Successful outcome with minimally invasive plate osteosynthesis for periprosthetic tibial fracture after total knee arthroplasty.

INTRODUCTION: The incidence of periprosthetic fractures after total knee arthroplasty (TKA) is increasing, and treatment is becoming more necessary. In periprosthetic tibial fractures, the stem of the tibial component largely occupies the medullary canal of the proximal tibia, which limits the selection of implants. The purpose of this study was to evaluate the effectiveness of the minimally invasive plate osteosynthesis (MIPO) technique with locking plates for periprosthetic tibial fractures after TKA. MATERIALS AND METHODS: Sixteen patients with periprosthetic tibial fracture after TKA were included. There were 6 type II and 10 type III fractures according to the Felix classification. Ten patients had fractures in the proximal metaphysis, and 6 in the diaphysis. MIPO using locking plates was performed on the medial side in 4 cases, the lateral side in 2 cases, and both in 10 cases. Radiographic results included time to union, alignment, and malunion. Clinical results included range of motion (ROM), functional activity data, Knee Society scores, and complications. RESULTS: Fourteen of 16 fractures achieved union at 17.1 weeks (range, 14-24) postoperatively. There were 2 failures that required a secondary procedure. Except one for 1 case with varus malunion, all had acceptable alignment. Mean ROM at the final follow-up was 108.8° (range, 15-135°), and 15 patients recovered pre-injury knee joint activity. Mean knee and function scores were 88.9 (range, 77-100) and 83.3 (range, 60-100), respectively. Knees with fewer than 8 cortices giving purchase to screws in the proximal segment showed higher failure rates (P=0.025). DISCUSSION: MIPO with locking plates can achieve satisfactory results for periprosthetic tibial fractures after TKA. Rigid fixation of the proximal segment may be necessary for successful outcome. LEVEL OF EVIDENCE: IV.

Osteophyte excision without cyst excision for a mucous cyst of the finger.

Osteophyte excision is a mainstay of treatment for mucous cyst combined with Heberden's node in a distal interphalangeal joint or in an interphalangeal joint of the thumb. The aim of this study was to evaluate the results of osteophyte excision without cyst excision for the treatment of a mucous cyst combined with Heberden's node. The medical records of 37 patients (42 cases) with a mucous cyst with Heberden's node were retrospectively reviewed. Thirty-eight of 40 cases with available pre-operative simple radiographs showed evidence of joint arthrosis. A T-shaped skin incision of the joint capsule between the extensor tendon and lateral collateral ligament was used. Osteophyte excision without cyst excision was performed. All cysts, except one, regressed without recurrence or a skin complication after osteophyte excision, but eight cases showed post-operative pain and loss of range of motion. Osteophyte excision without cyst excision may be a good treatment choice for mucous cyst of the finger.

Bone transport with an external fixator and a locking plate for segmental tibial defects.

Although gradual bone transport may permit the restoration of large-diameter bones, complications are common owing to the long duration of external fixation. In order to reduce such complications, a new technique of bone transport involving the use of an external fixator and a locking plate was devised for segmental tibial bone defects. A total of ten patients (nine men, one woman) with a mean age at operation of 40.4 years (16 to 64) underwent distraction osteogenesis with a locking plate to treat previously infected post-traumatic segmental tibial defects. The locking plate was fixed percutaneously to bridge proximal and distal segments, and was followed by external fixation. After docking, percutaneous screws were fixed at the transported segment through plate holes. At the same time, bone grafting was performed at the docking site with the external fixator removed. The mean defect size was 5.9 cm (3.8 to 9.3) and mean external fixation index was 13.4 days/cm (11.8 to 19.5). In all cases, primary union of the docking site and distraction callus was achieved, with an excellent bony result. There was no recurrence of deep infection or osteomyelitis, and with the exception of one patient with a pre-existing peroneal nerve injury, all achieved an excellent or good functional result. With short external fixation times and low complication rates, bone transport with a locking plate could be recommended for patients with segmental tibial defects.

Biomechanical properties after pre-twist of canine patellar tendon.

We studied what effect a rotational pre-twist of the patellar tendon had on its mechanical properties. We used the central strip of canine patellar tendons. The length, width and thickness of each specimen were measured and the specimens were mounted in custom-made aluminum pots. Five groups of 10 specimens each were measured with neutral rotation, 90 degrees external rotation, 180 degrees external rotation, 270 degrees external rotation and 360 degrees external rotation. The ultimate stress, ultimate strain, average elastic modulus, and strain energy density were measured. There were no statistically significant differences among the five groups. Twisting the graft up to 360 degrees did not decrease the biomechanical properties of the graft.

Fracture separation of the distal humeral epiphysis in children younger than three years old.

This study evaluated the change of carrying angle and the causes of cubitus varus after the fracture separation of the distal humeral epiphysis in young children. Twelve cases of fracture separation of distal humeral epiphysis were treated from January 1995 to July 1997. The age of all patients was younger than 3 years old. A metaphyseal fragment was seen in all cases (Salter-Harris type II), but the size of the metaphyseal fragment was either a very small flake or a large Thurston-Holland fragment. Posteromedial displacement was seen in all cases. There were three treatment groups: closed reduction with percutaneous pinning, closed reduction with cast, and cast without reduction. Follow-up period averaged 23.5 months (range, 12-40). Cubitus varus deformity was seen in seven cases, and six of them had a partial defect of the medial condyle that was avascular necrosis. The methods of treatment, age of injury, and the type of epiphyseal injury had no influence on the development of cubitus varus, but avascular necrosis of the medial condyle was related to the cubitus varus deformity (p<0.05). The results of this study suggest that fracture separation of distal humeral epiphysis in young children is likely to produce cubitus varus deformity with the development of avascular necrosis of the medial humeral condyle.