Patellofemoral osteoarthritis after Insall’s proximal realignment for recurrent patellar dislocation

Purpose

The aim of the present study was to retrospectively investigate the development of patellofemoral osteoarthritis after the historical Insall’s proximal realignment for patellar stabilisation in patients with recurrent patellar dislocation. Furthermore, risk factors for recurrent patellar dislocation and for patellofemoral osteoarthritis development were evaluated.

Methods

Forty-two patients underwent patellofemoral stabilising surgery by the historic Insall’s proximal realignment; they were evaluated with a mean follow-up period of 52 months. Plain radiography was used to document osteoarthritic changes by using the Iwano classification. MRIs obtained at the latest follow-up were evaluated for patellofemoral cartilage lesions. Univariate and multivariate logistic regression analyses were performed to evaluate the influence of trochlear dysplasia, tibial tubercle–trochlear groove distance and patellar height on redislocation. Pearson’s χ ² and the Spearman’s correlation tests were used to assess a possible correlation between trochlear dysplasia and patellar dislocation, as well as between instability and development of patellofemoral osteoarthritis.

Results

At the latest follow-up, plain radiographs showed a significant increase in patellofemoral osteoarthritis (grades II–IV according to the Iwano classification) in 18 patients (43 %) compared with 4 patients (10 %) at the time of surgery (P = 0.001). Patellofemoral cartilage lesions (grades II–IV) were detected in 18 patients (43 %) on MRI. Nine patients (21 %) had at least one incidence of redislocation at follow-up. Estimated redislocation-associated risk factors could not be determined. Trochlear dysplasia had a significant impact on patellofemoral osteoarthritis development (P = 0.001), whereas recurrent patellar instability had none (n.s.).

Conclusion

Insall’s proximal realignment technique leads to a significant progression of patellofemoral osteoarthritis. No risk factors for redislocation could be found; however, the presence of trochlear dysplasia did correlate with patellofemoral osteoarthritis.

Level of evidence

IV.     

Patellar dislocations in children, adolescents and adults: A comparative MRI study of medial patellofemoral ligament injury patterns and trochlear groove anatomy

Purpose

The first aim was to compare medial patellofemoral ligament injury patterns in children and adolescents after first-time lateral patellar dislocations with the injury patterns in adults. The second aim was to evaluate the trochlear groove anatomy at different developmental stages of the growing knee joint.

Materials and methods

Knee magnetic resonance (MR) images were collected from 22 patients after first-time patellar dislocations. The patients were aged 14.2 years (a range of 11-15 years). The injury pattern of the medial patellofemoral ligament was analysed, and trochlear dysplasia was evaluated with regard to sulcus angle, trochlear depth and trochlear asymmetry. The control data consisted of MR images from 21 adult patients who were treated for first-time lateral patellar dislocation.

Results

After patellar dislocation, injury to the medial patellofemoral ligament was found in 90.2% of the children and in 100% of the adult patients. Injury patterns of the medial patellofemoral ligament were similar between the study group and the control group with regard to injury at the patellar attachment site (Type I), to the midsubstance (Type II) and to injury at the femoral origin (Type III) (all p > 0.05). Combined lesions (Type IV) were significantly less frequently observed in adults when compared to the study group (p = 0.02). The magnitude of trochlear dysplasia was similar in children, adolescents and adults with regard to all three of the measured parameter-values (all p > 0.05). In addition, the articular cartilage had a significant effect on the distal femur geometry in both paediatrics and adults.

Conclusion

First, the data from our study indicated that the paediatric medial patellofemoral ligament injury patterns, as seen on MR images, were similar to those in adults. Second, the trochlear groove anatomy and the magnitude of trochlear dysplasia, respectively, did not differ between adults and paediatrics with patellar instability. Thus, physicians are confronted with similar anatomical risk factors and similar injuries to the medial soft-tissue restraints in children when compared to adults with patellar instability.     

