Anatomical references for tibial sagittal alignment in total knee arthroplasty: a comparison of three anatomical axes based on 3D reconstructed CT images.

BACKGROUND: This study was designed to analyze three tibial axis reference lines including the anterior tibial cortex (ATC) line, the fibular line (FL), and the anatomical axis of tibia (AAT) line, to determine which line most closely parallels the mechanical axis (MA) of the tibia in the sagittal plane. The clinical relevance of the study is that through finding a reliable landmark on the leg, a surgeon may minimize posterior tibial slope measurement errors thereby and improving the technique for assuring proper alignment of total knee arthroplasty. METHODS: The material for this study included CT scans of the tibia from 85 consecutive patients and 168 knees (78 without osteoarthritis (OA) and 90 knees with OA). Measurements of the angles between the tibial mechanical axis and each of three reference lines in the sagittal plane were carried out using 3D imaging software. RESULTS: Mean angles of 168 knees were as follows: aMT (3.96±0.85)°, aMF (0.70±0.58)°, and aMA (1.40±0.66)°, (aMT: an angle between MA and ATC, aMF: an angle between MA and FL, aMA: an angle between MA and AAT. All abovementioned angles were measured in the sagittal plane of tibia) and the aMF was significantly smaller than the others (P < 0.0001). The mean value of the medial tibial slope angle vs. the MA was (9.19±3.97)°, and this was significantly larger than the mean lateral slope angle of (6.62±4.23)° (P < 0.0001). The difference between aMF without OA and with OA was not statistically significant (P = 0.5015) and the association between the aMT and aMA was strong (r = 0.82, P < 0.01). CONCLUSIONS: FL was more closely parallel to the MA of tibia, and more showed less variation between OA and non- OA controls than ATC and AAT lines. Furthermore, the amount of posterior slope in medial plateau was greater than that in lateral plateau. The findings of this analysis suggest that when using the anterior tibial cortex line as is commonly done with extramedullary tibial resection guides, the tibial resection should be sloped approximately four degrees more posteriorly.

Novel articulating medullary-sparing spacer for the treatment of infectious hip arthritis.

Two-stage total hip arthroplasty (THA) is considered a safe choice for the treatment of primary infectious arthritis of the hip. In cases where the proximal portion of the femur is intact without infection, the use of a spacer with a femoral stem during the interim would disturb the normal femoral medullary cavity. The authors report the technical procedure and outcomes of cases using a novel medullary sparing, antibiotic-loaded hip spacer for the treatment of hip infections.Five consecutive patients (5 hips) with infectious arthritis of the hip were treated in a 2-stage approach using an intraoperatively made medullary-sparing hip spacer. During the first-stage THA, after thorough debridement of potentially infected and necrotic soft tissues, the spacer was inserted into the femoral neck and fixed without opening the femoral canal. Antibiotics were administered for at least 6 weeks and were continued until the infection was controlled clinically, after which the second-stage THA was completed.Infection was eradicated in all 5 hips. Average follow-up was 39.6 months (range, 30-59 months). At most recent follow-up, no recurrence of infection was observed. No specific complications were associated with the use of this novel spacer. Average Harris Hip Score improved from 35.2 (range, 28-43) before the first-stage THA to 61.6 (range, 54-71) between the 2 stages and to 93.6 (range, 89-99) at final follow-up. All patients ambulated with the aid of crutches during the interim period.

[Cementless total hip arthroplasty for the management of advanced tuberculous coxitis].

OBJECTIVE: The question of whether a total joint arthroplasty should be attempted in a patient with a current or previous infection of tuberculosis continues to arouse controversy. The aim of this report was to evaluate the clinical outcomes of cementless total hip arthroplasty for the treatment of advanced tuberculosis of hip. METHODS: A total of 14 patients with advanced tuberculosis of hip treated by cementless total hip arthroplasty were retrospectively analyzed. For the patients with a definite diagnosis of tuberculosis and elevated levels of CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) before surgery, preoperative antituberculous medications were prescribed for at least 2 weeks. The inflamed soft tissues and destroyed bones were completely curetted out at the time of operation. Twelve of 14 patients received one-stage cementless total hip arthroplasty after a thorough debridement. For the remaining 2 patients, two-stage strategy was taken with cement articulating spacer implanted after a thorough debridement and followed by cementless total hip arthroplasty at 6-8 months later. All patients were prescribed antituberculous medications postoperatively for the first 6 months. RESULTS: The mean Harris Hip Score (HHS) was 36 preoperatively and 87 at the last follow-up. Within an average follow-up period of 49 months (range: 27 - 77), only one patient had reactivation of tuberculosis 7 months after primary THA (total hip arthroplasty) and received resection arthroplasty. Another 13 patients had no reactivation of tuberculosis and revealed stability by bone ingrowth on both socket and femoral stem. CONCLUSION: Cementless total hip arthroplasty is a safe and effective procedure for advanced tuberculosis of hip. With a thorough debridement followed by a complete course of antituberculous chemotherapy, active tuberculous infection should not be considered a contraindication for THA. In patients whose diagnosis of tuberculosis is confirmed intraoperatively and with no preoperative antituberculous chemotherapy, or in those a thorough debridement can not be achieved, a two-stage surgery may be considered.

[Cementless two-staged total hip arthroplasty for chronic periprosthetic infection].

OBJECTIVE: To determine the clinical outcomes of two-staged cementless revision arthroplasty for the treatment of deep periprosthetic infection after total hip arthroplasty. METHODS: Twenty-three patients with deep periprosthetic infection treated with a standard protocol of two-staged cementless revision hip arthroplasty were enrolled in this study. There were 9 male patients and 14 female patients with an average age of 64 years (range, 52-78 years). In all cases, antibiotics-loaded cement spacers were implanted after removal of all the prosthetic components and thorough debridements had been done. All patients had a minimum of 2 weeks of intravenous antibiotics followed by 4 weeks of oral antibiotics after implant removal. After a mean interval of 6.7 months (3-28 months), revision arthroplasties were carried out with cementless femoral components followed by 2 weeks of intravenous antibiotics and 4 weeks of oral antibiotics. RESULTS: The mean follow-up period was (4.3±3.5) years. There were 2 cases of recurrent infections in this study. Intraoperative periprosthetic fractures were observed in 3 patients. One patient had dislocation of the implanted spacer during the interval period and 2 patients had hip dislocation after reimplantation. Mild subsidence of femoral component occurred in 1 patient. There were no cases of loosening of femoral components and cementless acetabular components in patients without infection recurrence. The Harris hip score increased from a preoperative mean of 36±13 to 85±13 at 12 months after reimplantation. CONCLUSIONS: Using cementless prostheses in two-staged revisions of hip periprosthetic infections can provide low rate of infection recurrence and good implant stability, but cautions must be taken when treating patients with infection caused by multidrug-resistant organisms.