International Orthopaedics (SICOT) (2015) 39:1839–1844 DOI 10.1007/s00264-015-2857-9
ORIGINAL PAPER
The value of bulk femoral head allograft in acetabular reconstruction using Kerboull-type plate Daisuke Inoue 1 & Tamon Kabata 1 & Toru Maeda 1 & Yoshitomo Kajino 1 & Takashi Yamamoto 1 & Tomoharu Takagi 1 & Takaaki Oomori 1 & Hiroyuki Tsuchiya 1
Received: 15 April 2015 / Accepted: 21 April 2015 / Published online: 12 July 2015 # SICOT aisbl 2015
Abstract Purpose This study investigated the mid- and long-term results of acetabular reconstruction using a KT plate with an allograft and showed the utility of filling the bony defect with bulk femoral head allograft rather than morselised allograft. Methods We retrospectively investigated a consecutive series of 31 hips in 30 patients who underwent primary THA or revision THA between March 2002 and March 2012. Bulk grafts from femoral head allografts were used in 16 hips and morselised grafts were used in 15 hips. The mean follow-up period was 7.2 years (3–13 years). The acetabular bone defects were classified according to the American Academy of Orthopedic Surgeons grading system. Type II defects were present in five hips; 26 hips were type III. Results Radiological failure, defined as absolute error of the inclination of the KT plate >3°, breakage of the KT plate or screw, and/or absolute error of the vertical or horizontal migration of the femoral head >3 mm was found in 12 cases. All these complications appeared in the morselized group; there were no complications in the bulk group. The eight-year survival rate of morselised grafts was 52.5 % and that of bulk grafts was 100 %, using radiological loosening as an end point. Conclusions We conclude that using bulk graft from femoral head allografts is necessary to achieve mechanically stable reconstruction for large acetabular bone defects.
* Tamon Kabata [email protected] 1
Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
Keywords Total hip arthroplasty . Acetabular reconstruction . Kerboull-type plate . Bulk allograft
Introduction In recent years, a growing number of more active patients has been undergoing total hip arthroplasty (THA). However, with these growing numbers, the number of revision THAs also is rapidly increasing. In revision THA, advanced surgical techniques are necessary to deal with extensive bone defects [1]. In such cases it is desirable that the component be placed at the primary acetabular position to maintain hip joint function, and it is necessary to appropriately augment the bone defect to achieve mechanical stability. In these situations we have used KT plates (Kyocera Medical, Osaka, Japan), which are modified Kerboull-type plates, and reconstructed large acetabular bone defects by using KT plates and allografts [2]. Several reports have showed good results for acetabular reconstruction using Kerboull-type plates with allografts, impaction bone grafting, jumbo cementless acetabular cups, and metal augments [3–6]. Compared to a Kerboull plate, the KT plate has many variations in the femoral head centre and offset, making it possible to anatomically reconstruct various types of bone defects. For bone grafting, we previously filled bony defects with morselised allograft in expectation of fast graft remodeling. However, a past report showed the collapse of grafted allograft and breakage of the KT plate when the defect was filled with morselised allograft [3]. Therefore, since 2007 we have filled bony defects with bulk femoral head allografts as much as possible to achieve a more mechanically stable reconstruction. This study investigated the mid- and long-term results of acetabular reconstruction using a KT plate with an allograft
1840
International Orthopaedics (SICOT) (2015) 39:1839–1844
and showed the utility of filling the bony defect with bulk femoral head allograft rather than morselised allograft.
