric fragment was fixed with an integrated GTP. Walking exercise was started with a walker at 2 days after surgery. She could climb stairs holding a handrail and with assistance at 3 weeks after surgery (Figure 6). She could walk independently without any support at 1 year after surgery. Postoperative plain X-ray images at the 1-year follow-up revealed bone union of the greater trochanter (Figure 7).

Figure 5.

(a) Preoperative anteroposterior radiograph of a 91-year-old woman with a Jensen 3-fragment fracture without posterolateral support. (b) Preoperative posterior view of the three-dimensional CT image. (c) Preoperative anterior view of the three-dimensional CT image. CT: computed tomography.

Figure 6.

The patient could climb stairs 3 weeks after surgery.

Figure 7.

(a) Postoperative anteroposterior radiograph shows a well-fixed greater trochanteric fragment by integrated GTP. (b) Anteroposterior radiograph at 1 year after surgery shows union of the greater trochanteric fragment. GTP: greater trochanter plate.

Discussion

This study is the first study to describe the use of a cementless and modular calcar-replacement prosthesis with an integrated plate, the MOD-Centaur stem, for repair of intertrochanteric fractures in very elderly patients and to report the outcome of using this fairly novel stem implant. Our study has two major findings. First, hemiarthroplasty using the MOD-Centaur stem for intertrochanteric fractures achieved favorable patient outcomes with a high ambulatory rate (50%) and a low mortality rate (9.1%) even in a very elderly population. Second, bony union of the greater trochanter was observed on postoperative plain X-ray images obtained at least 6 months after surgery. These findings support our hypothesis that rigid fixation of the greater trochanter fragment leads to good clinical outcomes in very elderly patients.

In the treatment of intertrochanteric fracture, both relief from pain and recovery of the patient’s walking ability are crucial outcomes. To achieve these, most previous studies have suggested the new concept of implant use for reduction and fixation of unstable intertrochanteric fractures. Osteosynthesis for intertrochanteric fracture has been reported to offer good outcomes,^9,10 but it has also been associated with a number of mechanical failures, such as nonunion, cut-out, and implant fracture.^11,12 These mechanical failures directly affect walking ability and quality of life, especially in very elderly patients. Vaquero et al.¹³ treated intertrochanteric fracture by short femoral nailing using Gamma3 (Stryker, Mahwah, NJ, USA) and proximal femoral nail antirotation (Synthes GmbH, Oberdorf, Switzerland) and reported that the overall patient functional outcome was fair to poor based on Harris Hip Score categories. They also stated that the majority of patients with intertrochanteric fractures treated by short femoral nailing experienced many types of limitations in the activities of daily living at 1 year after sustaining the fracture. These unsatisfactory outcomes are of concern and may have been affected by muscle weakness, complications including dementia, and poor bone quality in very elderly patients. Moreover, poor bone quality is known to increase the proportion of unstable intertrochanteric fractures. Therefore, in the case of unstable intertrochanteric fracture, osteosynthesis may not be the best treatment option in very elderly patients because these patients can rarely undergo re-operation and the first operation is their only chance to walk again.

On the other hand, hemiarthroplasty has been reported as a secondary surgery for unstable intertrochanteric fracture¹⁴ as well as a primary surgery. Grimsrud et al.¹⁵ observed a trend toward lower re-operation rates with calcar-replacement hemiarthroplasty as compared with open reduction and internal fixation. Emami et al.¹⁶ compared outcomes in 30 cases of intertrochanteric fracture fixation with a dynamic hip screw (DHS) versus hemiarthroplasty and concluded that in elderly patients with concurrent medical conditions, reduction of the intertrochanteric fracture with the bipolar technique is more effective and less problematic than DHS and is better tolerated by patients because of improvements in functional status and the postoperative range of motion of the hip joint. Many other studies have also investigated the utility of bipolar hemiarthroplasty techniques for treating intertrochanteric fractures in elderly patients. Kumar et al.¹⁷ assessed the efficacy of cemented hemiarthroplasty for unstable intertrochanteric fracture in elderly patients (mean age, 72.4 years; range, 65–95 years) with severe osteoporosis. They fixed the greater trochanter by using a tension band wiring technique or by suturing near the prosthesis. Choy et al.¹⁸ used cementless hemiarthroplasty in elderly patients (mean age, 78.8 years; range, 70–95 years), with wires and nonabsorbable sutures to stabilize the greater trochanter.

Nevertheless, our greatest concern was that fixation of the greater trochanter by using a wiring technique would frequently lead to failure due to destruction of the wire or cheesy cutting of the femoral cortex. Recovery of walking ability is a key parameter for reconstruction of the greater trochanter in very elderly patients. Consequently, we selected the MOD-Centaur stem with an integrated GTP to maximize this possibility. The arm of the GTP is connected by straddling through the gluteus medius muscle, and the greater trochanter is thus fixed tightly between the GTP and the stem body. In the present series of very elderly patients in whom an intertrochanteric fracture was treated using the integrated GTP, 20 patients (50.0%) could walk independently at 1 year postoperatively. This result indicates that the MOD-Centaur stem enabled the greater trochanter fragment to achieve good fixation even in very elderly patients. Successful bony union was observed in all the radiographs obtained in this investigation. In addition, the modular system contributed to the excellent fitting of the stem. Careful preoperative selection of the possible proximal and distal implant sizes improves compatibility for different types of proximal femoral shapes.¹⁹ Thus, full, early weight bearing was possible in all patients postoperatively by ensuring strong support, provided by tight fixation of both the stem and the greater trochanter by a GTP integrated with the stem body.

