Navigation of total hip replacement has been introduced in the field of orthopaedic surgery at the beginning of the 21st century. The main objective of such technique is to provide intra-operative quantitative data to improve clinical outcomes. Two major aspects of hip replacement are covered: a) leg length and offset control; b) cup orientation. CT-based as well as CT-free solutions have been developed. In this paper, we will describe in detail how a universal image free systems can be used to fulfill any clinical situation and any surgical philosophy. The Total Hip Surgetics software is in use since 2005 in our department; the first clinical results show an improvement in 18% of the leg length and offset control. This values goes up to 38% concerning the length control only.
We report here the study of a personal series of 129 consecutive femoral impaction grafting during hip revision replacement performed between January 1991 and December 2005. The indication for the revision of the femoral component was aseptic loosening in 127 hips and septic loosening in two. The precise locations of the segmental defects and osteolytic areas were determined and classified, with use of the Endo-Klinik System, as follows: grade 2 in 75 hips, grade 3 in 43, and grade 4 in 11. Removal of the components, debris and cement was done with special care to achieve a complete resection of fibrous tissue in the medullary canal to ensure a direct contact between the graft and the host bone. Before impaction grafting, femoral segmental bone defects or windows were reconstructed and reinforced with strut allograft and cerclage wires. We used in all hips a special revision set of instruments specially designed for impaction grafting. All the acetabular cups were also revised. Clinical and radiologic evaluation was performed at six weeks, three months, six months and one year. Then, patients were reviewed every year for the first five postoperative years and every two years thereafter. A survivorship analysis was performed to determine the overall success of the procedure. Failure was defined as an implant that had been revised or that was radiologically loosened at the time of follow-up. The survival curve was derived from the cumulative survival rate over time, as calculated from the actuarial life table. At the last follow-up evaluation, seven patients (seven hips) had died and two (two hips) were lost to follow-up. The follow-up of these nine patients ranged from two to ten years. One hundred and twenty patients (120 hips) were reviewed with a mean follow-up of 8.2 years (range, two to 16 years). The average follow-up of the whole series was 8.4 years (range, two to 16 years). At the time of the final review 1 of the 129 hips had migration of the stem’s cement mantle relative to the bone (5 mm) with lucent lines at the graft-host interface in three Gruen zones. Another one had migration within the cement (8 mm) with lucent line at the distal graft-host interface and a distal fracture of the cement mantle. These two stems were considered as definitely loosed according to the criteria of Johnston et al. but none of them was revised. The remaining 127 hips showed no radiological changes at the latest examination concerning stem migration and radiolucent lines. One acetabular definite loosening occurred at ten years and was revised at 11 years postoperatively. In this respect, of the 129 hips, only one hip was revised at 11 years’ follow-up (0.7%). The survivorship analysis, with radiologic loosening as the endpoint, yielded a 98% cumulative survival rate for the femoral component and for the acetabular component, 99% at eleven years follow-up. The survival rate with revision for any reason as the endpoint was 99.4% at eleven years follow-up. The results observed in this series, regarding the need for a repeat revision for any reason, are in agreement with the excellent outcome reported by other authors using similar technique. Nevertheless two main differences must be emphasized when comparing the results of this study with the others. The first one is the low rate of subsidence and the second is the absence of postoperative femoral fracture. The quality of bone grafting and the use of a Kerboull stem, double tapered and polish, were associated with the very low rate of distal migration. The unconditional reconstruction of distal bone deficiency or weakness with bone graft strut appeared efficient to prevent the occurrence of femoral fracture, despite the unique use or standard stems.
Established lower limb alignment and knee stability are the two main prognosis factors influencing good functional result and prosthesis life. During Total Knee Arthroplasty (TKA), correction of tibial extra-articular deformity cannot be achieved without ligament balancing. Excessive valgus deformity after a failed high tibial osteotomy (HTO) necessitates a much larger resection of bone from the medial tibial plateau resulting in a trapezoidal extension gap. In overcorrected valgus knee patients after failed HTO, meticulous preoperative planning is required to predict complementary procedures needed to achieve flexion-extension balance with optimal postoperative lower limb alignment. This article details the preoperative planning involved and the intraoperative technique used in such cases. We describe a planning methodology consisting of measuring medial and lateral distance between future femoral and tibial orthogonal resection lines, drawn on valgus and varus stress radiographs (arrows). If the medial distance (medial arrows) on the valgus stress radiographs is longer than the lateral arrows on the varus stress radiographs, a lateral release will be necessary to achieve a rectangular extension gap during TKA procedure. However, the lateral release needed to compensate medial bone resection is limited. This limit must not exceed 10 millimeters (about 8 to 10° of valgus malunion). Over this limit, total knee arthroplasty plus corrective tibial osteotomy is one of the solutions. We prefer to insert prosthesis inside the “ligament box”; without any ligamentous release. The limb alignment is achieved with corrective tibial osteotomy. We propose and describe how to carry out TKA based on a rectangular extension gap, associated, in the same procedure, with a HTO to restore a neutral alignment of the leg.
