SURGICAL TECHNIQUE
RECOVERY FUNCTION SURVIVORSHIP DePuy believes in an approach to total hip replacement that places equal importance on recovery, function and survivorship.
The DePuy PROXIMA Hip System is indicated for primary hip arthroplasty when the surgeon wants to conserve bone and soft tissue, and provide physiological loading to the proximal femur. Ideally the femoral metaphysis should have a good margin of supportive proximal cancellous bone. 2
Contents Surgical Technique Patient Selection 4 Pre-operative Planning 5 Surgical Approach 6 Neck Resection 7 Acetabular Preparation 8 Canal Entry 9 Broaching - Initial Non Anatomic Cavity Preparation 10 Alignment Check 12 Broaching - Sequential Anatomic Preparation 13 Broaching - Final Anatomic Preparation & Calcar Milling 14 Trial Reduction 15 Final Implantation 16 Ordering Information 18 Surgical Technique Tips & Tricks 20 3
Patient Selection Within our DePuy Proxima Hip surgeon design team and in the hands of the most experienced surgeons, DePuy Proxima Hip is used as the standard stem in all cases where an uncemented implant could be used. Reproducible fixation and stability has led to its use in a wider selection of patients, and it is not merely reserved for the younger more active patients. While it is recommended that the prosthesis is initially implanted in patients with good bone stock and fairly normal anatomy, this indication can be broadened with increasing experience. However, there are clear contra-indications for the use of DePuy PROXIMA Hip: Hip dysplasia with severe neck anteversion or severe dysplasia of the proximal femur Severe osteoporosis Previous hip osteotomies Previous proximal femoral fractures DePuy PROXIMA Hip Surgeon Design Team: Prof. F. S. Santori Prof. I. Learmonth Prof. J. Grifka Dr. C. Valverde Prof. Y. H. Kim 4
Pre-operative Planning Pre-operative templating should be carried out to evaluate femoral and acetabular sizing (Figure 1). However, the philosophy of this implant is different from a conventional stem and size choice is strictly dependent on the bone quality. The femur should be slightly internally rotated for the A/P X ray. Templating should be performed both in AP and axial views. A true lateral view should also be obtained to assess the fit of the implant and filling of the femoral neck. The DePuy PROXIMA Hip philosophy is not to fill the metaphysis. In the A/P X-ray, the implant should be positioned centrally within the canal allowing a good cancellous margin medially and laterally. Figure 1 A/P X-ray template Note: restoration of the patient s natural biomechanics can be addressed through selection of either standard or high offset implants. Filling of the metaphyseal region of the proximal femur is not mandatory as long as the surgeon achieves absolute stability of the broach in the cancellous bone. In general a smaller implant is selected in the presence of good bone stock, where stability is provided by the strong supportive cancellous bone. In contrast, in the presence of osteoporosis with poor unsupportive cancellous bone, a larger implant is selected where increased cortical contact provides implant stability. 5
Surgical Approach Exposure may be achieved using a posterolateral, anterolateral, anterior or the MicroHip direct-anterior surgical approach to provide optimal visualisation of the acetabulum, the femoral neck and the proximal femur (Figures 2, 3 and 4). Figure 2 Posterolateral approach The DePuy PROXIMA Hip Round the Corner technique for femoral preparation allows maximum soft tissue preservation and protection of the abductor tendon insertions. The advantages of the Round the Corner technique are even more evident with minimally invasive surgery. Note: the high neck cut can cause some difficulty with acetabular exposure with an antero-lateral or MicroHip direct-anterior approach. Milling the calcar region before acetabular reaming may facilitate this phase of the operation. Figure 3 Anterolateral approach Figure 4 MicroHip direct-anterior approach 6
