An extended posterior approach to the hip and pelvis for complex acetabular reconstruction that preserves the gluteal muscles and their neurovascular supply

Reconstruction of the hip abductor function with a deep muscle-sparing vastus lateralis to gluteus medius translational transfer/transposition : early results of a multidisciplinary team approach

Aims

The aim of this study is to describe a deep muscle-sparing vastus lateralis (VL) flap to gluteus medius (Gmed) transfer to address severe hip abductor function deficiency, and present the early results achieved through a multidisciplinary team (MDT) approach.

Methods

Seven patients, with and without previous total hip arthroplasty, with severe abductor deficiency of the hip (Medical Research Council ≤ 2/5), and requiring walking aids, underwent a deep muscle-sparing VL translation flap to Gmed as part of a new orthopaedic and plastic MDT approach, and had more than 12 months' follow-up. The fatty infiltration of the glutei had a median Goutallier scale of 4 (IQR 1 to 4). Five patients had prior revision surgery, two involving a proximal femoral arthroplasty. Patients underwent pre- and postoperative evaluations with clinical examination, instrumented gait analysis, surface electromyography (EMG), and MRI.

Results

All patients were satisfied with the result and could walk without support by six months after surgery. The abductor power improved to 3 to 5 out of 5 and continued to improve beyond one year after surgery. Knee extension power was not affected. EMG demonstrated that the transferred VL activated synchronously with Gmed three months postoperatively, suggesting adaptation to its new function. MRI demonstrated no fatty infiltration of the flap or the residual VL.

Conclusion

The MDT approach to hip abductor function reconstruction with VL to Gmed transfer has demonstrated potential for success, with good functional outcomes and no functional donor-site morbidity recorded to date.

Revision Hip Arthroplasty Through a Gluteal-Sparing Extended Posterior Approach May be Able to Achieve Similar Functional Outcomes to Primary Hip Arthroplasty

Background

Revision total hip arthroplasty (THA) has been reported to have worse outcomes when compared to primary procedures, which may, in part, be due to the increased exposure required for the procedure. We aimed to investigate the postoperative functional outcomes of 2 groups of primary and revision THA, when revision procedures were performed using a gluteal-sparing extended posterior approach.

Methods

Two groups of 51 primary and 21 revision THAs were prospectively recruited from a single center between 2016 and 2019. Both groups were assessed preoperatively using quantitative gait analysis and patient-reported outcomes, and at 3 and 12 months postoperatively. Hip and knee kinematics were computed from motion capture data acquired at the gait analysis. Kinematic and patient-reported outcome measures data were analyzed using linear mixed models. Statistical parametric analysis complemented the main analysis of the kinematics.

Results

Patients in the primary group had worse preoperative patient-reported outcome measures when compared to the revision group. There were no between-group differences in walking speed. Hip extension in late stance phase of gait was 9° and 5° lower for the revision group when compared to the primary group at 3 and 12 months, respectively. These differences were not statistically significant, but the magnitude of the effect size was noteworthy suggesting a functional deficit (Cohen's d = 0.64 and 0.54, respectively).

Conclusions

Revision THA using a gluteal-sparing extended posterior approach may be able to achieve similar patient-reported and gait outcomes with those of primary THA within the first 12 postoperative months.

Can surface landmarks help us identify the gibson interval during surgical hip dislocation: a study of 617 hips

INTRODUCTION

The Gibson approach, used in hip-preserving surgery, is intermuscular and develops the space anteriorly to the gluteus maximus. Reliable anatomical landmarks for the development of this interval do not exist, but the interval is marked by perforating vessels (PV) of the inferior gluteal artery. The aim of this study was to provide reference values for the relationship between palpable anatomical landmarks on the femur/pelvis and the anterior border of the gluteus maximus using CT scans of the proximal femur.

MATERIALS AND METHODS

Single center retrospective study of 617 hips who underwent a CT-scan of the pelvis/femur. We defined 5 anatomical markers on the pelvis and proximal femur and measured the distance of the anterior border of the gluteus maximus in relation to the marker, which was either anterior or posterior. The amount PV's and it's location relative to the innominate tubercle were measured in the coronal plane. For each landmark we compared these subgroups: male vs female, age < 40 vs ≥ 40, categorical age (< 20; 20-40; 40-60; > 60), and categorical femoral torsion (< 10°; 10°-25°; 25°-35°; > 35°).

