DOI: 10.5301/hipint.5000133
Hip Int 2014; 24 ( 4): 399-404
ORIGINAL ARTICLE
Primary total hip arthroplasty (THA) in patients with incomplete hip abductor tears: does hip abductor repair improve outcome? Michael Betz1, Patrick O. Zingg1, Anna Hirschmann1, Amin Alireza2, Claudio Dora1 1 2
Balgrist University Hospital, Zurich - Switzerland Tehran University, Tehran - Iran
Introduction: Incomplete tears of the hip abductor insertion can coexist with primary hip osteoarthritis. The aim of this investigation was to test the hypotheses that: 1) the outcome of patients undergoing primary THA using a direct anterior approach would be inferior when hip abductor pathology was present; and 2) in the presence of incomplete tears, the transgluteal approach with hip abductor repair delivers a superior outcome compared to the direct anterior approach. Patients and Methods: Forty patients underwent MR imaging of the hip abductor insertion prior to THA. The grade of abductor tears was assessed, the approach used for THA was recorded, and pre- and postoperative one-year outcome scores (WOMAC, HHS) were recorded. Results: Twenty patients showed a normal appearance of the hip abductor insertion and THA was performed using the direct anterior approach (group 1). In 20 patients partial tears of the hip abductor insertion were recognized. Eight of them had THA through a direct anterior approach (group 2) and twelve through a transgluteal approach with repair (group 3). All patients improved after surgery. Overall the WOMAC improved from 6.1 to 2.1 points and the HHS from 46 to 87 points. A significantly higher benefit in terms of the HHS was achieved in patients of group 1 (p = 0.045). No significant differences were recorded between group 2 and group 3. Conclusions: Improvement in outcome scores after THA using the direct anterior approach was inferior in the presence of partial hip abductor tears. The repair of partial hip abductor tears was not associated with superior clinical results. Keywords: Hip abductor tears, THA, Repair, Anterior vs transgluteal approach, Clinical outcome Accepted: January 15, 2014
INTRODUCTION Incomplete tears of the hip abductor insertion were first described by Bunker and termed rotator cuff tears of the hip (1). They can coexist with primary hip osteoarthritis and are associated with trochanteric surface irregularities on anteroposterior hip radiographs (2). Magnetic resonance (MR) imaging is the diagnostic investigation of choice allowing detailed visualisation of the hip abductor tendon insertion and the presence of partial or complete tears (3).
Whereas the anterolateral (4), transgluteal (5) and posterior approach (6, 7) for THA can all expose such tears making repair during the same procedure possible, the direct anterior approach (8, 9) uses an interval between the tensor fascia latae and sartorius muscle without visualising the hip abdcutor insertion. Therefore the direct anterior approach is (in our opinion) not suitable for the repair of hip abductor tears. This might be a disadvantage of the direct anterior approach, which has gained wide popularity due to its internervous and intermuscular plane, which minimises
© 2014 Wichtig Publishing - ISSN 1120-7000
399
Abductor tears - Repair versus no repair
damage to hip muscles and tendons (10). On the other hand the impact of concomitant hip abductor tears on the outcome after THA remains unknown. Having adopted the minimally invasive direct anterior approach for primary THA in 2004, our awareness of concomitant incomplete tears of the hip abductor insertion was low, inconsistently recognised and inconsistently addressed. In order to find a more consistent attitude with respect to the most adequate approach for THA in the presence of incomplete tears of the hip abductor insertion we performed a retrospective investigation. The aim was to test the hypotheses that: 1) the outcome of patients undergoing primary THA using a minimally invasive direct anterior approach would be inferior when concomitant hip abductor pathology was present; and 2) in the presence of concomitant incomplete tears, the transgluteal approach with repair delivers superior outcomes to the direct anterior approach (ignoring tears).