Patellofemoral arthroplasty: outcomes and factors associated with early progression of tibiofemoral arthritis

Purpose

The purpose of this study was to review the results of patellofemoral arthroplasty (PFA) performed by a single surgeon at a single institution in order to determine factors associated with clinical outcomes and progression of tibiofemoral degenerative joint disease.

Methods

Sixty-one patients with isolated patellofemoral osteoarthritis were treated with a PFA by a single surgeon between 2003 and 2009. Fifty-nine patients were available for analysis with a mean follow-up of 4 years (range 2–6 years). Patients were evaluated by measuring range of motion and with the use of the Knee Society clinical rating system, the Tegner Activity Level Scale, and the UCLA Activity Score. In addition, preoperative radiographs were evaluated for patellofemoral and tibiofemoral compartment osteoarthritis and presence of trochlear dysplasia, and post-operative radiographs were reviewed for progression of tibiofemoral degenerative arthritis. Furthermore, multivariate statistical methods were applied to study factors that had potential to influence the final outcome.

Results

There was no statistically significant association between age, gender, history of prior knee surgery, patellar height, patellofemoral osteoarthritis severity, patellar and femoral component size, or performance of lateral release with patient pain and function (as measured by the Knee Society scores) or progression of tibiofemoral joint osteoarthritis at final follow-up. Increased preoperative body mass index (BMI) was associated with lower post-operative Knee Society function scores (p = 0.03). Patients with preoperative trochlear dysplasia had significantly less radiographic evidence of tibiofemoral joint osteoarthritis progression compared with patients without trochlear dysplasia at final follow-up (p < 0.0001).

Conclusion

In this study, patients with preoperative radiographic evidence of trochlear dysplasia experienced less progression of tibiofemoral degenerative joint disease than patients without trochlear dysplasia at a mean follow-up of 4 years.

Level of evidence

IV.     

The inferomedial patellar protuberance and medial patellar ossicle in patellar instability

Purpose

The purpose of the study was to define the frequency of an inferomedial patellar protuberance in patients presenting to a specialist Patella Clinic and to characterise the clinical and radiological features as well the association between the inferomedial patellar protuberance and the medial patellar ossicle.

Methods

A cohort of 163 patients (166 knees) was reviewed from a prospectively collected clinical database and radiological imaging. This included a record of patellar tracking.

Results

An inferomedial patellar protuberance was found in 62 (37 %) knees. A medial patellar ossicle was noted in 56 (34 %) knees. In all, an inferomedial patellar protuberance or medial patellar ossicle or both was found in 90 (54 %) knees. The association between inferomedial patellar protuberance and significant trochlear dysplasia was highly significant (p = 0.01), but not for the medial patellar ossicle (n.s.). The presence of an inferomedial patellar protuberance was significantly less likely in patients with hypermobility syndrome (p = 0.001); however, there was no significant association between hypermobility syndrome and medial patellar ossicle (n.s.), or the presence of either or both an inferomedial patellar protuberance and medial patellar ossicle (n.s.). All patients with a clunk at 20°–30° flexion had significant trochlear dysplasia and an inferomedial patellar protuberance.

Conclusion

Radiological changes consistent with an inferomedial patellar protuberance were found in about one-third of patients presenting to a specialist Patella Clinic. Patellar maltracking and a clunk at 20°–30° flexion are associated with significant trochlear dysplasia plus an inferomedial patellar protuberance. If undertaking an operative correction, both deformities should be considered in order to avoid joint incongruity.

Level of evidence

III.

     

Is Percutaneous Transhepatic Biliary Drainage Better than Endoscopic Drainage in the Management of Jaundiced Patients Awaiting Pancreaticoduodenectomy? A Systematic Review and Meta-analysis

Purpose

To compare postoperative complications in patients who underwent pancreatoduodenectomy after either endoscopic or percutaneous biliary drain (BD).

