Two-stage revision total hip arthroplasty for periprosthetic infections using antibiotic-impregnated cement spacers of various types and materials.

Antibiotic-impregnated hip cement spacers of various types and materials have been used in the treatment of periprosthetic hip infections. We developed a handmade spacer by using polymethylmethacrylate (PMMA) and/or α -tricalcium phosphate ( α -TCP). In this study, we retrospectively reviewed the surgical outcomes in 36 consecutive patients treated with 2-stage revision total hip arthroplasty by using our antibiotic-impregnated hip cement spacers. We aimed to analyze the infection control and reinfection rates after revision surgery. Moreover, we analyzed the possible predictors of postoperative reinfection. After exclusion of 1 patient who died immediately after the first-stage surgery, infection was controlled in 33 of the 36 hips (success rate, 91.7%). Two of these 33 hips underwent resection arthroplasty. Of the 36 hips that had been treated with the antibiotic-cement spacer, 31 hips (86.1%) were eligible for the second-stage prosthesis re-implantation. The 31 protocol hip joints of patients followed up for >6 months (mean, 48.6 months). Ten of these 31 hips (32.3%) became reinfected. No possible predictor examined differed significantly between the reinfection-positive and reinfection-negative groups. However, spacers consisting of PMMA cement alone were associated with the highest risk of reinfection. Therefore, α -TCP-containing antibiotic-impregnated hip cement spacers might decrease the reinfection rate in patients undergoing re-implantation.

Long-term antibacterial activity of vancomycin from calcium phosphate cement in vivo.

BACKGROUND: Periprosthetic joint infection is a major complication of total joint arthroplasty, with treatment requiring a two-stage exchange procedure and 6 weeks of systemic antibiotics. However, depending on the infection site, intravenous delivery of antibiotics like vancomycin (VCM) can have poor tissue transferability, thus reducing their therapeutic effect. OBJECTIVE: This study demonstrates the 24-week in vivo release profile and antibacterial activity of VCM from calcium phosphate cement impregnated with VCM (CPC/VCM) and compares them with those from polymethylmethacrylate impregnated with VCM (PMMA/VCM). METHODS: Rats were implanted with the test specimens between the fascia and quadriceps. After implantation for 24 weeks, the test specimens were removed and residual VCM was extracted to calculate the concentration of VCM released into rat tissues. We also examined the antibacterial activity of releasable VCM from the removed test specimens by placing them directly onto the surface of agar. RESULTS: CPC/VCM released greater concentrations of VCM for a longer period of time within the 24 weeks than PMMA/VCM. Moreover, CPC/VCM released 1.4 to 26.1-fold more VCM than PMMA/VCM. Using Staphylococcus aureus, antibacterial activity was logarithmically correlated with VCM concentration across the entire concentration range tested (12.5-800 µg/mL). While the area within which inhibition was observed-the inhibition zone-for both CPC/VCM and PMMA/VCM formed and gradually shrank with time after implantation, that for CPC/VCM was significantly larger than that for PMMA/VCM in each week after implantation. CONCLUSION: CPC/VCM releases greater amounts of VCM with antibacterial activity for longer periods of time than PMMA/VCM, suggesting that CPC is effective for facilitating the release of antibiotics for local action in patients with established postoperative infection.

Arthroscopic Superior Capsule Reconstruction for Cuff Tear Arthropathy (Hamada Grade 5): A Case Report.

CASE: We performed arthroscopic superior capsule reconstruction (ASCR) for cuff tear arthropathy (CTA) with humeral head deformity. A 62-year-old man presented with severely limited shoulder motion and recalcitrant omalgia. He had a history of dental implant removal due to metal allergy, and his Constant score was 21 points. We diagnosed CTA with Hamada classification grade 5 and performed ASCR to avoid allergic reactions. Severe night pain improved within 1 week of ASCR, and his Constant score after 2 years was 74 points. CONCLUSION: ASCR may be an effective alternative treatment for patients with CTA with humeral head deformity.

Polyglycolic acid-collagen tube combined with collagen-binding basic fibroblast growth factor accelerates gait recovery in a rat sciatic nerve critical-size defect model.