Materials and methods We retrospectively investigated a consecutive series of 31 hips in 30 patients (6 men and 24 women) who underwent primary THA or revision THA between March 2002 and March 2012 using KT plates with allografts. The cases in this study had a minimum follow-up period of three years and all patients provided informed consent in accordance with the requirements of this review. The mean age of the patients was 58.1 ± 7.7 years (37–72 years). Patients were followed up for a mean of 7.2 years (3–13 years). The pre-operative diagnoses were secondary osteoarthritis due to developmental dysplasia of the hip (six hips), aseptic loosening (16 hips), central migration after hemiarthroplasty (two hips), septic loosening (two hips), rheumatoid arthritis (one hip), rapidly destructive coxoarthropathy (one hip), and reconstruction after tumour excision (three hips). The acetabular bone defects were classified according to the American Academy of Orthopedic Surgeons grading system. Type II defects were present in five hips; 26 hips were type III [7]. Bone grafting was performed using femoral head allografts. We did not use autogenous bone or artificial bone. Bulk grafts from the femoral head allografts were used in 16 hips (B group) and morselized grafts were used in 15 hips (M group). Femoral head allografts from patients who underwent primary THA for osteoarthritis of the hip joint were sterilized at −80 °C. Before the operation, the allograft was heated at 60 °C for eight hours. After removing the soft tissue and reaming the cartilage with a Noviomagus femoral head reamer (Matsumoto Amplitude, Tokyo, Japan), the femoral head allograft was used in the operation. Morselized allograft was fashioned from femoral head allografts using a bone mill. Bulk graft without large bone cysts was used for the femoral head allograft itself. Before 2007, we filled bone defects with morselised graft in all cases. After 2007, however, we used bulk femoral head allografts regardless of the type of bone defect because there were many cases of KT plate breakage when using morselized allografts (Fig. 1). Operative procedure All operations were performed by the senior surgeon (TK), using a posterolateral approach. The acetabular implant was removed and the underlying scar tissue was cleaned. Using the pre-operatively planned trial implant of the KT plate, the hook of the KT plate was placed under the obturator foramen and we checked the contact between the flange of the KT plate and the host bone. Then, the extent of the large bone defect was checked and the defect was filled with either a morselised or
Fig. 1 Step 1: Loosening the implant. Step 2: Using a bulk graft which does not have large bone cysts to achieve a mechanically stable reconstruction. Step 3: Filling the bone defect as much as possible with bulk allograft
femoral head allograft. The following three points were checked in intra-operative hip anteroposterior X-rays:(1) bone defects were filled with bone graft, (2) the hook of the KT plate was placed under the obturator foramen, (3) the location of the femoral head centre or femoral offset was appropriate. If there were no problems with the location of the KT plate or the volume of bone grafting, the KT plate was inserted to the acetabulum, and at least two screws were used to fix the plate to the host bone. Finally, the polyethylene cup was cemented onto the KT plate. Assessment The post-operative rehabilitation schedule was free weight bearing six weeks after the operation, and full weight bearing 2.5 months post operation. Anteroposterior hip X-rays were taken after operation, at about two weeks, three months, and one year. Thereafter, Xrays were taken at one-year intervals. For clinical evaluation, hip function was evaluated by the Japanese Orthopaedic Association (JOA) hip scoring system [8]. The JOA hip score includes scores for pain (40 points), ROM (20 points), walking (20 points), and activities of daily living (20 points), with a maximum score of 100 points. The pre-operative and final follow-up JOA hip scores were compared. Clinical hip evaluation was performed by the senior surgeon (TK). A radiological evaluation of the following factors was performed: vertical and horizontal migration of the centre of the femoral head, the inclination angle of the KT plate, failure rate of the KT plate, and thickness of the bone graft. The evaluation was conducted following the procedures reported by Okano et al. [9]. Vertical migration of the centre of the femoral head was defined as the distance between the interteardrop reference line and centre of the femoral head, and horizontal migration was defined as the distance between a perpendicular reference line drawn through the teardrop and centre of the
International Orthopaedics (SICOT) (2015) 39:1839–1844
femoral head (Fig. 2a, b). The inclination angle of the KT plate was defined as the angle between the interteardrop reference line and the line connecting the lower flange of the KT plate and its hook (Fig. 2c). Thickness of the bone graft was defined as the distance between the top of the margin of the bone graft and the top of the ring (Fig. 2d). As described in previous reports, radiological failure was defined as: (1) absolute error of the inclination of the KT plate >3°, (2) breakage of the KT plate or screw, (3) absolute error of the vertical or horizontal migration of the femoral head >3 mm. All radiological evaluations were performed by the first author (DI). The Kaplan-Meier method was used to conduct survival analysis, to estimate the cumulative probabilities of failure. The end point was defined as radiological failure of the KT plate.