PATIENTS AND METHODS Patients Our prospective database of primary total hip replacements was retrospectively reviewed for patients who underwent primary THA between 2005 and 2010 and had MR investigation of the hip abductor insertion prior to surgery. From 1342 patients undergoing primary THA during this time period, 61 had preoperative MR. Out of the latter, 40 patients presented with primary osteoarthritis. They underwent MR because of obvious hip abductor weakness and/or pertrochanteric pain leading to the suspicion of a hip abductor tear. These 40 patients represent the study group. The remaining 21 patients had preoperative MR because of other causes such as complex hip deformities following paediatric hip disease (eight patients), suspicion of iatrogenic hip abductor injuries following previous hip surgery (five patients), grading of femoral head necrosis (four patients), cartilage evaluation (two patients) and metastatic bone disease (two patients – excluded from the study).
Evaluation Age, gender and body mass index at time of surgery were recorded. The study group was retrospectively analysed 400
for the presence and grade of abductor tears on MR imaging, which all had been acquired and rated following a protocol described by Pfirrmann et al (3) using the same 1.5-T scanner (Magnetom Avanto and Magnetom Espree, Siemens Healthcare, Erlangen, Germany) with a body matrix phased-array coil. T1-weighted images were acquired in the axial (repetition time msec/echo time msec, 533/12; section thickness, 6 mm; field of view, 180 × 180 mm; matrix size, 512 × 512 mm; acquisition time, 2 mins 30 secs) and in the sagittal planes (471/12; section thickness, 4 mm; field of view, 200 x 200 mm; matrix size, 320 × 320 mm; acquisition time, 2 mins 43 secs). T2-weighted images were acquired in the coronal plane (3760/63; section thickness, 4 mm; field of view, 220 × 220 mm; matrix size, 512 × 512 mm; acquisition time, 3 mins 53 secs) as well as STIR images in the axial plane (4890/45; section thickness, 7 mm; field of view, 180 × 180 mm; matrix size, 512 × 512 mm; acquisition time, 2 mins 58 secs). The abductor tendons and muscles were divided into three parts: anterior, involving the tendon of gluteus minimus; lateral, involving the lateral part of gluteus medius; and posterior, involving the posterior part of the gluteus medius. Defects in the tendon such as tears or detachments, were identified as hyperintense signals extending to both surfaces of the tendon on fluidsensitive MR-sequences. The diameter of the tendon was evaluated qualitatively as normal or altered in the sense of a partial tear or a complete transmural tear. The grade of fatty infiltration was evaluated for the gluteus medius and gluteus minimus muscle on transverse T1-weighted MR scans at two different levels: at one-third and at two-thirds of the distance between the iliac crest and the tip of the greater trochanter (3); and graded according to Goutallier et al (11) (Grade 0 = no fatty deposits; Grade 1 = some fatty streaks; Grade 2 = muscle > fat; Grade 3 = muscle = fat; Grade 4 = muscle < fat). One experienced musculoskeletal radiologist performed this analysis and was blinded with regard to the surgical approach used. In Pfirrmann’s study interobserver agreement for assessment of abductor tendon defects was shown to be moderate to excellent (k, 0.577-0.862) (3). Lower aggreement was achieved for assessment of tendon diameter (k, 0.474-0.559) and signal intensity changes (k, 0.341-0.581) (3). Additionally, the approach used for THA, pre- and postoperative one-year outcome scores ((Western Ontario and McMaster University Osteoarthritis Index (WOMAC) (12), Harris Hip Score (HHS)) (13), Trendelenburg sign (yes/no), hip abductor strength (M0 to M5) according to the Medical
© 2014 Wichtig Publishing - ISSN 1120-7000
Betz et al
Research Council scale (14) and pertrochanteric tenderness (yes/no) were recorded from the database. The WOMAC consists of 24 items addressing the three dimensions: pain, stiffness and physical function. Items were scored with a rating system consisting of five grades (no = 0, mild = 2.5, moderate = 5, severe = 7.5, extreme = 10 points). The dimension scores were calculated as the mean of the items, with 10 representing worst pain, stiffness and physical function. Finally, possible implant loosening was assessed, and femoral offset and leg length discrepancy were measured on antero-posterior pelvic and cross table axial hip radiographs obtained one year postoperatively.
