The Journal of Arthroplasty xxx (2015) xxx–xxx
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The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up Tomomi Kamada, MD a, Hiroshi Imai, PhD a, Naohiko Mashima, PhD a, Jun Takeba, PhD a, Hideo Okumura, PhD b, Hiromasa Miura, PhD a a b
Department of Bone and Joint Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan Department of Orthopaedic Surgery, Rakuyo Hospital, Sakyo-ku, Kyoto, Japan
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Article history: Received 11 September 2014 Received in revised form 2 December 2014 Accepted 28 December 2014 Available online xxxx Keywords: interlocking cementless stem revision total hip arthroplasty femoral stem survival proximal bone defect bone ingrowth
a b s t r a c t Stem fixation is difficult to achieve in severe proximal bone loss in revision hip surgery. In this study, we sought to present the results of distally-locked stem with screws (HUCKESTEP HIP stem) in 21 revision hips with mean follow-up period of 15 years. The preoperative mean Japanese Orthopaedic Association hip score had improved from 54 to 75 points. Further revisions were required for 2 stems, in one because of infection and the other because of screws fracture and subsidence. With removal of the stem for any reason as an end-point, the cumulative survival at 15 years was 90.4%. While this study had small number, the use of this interlocking stem for revision hips with extensive proximal bone defects provided satisfactory 15-year clinical and radiographic results. © 2015 Elsevier Inc. All rights reserved.
Stem fixation is difficult to achieve in certain cases of femoral stem revision performed secondary to osteolysis or a periprosthetic femoral bone fracture because of the presence of extensive bone defects in the proximal femur. The HUCKSTEP HIP (B. Braun-Aesculap, Tuttlingen, Germany) system is derived from the titanium alloy intramedullary nail fixation designed for the treatment of femoral comminuted fractures by Huckstep et al in 1967 [1,2] and is composed of a distally locked stem with screws at the proximal and distal ends. This system has been used in cases of stem revision performed secondary to loosening or severe osteolysis at the proximal femur and in those in which proximal fixation is not feasible due to reasons such as a periprosthetic fracture. We conducted this study to establish the mid- to long-term clinical and radiographic results of the use of this interlocking femoral stem used in revision total hip arthroplasty with proximal femoral bone defects. Materials and Methods This study was approved by the local institutional review boards and performed in accordance with the ethical standards of the 2000 revised version of the Declaration of Helsinki (original version 1964). All patients provided informed consent for participation in the clinical trial. Between 1993 and 2002, we performed revision total hip arthroplasty in 50 patients. Among them, we used an interlocking femoral stem in The Conflict of Interest statement associated with this article can be found at http:// dx.doi.org/10.1016/j.arth.2014.12.023. Reprint requests: Kamada Tomomi, MD, Department of Bone and Joint Surgery, Ehime University Graduate School of Medicine, Shitukawa, Toon, Ehime, 791–0295, Japan.
41 hips of 40 patients who had proximal femoral bone loss (Paprosky type 2 defect or higher) and in whom it was difficult to obtain proximal fixation. Patients who were lost to follow-up or who died were excluded. This was a consecutive series of unselected patients and included all patients undergoing this surgery. The HUCKSTEP HIP stem (Fig. 1) is a straight stem made of a titanium alloy with a circumferential porous coating on the proximal surface of the stem. The stem is available in a diameter of 12.5 mm only and in 4 different lengths: 160, 210, 260, and 320 mm. The proximal stem section has 2 holes for 4.5-mm diameter screws running from anterior to posterior. At the distal stem section, the 160-mm long stem has 3 holes, and the rest have 6 holes running from lateral to medial, for screw insertion. This distal mechanism of fixation permits an exact restoration of lower limb length and provides the initial axial and rotational stability. All surgeries were performed by one senior surgeon. Intraoperatively, the femoral implant was removed and the canal debrided of fibrous tissue, following which reaming was performed with flexible bone reamers and by gradually increasing their thickness to 13 mm in 1 mm increments. The reaming was performed using the mini C-arm image intensifier to ensure that the anterior cortex at the femoral bow was not violated. This was followed by rasping. The prosthesis holder and targeting instrumentation were fixed to the stem and introduced into the canal without strong hammering. Trial reduction was performed after positioning of the trial components to check for leg length, anteversion, and stability in all directions. Definitive components were then implanted. The proximal and distal screws were then locked using the targeting device. Finally, an adequate amount of bone graft was used to fill the bone defects in the medullary cavity (Fig. 1). The
http://dx.doi.org/10.1016/j.arth.2014.12.023 0883-5403/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
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T. Kamada et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
Fig. 1. Photograph of the HUCKSTEP HIP stem.
autologous bone grafts mixed with fresh-frozen allografts taken from femoral heads of other patients and apatite-wollastonite glass ceramic (AW-GC) were used in all hips to reconstruct the bone defects in the proximal femurs and medullary cavity. The fresh-frozen femoral heads were prepared by milling large particles in a bone mill and washing with AW-GC particles used as allografts. The bone grafting was performed according to the method described by Kim et al [3]. The morselized bone was packed into the bone defect as much as possible. Furthermore, the cortical autograft was held to the bone defect by steel wires, and the gap between the bone defect and cortical autograft was filled with the morselized cancellous autografts and allografts. Postoperatively, partial weight-bearing was encouraged for 3 months and then more weight-bearing with crutch walking was recommended for the following 3 months. Full weight-bearing was permitted 6 months after surgery. Clinical assessment was performed by two of the authors who were not the operating surgeon and who had over 20 years of experience. Additionally, they were blinded to the radiographic result at the time of the evaluation. Clinical assessment of hip joint function was performed preoperatively and at the most recent follow-up using the Japanese Orthopaedic Association (JOA) hip score [4]. The JOA Hip Score is a 100-point scale that comprises the subcategories of pain (0–40 points), range of motion (ROM; 0–20 points), ability to walk (gait; 0–20 points), and activities of daily living (ADL; 0–20 points). The maximum total score for a normal hip is 100 points, and high scores indicate better function. Patients with a good result achieved a score of ≥ 70 points. The final follow-up and preoperative scores were compared. Patients were carefully monitored for development of complications including dislocation, infection, fracture, sciatic nerve palsy, and deep venous thrombosis. The most recent radiographs were reviewed and compared with the initial postoperative radiographs. Two experienced examiners who were not the operating surgeon and who were blinded to the patient characteristics reviewed all radiographs and made all radiographic observations. Standardized images of the hip with the femur in the anteroposterior and lateral planes were obtained with a standard tube to cassette distance of 115 cm. The degree of preoperative bone loss was recorded as described by Paprosky et al [5]. Radiographs were
assessed for loosening, stable fixation, or bone ingrowth around the prosthesis based on criteria described by Engh et al [6]. Radiolucencies along the metal-bone interface were documented based on a modification of the method described by Gruen et al [7]. Stress shielding was assessed on the basis of bone density according to the criteria described by Moreland and Moreno [8]. Briefly, minimal stress shielding was indicated by little or no change in cortical density. Moderate stress shielding was indicated by significant and obvious loss of cortical density and thickness, whereas severe stress shielding was indicated by major, striking, and an impressive degree of bone loss. Cortical hypertrophy and osteolytic changes in cancellous bone density were recorded. Subsidence was measured using the Callaghan et al technique [9]. A movement of 3 mm or more was evaluated as subsidence, or alternatively, subsidence was regarded as definitely having occurred if the interlocking screws had broken. The osteotomy site in patients who had a bone fracture before surgery was considered as having healed radiologically if callus was seen bridging the site in the anteroposterior and lateral planes according to Chen et al [10]. The degree of stem filling was determined by the method developed by Mertl et al [11]. Stem filling was described as the ratio of stem diameter to femoral canal diameter 2 cm below the lesser trochanter, and referred to as the metaphyseal filling index (MFI). The presence or absence of screw fracture was determined. Failures were defined as stem removal, stem revision, stem migration over 5 mm, or extended osteolysis. The data were stored until review by an independent blinded observer. Statistical analyses were conducted using the JMP 11 (SAS Institute Inc., Cary, NC, USA). The data were analyzed using the Wilcoxon rank sum test. The level of significance was set at P b 0.05. Survivorship was calculated using the Kaplan–Meier analysis, with removal of the component for any reason as the criterion for failure. Survivorship data and 95% confidence intervals (CI) are presented with P b 0.05 considered as being significant.
