Keywords
Complication - foreign body - tibiofemoral joint - canine
Introduction
There are reports of joint foreign bodies caused by penetration of the skin or after
arthroscopy in both human or veterinary medicine.[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10] Stifle joints arthroscopic removal of bullets, metal fragments, needles, glass and
plastic objects have been reported.[3]
[5]
[10]
[11]
[12] When being lodged intra-articular, foreign bodies can cause lesions of the cartilage,
menisci or ligaments.[10]
[11]
[12]
[13]
[14]
We report an unusual case in which arthroscopy was used to remove a broken and previously
lost tip of a screwdriver from the medial aspect of the tibiofemoral joint of a small
dog. There seems no similar report in dogs of a metallic foreign body penetrating
and lodging within the joint without, evidently, causing any clinical signs for several
years.
Case Report
A 7-year-old male Jack Russell Terrier was presented for a non-weight-bearing right
hind-limb lameness of 1-week duration, right stifle pain and joint swelling. Sudden
onset of lameness occurred while the dog was walking on a leash without a history
of trauma or excessive exercise.
The dog's medical history included a right distal femoral Salter-Harris type I fracture,
which occurred when the dog was 9 months old ([Fig. 1A, B]). Fracture repair was performed using one locking plate and six screws (PAX 2.4mm
Polyaxial Locking Reconstruction Plate System, Securos Surgical, Massachusetts, United
States) ([Fig. 1C, D]). At 3 months, fracture healing was confirmed radiographically ([Fig. 2A, B]). At 7 months, a radiographic examination showed some reabsorption of bone, secondary
to alleged stress shielding ([Fig. 2C, D]). A radio-dense fragment of ∼2.5 × 2 mm dimension was noticed at the level of the
distal pole of the patella in the mediolateral view and at the level of the lateral
femoral condyle on the craniocaudal view ([Fig. 2C], [D], arrows). Plate and screws were removed. Postoperative radiographs showing implant
removal were missing.
Fig. 1 Jack Russell Terrier, male, 9 months old. Mediolateral view and craniocaudal view
of the right femur (A, B). Salter-Harris type I fracture was diagnosed. Fracture repair was performed using
a 6-hole locking plate (C, D).
Fig. 2 Jack Russell Terrier, male, 1 year old. Three-month radiographic examination. Mediolateral
(A) and craniocaudal (B) radiographs of the right femur showing bone healing. Jack Russell Terrier, male,
16 months old. Seven-month radiographic examination mediolateral (C) and craniocaudal (D) radiographs of the right femur showing the foreign body (arrows).
There was no apparent skin wound or redness over the stifle joint, and no trauma was
reported by the owners. Orthopaedic examination revealed pain upon stifle palpation
or joint motion and mild swelling of the stifle. The drawer test and the tibial compression
test were negative. A provisional diagnosis of nonspecific synovitis was established.
General haematological and biochemical tests showed no abnormalities. Plain stifle
radiographs were obtained under general anaesthesia. Mediolateral or caudocranial
orthogonal radiographs showed a distinct small metal-dense foreign body in the region
of the medial tibiofemoral joint ([Fig. 3A, B]). The radiographs revealed that the two most proximal screws were left in situ after
implant removal which occurred 5 years earlier. The patient was prepared for arthroscopic
foreign body removal. Radiographs just before arthroscopy confirmed that the foreign
body had not changed position. The stifle joint was inspected through a lateral parapatellar
arthroscopic portal, just lateral to the patellar tendon and distal to the distal
pole of the patella utilizing a 2.3 mm 30-degree fore-oblique arthroscope. Synovitis
was present. Trochlear groove and patella seemed normal. Lateral femoral and tibial
condyles, as well as the cruciate ligaments and the menisci, seemed uninjured. The
cranial and caudal cruciate ligaments were probed and assessed for stability. The
small foreign body was identified at the medial tibiofemoral joint partially sunk
into the tibial cartilage. ([Fig. 4A, C]). Chondral lesions were identified at both tibial and femoral medial condyles ([Fig. 4B, D]). The foreign body was identified as being a broken Torx-type screwdriver tip. During
arthroscopic surgery, the foreign body was changing position and was dislodged because
of the flushing liquid's turbulence. The foreign body was extracted using an alligator
grasper ([Fig. 4E, F]). The complete removal of the fragment was confirmed radiographically ([Fig. 3C]) The dog was discharged from the hospital the same day and was weight-bearing. The
patient's postoperative course was unremarkable and recovery to full weight-bearing
and pain-free full range of motion occurred within 3 days.[15] At 2, 4 and 8 weeks postoperative follow-ups, the dog showed no further signs.