Association of trochlear dysplasia with degenerative abnormalities in the knee: data from the Osteoarthritis Initiative

Objective

To evaluate trochlear morphology as a potential risk factor for patellofemoral osteoarthritis, determined by morphological and quantitative measurements of cartilage degeneration using 3-T magnetic resonance imaging (MRI) of the knee.

Materials and methods

MRI of the right knees of 304 randomly selected subjects, aged 45–60 years, from the Osteoarthritis Initiative (OAI) progression cohort were screened for trochlear dysplasia, defined by an abnormal trochlear depth. Out of 304 subjects, n?=?85 demonstrated a shallow trochlea (depth ≤3 mm; 28 %). In these, and also in a random sample of controls with normal trochlear depth (n?=?50), the facet ratio and the sulcus angle were calculated and knee structural abnormalities were assessed by using a modified Whole Organ MR Imaging Score (WORMS). Cartilage segmentation was performed and T₂ relaxation times and patellar cartilage volume were determined. ANOVA and multivariate regression models were used for statistical analysis of the association of MRI structural measures and trochlear morphology.

Results

Knees with a shallow trochlea showed higher patellofemoral degeneration (WORMS mean ± standard deviation, 11.2?±?0.5 versus 5.7?±?0.6; multivariate regression, P?<?0.001) and lower patellar cartilage volume than controls (900?±?664 mm³ versus 1,671?±?671 mm³; P?<?0.001). Knees with an abnormal medial-to-lateral facet ratio (<0.4) showed increased patellofemoral WORMS scores (12.3?±?0.9 versus 8.3?±?0.5; P?<?0.001). Knees with an abnormal sulcus angle (>170°) also showed increased WORMS scores (12.2?±?1.1 versus 8.6?±?0.6; P?=?0.003). T₂ values at the patella were significantly lower in the dysplasia group with a shallow trochlea. However, significance was lost after adjustment for cartilage volume (P?=?0.673).

Conclusion

Trochlear dysplasia, defined by a shallow trochlea, was associated with higher WORMS scores and lower cartilage volume, indicating more advanced osteoarthritis at the patellofemoral joint.     

Lateral displacement,sulcus angle and trochlear angle are associated with early patellofemoral osteoarthritis following anterior cruciate ligament reconstruction

Purpose

Patellofemoral osteoarthritis (PFOA) occurs in approximately half of anterior cruciate ligament (ACL)-injured knees within 10–15 years of trauma. Risk factors for post-traumatic PFOA are poorly understood. Patellofemoral alignment and trochlear morphology may be associated with PFOA following ACL reconstruction (ACLR), and understanding these relationships, particularly early in the post-surgical time period, may guide effective early intervention strategies. In this study, patellofemoral alignment and trochlear morphology were investigated in relation to radiographic features of early PFOA 1-year post-ACLR.

Methods

Participants (aged 18–50 years) had undergone ACLR approximately 1 year prior to being assessed. Early PFOA was defined as presence of a definite patellofemoral osteophyte on lateral or skyline radiograph. Sagittal and axial plane alignment and trochlear morphology were estimated using MRI. Using logistic regression, the relationship between alignment or morphology and presence of osteophytes was evaluated.

Results

Of 111 participants [age 30 ± 8.5; 41 (37%) women], 19 (17%) had definite osteophytes, only two of whom had had patellofemoral chondral lesions noted intra-operatively. One measure of patellar alignment (bisect offset OR 1.1 [95% confidence interval 1.0, 1.2]) and two measures of trochlear morphology (sulcus angle OR 1.1 [1.0, 1.2], trochlear angle OR 1.2 [1.0, 1.5]) were associated with patellofemoral osteophytes.

Conclusions

Patellofemoral malalignment and/or altered trochlear morphology were associated with PFOA 1 year following ACLR compared to individuals post-ACLR without these features. Clarifying the role of alignment and morphology in post-traumatic PFOA may contribute to improving early intervention strategies aimed at secondary prevention.

Level of evidence

IV.