In the very elderly population, hemiarthroplasty is a considerably invasive procedure that is associated with high blood loss, prolonged operative time, and high mortality. In our study, blood loss and operative time were similar to those in previous reports. Nevertheless, our mortality rate of 9.1% (4 cases) within 1 year following surgery was lower than that in previous reports, despite exclusively focusing on very elderly patients (Table 1). Shoda et al.²³ reported an in-hospital mortality rate of 3.3% after hip fracture in patients aged over 60 years and a significantly higher mortality rate among those treated conservatively. They also stated that surgically treated patients could start rehabilitation earlier and therefore avoid the complications caused by prolonged bed rest, such as bedsores, venous thromboembolism, atelectasis, and hypostatic pneumonia. Our results indicate that a low mortality rate depends on early standing and walking achieved through the strong support provided by the implant, rather than on a reduction in intraoperative stress. Moreover, the use of cementless implants might have reduced the mortality rate. Cankaya et al.²¹ reported that for unstable intertrochanteric fractures in elderly patients, the perioperative mortality rate was significantly lower in the cementless hemiarthroplasty group than in the cemented hemiarthroplasty group. They also stated that cementation affects mortality by elevating the intramedullary pressure, which leads to fat embolization. In very elderly patients with multiple underlying diseases, surgeons should attempt to eliminate factors that may potentially affect the mortality rate. In a previous study concerning intertrochanteric fractures, the large number of patients who withdrew before the final follow-up limited the findings.²⁴ Because elderly patients have many severe concurrent diseases, follow-up after discharge can be difficult. Our study followed up the patients as outpatients, and we also conducted telephone interviews with patients who could not attend follow-up. Therefore, our data is inclusive of patients who experienced poor results as well as those who experienced good results.

Table 1.

Comparison of bipolar hemiarthroplasty for intertrochanteric fractures.

	Hips	Patient age (range)	Greater trochanter fixation	Stem	Blood loss (cc)	Surgical time (min)	1-year mortality (%)
Gu et al.²⁰	15	85 (81–92)	Suture	Cemented	310	50	20.0
Cankaya et al.²¹	46	78 (66–95)	Dall–Miles cable	Cemented	540	89	45.7
Cankaya et al.²¹	40	76 (65–92)	Dall–Miles cable	Cementless	468	83	32.5
Kim et al.²²	29	82	Bolt and plate	Cementless	511	96	27.6
Emami et al.¹⁶	30	54.5	NR	Cementless	NR	NR	6.7
Current study	44	89.6 (85–98)	Integrated plate	Cementless	358	96	9.1

NR, not recorded.

This study has certain limitations. First, a comparative analysis with patients treated by osteosynthesis was not performed. Kim et al.²² reported a prospective, randomized comparative study between cementless calcar-replacement hemiarthroplasty and intramedullary fixation for unstable intertrochanteric fractures and showed that there were no significant differences in terms of functional outcomes, hospital stay, time to weight bearing, or general complications. Moreover, patients treated with intramedullary fixation had shorter operative time, lower blood loss, fewer units of blood transfused, lower mortality rate, and lower hospital costs. Nevertheless, it is premature to judge that osteosynthesis is a better treatment for intertrochanteric fracture in very elderly patients based on their findings. They used an optional trochanteric transfixing bolt and plate to fix the greater trochanter, and patient selection was not limited to the very elderly age group. A further prospective, comparative study is needed to evaluate the usefulness of the MOD-Centaur stem for treating intertrochanteric fractures, especially in very elderly patients. Second, an objective evaluation of osteoporosis was not performed in the present study. However, as all of our patients were over 85 years of age, we expected osteoporosis in our patients to be more severe than that in patients from previous studies. Third, the follow-up period was not long term but only 1 year after surgery. We recognize that it is important to evaluate the long-term results of this stem implant in terms of clinical and radiological analyses, survival rate, and future use of this stem. However, for very elderly patients, evaluating the first 1-year outcome with a high follow-up rate is crucial. Therefore, we consider that our data would be informative for discussing the optimal treatment of intertrochanteric fractures in very elderly patients.

Conclusion

Hemiarthroplasty using the MOD-Centaur stem for unstable intertrochanteric fractures in 44 very elderly patients (over 85 years of age) resulted in an acceptable ambulatory rate and low mortality rate postoperatively. The procedure offered favorable outcomes for very elderly patients with severe osteoporosis. These findings encourage early walking without any loading limitations postoperatively and highlight the importance of greater trochanteric fixation, which reconstructs the mechanism of the gluteus medius muscle.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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Cementless calcar-replacement stem with integrated greater trochanter plate for unstable intertrochanteric fracture in very elderly patients