The main challenges in hip arthrodesis takedown include the decision to perform fusion takedown and the technical difficulties of doing so. In addition to the functional disadvantages of hip fusion, the long-term effects of hip arthrodesis include low back pain and in some cases ipsilateral knee pain. Indications for fusion conversion to THA include arthrodesis malposition, pseudoarthrosis, and ipsilateral knee, low back, contralateral hip problems, and functional disadvantages of ipsilateral hip fusion. When deciding whether or not to take down fusion, consider the severity of the current problem, risks of takedown and likely benefits of takedown. Best results of fusion takedown occur if abductor function is likely to be present. If the abductors are not likely to function well, dearthrodesis may still help, but the patient will have a profound Trendelenburg or Duchenne gait and risk of hip instability will be higher. Abductor assessment can be performed by determining if the abductors contract on physical exam and determining if the previous form of fusion spared the abductors and greater trochanter. EMG and MRI also can be performed to assess the abductors, but value in this setting is unproven. Before dearthrodesis establish realistic expectations: most patients will gain hip motion—but not normal motion, most will see improvement in back/knee pain, but many will become cane-dependent for life. The main technical issues to overcome involve exposure, femoral neck osteotomy, acetabular preparation, and femoral fixation. Exposure can be conventional posterior, anterolateral or direct anterior with an in-situ femoral neck cut. In complex cases, a transtrochanteric approach is often helpful. The in-situ neck cut is facilitated by fluoroscopy or intraoperative radiograph to make sure the cut is at the correct level and at the correct angle. Be careful not to angle into the pelvis with the cut. Acetabular preparation is more complex because anatomic landmarks often are absent or distorted. Try to find landmarks including ischium, ilium, teardrop, and fovea. Confirm location with fluoroscopy as reaming commences and during reaming. Depth of reaming can be improved by using the fovea (if present) and teardrop on fluoroscopy. Cup fixation is usually an uncemented cup, fixed with multiple screws because bone quality typically is compromised. Femoral fixation is at the surgeon's discretion, recognizing the proximal bone may be distorted in some cases. Postoperative management includes protected weight bearing as needed and heterotopic bone prophylaxis in selected patients

Introduction. Hip Arthrodesis had been considered as a useful surgical option in young adult patient with high activity demands suffering from osteoarthritis of the hip. Although the procedure surely eliminates pain of the hip joint, it can also cause disorders of the adjacent joints in addition to the complete loss of motion, might consequently deteriorate the activity of daily living. The purpose of this retrospective study was to investigate the efficacy and drawback of hip arthrodesis, focusing on the effect of this procedure on the adjacent joints. Materials and Methods. From 1976 to 1989, 29 hip arthrodesis were performed and 22 hips were followed up (1 died, 6 lost). Disorders led to arthrodesis were septic arthritis (1 hip), post-traumatic (1), osteonecrosis (1), primary osteoarthritis (3), and secondary osteoarthritis due to DDH (16). The average age at surgery was 38 years (range, 19–53 years, 6 men and 16 women). Hip arthrodesis was indicated for young active adults with end stage osteoarthritis, who had normal or mild osteoarthritis in contralateral hip and needed physical labor. The hip was positioned in 30 degrees of flexion, 0 to 5 degree of external rotation, and 0 to 5 degree of abduction. Clinical and radiographic assessment was done for these patients. The clinical follow-up consisted of questionnaire which assessed ability of typical Japanese daily living movement and patient's satisfaction. The condition of the adjacent joints was evaluated clinically and radiographically. Results. After an average follow-up of 22 years (range15-28), no patients complained of pain in the fused hip joint. On the other hand, pain in the adjacent joints was seen frequently. Seventeen (77%) of 22 patients had low back pain and one of these patients, who had severe low back pain, required conversion of arthrodesis to THA. Ten patients (45%) had contralateral hip pain and 8 (36%) of whom subsequently needed THA. All patients who required THA had early stage osteoarthritis when they underwent arthrodesis. Ten patients (45%) had knee pain (5 in the ipsilateral and 5 in the contralateral knee). Radiographic progression of osteoarthritis in adjacent joints was also seen frequently, namely, 9 in lumbar spine, 11 in contralateral hip, 6 in ipsilateral and 6 in contralateral knee. Although pain in the involved hip disappeared, activity of daily living was severely deteriorated (impossible to clip nail: 88%, ride a bicycle: 94%, use a Japanese toilet: 75%, sit in Japanese style: 50%). As a result, only 4 patients (18%) were satisfied with the hip arthrodesis. Discussion. The satisfaction of hip arthrodesis was unexpectedly poor despite of pain relief of involved hip joint. One of essential reasons was activity of daily living in Japanese style, which requires relatively deep flexion in hip and knee. Compensation of limited movement in hip might cause pain and progression of osteoarthritic change in adjacent joints. Another vital reason was that we indicated this procedure for bilateral DDH case whose contralateral hip had early stage osteoarthritis, ended up with THA in most cases