Results Of the 40 consecutive patients (41 hips) enrolled, 2 were lost to follow-up, and 18 died of causes unrelated to the surgery. The remaining 20 patients (21 hips) were included in the study. A telephone interview with a standardized questionnaire, including the JOA score items, was conducted for 2 patients as they did not have a yearly follow-up visit and were not willing to come to the institution personally. Radiographic analysis could not be performed in these patients. The study participants included 6 men and 14 men (mean age at surgery, 62 years [range, 26–74]) with a mean follow-up duration of 15 years (range, 12–20). The diagnosis at the time of the primary hip replacement in these patients was developmental dysplasia of the hip in 14 patients (15 hips), fracture in 4 patients (4 hips), and femoral head necrosis in 2 patients (2 hips). Nineteen patients (20 hips) had undergone only 1 hip arthroplasty in the same hip before the revision and 1 patient (1 hip) had undergone 2 previous arthroplasties. The indication for the index revision was aseptic loosening of the cemented total hip arthroplasty in 11 hips (both components in 10 hips and only femoral component in 1 hip), failed hemi-replacement arthroplasty in 7 hips (aseptic loosening of the stem with migration), infected cemented bipolar prosthesis in 1 hip, and peri-prosthetic and prosthetic fracture in 2 hips. The length of the HUCKSTEP HIP stems used in the present study was 160 mm in 3 hips, 210 mm in 3 hips, and 260 mm in 15 hips. Both the femoral and the acetabular components were revised in 20 hips, and only the femoral component was revised in 1 hip. Exposure was achieved using a transfemoral osteotomy in 3 hips and a posterolateral approach in the remaining 18 hips. A transverse osteotomy for the correction of angular deformity in the diaphysis was performed in 4 hips. The bone defects in the medullary cavity were grafted with autologous bone chips and artificial bone granules in 11 hips, with allograft and artificial bone granules in 8 hips, and with only artificial bone in 2 hips (Fig. 2).
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
T. Kamada et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
The JOA hip score improved from 54 points (range, 15–73) preoperatively to 75 points (range, 47–82) at the final follow up, thereby showing a significant improvement (P b 0.05). This was considered a good clinical result, with a JOA score of ≥70 points. Postoperative dislocation occurred in 2 hips, both of which were reduced non-invasively. Postoperative infection occurred in 1 patient. Intraoperative fractures occurred in 4 hips (19%). Minor cracks were noted in the calcar region of 3 hips, and 1 crack was noted in the diaphyseal area. We used steel wires to secure the cracks, and all cracks healed without any complications. In one (33%) of the patients treated using the transfemoral approach, synostosis failure of the greater trochanter occurred, and invasive reduction was performed. One patient sustained a periprosthetic fracture distal to the tip of the prosthesis without loosening (Vancouver type-B fracture) 8 years after the surgery. This patient was successfully treated with open reduction internal fixation by plate osteosynthesis. None of the patients had sciatic nerve injury and deep venous thrombosis. Among the 21 hips, 8 were categorized as Paprosky type II deficiencies, 7 as type IIIA, 4 as type IIIB, and 2 as type IV. According to the Engh et al [6] classification concerning the biologic stem fixation, stable fixation was observed in 20 hips, and unstable fixation was observed in 1 hip with stem loosening. Nine hips presented with a radiolucent line in the distal stem section. Moderate stress shielding in the proximal section was noted in 15 hips. Cortical hypertrophy was observed around the distal screws in 11 hips. None of the hips demonstrated osteolysis. Subsidence occurred in 1 hip. In all of the 4 hips that underwent femoral osteotomy at the time of stem insertion and in the 2 hips in which a bone fracture had occurred before surgery, synostosis was achieved within 1 year after surgery. The mean MFI was 67% (range, 51–80%). Fracture of screw occurred in 2 hips (9.5%). In one of these, 1 screw broke 7 years after surgery. However, the screw fracture did not cause any symptoms, and no treatment was required. In the other hip, 4 screws broke 5 years after surgery leading to loosening and stem removal. No association was observed between MFI and stem failure. Stem failure was observed in 2 hips in which the stem was revised secondary to infection and removed due to subsidence. One of these patients was a 43-year-old man with a 14-year history of hemodialysis (Fig. 3A–D). He underwent femoral head arthroplasty with cement for
Fig. 2. The radiographs illustrate the case of a 50-year-old woman with revision of a loose stem and cup after 14 years. (A) The preoperative radiograph shows the loose acetabular cup and stems with a proximal bone defect type Paprosky IIIA. (B) The radiograph shows the hip 3 weeks after revision with implantation of a cementless press-fit cup and a HUCKSTEP hip stem with distal locking screws implanted by a posterior approach. (C) The radiograph shows the hip 20 years after surgery. The revision stem is unchanged and the interlocking screws are still intact. The proximal femoral bone shows mild stress shielding and cortical hypertrophy was observed around the distal screws.
