Endoscopy for cement removal in revision arthroplasty of the hip

Impact of stem profile on the revisability and the need for osteotomy in well-fixed cemented revision total knee arthroplasty implants

INTRODUCTION

While re-revision total knee arthroplasty (ReRTKA) steadily increases, the ease and bone-sparing removal of RTKA implants is gaining more and more in importance. Biomechanical data suggest that cemented conical stems can be removed significantly easier than cylindrical stems. However, no clinical evidence exists supporting this observation. Aim of this study was to compare the revisability and need for osteotomy (OT) between removals of well-fixed cemented conical vs. cylindrical RTKA stems.

MATERIALS AND METHODS

55 removals of well-fixed full-cemented RTKA stems (29 knees) performed between 2016 and 2018 were retrospectively analyzed. Main outcome variables were: bone loss, fractures, osteotomy incidence, surgery duration, early postoperative complications (EPC), hemoglobin drop and blood transfusion. SPSS was used for the statistical analysis.

RESULTS

44.8% were conical, 48.3% cylindrical, and 6.9% combined stem designs. Causes for re-revision were PJI (75.9%), malposition (17.2%) and persistent pain (6.9%). 10 stem removals (18.2%) required an OT (four femoral, six tibial): eight stems (14.5%) had cylindrical and two (3.6%) conical designs (P = 0.041). Fractures were noted solely in removals without OT (11.1% vs. 0%,). There was a tendency to more bone loss in cylindrical stem revisions (53.8% vs. 32%, P = 0.24). A longer overall surgery time was observed in revisions of cylindrical stems (+ 37 min, P = 0.05). There was higher hemoglobin drop and need for blood transfusion in revisions of cylindrical stems or after OT but without reaching statistical significance. The EPC rates were slightly higher in ReRTKA on cylindrical stems (P = 0.28).

CONCLUSION

Well-fixed cemented conical stems may be revision friendlier with less demands on OT and shorter overall surgery time than cemented cylindrical stems.

Osteomyelitis of the femur effectively treated with medulloscopy debridement: a case report

BACKGROUND

Medulloscopy refers to the visualization of the intramedullary canal with an arthroscope, providing access to the infection site without the need for an extensive approach therefore not compromising the surrounding soft tissue. It provides information regarding the extent of the infected endosteal surface of bone, and it allows a thorough debridement of the intramedullary canal in a controlled manner. Therefore, it can be used as an adjunct to traditional open surgical techniques, to perhaps help to visualize hard to see intramedullary areas.

MATERIALS AND METHODS

This article reports a patient with chronic osteomyelitis of the distal metaphysis of the femur that was treated successfully with intramedullary debridement through medulloscopy. The sinus tract reaching down to the femoral bone and communicating with the intramedullary canal was excised, and a cortical window was formed through which the arthroscope was inserted and thorough irrigation of the intramedullary canal and excision of necrotic and infected bone was done. A second medulloscopy through the same approach was necessary 3 months later because of persistent infection. RE: SULTS: At 3-year follow-up, the patient was well without any clinical or radiographic evidence of recurrent infection.

CONCLUSION

Medulloscopy can be very useful in localized osteomyelitis as an adjunct to traditional surgical techniques; it helps to visualize hard to see intramedullary areas and adequately addresses the infection, while the damage to surrounding soft-tissue is limited.

Broken guidewire protruding into the hip joint: A bone endoscopic-assisted retrieval method

Broken implants, especially broken wires at difficult sites, may pose a challenge for the treating orthopedic surgeon. We describe a method for extraction of a broken guidewire that was, protruding into the hip joint following the insertion of a proximal femoral nail. A 35-year-old man with displaced femoral neck fracture with ipsilateral fracture shaft of femur was operated and fixed with long proximal femoral nail. The guidewire of proximal screw broke during the process of drilling. The tip of the 2-cm-long broken guidewire was touching the articular surface. The guidewire was misdirected posteroinferiorly from its path for the insertion of the proximal screw (6.8 mm), this screw was removed and bone endoscopy was performed with a 30° arthroscope. The broken end of the guidewire was located under direct vision. The grasper was introduced with its jaws at the 8 O'clock position and its position was confirmed under a C-arm image intensifier in both anteroposterior and lateral views. The broken end of the guidewire was grasped and it was retrieved. The screw was replaced in its original track to complete the procedure. The fractures united and patient was asymptomatic when last followed-up at 12 months.