Surgical techniques The direct anterior approach was performed on an extension-distraction table (AMIS mobile leg positioner; Medacta, Castel San Pietro, Switzerland). The skin incision was centred on the tensor fascia lata and its fascial sheath entered before blunt dissection along its medial border was performed. A U-shaped capsulotomy was followed by the anchoring of a soft-tissue retractor within the joint capsule. After resection of the femoral head and implantation of the acetabular component the leg was secured in about 20° to 30° of extension, 90° of external rotation and 20° of adduction using the leg positioner for preparation of the femoral canal (10). The patients began to mobilise on two crutches on the day after surgery, bearing weight as tolerated, for two weeks. After this period walking without supports was allowed. The transgluteal approach was used according to the method of Bauer and Russe (5) with the patient in the lateral position. The hip abductor insertion site was roughened
leaving a bleeding bony surface and hip abductor refixation was performed using nonabsorbable transosseous sutures (Ethibond 3; Ethicon, Spreitenbach, Switzerland) tied using a modified Masson-Allen stitch (15, 16). To protect healing two crutches were used for six weeks with partial weight bearing.
Statistics The Fisher exact test was used for analysing categorical differences between the groups in terms of gender, presence of Trendelenburg sign and pertrochanteric tenderness, tendon defects and fatty infiltration. The nonparametric variables (WOMAC, HHS) preoperative to one-year follow-up were compared using the Wilcoxon sign rank test. The MannWhitney-U test was used for the comparison of continuous variables between groups of patients (age, BMI, WOMAC, HHS, hip abductor strength). All statistical analyses were performed using SPSS for Windows version 11.0 (SPSS Inc., Chicago, Illinois). A p-value ≤ 0.05 was deemed significant.
RESULTS From 40 patients with preoperative MR of the hip abductors, 20 patients showed a normal appearance of the hip abductor insertion and THA was performed using the direct anterior approach (group 1). In 20 patients partial to transmural tears of the anterolateral portion of the hip abductor insertion were recognised. Eight of them had THA through a direct anterior approach (group 2) and 12 through a transgluteal approach with repair (group 3). In terms of age, gender and body mass index no significant differences between the groups were found (Tab. I).
TABLE I - DEMOGRAPHIC DATA ON THE PATIENTS Group 1
Number of hips (n) Age
Group 2
Group 3
20
8
12
67 ± 12
73 ± 7
74 ± 7
18/2
8/0
11/1
25 ± 4
27 ± 4
31 ± 6
Gender (female/male) BMI (kg/m2)
P value 1/2
1/3
2/3
*ns
*ns
*ns
†
ns
*ns
†
ns
*ns
†
ns
*ns
BMI = body mass index. *MannWhitney-U test, †Fisher exact test. © 2014 Wichtig Publishing - ISSN 1120-7000
401
Abductor tears - Repair versus no repair
All but one patient with degenerative hip abductor tears were female. Different combinations and severities of partial and transmural hip abductor tears are summarised in Table II. No statistically significant difference was found between groups 2 and 3. Significant differences in minor fatty infiltration were only found for the gluteus minimus muscle
TABLE II - PREOPERATIVE HIP ABDUCTOR TEARS IN GROUP 2 (ANTERIOR APPROACH) AND GROUP 3 (TRANSGLUTEAL APPROACH) Group 2
Group 3
Partial anterior
1
1
Partial lateral
2
Transmural lateral
1
Transmural anterior + partial lateral
2 1
Transmural lateral and partial anterior
1
Transmural anterior and lateral
3
P value
†
ns
8
Fisher exact test.
†
between groups 1 and 2, and groups 1 and 3 (Tab. III). No significant difference in fatty infiltration was found between groups 2 and 3 (Tab. III). In terms of preoperative scores, the HHS and WOMAC were not statistically different between the groups (Tab. IV). In terms of preoperative Trendelenburg sign, pertrochanteric tenderness and hip abductor strength, no differences were encountered (Tab. IV). The WOMAC and HHS significantly improved after surgery in all 3 groups (Tab. IV). Significant improvement was recorded for the Trendelenburg sign in groups 1 and 2, for pertrochanteric tenderness in group 1 and 3 and for hip abductor strength in group 1 (Tab. IV). Whereas no significant difference with respect to the WOMAC and HHS was found one year postoperatively between the three groups (Tab. IV), the gain in terms of the HHS was significantly higher in group 1 (p = 0.045). Additionally, significantly fewer patients showed a positive Trendelenburg sign and significantly higher abductor strength was encountered for group 1 when compared to group 3. On conventional radiographs no signs of prosthetic loosening were detected. There were no significant differences in terms of femoral offset and leg length between the groups.