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femoral head necrosis. Five years later, loosening occurred, and revision was performed with this stem. Five years after the revision, the screws broke followed by stem migration. Thus, the stem was removed. In the second case, this stem was removed because infection occurred 6 years after surgery. A sufficient amount of bone regeneration had occurred so that the stem could be exchanged for a shorter stem. The Kaplan–Meier stem survival rate was 90.4% (95% CI: 68.8%– 97.6%) at 15 years with femoral component revision for any reason as the end point (Fig. 4), and 90.2% (95% CI: 68.1%–97.5%) at 15 years with stem loosening and screw breakage as the end point (Fig. 5). Discussion The mid- to long-term clinical and radiographic outcomes of interlocking femoral stem use were found to be excellent. Favorable long-term outcomes were also achieved by these stems in cases classified as IIIB or IV according to the Paprosky classification. Proximal femoral bone defects are frequently present in those requiring hip replacement revisions due to stem loosening or a prosthetic fracture. The stem revision methods applied in cases of extensive bone defects or deficient isthmus include cemented revisions of femoral components [12], use of an extensively porous-coated stem, impaction allografting with long cementless stems, total femur arthroplasty, and use of a distal interlocking stem. However, Schmale et al [13] report that the results of the cemented revision of femoral components were unpredictable and that the intermediate results were discouraging. Distally fixed, extensively porous-coated stems are reported to be associated with high failure rates [14,15]. Cameron et al [16] report that primary fixation is difficult to achieve in cases of severe bone defects, which provide a poor biological and mechanical environment for proximal porous ingrowth. Furthermore, Harris et al [17] have provided the following description: “High stresses at the termination of the porous coating, where the dense cortical bone ingrowth occurs, with the resultant cantilever forces could lead to stem fracture, periprosthetic fracture, thigh pain, and late component loosening due to debonding and extrusion of the porous coating. Furthermore, proximal bone loss owing to stress shielding can predispose the patient to proximal periprosthetic fractures and also complicate further revision.” In addition, previous studies have reported the results of revision hip arthroplasty using the Wagner stem. Regis et al [18] reported a high rate of complications including subsidence and dislocation (significant subsidence was observed in ≥10% of the hips). They considered the inadequate offset of the Wagner SL design to be primarily responsible for this problem. Moreover, Pekkarinen et al [19] describe that impaction bone grafting is more likely to cause bone fractures in patients with bone defects or thin cortical bone. While total femur arthroplasty is a complicated surgical procedure, it is also reported to be associated with high infection rates and to cause functional limitations after surgery [20,21]. In order to achieve fixation with a cementless stem even in those with bone defects, a stem with distal interlocking screws is used [12,22–26]. This interlocking femoral stem used in the present study is derived from the titanium intramedullary nail fixation designed for the treatment of femoral comminuted fractures by Huckstep et al in 1967 [1,2]. This stem went out of production in 2010. This system is composed of a straight long stem with circumferential porous coating at the proximal section and interlocking screws at the proximal and distal sections. The interlocking screws were useful in providing early rotational and axial stability, and the calcar replacing prosthesis obviated the need for allograft reconstruction in hips with deficient calcar. In addition, the interlocking screws increase fixation stability of the porous implant, which may help to prevent implant loosening and subsequent periprosthetic fracture and subsidence. In our study subjects, no spot welds were observed around the proximal part of the porous surface and the stems were fibrous stable; however, no periprosthetic fracture or subsidence resulting from loosening occurred in any patient. Although all the stems had a diameter of 12.5 mm and thin cortical bone was observed, none of the
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
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T. Kamada et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
Fig. 3. The radiographs illustrate the case of a 43-year-old man on hemodialysis with revision of a cemented hip prosthesis. (A) The preoperative radiograph shows the loose acetabular cup and radiolucent around the cement at the proximal femur with a bone defect type Paprosky II. (B) The radiograph shows the hip 4 weeks after revision total hip arthroplasty. Six distal interlocking screws were inserted to provide additional stability. (C) The radiograph taken 5 years after surgery shows breakage of the interlocking screws because stem fixation only depended on the interlocking screws. (D) Photograph of removal screws. All screws had broken.
Fig. 4. Kaplan–Meier survival curve for all patients with failure for any reason as the end-point.
patients experienced a fracture. Mahomed et al [22] reported that distal interlocking increased the torsional stability by 320% and axial stability by 230%. In addition, compared to an extensively porous-coated stem, it is also easier to remove and causes fewer new bone defects. Meanwhile, there is a concern that because the load is mainly transmitted by distal screws, stress shielding may occur in the proximal cortical bone. Fink
Fig. 5. Kaplan–Meier survival curve for all patients with failure for aseptic loosening and screw fracture as the end-point.
et al [27] have reported that the use of long distally fixed stems in osteoporotic bones resulted in a stress-shielding effect, which can be regarded as a disadvantage. Paprosky et al [28] reported that proximal stress shielding is a lesser concern in revision surgery because predictable biologic fixation and longevity of implant survival take precedence over the stress shielding of an already deficient proximal femoral bone; the clinical significance of stress shielding should also be considered in revision surgery using the distal fixation method. In the present study, mild stress shielding was found in 10 hips (47%), whereas severe stress shielding of the proximal femur was not seen in any of the hips during the minimum follow-up period of 12 years. Only the interlocking femoral stem with a diameter of 12.5-mm was used. We consider the absence of severe stress shielding, even in the long-term follow-up, to be attributable to the thinner stem being thinner than the medullary cavity. Moreover, it is also reported that when a distal locking stem is used, insufficient bone ingrowth at the proximal section causes stress on distal screws, which in turn may break. Sotereanos et al [23] reported a single instance of stem subsidence and loosening in which the stem was too thin for adequate bony contact and fixation to occur. The interlocking screws also broke at more or less the same time after surgery because they were the sole source of fixation and stability in the revised prosthesis. Furthermore, Learmonth [24], who performed stem revision using interlocking screws for periprosthetic fractures of Vancouver type B2, reported breaking of the interlocking screws, resulting in subsidence of 5 mm or more in 5 out of 22 hips. The reported reason for this was that the chosen stem was too thin in the distal region. However, we assume that the model used by Learmonth, which uses 2 distal screws, is inferior in the strength of distal fixation to this interlocking femoral stem. Mertl et al [11] report that an MFI of 75% or below is associated with a 10-fold increased risk of screw fractures and subsidence. In the present study, the mean MFI was 67%, and MFI in patients with stem loosening was lower at 51%. However, no association was observed between screw fractures and MFI. The patient with stem migration was receiving dialysis and oral steroid therapy. Previous studies that examined the results of total hip arthroplasty in hemodialysis patients have reported early loosening. Naito et al [29] reported a loosening rate of 35% at 5 years and attributed this high failure rate to poor bone quality caused by renal osteodystrophy. Moreover, Toomey and Toomey [30] noted that loosening had occurred in 58% of cemented stems in a long-term follow-up study. In a patient with stem migration in the present study, we assume that although the bone prosthesis was implanted in the bone defects in the medullary cavity,
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
T. Kamada et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
bone ingrowth did not occur in the porous-coated section due to abnormal bone metabolism and amyloid deposition caused by long-term hemodialysis resulting in stem migration. In this series, cortical hypertrophy around the distal interlocking screws was seen in 16 hips (76%). Spot welds in the proximal porouscoated section were not confirmed in any of the patients, and stable fibrous fixation was achieved in all patients. Although screws provide stable fixation, there was no proximal osseointegration. Therefore, no bone ingrowth was observed, and this increased the risk of screw breakage in the future. Because this imposes a load on the distal screw section for a long period of time, we consider that distal screws should be inserted wherever possible. Furthermore, we did not remove the screws and left them in the implants during the follow-up period. We also consider that bone graft in the medullary cavity contributed to the achievement of stable fibrous fixation. In recent years, newer interlocking femoral stems have been developed; the first one was with HA coating on the proximal porous surface for successful bone ingrowth, the second with a larger porous surface area, and the third with a variation in stem size for reducing the load placed on the screws [10]. Our cumulative survival rate for this implant at 15 years is comparable with that of other revision stems used in similar situations [25,31]. Sexton et al [25] have reported cumulative survival rates of distal interlocking straight stems with 6–13 screw holes at the distal section (Kent) as 93% at 5 years, 89% at 10 years, and 77% at 15 years. In our study, the cumulative survival rate at 15 years was 90.4%, which was comparable to the above, and this also compares favorably with many of the other prostheses used in this type of a patient [32,33]. We recognize the limitations of our study, which include its retrospective nature, the small number of patients, and the lack of a control group undergoing an alternative treatment. Nevertheless, the use of a distal interlocking stem, even in cases of extensive femoral bone defects, facilitated salvage and achieved stable long-term outcomes. Although there is a risk of screw fractures or subsidence in cases without biologic osteointegration, we consider this interlocking femoral stem to play a critical role in the treatment of cases with extensive proximal bone defects, which render stem fixation difficult and in the treatment of those with a periprosthetic fracture. References 1. Huckstep RL. The Huckstep intramedullary compression nail. Indications, technique, and results. Clin Orthop Relat Res 1986;212:48. 2. Huckstep RL. Stabilization and prosthetic replacement in difficult fractures and bone tumors. Clin Orthop Relat Res 1987;224:12. 3. Kim YM, Kim HJ, Song WS, et al. Experiences with the BiCONTACT revision stems with distal interlocking. J Arthroplasty 2004;19:27. 4. Hasegawa Y, Iwata H, Mizuno M, et al. The natural course of osteoarthritis of the hip due to subluxation or acetabular dysplasia. Arch Orthop Trauma Surg 1992;111:187.
