Lateral Shift Ratio Research Articles

Less risk of patellofemoral degeneration without significant clinical and survivorship difference for distal tibial tuberosity high tibial osteotomy compared to biplanar high tibial osteotomy over a mid-term follow-up.

This study aims to compare the mid-term radiographic, clinical results and survivorship between distal tibial tuberosity high tibial osteotomy (DTT-HTO) and conventional biplanar medial open-wedge high tibial osteotomy (cOW-HTO). The weight-bearing line ratio (WBL%) and medial proximal tibial angle (MPTA) were evaluated using a standing anteroposterior view of lower extremity. The posterior tibial slope (PTS), Caton-Deschamps index (CDI), tilting angle (TT) and lateral shift ratio (LSR) were evaluated using the lateral views and Merchant views. The Knee Society (KS) knee and function score, Lysholm score, and Anterior Knee Pain Scale (Kujala score) were were used to evaluate the functional outcomes. All parameters were evaluated preoperatively and at the final follow-up. The postoperative complications and survivorship for both groups were also evaluated during the follow-up period. The WBL% and MPTA exhibited no significant differences between the two groups preoperatively and at the final follow-up. The postoperative CDI and TT in the cOW group decreased significantly compared with the DTT group (p = .037 and .041, respectively). The PF grade showed a significant increase after DTT-HTO and cOW-HTO (p = .036 and <0.001, respectively). Furthermore, the postoperative PF grade of cOW group was significantly higher than that of DTT group (p = .039). The KS knee and function score, Lysholm score, and Kujala score for both groups improved similarly at the final follow-up. The survivorship free of revision was 92.7 % in the DTT group and 94.2% in the OW group. Despite observing a lower risk of PF joint progression in DTT-HTO compared to cOW-HTO, the clinical outcomes and survivorship after DTT-HTO and cOWHTO were comparable over a mid-term follow-up.

MPFL Reconstruction Combined with a Modified Elmslie-Trillat Procedure for Recurrent Patellofemoral Instability.

Several combined procedures have been reported for treating recurrent patellofemoral instability (RPI) with various types and severity of morphological abnormalities, but none have identified absolute threshold values as indications for surgery. We performed medial patellofemoral ligament (MPFL) reconstruction combined with a modified Elmslie-Trillat (ET) procedure on 24 knees (10 male and 11 female patients) to treat RPI with morphological abnormalities corresponding to elevated tibial tubercle-trochlear groove (TT-TG) distance, significant patella alta, and trochlear dysplasia. The inclusion criteria were RPI with morphological abnormalities corresponding to one or more of the following: sulcus angle > 160 degrees, trochlear dysplasia of Dejour classification C or D, Caton-Deschamps index > 1.5, lateral shift ratio > 50%, congruence angle > 15 degrees, or TT-TG distance > 20 mm, including habitual dislocation of the patella. Skeletally immature patients and those with congenital dislocation of the patella were excluded. The Kujala score, International Knee Documentation Committee subjective score, Knee Injury and Osteoarthritis Outcome score (KOOS), and each item of the KOOS improved significantly after surgery. Patellar apprehension sign was present preoperatively in all cases, but all disappeared postoperatively. No instance of postoperative redislocation was observed. On radiographic examination, the mean Q angle, tilting angle, lateral shift ratio, congruence angle, Caton-Deschamps index, Insall-Salvati index, and TT-TG distance improved significantly after surgery. There were no significant differences in sulcus angle after surgery. These results suggest MPFL reconstruction combined with a modified ET procedure provides satisfactory outcomes based on radiological and clinical evaluations for RPI with morphological abnormalities corresponding to elevated TT-TG distance, significant patella alta, and trochlear dysplasia.

Effect of the Inverted V-Shaped Osteotomy on Patellofemoral Joint and Tibial Morphometry as Compared With the Medial Opening Wedge High Tibial Osteotomy