     

Allowing one quadrant of patellar lateral translation during medial patellofemoral ligament reconstruction successfully limits maltracking without overconstraining the patella

Purpose

Graft tensioning during medial patellofemoral ligament (MPFL) reconstruction typically allows for lateral patellar translation within the trochlear groove. Computational simulation was performed to relate the allowed patellar translation to patellofemoral kinematics and contact pressures.

Methods

Multibody dynamic simulation models were developed to represent nine knees with patellar instability. Dual limb squatting was simulated representing the pre-operative condition and simulated MPFL reconstruction. The graft was tensioned to allow 10, 5, and 0 mm of patellar lateral translation at 30° of knee flexion. The patellofemoral contact pressure distribution was quantified using discrete element analysis.

Results

For the 5 and 10 mm conditions, patellar lateral shift decreased significantly at 0° and 20°. The 0 mm condition significantly decreased lateral shift for nearly all flexion angles. All graft conditions significantly decreased lateral tilt at 0°, with additional significant decreases for the 5 and 0 mm conditions. The 0 mm condition significantly increased the maximum medial pressure at multiple flexion angles, increasing by 57% at 30°, but did not alter the maximum lateral pressure.

Conclusions

Allowing 5 to 10 mm of patellar lateral translation limits lateral maltracking, thereby decreasing the risk of post-operative recurrent instability. Allowing no patellar translation during graft tensioning reduces maltracking further, but can overconstrain the patella, increasing the pressure applied to medial patellar cartilage already fibrillated or eroded from an instability episode.

     

Effects of upright weight bearing and the knee flexion angle on patellofemoral indices using magnetic resonance imaging in patients with patellofemoral instability

Purpose

This study analysed the effects of upright weight bearing and the knee flexion angle on patellofemoral indices, determined using magnetic resonance imaging (MRI), in patients with patellofemoral instability (PI).

Methods

Healthy volunteers (control group, n = 9) and PI patients (PI group, n = 16) were scanned in an open-configuration MRI scanner during upright weight bearing and supine non-weight bearing positions at full extension (0° flexion) and at 15°, 30°, and 45° flexion. Patellofemoral indices included the Insall–Salvati Index, Caton–Deschamp Index, and Patellotrochlear Index (PTI) to determine patellar height and the patellar tilt angle (PTA), bisect offset (BO), and the tibial tubercle–trochlear groove (TT–TG) distance to assess patellar rotation and translation with respect to the femur and alignment of the extensor mechanism.

Results

A significant interaction effect of weight bearing by flexion angle was observed for the PTI, PTA, and BO for subjects with PI. At full extension, post hoc pairwise comparisons revealed a significant effect of weight bearing on the indices, with increased patellar height and increased PTA and BO in the PI group. Except for the BO, no such changes were seen in the control group. Independent of weight bearing, flexing the knee caused the PTA, BO, and TT–TG distance to be significantly reduced.

Conclusions

Upright weight bearing and the knee flexion angle affected patellofemoral MRI indices in PI patients, with significantly increased values at full extension. The observations of this study provide a caution to be considered by professionals when treating PI patients. These patients should be evaluated clinically and radiographically at full extension and various flexion angles in context with quadriceps engagement.

Level of evidence

Explorative case–control study, Level III.

     

Anatomical factors influencing patellar tracking in the unstable patellofemoral joint

Purpose

The current study was performed to relate anatomical parameters to in vivo patellar tracking for pediatric patients with recurrent patellar instability.

Methods

Seven pediatric patients with recurrent patellar instability that failed conservative treatment were evaluated using computational reconstruction of in vivo patellofemoral function. Computational models were created from high-resolution MRI scans of the unloaded knee and lower-resolution scans during isometric knee extension at multiple flexion angles. Shape matching techniques were applied to replace the low-resolution models of the loaded knee with the high-resolution models. Patellar tracking was characterized by the bisect offset index (lateral shift) and lateral tilt. Anatomical parameters were characterized by the inclination of the lateral ridge of the trochlear groove, the tibial tuberosity–trochlear groove distance, the Insall–Salvati index and the Caton–Deschamps index. Stepwise multivariable linear regression analysis was used to relate patellar tracking to the anatomical parameters.