Fig. 3 Jack Russell Terrier, male, 7 years old. Preoperative foreign body arthroscopic removal
mediolateral (A) and craniocaudal (B) views of the right femur showing the tibiofemoral joint space location (arrows).
Mediolateral view of the right stifle after fragment removal (C).
Fig. 4 Arthroscopic images of the foreign body (A, C) and femoral and tibial chondral lesions, respectively (B, D). Images of the screwdriver fragment measurement (E, F).
Discussion
Given a clear indication for surgical foreign body removal, this could have performed
either arthroscopically or through open arthrotomy. Arthroscopy was preferred. Advantages
of arthroscopy included decreased morbidity through mini-invasiveness, rapid recovery,
decreased complication rates, improved functional outcomes, shorter anaesthesia and
surgery times, possibility for day-hospital care and enhanced client satisfaction.[16]
[17]
[18]
[19]
[20]
[21]
[22] Disadvantages include the relatively high level of skill required, the high cost
of the equipment and relatively high costs to the client.
Arthroscopy has been recognized as an efficient means for foreign bodies removal from
the stifle joint in human surgery.[5]
[8]
[9]
[10]
[11]
[12]
[14]
[23] Multiple attempts to arthroscopically remove a broken tip of a curette from an elbow
joint failed in a dog.[7] The fragment then migrated into the radial fossa of the humeral condyle and was
left in situ. The dog made an uneventful recovery and, 6 months after surgery showed
no lameness except after rest, and there was no evidence of later migration of the
metallic fragment.[7] In our case, the foreign body remained clinically silent for more than 6 years before
producing clinical signs. In case of a foreign body left in situ, clinical examination
and radiographic inspection should be performed routinely for early detection of potential
damages. Foreign bodies can change position over time and sometimes cause delayed
complications, as in our case.[3]
[10]
Plain radiographs were able to detect the foreign body 7 months after surgery. The
patient in this case had remained with no evident signs for about 6 years.
Grasping the fragment was technically difficult. The foreign body was continuously
changing position because of the ingress-fluid turbulence within the relatively large
joint space and because of the force of gravity on the small metallic object. The
dislodged piece may migrate to the caudal joint compartment facilitated by the supine
position of the dog for arthroscopy (dorsal recumbency). Controlling or closing fluid
flow can help during searching for and grasping the foreign body.
In the knee of a human patient, a magnet was used to catch the fragment of a broken
sewing needle and to deliver it into the anterior compartment during the removal attempt.[10] However, we failed to know whether the metal of the screwdriver piece would have
acted like a ferromagnetic material.
To ensure that the position of the metal fragment had not changed, radiographs were
repeated. Intraoperative X-ray or fluoroscopic examination could be of help in case
of migrating foreign bodies.[1]
[3]
[24]
The fragment location did not look questionable on our radiographs. In case of doubt,
a computed tomography should be performed to detect the exact location just before
surgery.
The screwdriver fragment was neither visible on the postoperative radiographs nor
at the 3-month radiographic examination ([Fig. 2A, B]). The fragment was first detected at the 7-month radiographic examination when implant
removal was performed ([Fig. 2C, D]). We presume that the screwdriver tip broke during fracture plating and remained
stuck within the screw-head recess until later migration through which the fragment
became evident at the 7-month postoperative radiographs ([Fig. 2C, D]).
The synovitis was probably secondary to cartilage wear at the tibial and femoral medial
condyles, or it was secondary to the mechanic irritation from the metallic foreign
body.
Intra-articular foreign bodies usually provoke remarkable inflammation. Often neutrophils
are the first subpopulation of leukocytes that appear at the injury site, and neutrophil
invasion is followed by a sequential increase in the concentrations of macrophage
subpopulations.[25]
[26] Polymorphonuclear neutrophils are the first cells to take part in the local reactions
to the foreign body at the aseptic knee. The local reactions caused by foreign bodies
vary widely.[10]
[26] In the case of intra-articular sterile foreign bodies, as in our case report, laboratory
tests might be unhelpful. On admission, general haematological and biochemical tests
showed no abnormalities. Maybe because there was no infection, and the acute phase
of the inflammation was short and limited to the joint compartment, laboratory tests
remained in the normal range.
Why and how the screwdriver tip broke, why the two most proximal screws were left
in situ after implant removal and why the metal fragment was not removed during the
procedure for implant removal is not known. The operative report was missing.
A high index of suspicion for such iatrogenic complications should be maintained even
a long time after surgery.