Neck Resection Neck resection is higher and more horizontal than for conventional THR, extending from the piriformis fossa to the head-neck junction (Figure 5). Resection may be performed either prior to or after dislocation, depending on the chosen surgical approach. With MicroHip or other mini anterolateral exposures, it is easier to resect the head in-situ. In such cases, a corkscrew may be used to assist removal of the femoral head. A knife may also be used to release any tissues from around the head and neck. Once the femoral preparation is finished, neck preparation may be completed using the calcar miller with the final broach in place. Figure 5 7
Acetabular Preparation The key points in acetabular reaming are as follows: Note: to maximise access to the acetabulum with a conservative neck resection, appropriate soft tissue release and adequate retraction should be performed. The use of a special reamer, shown here, avoids impingement on soft tissue. The creation of a hemispherical cavity with uniform bone-implant contact An adequate press-fit for initial stability Placement of the prosthesis at the anatomic centre of rotation of the hip joint, whenever technically possible The transverse acetabular ligament provides a useful guide to the orientation and placement of the cup. A reamer that is 6-8 mm smaller than the anticipated acetabular component should be used initially to deepen the acetabulum to the level determined by preoperative templating. All reamers should be introduced in 40-45 of abduction and 15 to 20 of anteversion (Figures 6 and 7). Figure 6 Note: if the patient is in a lateral decubitus position, the pelvis may be slightly flexed. 30 to 35 anteversion of the reamer handle and implant impactor is recommended to achieve the desired 15 to 20 of cup anteversion. Please refer to the Pinnacle Surgical Technique (Cat No 9068-80-050) or the DePuy ASR Surgical Technique (Cat No 9998-02-280) for detailed instruction on acetabular implantation. Figure 7 8
Canal Entry A dedicated DePuy PROXIMA canal finder awl is included in the instrument set. The awl should be placed in the centre of the postero-lateral quadrant of the resected neck to open up the femoral canal (Figure 8). The tip of the awl is initially directed laterally until the lateral flare is identified and then turned through 180 and advanced down the femoral canal. The proximal metaphyseal cancellous bone may be compressed by moving the canal finder medio-laterally (Figure 9). Anterior Lateral Medial Posterior The box osteotome is used only when very hard cancellous bone is encountered laterally, but should never invade the greater trochanter or the glutei insertion (Figure 10). Figure 8 Figure 9 Figure 10 9
Broaching - Initial Non Anatomic Cavity Preparation Following definition of the entry point and intra-medullary canal, the cavity initiator (S) 20-30 Strike Platform Hammering Portion broach is used to define the initial femoral envelope. Round the Corner is the term used to describe the movement devised to prepare the proximal femur for insertion of the DePuy PROXIMA Hip. With this technique the surgeon is able to protect the soft tissues, maintain the cancellous bone and provide the best possible load delivery on the lateral flare. The cavity initiatior (S) broach is first inserted at an angle of 20-30 to the long axis of the femur (Figure 11a). Once the lateral edge of the broach is below the greater trochanter, the broach 20-30 Figure 11a Strike Platform Hammering Portion is progressively aligned to the axis of the femur. Tilting the broach is achieved by hammering on the oblique portion of the strike platform and only a gentle pressure should be applied to the handle (Figure 11b). Broaching stops when neutral (or slightly valgus) alignment is achieved (Figure 12). Excessive force applied to the handle to gain alignment can cause a proximal femoral crack and should be avoided. Removal of the broaches is achieved with the same Round the Corner movement. Note: the use of the Round the Corner technique is to minimise the required impaction forces (by avoiding contact with cortical bone) and to ensure that the cavity created is the required size and shape Figure 11b (corresponding to the broach). 20-30 Figure 12 10