Results

The bisect offset index and lateral tilt were significantly correlated with the lateral trochlear inclination (p ≤ 0.002) and TT–TG distance (p < 0.05), but not the Insall–Salvati index or the Caton–Deschamps index. For both the bisect offset index and lateral tilt, the standardized beta coefficient, used to identify the best anatomical predictors of tracking, was larger for the lateral trochlear inclination than the TT–TG distance.

Conclusion

For this population, the strongest predictor of lateral maltracking that could lead to patellar instability was lateral trochlear inclination.

Level of evidence

Diagnostic study, Level II.     

Patellar tracking should be taken into account when measuring radiographic parameters for recurrent patellar instability

Purpose

To date, many radiographic parameters on patellar instability have their measurements taken statically, and have not been studied in various degrees of flexion according to the patellar tracking. There are also limited data regarding the use of these parameters in predicting recurrent patellar dislocation. The current study aims to review the radiographic parameters of the patellofemoral joint in different degrees of knee flexion and to correlate them with the presence of recurrent instability.

Methods

A 10-year retrospective study was conducted on all patients who had computed tomography patellar-tracking scan done for patellar instability when aged 18 years or younger. The computed tomography patellar-tracking scans were performed with the knee in extension, 10° flexion, and 20° flexion. The axial radiographic parameters were evaluated at the patellar equator, roman arch, and distal patellar pole. Sagittal and coronal parameters were noted. Radiographic parameters were then correlated with recurrent patellar instability.

Results

The femoral sulcus angle and trochlear groove depth at the distal patellar pole in 10° knee flexion (p value 0.04 and 0.03, respectively) and patellar equator in 20° knee flexion (p value 0.02 and 0.03, respectively) had the most significant clinical correlations with recurrent instability on multivariate analysis. Other radiographic parameters found to have significant clinical correlation on univariate analysis include the patellar tilt angle, congruence angle, femoral sulcus angle, trochlear groove depth, and Wiberg’s classification.

Conclusions

As per the knee dynamics, axial radiographic parameters had the most significant correlation with recurrent patellar instability when measured at the distal patellar pole in 10° knee flexion and at the patellar equator in 20° knee flexion. Future axial radiographic evaluation of patellofemoral instability should then be performed at these degrees of knee flexion and axial cuts. Trochlear dysplasia, as measured by the femoral sulcus angle and trochlear groove depth, was the most significant predictor of recurrent patellar instability in the skeletally immature. Wiberg’s classification was also a novel factor found to have clinical correlation with patellofemoral instability.

Level of evidence

III.

     

Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella

Purpose

The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis.

Methods

Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3–4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella–patellar tendon angle (P–PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P–PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P–PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis.

Results

The mean age of all participants was 52.9 ± 8.2 years. The mean P–PT angle was significantly lower in chondromalacia group (142.1° ± 3.6°) compared to control group (144.5° ± 5.3°) (p = 0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P–PT angles in patients with superior (141.8 ± 2.7) and inferior subgroups (139.2 ± 2.3) were significantly lower than the values in the control group (p < 0.05). The contact area values were detected higher in models with chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models.

Conclusion

This study revealed that sagittal plain malpositioning of the patellofemoral joint might be related to chondromalacia, especially in the presence of lesions in the upper and lower part of the patella. This condition leads to supraphysiological loadings on the patellofemoral joint. Sagittal patellar tilt should be considered in the evaluation and management of patellar cartilage defects. Taking sagittal plane malalignment into consideration in patellofemoral joint evaluation will enable us to design new physical and surgical modalities.

Level of evidence

IV.

