Acetabular Insufficiency Fracture Following Prolonged Alendronate Use and the Failure of Total Hip Arthroplasty in “Frozen” Bone: Two Cases Report / 대한고관절학회지

Atypical insufficiency fracture of the femur following prolonged bisphosphonate use is well described. Regardless of the cause, insufficiency fracture of the acetabulum is extremely rare, and no reports have described insufficiency fractures of the acetabulum that are associated with prolonged bisphosphonate use. This report demonstrates the possibility of insufficiency fracture at the acetabulum following long-term alendronate use and the necessity of particular care in managing insufficiency fractures in “frozen” bone. We describe two cases of insufficiency fracture of the acetabulum following 6 years of alendronate use. Given the patients' medical histories and bone biopsy findings, these insufficiency fractures were thought to be attributable to alendronate use. One case involved the left hip and the presence of pelvic fractures on the opposite side. The patient was treated using cementless total hip arthroplasty (THA), which failed 1 year after surgery. The hip was revised with a massive bone graft and a supportive wire mesh. The other case was managed via THA with a Ganz reinforcement ring due to concerns regarding the use of a cementless implant.

Osteotomy around the Hip Joint

Hip joint preserving osteotomy surgery is the treatment of choice for young patients with early symptomatic structural abnormalities of the acetabulum and proximal femur. This is true even in the absence of severe secondary degenerative changes. These disorders can include hip instability from classic developmental dysplasia, post-traumatic acetabular dysplasia, hip impingement from retrotorsional acetabular deformities, or, rarely, post-traumatic problems. During the past 20 years, various techniques of acetabular and proximal femoral reorientation have evolved, making the procedure reliable, reproducible, and durable. In this report, the current indications and results of acetabular and proximal femoral osteotomies in patients with symptomatic acetabular structural problems will be discussed.

Pathologic Fracture in Radiation-induced Osteosarcoma Misdiagnosed as Delayed Femoral Neck Fracture / 대한정형외과학회잡지

Secondary osteosarcoma has a relatively higher incidence in middle aged persons than in children. Radiation-induced osteosarcoma occurs in approximately 1% of patients who have been treated with more than 2,500 cGy. The time interval from radiation to onset of secondary osteosarcoma is approximately 10 to 15 years. A 51-year-old female who have been treated with radiation for angiomyxoma was hospitalized due to right hip pain. She had a minor trauma 2 weeks prior to hospitalization. A day before hospitalization, she experienced a second trauma by fall, and then, severe hip pain developed. A radiograph of the patient showed femoral neck fracture with sclerotic change of fractured margin. We diagnosed the patient as having a neglected femoral neck fracture and treated it with closed reduction using cannulated screw fixation. At 6 months post-surgery, the patient had residual pain of the right hip and we could find overproduced callus at the fracture site. Through further evaluation, we diagnosed this as secondary osteosarcoma with pulmonary metastasis. We report this case to make a warning about a misdiagnosed osteosarcoma as a simple femoral neck fracture.

Revision Total Hip Arthroplasty Using Acetabular Reinforcement Ring: Midterm Follow-up Result

PURPOSE: To evaluate the clinical and radiographic outcomes of the revision total hip arthroplasty using the acetabular reinforcement ring. MATERIALS AND METHODS: Thirty-six acetabular revisions were performed in 36 patients with use of the reinforcement ring and structural or morselized allograft, between 1997 and 2005, in thirty-six patients. According to the AAOS classification, thirty-four cases of acetabular defects were Ttype III, and two were Ttype IV. Mean follow-up period after surgery was 7.2 years. RESULTS: The mean Harris hip score was 92.3, which was significantly increased compared with the preoperative score. (p<0.001). There were five failures: a case of aseptic loosening of Muller ring, two cases of infection (5.4%) and two cases of hip dislocation (5.4%). Graft incorporation and bone remodeling occurred successfully in all hips, but in the case of aseptic loosening in which the ring fixation had been inadequate at the time of surgery. The success rate was 91.7% with a mean follow-up of 7.2 years, if the cases of revision or loosening of the component were classified into failure cases. CONCLUSION: Patients treated with acetabular revision with three kinds of reinforcement ring had reconstitution of periacetabular bone stock as well as good clinical and radiographic results. For the good results, the secure implant fixation during the surgery should be confirmed and we should completely understand the characters of the each kinds of reinforcement rings.

Isolated Polyethylene Liner Exchange in a Revision Total Hip Arthroplasty

PURPOSE: To analyze the results of isolated exchange of polyethylene (PE) liners for treatment of wear and osteolysis around a well-fixed Harris-Galante (HG) cementless acetabular cup. MATERIALS AND METHODS: Thirty-three PE liner changes were performed without the removal of stably ingrown implants (33 hips of 32 patients). They were able to be followed for a mean period of 92 months. Clinically, the Harris hip score (HHS), pain evaluation, and complications were evaluated. Radiologically, the annual wear rate and the size of the osteolytic lesions were measured before the operation and the latest follow-up. The bone graft incorporation scale and the development of new osleolytic lesions were checked during the final follow-up. RESULTS: HHS improved to 89.3 at last follow-up. The size of the osteolysis was significantly reduced postoperatively. Bone graft incorporation scales were Grade I in 9 and Grade II in 14 cases. New osteolytic lesions have not developed at latest follow-up. As a complication, one case of dissociation of a liner and a periprosthetic fracture were noted. Annual wear rates during the same period were significantly reduced. There was no sign of alteration in stability of the PE liner. CONCLUSION: Exchange of a PE liner without removal of stable implants can be a good option for the treatment of wear and osteolysis around a stable cementless THA implant, even if the system has a weak locking mechanism, such as the HG cup. In these cases, under certain states with a higher risk of early failure in the locking mechanism, it would be better to select other revision procedures such as cup revision or cemented polyethylene liner fixation.