TABLE III - PREOPERATIVE FATTY INFILTRATION OF HIP ABDUCTORS (GOUTALLIER GRADES) P value† Group 1 Gluteus minimus
Cranial iliac crest
Caudal iliac crest
Gluteus medius
Cranial iliac crest
Caudal iliac crest
Group 2
Group 3
1/2
1/3
2/3
Anterior
1.6
1.5
1.67
ns
ns
ns
Middle
1.1
2.25
1.83
0.03
ns
ns
Posterior
0.25
1.25
1.58
0.02
0.01
ns
Anterior
1.05
0.88
0.92
ns
ns
ns
Middle
1.15
2.75
2.0
0.002
ns
ns
Posterior
0.25
1.25
0.75
0.003
ns
ns
Anterior
0.6
0.38
1.17
ns
ns
ns
Middle
0.4
0.25
0.67
ns
ns
ns
Posterior
0.25
0
0
ns
ns
ns
Anterior
0.4
0.63
0.75
ns
ns
ns
Middle
0.4
0.38
1.25
ns
ns
ns
Posterior
0.15
0.25
0.08
ns
ns
ns
Fisher exact test.
†
402
© 2014 Wichtig Publishing - ISSN 1120-7000
Betz et al
TABLE IV - CLINICAL OUTCOME Group 1 Preop
Postop
Group 2 P value
Preop
Postop
Group 3 P value
Preop
Postop
P value P value
1/2
1/3
2/3
Pre- Post- Pre- Post- Pre- Postop op op op op op Total WOMAC ± SD
6.3 ± 1
1.6 ± 1.6
41 ± 19.4
91 ± 13
‡
Trendelenburg (yes)
15
2
†
Hip abductor strength (M0-M5) ± SD
4 ± 0.6
4.7 ± 0.5
†
16
5
†
HHS ± SD
Pertrochanteric tenderness (yes)
2.2 ± 2.0
‡
Hip Int 2014; 24 ( 4): 399-404
ORIGINAL ARTICLE
Primary total hip arthroplasty (THA) in patients with incomplete hip abductor tears: does hip abductor repair improve outcome? Michael Betz1, Patrick O. Zingg1, Anna Hirschmann1, Amin Alireza2, Claudio Dora1 1 2
Balgrist University Hospital, Zurich - Switzerland Tehran University, Tehran - Iran
Introduction: Incomplete tears of the hip abductor insertion can coexist with primary hip osteoarthritis. The aim of this investigation was to test the hypotheses that: 1) the outcome of patients undergoing primary THA using a direct anterior approach would be inferior when hip abductor pathology was present; and 2) in the presence of incomplete tears, the transgluteal approach with hip abductor repair delivers a superior outcome compared to the direct anterior approach. Patients and Methods: Forty patients underwent MR imaging of the hip abductor insertion prior to THA. The grade of abductor tears was assessed, the approach used for THA was recorded, and pre- and postoperative one-year outcome scores (WOMAC, HHS) were recorded. Results: Twenty patients showed a normal appearance of the hip abductor insertion and THA was performed using the direct anterior approach (group 1). In 20 patients partial tears of the hip abductor insertion were recognized. Eight of them had THA through a direct anterior approach (group 2) and twelve through a transgluteal approach with repair (group 3). All patients improved after surgery. Overall the WOMAC improved from 6.1 to 2.1 points and the HHS from 46 to 87 points. A significantly higher benefit in terms of the HHS was achieved in patients of group 1 (p = 0.045). No significant differences were recorded between group 2 and group 3. Conclusions: Improvement in outcome scores after THA using the direct anterior approach was inferior in the presence of partial hip abductor tears. The repair of partial hip abductor tears was not associated with superior clinical results. Keywords: Hip abductor tears, THA, Repair, Anterior vs transgluteal approach, Clinical outcome Accepted: January 15, 2014
INTRODUCTION Incomplete tears of the hip abductor insertion were first described by Bunker and termed rotator cuff tears of the hip (1). They can coexist with primary hip osteoarthritis and are associated with trochanteric surface irregularities on anteroposterior hip radiographs (2). Magnetic resonance (MR) imaging is the diagnostic investigation of choice allowing detailed visualisation of the hip abductor tendon insertion and the presence of partial or complete tears (3).