Several nerve conduits have been investigated for their potential as alternative sources of autografts for bridging neural gaps. However, autologous nerve transplants remain the most effective for nerve repair. We examined clinically approved nerve conduits containing collagen and polyglycolic acid (PGA-c) combined with collagen-binding basic fibroblast growth factor (bFGF) containing a polycystic kidney disease (PKD) domain and collagen binding domain (CBD) (bFGF-PKD-CBD) in a rat 15-mm sciatic nerve critical-size defect model. The treatment groups were: PGA-c immersed in phosphate-buffered saline (PBS) (PGA-c/PBS group), bFGF (PGA-c/bFGF group), or bFGF-PKD-CBD (PGA-c/bFGF-PKD-CBD group), and no treatment (Defect group). Gait and histological analyses were performed. Four weeks after treatment, the recovery rate of the paw print area was significantly greater in the PGA-c/bFGFPKD-CBD group than the PGA-c/PBS and PGA-c/bFGF groups. Mean intensity of paw prints was significantly greater in the PGA-c/bFGF-PKD-CBD group than the PGA-c/PBS and Defect groups. Swing time was significantly greater in the PGA-c/PBS, PGA-c/bFGF, and PGA-c/bFGF-PKD-CBD groups than the Defect group. At 8 weeks, all three parameters were significantly greater in the PGA-c/PBS, PGA-c/bFGF, and PGA-c/bFGF-PKD-CBD groups than the Defect group. Regenerated myelinated fibers were observed in 7/8 (87.5%) rats in the PGA-c/bFGF-PKD-CBD group after 8 weeks, and in 1/8 (12.5%) and 3/8 (37.5%) rats in the PGA-c/PBS and PGA-c/bFGF groups, respectively. PGA-c/bFGF-PKD-CBD composites may be promising biomaterials for promoting functional recovery of long-distance peripheral nerve defects in clinical practice.

Regression of Retro-odontoid Pseudotumor Using External Orthosis without Atlantoaxial Fusion: A Case Report.

CASE: We treated an 87-year-old woman with noninflammatory retro-odontoid pseudotumor induced by atlantoaxial instability (AAI) using only a Philadelphia collar. Because of perioperative risk factors, fusion surgery was canceled; nevertheless, the neurological symptoms improved gradually. After 11 months of nonoperative treatment, the follow-up magnetic resonance imaging demonstrated that the pseudotumor's size was obviously diminished. Orthosis was applied for 2 years, and after its removal, the pseudotumor's size remained the same at the final 7-year follow-up. CONCLUSIONS: External orthosis is one treatment option for pseudotumor with AAI, especially in patients with significant comorbidities for whom surgical procedures are relatively contraindicated.

Double-layered antibiotic-loaded cement spacer as a novel alternative for managing periprosthetic joint infection: an in vitro study.

BACKGROUND: Previous studies comparing antibiotic-loaded calcium phosphate cement to polymethylmethacrylate cement reported that although the former has higher elution volumes over a longer period, it is mechanically weak when used alone. To counter this problem, a double-layered antibiotic-loaded cement spacer in which calcium phosphate cement is coated with polymethylmethacrylate cement was created. METHODS: In this study, we compared the double-layered spacer to the polymethylmethacrylate cement spacer in terms of eluent antibiotic concentration, bioactivity against methicillin-resistant Staphylococcus aureus, and mechanical strength. Double-layered and polymethylmethacrylate cement spacers that were loaded with vancomycin (VCM) were prepared and immersed in phosphate buffer for 84 days. To facilitate VCM elution from calcium phosphate cores in double-layered spacers, we also drilled multiple holes into the calcium phosphate layer from the spacer surface. RESULTS: We found that VCM concentrations in double-layered spacer eluents were higher than those in polymethylmethacrylate cement spacer eluents. The double-layered spacer also had higher bioactivity than the polymethylmethacrylate cement spacer. Although the polymethylmethacrylate cement spacer eluent lost the ability to inhibit bacterial growth on day 56, the double-layered spacer eluent maintained this ability for the duration of our study. Finally, the double-layered spacer retained high mechanical strength throughout the study period. CONCLUSIONS: The beneficial biomechanical and drug-eluting properties of the double-layered spacer might qualify it to serve as a promising biomaterial that could be used for managing periprosthetic joint infections.

In Vivo Release of Vancomycin from Calcium Phosphate Cement.

Calcium phosphate cement (CPC) has good release efficiency and has therefore been used as a drug delivery system for postoperative infection. The release profile of CPC has mainly been evaluated by in vitro studies, which are carried out by immersing test specimens in a relatively large amount of solvent. However, it remains unclear whether antibiotic-impregnated CPC has sufficient clinical effects and release in vivo. We examined the in vivo release profile of CPC impregnated with vancomycin (VCM) and compared this with that of polymethylmethacrylate (PMMA) cement. To evaluate the release profile in vitro, the test specimens were immersed in 10 mL sterile phosphate-buffered saline per gram of test specimen and incubated at 37°C for 56 days in triplicate. For in vivo experiments, the test specimens were implanted between the fascia and muscle of the femur of rats. Residual VCM was extracted from the removed test specimens to determine the amount of VCM released into rat tissues. CPC released more VCM over a longer duration than PMMA in vitro. Released levels of VCM from CPC/VCM in vivo were 3.4-fold, 5.0-fold, and 8.6-fold greater on days 1, 7, and 28, respectively, than those released on the corresponding days from PMMA/VCM and were drastically greater on day 56 due to inefficient release from PMMA/VCM. The amount of VCM released from CPC and PMMA was much higher than the minimum inhibitory concentration (1.56 µg) and lower than the detection limit, respectively. Our findings suggest that CPC is a suitable material for releasing antibiotics for local action against established postoperative infection.

Triclosan-coated sutures reduce wound infections after spinal surgery: a retrospective, nonrandomized, clinical study.