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5. Paprosky WG, Burnett RS. Assessment and classification of bone stock deficiency in revision total hip arthroplasty. Am J Orthop 2002;31:459. 6. Engh CA, Massin P, Suthers KE. Roentgenographic assessment of the biologic fixation of porous-surfaced femoral components. Clin Orthop Relat Res 1990;257:107. 7. Gruen TA, McNeice GM, Amstutz HC. “Modes of failure” of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop Relat Res 1979;141:17. 8. Moreland JR, Moreno MA. Cementless femoral revision arthroplasty of the hip: minimum 5 years follow up. Clin Orthop Relat Res 2001;393:194. 9. Callaghan JJ, Salvati EA, Pellicci PM, et al. Results of revision for mechanical failure after cemented total hip replacement, 1979 to 1982. A two to five-year follow-up. J Bone Joint Surg Am 1985;67:1074. 10. Chen WM, McAuley JP, Engh Jr CA, et al. Extended slide trochanteric osteotomy for revision total hip arthroplasty. J Bone Joint Surg Am 2000;82:1215. 11. Mertl P, Philippot R, Rosset P, et al. Distal locking stem for revision femoral loosening and periprosthetic fractures. Int Orthop 2011;35:275. 12. Eisler T, Svensson O, Iyer V, et al. Revision total hip arthroplasty using third generation cementing technique. J Arthroplasty 2000;15:974. 13. Schmale GA, Lachiewicz PF, Kelley SS. Early failure of revision total hip arthroplasty with cemented precoated femoral components: comparison with uncemented components at 2 to 8 years. J Arthroplasty 2000;15:718. 14. Weeden SH, Paprosky WG. Minimal 11-year follow-up of extensively porous-coated stems in femoral revision total hip arthroplasty. J Arthroplasty 2002;17:134. 15. Hamilton WG, Cashen DV, Ho H, et al. Extensively porous-coated stems for femoral revision. A choice for all seasons. J Arthroplasty 2007;22:106. 16. Cameron HU. The long-term success of modular proximal fixation stems in revision total hip arthroplasty. J Arthroplasty 2002;17:138. 17. Harris WH. Will stress shielding limit the longevity of cemented femoral components of total hip replacement? Clin Orthop Relat Res 1992;274:120. 18. Regis D, Sandri A, Bonetti I, et al. Femoral revision with the Wagner tapered stem. A ten- to 15-year follow-up study. J Bone Joint Surg (Br) 2011;93-B:1320. 19. Pekkarinen J, Alho A, Lepisto J, et al. Impaction bone grafting in revision hip surgery: a high incidence of complications. J Bone Joint Surg (Br) 2000;82:103. 20. Friesecke C, Plutat J, Block A. Revision arthroplasty with use of a total femur prosthesis. J Bone Joint Surg Am 2005;87:2693. 21. Parvizi J, Sim FH. Proximal femoral replacement with megaprostheses. Clin Orthop Relat Res 2004;420:169. 22. Mahomed N, Schatzker J, Hearn T. Biomechanical analysis of a distally interlocked press-fit femoral total hip prosthesis. J Arthroplasty 1993;8:129. 23. Sotereanos N, Sewecke J, Raukar GJ, et al. Revision total hip arthroplasty with a custom cementless stem with distal cross-locking screws. Early results in femora with large proximal segmental deficiencies. J Bone Joint Surg Am 2006;88:1079. 24. Learmonth ID. The management of periprosthetic fractures around the femoral stem. J Bone Joint Surg (Br) 2004;86:13. 25. Sexton SA, Stossel CA, Haddad FS. The Kent hip prosthesis: an evaluation of 145 prostheses after a mean of 5.1 years. J Bone Joint Surg (Br) 2006;88-B:310. 26. Bernd F, Grossmann A, Fuerst M. Distal interlocking screws with a modular revision stem for revision total hip arthroplasty in severe bone defects. J Arthroplasty 2010;25:759. 27. Fink B, Grossmann A. Modified transfemoral approach to revision arthroplasty with uncemented modular revision stems. Oper Orthop Traumatol 2007;19:32. 28. Paprosky WG, Greidanus NV, Antoniou J. Minimum 10-year-results of extensively porous-coated stems in revision hip arthroplasty. Clin Orthop Relat Res 1999;369:230. 29. Naito M, Ogata K, Shiota E, et al. Hip arthroplasty in haemodialysis patients. J Bone Joint Surg (Br) 1994;76:428. 30. Toomey HE, Toomey SD. Hip arthroplasty in chronic dialysis patients. J Arthroplasty 1998;13:647. 31. Volkmann R, Bretschneider C, Eingartner C, et al. Revision arthroplasty–femoral aspect: the concept to solve high grade defects. Int Orthop 2003;27(Suppl. 1):24. 32. Chandler H, Clark J, Murphy S, et al. Reconstruction of major segmental loss of the proximal femur in revision total hip arthroplasty. Clin Orthop Relat Res 1994;298:67. 33. Maron MC. Treatment of periprosthetic fractures around total hip arthroplasty with an extensively coated femoral component. J Arthroplasty 1996;11:981.