Background: Recent studies have reported that medial opening wedge (OW) high tibial osteotomy (HTO) induces patella baja, resulting in degenerative changes in the patellofemoral joint. We have developed an inverted V-shaped (iV) HTO, which is classified as a neutral wedge osteotomy. Hypotheses: The study hypotheses were as follows: (1) patellar height, posterior tibial slope, and tibial length will not change between pre- and postoperative evaluations after iV-HTO; (2) the lateral shift ratio of the patella and the distance between the tibial tubercle and the trochlear groove may be significantly decreased after iV-HTO. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 191 patients (220 knees) who underwent HTO for medial osteoarthritis were enrolled retrospectively in this study: 107 knees underwent OW-HTO and 113 knees underwent iV-HTO. Clinical and radiological evaluations were performed before and at least 3 years after surgery. Results: Postoperatively, the mean Caton-Deschamps ratio was significantly decreased (P < .0001) from 0.95 to 0.79 in the OW group, while there were no significant changes in the iV group. The mean posterior tibial slope was significantly increased (P < .0001) from 8.5° to 10.5° in the OW group, while there were no significant differences in the iV group. Although the entire leg length was significantly increased (P < .0003) in both groups after HTO, there were no significant differences in tibial length between the pre- and postoperative periods in the iV group. Regarding the congruity of the patellofemoral joint, the mean lateral shift ratio did not significantly change in the OW group, whereas it was significantly decreased (P = .0012) from 11.5% to 8.8% in the iV group. The mean tibial tubercle–trochlear groove distance was significantly decreased (P < .0001) from 12.8 to 9.7 mm in the iV group, while it was significantly increased in the OW group (P < .0001). Concerning the clinical outcome, the Japanese Orthopaedic Association (JOA) and Lysholm knee scores at final follow-up (OW vs iV: JOA, 91.2 vs 90.1; Lysholm, 92.5 vs 89.0) were significantly increased (P < .0001) as compared with the preoperative values (OW vs iV: JOA, 68.3 vs 66.8; Lysholm, 67.9 vs 61.0). Conclusion: Patellar height, posterior tibial slope, and tibial length did not change after the iV-HTO, while they were significantly changed after the OW-HTO. Although the preoperative degrees of varus knee and patellofemoral osteoarthritis were more severe in the iV group than the OW group, the iV-HTO led to altered patellofemoral joint congruity.

No patella resurfacing total knee arthroplasty leads to reduction in the thickness of patellar cartilage to less than half within 5\u2009years: a quantitative longitudinal evaluation using MRI

PurposePatellar resurfacing in total knee arthroplasty (TKA) remains controversial as recent meta-analyses have not shown its clear superiority; however, most authors recommend it because it is associated with less frequent anterior knee pain and need for reoperation. We aimed to clarify the changes in patellar cartilage thickness in no patellar resurfacing TKA using a ceramic femoral component on magnetic resonance imaging (MRI).MethodsBetween 2009 and 2014, 40 consecutive patients (59 knees) were included in this study. All patients underwent TKA using zirconia ceramic femoral implants without patellar resurfacing. Indications for no patellar resurfacing TKA were absence of anterior knee pain, patellar compression pain, and osteoarthritic changes in the patellofemoral joint on plain radiography. The mean postoperative follow-up duration was 81.5 months (range, 25–131 months). Clinical and radiological evaluations were performed preoperatively and 5 years after TKA. Patellar cartilage thickness was evaluated preoperatively and every year for 5 years after TKA using MRI T2-weighted imaging. The patellar cartilage was divided into three regions of interest: medial, central, and lateral. To standardise the variation in patellar thickness among patients, the percent cartilage thickness was calculated.ResultsThe implant’s position was appropriate in all cases. Compared to preoperative scores, 5 years postoperatively, the Japanese Orthopedic Association score and Oxford knee score significantly improved from 52.1 to 84.7; mean tilting angle and congruence angle did not change significantly; mean lateral shift ratio significantly increased from 7.1% to 14.6%; cartilage thickness significantly decreased (P < 0.05); and the percentage cartilage thickness of the central, medial, and lateral cartilage zones gradually thinned to less than half. Four patients underwent conversion to patellar resurfacing due to anterior knee pain, without loosening the femoral and tibial implants.ConclusionThe patellar cartilage thickness decreased to less than half its preoperative level within 5 years after no patellar resurfacing TKA; this would led to clinical problems and conversion to patellar resurfacing.Level of evidenceLevel III.