The degenerative cascade in the lombar spine can go through a phase of destabilization where abnormal motion due to the loss of segmental rigidity can cause pain, be it low back pain or redicular pain. In this phase where lesions still allow for some motion and before natural restabilization, dynamic stabilization is a treatment that allows for bringing the spine back into a pain free situation. After 14 years of clinical use and almost 40 000 patient treated with dynamic stabilization, Dynesys ® has clearly defined its field of application as well as its limitations. We will reported the surgical techniques and clinical results and shown the evolution of the device with open screws and DTO ™ system, which permits fused and non-fused solution in the same patient with an “on line” device.
Despite increasing advantages in biomaterials, prosthetic designs, and implant fixation, clinical outcome of total hip arthroplasty (THA) has 10% failure rate after 10 years. Component malposition is well known to be responsible for instability, impingement, excessive wear and early loosening. Computer-assisted procedures are expected to improve the accuracy of the components positioning and also the outcome of total hip replacements. We present the Amplivision. system (Amplitude, Porte-du-Grand-Lyon, Neyron, France) that has been used since October 2005 for total hip replacements at our institution. The surgical technique as well as the advantages of this system is described. The Amplivision© system allows accurate positioning of the acetabular and femoral components during THA and also the control of leg lengthening, offset and stability.
Total knee arthroplasty in the valgus knee poses specific problems to the surgeon, such as the presence of ligament tightness on the lateral side. It has been claimed in the past that approaching the knee from the lateral side through a lateral parapatellar arthrotomy may therefore be a more logical and easier technique than the standard medial approach used conventionally. Many surgeons however do not wish to change their routine practice and therefore wish to stick to the classical medial approach they are used to, even in the presence of an underlying valgus deformity. In this paper, we therefore report the technical considerations that one should take into account when addressing the valgus knee through a standard medial approach. These include tightness of the lateral soft tissues, stretching of the medial collateral ligament, lateral bowing of the femoral shaft, and a tendency for lateralized patellar tracking. A review of 125 consecutive valgus knees treated at our institution through a standard medial approach while using these principles, has demonstrated an excellent operative outcome in the majority of cases.
We treated 13 patients who had a fixed valgus deformity of the knee with a semiconstrained total knee arthroplasty combined with advancement of the lateral collateral ligament by means of a lateral femoral condylar sliding osteotomy. At follow-up of between one and 6.5 years all patients were assessed using the Knee Society score. The mean knee score improved from 32 to 88 and the functional score from 45 to 73. The mean tibiofemoral angle was corrected from 191 degrees to 180 degrees. There was no postoperative tibiofemoral or patellar instability and, in most knees, distal transposition of the lateral femoral condyle achieved satisfactory stable alignment.
Restoration of a painless hip joint capable of bearing weight by uncemented implantation of a rotationally stable, modular revision stem anchored in the diaphysis.
Massive postoperative subsidence of the prosthesis is a major failure concern in revision hip replacement, as it can potentially provoke recurrent dislocation, secondary femoral fracture, and discrepancies in leg length. In this study, we aimed to evaluate whether the use of vibration-assisted broaching would offer the requisite control and reproducibility necessary to achieve axial stability for a tapered, rectangular revision stem in patients undergoing hip revision surgery. We evaluated the performance of the Zweymüller femoral revision stem implanted following pneumatic rasping in 61 patients (62 hips). There were 39 females and 22 males with a mean age of 72 years. Aseptic loosening was the indication for revision in most cases. According to the Paprosky classification, defects of the femur were grade 2 in 14 hips, grade 3 in 44 hips, and grade 4 in four hips. Ninety percent of the surgeries were first revisions. In the majority of procedures (58 procedures), we utilized anterolateral abductor splitting with the patient in the lateral position as our surgical approach. In six cases, we performed windowing of the femur diaphysis to facilitate cement removal. An extended trochanteric osteotomy was performed in two cases. In all cases, the femoral bed of the implant was modelled at the time of operation using progressively larger pneumatic broaches of 18–22 cm in length. The mean preoperative Postel Merle d’Aubigné (PMA) score was 9, which improved to 16.4 at the time of the last follow-up (mean: 4.8 years; range 3–7 years). No implant showed evidence of significant migration or loosening. During the operation, the specific use of the pneumatic hammer did not cause any complications. In conclusion, the use of the Zweymüller femoral revision stem implanted following pneumatic rasping potentially minimizes complications and maximizes benefits. An extended follow-up is required to better understand the potential long-term benefits of this approach.