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
Contents lists available at ScienceDirect
The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org
Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up Tomomi Kamada, MD a, Hiroshi Imai, PhD a, Naohiko Mashima, PhD a, Jun Takeba, PhD a, Hideo Okumura, PhD b, Hiromasa Miura, PhD a a b
Department of Bone and Joint Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan Department of Orthopaedic Surgery, Rakuyo Hospital, Sakyo-ku, Kyoto, Japan
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Article history: Received 11 September 2014 Received in revised form 2 December 2014 Accepted 28 December 2014 Available online xxxx Keywords: interlocking cementless stem revision total hip arthroplasty femoral stem survival proximal bone defect bone ingrowth
a b s t r a c t Stem fixation is difficult to achieve in severe proximal bone loss in revision hip surgery. In this study, we sought to present the results of distally-locked stem with screws (HUCKESTEP HIP stem) in 21 revision hips with mean follow-up period of 15 years. The preoperative mean Japanese Orthopaedic Association hip score had improved from 54 to 75 points. Further revisions were required for 2 stems, in one because of infection and the other because of screws fracture and subsidence. With removal of the stem for any reason as an end-point, the cumulative survival at 15 years was 90.4%. While this study had small number, the use of this interlocking stem for revision hips with extensive proximal bone defects provided satisfactory 15-year clinical and radiographic results. © 2015 Elsevier Inc. All rights reserved.
Stem fixation is difficult to achieve in certain cases of femoral stem revision performed secondary to osteolysis or a periprosthetic femoral bone fracture because of the presence of extensive bone defects in the proximal femur. The HUCKSTEP HIP (B. Braun-Aesculap, Tuttlingen, Germany) system is derived from the titanium alloy intramedullary nail fixation designed for the treatment of femoral comminuted fractures by Huckstep et al in 1967 [1,2] and is composed of a distally locked stem with screws at the proximal and distal ends. This system has been used in cases of stem revision performed secondary to loosening or severe osteolysis at the proximal femur and in those in which proximal fixation is not feasible due to reasons such as a periprosthetic fracture. We conducted this study to establish the mid- to long-term clinical and radiographic results of the use of this interlocking femoral stem used in revision total hip arthroplasty with proximal femoral bone defects. Materials and Methods This study was approved by the local institutional review boards and performed in accordance with the ethical standards of the 2000 revised version of the Declaration of Helsinki (original version 1964). All patients provided informed consent for participation in the clinical trial. Between 1993 and 2002, we performed revision total hip arthroplasty in 50 patients. Among them, we used an interlocking femoral stem in The Conflict of Interest statement associated with this article can be found at http:// dx.doi.org/10.1016/j.arth.2014.12.023. Reprint requests: Kamada Tomomi, MD, Department of Bone and Joint Surgery, Ehime University Graduate School of Medicine, Shitukawa, Toon, Ehime, 791–0295, Japan.
41 hips of 40 patients who had proximal femoral bone loss (Paprosky type 2 defect or higher) and in whom it was difficult to obtain proximal fixation. Patients who were lost to follow-up or who died were excluded. This was a consecutive series of unselected patients and included all patients undergoing this surgery. The HUCKSTEP HIP stem (Fig. 1) is a straight stem made of a titanium alloy with a circumferential porous coating on the proximal surface of the stem. The stem is available in a diameter of 12.5 mm only and in 4 different lengths: 160, 210, 260, and 320 mm. The proximal stem section has 2 holes for 4.5-mm diameter screws running from anterior to posterior. At the distal stem section, the 160-mm long stem has 3 holes, and the rest have 6 holes running from lateral to medial, for screw insertion. This distal mechanism of fixation permits an exact restoration of lower limb length and provides the initial axial and rotational stability. All surgeries were performed by one senior surgeon. Intraoperatively, the femoral implant was removed and the canal debrided of fibrous tissue, following which reaming was performed with flexible bone reamers and by gradually increasing their thickness to 13 mm in 1 mm increments. The reaming was performed using the mini C-arm image intensifier to ensure that the anterior cortex at the femoral bow was not violated. This was followed by rasping. The prosthesis holder and targeting instrumentation were fixed to the stem and introduced into the canal without strong hammering. Trial reduction was performed after positioning of the trial components to check for leg length, anteversion, and stability in all directions. Definitive components were then implanted. The proximal and distal screws were then locked using the targeting device. Finally, an adequate amount of bone graft was used to fill the bone defects in the medullary cavity (Fig. 1). The
http://dx.doi.org/10.1016/j.arth.2014.12.023 0883-5403/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
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T. Kamada et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
Fig. 1. Photograph of the HUCKSTEP HIP stem.
autologous bone grafts mixed with fresh-frozen allografts taken from femoral heads of other patients and apatite-wollastonite glass ceramic (AW-GC) were used in all hips to reconstruct the bone defects in the proximal femurs and medullary cavity. The fresh-frozen femoral heads were prepared by milling large particles in a bone mill and washing with AW-GC particles used as allografts. The bone grafting was performed according to the method described by Kim et al [3]. The morselized bone was packed into the bone defect as much as possible. Furthermore, the cortical autograft was held to the bone defect by steel wires, and the gap between the bone defect and cortical autograft was filled with the morselized cancellous autografts and allografts. Postoperatively, partial weight-bearing was encouraged for 3 months and then more weight-bearing with crutch walking was recommended for the following 3 months. Full weight-bearing was permitted 6 months after surgery. Clinical assessment was performed by two of the authors who were not the operating surgeon and who had over 20 years of experience. Additionally, they were blinded to the radiographic result at the time of the evaluation. Clinical assessment of hip joint function was performed preoperatively and at the most recent follow-up using the Japanese Orthopaedic Association (JOA) hip score [4]. The JOA Hip Score is a 100-point scale that comprises the subcategories of pain (0–40 points), range of motion (ROM; 0–20 points), ability to walk (gait; 0–20 points), and activities of daily living (ADL; 0–20 points). The maximum total score for a normal hip is 100 points, and high scores indicate better function. Patients with a good result achieved a score of ≥ 70 points. The final follow-up and preoperative scores were compared. Patients were carefully monitored for development of complications including dislocation, infection, fracture, sciatic nerve palsy, and deep venous thrombosis. The most recent radiographs were reviewed and compared with the initial postoperative radiographs. Two experienced examiners who were not the operating surgeon and who were blinded to the patient characteristics reviewed all radiographs and made all radiographic observations. Standardized images of the hip with the femur in the anteroposterior and lateral planes were obtained with a standard tube to cassette distance of 115 cm. The degree of preoperative bone loss was recorded as described by Paprosky et al [5]. Radiographs were
assessed for loosening, stable fixation, or bone ingrowth around the prosthesis based on criteria described by Engh et al [6]. Radiolucencies along the metal-bone interface were documented based on a modification of the method described by Gruen et al [7]. Stress shielding was assessed on the basis of bone density according to the criteria described by Moreland and Moreno [8]. Briefly, minimal stress shielding was indicated by little or no change in cortical density. Moderate stress shielding was indicated by significant and obvious loss of cortical density and thickness, whereas severe stress shielding was indicated by major, striking, and an impressive degree of bone loss. Cortical hypertrophy and osteolytic changes in cancellous bone density were recorded. Subsidence was measured using the Callaghan et al technique [9]. A movement of 3 mm or more was evaluated as subsidence, or alternatively, subsidence was regarded as definitely having occurred if the interlocking screws had broken. The osteotomy site in patients who had a bone fracture before surgery was considered as having healed radiologically if callus was seen bridging the site in the anteroposterior and lateral planes according to Chen et al [10]. The degree of stem filling was determined by the method developed by Mertl et al [11]. Stem filling was described as the ratio of stem diameter to femoral canal diameter 2 cm below the lesser trochanter, and referred to as the metaphyseal filling index (MFI). The presence or absence of screw fracture was determined. Failures were defined as stem removal, stem revision, stem migration over 5 mm, or extended osteolysis. The data were stored until review by an independent blinded observer. Statistical analyses were conducted using the JMP 11 (SAS Institute Inc., Cary, NC, USA). The data were analyzed using the Wilcoxon rank sum test. The level of significance was set at P b 0.05. Survivorship was calculated using the Kaplan–Meier analysis, with removal of the component for any reason as the criterion for failure. Survivorship data and 95% confidence intervals (CI) are presented with P b 0.05 considered as being significant.