Improved measure of workpiece surface deterioration during turning using non-contact vision method

The surface finish quality of a machined workpiece is commonly measured using the average roughness parameter, Ra. This parameter, however, is insensitive to the lateral changes undergone by the surface in the feed direction as a consequence of tool wear. In this work, the effectiveness of four methods of workpiece surface analysis, namely autocorrelation, cross-correlation, and two new methods, called lateral material shift (LMS) ratio and profile slope ratio (PSR) analyses are investigated. Dry machining experiments were carried out on 316 stainless steel. Images of tool nose and workpiece profiles were captured using digital camera, and the edges were extracted using sub-pixel edge detection. In the autocorrelation approach, each workpiece profile was correlated with a shifted version of the same profile. In the cross-correlation approach, the workpiece profiles at different stages of machining were correlated with a reference profile generated using the unworn tool edge. In the LMS ratio method, the material shift ratios were determined from each waveform on the workpiece profile at various stages of tool wear, while in the PSR method the slopes at the right and left part of the waveform were compared. Among the four methods, the LMS ratio method produced the best correlation with tool flank wear with the maximum R-squared value of 0.9461, while average roughness Ra showed no correlation at all with both major and nose flank wear.

Clinical outcomes after medial patellofemoral ligament reconstruction: an analysis of changes in the patellofemoral joint alignment.

Medial patellofemoral ligament (MPFL) reconstruction using the hamstring tendon is widely performed to treat recurrent patellar dislocation. MPFL reconstruction includes a post-operative process of necrosis and reperfusion of the hamstring tendon graft. We hypothesise that the patella gradually shifts laterally because of this process, ultimately affecting the patellofemoral joint alignment. This study aimed to analyse the chronological changes in the patellofemoral joint alignment and the outcomes of MPFL reconstruction. In this retrospective case-series study, the Knee Society, Lysholm, and Kujala scores were evaluated in 24 consecutive patients (27 knees). To evaluate patellar tracking defects, radiographic indices including the tilting angle, the lateral shift ratio, and the congruence angle were measured before, immediately after, and three, 12, and 36 months after MPFL reconstruction. Post-operative Kujala, KneeSociety, and Lysholm scores for the study population significantly improved relative to the pre-operative scores. The tilting and congruence angles at threemonths after the operation significantly increased relative to those recorded immediately after the operation. The tilting and congruence angles were not significantly different at three, 12, and 36 months after the operation. The post-operative outcomes of MPFL reconstruction for recurrent patellar dislocation were favourable. Insufficient union between the bone tunnel and tendon graft, along with an elongation of the necrotic tendon graft, may change the alignment of the patellofemoral joint within threemonths after the operation. Therefore, we believe it is necessary to refrain from knee rotation that places lateral stress on the patella until threemonths after the operation.

Middle-to long-term outcome after medial patellofemoral ligament reconstruction with Insall’s proximal realignment for patellar instability

BackgroundRecently, medial patellofemoral ligament (MPFL) reconstruction has become a common, widely used procedure to treat patellar instability. However, few reports exist on the long-term outcome after MPFL reconstruction. We elucidated the middle- to long-term outcome after MPFL reconstruction with Insall’s proximal realignment. Methods: From 1999 to 2012, 42 knees of 32 patients who underwent MPFL reconstruction with Insall’s proximal realignment were reviewed with a minimum follow-up of five years. Patients who could visit our office and receive some designated examinations were included in this study. The re-dislocation rate and patellar apprehension sign postoperatively were evaluated. The Kujala score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were calculated. We assessed the images using plane x-ray and magnetic resonance imaging (MRI). The tilting angle (TA), congruence angle (CA), and lateral shift ratio (LSR) on the plane x-ray were measured pre- and postoperatively and at final follow-up. Using MRI, osteochondral lesions at the patellofemoral joint were evaluated. ResultsA total of 20 knees of 15 patients (two male, 13 female) who could visit our office were studied. The follow-up rate was 47.6%. The mean age at operation was 19.9 (11–41) years and mean follow-up was 123 (60–215) months. One knee (5.5%) had a history of postoperative subluxation, and five (25%) had a positive apprehension sign. The mean Kujala score significantly improved from 65.5 to 86.1 points (P < 0.05). The mean KOOS (symptom, pain, activities of daily living [ADL], sports, quality of life [QOL]) was 74.4, 92.4, 97.3, 84.1, and 73.2 points, respectively, at final follow-up. On the plane x-ray, patellofemoral alignment was improved postoperatively, and this improvement was maintained at final follow-up. On MRI, in five of 20 cases, the patellofemoral osteoarthritic change was observed at final follow-up. However, in four of these five knees with severe osteochondral lesions, osteochondral fixation or transplantation surgery had been performed. Only one of the remaining 15 knees had a patellofemoral osteoarthritic change observed at final follow-up. ConclusionMiddle- to long-term outcome after MPFL reconstruction with Insall’s proximal realignment at our institution was evaluated, and good clinical results were observed. Most patients who did not have a severe cartilage lesion preoperatively did not develop osteoarthritic change.

