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Patient 1
DR. (B)(6) WAS CALLED ON OCTOBER 11TH BY ZKC ENGINEERING TO FOLLOW UP ON THE EVENTS THAT LED TO THIS COMPLAINT. HE SAID THAT HE DRILLED INTO THE PATIENT'S MEDIAL FEMORAL CONDYLE WITHOUT DIFFICULTY. HE COMMENTED THAT IT WAS NOT PARTICULARLY HARD BONE IN THIS LOCATION AND HE DID NOT NEED TO REDIRECT THE CANNULA. HE THEN PROCEEDED TO INJECT THE BSM WITHOUT DIFFICULTY. WHEN HE WENT TO PLUNGE THE BSM, DR. (B)(6) WAS UNABLE TO FULLY PLUNGE THE STYLUS IN; THE TIP OF THE STYLUS RESTED BETWEEN THE 2ND AND 3RD FENESTRATION (AS NOTED BY RETURNED INSTRUMENT). HE THEN WENT ON TO PERFORM A NORMAL KNEE ARTHROSCOPY. IN THE PROCESS OF FLEXING AND EXTENDING THE KNEE, HE HEARD A POPPING SOUND; THE SURGEON DOES NOT BELIEVED THAT THE CANNULA WAS BUMPED IN ANY WAY. THE KNEE WAS RETURNED TO A STRAIGHT POSITION AND A C-ARM IMAGE WAS TAKEN. THE ACCUPORT TIP SEEMED BENT, SO DR. (B)(6) CHOSE TO LEAVE THE CANNULA AND KNEE ALONE, WAIT FOR THE BSM TO HARDEN (~8MIN), AND THEN REMOVE THE CANNULA BEFORE HE RETURNED TO THE ARTHROSCOPY. AS THE CANNULA WAS REMOVED, IT BECAME EVIDENT THAT THE TIP HAD BROKEN OFF AT THE 3RD FENESTRATION. THE INSTRUMENT WAS STERILIZED AND RETURNED TO ZKC'S 805 FACILITY. THE SURGEON DECIDED TO LEAVE THE PIECE IN THE BONE AND PROCEEDED WITH THE SURGERY. HE COMMENTED THAT THE DELAY IN SURGERY WAS LESS THAN 15 MINUTES, AND THAT TIME WAS SPENT ASSESSING THE SITUATION. DR. (B)(6) ALSO COMMENTED THAT THERE WAS SOME EXTRAVASATION OUT OF THE ARTICULAR SURFACE AROUND THE LESION LOCATION, BUT THAT IT WAS VERY EASY TO CLEAN UP. HE ALSO NOTED THAT THIS PATIENT HAD GOOD LEG MUSCLE FOR HIS AGE AND THAT COULD HAVE CONTRIBUTED TO THE BREAKAGE DURING FLEXION/EXTENSION. THE BROKEN PART WAS REVIEWED BY THE ZKC ENGINEERS AND FOUND TO EXHIBIT SIGN OF BENDING FAILURE. THE FENESTRATION SIDE SEEMED TO BE NECKING AND THE OPPOSITE SIDE SHOWED A JAGGED BREAK. WHEN VIEWED PERPENDICULAR, SO THAT THE NECKING IS ON THE RIGHT AND THE JAGGED EDGE IS ON THE LEFT, THE CANNULA BENDS AWAY FROM THE FENESTRATION SIDE (LEFT). THE FRACTURE FOLLOWED THE THREADING, EXCEPT FOR 1 POINT WHEN IT JUMPED UP TO THE NEXT THREAD; BOTH ENDS CROSSED THE 3RD FENESTRATION. AN ATTEMPT TO REPLICATE THIS TYPE OF FAILURE HAS BEEN MADE ON CADAVERS IN THE PAST, BUT MUSCLE STRENGTH AND BONE DENSITY WERE NOT SUITABLE REPLICAS AND WE COULD NOT RECREATE THE EVENT. THIS INVESTIGATION CONCLUDES THAT THE BREAKAGE OF THE ACCUPORT CANNULA COMES FROM THE UNSUPPORTED BENDING OF THE SIDE-DELIVERY CANNULA. WHILE OTHER UNKNOWN ACTIONS MAY HAVE WEAKENED THE CANNULA, THE MUSCULAR FORCES INDUCED DURING THE FLEXION AND EXTENSION OF THE LEG WERE MOST LIKELY THE CAUSE OF THIS BENDING FORCE; THIS IS BELIEVED TO BE THE ONLY FORCE ACTING ON THE CANNULA DURING THE TIME THAT THE "POPPING" SOUND WAS HEARD. BUT, AS THIS COULD NOT BE REPLICATED, WE CANNOT BE SURE. THIS INVESTIGATION CONCLUDES THAT THIS BREAKAGE COMES FROM THE UNSUPPORTED BENDING OF THE SIDE-DELIVERY CANNULA.