Background: Malpositioning of the acetabular component during total hip arthroplasty increases the risk of dislocation, reduces the range of motion, and can be responsible for early wear and loosening. The purpose of this study was to compare computer-assisted with freehand insertion of the acetabular component. Methods: A randomized, controlled, matched prospective study of two groups of thirty patients each was performed. In the first group, cup positioning was assisted by an imageless computer-assisted surgical system based on bone morphing. In the control group, the cup was placed freehand. All of the patients were operated on by the same surgeon through an anterolateral approach. Cup anteversion and abduction angles were measured on three-dimensional computed tomography reconstructions postoperatively for each patient by an independent observer using special cup-evaluation software. Results: There were sixteen men and fourteen women in each group, and the mean body-mass index was approximately 25 in each group. The computer-assisted procedure took a mean of twelve minutes longer than the freehand procedure. Fifty-seven percent (seventeen) of the thirty cups placed freehand and 20% (six) of the thirty in the computer-assisted group were outside of the defined safe zone (outliers). This difference was significant (p = 0.002). There were no differences between the computer-assisted group and the freehand-placement group with regard to the mean abduction and anteversion angles, but there was a significant heterogeneity of variances, with the lowest variations in the computer-assisted group. Conclusions: Use of an imageless navigation system can improve cup positioning in total hip arthroplasty by reducing the percentage of outliers. Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.
The Mobi-C® cervical disc replacement is a semi-constrained prosthesis with a mobile polyethylene insert situated between two chrome cobalt plates. The insert can slide. Overall the Mobi-C® device has five degrees of freedom. The primary indications are as follows: 1) soft herniated discs leading to cervicobrachial pain refractory to conservative treatment; 2) some cases of hard herniated discs if movement has been documented on intra-operative dynamic bending films; 3) much more rarely in cases of spinal cord compression with myelopathy. Technically, centering of the device is facilitated by the dedicated instrument system. Regarding the results, the clinical efficacy is conventional. Mobility is preserved at a minimum 2-year follow-up in 85.5% of the devices. The main mechanical complications are radiological adjacent syndrome and heterotopic ossification (HO), among which even those of class III permit residual movement.
Since November 2004 we have been using a modular short-stem hip prosthesis with a less invasive anterolateral approach in 154 cases. The modified Watson-Jones [1] approach allows the insertion of the hip prosthesis without detaching muscles. The modularity of the prosthesis offers the choice of different degrees of anteversion and CCD angles to restore hip biomechanics. This is simulated by the navigation system. We evaluated primary stability, ease of minimally invasive implantation and restoration of biomechanics. We found good functional results and a low complication rate, without any dislocation. The navigation helps to insert the cup more precisely and to restore the center of rotation, leg length and offset. It suggests the best choice of modular neck to use and helps to predict and influence the safe range of motion. The emphasis is placed on the description of the surgical steps.
The anterior approach to the hip, initially described by Hueter, has been modified and used by Jean and Robert Judet since 1947 for fixing an acrylic prosthesis [1,2]. In 1993, Marc Siguier rendered this approach completely mini-invasive by avoiding any muscular desinsertion or sectioning of tendons [3]. When we learnt about the possibilities of using the navigation technique for a hip prosthesis using the Orthopilot system, we decided to combine these two innovations so as to induce a minimum of aggression and a maximum of security while fixing a hip prosthesis. A study carried out on the positioning of the acetabulum, with or without navigation, as well as a comparison between two navigation systems are mentioned in an attempt to validate the relevance of the frame of references.
In case of severe femoral bone loss, cementless revision hip arthroplasties require a stable initial distal fixation that does not compromise a subsequent bone reconstruction. The locking mechanism provides initially reliable fixation, especially if bone loss has spread to the distal femoral isthmus or when an extended trochanteric osteotomy (femorotomy) is indicated. Locking stems can be used in all types of femoral revision, but this type of implant can be especially useful in case of diaphysial damage (beyond the isthmus) which makes fixation of a long cemented or non-cemented stem uncertain; in case of septic revisions which need a careful femoral cleaning; in case of peri-prosthetic fractures or if surgical complications (false route, fracture, perforations) occur that impair fixation of a cemented stem or one that is not of standard length. All approaches may be used, but the need for access to the femur dictates choice of the antero-lateral and especially the postero-lateral route. The choice of diameter is guided by “press-fit” beyond the femorotomy, thus minimizing the stresses that will consequently be exerted on the locking system. The size will be chosen also to optimize the contact between residual bone and prosthetic surface treatment in the metaphysial proximal and diaphysial regions. The stem must be locked depending a few technical requirements. The position of the stem will be chosen regarding limb length (height) and joint stability (anteversion). The quality of femorotomy closure is evaluated by achieving broad contact between the flap and the proximal part of the stem. When the medial part of the femur relative to the flap remains distant from the stem, a “counter-femorotomy” of medial cortical bone made at a different level should be performed to optimize contact. These implants simplify femoral revisions by facilitating femorotomy in complex situations. This method offers constant bone reconstruction without significant bone grafting and durable fixation if locking mechanism is added to an adjusted implant in contact with native bone, limiting short-and long-term stresses on it.
