Knee osteoarthritis (KOA) is the most common knee joint disease. Although KOA belongs to a disease of degeneration of knee joint cartilage, its pathology involves cartilage, subchondral bone, meniscus, synovial membrane, articular capsule and other joint tissue. The infrapatellar fat pad (IPFP), an intracapsular but extrasynovial structure, has some special characteristics of endocrine metabolism, then it has double roles in the development of KOA, but its protective effect is much more than harmful effect. Considering protective roles of IPFP in KOA and some serious complications after IPFP resection, the surgeon shall protect IPFP as far as possible if total knee arthroplasty surgical field is good. If it is necessary to improve the surgical field, its fibrotic tissue even all part can be removed.
Adipose Tissue ; physiology ; Arthroplasty, Replacement, Knee ; Humans ; Knee Joint ; physiopathology ; surgery ; Osteoarthritis, Knee ; surgery

The capacity to perform certain activities is frequently compromised after total knee arthroplasty (TKA) due to a functional decline resulting from decreased range of motion and a diminished ability to kneel. In this manuscript, the current biomechanical understanding of hyperflexion and kneeling before and after TKA will be discussed. Patellofemoral and tibiofemoral joint contact area, contact pressure, and kinematics were evaluated in cadaveric studies using a Tekscan pressure measuring system and Microscribe. Testing was performed on intact knees and following cruciate retaining and posterior stabilized TKA at knee flexion angles of 90degrees, 105degrees, 120degrees, and 135degrees. Three loading conditions were used to simulate squatting, double stance kneeling, and single stance kneeling. Following TKA with double stance kneeling, patellofemoral contact areas did not increase significantly at high knee flexion angle (135degrees). Kneeling resulted in tibial posterior translation and external rotation at all flexion angles. Moving from double to single stance kneeling tended to increase pressures in the cruciate retaining group, but decreased pressures in the posterior stabilized group. The cruciate retaining group had significantly larger contact areas than the posterior stabilized group, although no significant differences in pressures were observed comparing the two TKA designs (p < 0.05). If greater than 120degrees of postoperative knee range of motion can be achieved following TKA, then kneeling may be performed with less risk in the patellofemoral joint than was previously believed to be the case. However, kneeling may increase the likelihood of damage to cartilage and menisci in intact knees and after TKA increases in tibiofemoral contact area and pressures may lead to polyethyelene wear if performed on a chronic, repetitive basis.
*Arthroplasty, Replacement, Knee ; Biomechanical Phenomena ; Cadaver ; Humans ; Knee Joint/*physiopathology/surgery ; Osteoarthritis, Knee/*physiopathology/surgery ; Patellofemoral Joint/physiopathology/surgery ; Posture/physiology ; Range of Motion, Articular

OBJECTIVETo investigate results of total knee arthroplasty using the long-stem tibial component combined with metallic wedge of knee prosthesis for the treatment of proximal defects.

METHODSFrom January 2011 to May 2013, 10 patients (11 knees) were treated with total knee arthroplasties using the long-stem tibial component with metallic tibial wedge of knee prosthesis. All the patients were female and the average age was 67 years old (ranged, 60 to 77 years old). All the patients were osteoarthritis. All the patients were classified as T2A style. The patients were evaluated according to knee score system (KSS).

RESULTSAll the patients were followed up for 12 months on average (ranged 3 to 29 months). The clinical outcome was assessed using KSS score, including knee pain score, knee stability score, knee range of motion score and knee walking score, knee stairs score. There were significantly differences at 6 weeks, 3 months, 6 months and 12 months between pre-and postoperative KSS score.

CONCLUSIONThe mechanical stability of tibial fixation in primary TKA is significantly increased by using the long-stem tibial component with metallic wedge of knee prosthesis, even in the presence of poor proximal bone.

Aged ; Arthroplasty, Replacement, Knee ; Female ; Humans ; Knee Joint ; physiopathology ; surgery ; Knee Prosthesis ; Male ; Osteoarthritis, Knee ; physiopathology ; surgery ; Range of Motion, Articular ; Tibia ; abnormalities ; physiopathology ; surgery

OBJECTIVETo observe the change of clearance and range of joint improved situation during total knee arthroplasty (TKA) by operating extended release manipulation of the posterior knee clearance.