RESULTS

Mean location of the parameters A-E was at - 8.1 cm, 1.1 cm, 1.8 cm, 1.3 cm and 0.4 cm. Parameters B, C, and D were more posterior in the age ≥ 40 group. Parameters A-E were significantly more posterior in the age > 60 group. Parameters A and E were significantly more anterior in females than in males. 50% of the PV are found between 5 and 9 cm proximal to the innominate tubercle. No statistically significant differences were noted in the location of any of the perforating vessels in the different subgroups.

CONCLUSION

The Gibson interval is located more anteriorly in female patients and patients under 40 years of age. It is located more posteriorly in patients over 60 years of age. In addition, the interval moves anteriorly with increasing femoral torsion, most notably in patients with very high femoral torsion (> 35°).

A Gluteus Medius Muscle Biopsy to Confirm Amyloid Transthyretin Deposition in Wild-type Transthyretin Cardiac Amyloidosis: A Report of Two Cases

In patients with wild-type transthyretin cardiac amyloidosis (ATTRwt-CA), the uptake of the tracer on technetium-99m-labeled pyrophosphate (99mTc-PYP) scintigraphy, which indicates amyloid transthyretin (ATTR) per se, is often observed in skeletal muscles, such as the abdominal oblique and gluteal muscles. Among extracardiac biopsies for confirming ATTR deposition in ATTRwt-CA, a 99mTc-PYP imaging-based computed tomography (CT)-guided core needle biopsy of the internal oblique muscle has relatively high sensitivity. In some patients, the 99mTc-PYP uptake is more pronounced in the gluteal muscles than in oblique muscles. We herein report two cases of ATTRwt-CA in which a CT-guided biopsy of the gluteus medius muscle with 99mTc-PYP uptake confirmed the presence of ATTR deposits.

Virtual biomechanical assessment of porous tantalum and custom triflange components in the treatment of patients with acetabular defects and pelvic discontinuity

Aims

The aim of this study was to compare the biomechanical models of two frequently used techniques for reconstructing severe acetabular defects with pelvic discontinuity in revision total hip arthroplasty (THA) - the Trabecular Metal Acetabular Revision System (TMARS) and custom triflange acetabular components (CTACs) - using virtual modelling.

Methods

Pre- and postoperative CT scans from ten patients who underwent revision with the TMARS for a Paprosky IIIB acetabular defect with pelvic discontinuity were retrospectively collated. Computer models of a CTAC implant were designed from the preoperative CT scans of these patients. Computer models of the TMARS reconstruction were segmented from postoperative CT scans using a semi-automated method. The amount of bone removed, the implant-bone apposition that was achieved, and the restoration of the centre of rotation of the hip were compared between all the actual TMARS and the virtual CTAC implants.

Results

The median amount of bone removed for TMARS reconstructions was significantly greater than for CTAC implants (9.07 cm3 (interquartile range (IQR) 5.86 to 21.42) vs 1.16 cm3 (IQR 0.42 to 3.53) (p = 0.004). There was no significant difference between the median overall implant-bone apposition between TMARS reconstructions and CTAC implants (54.8 cm2 (IQR 28.2 to 82.3) vs 56.6 cm2 (IQR 40.6 to 69.7) (p = 0.683). However, there was significantly more implant-bone apposition within the residual acetabulum (45.2 cm2 (IQR 28.2 to 72.4) vs 25.5 cm2 (IQR 12.8 to 44.1) (p = 0.001) and conversely significantly less apposition with the outer cortex of the pelvis for TMARS implants compared with CTAC reconstructions (0 cm2 (IQR 0 to 13.1) vs 23.2 cm2 (IQR 16.4 to 30.6) (p = 0.009). The mean centre of rotation of the hip of TMARS reconstructions differed by a mean of 11.1 mm (3 to 28) compared with CTAC implants.

Conclusion

In using TMARS, more bone is removed, thus achieving more implant-bone apposition within the residual acetabular bone. In CTAC implants, the amount of bone removed is minimal, while the implant-bone apposition is more evenly distributed between the residual acetabulum and the outer cortex of the pelvis. The differences suggest that these implants used to treat pelvic discontinuity might achieve short- and long-term stability through different biomechanical mechanisms.

Posterior Exposure in Kocher-Langenbeck With Gluteus Minimus Debridement vs. the Gibson Approach: A Cadaveric Study

OBJECTIVE

To quantify the posterior acetabular exposure achieved with the Kocher-Langenbeck (K-L) with gluteus minimus debridement and Gibson approaches.