     

Influence of tibial slope asymmetry on femoral rotation in patients with lateral patellar instability

Purpose

The geometry of the tibial plateau and its influence on the biomechanics of the tibiofemoral joint has gained increased significance. However, no quantitative data are available regarding the inclination of the medial and lateral tibial slope in patients with patellar instability. It was therefore the purpose of this study to evaluate tibial slope characteristics in patients with patellar dislocations and to assess the biomechanical effect of medial-to-lateral tibial slope asymmetry on lateral patellar instability.

Methods

Medial and lateral tibial slope was measured on knee magnetic resonance images in 107 patients and in 83 controls. The medial-to-lateral tibial slope asymmetry was assessed as the intra-individual difference between the medial and lateral tibial plateau inclination considering severity of trochlear dysplasia. The effect of tibial slope asymmetry on femoral rotation was calculated by means of radian measure.

Results

Severity of trochlear dysplasia was significantly associated with an asymmetric inclination of the tibial plateau. Whereas the medial tibial slope showed identical values between controls and study patients (n.s.), lateral tibial plateau inclination becomes flatter with increasing severity of trochlear dysplasia (p < 0.01). Consequently, the intra-individual tibial slope asymmetry increased steadily (p < 0.01) and increased internal femoral rotation in 20° and 90° of knee flexion angles in patients with severe trochlear dysplasia (p < 0.01). In addition, the extreme values of internal femoral rotation were more pronounced in patients with patellar instability, whereas the extreme values of external femoral rotation were more pronounced in control subjects (p = 0.024).

Conclusion

Data of this study indicate an association between tibial plateau configuration and internal femoral rotation in patients with lateral patellar instability and underlying trochlear dysplasia. Thereby, medial-to-lateral tibial slope asymmetry increased internal femoral rotation during knee flexion and therefore might aggravate the effect of femoral antetorsion in patients with patellar instability.

Level of evidence

III.     

The relationship between patellofemoral and tibiofemoral morphology and gait biomechanics following arthroscopic partial medial meniscectomy

Purpose

To examine the relationship between tibiofemoral and patellofemoral joint articular cartilage and subchondral bone in the medial and gait biomechanics following partial medial meniscectomy.

Methods

For this cross-sectional study, 122 patients aged 30–55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy, underwent gait analysis and MRI on the operated knee once for each sub-cohort of 3 months, 2 years, or 4 years post-surgery. Cartilage volume, cartilage defects, and bone size were assessed from the MRI using validated methods. The 1st peak in the knee adduction moment, knee adduction moment impulse, 1st peak in the knee flexion moment, knee extension range of motion, and the heel strike transient from the vertical ground reaction force trace were identified from the gait data.

Results

Increased knee stance phase range of motion was associated with decreased patella cartilage volume (B = ?17.9 (95 % CI ?35.4, ?0.4) p = 0.045) while knee adduction moment impulse was associated with increased medial tibial plateau area (B = 7.7 (95 % CI 0.9, 13.3) p = 0.025). A number of other variables approached significance.

Conclusions

Knee joint biomechanics exhibited by persons who had undergone arthroscopic partial meniscectomy gait may go some way to explaining the morphological degeneration observed at the patellofemoral and tibiofemoral compartments of the knee as patients progress from surgery.

Level of evidence

III.     

Combined trochleoplasty and MPFL reconstruction for treatment of chronic patellofemoral instability: a prospective minimum 2-year follow-up study

Purpose

Excessive trochlear dysplasia may be responsible for recurrent patellofemoral instability (PFI) due to a missing bony guidance for the patella in early flexion. Thus, an isolated medial patellofemoral ligament reconstruction (MPFLR) can be insufficient, since it mainly addresses instability close to extension and additionally can increase patellofemoral pressure leading to pain in flat or convex trochlear dysplasia. Therefore, in combination with a trochleoplasty, an anatomical trochlear groove is created, resulting in patellofemoral stability also in flexion, while patellofemoral pressure is normalized. In this prospective study, we evaluated the outcome of open trochleoplasty in combination with MPFLR with a minimum follow-up of 2 years for treatment of excessive PFI.