Broaching - Initial Non Anatomic Cavity Preparation The same technique is used with the lateraliser (L) broach (Figure 13) which develops the lateral envelope under the greater trochanter. The cavity starter (S2) broach continues the enlargement of the femoral cavity and development of the lateral flare (Figure 14). Alignment is checked frequently, using the alignment guide, both in the AP and ML planes (Figures 15 and 16). 20-30 Note: there are three non-anatomic broaches which are used sequentially prior to the First Anatomic Starter and sizing broaches. These broaches are marked as S, L, S2. It is desirable to obtain a few degrees of valgus with the smaller broaches to facilitate accurate alignment with the subsequent sizes. With Minimally Invasive Surgery the leg is positioned to present the resected neck in the wound. Precise broaching is then possible. Figure 13 20-30 Figure 14 11
Alignment Check DePuy Proxima Hip is a conservative implant with no diaphyseal stem extension to facilitate alignment. For this reason an external alignment system, consisting of a long extensible rod which can be quickly attached to the broach handle, has been introduced and should be used frequently during broaching. The alignment guide orbits the axis of the femur without pointing at any particular feature of the femur. Instead, when used as intended, the guide helps to align the axis of the broach or the implant with the axis of the femur by verifying that the axes in question are parallel to each other. Accurate alignment is achieved when the axis of the rod is parallel to the femoral axis in two perpendicular planes (Figure 15). The broach or the implant is correctly seated in neutral alignment when the rod of the alignment guide is parallel to the long axis of the femur in both the sagittal and coronal planes. Figure 15 Intraoperatively, the surgeon must identify the diaphyseal axis of the femur and use it as a reference. The easiest and most reproducible way is to use proximal and distal femoral landmarks. When parallel in the two planes, if the alignment rod is rotated and superimposed on the medial side of the greater trochanter (proximal femoral landmark) the guide will point at the centre of the knee (distal femoral landmark) and in an imaginary line drawn between these two points replicates the diaphyseal axis (Figure 16a). It is also possible to move the alignment guide to a perpendicular position against the broach plane and make sure that the alignment guide points at the medial femoral condyle (Figure 16b). It is then parallel with the long axis of the femur. Note: in cases where there is sclerotic bone, it may be useful to return to the starter broach or rasp to obtain initial alignment. It is important to obtain alignment at this stage before progressing to a larger broach. Figure 16a Figure 16b 12
Broaching - Sequential Anatomic Preparation Sequential broaching is carried out with the left or right first anatomic starter (SL, SR) broach. The first of the anatomic broaches enlarges the existing femoral cavity and provides an anatomic profile. This is further enlarged to the required size by subsequent broaches (sized). 