Whereas the anterolateral (4), transgluteal (5) and posterior approach (6, 7) for THA can all expose such tears making repair during the same procedure possible, the direct anterior approach (8, 9) uses an interval between the tensor fascia latae and sartorius muscle without visualising the hip abdcutor insertion. Therefore the direct anterior approach is (in our opinion) not suitable for the repair of hip abductor tears. This might be a disadvantage of the direct anterior approach, which has gained wide popularity due to its internervous and intermuscular plane, which minimises
© 2014 Wichtig Publishing - ISSN 1120-7000
399
Abductor tears - Repair versus no repair
damage to hip muscles and tendons (10). On the other hand the impact of concomitant hip abductor tears on the outcome after THA remains unknown. Having adopted the minimally invasive direct anterior approach for primary THA in 2004, our awareness of concomitant incomplete tears of the hip abductor insertion was low, inconsistently recognised and inconsistently addressed. In order to find a more consistent attitude with respect to the most adequate approach for THA in the presence of incomplete tears of the hip abductor insertion we performed a retrospective investigation. The aim was to test the hypotheses that: 1) the outcome of patients undergoing primary THA using a minimally invasive direct anterior approach would be inferior when concomitant hip abductor pathology was present; and 2) in the presence of concomitant incomplete tears, the transgluteal approach with repair delivers superior outcomes to the direct anterior approach (ignoring tears).
PATIENTS AND METHODS Patients Our prospective database of primary total hip replacements was retrospectively reviewed for patients who underwent primary THA between 2005 and 2010 and had MR investigation of the hip abductor insertion prior to surgery. From 1342 patients undergoing primary THA during this time period, 61 had preoperative MR. Out of the latter, 40 patients presented with primary osteoarthritis. They underwent MR because of obvious hip abductor weakness and/or pertrochanteric pain leading to the suspicion of a hip abductor tear. These 40 patients represent the study group. The remaining 21 patients had preoperative MR because of other causes such as complex hip deformities following paediatric hip disease (eight patients), suspicion of iatrogenic hip abductor injuries following previous hip surgery (five patients), grading of femoral head necrosis (four patients), cartilage evaluation (two patients) and metastatic bone disease (two patients – excluded from the study).
Evaluation Age, gender and body mass index at time of surgery were recorded. The study group was retrospectively analysed 400
for the presence and grade of abductor tears on MR imaging, which all had been acquired and rated following a protocol described by Pfirrmann et al (3) using the same 1.5-T scanner (Magnetom Avanto and Magnetom Espree, Siemens Healthcare, Erlangen, Germany) with a body matrix phased-array coil. T1-weighted images were acquired in the axial (repetition time msec/echo time msec, 533/12; section thickness, 6 mm; field of view, 180 × 180 mm; matrix size, 512 × 512 mm; acquisition time, 2 mins 30 secs) and in the sagittal planes (471/12; section thickness, 4 mm; field of view, 200 x 200 mm; matrix size, 320 × 320 mm; acquisition time, 2 mins 43 secs). T2-weighted images were acquired in the coronal plane (3760/63; section thickness, 4 mm; field of view, 220 × 220 mm; matrix size, 512 × 512 mm; acquisition time, 3 mins 53 secs) as well as STIR images in the axial plane (4890/45; section thickness, 7 mm; field of view, 180 × 180 mm; matrix size, 512 × 512 mm; acquisition time, 2 mins 58 secs). The abductor tendons and muscles were divided into three parts: anterior, involving the tendon of gluteus minimus; lateral, involving the lateral part of gluteus medius; and posterior, involving the posterior part of the gluteus medius. Defects in the tendon such as tears or detachments, were identified as hyperintense signals extending to both surfaces of the tendon on fluidsensitive MR-sequences. The diameter of the tendon was evaluated qualitatively as normal or altered in the sense of a partial tear or a complete transmural tear. The grade of fatty infiltration was evaluated