METHODS

A Kocher-Langenbeck approach and a subsequent Gibson approach on the contralateral hip were performed in the prone position on 9 fresh frozen cadavers. Calibrated digital images were obtained of the Kocher-Langenbeck exposure, Kocher-Langenbeck exposure after gluteus minimus debridement, and Gibson exposure. The surface area of the posterior hip and pelvis visualized with each approach was calculated and compared with the contralateral side to assess for the difference between exposures.

RESULTS

In 5 of the 9 cadavers, the Kocher-Langenbeck exposure before gluteus minimus debridement yielded an increased exposure in comparison with the Gibson approach, and the exposure was equivocal in 3 specimens. An increase of greater than 10% was considered significant. The exposure increased anteriorly and cranially by an average of 13.1 cm 2 after debridement of the gluteus minimus caudal to the superior gluteal neurovascular bundle in the Kocher-Langenbeck approach.

CONCLUSIONS

Debridement of the gluteus minimus caudal to the level of the superior gluteal neurovascular bundle can significantly increase anterior and cranial exposure in the Kocher-Langenbeck approach and provide similar areas of access when compared with that in the Gibson approach.

Exposure Provided by the Gibson Versus the Kocher-Langenbeck Approaches With and Without Trochanteric Osteotomy: A Cadaveric Mapping Study

OBJECTIVE

To determine if prevalent approaches in acetabular fracture surgery provide enhanced anterior and cranial exposure in a cadaveric model.

METHODS

A Kocher-Langenbeck (K-L) approach (followed by a Gibson approach on the contralateral hip) was performed in the lateral position on 8 cadavers. A Steinmann pin was used to create holes outlining the bony surfaces available for instrumentation before and after a trochanteric osteotomy. All soft tissue was then removed from the pelvis, and a calibrated digital picture was taken. The surface area of the pelvis visualized through each approach was calculated and compared with the contralateral side to assess for a difference in exposure between the Gibson approach and the K-L approach. An increase in exposure of greater than 10% was considered significant. The extent of anterior exposure (with and without a trochanteric osteotomy) was then measured from the greater sciatic notch.

RESULTS

In 2 of 8 cadavers (25%), the Gibson approach yielded an increase in exposure when compared with a K-L approach. The addition of a trochanteric osteotomy yielded on average 1.6 cm (range, 0.7-2.6 cm) of increased anterior exposure in the K-L approaches and 1.5 cm (range 0.9-3.1 cm) in the Gibson approaches.

CONCLUSION

The Gibson approach did not reliably provide increased anterior exposure compared with a K-L approach in a cadaver model. A trochanteric osteotomy can be expected to add 1-2 cm of increased anterior exposure in both approaches.

The Stability of the Porous Tantalum Components Used in Revision THA to Treat Severe Acetabular Defects: A Radiostereometric Analysis Study

BACKGROUND

The acetabular components used in revision total hip arthroplasty (THA) to treat severe acetabular bone defects have high rates of re-revision at mid to long-term follow-up. Early translation of acetabular components used in revision THA is a good predictor of later loosening, and radiostereometric analysis (RSA) is the most sensitive method to measure migration. The objectives of the present study were to use RSA to compare the migration of the porous tantalum acetabular components used to treat severe bone defects with the previously established acceptable proximal translation threshold of ≤1 mm within 2 years, and to determine the effect on migration of the addition of inferior screws through the component into the ischium or pubis.

METHODS

RSA was utilized to measure the migration of 55 porous tantalum components used to treat severe acetabular defects (28 Paprosky IIIA, 27 Paprosky IIIB; 21 hips with pelvic discontinuity) at a mean follow-up of 4 years (range, 2 to 12 years).

RESULTS

Forty-eight of the 55 components migrated less than the threshold that predicts later loosening (>1 mm) and 50 had not been re-revised at the time of the latest follow-up. Seven components, none of which had inferior screw fixation, exceeded the translation threshold. Of these, 6 were implanted to treat pelvic discontinuity. Of those 6 components, 5 were re-revised for loosening related to patient symptoms. At 2 years, the absolute median proximal translation of components with inferior screw fixation was |0.3| mm (range, |0.1| to |0.9| mm), compared with |0.4| mm (range, |0.03| to |16.4| mm) for those without inferior screws (p = 0.04).