Introduction. Management of the sequelae of arthritis of the hip joint has changed over time. Total joint replacement has gained popularity due to retained mobility and stability. In the high demand paediatric and adolescent population problems are encountered with longevity of the procedure. Hip arthrodesis is a useful alternative procedure that sacrifices mobility of the joint to achieve pain relief and restores function. Several surgical techniques have been described to achieve hip fusion. We describe a technique that achieves concentric bone surfaces with hip resurfacing reamers. Maximum bone is preserved to maintain leg length. Trans-articular compression is achieved with cannulated screw fixation. Subtrochanteric de-functioning osteotomy completes the procedure to protect the fusion site and control the position of the limb. Our optimal position of fusion was 30 degrees of flexion, neutral to 5 degrees of abduction and neutral to 10 degrees of external rotation. Methods. Fourteen patients (8 female) treated by hip arthrodesis over a two-year period are reviewed in terms of clinical and radiological outcome in the short term. Their mean age at hip fusion was 11 years (6–18). The etiology included TB (6 cases), staphylococcal infection (2), non-specific arthritis (3), Perthe's (1), chondrolysis (1) and avascular necrosis following trauma (1). Results. Fusion was achieved in 12/14 patients. All patients in whom fusion was achieved had relief of pain and returned to their normal activities. Conclusion. We believe hip arthrodesis performed in the correct patient is a good procedure to preserve function and relieve pain. The procedure is technically demanding and careful follow-up to ensure optimal positioning and solid fusion is essential to ensure good results. NO DISCLOSURES

We report an intertrochanteric fracture in a patient who had undergone hip arthrodesis 30 years previously. A 53-year-old man was injured in a head-on car crash and was referred to our hospital for treatment. Plain radiographs showed an intertrochanteric fracture of the right proximal femur and deformity of the right hip joint. He had undergone hip arthrodesis surgery 30 years previously at another hospital. Computed tomography scan showed marked atrophy of the gluteus and iliopsoas muscles. He preferred undergoing total hip arthroplasty (THA) to internal fixation. THA was performed using the anterolateral approach with the patient in the supine position as he had undergone hip arthrodesis through the Smith–Petersen approach, and we were concerned about damaging the gluteus muscle and dislocation if we took the posterolateral approach. The femoral head was removed using curved chisels under fluoroscopy. A cementless THA (J Taper stem, Aquala polyethylene liner; Kyocera Medical Corporation, Osaka, Japan) was inserted and fixed appropriately. Full weight-bearing using a walking frame was allowed 2 weeks after the surgery. Six months after the operation, he was able to walk independently and had good range of movement of the hip joint but continued to have weakness in the abductor muscles. Very few cases of proximal femur fracture in a previously arthrodesed hip have been reported. Manzotti et al. reported a similar case but they performed open reduction and internal fixation. No previous reports in the literature describe THA for intertrochanteric fracture in an arthrodesed hip. The conversion of an arthrodesed hip to THA is technically challenging. It has a high risk of complications such as nerve injuries and hip instability. We were able to treat the patient successfully, but surgeons should carefully decide the treatment method depending on the case

The main challenges in hip arthrodesis takedown include the decision to perform fusion takedown and the technical difficulties of doing so. In addition to the functional disadvantages of hip fusion, the long-term effects of hip arthrodesis include low back pain and in some cases ipsilateral knee pain. Indications for fusion conversion to THA include arthrodesis malposition, pseudoarthrosis, and ipsilateral knee, low back, contralateral hip problems, and functional disadvantages of ipsilateral hip fusion. When deciding whether or not to take down a fusion, consider the severity of the current problem, risks of takedown and likely benefits of takedown. Best results of fusion takedown occur if abductor function is likely to be present. If the abductors are not likely to function well, dearthrodesis may still help, but the patient will have a profound Trendelenburg or Duchenne gait and risk of hip instability will be higher. Abductor assessment can be performed by determining if the abductors contract on physical exam and determining if the previous form of fusion spared the abductors and greater trochanter. EMG and MRI also can be performed to assess the abductors, but value in this setting is unproven. Before dearthrodesis establish realistic expectations: most patients will gain hip motion—but not normal motion, most will see improvement in back/knee pain, but many will become cane-dependent for life. The main technical issues to overcome involve exposure, femoral neck osteotomy, acetabular preparation, and femoral fixation. Exposure can be conventional posterior, anterolateral or direct anterior with an in situ femoral neck cut. In complex cases, a transtrochanteric approach is often helpful. The in situ neck cut is facilitated by fluoroscopy or intra-operative radiograph to make sure the cut is at the correct level and at the correct angle. Be careful not to angle into the pelvis with the cut. Acetabular preparation is more complex because anatomic landmarks often are absent or distorted. Try to find landmarks including ischium, ilium, teardrop, and fovea. Confirm location with fluoroscopy as reaming commences and during reaming. Depth of reaming can be improved by using the fovea (if present) and teardrop on fluoroscopy. Cup fixation is usually an uncemented cup, fixed with multiple screws because bone quality typically is compromised. Femoral fixation is at the surgeon's discretion, recognizing the proximal bone may be distorted in some cases. Post-operative management includes protected weight bearing as needed and heterotopic bone prophylaxis in selected patients

