Objective To explore the effects of changes in the length of the patella on patellofemoral contact areas and pressures, to provide a theoretical foundation for treatment of lower pole of patella fracture. Methods Using homemadeloadingequipment, pressure sensitive films of 100 mm × 100 mm in size were placed on the force platform, vertically downwardload (0-19.6 N) was given. The pressure-sensitive response curve was obtained by computer image analysis of the pressuresensitive tablets and calculation. Six male left fresh knee specimens from voluntary donation were placed in homemade-test fixed load device, and the double-layer pressure sensitive film was placed on the patellofemoral joint surface; under loading of 196 N at flexion of 0, 15, 30, 45, 60, 75, 90, 105, 120, and 135° for 2 minutes, respectively, the pressure sensitive film was removed as the control group. Patellas were transected cut and in situ fixed by Kirschner wire and steel-wire as in situ fixation group. Bone fragments obtained from the corresponding 1/6 and 2/6 of contralateral patella, were embedded in the interspace between osteotomy with internal fixation with Kirschner wire and steel-wire respectively as lengthening group. Followed by the amputating patella length of 1/6, 2/6, 3/6 from proximal to distal and internal fixation with Kirschner wire and steel wire by turns as a shortening group. Repeat the above steps of each experiment. By image analysis the pressure sensitive film, the patella joint contact area were measured, and patellar contact pressure (including the peak pressure and average pressure) was calculated according to pressure-sensitive response curve. Results The actural contact area were significantly smaller in the shortening groups than in the control group at flexion of 30-135° (P lt; 0.05); the pressure was significantly bigger in shortening 1/6 group at flexion of 0, 15, 60, and 75°, in shortening 2/6 group at flexion of 0° and 75-135°, and in shortening 3/6 group at flexion of 0-30°and 75-135° than in the control group (P lt; 0.05); the peak pressure was significantly bigger in shortening 1/6 group at flexion of0, 15, and 60-105°, in shortening 2/6 group at flexion of 0, 15, and 75-105°, and in shortening 3/6 group at flexion of 0, 30, and 60-135° than in the control group (P lt; 0.05). The actural contact area was significantly smaller in the lengthening groups than in the control group at flexion of 15, 60, and 90°, and it was bigger at flexion of 105, 135° in lengthening 2/6 group than in the control group (P lt; 0.05); the pressure was significantly bigger in the lengthening groups at flexion of 15-75° than in the control group and it was smaller in the lengthening groups at flexion of 105, 135°, and smaller in lengthening 2/6 group at flexion of 120° (P lt; 0.05); the peak pressure was significantly smaller in lengthening 1/6 group than in the control group at flexion of 0, 90, and 105° and smaller in lengthening 2/6 group at flexion of 0° (P lt; 0.05). The actural contact area was significantly bigger in all lengthening groups than in all shortening groups at flexion of 30, 45, and 75-135° (P lt; 0.05). The pressure was significantly bigger in shortening 1/6 group than in lengthening groups at flexion of 0, 60, and 90° (P lt; 0.05), in shortening 2/6 group at flexion of 0, 60, and 90-120° (P lt; 0.05), in shortening 3/6 group at flexion of 0-135° (P lt; 0.05). The peak pressure was bigger in shortening groups than in lengthening 1/6 group at flexion of 0, 90, and 105° (P lt; 0.05), bigger than lengthening 2/6 group at flexion of 0° (P lt;0.05余请见正文.....
Objective To explore the treatment of patellofemoral joint disorders with radiofrequency vaporization under arthroscopy. Methods From June 2004 to June 2007, 86 cases of patellofemoral joint disorder (98 knees) were treated by lateral retinacular release or medial retinacular tighten added, and combined with bipolar radiofrequency chondroplastyunder arthroscopy. There were 30 males (34 knees) and 56 females (64 knees), aging 15-68 years (mean 40 years). The locations were left in 42 cases, right in 32 cases, both sides in 12 cases. The disease course was 3 months to 6 years (mean 30.5 months). In 98 knees, there were 28 knees of static patellar tilt, 10 knees of static patellar subluxation, 45 knees of dynamic patellar tilt and 15 knees of dynamic patellar subluxation. The Lysholm knee score preoperatively was 57.72 ± 8.86. Results The patellofemoral cartilage abnormal ity were classified according to the Outerbridge grade (18 knees of grade I, 36 knees of grade II, 32 knees of grade III and 12 knees of grade IV). The incisions healed by first intention without compl ications such as infection or hemarthrosis. Seventy-five cases (82 knees) were followed up 8-37 months (mean 20.6 months). One month after operation, the patellofemoral joint pain was rel ieved remarkably, the knee joint activity was good and the radiological outcomes was also satisfactory. Six months after operation, the Lysholm knee score was improved significantly in patients of grades I, II and III (P lt; 0.05), while there was no significant change in patients of grade IV (P gt; 0.05). The postoperative score was 69.95 ± 5.42 (P lt; 0.05). Conclusion Radiofrequency vaporization chondroplasty and soft tissue balance under arthroscopy are advantageous in terms of easy operation, less injury, sl ight reaction and have good effect on patellofemoral joint disorders.
