Background

Irrigation and débridement (I&D), often with exchange of modular polyethylene components, is commonly used to treat acute periprosthetic infection (PPI) following total joint arthroplasty. Two-stage revision, the “Gold Standard” for PPIs' is more invasive, requires more resources, creating controversy over recommended initial treatment of PPIs. This study seeks to determine the success rate of an “intent to treat” approach utilizing I&Ds with progression to two stage revisions as required.

The senior author has treated a series of patients with subtrochanteric and diaphyseal femoral stress fractures associated with long-term alendronate or other bisphosphonate usage. Several patients completely fractured their femurs prior to referral. Most patients had consulted other physicians and were referred for presumed neoplasms. All patients had been diagnosed with osteoporosis and had been treated with bisphosphonates. Their plane radiographs revealed abnormalities that are pathognomonic of bisphosphonate-associated stress fractures. However, due to the subtle nature of these new unfamiliar abnormalities, most were unrecognized as such by clinicians (including experienced ISTA member hip surgeons) and radiologists. This series is presented to illustrate this pattern of impending fracture.

The authors have reviewed and will present a series (n=17) of femoral stress fractures in bisphosphonate-treated patients to illustrate the clinical and radiographic pattern of these stress fractures, and review their treatment.

The most common lesion is a subtrochanteric lateral cortical thickening that in actuality is a horizontal plane “dreaded black line” of a stress fracture with surrounding proximal and distal cortical thickening of the endosteal and periosteal bone. The stress fracture line is obscured unless a near-perfect radiographic projection is obtained. The lesion is best seen with CT scans. MRI scans reveal the stress fracture lines with surrounding edema (Fig 1), which may be misinterpreted as a tumor. Without treatment, a low-impact completed fracture will likely occur.

Many bisphosphonate-associated impending subtrochanteric femoral stress fractures are misdiagnosed as trochanteric bursitis, leading to subsequent displaced subtrochanteric fractures [Fig. 2 - Note subtle impending fracture lesion on right, completed fracture on left]. The clinical and subtle radiographic findings must be recognized by orthopaedic surgeons, particularly hip surgeons, to prevent these complete fractures. These fractures are preventable with internal fixation. Long-term administration of bisphosphonates can have adverse effects, and alternatives to long-term continuous dosing must be investigated to determine optimal administration regimens.

Perioperative infections can cause devastating results, especially in cases employing endoprostheses and/or allografts. To minimize bacterial contamination and thereby decrease infection rates, a series of experiments was performed to determine the role of several factors on intraoperative contamination.

In an initial pilot study, 102 surgical team members participating in clean orthopaedic cases were prospectively randomized to exchange or not exchange their outer pair of gloves one hour into the surgical procedures. Rodac plate cultures of the surgeon’s dominant gloved hand and of his or her gown sleeve were taken at baseline and again 15 minutes after potential glove exchange. The surgical gown type (reusable cloth versus disposable paper) utilized in each case was recorded. An unexpected overwhelming effect of gown type on bacterial contamination rates was detected, which overpowered any effect of glove exchange. The outer glove exchange experiment was then repeated with 251 prospectively randomized surgical team members, with all team members utilizing only disposable paper gowns. Otherwise the experimental protocol was the same. A final experiment was devised to test bacterial strike through of the two gown types. A standardized suspension (3 ml of coagulase negative staphylococcus containing 108 bacteria/ml) was applied to one side of the test materials and compressed with a 10 lb. weight. A rodac culture plate was applied to the opposite side of the material to determine bacterial strike through rates utilizing previously validated methodology.

The initial pilot experiment revealed a baseline sleeve culture positive rate of 41% with cloth gowns versus only 13% with disposable gowns (p=0.002, Students t-test). Cultures of the glove one hour and fifteen minutes into the operations revealed a 31% culture positive rate with reusable cloth gowns versus only 7% with disposable gowns (p=0.001), with a 4.38 x odds ratio. There was no statistically significant difference in the glove culture positive rate at one hour and fifteen minutes based on glove exchange (19% with glove retention vs. 10% following glove exchange p=0.19). There was no statistically significant difference in the culture positive rate between the two gown types when tested straight out of their sterile packaging (reusable gowns two positive cultures out of 50 cultures, disposable gowns zero positive cultures out of 50 cultures). On the second glove exchange experiment, surgeons exchanging gloves one hour into the case had a positive glove contamination rate of 13% compared to 23% in those retaining their original glove (p=0.04 Student’s t-test, odds ratio 0.51). The bacterial strike through study revealed that 22 of 25 cloth gowns allowed transmission of bacteria, whereas only 1 of 25 disposable paper gowns allowed transmission of bacteria (p=0.001, nonparametric sign rank test).