Results Of the 40 consecutive patients (41 hips) enrolled, 2 were lost to follow-up, and 18 died of causes unrelated to the surgery. The remaining 20 patients (21 hips) were included in the study. A telephone interview with a standardized questionnaire, including the JOA score items, was conducted for 2 patients as they did not have a yearly follow-up visit and were not willing to come to the institution personally. Radiographic analysis could not be performed in these patients. The study participants included 6 men and 14 men (mean age at surgery, 62 years [range, 26–74]) with a mean follow-up duration of 15 years (range, 12–20). The diagnosis at the time of the primary hip replacement in these patients was developmental dysplasia of the hip in 14 patients (15 hips), fracture in 4 patients (4 hips), and femoral head necrosis in 2 patients (2 hips). Nineteen patients (20 hips) had undergone only 1 hip arthroplasty in the same hip before the revision and 1 patient (1 hip) had undergone 2 previous arthroplasties. The indication for the index revision was aseptic loosening of the cemented total hip arthroplasty in 11 hips (both components in 10 hips and only femoral component in 1 hip), failed hemi-replacement arthroplasty in 7 hips (aseptic loosening of the stem with migration), infected cemented bipolar prosthesis in 1 hip, and peri-prosthetic and prosthetic fracture in 2 hips. The length of the HUCKSTEP HIP stems used in the present study was 160 mm in 3 hips, 210 mm in 3 hips, and 260 mm in 15 hips. Both the femoral and the acetabular components were revised in 20 hips, and only the femoral component was revised in 1 hip. Exposure was achieved using a transfemoral osteotomy in 3 hips and a posterolateral approach in the remaining 18 hips. A transverse osteotomy for the correction of angular deformity in the diaphysis was performed in 4 hips. The bone defects in the medullary cavity were grafted with autologous bone chips and artificial bone granules in 11 hips, with allograft and artificial bone granules in 8 hips, and with only artificial bone in 2 hips (Fig. 2).
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
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The JOA hip score improved from 54 points (range, 15–73) preoperatively to 75 points (range, 47–82) at the final follow up, thereby showing a significant improvement (P b 0.05). This was considered a good clinical result, with a JOA score of ≥70 points. Postoperative dislocation occurred in 2 hips, both of which were reduced non-invasively. Postoperative infection occurred in 1 patient. Intraoperative fractures occurred in 4 hips (19%). Minor cracks were noted in the calcar region of 3 hips, and 1 crack was noted in the diaphyseal area. We used steel wires to secure the cracks, and all cracks healed without any complications. In one (33%) of the patients treated using the transfemoral approach, synostosis failure of the greater trochanter occurred, and invasive reduction was performed. One patient sustained a periprosthetic fracture distal to the tip of the prosthesis without loosening (Vancouver type-B fracture) 8 years after the surgery. This patient was successfully treated with open reduction internal fixation by plate osteosynthesis. None of the patients had sciatic nerve injury and deep venous thrombosis. Among the 21 hips, 8 were categorized as Paprosky type II deficiencies, 7 as type IIIA, 4 as type IIIB, and 2 as type IV. According to the Engh et al [6] classification concerning the biologic stem fixation, stable fixation was observed in 20 hips, and unstable fixation was observed in 1 hip with stem loosening. Nine hips presented with a radiolucent line in the distal stem section. Moderate stress shielding in the proximal section was noted in 15 hips. Cortical hypertrophy was observed around the distal screws in 11 hips. None of the hips demonstrated osteolysis. Subsidence occurred in 1 hip. In all of the 4 hips that underwent femoral osteotomy at the time of stem insertion and in the 2 hips in which a bone fracture had occurred before surgery, synostosis was achieved within 1 year after surgery. The mean MFI was 67% (range, 51–80%). Fracture of screw occurred in 2 hips (9.5%). In one of these, 1 screw broke 7 years after surgery. However, the screw fracture did not cause any symptoms, and no treatment was required. In the other hip, 4 screws broke 5 years after surgery leading to loosening and stem removal. No association was observed between MFI and stem failure. Stem failure was observed in 2 hips in which the stem was revised secondary to infection and removed due to subsidence. One of these patients was a 43-year-old man with a 14-year history of hemodialysis (Fig. 3A–D). He underwent femoral head arthroplasty with cement for
Fig. 2. The radiographs illustrate the case of a 50-year-old woman with revision of a loose stem and cup after 14 years. (A) The preoperative radiograph shows the loose acetabular cup and stems with a proximal bone defect type Paprosky IIIA. (B) The radiograph shows the hip 3 weeks after revision with implantation of a cementless press-fit cup and a HUCKSTEP hip stem with distal locking screws implanted by a posterior approach. (C) The radiograph shows the hip 20 years after surgery. The revision stem is unchanged and the interlocking screws are still intact. The proximal femoral bone shows mild stress shielding and cortical hypertrophy was observed around the distal screws.