The use of medulloscopy for localized intramedullary lesions: review of 5 cases

We report 5 cases of a localized lesion (4 with osteomyelitis and 1 with an intraosseous ganglion cyst) that were treated successfully by medulloscopy. Medulloscopy is a standard arthroscopic technique for visualizing the intramedullary canal of the tibia. Two portals were created to allow easy access and triangulation to the lesion, one for the 5-mm arthroscope and the other for the instrument. Debridement, irrigation, and resection of the sequestrum were performed for the cases with osteomyelitis, and the intraosseous ganglion cyst was treated with biopsy, debridement, and autogenous bone grafting. All cases were treated successfully with medulloscopy and did not show recurrence at the last follow-up. In addition, there were no complications related to the procedure.

Cement removal and bone bed preparation of the femoral medullary canal assisted by flexible endoscope in total hip revision arthroplasty

PURPOSE

The flexible endoscope was applied to cemented femoral medullary canal to obtain better visual field and assist surgical procedures in total hip revision arthroplasty.

METHODS

Fifteen cases of failed cemented total hip joints were analyzed. Efficacy of cement removal was assessed, combined with degree of implant loosening and bone defect, postoperative radiographic findings, and perioperative status of the patients and complications. Status of the bone bed between bone and cement and that of bone grafting were also evaluated.

RESULTS

The cement mantle was efficiently extractable in all cases under good exposure and with maintenance of efficient working space. Endoscopic time for cement removal was dependent on the status of the cement-bone interface and bone defect. Rigid and less loosened interfaces, as well as cases of minimal bone defect, required a longer time. However, it was effective to confirm the status of the bone bed during the procedure. Occult foreign-body reaction was detectable in three cases of unloosened interface under endoscopic inspection. Impaction bone grafting was performed in eight cases. The scope was also helpful to confirm the status of a grafted bone bed. Three fractures occurred, of which two cases revealed minor cement leakage and one required additional osteosynthesis with extensive approach. JOA Hip Score was improved, and the implants were stable at latest follow-up. Dislocation was found in two cases. Neither thromboembolic events nor infection was found.

CONCLUSIONS

Cement removal in the femoral medullar canal was effectively performed not only in the cases of loose interface but also those of rigid and less-loosened interface under flexible endoscopic inspection. The scope could support cement removal in femoral revisions under good exposure and maintenance of working space, as well as confirmation of bone bed state. Although one case required an additional approach, application of the flexible endoscope has potential merit to contribute to less invasive total hip revision arthroplasty, possibly combined with other refined devices of cement extraction.

Fat marrow embolism during intramedullary bone endoscopy: an experimental study in sheep

We present a study designed to investigate whether the intramedullary bone endoscopy (IBE) procedure within the cavity of an intact long bone will create embolic loads on the lungs similar to that of other orthopedic procedures (e.g., stem implantation in total hip arthroplasty [THA]). In a sheep model, 10 animals underwent the IBE procedure with complete perioperative anesthesiology monitoring. The lungs were harvested postoperatively and examined for fat embolisms. One animal showed evidence of intraoperative fat embolism with temporary increases in mean pulmonary arterial pressure (MPAD) and the mean CO(2)-gradient. The histological examination in this animal revealed fat embolism with a 2% surface area of the investigated fields covered with fat vacuoles. All peri- and postoperative data on the other nine animals were normal. Our findings indicate that, as with other intramedullary manipulation in intact long bones, there is a potential risk for systemic fat excavation during IBE. However, the embolic load is much lower than the rates reported for other orthopedic interventions.