BACKGROUND CONTEXT: Surgical site infection (SSI) is a serious postoperative complication. The incidence of SSIs is lower in clean orthopedic surgery than in other fields, but it is higher after spinal surgery, reaching 4.15% in high-risk patients. Several studies reported that triclosan-coated polyglactin 910 sutures (Vicryl Plus; Ethicon, Inc., Somerville, NJ, USA) significantly reduced the infection rate in the general surgical, neurosurgical, and thoracic surgical fields. However, there have been no studies on the effects of such coated sutures on the incidence of SSIs in orthopedics. PURPOSE: To compare the incidence of wound infections after spinal surgery using triclosan-coated suture materials with that of noncoated ones. STUDY DESIGN/SETTING: A retrospective, nonrandomized, and clinical study. PATIENT SAMPLE: From May 2010 to April 2012, 405 patients underwent a spinal surgical procedure in the Department of Orthopedic Surgery of two university hospitals. OUTCOME MEASURES: The primary outcome was the number of wound infections and dehiscences. METHODS: Two hundred five patients had a conventional wound closure with polyglactin 910 suture (Vicryl) between May 2010 and April 2011 (Time Period 1 [TP1]), and 200 patients underwent wound closure with triclosan-coated polyglactin 910 suture (Vicryl Plus) between May 2011 and April 2012 (TP2). Statistical comparisons of wound infections, dehiscence, and risk factors for poor wound healing or infection were performed. None of the authors has any conflict of interest associated with this study. RESULTS: There were two cases of wound dehiscence in TP1 and one in TP2 (p=.509). Using noncoated sutures in TP1, eight patients (3.90%) had wound infections, whereas one patient (0.50%) had wound infections in TP2 (using triclosan-coated sutures); the difference was significant (p=.020). CONCLUSIONS: The use of triclosan-coated polyglactin 910 sutures instead of polyglactin 910 sutures may reduce the number of wound infections after spinal surgery.

Severe cervical kyphotic deformity caused by postural disorders in a child with schizophrenia.

BACKGROUND CONTEXT: Although severe cervical kyphotic deformity results from a number of causes, the psychiatric disease itself did not play a metabolic role in the development of the deformity. However, we diagnosed a case of cervical deformity caused by postural disorders associated with schizophrenia. PURPOSE: The purpose of this case report is to describe a rare episode in a schizophrenic patient with a fixed cervical flexion deformity caused by postural disorders. STUDY DESIGN: A case report. PATIENT SAMPLE: An 18-year-old woman with a history of schizophrenia and a persistent behavioral cervical flexion posture presented for evaluation. At the initial examination, a significant fixed cervical flexion measuring 100° was noted. Her chin was in contact with her manubrium, and left scars developed on both her chin and manubrium. She had hyperreflexia in all extremities but no further neurologic deficits, although her initial magnetic resonance imaging (MRI) indicated multilevel cervical cord compression. METHODS: She was initially treated conservatively but had a progression in fixed cervical flexion positioning. She complained of a persistent inability to ambulate within the community, as she was unable to bring her head into a neutral position to be able to see objects in her path. She also complained of inability to drink from a water bottle as she had difficulty depressing her mandible. The patient and her family requested a surgical correction. Although she had no significant clinical neurologic deficit, she did have significant MRI findings and limitation of functional activities. We felt her limitations were significant enough to warrant surgical correction. RESULTS: A combined anterior and posterior procedure was performed resulting in an improved cervical head posture. She was able to return to community activities and resume drinking from a water bottle. CONCLUSIONS: Although this technique has been well described previously, this is the first report of a rare episode in a schizophrenic patient with severe cervical kyphosis deformity because of a constant neck flexion posture.

Hammering sound frequency analysis and prevention of intraoperative periprosthetic fractures during total hip arthroplasty.

Adequate fixation at the time of cementless stem implantation depends on the operator's experience. An objective evaluation method to determine whether the stem has been appropriately implanted may be helpful. We studied the relationship between the hammering sound frequency during stem implantation and internal stress in a femoral model, and evaluated the possible usefulness of hammering sound frequency analysis for preventing intraoperative fracture. Three types of cementless stem (BiCONTACT®, SL-PLUS®, and AI-Hip®) were used. Surgeons performed stem insertion using a procedure similar to that employed in a routine operation. Stress was estimated by finite element analysis, the hammering force was measured, and frequency analysis of hammering sound data obtained using a microphone. Finite element analysis showed a decrease in the hammering sound frequency with an increase in the estimated maximum stress. When a decrease in frequency was observed, adequate hammering had occurred, and the continuation of hammering risked fracture. Based on the relationship between stress and frequency, the evaluation of changes in frequency may be useful for preventing the development of intraoperative fractures. Using our method, when a decrease in frequency is observed, the hammering force should be reduced. Hammering sound frequency analysis may allow the prediction of bone fractures that can be visually confirmed, and may be a useful objective evaluation method for the prevention of intraoperative periprosthetic fractures during stem insertion.