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femoral head necrosis. Five years later, loosening occurred, and revision was performed with this stem. Five years after the revision, the screws broke followed by stem migration. Thus, the stem was removed. In the second case, this stem was removed because infection occurred 6 years after surgery. A sufficient amount of bone regeneration had occurred so that the stem could be exchanged for a shorter stem. The Kaplan–Meier stem survival rate was 90.4% (95% CI: 68.8%– 97.6%) at 15 years with femoral component revision for any reason as the end point (Fig. 4), and 90.2% (95% CI: 68.1%–97.5%) at 15 years with stem loosening and screw breakage as the end point (Fig. 5). Discussion The mid- to long-term clinical and radiographic outcomes of interlocking femoral stem use were found to be excellent. Favorable long-term outcomes were also achieved by these stems in cases classified as IIIB or IV according to the Paprosky classification. Proximal femoral bone defects are frequently present in those requiring hip replacement revisions due to stem loosening or a prosthetic fracture. The stem revision methods applied in cases of extensive bone defects or deficient isthmus include cemented revisions of femoral components [12], use of an extensively porous-coated stem, impaction allografting with long cementless stems, total femur arthroplasty, and use of a distal interlocking stem. However, Schmale et al [13] report that the results of the cemented revision of femoral components were unpredictable and that the intermediate results were discouraging. Distally fixed, extensively porous-coated stems are reported to be associated with high failure rates [14,15]. Cameron et al [16] report that primary fixation is difficult to achieve in cases of severe bone defects, which provide a poor biological and mechanical environment for proximal porous ingrowth. Furthermore, Harris et al [17] have provided the following description: “High stresses at the termination of the porous coating, where the dense cortical bone ingrowth occurs, with the resultant cantilever forces could lead to stem fracture, periprosthetic fracture, thigh pain, and late component loosening due to debonding and extrusion of the porous coating. Furthermore, proximal bone loss owing to stress shielding can predispose the patient to proximal periprosthetic fractures and also complicate further revision.” In addition, previous studies have reported the results of revision hip arthroplasty using the Wagner stem. Regis et al [18] reported a high rate of complications including subsidence and dislocation (significant subsidence was observed in ≥10% of the hips). They considered the inadequate offset of the Wagner SL design to be primarily responsible for this problem. Moreover, Pekkarinen et al [19] describe that impaction bone grafting is more likely to cause bone fractures in patients with bone defects or thin cortical bone. While total femur arthroplasty is a complicated surgical procedure, it is also reported to be associated with high infection rates and to cause functional limitations after surgery [20,21]. In order to achieve fixation with a cementless stem even in those with bone defects, a stem with distal interlocking screws is used [12,22–26]. This interlocking femoral stem used in the present study is derived from the titanium intramedullary nail fixation designed for the treatment of femoral comminuted fractures by Huckstep et al in 1967 [1,2]. This stem went out of production in 2010. This system is composed of a straight long stem with circumferential porous coating at the proximal section and interlocking screws at the proximal and distal sections. The interlocking screws were useful in providing early rotational and axial stability, and the calcar replacing prosthesis obviated the need for allograft reconstruction in hips with deficient calcar. In addition, the interlocking screws increase fixation stability of the porous implant, which may help to prevent implant loosening and subsequent periprosthetic fracture and subsidence. In our study subjects, no spot welds were observed around the proximal part of the porous surface and the stems were fibrous stable; however, no periprosthetic fracture or subsidence resulting from loosening occurred in any patient. Although all the stems had a diameter of 12.5 mm and thin cortical bone was observed, none of the
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
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T. Kamada et al. / The Journal of Arthroplasty xxx (2015) xxx–xxx
Fig. 3. The radiographs illustrate the case of a 43-year-old man on hemodialysis with revision of a cemented hip prosthesis. (A) The preoperative radiograph shows the loose acetabular cup and radiolucent around the cement at the proximal femur with a bone defect type Paprosky II. (B) The radiograph shows the hip 4 weeks after revision total hip arthroplasty. Six distal interlocking screws were inserted to provide additional stability. (C) The radiograph taken 5 years after surgery shows breakage of the interlocking screws because stem fixation only depended on the interlocking screws. (D) Photograph of removal screws. All screws had broken.
Fig. 4. Kaplan–Meier survival curve for all patients with failure for any reason as the end-point.
patients experienced a fracture. Mahomed et al [22] reported that distal interlocking increased the torsional stability by 320% and axial stability by 230%. In addition, compared to an extensively porous-coated stem, it is also easier to remove and causes fewer new bone defects. Meanwhile, there is a concern that because the load is mainly transmitted by distal screws, stress shielding may occur in the proximal cortical bone. Fink
Fig. 5. Kaplan–Meier survival curve for all patients with failure for aseptic loosening and screw fracture as the end-point.
et al [27] have reported that the use of long distally fixed stems in osteoporotic bones resulted in a stress-shielding effect, which can be regarded as a disadvantage. Paprosky et al [28] reported that proximal stress shielding is a lesser concern in revision surgery because predictable biologic fixation and longevity of implant survival take precedence over the stress shielding of an already deficient proximal femoral bone; the clinical significance of stress shielding should also be considered in revision surgery using the distal fixation method. In the present study, mild stress shielding was found in 10 hips (47%), whereas severe stress shielding of the proximal femur was not seen in any of the hips during the minimum follow-up period of 12 years. Only the interlocking femoral stem with a diameter of 12.5-mm was used. We consider the absence of severe stress shielding, even in the long-term follow-up, to be attributable to the thinner stem being thinner than the medullary cavity. Moreover, it is also reported that when a distal locking stem is used, insufficient bone ingrowth at the proximal section causes stress on distal screws, which in turn may break. Sotereanos et al [23] reported a single instance of stem subsidence and loosening in which the stem was too thin for adequate bony contact and fixation to occur. The interlocking screws also broke at more or less the same time after surgery because they were the sole source of fixation and stability in the revised prosthesis. Furthermore, Learmonth [24], who performed stem revision using interlocking screws for periprosthetic fractures of Vancouver type B2, reported breaking of the interlocking screws, resulting in subsidence of 5 mm or more in 5 out of 22 hips. The reported reason for this was that the chosen stem was too thin in the distal region. However, we assume that the model used by Learmonth, which uses 2 distal screws, is inferior in the strength of distal fixation to this interlocking femoral stem. Mertl et al [11] report that an MFI of 75% or below is associated with a 10-fold increased risk of screw fractures and subsidence. In the present study, the mean MFI was 67%, and MFI in patients with stem loosening was lower at 51%. However, no association was observed between screw fractures and MFI. The patient with stem migration was receiving dialysis and oral steroid therapy. Previous studies that examined the results of total hip arthroplasty in hemodialysis patients have reported early loosening. Naito et al [29] reported a loosening rate of 35% at 5 years and attributed this high failure rate to poor bone quality caused by renal osteodystrophy. Moreover, Toomey and Toomey [30] noted that loosening had occurred in 58% of cemented stems in a long-term follow-up study. In a patient with stem migration in the present study, we assume that although the bone prosthesis was implanted in the bone defects in the medullary cavity,
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
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bone ingrowth did not occur in the porous-coated section due to abnormal bone metabolism and amyloid deposition caused by long-term hemodialysis resulting in stem migration. In this series, cortical hypertrophy around the distal interlocking screws was seen in 16 hips (76%). Spot welds in the proximal porouscoated section were not confirmed in any of the patients, and stable fibrous fixation was achieved in all patients. Although screws provide stable fixation, there was no proximal osseointegration. Therefore, no bone ingrowth was observed, and this increased the risk of screw breakage in the future. Because this imposes a load on the distal screw section for a long period of time, we consider that distal screws should be inserted wherever possible. Furthermore, we did not remove the screws and left them in the implants during the follow-up period. We also consider that bone graft in the medullary cavity contributed to the achievement of stable fibrous fixation. In recent years, newer interlocking femoral stems have been developed; the first one was with HA coating on the proximal porous surface for successful bone ingrowth, the second with a larger porous surface area, and the third with a variation in stem size for reducing the load placed on the screws [10]. Our cumulative survival rate for this implant at 15 years is comparable with that of other revision stems used in similar situations [25,31]. Sexton et al [25] have reported cumulative survival rates of distal interlocking straight stems with 6–13 screw holes at the distal section (Kent) as 93% at 5 years, 89% at 10 years, and 77% at 15 years. In our study, the cumulative survival rate at 15 years was 90.4%, which was comparable to the above, and this also compares favorably with many of the other prostheses used in this type of a patient [32,33]. We recognize the limitations of our study, which include its retrospective nature, the small number of patients, and the lack of a control group undergoing an alternative treatment. Nevertheless, the use of a distal interlocking stem, even in cases of extensive femoral bone defects, facilitated salvage and achieved stable long-term outcomes. Although there is a risk of screw fractures or subsidence in cases without biologic osteointegration, we consider this interlocking femoral stem to play a critical role in the treatment of cases with extensive proximal bone defects, which render stem fixation difficult and in the treatment of those with a periprosthetic fracture. References 1. Huckstep RL. The Huckstep intramedullary compression nail. Indications, technique, and results. Clin Orthop Relat Res 1986;212:48. 2. Huckstep RL. Stabilization and prosthetic replacement in difficult fractures and bone tumors. Clin Orthop Relat Res 1987;224:12. 3. Kim YM, Kim HJ, Song WS, et al. Experiences with the BiCONTACT revision stems with distal interlocking. J Arthroplasty 2004;19:27. 4. Hasegawa Y, Iwata H, Mizuno M, et al. The natural course of osteoarthritis of the hip due to subluxation or acetabular dysplasia. Arch Orthop Trauma Surg 1992;111:187.