Methods

In between 2007 and 2009, 18 knees of 17 consecutive patients (mean age of 22.2 ± 4.9 years) with trochlear dysplasia type B, C or D according to Dejour et al. and positive apprehension from 0 to 60° of flexion were included. Tegner, Kujala and IKDC scores, apprehension and pain, trochlear dysplasia, sulcus angle, tibial tuberosity trochlear groove, patellar tilt and shift, Caton–Deschamps index as well as patellofemoral arthrosis according to the classification of Iwano et al. were assessed pre- and postoperatively.

Results

At a mean of 30.5 ± 5.9 months, all but one patient were subjectively satisfied with the outcome of the procedure, all showing absence of positive apprehension or redislocation. Significant (p < 0.001) reduction in pain (5.6 to 2.5 ± 2.8 points, VAS) and increase in Tegner (2, range 0–4 points to 6, range 3–8 points), Kujala (51.1 to 87.9 ± 20.0 points) and IKDC (49.5 to 80.2 ± 21.0 %) scores could be achieved. Radiologically significant (p < 0.02) improvement of patellofemoral positional parameters leading to more normal anatomy was recorded, while short-term arthrosis was absent.

Conclusions

Combined treatment for trochleoplasty with MPFLR serves as a successful therapy for chronic PFI. This combinatory treatment concept is a reliable option not only as salvage therapy but also as primary procedure regarding treatment for excessive PFI.

Level of evidence

Prospective case series, Level IV.     

The clinical and radiological results of individualized surgical treatment depending on pathologic abnormalities in recurrent patellar dislocation: low recurrence rate,but unintended patella baja

Purpose

To evaluate the clinical and radiological outcomes and chondral lesion change using individualized surgery for recurrent patellar dislocation.

Methods

A total of 31 knees with recurrent patellar dislocation underwent surgery depending on individual pathologic abnormalities. Pathologic abnormalities including medial laxity, lateral tightness, increased tibial tuberosity (TT)-to-trochlear groove distance (>20 mm), and patella alta (Caton–Deschamps ratio >1.2) were evaluated in each patient. The abnormalities were corrected through medial patellofemoral ligament reconstruction, TT distalization, TT anteromedialization, and lateral retinacula release. The mean follow-up period was 33 months.

Results

There was one recurrent case (3.2%), requiring additional surgery. The mean Kujala scores were significantly (P = 0.002) improved from 75.8 (SD 12.4) to 84.6 (SD 13.1). Tegner scores were significantly improved from 3.7 (range 1–9) to 5.4 (range 2–9) (P < 0.001), as were and visual analogue scale pain scores from 4.7 (SD 2.5) to 2.6 (SD 2.2) (P = 0.001). Caton–Deschamps ratio was significantly decreased from 1.1 (SD 0.2) to 0.9 (SD 0.1) (P < 0.001), regardless of TT distalization. Chondral lesions of the patella and trochlear groove were improved or maintained in 57.1 and 71.4% of patients, respectively.

Conclusion

Individualized surgery in recurrent patellar dislocation was effective and safe with a low recurrence rate. However, the possibility of unintended patella baja, which might be related to post-operative anterior knee pain, should be considered.

Level of evidence

IV.

     

Treatment of isolated patellofemoral osteoarthritis with lateral facetectomy plus Insall’s realignment procedure: long-term follow-up

Purpose

To assess the long-term results of lateral facetectomy plus Insall’s realignment procedure to treat isolated patellofemoral osteoarthritis.

Methods

All consecutive patients undergoing this procedure with a follow-up between 10 and 14 years were included in this study. Subjects were excluded if they had previous patellar dislocation, patellar fracture, tibiofemoral osteoarthritis (except mild cases) or follow-up <10 or >14 years. Failure cases (need for total knee arthroplasty) of this surgical procedure before 10 years of follow-up were considered in the overall failure rate. Clinical, functional and radiographic outcomes were obtained at baseline and compared to postoperative values.