for the gluteus medius and gluteus minimus muscle on transverse T1-weighted MR scans at two different levels: at one-third and at two-thirds of the distance between the iliac crest and the tip of the greater trochanter (3); and graded according to Goutallier et al (11) (Grade 0 = no fatty deposits; Grade 1 = some fatty streaks; Grade 2 = muscle > fat; Grade 3 = muscle = fat; Grade 4 = muscle < fat). One experienced musculoskeletal radiologist performed this analysis and was blinded with regard to the surgical approach used. In Pfirrmann’s study interobserver agreement for assessment of abductor tendon defects was shown to be moderate to excellent (k, 0.577-0.862) (3). Lower aggreement was achieved for assessment of tendon diameter (k, 0.474-0.559) and signal intensity changes (k, 0.341-0.581) (3). Additionally, the approach used for THA, pre- and postoperative one-year outcome scores ((Western Ontario and McMaster University Osteoarthritis Index (WOMAC) (12), Harris Hip Score (HHS)) (13), Trendelenburg sign (yes/no), hip abductor strength (M0 to M5) according to the Medical
© 2014 Wichtig Publishing - ISSN 1120-7000
Betz et al
Research Council scale (14) and pertrochanteric tenderness (yes/no) were recorded from the database. The WOMAC consists of 24 items addressing the three dimensions: pain, stiffness and physical function. Items were scored with a rating system consisting of five grades (no = 0, mild = 2.5, moderate = 5, severe = 7.5, extreme = 10 points). The dimension scores were calculated as the mean of the items, with 10 representing worst pain, stiffness and physical function. Finally, possible implant loosening was assessed, and femoral offset and leg length discrepancy were measured on antero-posterior pelvic and cross table axial hip radiographs obtained one year postoperatively.
Surgical techniques The direct anterior approach was performed on an extension-distraction table (AMIS mobile leg positioner; Medacta, Castel San Pietro, Switzerland). The skin incision was centred on the tensor fascia lata and its fascial sheath entered before blunt dissection along its medial border was performed. A U-shaped capsulotomy was followed by the anchoring of a soft-tissue retractor within the joint capsule. After resection of the femoral head and implantation of the acetabular component the leg was secured in about 20° to 30° of extension, 90° of external rotation and 20° of adduction using the leg positioner for preparation of the femoral canal (10). The patients began to mobilise on two crutches on the day after surgery, bearing weight as tolerated, for two weeks. After this period walking without supports was allowed. The transgluteal approach was used according to the method of Bauer and Russe (5) with the patient in the lateral position. The hip abductor insertion site was roughened
leaving a bleeding bony surface and hip abductor refixation was performed using nonabsorbable transosseous sutures (Ethibond 3; Ethicon, Spreitenbach, Switzerland) tied using a modified Masson-Allen stitch (15, 16). To protect healing two crutches were used for six weeks with partial weight bearing.
Statistics The Fisher exact test was used for analysing categorical differences between the groups in terms of gender, presence of Trendelenburg sign and pertrochanteric tenderness, tendon defects and fatty infiltration. The nonparametric variables (WOMAC, HHS) preoperative to one-year follow-up were compared using the Wilcoxon sign rank test. The MannWhitney-U test was used for the comparison of continuous variables between groups of patients (age, BMI, WOMAC, HHS, hip abductor strength). All statistical analyses were performed using SPSS for Windows version 11.0 (SPSS Inc., Chicago, Illinois). A p-value ≤ 0.05 was deemed significant.
RESULTS From 40 patients with preoperative MR of the hip abductors, 20 patients showed a normal appearance of the hip abductor insertion and THA was performed using the direct anterior approach (group 1). In 20 patients partial to transmural tears of the anterolateral portion of the hip abductor insertion were recognised. Eight of them had THA through a direct anterior approach (group 2) and 12 through a transgluteal approach with repair (group 3). In terms of age, gender and body mass index no significant differences between the groups were found (Tab. I).