20-30 Round the Corner broaching is used to prevent excessive removal of trochanteric bone, and allows the broach to follow the natural geometry of the proximal femur in both the A/P and M/L planes (Figures 15 and 16). The broach is introduced at an angle of 20-30 to the long axis of the femur and along the medial curve of the metaphysis. It should be brought into neutral alignment after the lateral edge of the broach is below the level of the greater trochanter (Figure 17). Figure 17 Care should be taken to preserve or restore femoral neck anteversion and to follow the shape of the proximal femur in three dimensions (Figure 18). Check that each broach is accurately aligned after seating. All broaching should be carefully performed and any aggressive movements avoided. A dedicated rasp may be used to help facilitate initial broaching if sclerotic bone is encountered anywhere within the region of the broach envelope. Note: it is worth reiterating that in the presence of strong cancellous bone, over correction into valgus with the smaller broaches is the best method of avoiding excessive varus with the final broach. Figure 18 13
Broaching - Final Anatomic Preparation & Calcar Milling 20-30 Sequential Round the Corner broaching continues from the size 1 anatomic (1L or 1R) broach. The final broach should fit the proximal femur, making sure sufficient good quality cancellous bone is left and rotational stability is achieved (Figure 19). The final implant size will correspond to the final broach used. The alignment of the broaches should be checked at regular intervals and adjusted if necessary. Final seating is achieved by impacting the broach in the axis of the femur. An intra-operative X-ray to check for correct sizing and alignment may be obtained at this stage. Figure 19 Once the final broach is fully seated and after leg length discrepancy has been checked, a calcar miller may be used to level the neck cut with the level of the DuoFix coating (Figure 20). A calcar miller with captured cutting-teeth is available as part of the DePuy PROXIMA Hip instrumentation. As previously advised, with the anterior, anterolateral, and MicroHip approaches, preservation of the neck may reduce acetabular exposure. In such cases, milling the neck first, may significantly help with acetabular preparation and cup positioning. Figure 20 14
Trial Reduction The correct combination of standard or high offset neck trial and modular head are selected to reproduce the patient s natural biomechanics as determined at pre-operative templating (Figure 21). Standard High Offset To optimise joint function and to increase stability, the largest diameter head possible is usually selected (Figure 22). A trial reduction is performed and the hip assessed through a full range of movement to identify any instability or impingement. Figure 21 Figure 22 15
Final Implantation 20-30 The definitive DePuy PROXIMA implant is introduced into the broach envelope with the same Round the Corner technique, using the stem inserter/impactor (Figure 23). The implant must follow the path of the last broach. The final implant should be seated (initially preferably by hand) as far into the broach envelope as possible without undue force. Before final impaction, it is crucial to use the alignment guide to confirm that the stem is in neutral alignment (Figure 24). Final seating is achieved with impaction in line with the femur. Figure 23 Impaction with the inserter/impactor is complete when the implant cannot progress any further and the DuoFix coating is level with or just proud of the resected neck. A change in pitch will be noted by the surgeon during impaction when final seating has been achieved. Over impaction of the definitive implant into the canal must be avoided. A further trial reduction must be performed to confirm final position. After trialling is completed, the taper must be irrigated and cleaned to ensure it is free of debris before lightly impacting the selected femoral head (Figure 25). Figure 24 Figure 25 16