Statistical analysis Statistical analysis was performed using SPSS software (PASW Statistics Base version 19; SPSS, Chicago, Illinois). The values of the JOA hip score, vertical and horizontal migration of the centre of the femoral head, the inclination angle of the KT-plate, and thickness of the bone graft were expressed as mean±standard deviation. A Student’ s T test was used to assess the difference between the morselised Fig. 2 a Vertical migration of the centre of the femoral head. b Horizontal migration of the centre of the femoral head. c Inclination angle of the KT-plate. d Thickness of the bone graft
1841
and bulk groups. A p-value < 0.05 was considered statistically significant.
Results Clinical evaluation The JOA hip score at the last follow up increased from a mean pre-operative score of 43.6±9.7 to a mean post-operative score of 79.9±16.8 points. Thus there was a significant improvement between pre-operative and post-operative JOA hip scores (P=0.01). Radiological evaluation The results of the radiological evaluation are shown in Table 1. There was no significant difference for the horizontal direction and abduction angle of the KT plate in either group. However, both groups showed significant differences in the vertical direction of the femoral head and thickness of the bone graft (P3° and
International Orthopaedics (SICOT) (2015) 39:1839–1844
1842 Table 1
Results of radiological analysis
Parameters
Morselised (n=15) Post op
Bulk (n=16) Final
P value
Post op
Final
P value
Horizontal centre of femoral head (mm)
32.7±5.0
30.3±10.4
0.39
31.3±3.8
31.7±3.5
0.79
Vertical centre of femoral head (mm) Inclination angle (angle) Thickness of the bone graft (mm)
25.1±9.0 43.0±8.0 20.8±7.4
34.0±14.0 53.3±29.8 12.6±7.0
ORIGINAL PAPER
The value of bulk femoral head allograft in acetabular reconstruction using Kerboull-type plate Daisuke Inoue 1 & Tamon Kabata 1 & Toru Maeda 1 & Yoshitomo Kajino 1 & Takashi Yamamoto 1 & Tomoharu Takagi 1 & Takaaki Oomori 1 & Hiroyuki Tsuchiya 1
Received: 15 April 2015 / Accepted: 21 April 2015 / Published online: 12 July 2015 # SICOT aisbl 2015
Abstract Purpose This study investigated the mid- and long-term results of acetabular reconstruction using a KT plate with an allograft and showed the utility of filling the bony defect with bulk femoral head allograft rather than morselised allograft. Methods We retrospectively investigated a consecutive series of 31 hips in 30 patients who underwent primary THA or revision THA between March 2002 and March 2012. Bulk grafts from femoral head allografts were used in 16 hips and morselised grafts were used in 15 hips. The mean follow-up period was 7.2 years (3–13 years). The acetabular bone defects were classified according to the American Academy of Orthopedic Surgeons grading system. Type II defects were present in five hips; 26 hips were type III. Results Radiological failure, defined as absolute error of the inclination of the KT plate >3°, breakage of the KT plate or screw, and/or absolute error of the vertical or horizontal migration of the femoral head >3 mm was found in 12 cases. All these complications appeared in the morselized group; there were no complications in the bulk group. The eight-year survival rate of morselised grafts was 52.5 % and that of bulk grafts was 100 %, using radiological loosening as an end point. Conclusions We conclude that using bulk graft from femoral head allografts is necessary to achieve mechanically stable reconstruction for large acetabular bone defects.