Long-term clinical results of the crosse de hockey procedure for recurrent patellar dislocation.

A gold standard procedure has not been established for recurrent patellar dislocation because of multifactorial etiologies. We have been performing crosse de hockey procedure, which is a combination of medial and anterior transfer of the tibial tuberosity, in our institution since 1993. This study aimed to investigate the long-term clinical results of this procedure. A total of 19 patients (21 knees) underwent the crosse de hockey procedure for recurrent patellar dislocation. Of these patients, four were lost to follow-up. The remaining 17 knees in 15 patients (5 male and 10 female) were included in this study. The mean follow-up period was 13.2 years (range: 5-22.6 years). Clinical evaluation was performed using the Kujala score. Radiographic indicators, such as modified Insall-Salvati ratio, sulcus angle, congruence angle, tilting angle, lateral shift ratio, and the progression of patellofemoral osteoarthritis (OA), were measured. Positive apprehension sign and redislocation were not observed in any of the patients. The mean Kujala score was significantly improved from 36.5 ± 18.0 preoperatively to 92.6 ± 9.9 at the final follow-up. Definite OA (a grade 2 or more using the Iwano grading system) was not observed in the patellofemoral joint at the final follow-up. The crosse de hockey procedure showed satisfactory long-term clinical results for recurrent patellar dislocation. This procedure could prevent the progression of patellofemoral OA because of the unloading effect of the patellofemoral joint by anteromedial transfer of the tibial tuberosity.

Patellofemoral Osteoarthritis Progression and Alignment Changes after Open-Wedge High Tibial Osteotomy Do Not Affect Clinical Outcomes at Mid-term Follow-up

To evaluate the clinical and radiological outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess whether patellofemoral osteoarthritis (OA) progression and alignment changes after OWHTO affect clinical outcomes. Inclusion criteria were consecutive patients who underwent OWHTO from March 2005 to September 2013. Exclusion criteria were loss to follow-up within 2years and absence of second-look arthroscopy findings at the time of plate removal. The clinical parameters, including anterior knee pain while climbing stairs, Japanese Orthopedic Association score, and Oxford Knee Score, were evaluated. Radiological outcomes, including weight-bearing line ratio, modified Blackburne-Peel ratio, posterior tibial slope, tilting angle, lateral shift ratio, and patellofemoral OA (Kellgren-Lawrence grade), were evaluated preoperatively and at the final follow-up. Cartilage status (International Cartilage Repair Society grade) was evaluated at the initial HTO and at plate removal. Fifty-three patients (60 knees) were included in this study. The mean follow-up was 58.2 ± 22.4months. Two knees (3%) presented with mild anterior knee pain after OWHTO. The mean Japanese Orthopedic Association score (66.9 ± 11.2 to 91.2 ± 9.7) significantly improved (P < .001), and the mean Oxford Knee Score at the final follow-up was 42.0 ± 5.3. The mean modified Blackburne-Peel ratio (0.9 ± 0.1 to 0.7 ± 0.1, P < .001) and tilting angle (6.8 ± 3.7 to 5.6 ± 3.4, P= .033) significantly decreased after OWHTO, whereas no significant changes in posterior tibial slope (P= .511) and lateral shift ratio (P= .522) were observed. Radiologically, patellofemoral OA had progressed in 15 knees (27%), and arthroscopically patellofemoral cartilage degeneration had progressed in 27 knees (45%). However, there was no significant correlation between changes in patellofemoral alignment and clinical outcomes. Changes in patellofemoral alignment and patellofemoral OA progression did not affect the clinical outcomes of OWHTO at mid-term follow-up. Level IV, therapeutic case series.

Modified Elmslie-Trillat Procedure for Recurrent Dislocation of the Patella.