The choice of gown type had the greatest effect on the intraoperative culture positive rate of the surgeon’s dominant hand glove in our studies. Based on these results, at our institution, all orthopaedic surgeons now utilize only disposable paper gowns on all cases employing allograft or endoprosthesis implantation. We strongly recommend that only disposable paper gowns be utilized for any case with any orthopaedic implant materials and such gowns should be considered for all surgical cases. Exchange of the surgeon’s outer gloves prior to handling orthopaedic implant devices, especially if an hour of operating time has already elapsed, is also a recommended and prudent practice to diminish intraoperative contamination of the implant materials. The utilization of disposable drapes in addition to disposable gowns is also recommended due to the lower likelihood of bacterial strike through with currently available disposable synthetic materials. Following these recommended guidelines should help surgeons minimize the risk of intraoperative contamination and should thereby reduce the rate of infections.

Introduction: Pelvic and acetabular reconstruction following tumor resections are often difficult and fraught with complications. This is the first report of a reconstruction utilizing sacral implantation of an acetabular component, a relatively simple procedure.

Materials and Methods: A 74 year-old man developed recurrent low-grade chondrosarcoma in his ilium. Prior resections had included total hip reconstruction with massive cemented acetabular components. A combined Type I and II internal hemipelvectomy with endoprosthetic reconstruction were performed. Following resection, his sacrum and a small fragment of remaining ilium at the sacroiliac joint was reamed to accept a 48 mm porous coated acetabular component. It was press- fit into place and further secured with two central and three rim screws. A constrained cup liner was used. A proximal femoral endoprosthesis was constructed from a commercially available modular oncology system. Additional resection of the superior and inferior pubic ramie was required to minimize the likelihood of endoprosthetic impingement and leverage-induced dislocation. A soft tissue reconstruction of the abductors was accomplished.

Results: He remains free of recurrence 15 months post-operative. He ambulates full weight bearing with crutches. His leg is neurovascularly intact and he is pleased with his results. A videotape, demonstrating his gait, will be shown

Discussion: The author knows of one similar reconstruction that was performed at another center (unpublished data). That other patient suffered acetabular component dislodgement. The intraoperative leverage-induced dislocation of the hip was the important determination. Pubic rami resection may be required to prevent femoral impingement and instability. The use of multiple fixation screws also improved component fixation.

Conclusion: Placement of a well fixed, constrained, acetab-ular component into a retained sacrum at the level of the SI joint provides an alternative limb salvage technique.

Massive bone replacing endoprostheses have become a well-recognised option in reconstruction of massive bone defects following tumor resections of the humerus, femur and proximal tibia. While the design of such bone replacements is somewhat standardised, massive endo-prosthetic replacements of the proximal radius have not been described. Previous work with radial head replacements for arthritis and fracture indications has been performed, but a massive replacement of the proximal radius has not been reported. The design for such a prosthesis has not been described. Herein, we present our initial case with a massive custom proximal radius replacement, and the incorporated design features.

A 43 year old gentleman presented with progressive destruction of the proximal right radius from meta-static renal cell carcinoma despite radiation treatment. His systemic disease was under satisfactory control. He had undergone a nephrectomy (37 months previously), hip replacement for metastatic disease (28 months previously) and internal fixation of a humerus fracture (10 months previously). Prior treatment of his radius included cast immobilisation and radiation treatment of a pathologic fracture 13 months preoperatively. He refractured his partially healed pathologic fracture two weeks prior to presentation. Following staging with CT and MRI scan, a custom proximal radius endoprosthe-sis was designed that replaced 13 cm of the proximal radius. It was designed with 6 degrees of radial bow. The design specifics will be presented during the presentation. Surgical technique will be demonstrated. By one month postoperatively, his elbow range of motion was from 10 degrees to 140 degrees of flexion, with 90 degrees each of supination and pronation. He continued to have excellent use of his arm until he developed brain metastasis 10 months postoperatively.

Massive custom proximal radius endoprostheses of this design may be useful in the reconstruction of meta-static and primary tumors of the forearm. They are compatible with preservation of motion, and may provide additional stability to the elbow in patients whom soft tissue may be compromised due to tissue destruction or tissue loss secondary to neoplasia.