* Tamon Kabata [email protected] 1
Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
Keywords Total hip arthroplasty . Acetabular reconstruction . Kerboull-type plate . Bulk allograft
Introduction In recent years, a growing number of more active patients has been undergoing total hip arthroplasty (THA). However, with these growing numbers, the number of revision THAs also is rapidly increasing. In revision THA, advanced surgical techniques are necessary to deal with extensive bone defects [1]. In such cases it is desirable that the component be placed at the primary acetabular position to maintain hip joint function, and it is necessary to appropriately augment the bone defect to achieve mechanical stability. In these situations we have used KT plates (Kyocera Medical, Osaka, Japan), which are modified Kerboull-type plates, and reconstructed large acetabular bone defects by using KT plates and allografts [2]. Several reports have showed good results for acetabular reconstruction using Kerboull-type plates with allografts, impaction bone grafting, jumbo cementless acetabular cups, and metal augments [3–6]. Compared to a Kerboull plate, the KT plate has many variations in the femoral head centre and offset, making it possible to anatomically reconstruct various types of bone defects. For bone grafting, we previously filled bony defects with morselised allograft in expectation of fast graft remodeling. However, a past report showed the collapse of grafted allograft and breakage of the KT plate when the defect was filled with morselised allograft [3]. Therefore, since 2007 we have filled bony defects with bulk femoral head allografts as much as possible to achieve a more mechanically stable reconstruction. This study investigated the mid- and long-term results of acetabular reconstruction using a KT plate with an allograft
1840
International Orthopaedics (SICOT) (2015) 39:1839–1844
and showed the utility of filling the bony defect with bulk femoral head allograft rather than morselised allograft.
Materials and methods We retrospectively investigated a consecutive series of 31 hips in 30 patients (6 men and 24 women) who underwent primary THA or revision THA between March 2002 and March 2012 using KT plates with allografts. The cases in this study had a minimum follow-up period of three years and all patients provided informed consent in accordance with the requirements of this review. The mean age of the patients was 58.1 ± 7.7 years (37–72 years). Patients were followed up for a mean of 7.2 years (3–13 years). The pre-operative diagnoses were secondary osteoarthritis due to developmental dysplasia of the hip (six hips), aseptic loosening (16 hips), central migration after hemiarthroplasty (two hips), septic loosening (two hips), rheumatoid arthritis (one hip), rapidly destructive coxoarthropathy (one hip), and reconstruction after tumour excision (three hips). The acetabular bone defects were classified according to the American Academy of Orthopedic Surgeons grading system. Type II defects were present in five hips; 26 hips were type III [7]. Bone grafting was performed using femoral head allografts. We did not use autogenous bone or artificial bone. Bulk grafts from the femoral head allografts were used in 16 hips (B group) and morselized grafts were used in 15 hips (M group). Femoral head allografts from patients who underwent primary THA for osteoarthritis of the hip joint were sterilized at −80 °C. Before the operation, the allograft was heated at 60 °C for eight hours. After removing the soft tissue and reaming the cartilage with a Noviomagus femoral head reamer (Matsumoto Amplitude, Tokyo, Japan), the femoral head allograft was used in the operation. Morselized allograft was fashioned from femoral head allografts using a bone mill. Bulk graft without large bone cysts was used for the femoral head allograft itself. Before 2007, we filled bone defects with morselised graft in all cases. After 2007, however, we used bulk femoral head allografts regardless of the type of bone defect because there were many cases of KT plate breakage when using morselized allografts (Fig. 1). Operative procedure All operations were performed by the senior surgeon (TK), using a posterolateral approach. The acetabular implant was removed and the underlying scar tissue was cleaned. Using the pre-operatively planned trial implant of the KT plate, the hook of the KT plate was placed under the obturator foramen and we checked the contact between the flange of the KT plate and the host bone. Then, the extent of the large bone defect was checked and the defect was filled with either a morselised or