The implantation of a « Charité » prosthesis has to be solved through a biomechanical compromise between the size of the implants and it’s positioning in the intervertebral space. A retroperitoneal approach allows one to minimise complications and especially to see and protect the hypogastric nerve. Generally, the anatomy of the great vessels offers a wide approach on the anterior aspect of the disc, except in the case of a high bifurcation of the vena cava with a left iliac vena outside and over the iliac artery and having a straight downwards direction. This situation is infrequent, 1 for 1,000 anterior approaches in our experience.
Total disc arthroplasty for lumbar spine is a new solution for low back pain treatment after adequate patient selection. The surgical technique starts with a morphological and anatomical analysis to eliminate surgical exposure problems. The surgical approach is retroperitoneal from the left or the right side after horizontal skin incision. Video-assistance improves vision and allows minimal invasive exposure. At level L5-S1, the exposure is performed in the vessels bifurcation (aorta and vena cava), at level L4–L5 the ligature of the lumbar ascending vein is the key point to allow appropriate retraction of the vessels. In some difficult cases the use of dedicated implants allows prosthesis insertion without extensive exposure by the use of an oblique implant. The disc preparation is crucial with a good posterior release. Insertion of the prosthesis is guided with instruments according to the type of fixation (keel or pikes). To optimise the implant positioning, navigation guidance is a useful tool as any offset of the prosthesis can induce a bad mechanical load transmission. Patient selection remains the key for good clinical outcomes.
Lumbar dynamic fixation is a subspecialty of joint surgery as practiced for years in peripheral articulations. It is used to surgically treat pain caused by lumbar degenerative lesions while preserving anatomical integrity and function. Technically, the concept is based on two options: improvement of intervertebral kinematics and unloading of the discs and facet joints. Its justification lies in finding an alternative to arthrodesis 1 and total disc replacement 2, especially for young and active adults.
Most imageless navigation systems for computer-assisted (CAS) total hip arthroplasty (THA) aim at orientating the cup with regard to the anterior pelvic plane (APP). However, these systems have some limitations: 1) the adequate position is not well defined to prevent impingement and dislocation; 2) dynamic variation of the APP according to activities (sitting, climbing stairs, etc.) are not integrated in determining the adequate orientation; 3) intraoperative assessment of the APP is not reliable with conventional tools, requiring ultrasound or two-stage identification. To address these issues, we developed an imageless CAS system without using APP, based on a kinematic approach of the hip joint. This system does not use the APP as the reference plane to orient the cup. The systemhelps the surgeon to orient the cup in relation to the cone describing the hip joint range of motion. The purpose of this study was to detail the technique and to analyze preliminary results.
Degenerative disc disease at some stage requires surgical treatment to improve the pain situation. As opposed to fusion technologies, which bring immediate pain relief but that will again develop over the next years due to adjacent level disease, motion-sparing devices appear to avoid this condition. The ProDisc-L is a ball and socket design with a semi-constrained biomechanical concept implanted to replace the intervertebral disc. The surgical procedure has a minimal learning curve and a low complication rate, in treatment of low back pain. Long-term results in terms of radiological data, clinical data, and subjective scores like VAS, ODI, SF-36 show high patient satisfaction and indicate an equal or sometimes superior treatment option over fusion procedures.
The author describes the use of a CT-free navigation system equipped with a software, specifically designed to improve the implantation of a modular-neck anatomic cementless stem and acetabular cup for Total Hip Replacement (THR). When comparing the anatomic parameters measured intraoperatively with the native hip and the prosthetic hip, it appears that the use of the modular-neck allows a better approximation of the native hip lateralization and cranio-podal lowering. Cost and additional time might very well be compensated by the significant outlier reduction. For other technologies (CT-based, Imageless, and virtual fluoroscopy), the average operative time is 20–30 min longer (on the average) as compared to conventional procedure. The image-free systems are not able to navigate dysplastic and revision cases. The CT-based navigation systems are more accurate than imageless navigation for the insertion of the acetabular component in THR, but necessitate preoperative CT-image acquisition. Virtual fluoroscopy is able to navigate hips where CT or CT less images are poor (as in revision THR) and in cases of previous hip fusion (where routine CT registration or point-clouds methods are not possible). Virtual fluoroscopy does not necessitate preoperative CT and planning, but the system has the disadvantage that the procedure is disrupted by the use of fluoroscopy during surgery. Patients with dysplastic hips, especially when osteotomies of the proximal part of the femur have been performed, have significant improvement in function with the use of custom made THR.