Results

Forty-three patients (mean (SD) age 59.7 (8.1) years) had a follow-up between 10 and 14 years and were finally included in this study. The failure rate in the whole series and included patients was 26.4 and 16.3 %, respectively, for a mean (SD) follow-up of 9.2 (3.2) years and 11.7 (1.4) years, respectively. Patellofemoral pain (p < 0.0001), need for NSAIDs (p < 0.0001), longitudinal (p < 0.0001) and transversal (p < 0.0001) patellar glide tests, Zholen’s sign (p = 0.0007) and knee effusion (p = 0.02) significantly improved in the follow-up. Postoperative Knee Society Score (KSS) anatomical (p < 0.0001), functional (p < 0.0001) and total (p < 0.0001) scores and Kujala’s score (p = 0.001) were significantly higher compared to preoperative values. The patellar tilt (p = 0.001) and shift (p = 0.04) significantly improved postoperatively, whereas the patellofemoral osteoarthritis was not modified (n.s.) with respect to preoperative assessment.

Conclusions

The lateral facetectomy plus Insall’s realignment procedure was a successful treatment for isolated patellofemoral osteoarthritis from a clinical, functional and radiographic point of view in the long-term follow-up.

Level of evidence

Prospective case series, Level IV.     

Use of Breast Magnetic Resonance Imaging in Women Diagnosed With Atypical Ductal Hyperplasia at Core Needle Biopsy Helps Select Women for Surgical Excision

Purpose

The study sought to investigate the role of breast magnetic resonance imaging (MRI) in patients diagnosed with atypical ductal hyperplasia (ADH) at core needle biopsy (CNB).

Fast-Track Registration: A Way to Increase Efficiency in the IR Division

Purpose

To evaluate changes in patient registration process at an academic 2-suite IR Division to determine if moving registration from the waiting room to the vascular holding area decreased amount of time patients spent in the Radiology Department and improved start times.

Measurement of tibial tuberosity–trochlear groove distance: evaluation of inter- and intraobserver correlation dependent on the severity of trochlear dysplasia

Purpose

Excessive tibial tuberosity–trochlear groove distance (TT–TG) is considered as one of the major risk factors in patellofemoral instability (PFI). TT–TG characterises the lateralisation of the tibial tuberosity and the medialisation of the trochlear groove in the case of trochlear dysplasia. The aim of this study was to assess the inter- and intraobserver reliability of the measurement of TT–TG dependent on the grade of trochlear dysplasia.

Methods

Magnetic resonance imaging (MRI) scans of 99 consecutive knee joints were analysed retrospectively. Hereof, 61 knee joints presented with a history of PFI and 38 had no symptoms of PFI. After synopsis of the axial MRI scans with true lateral radiographs of the knee, the 61 knees presenting with PFI were assessed in terms of trochlear dysplasia. The knees were distributed according to the four-type classification system described by Dejour.

Results

Regarding interobserver correlation for the measurements of TT–TG in trochlear dysplasia, we found r = 0.89 (type A), r = 0.90 (type B), r = 0.74 (type C) and 0.62 (type D) for Pearson’s correlation coefficient. Regarding intraobserver correlation, we calculated r = 0.89 (type A), r = 0.91 (type B), r = 0.77 (type C) and r = 0.71 (type D), respectively. Pearson’s correlation coefficient for the measurement of TT–TG in normal knees resulted in r = 0.87 for interobserver correlation and r = 0.90 for intraobserver correlation.

Conclusion

Decreasing inter- and intraobserver correlation for the measurement of TT–TG with increasing severity of trochlear dysplasia was detected. In our opinion, the measurement of TT–TG is of significance in low-grade trochlear dysplasia. The final decision to perform a distal realignment procedure based on a pathological TT–TG in the presence of high-grade trochlear dysplasia should be reassessed properly.

Level of evidence

Retrospective study, Level II.