METHODSA total of 120 patients with knee osteoarthritis undergoing unilateral TKA from March 2010 to March 2012 were equally randomized prospectively assigned to the experimental group and control group, each 60 cases. There were 46 male and 74 female patients, the mean age was 63.6 years (range from 49 to 75 years). After the osteotomy of the tibia and the femoral condyle and before the release of soft tissue intraoperation, patients in experimental group were taken the extended release manipulation of the posterior knee clearence while the control group were cleaned the osteophyte of the posterior condyle only, 2-sided paired t test was used to compare the clearence intraoperation and the time to flexion angle of 90° and 120° and the maximum angle after 3 months' follow-up.

RESULTSThere was no significant difference of the index between the experimental group and control group (P > 0.05). Between experimental group and control group, the difference was significant in extention clearance ((18.9 ± 1.5) mm vs. (17.9 ± 1.6) mm, t = 3.53, P < 0.01) intraoperation, and no significant difference in flexion clearance ((20.7 ± 1.8) mm vs. (20.2 ± 1.9) mm, t = 1.48, P > 0.05). It took longer time for the knee flexion range of motion to 90°(t = 10.2399, P < 0.01) or 120°(t = 11.142, P < 0.01) of the control group than that of the experimental group, and the difference of the maximum range of motion between experimental group and control group was significant statistically at the 3-months follow-up (t = 4.4255, P < 0.01). All the patients were followed up for 3 - 24 months, average of 14.6 months, no femoral component loosening happened.

CONCLUSIONSExtended release of the posterior knee clearance benefits the knee extension clearence intraoperation and functional exercise of range of motion postoperation, while it is no meaning to the flexion clearence.

Aged ; Arthroplasty, Replacement, Knee ; Female ; Humans ; Joint Capsule Release ; methods ; Knee Joint ; physiopathology ; surgery ; Male ; Middle Aged ; Osteoarthritis, Knee ; physiopathology ; surgery ; Osteotomy ; Range of Motion, Articular ; Treatment Outcome

OBJECTIVETo evaluate the clinical results of the medial patellofemoral ligament (MPFL) reconstruction combined with the lateral retinacular release for the treatment of recurrent patellar dislocation.

METHODSFrom March 2011 to June 2013, 15 patients with recurrent patellar dislocation underwent arthroscopic MPFL reconstruction combined with the lateral retinacular release. The graft was autogenous semitendinosus and semimembranosus tendon. There were 5 males and 10 females with an average age of 19.4 years old (ranged,14 to 32 years old). The patients suffered recurrent patellar dislocation at least twice preoperatively. Preoperative conventional X-ray, CT, and MR examination were used to analyze the causes of the patellofemoral joint and MPFL injury. Preoperative Lysholm score was 69.85 ± 11.52. During operation, the arthroscopic examination was performed to evaluate the patellofemoral alignment and patellar tracking.

RESULTSAll the patients were followed up for an average of 27.6 months (ranged,12 to 36 months) with no recurrent dislocation and sub-dislocation. All the patients showed negative apprehension test at straight and 30 ° flexions of knee. The range of motion of knee returned to normal level at 12 months after operation. There were no patients with subjective discomfort of knee. Postoperative Lysholm score was improved to 92.60 ± 5.75.

CONCLUSIONThe technique of arthroscopic MPFL reconstruction combined with the lateral retinacular release is an effective surgical procedure for the treatment of recurrent patellar dislocation, which can relieve the symptom of knee and improve the patella stability and knee function.

Adolescent ; Adult ; Arthroscopy ; Female ; Humans ; Knee Joint ; surgery ; Male ; Patellar Dislocation ; physiopathology ; surgery ; Patellar Ligament ; physiopathology ; surgery ; Patellofemoral Joint ; physiopathology ; surgery ; Range of Motion, Articular ; Treatment Outcome ; Young Adult

OBJECTIVETo study the effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty (TKA) demonstrated on autopsy specimens, as the guide for surgeons to choose the correct reference axis for rotational alignment of the femoral components and to reduce the patellofemoral joint complications.

METHODSSelect 9 frozen fresh human cadaver knees without gross deformities or instabilities and mount specimens on a patellofemoral joint testing jig connected to a Model 8501 Instron machine (Instron Corporation, Canton, MA). The study simulated the action of squatting from the standing position with the foot firmly planted. Standard TKA was performed in each specimen by the same senior surgeon using Nexgen LPS total knee system (Zimmer Corporation, Warsaw Indiana). Alter rotational alignment of the femoral components referenced to the transepicondylar axis and the Whiteside's line respectively. Measure biomechanics of the patellofemoral joints using Fuji prescale film at 30 degrees , 60 degrees , 90 degrees , 120 degrees of knee flexion respectively. The digital values were obtained by the handheld pressure measurement systems (FPD-305E, FPD-306E) and Autocad software.