Many groups have reported good to excellent clinical outcomes of the Elmslie-Trillat (ET) procedure for recurrent dislocation of the patella. However, the mean follow-up period of these studies was no more than 5 years. We hypothesized that the long-term postoperative outcomes of the modified ET procedure for recurrent dislocation of the patella would be acceptable compared with those of other procedures. The long-term postoperative outcomes of patients treated with the modified ET procedure were examined. A total of 31 knees in 27 patients with recurrent dislocation of the patella who underwent a modified ET procedure (without medial capsular plication) were evaluated. The mean follow-up period was 13.0 years. Pre- and postoperative radiographs were examined to determine the Q-angle, tilting angle, lateral shift ratio, sulcus angle, congruence angle, and Insall-Salvati index. Clinical outcomes were evaluated based on the Fulkerson patellofemoral joint evaluation score, Kujala score, and the presence of the apprehension sign. Radiological evaluation revealed significant postoperative improvements in the Q-angle, tilting angle, lateral shift ratio, congruence angle, Kujala score, and Fulkerson score (p < 0.001). Sixty-eight percent of all patients had a "good" or "excellent" Fulkerson score. The apprehension sign continued to be shown for six knees. Progression of osteoarthritic changes was observed in three knees, and one knee was symptomatic. The modified ET procedure provided satisfactory outcomes based on radiological and clinical evaluations. These results show the long-term effectiveness and safety of the modified ET procedure for recurrent patellar dislocation.

Surgical versus Nonsurgical Treatments of Acute Primary Patellar Dislocation with Special Emphasis on the MPFL Injury Patterns.

The objective of the present study was to compare the clinical results of the surgical versus nonsurgical treatments of acute primary patellar dislocations with a medial patellofemoral ligament (MPFL) injury in the nonoverlap region with the vastus medialis oblique. In this study, 62 patients with an acute patellar dislocation and a concurrent MPFL injury in the nonoverlap region were randomly divided into two groups based on their birth years (even vs. odd years) and received either surgical or nonsurgical treatment. Of the 62 eligible patients, 30 were in the nonsurgical treatment group (Group 1) and 32 were in the surgical group (Group 2). Patellar stability tests and the Kujala knee questionnaire were performed, and radiographs were evaluated for patellar tilt and the lateral shift ratio by two blinded investigators. An osteochondral injury was noted in six (23.1%) patients from Group 1 and five (16.7%) patients from Group 2, with no statistical difference between the two groups. The mean Kujala score was 80.19 ± 5.07 and 93.57 ± 4.03 (p < 0.001) between the surgical and nonsurgical groups, respectively. The mean patellar tilt was 8.96 ± 1.64 and 6.83 ± 1.44 degrees (p < 0.001) and the lateral shift ratio was 11.08 ± 1.99 and 9.23 ± 1.96 (p = 0.001) between the surgical and nonsurgical groups, respectively. This study showed that the surgical treatment of MPFL injuries in the nonoverlap region achieved better clinical outcomes and improved subjective knee function compared with conservative therapy. Surgery should therefore be considered as the treatment of choice for these specific injuries.

Quantitative stress radiography of the patella and evaluation of patellar laxity before and after lateral release for recurrent dislocation patella

The aims of the present controlled clinical study were to (1) compare patella laxity determined in the outpatient clinic with that in anaesthetized patients and (2) evaluate patella laxity before and after lateral release. The study evaluated data on 33 knees from 33 patients (average age 19.7years) between 2007 and 2011. All patients were diagnosed with recurrent dislocation of the patella. Patellar stability was evaluated in each patient thrice: patellas were first imaged in the outpatient clinic prior to surgery at 45° knee flexion with 20N stress from the medial to lateral side and from the lateral to medial side; then, at the time of surgery, patella stress images were obtained in the same manner before and after the lateral release procedure. Radiological assessments were performed using the medial stress shift ratio (MSSR) and lateral stress shift ratio (LSSR). There were no significant differences in the LSSR and MSSR before surgery (outpatient data) and in anaesthetized patients before the lateral release procedure. Furthermore, there was no significant difference in MSSR at the time of surgery before and after the lateral release procedure. However, LSSR increased significantly after the lateral release procedure. The results of the present study suggest that quantitative patella stress radiography in the outpatient clinic is useful when it comes to investigating laxity of the patella, and that lateral release significantly increases lateral, but not medial, laxity in patients with recurrent patellar dislocation. IV.