TABLE I - DEMOGRAPHIC DATA ON THE PATIENTS Group 1
Number of hips (n) Age
Group 2
Group 3
20
8
12
67 ± 12
73 ± 7
74 ± 7
18/2
8/0
11/1
25 ± 4
27 ± 4
31 ± 6
Gender (female/male) BMI (kg/m2)
P value 1/2
1/3
2/3
*ns
*ns
*ns
†
ns
*ns
†
ns
*ns
†
ns
*ns
BMI = body mass index. *MannWhitney-U test, †Fisher exact test. © 2014 Wichtig Publishing - ISSN 1120-7000
401
Abductor tears - Repair versus no repair
All but one patient with degenerative hip abductor tears were female. Different combinations and severities of partial and transmural hip abductor tears are summarised in Table II. No statistically significant difference was found between groups 2 and 3. Significant differences in minor fatty infiltration were only found for the gluteus minimus muscle
TABLE II - PREOPERATIVE HIP ABDUCTOR TEARS IN GROUP 2 (ANTERIOR APPROACH) AND GROUP 3 (TRANSGLUTEAL APPROACH) Group 2
Group 3
Partial anterior
1
1
Partial lateral
2
Transmural lateral
1
Transmural anterior + partial lateral
2 1
Transmural lateral and partial anterior
1
Transmural anterior and lateral
3
P value
†
ns
8
Fisher exact test.
†
between groups 1 and 2, and groups 1 and 3 (Tab. III). No significant difference in fatty infiltration was found between groups 2 and 3 (Tab. III). In terms of preoperative scores, the HHS and WOMAC were not statistically different between the groups (Tab. IV). In terms of preoperative Trendelenburg sign, pertrochanteric tenderness and hip abductor strength, no differences were encountered (Tab. IV). The WOMAC and HHS significantly improved after surgery in all 3 groups (Tab. IV). Significant improvement was recorded for the Trendelenburg sign in groups 1 and 2, for pertrochanteric tenderness in group 1 and 3 and for hip abductor strength in group 1 (Tab. IV). Whereas no significant difference with respect to the WOMAC and HHS was found one year postoperatively between the three groups (Tab. IV), the gain in terms of the HHS was significantly higher in group 1 (p = 0.045). Additionally, significantly fewer patients showed a positive Trendelenburg sign and significantly higher abductor strength was encountered for group 1 when compared to group 3. On conventional radiographs no signs of prosthetic loosening were detected. There were no significant differences in terms of femoral offset and leg length between the groups.
TABLE III - PREOPERATIVE FATTY INFILTRATION OF HIP ABDUCTORS (GOUTALLIER GRADES) P value† Group 1 Gluteus minimus
Cranial iliac crest
Caudal iliac crest
Gluteus medius
Cranial iliac crest
Caudal iliac crest
Group 2
Group 3
1/2
1/3
2/3
Anterior
1.6
1.5
1.67
ns
ns
ns
Middle
1.1
2.25
1.83
0.03
ns
ns
Posterior
0.25
1.25
1.58
0.02
0.01
ns
Anterior
1.05
0.88
0.92
ns
ns
ns
Middle
1.15
2.75
2.0
0.002
ns
ns
Posterior
0.25
1.25
0.75
0.003
ns
ns
Anterior
0.6
0.38
1.17
ns
ns
ns
Middle
0.4
0.25
0.67
ns
ns
ns
Posterior
0.25
0
0
ns
ns
ns
Anterior
0.4
0.63
0.75
ns
ns
ns
Middle
0.4
0.38
1.25
ns
ns
ns
Posterior
0.15
0.25
0.08
ns
ns
ns
Fisher exact test.
†
402
© 2014 Wichtig Publishing - ISSN 1120-7000
Betz et al
TABLE IV - CLINICAL OUTCOME Group 1 Preop
Postop
Group 2 P value
Preop
Postop
Group 3 P value
Preop
Postop
P value P value
1/2
1/3
2/3
Pre- Post- Pre- Post- Pre- Postop op op op op op Total WOMAC ± SD
6.3 ± 1
1.6 ± 1.6
41 ± 19.4
91 ± 13
‡
Trendelenburg (yes)
15
2
†
Hip abductor strength (M0-M5) ± SD
4 ± 0.6
4.7 ± 0.5
†
16
5
†
HHS ± SD
Pertrochanteric tenderness (yes)
2.2 ± 2.0
‡