Revision Total Hip Arthroplasty Using a Fully Porous-Coated Long Stem: a Minimum 5 Years Follow up

PURPOSE: We wanted to evaluate the mid-term results of revision total hip arthroplasty using a fully porous-coated long stem. MATERIALS AND METHODS: A retrospective series of 20 hips in 19 patients who underwent stem revision with a fully porous-coated long stem were evaluated at a mean follow-up of 64.6 months. The causes of revision were aseptic loosening, periprosthetic fracture and infected arthroplasty. Four kinds of implants had previously been used and an additional bone graft procedure had been done in 17 cases. The Harris hip scores, thigh pain, limping and ROM were reported. Radiological changes of the radiolucent signs, subsidence, loosening and the stress shielding signs were evaluated. RESULTS: The Harris hip score improved from an average of 56.5 to 91.9 and the ROMs were satisfactory. The only case with persistent thigh pain showed stable bony ingrowth. No signs of subsidence or loosening of the stem was found in all the cases. There were 2 cases of periprosthetic fracture. None of the patients experienced re-revision surgery. CONCLUSION: The mid-term results of revision hip arthroplasty using a fully porous coated long stem have demonstrated that it provides a reliable initial fixation with a propensity for stable longevity. It is relatively easy for the techniques, and there is the opportunity to restore the bone stock by bone-grafting procedures with diaphyseal fixation and bypassing a bone defect. Yet alternative techniques may be required for the femur with extensive diaphyseal bone loss. There are some concerns about the technique and the possibility of making a crack in the femur during the operation, which will cause thigh pain at the follow-up. So, only by employing great caution when performing this technique can successful results be guaranteed.

A Comparative Study of the Navigated and Radiographic Measurements in Open and Closed Wedge High Tibial Osteotomy with Computer Assisted Surgery / 대한정형외과학회잡지

PURPOSE: We wanted to identify the difference of the measured values between a navigation system and radiographs when performing open and closed wedge high tibial osteotomy (HTO) under the control of a navigation system. MATERIALS AND METHODS: Thirty-two open wedge HTOs and 51 closed wedge HTOs were performed using a navigation system. The postoperative mechanical axis percent, which was planned on the navigation system, was 62%. The mechanical axis (MA) was measured before osteotomy and after fixation on the navigation system, and these were compared with the measured values from the radiographs. The difference of the postoperative MA between the navigation system and the radiographs was compared according to the type of HTO. The alteration of the tibial posterior slope angle was also compared. RESULTS: For the open wedge HTO, the mean MA after fixation was valgus 2.7degrees on the navigation system and the postoperative MA was valgus 4.0degrees on the radiograph. For the closed wedge HTO, the mean MA after fixation was valgus 3.5degrees on the navigation system and the postoperative MA was valgus 1.6degrees on the radiograph (p=0.000). The mean tibial posterior slope angle was increased by 5.3degrees after the open wedge HTO and it was decreased by 1.8degrees after closed wedge HTO (p=0.000). CONCLUSION: Performing HTO with a navigation system could increase the surgical accuracy because the navigation system checked the intraoperative correction angle in real time. Weight bearing makes a difference for the postoperative MA between the navigation system and radiographs. This should be taken into account, according to the type of HTO.

Acetabular Reconstruction with Impacted Morselized Allograft, Wire Mesh and Cemented Acetabular Cup in Severe Acetabular Bone Defect

PURPOSE: This study evaluated the clinical and radiographic results of an acetabular reconstruction with an impacted morselized allograft and wire mesh in revision total hip arthroplasty. MATERIALS AND METHODS: This study examined 21 cases of acetabular revisions involving 20 patients with a severe acetabular bone defect managed with an impacted morselized allograft, wire mesh and cemented acetabular cup between February 2000 and June 2003. The mean follow up period was 31.7 months. Clinically, the Harris hip score was evaluated. The radiographic parameters included bony incorporation between the host bone and allograft, the change in cup inclination, acetabular cup migration, radiolucency around the cup and loosening. RESULTS: The mean Harris hip score was improved from a preoperative 54.1 to 91.9 at the last follow up. Radiological incorporation between the host bone and allograft was achieved after an average 11.4 months after surgery. The mean change in cup inclination was 1.9 degrees, and the mean medial and superior migration was 3.93 mm and 4.41 mm respectively. The majority of these radiological changes occurred within 6 months after surgery. One case of Brooker grade I heterotopic ossification and one case of acetabular cup loosening was observed but there was no re-revision or complications, such as infection and dislocation. CONCLUSION: In a severe acetabular bone stock deficiency that cannot be reconstructed with a cementless acetabular cup, an acetabular reconstruction with an impacted morselized allograft, wire mesh and cemented acetabular cup showed good results in this short term follow up study.