CONCLUSIONS

As measured with use of RSA, the majority of porous tantalum acetabular components used in a revision THA to treat severe acetabular defects had acceptable early migration. This predicts good long-term survivorship of these components. The use of inferior screws further improved acetabular component fixation.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Versatility of an Extended Posterior Approach for the Treatment of Acetabular Fractures With Reference to the Superior Gluteal Neurovascular Bundle

The superior gluteal neurovascular bundle is at risk of injury in certain types of acetabular fractures and the associated surgery. This article describes the versatility of an extended posterior approach, previously described for complex revision total hip replacement (the Adelaide approach) and for the treatment of acetabular fractures that allows a wide exposure of the ilium through identification, protection, and mobilization of the superior gluteal neurovascular bundle.

Exposure of the superior gluteal neurovascular bundle for the safe application of acetabular reinforcement cages in complex revisions

The posterior approach to the hip is the most common extensile approach used, however exposure is limited superiorly by the superior gluteal neurovascular bundle (SGNB). The extra-pelvic course of the SGNB demonstrates variability between individuals, occasionally located only 1 cm from the acetabular rim. In complex acetabular reconstructions where the application of a reinforcement cage maybe required protecting the SGNB is challenging. The flanges of these cages are designed to sit on the ilium superior to the acetabular rim and to receive screws for fixation. The application of such cages may result in iatrogenic injury to the SGNB by way of forceful retraction or entrapment. We describe a technique that involves exposure and release of the SGNB such that the flanges of cage constructs may be safely applied.

Does cup-cage reconstruction with oversized cups provide initial stability in THA for osteoporotic acetabular fractures?

BACKGROUND

The incidence of acetabular fractures in osteoporotic patients is increasing. Immediate total hip arthroplasty (THA) has potential advantages, but achieving acetabular component stability is challenging and, at early followup, reported revision rates for loosening are high.

QUESTIONS/PURPOSES

This study measured acetabular component stability and the initial surface contact achieved between the acetabular component and unfractured region of the pelvis after THA using an oversized acetabular component and cup-cage reconstruction.

METHODS

Between November 2011 and November 2013, we treated 40 acute acetabular fractures in patients older than 70 years of age. Of these, 12 (30%) underwent immediate THA using an oversized acetabular component with screws inserted only into the ilium and a cup-cage construct. Postoperatively all patients were mobilized without weightbearing restrictions. Indications for immediate THA after acetabular fractures were displaced articular comminution deemed unreducible. Eleven of the 12 were prospectively studied to evaluate the initial stability of the reconstructions using radiostereometric analysis. One of the patients died of a pulmonary embolism after surgery, and the remaining 10 (median age, 81 years; range, 72-86 years) were studied. Of these, five were analyzed at 1 year and five were analyzed at 2 years. Acetabular component migration was defined as acceptable if less than the limits for primary THA that predict later loosening (1.76 mm of proximal migration and 2.53° of sagittal rotation). The contact surface between the acetabular component and ilium in direct continuity with the sacroiliac joint, and the ischium and pubis in direct continuity with the symphysis pubis, was measured on postoperative CT scans.

RESULTS

At 1 year the median proximal migration was 0.83 mm (range, 0.09-5.13 mm) and sagittal rotation was 1.3° (range, 0.1°-7.4°). Three of the 10 components had migration above the suggested limits for primary THA at 1 year postoperatively. The contact surface achieved at surgery between the acetabular component and pelvis ranged from 11 to 17 cm(2) (15%-27% of each component).

CONCLUSIONS

The majority of acetabular components in this cohort were stable despite the small contact surface achieved between the component and pelvic bone. Three of 10 migrated in excess of the limits that predict later loosening in primary THA but it remains to be seen whether these limits apply to this selected group of frail osteoporotic patients. We continue to use this technique routinely to treat patients with the same indications, but since the analysis of these data we have added screw fixation of the acetabular component to the ischial tuberosity and the superior pubic ramus.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Selecting the surgical approach for revision total hip arthroplasty

Selecting the approach for revision total hip arthroplasty is a crucial step in pre-operative planning. Whether the surgical objectives can be reached via a conventional approach or require a specific approach must be determined. The best approach depends on multiple factors including the reason for revision, patient's characteristics, implants requiring removal, previous approach, soft tissue and bone lesions, and surgeon's level of experience. These factors are discussed herein, as well as the potential and limitations of conventional approaches and the indications for specific approaches.