Objective To summarize the strategies and treatment methods in correcting the maltracking of patellofemoral joints in the total knee arthroplasty (TKA). Methods From January 2000 to May 2007, the methods of releasing lateral retinaculum and tightening medial retinaculum of patellar, adjusting the position of the tibial prothesis properly and shifting the lateral 1/2 insertion inward to the medial side of patellar tendon, and reconstructing the patellar tendon insertion were used in correcting the maltracking of patellofemoral joints when the TKA was conducted for 49 knee joints of 48 cases. All thecases were females, aged 53-76 years old (66.8 on average). The course of disease was 6-23 years (16.2 years on average). Among all the cases, 37 with 38 knee joints were osteoarthritis, and 11 with 11 knee joints were arthritis pauperum. Different degrees of genu valgum and external rotation of knee joints were found in all cases. The genu valgum angle was 23-42° with an average of 33°. The Q angle was 16-23° with an average of 19°. Flexion deformity of knee joints with 8-35° (22° on average) was found in 23 cases. The preoperative KSS knee joint score was 21-51 points (32 points on average), and the function score was 29-45 points (33 points on average). Results All incisions obtained heal ing by first intension. All the patients were followed up for 7-82 months (52 months on average). Genu valgum deformity of knee joints was corrected in all cases. Residual flexion deformity with 5° of knee joints was found in 3 cases. The running track of patellofemoral joints returned to normal in all cases. Laceration or fragmentation was not found in reconstructed patellar l igaments. The postoperative KSS knee joint score was 76-89 points (82 points on average), and the function score was 81-90 points (85 points on average). The X-ray films from the very beginning of post-operation to the end of follow-up showed the prosthesis was normal. Conclusion In correcting the maltracking of patellofemoral joints in TKA, releasing lateral retinaculum and tightening medial retinaculum of patellar, adjusting the position of the tibial prothesis properly, shifting the lateral 1/2 insertion inward to the medial side of patellar tendon and reconstructing the patellar tendon insertion were efficient methods, without any adverse effect on the early rehabilitation training of knee joins.
ObjectiveTo investigate the value and feasibility of low-field MR in the diagnosis of excessive lateral pressure syndrome (ELPS) of the patellofemoral joint. MethodsThirty-seven patients confirmed to have ELPS by surgery or clinical examination between March 2010 and March 2013 were involved in this retrospective study. The injured knees of all patients were examined by SE sequence and Fat sequence, using Siemens 0.35 T MR scanner. The patella was assessed. Infrapatellar fat pad, patella tilt angle and patellofemoral joint space were measured. ResultsThere were 15 cases of type Ⅱ, 21 of type Ⅲ, and 1 of type Ⅳ knees. Three cases of bipartite were detected. Patella tilt angle: type Ⅳ > type Ⅲ > type Ⅱ. Infrapatellar fat pad had edema in 37 cases. And there were 29 cases of varying degrees of lateral patellar cartilage softening. ConclusionLow-field MRI is an effective diagnostic method of excessive lateral pressure syndrome for patellofemoral joint. STIR sequence is the best sequence for diagnosing patellofemoral excessive lateral pressure syndrome.
ObjectiveTo study the effect of the femoral tunnel position on the knee function recovery after medial patellofemoral ligament (MPFL) reconstruction. MethodsA retrospective analysis was made on the clinical date of 43 cases (43 knees) of recurrent patellar dislocation undergoing MPFL reconstruction and patellofemoral lateral retinaculum lysis between August 2013 and March 2014. There were 12 males and 31 females, aged 19.4 years on average (range, 9-35 years). All patients had trauma history and recurrent dislocations. The results of apprehesion test and J syndrom were positive. The patellar tilt test showed patellofemoral lateral retinaculum was tension. The effectiveness was evaluated using Lysholm knee functional score after operation. The distance from the center of the femoral tunnel to the femoral isometric point was measured on CT three dimensional reconstruction image. Whether the femoral tunnel position was isometric was evaluated. The correlation was analyzed between the distance from the center of the femoral tunnel to the femoral isometric point and Lysholm score. ResultsPrimary healing of incision was obtained in all patients. The patients were followed up 13-18 months (mean, 15 months). No patellar dislocation or subluxation occurred. The result of apprehensive test was negative. At last follow-up, the average Lysholm score was 93.8 (range, 83-100). The average distance from the center of the femoral tunnel to the femoral isometric point was 5.61 mm (range, 2-16 mm). The femoral tunnel position was isometric in 30 cases (69.8%) and non-isometric in 13 cases (30.2%). The distance from the center of the femoral tunnel to the femoral isometric point was negatively correlated with postoperative Lysholm score (r=-0.851, P=0.000). The postoperative Lysholm score was 95.7±2.3 in patients with isometric tunnel and was 89.4±3.5 in patients with non-isometric tunnel, showing significant difference (t=6.951, P=0.000). ConclusionFor patellofemoral joint instability, preparing the femoral isometric tunnel can establish a good foundation for the recovery of the knee function in MPFL reconstruction.