RESULTSThe rotational alignment of the femoral components paralleled to the transepicondylar axis had the best results of the peak value of the patellofemoral contact pressure (P < 0.05). There were no statistically significant differences in patellofemoral contact area (P > 0.05). But the patellofemoral contact area had the close correlations to the angles of the knee flexion and the specimens.

CONCLUSIONSRotational alignment of the femoral components has a great influence on the patellofemoral contact pressure in total knee arthroplasty. It is reliable for surgeons to choose the transepicondylar axis as the reference axis to rotate femoral components.

Adult ; Arthroplasty, Replacement, Knee ; methods ; Biomechanical Phenomena ; Cadaver ; Humans ; Knee Joint ; physiopathology ; surgery ; Knee Prosthesis ; Middle Aged ; Rotation

Adult ; Ankylosis ; surgery ; Arthroscopes ; Female ; Humans ; Knee Joint ; physiopathology ; surgery ; Male ; Middle Aged

Adolescent ; Adult ; Female ; Fractures, Bone ; complications ; Humans ; Joint Diseases ; etiology ; physiopathology ; surgery ; Knee Joint ; physiopathology ; Male ; Middle Aged

OBJECTIVETo investigate the short-term clinical outcome of unicompartmental knee arthroplasty for the treatment of spontaneous osteonecrosis of the knee.

METHODSFrom September 2013 to April 2014,5 patients with spontaneous osteonecrosis of the knee underwent unicompartmental knee arthroplasty, included 3 males and 2 females, aged from 65 to 80 years old with an average of 74 years. The courses of disease was from 1 to 6 years with the mean of 3 years. According to the radiographic staging criteria of Koshino, 1 case was stage II, 2 cases were stage III, 2 cases were stage IV. Clinical effects were assessed by VAS score, HSS score, and knee range of motion, tibiofemoral angle before and after operation.

RESULTSAll the patients were followed up from 6 to 7 months with an average of 6.4 months. All incisions obtained primary healing, and there were no complications such as infection, thrombosis, fracture of lower limbs. All 5 patients' pain relieved and their knee function improved significantly after operation, but knee range of motion had no obviously improved. Postoperative HSS scores, VAS scores, tibiofemoral angle were significantly improved than that of preoperative.

CONCLUSIONThe short-term effect of unicompartmental knee arthroplasty in treating spontaneous osteonecrosis of the knee is satisfactory.

Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Knee ; methods ; Female ; Humans ; Joint Diseases ; physiopathology ; surgery ; Knee Joint ; Male ; Osteonecrosis ; physiopathology ; surgery ; Range of Motion, Articular

OBJECTIVETo investigate surgical procedure and clinical effects for the treatment of patellofemoral osteoarthritis (PFOA) with arthroscopic patelloplasty and circumpatellar denervation.

METHODSTotally 156 patients with PFOA (62 males and 94 females; aged from 45 to 61 years old with an average of 52) were treated from September 2011 and March 2013. The clinical manifestations included recurrent swelling and pains on knee-joint,and aggravated pains upon going up/down-stairs, squatting-down, or standing-up. PFOAs were treated with arthroscopic patelloplasty and circumpatellar denervation. The therapeutic effects before and after surgery were evaluated by Lysholm scores and Kujala scores. The therapeutic effects were graded by classification of cartilage injury degrees.

RESULTSTotally 149 cases were successfully followed up for 14.8 months. The incisions were healed well and no complication were occurred. Lysholm score was improved from 73.29 preoperatively to 80.93 postoperatively and average Kajala score from 68.34 preoperatively to 76.48 after surgery. This procedure was highly effective for patients with I - III degree cartilage injury, while not for patients with IV degree cartilage injury.

CONCLUSIONFor PFOA patients, arthroscopic patelloplasty and circumpatellar denervation is effective for significantly relieving anterior knee pains, improving knee-joint functions and quality of life, and deferring arthritic procession.

Arthroscopy ; Denervation ; Female ; Humans ; Knee Joint ; innervation ; surgery ; Male ; Middle Aged ; Osteoarthritis, Knee ; physiopathology ; surgery ; Range of Motion, Articular ; Treatment Outcome