Effectiveness and limitations of reconstruction of the medial patellofemoral ligament using a titanium interference screw in single patellar and femoral bone tunnels

No standard surgical procedure for medial patellofemoral ligament (MPFL) reconstruction exists. The purpose of this study was to evaluate the clinical effectiveness and limitation of the reconstructions of the MPFL in single patellar and femoral bone tunnels. The methods used a hamstring tendon and titanium interference screws in patients with recurrent patellar dislocation. Nineteen knees in 17 patients were studied. Subjects underwent MPFL reconstruction with or without lateral release using interference screws in single patellar and femoral tunnels. Patients were evaluated using preoperative and postoperative physical and radiographic examinations, including apprehension testing, assessment of tilting and congruence angles, medial and lateral shift ratios under stress X-ray imaging, and Kujala and Lysholm scores. Average follow-up was 22 months (12–71 months). None experienced recurrent postoperative episodes of dislocation or subluxation. By the final follow-up, patellar apprehension had disappeared in all patients except for one with generalized joint laxity. In addition, patients showed significant improvement in the following areas: tilting angle (from 14.4 ± 5.6° to 6.4 ± 4.6°, p < 0.0001), congruence angle (0.5 ± 16° to −9.2 ± 6.9°, p < 0.001), lateral shift ratio (23.8 ± 11.3% to 11.6 ± 13.4%, p < 0.001), Kujala score (74.0 ± 7.8 points to 95.7 ± 4.4 points, p < 0.0001), and Lysholm score (71.0 ± 10 points to 95.5 ± 5.3 points, p < 0.0001). MPFL reconstruction methods, using titanium interference screws in single patellar and femoral tunnels provide acceptable short-term results for the treatment of recurrent patellar dislocations.

A “sandwich” method of reconstruction of the medial patellofemoral ligament using a titanium interference screw for patellar instability in skeletally immature patients

No standard surgical procedure for medial patellofemoral ligament (MPFL) reconstruction exists in skeletally immature patients with patellar instability. This study aimed to evaluate the clinical effectiveness of a novel reconstruction technique for the MPFL in patients with patellar instability because of non-closure of the epiphyseal line. The "sandwich" method was fixation of the patella between a double-stranded semitendinosus tendon through the posterior third of the femoral insertion of the medial collateral ligament (MCL) as a pulley with a titanium interference screw in a single patellar tunnel. Five knees in five patients were studied: four with recurrent and one with habitual patellar dislocations. Subjects underwent MPFL reconstruction with or without lateral release. Patients were evaluated using pre-operative and post-operative physical and radiographic examinations, including apprehension testing, assessment of tilting and congruence angles, medial and lateral shift ratios under stress measured using X-ray imaging, and Kujala and Lysholm scores. No patient experienced recurrent post-operative episodes of dislocation or subluxation. By the final follow-up, patellar apprehension had disappeared in all patients. In addition, all patients showed significant improvement in the following: tilting angle, congruence angle, lateral shift ratio, Kujala score, and Lysholm score. The MPFL reconstruction methods, using a double-stranded semitendinosus autograft and sparing the femoral physeal line in non-closure of the epiphyseal line, provide acceptable short-term results for the treatment of patellar instability.

Patellar Articular Surface Replacement in Total Hip Arthroplasty

Examination of 249 patients with unilateral coxarthrosis was performed after total knee arthroplasty with (group 1) and without (group 2) patellar resurfacing performed at orthopaedic department of National Medical Surgical Center named after N.I. Pirogov. Total arthroplasty outcomes were assessed using knee-specific Oxford Knee Score (OKS), general questionnaire Medical Outcome Study 36-item Short-Form Health Survey (MOS Sf-36) and patellofemoral-specific questionnaire (PFQ). The following indications to patellar resurfacing were determined: body weight over 95 kg, patellar lateral shift ratio over 9%, 3rd and 4th degree of patellar chondromalacia by Outerbridge. Outcomes of patellar resurfacing were independent of patellar tilt angle (б), Insall-Salvati index, patient's height, body mass index, 1st and 2nd degree of patellar chondromalacia by Outerbridge.

Comparison of clinical results between an isometric and an anatomic technique for medial patellofemoral ligament reconstruction

To compare the clinical results of single-stranded isometric with double-stranded anatomic reconstruction of medial patellofemoral ligament (MPFL) for recurrent patellar dislocation. Retrospective analysis of 60 consecutive patients (72 knees) with recurrent patellar dislocation underwent medial patellofemoral ligament reconstruction between August 2004 and October 2008, 22 cases (27 knees) with single-stranded isometric reconstruction, 38 cases (45 knees) with double-stranded anatomic reconstruction. Postoperatively patellar stability was examined, and recurrent rate was recorded. Patellar lateral shift ratio and tilt were measured on CT scans. Knee function was evaluated with subjective questionnaire and the Kujala score. All patients were followed up for more than 12 months without recurrent redislocation. (1) Recurrent instability rate was 18.5% in single-stranded group and 2.2% in double-stranded group, with statistical difference (P < 0.05). (2) The patellar tilt and lateral shift ratio returned to normal, without statistical difference between groups (P > 0.05). (3) The Kujala score were 59 ± 9 and 62 ± 9 preoperatively and 87 ± 4 and 94 ± 6 postoperatively in single- and double-stranded group, with statistical difference (P < 0.05). (4) The excellect rate was 85.2% in single-stranded group, 97.8% in double-stranded group, with statistical difference(P < 0.05). Both reconstruction can improve patellar stability and knee function significantly, with double-stranded anatomic reconstruction better in clinic evaluation.