Patients with longstanding hip fusion are predisposed to symptomatic degenerative changes of the lumbar spine, ipsilateral knee and contralateral hip. In such patients, conversion of hip arthrodesis to hip replacement can provide relief of such symptoms. However, this is a technically demanding procedure associated with higher complication and failure rates than routine total hip replacement. The aim of this study was to determine the early functional results and complications in patients undergoing hip fusion conversion to total hip replacement, performed or supervised by a single surgeon, using a standardised approach and uncemented implants. We hypothesised that a satisfactory functional improvement can be achieved in following conversion of hip fusion to hip replacement. Eighteen hip fusions were converted to total hip replacements. A constrained acetabular liner was used in 3 hips. Mean follow up was 5 years (2 to 15 years). Two (11%) hips failed, requiring revision surgery and two patients (11%) had injury to the peroneal nerve. Heterotopic ossification developed in 7 (39%) hips, in one case resulting in joint ankylosis. No hips dislocated. Conversion of hip fusion to hip replacement carries an increased risk of heterotopic ossification and neurological injury. We advise prophylaxis against heterotopic ossification. When there is concern about hip stability we suggest that the use of a constrained acetabular liner is considered. Despite the potential for complications, this procedure had a high success rate and was effective in restoring hip function

Some DEFINITIONS are necessary: “STEMS” refers to “intramedullary stem extensions”, which may be of a variety of lengths and diameters, fixed with cement, porous coating or press fit alone and which may be modular or an inherent part of the prosthesis. The standard extension keel on the tibia does not qualify as a “stem (extension)”. COMPLEX implies multiple variables acting on the end result of the arthroplasty with the capability of inducing failure, as well as necessary variations to the standard surgical technique. A lesser degree of predictability is implied. More specifically, the elements usually found in an arthritic knee and used for the arthroplasty are missing, so that cases of COMPLEX primary TKA include: Soft tissue coverage-(not relevant here), Extensor mechanism deficiency-patellectomy, Severe deformity, Extra-articular deformity, Instability: Varus valgus, Instability: Plane of motion, Instability: Old PCL rupture, Dislocated patella, Stiffness, Medical conditions: Neuromuscular disorder, Ipsilateral arthroplasty, Prior incisions, Fixation hardware, Osteopenia, Ipsilateral hip arthrodesis, Ipsilateral below knee amputation, etc. Complexity includes MORE than large deformity, i.e., success with large deformity does NOT mean success with constrained implants regardless of indication. In addition, the degree of constraint must be specified to be meaningful. NECESSARY presumably this means: “necessary to ensure durable fixation in the face of poor bone quality or more mechanically constrained” and SUFFICIENT suggests that stems, by themselves or in some shape of form, by themselves “will ensure success (specifically here) of fixation”. If we can start with the second proposal, that STEMS are SUFFICIENT for success the answer is: “NO”, many more aspects of surgical technique and implant design are required. Even if all other aspects of the technique are exemplary, some types of stems or techniques are inadequate, e.g., completely uncemented, short stem extensions. The answer to the first proposal is: “YES, in many cases”. The problem will be to determine which cases. There are philosophical analogies to this question that we already know the answer to. ANALOGY: Is a life-raft necessary on a boat? Yes, you may not use it, but it is considered necessary. Is a life-raft “sufficient” on a boat? No, other problems may occur. Are seat belts necessary? Are child seats necessary? The AAOS already has a position on child restraints, an analogous situation, where a party who cannot control their situation (anesthetised patient/ child) functions in the care of a responsible party. The objection may be argued in terms of cost saving by NOT using increased fixation. A useful analogy, (that would of course require specific analysis), is that of patellar resurfacing: universal resurfacing is cost-effective when considering the expense of even a small number of secondary resurfacings. Of course a complex arthroplasty that requires a revision procedure is far more expensive than secondary patellar resurfacing and so universal use of the enhanced fixation in the face of increased constraint makes sense. The human cost of revision surgery tips the balance irrefutably. DANGER-We must avoid the glib conclusion, often based on poor quality data, that constrained implants do not need additional intramedullary fixation (with stem extensions). When “complexity” is involved, complex analysis is appropriate to select the best course