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Ordering Information Implants 940050001 DePuy PROXIMA Hip Standard Offset L Size 1 940050002 DePuy PROXIMA Hip Standard Offset L Size 2 940050003 DePuy PROXIMA Hip Standard Offset L Size 3 940050004 DePuy PROXIMA Hip Standard Offset L Size 4 940050005 DePuy PROXIMA Hip Standard Offset L Size 5 940050006 DePuy PROXIMA Hip Standard Offset L Size 6 940050007 DePuy PROXIMA Hip Standard Offset L Size 7 940050008 DePuy PROXIMA Hip Standard Offset L Size 8 940050009 DePuy PROXIMA Hip Standard Offset L Size 9 940050011 DePuy PROXIMA Hip Standard Offset R Size 1 940050012 DePuy PROXIMA Hip Standard Offset R Size 2 940050013 DePuy PROXIMA Hip Standard Offset R Size 3 940050014 DePuy PROXIMA Hip Standard Offset R Size 4 940050015 DePuy PROXIMA Hip Standard Offset R Size 5 940050016 DePuy PROXIMA Hip Standard Offset R Size 6 940050017 DePuy PROXIMA Hip Standard Offset R Size 7 940050018 DePuy PROXIMA Hip Standard Offset R Size 8 940050019 DePuy PROXIMA Hip Standard Offset R Size 9 940050022 DePuy PROXIMA Hip High Offset L Size 2 940050023 DePuy PROXIMA Hip High Offset L Size 3 940050024 DePuy PROXIMA Hip High Offset L Size 4 940050025 DePuy PROXIMA Hip High Offset L Size 5 940050026 DePuy PROXIMA Hip High Offset L Size 6 940050027 DePuy PROXIMA Hip High Offset L Size 7 940050028 DePuy PROXIMA Hip High Offset L Size 8 940050032 DePuy PROXIMA Hip High Offset R Size 2 940050033 DePuy PROXIMA Hip High Offset R Size 3 940050034 DePuy PROXIMA Hip High Offset R Size 4 940050035 DePuy PROXIMA Hip High Offset R Size 5 940050036 DePuy PROXIMA Hip High Offset R Size 6 940050037 DePuy PROXIMA Hip High Offset R Size 7 940050038 DePuy PROXIMA Hip High Offset R Size 8 940050039 DePuy PROXIMA Hip High Offset R Size 9 PRX001A DePuy PROXIMA Hip Broaches 940090011 DePuy PROXIMA Hip Broach Left Size 1 940090012 DePuy PROXIMA Hip Broach Left Size 2 940090013 DePuy PROXIMA Hip Broach Left Size 3 940090014 DePuy PROXIMA Hip Broach Left Size 4 940090015 DePuy PROXIMA Hip Broach Left Size 5 940090016 DePuy PROXIMA Hip Broach Left Size 6 940090017 DePuy PROXIMA Hip Broach Left Size 7 940090021 DePuy PROXIMA Hip Broach Right Size 1 940090022 DePuy PROXIMA Hip Broach Right Size 2 940090023 DePuy PROXIMA Hip Broach Right Size 3 940090024 DePuy PROXIMA Hip Broach Right Size 4 940090025 DePuy PROXIMA Hip Broach Right Size 5 940090026 DePuy PROXIMA Hip Broach Right Size 6 940090027 DePuy PROXIMA Hip Broach Right Size 7 940070053 DePuy PROXIMA Hip First Anatomic Left 940070054 DePuy PROXIMA Hip First Anatomic Right PRX002A DePuy PROXIMA Hip Neck Segments 940090031 DePuy PROXIMA Hip Neck Segment Std Size 1 940090032 DePuy PROXIMA Hip Neck Segment Std Size 2/3 940090034 DePuy PROXIMA Hip Neck Segment Std Size 4/5 940090036 DePuy PROXIMA Hip Neck Segment Std Size 6/7 940090042 DePuy PROXIMA Hip Neck Segment High Size 2/3 940090044 DePuy PROXIMA Hip Neck Segment High Size 4/5 940090046 DePuy PROXIMA Hip Neck Segment High Size 6/7 PRX003 Generic Instrumentation 940080001 DePuy PROXIMA Hip Canal Finder Awl 940070049 DePuy PROXIMA Hip Stem Alignment Guide 940080004 DePuy PROXIMA Hip Stem Inserter/Impactor 940080007 DePuy PROXIMA Hip MI Calcar Reamer Small 940070050 DePuy PROXIMA Hip Cavity Initiator (S) Broach 940080008 DePuy PROXIMA Hip Lateraliser (L) Broach 940070051 DePuy PROXIMA Hip Cavity Starter (S2) Broach 940080030 DePuy PROXIMA Hip Case 2 Complete 940080020 DePuy PROXIMA Hip Case 1 Complete 940090009 DePuy PROXIMA Hip Broach Handle 18
PRX004 DePuy PROXIMA Hip Large Sizes 940090018 DePuy PROXIMA Hip Broach Left Size 8 940090019 DePuy PROXIMA Hip Broach Left Size 9 940090028 DePuy PROXIMA Hip Broach Right Size 8 940090029 DePuy PROXIMA Hip Broach Right Size 9 940090038 DePuy PROXIMA Hip Neck Segment Std Size 8/9 940090048 DePuy PROXIMA Hip Neck Segment High Size 8/9 H143 DePuy PROXIMA Hip 940090200 DePuy PROXIMA Hip Sizes 1-9 X-ray Templates 200231000 Anteversion Osteotome Small 853965 S-ROM T-Handle ROP001 Olive Shaped Broach 19
This publication is not intended for distribution in the USA. DePuy PROXIMA Hip, DePuy ASR, DuoFix and MicroHip are trademarks of DePuy International Ltd. Pinnacle is a trademark and Articul/eze, Porocoat and S-ROM are registered trademarks of DePuy Orthopaedics, Inc. 2007 DePuy International Limited. All rights reserved. Cat No: 9400-70-000 version 3 DePuy International Ltd St Anthony s Road Leeds LS11 8DT England Tel: +44 (113) 387 7800 Fax: +44 (113) 387 7890 Issued: 08/07