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5. Paprosky WG, Burnett RS. Assessment and classification of bone stock deficiency in revision total hip arthroplasty. Am J Orthop 2002;31:459. 6. Engh CA, Massin P, Suthers KE. Roentgenographic assessment of the biologic fixation of porous-surfaced femoral components. Clin Orthop Relat Res 1990;257:107. 7. Gruen TA, McNeice GM, Amstutz HC. “Modes of failure” of cemented stem-type femoral components: a radiographic analysis of loosening. Clin Orthop Relat Res 1979;141:17. 8. Moreland JR, Moreno MA. Cementless femoral revision arthroplasty of the hip: minimum 5 years follow up. Clin Orthop Relat Res 2001;393:194. 9. Callaghan JJ, Salvati EA, Pellicci PM, et al. Results of revision for mechanical failure after cemented total hip replacement, 1979 to 1982. A two to five-year follow-up. J Bone Joint Surg Am 1985;67:1074. 10. Chen WM, McAuley JP, Engh Jr CA, et al. Extended slide trochanteric osteotomy for revision total hip arthroplasty. J Bone Joint Surg Am 2000;82:1215. 11. Mertl P, Philippot R, Rosset P, et al. Distal locking stem for revision femoral loosening and periprosthetic fractures. Int Orthop 2011;35:275. 12. Eisler T, Svensson O, Iyer V, et al. Revision total hip arthroplasty using third generation cementing technique. J Arthroplasty 2000;15:974. 13. Schmale GA, Lachiewicz PF, Kelley SS. Early failure of revision total hip arthroplasty with cemented precoated femoral components: comparison with uncemented components at 2 to 8 years. J Arthroplasty 2000;15:718. 14. Weeden SH, Paprosky WG. Minimal 11-year follow-up of extensively porous-coated stems in femoral revision total hip arthroplasty. J Arthroplasty 2002;17:134. 15. Hamilton WG, Cashen DV, Ho H, et al. Extensively porous-coated stems for femoral revision. A choice for all seasons. J Arthroplasty 2007;22:106. 16. Cameron HU. The long-term success of modular proximal fixation stems in revision total hip arthroplasty. J Arthroplasty 2002;17:138. 17. Harris WH. Will stress shielding limit the longevity of cemented femoral components of total hip replacement? Clin Orthop Relat Res 1992;274:120. 18. Regis D, Sandri A, Bonetti I, et al. Femoral revision with the Wagner tapered stem. A ten- to 15-year follow-up study. J Bone Joint Surg (Br) 2011;93-B:1320. 19. Pekkarinen J, Alho A, Lepisto J, et al. Impaction bone grafting in revision hip surgery: a high incidence of complications. J Bone Joint Surg (Br) 2000;82:103. 20. Friesecke C, Plutat J, Block A. Revision arthroplasty with use of a total femur prosthesis. J Bone Joint Surg Am 2005;87:2693. 21. Parvizi J, Sim FH. Proximal femoral replacement with megaprostheses. Clin Orthop Relat Res 2004;420:169. 22. Mahomed N, Schatzker J, Hearn T. Biomechanical analysis of a distally interlocked press-fit femoral total hip prosthesis. J Arthroplasty 1993;8:129. 23. Sotereanos N, Sewecke J, Raukar GJ, et al. Revision total hip arthroplasty with a custom cementless stem with distal cross-locking screws. Early results in femora with large proximal segmental deficiencies. J Bone Joint Surg Am 2006;88:1079. 24. Learmonth ID. The management of periprosthetic fractures around the femoral stem. J Bone Joint Surg (Br) 2004;86:13. 25. Sexton SA, Stossel CA, Haddad FS. The Kent hip prosthesis: an evaluation of 145 prostheses after a mean of 5.1 years. J Bone Joint Surg (Br) 2006;88-B:310. 26. Bernd F, Grossmann A, Fuerst M. Distal interlocking screws with a modular revision stem for revision total hip arthroplasty in severe bone defects. J Arthroplasty 2010;25:759. 27. Fink B, Grossmann A. Modified transfemoral approach to revision arthroplasty with uncemented modular revision stems. Oper Orthop Traumatol 2007;19:32. 28. Paprosky WG, Greidanus NV, Antoniou J. Minimum 10-year-results of extensively porous-coated stems in revision hip arthroplasty. Clin Orthop Relat Res 1999;369:230. 29. Naito M, Ogata K, Shiota E, et al. Hip arthroplasty in haemodialysis patients. J Bone Joint Surg (Br) 1994;76:428. 30. Toomey HE, Toomey SD. Hip arthroplasty in chronic dialysis patients. J Arthroplasty 1998;13:647. 31. Volkmann R, Bretschneider C, Eingartner C, et al. Revision arthroplasty–femoral aspect: the concept to solve high grade defects. Int Orthop 2003;27(Suppl. 1):24. 32. Chandler H, Clark J, Murphy S, et al. Reconstruction of major segmental loss of the proximal femur in revision total hip arthroplasty. Clin Orthop Relat Res 1994;298:67. 33. Maron MC. Treatment of periprosthetic fractures around total hip arthroplasty with an extensively coated femoral component. J Arthroplasty 1996;11:981.
Please cite this article as: Kamada T, et al, Long Term Results With the Interlocking Uncemented Long Stem in Revision Hip Arthroplasty: A Mean 15-Year Follow-Up, J Arthroplasty (2015), http://dx.doi.org/10.1016/j.arth.2014.12.023
