POSTER ABSTRACTS - ISAKOS

Introduction: Among several methods for fixation
of osteochondral lesion, fixation with
biodegradable pins has the advantage of easy
handling and no need for hardware removal. In
this study, we reported our experience of internal
fixation of unstable osteochondral lesion of the
knee with poly-L-lactic acid (PLLA) pins.
Materials and Methods: Thirty patients with
symptomatic osteochondral lesions (14
osteochondritis dissecans [OCD] and 16
osteochondral fractures) were treated with PLLA
pins. There were 22 males and 8 females with a
mean age of 20 years, ranging from11 to 36 years.
All lesions were unstable and the average size was
4.5 (2.1~8.8) centimeter square. The medial
femoral condyle was affected in 11 patients, and
the patellofemoral joint was affected in 19
patients. These lesions were fixed by multiple
PLLA pins (1.5 - 3mm diameter) after curettage of
the bone bed, followed by autogeneous iliac bone
grafting when necessary. Their clinical symptoms
and healing scores were evaluated by X-ray, MRI
and reconstructed CT. Second-look arthroscopy
was performed in 13 OCD and 8 fracture patients.
Results: Mean follow-up was 14 months. All
patients but one had no or decreased knee pain.
Only one patient experienced joint effusion.
Healing scores improved in all the patients. At
second-look arthroscopy, union of the fragment
was confirmed in all the fracture patients. In one
of the OCD patients, detachment of the lesion was
found. Pin protrusion from the articular surface
and cartilage damage at the opposite surface was
observed in two cases.
Conclusion: Internal fixation with PLLA pins is
effective method for the treatment of
osteochondral lesion of the knee. However,
considerable caution should be directed to the
possibility of pin protrusion and subsequent risk
of erosion of the opposite cartilage and tissue
reaction.
E-poster w/ Standard #822
Postoperative Range of Motion for Cruciate-
Retaining Total Knee Arthroplasty -
Relationships with posterior condylar offset
and evaluation of rollback-
Jun Nishiike, kushiro, JAPAN, Presenter
Humihiro Oha, Hakodate, Hokkaido, JAPAN
Takashi Ishida, Hakodate, Hokkaido, JAPAN
Shigeru Yamane, Hakodate, Hokkaido, JAPAN
Yasumitsu Ohkoshi, Hakodate, Hokkaido, JAPAN
Kazuki Yamamoto, Hakodate, Hokkaido, JAPAN
Shinya Nagasaki, Hakodate, Hokkaido, JAPAN
Wataru Ebata, Hakodate, Hokkaido, JAPAN
Tomoyuki Hashimoto, Hakodate, Hokkaido,
JAPAN
Hiroshi Tada, Hakodat, Hokkaido, JAPAN
Keiichi Shigenobu,Hakodate, Hokkaido ,JAPAN
Masahiro Kanayama, Hakodate, Hokkaid, JAPAN
Hakodate Central General Hospital, Hakodate,
Hokkaido, JAPAN
(Objective)Many factors influence the flexion
angle after total knee arthroplasty (TKA). In this
study, the relationships of the postoperative range
of motion with the posterior condylar offset (PCO)
and femoral rollback were investigated.
(Materials and Methods)From January 1996 to
June 1999, 45 patients (52 joints) underwent
cruciate-retaining TKA (NexGen, Zimmer, Inc.) in
our department. Thirty- one patients (38 knees)
were directly examined (the CR group). The mean
follow-up period was 6.2 mos (4.7 - 8.5 mos). A
postoperative lateral roentogenogram of the knee
joint at maximum flexion was taken under image
TV. The PCO and the contact point (CP) of the
tibio-femoral joint were measured from each film.
As a control group, lateral roentogenograms were
taken at every 10 for 30 normal knees (mean age:
27.1 yrs). CP values within 1 SD of the control
group were defined as normal. Values above the
normal range were evaluated as excessive rollback
(ER), while lower values were evaluated as
insufficient rollback (IR).
(Results) In the CR group, the mean postoperative
maximum flexion angle was 119.5 ± 16.5 . There
was no relationship between the range of motion
and the PCO (pre - post op. difference; R2 =
0.004). The CP value was 0.62 ± 0.02 in the control
group and 0.65 ± 0.09 in the CR group. In the CR
group, the CP value showed considerable variance
and had no relationship with the postoperative
flexion angle. The percentage of the cases
assessed as normal CP was 36.8%, while ER and IR
were 52.7% and 10.5%, respectively.
(Conclusion) In this study, no relationship was
found between the PCO and the postoperative
range of motion. Analysis of the CP showed that
only 36.8% of the CR group evaluated as normal
the postoperative rollback. It was concluded that
the mechanical environment for the posterior
cruciate ligament was not physiologically
reconstructed in more than 60% of the cruciateretaining
TKA.