ObjectiveTo introduce the method of prior-localization femoral tunnel by using a special positioning tool under the C-arm radiographic machine before surgery, and to study the effect on the knee function recovery after medial patellofemoral ligament (MPFL) reconstruction.MethodsBetween January 2014 and January 2016, 32 patients with recurrent unilateral knee patellar dislocation were treated by arthroscopic patellofemoral lateral retinaculum release and MPFL reconstruction. The femoral tunnel position during MPFL reconstruction was prior-localizated under C-arm radiographic machine before operation. There were 8 males and 24 females, aged from 15 to 37 years, with an average of 23.8 years. The time from injury to admission ranged from 1 to 24 months, with an average of 9.7 months. Isometric point distance was measured on CT three-dimensional reconstruction image after operation to evaluate whether the position of femoral tunnel was isometric, and knee joint function was evaluated by Lysholm score. Spearman correlation analysis was performed between isometric point distance and Lysholm score.ResultsAll the 32 patients were followed up 12-18 months (mean, 14.2 months). No symptoms of patellar subluxation or dislocation was found during follow-up. Patellar extrapolation test and patellar extrapolation fear test were negative. The isometric point distance was 1.5-5.9 mm (mean, 3.44 mm) at 3 days after operation. All femoral tunnels were located in equidistant tunnels. At last follow-up, the Lysholm score of the patients was 92.8±2.1, which was significantly improved when compared with preoperative score (54.4±2.8) (t=61.911, P=0.000). Isometric point distance was negatively correlated with Lysholm score (r=–0.454, P=0.009).ConclusionC-arm radiographic machine can locate the femoral tunnel position of MPFL easily and accurately before operation. The short-term and medium-term effectiveness are satisfactory, and the ionizing radiation injury caused by multiple fluoroscopy during operation is avoided.
ObjectiveTo investigate the technique of optimizing the location of femoral attachment in medial patellofemoral ligament (MPFL) reconstruction assisted with arthroscopy and evaluate the effectiveness.MethodsBetween January 2014 and September 2018, 35 patients with patellar dislocation were admitted. There were 14 males and 21 females with an average age of 22.6 years (range, 16-38 years). All patients had a history of knee sprain. The disease duration ranged from 1 to 7 days (mean, 2.8 days). Patellar dislocation occurred 2-4 times (mean, 2.5 times). The preoperative Lysholm score and Kujala score were 47.60±11.24 and 48.37±9.79, respectively. The patellar congruence angle was (31.40±6.81)°, the patellar tilt angle was (29.95±5.44)°, the lateral patellofemoral angle was (−11.46±5.18)°, and the tibial tubercle-trochlear groove distance was (16.66±1.28) mm. All patients were treated by MPFL reconstruction with the semitendinosus tendon under arthroscopy. During operation, the suture anchors were inserted into the midpoint and the 1/3 point of superomedial edge of the patella. Then, the femoral tunnels were created in medial femoral condyle through limited excision. For tendon fixation, the Kirschner wires were inserted into adductor tubercle, medial epicondyle of femur, and the midpoint between the two points, as well as the anteriorly and posteriorly. Afterwards, the changes of ligament length and tension, patellar tracking, and the relationship of patella and femoral trochlea were evaluated, thereby determining the optimized femoral attachment for MPFL reconstruction. Finally, the patellar congruence angle, patellar tilt angle, and lateral patellofemoral angle were measured by imaging to assess the relationship of patella and femoral trochlea. Moreover, Lysholm score and Kujala score were used to evaluate the knee joint function.ResultsAll incisions healed by first intention without infection. All patients were followed up 12-18 months (mean, 15.4 months). At 12 months, the Lysholm score was 94.40±3.99 and the Kujala score was 92.28±4.13, which were significant higher than those before operation (P<0.05). No patellar dislocation occurred during follow-up. At 12 months, the patellar congruence angle was (6.57±4.59)°, the patellar tilt angle was (9.73±2.82)°, the lateral patellofemoral angle was (7.14±4.63)°, which were superior to those before operation (P<0.05).ConclusionDuring the MPFL reconstruction under arthroscopy, a higher positioning accuracy for the femoral attachment and satisfactory effectiveness can be obtained by evaluating MPFL length and tension, patellofemoral joint kinematics, and patellar tracking.