A long-term follow-up study after medial patellofemoral ligament reconstruction using the transferred semitendinosus tendon for patellar dislocation

The management of patellar dislocation syndrome has traditionally been difficult. There are no golden standard methods for patellar dislocations probably due to the many etiologies. However, it is known that medial patellofemoral ligament (MPFL) is damaged when the patella is dislocated. The purpose of this study is to examine whether our method of MPFL reconstruction is useful for the treatment of dislocated patellae and unstable patellae. Forty-six knees (43 patients) of 68 knees (65 patients) that were operated on using our surgical procedure for MPFL reconstruction with the advancement of the vastus medialis or the MPFL reconstruction with Insall's procedure were followed up for at least 5 years. The patient age ranged from 6 to 43 years. These knees consisted of six habitual dislocation patellae, twenty-six recurrent dislocation patellae, ten traumatic dislocation patellae, and four unstable patellae. The patients were evaluated pre-operatively and more than three times post-operatively at 6, 12, 36, 60, or 120 months. No patient experienced patellar dislocation after surgery. Their post-operative Kujala's scores were significantly improved. On conventional X-ray and on stress X-ray evaluations, the mean values for congruence angle, tilting angle, lateral shift ratio, medial stress shift ratio, and lateral stress shift ratio at the final follow-up (60 or 120 months) were demonstrated to be within the normal range. We conclude that our MPFL reconstruction method with the advancement of the vastus medialis or with Insall's procedure might be recommended for the treatment of habitual, recurrent, and indeed any other type of patellar dislocation, as well as for unstable patellae.

小児の膝蓋骨脱臼に対する半けん様筋けん移行術（上崎法）の成績

We reviewed the results of 15 knees in 11 patients who underwent semitendinosus transfer (Uezaki's procedure) at Fukuoka Chilyden's Hospital and Medical Center from 1983 to 1996. Five patellae were permanent dislocations, 2 were recurrent and 8 were habitual. The mean age at the time of the operation was 8.1 years, and we examined the results after an average follow-up period of 5.3 years.According to our own clinical evaluation methods, the results were satisfactory in 12 knees and unsatisfactory in 3 knees.We examined the sulcus angle, tilting angle, congruence angle and the lateral shift ratio on X-rays. Most angles and ratios decreased except in the 3 unsatisfactory cases.In the 4 unilateral cases, we found that the earlier surgical reduction was performed on the patella, the better the improvement in the shape of the sulcus of the patellar groove.For the purpose of earlier diagnosis, we examined patello-femoral congruity on MRI scans of 1 case with nail-patella syndrome whose patella was not able to be viewed on X-rays.We concluded early diagnosis and operative reduction was extremely important for the treatment of dislocation of the patella in children.

ＴＫＡ術後の膝蓋大腿関節障害の検討

We reviewed the patellofemoral problems of patients who received Mark 3 type total knee arthroplasty (TKA). There were 99 knee joints including 39 osteoarthrosis (OA) and 60 rheumatoid arthritis (RA) patients. Radiograms of all knees were reviewed. In 45 knee joints, clinical examination and radiological measurement were done and JOA scores before and after surgery were compared. The lateral shift ratio was calculated and the thickness of the patella was measured from the skyline view.There were two patella fractures. One fracture might be attributed to strenuous work as a farmer, and the other might be due to severe osteoporosis with ankylosis in the contralateral knee. Neither patella dislocation nor broken patella component were seen these 99 knees.Anterior knee pain appeared in only two out of 45 knees. Mean JOA score improved after TKA both in OA (preop. 44, post op. 71) and in RA knees (preop. 33, post op. 72). All 45 knees showed lateral shift of the patella. However, this did not indicate a poor result.There was no correlation between JOA score and the lateral shift ratio nor between JOA score and thickness of the patella.