Fig. 1 Step 1: Loosening the implant. Step 2: Using a bulk graft which does not have large bone cysts to achieve a mechanically stable reconstruction. Step 3: Filling the bone defect as much as possible with bulk allograft
femoral head allograft. The following three points were checked in intra-operative hip anteroposterior X-rays:(1) bone defects were filled with bone graft, (2) the hook of the KT plate was placed under the obturator foramen, (3) the location of the femoral head centre or femoral offset was appropriate. If there were no problems with the location of the KT plate or the volume of bone grafting, the KT plate was inserted to the acetabulum, and at least two screws were used to fix the plate to the host bone. Finally, the polyethylene cup was cemented onto the KT plate. Assessment The post-operative rehabilitation schedule was free weight bearing six weeks after the operation, and full weight bearing 2.5 months post operation. Anteroposterior hip X-rays were taken after operation, at about two weeks, three months, and one year. Thereafter, Xrays were taken at one-year intervals. For clinical evaluation, hip function was evaluated by the Japanese Orthopaedic Association (JOA) hip scoring system [8]. The JOA hip score includes scores for pain (40 points), ROM (20 points), walking (20 points), and activities of daily living (20 points), with a maximum score of 100 points. The pre-operative and final follow-up JOA hip scores were compared. Clinical hip evaluation was performed by the senior surgeon (TK). A radiological evaluation of the following factors was performed: vertical and horizontal migration of the centre of the femoral head, the inclination angle of the KT plate, failure rate of the KT plate, and thickness of the bone graft. The evaluation was conducted following the procedures reported by Okano et al. [9]. Vertical migration of the centre of the femoral head was defined as the distance between the interteardrop reference line and centre of the femoral head, and horizontal migration was defined as the distance between a perpendicular reference line drawn through the teardrop and centre of the
International Orthopaedics (SICOT) (2015) 39:1839–1844
femoral head (Fig. 2a, b). The inclination angle of the KT plate was defined as the angle between the interteardrop reference line and the line connecting the lower flange of the KT plate and its hook (Fig. 2c). Thickness of the bone graft was defined as the distance between the top of the margin of the bone graft and the top of the ring (Fig. 2d). As described in previous reports, radiological failure was defined as: (1) absolute error of the inclination of the KT plate >3°, (2) breakage of the KT plate or screw, (3) absolute error of the vertical or horizontal migration of the femoral head >3 mm. All radiological evaluations were performed by the first author (DI). The Kaplan-Meier method was used to conduct survival analysis, to estimate the cumulative probabilities of failure. The end point was defined as radiological failure of the KT plate.
Statistical analysis Statistical analysis was performed using SPSS software (PASW Statistics Base version 19; SPSS, Chicago, Illinois). The values of the JOA hip score, vertical and horizontal migration of the centre of the femoral head, the inclination angle of the KT-plate, and thickness of the bone graft were expressed as mean±standard deviation. A Student’ s T test was used to assess the difference between the morselised Fig. 2 a Vertical migration of the centre of the femoral head. b Horizontal migration of the centre of the femoral head. c Inclination angle of the KT-plate. d Thickness of the bone graft
1841
and bulk groups. A p-value < 0.05 was considered statistically significant.
Results Clinical evaluation The JOA hip score at the last follow up increased from a mean pre-operative score of 43.6±9.7 to a mean post-operative score of 79.9±16.8 points. Thus there was a significant improvement between pre-operative and post-operative JOA hip scores (P=0.01). Radiological evaluation The results of the radiological evaluation are shown in Table 1. There was no significant difference for the horizontal direction and abduction angle of the KT plate in either group. However, both groups showed significant differences in the vertical direction of the femoral head and thickness of the bone graft (P3° and
International Orthopaedics (SICOT) (2015) 39:1839–1844
1842 Table 1
Results of radiological analysis
Parameters
Morselised (n=15) Post op
Bulk (n=16) Final
P value
Post op
Final
P value
Horizontal centre of femoral head (mm)
32.7±5.0
30.3±10.4
0.39
31.3±3.8
31.7±3.5
0.79
Vertical centre of femoral head (mm) Inclination angle (angle) Thickness of the bone graft (mm)
25.1±9.0 43.0±8.0 20.8±7.4
34.0±14.0 53.3±29.8 12.6±7.0
