Patellofemoral crepitus and clunk syndrome are infrequent, yet troublesome complications of total knee arthroplasty with a reported incidence of 0%-18%. They are primarily associated with implantation of posterior cruciate substituting designs. These entities are the result of peripatellar fibrosynovial hyperplasia at the junction of the superior pole of the patella and the distal quadriceps tendon which becomes entrapped within the superior aspect of the intercondylar box of the femoral component during knee flexion. When the knee extends, a crepitant sensation occurs as the fibrosynovial tissue exits the intercondylar box. Numerous etiologies have been proposed such as femoral component designs with a high intercondylar box ratio, previous knee surgery, reduced patellar tendon length, thinner patellar components, reduced patella-patellar component composite thickness, and smaller femoral components. Preventative measures include choice of femoral components with a reduced intercondylar box ratio, use of thicker patellar components, avoidance of over-resection of the patella, and debridement of the fibrosynovial tissue at the time of knee arthroplasty. Most patients with crepitus are unaware of the problem or have minimal symptoms so that no treatment is required. If significant disability is incurred, symptoms can be eliminated in a high percentage of patients with arthroscopic debridement of the fibrosynovial hyperplasia.
Arthralgia/etiology ; Arthroplasty, Replacement, Knee/*adverse effects ; Humans ; Knee Joint/*physiopathology ; Patellofemoral Joint/*physiopathology ; Postoperative Complications/etiology/physiopathology/prevention & control

A case of swelling and anterior painful knee due to tear of mediopatellar plica is reported. The patient also felt clunk of the patellofemoral joint and knee locking. Under arthroscopic examination, a thick and fibrous plica was found medial to patellar, and a bucket tear along the plica from medial patellar retinaculum to infrapatellar fat pad. Polarized microscopic examination showed collagen fiber fragment and loss of light reflecting property. Neuro-immunohistology suggested up-regulation of synovial plica innervation in the area around the crack. This may be related to the pain. The bucket tear of mediopatellar plica-caused pain and lock of knee are more common than previously reported.
Adult ; Arthroscopy ; Humans ; Knee Injuries ; physiopathology ; Male ; Pain ; etiology ; Patellofemoral Joint ; injuries

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

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 the incidence rate of anterior knee pain after total knee arthroplasty (TKA) and identify the related factors.

METHODSThis prospective, double-blind clinical trial involved a total of 128 patients scheduled for primary ipsilateral cemented three-component TKA for osteoarthrosis. The patients were randomized into two groups to receive operations for TKA with patellar resurfacing (experimental group) or not (control). The incidence of anterior knee pain was observed in these patients and the factor affecting the occurrence of anterior knee pain and knee was analyzed.

RESULTSThe patients were followed up for a mean of 16.5 months (range 6~24 months). The incidence rate of anterior knee pain was 10.9% (7/64) in the experimental group, showing no significant difference from the rate of 14.1% (9/64) in the control group. But the 52 patients with varus or valgus knee showed a significantly higher incidence rate of anterior knee pain (21.2%, 11/52).

CONCLUSIONTKA with patellar resurfacing can not decrease the incidence of anterior knee pain, and varus or valgus before the operation is associated with a higher risk of anterior knee pain.

Aged ; Arthroplasty, Replacement, Knee ; adverse effects ; methods ; China ; epidemiology ; Denervation ; methods ; Double-Blind Method ; Female ; Humans ; Knee Joint ; blood supply ; Male ; Middle Aged ; Osteoarthritis, Knee ; surgery ; Patella ; surgery ; Patellofemoral Pain Syndrome ; epidemiology ; etiology ; physiopathology ; Risk Factors