Recurrent patellar dislocation in adolescents: medial retinaculum plication versus vastus medialis plasty

Double Level Knee Derotational Osteotomy Yields Better Postoperative Outcomes than Tibial Tubercle Transfer Combined with Medial Patellofemoral Ligament Reconstruction in Patients with Recurrent Patellar Instability and Severe Malrotation

PURPOSE

To assess the postoperative outcomes of double level knee derotational osteotomy (KDRO) combined with medial patellofemoral ligament reconstruction (MPFLR), and to compare it with tibial tuber transfer (TTT) and MPFLR without derotational osteotomy in patients with recurrent patellar instability (RPI) and a marked torsional deformity.

METHODS

From March 2020 to December 2021, patients with torsion deformity (combined femoral torsion and tibial torsion ≥ 30°) were retrospectively included. The minimum follow-up time was 18 months. Patients received KDRO and MPFLR were categorized into KDRO group and patients received a combined TTT and MPFLR were categorized into control group. Preoperative and postoperative clinical symptoms, patient-reported outcomes (PROs) (Kujala, visual analogue scale [VAS], Lysholm, International Knee Documentation Committee [IKDC], Tegner, and Knee Injury and Osteoarthritis Outcome [KOOS] scores) and imaging parameters (femoral torsion, tibial torsion, patellar height, femoral trochlear dysplasia, congruence angle, patellar tilt angle, lateral patellar angle, lateral patellar translation, and tibial tubercle-trochlear groove distance) were analyzed.

RESULTS

In all, 36 patients were included with 18 in KDRO group and 18 in control group. The mean follow-up time was 30 (range 21-39) months. At the latest follow-up, no patient experienced re-dislocation in either group. Except for the femoral torsion and tibial torsion in the control group, postoperative imaging parameters were significantly reduced to the normal range. KDRO group has a lower patellar tilt angle (P=.043, effect size 0.64). All clinical scores in both groups significantly improved postoperatively. KDRO group has better functional scores than control group except the KOOS daily living activities subscore and the KOOS sports and recreation subscore. More proportions of patients in KDRO group met the minimal clinically important difference (MCID) for most PROs than control group. Eight patients (44%) in the control group complained of postoperative anterior knee pain, compared with 1 patient (6%) in KDRO group (P=.018).

CONCLUSION

KDRO combined with MPFLR was associated with better postoperative outcomes than TTT combined with MPFLR in patients with RPI and a torsion deformity.

Clinical and Radiological Outcomes After Combined ACL and MPFL Reconstruction Versus Isolated ACL Reconstruction for ACL Injury With Patellar Instability

BACKGROUND

An anterior cruciate ligament (ACL) injury accompanied by patellar instability (PI) is a topic that has gained orthopaedic surgeons' attention recently. Untreated PI is reportedly associated with worse clinical outcomes after isolated ACL reconstruction (ACLR) in patients after an ACL injury with PI. Nevertheless, the appropriate surgical approach and its long-term therapeutic effects in these patients remain unclear.

PURPOSE

(1) To compare the clinical and radiological outcomes between isolated ACLR (iACLR) and combined ACLR and medial patellofemoral ligament reconstruction (cAMR) in patients after an ACL injury with PI and (2) to explore the correlations between these 2 procedures and clinical and radiological outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 106 patients diagnosed with an ACL injury accompanied by PI between January 2016 and April 2021 were analyzed in this study. There were 34 patients excluded because of missing postoperative radiological data. Among the remaining 72 patients, 34 patients underwent iACLR, while 38 patients underwent cAMR. Demographic characteristics, intraoperative findings, and patient-reported outcomes (Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity score) were prospectively collected. Patellar alignment parameters and worsening patellofemoral osteoarthritis (PFOA) features (evaluated with the modified Whole-Organ Magnetic Resonance Imaging Score) were analyzed longitudinally on magnetic resonance imaging. The Kujala score was used to evaluate the functional recovery of the patellofemoral joint, and redislocations of the patella were prospectively recorded. Finally, multivariate logistic regression analysis was used to explore the correlations between these 2 procedures and clinical (not achieving the minimal detectable change [MDC] for the Lysholm score) and radiological (worsening PFOA features) outcomes.

RESULTS

The mean follow-up duration was 28.9 ± 6.2 and 27.1 ± 6.8 months for the iACLR and cAMR groups, respectively (P = .231). Significantly higher Lysholm scores (88.3 ± 9.9 vs 82.1 ± 11.1, respectively; P = .016) and subjective International Knee Documentation Committee scores (83.6 ± 11.9 vs 78.3 ± 10.2, respectively; P = .046) were detected in the cAMR group compared with the iACLR group postoperatively. The rates of return to preinjury sports were 20.6% and 44.7% in the iACLR and cAMR groups, respectively (difference, 24.1% [95% CI, 3.3%-45.0%]; P = .030). Moreover, the rates of worsening PFOA features were 44.1% and 18.4% in the iACLR and cAMR groups, respectively (difference, 25.7% [95% CI, 4.9%-46.4%]; P = .018). In addition, significantly higher Kujala scores (87.9 ± 11.3 vs 80.1 ± 12.0, respectively; P = .006), lower redislocation rates (0.0% vs 11.8%, respectively; difference, 11.8% [95% CI, 0.9%-22.6%]; P = .045), and significantly better patellar alignment were detected in the cAMR group compared with the iACLR group postoperatively. Furthermore, multivariate logistic regression analysis determined that iACLR and partial lateral meniscectomy were significantly correlated with not achieving the MDC for the Lysholm score and worsening PFOA features in our study population.

CONCLUSION

In patients after an ACL injury with PI, cAMR yielded better clinical and radiological outcomes compared with iACLR, with better patellar stability and a lower proportion of worsening PFOA features. Furthermore, not achieving the MDC for the Lysholm score and worsening PFOA features were significantly correlated with iACLR and partial lateral meniscectomy. Our study suggests that cAMR may be a more appropriate procedure for patients after an ACL injury with PI, which warrants further high-level clinical evidence.

Surgical treatment of patellar dislocation: A network meta-analysis of randomized control trials and cohort studies

Background

Currently, there are many surgical options for patellar dislocation. The purpose of this study is to perform a network meta-analysis of the randomized controlled trials (RCTs) and cohort studies to determine the better treatment.

Method

We searched the Pubmed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, clinicaltrials.gov and who.int/trialsearch. Clinical outcomes included Kujala score, Lysholm score, International Knee Documentation Committee (IKDC) score, redislocation or recurrent instability. We conducted pairwise meta-analysis and network meta-analysis respectively using the frequentist model to compare the clinical outcomes.

Results

There were 10 RCTs and 2 cohort studies with a total of 774 patients included in our study. In network meta-analysis, double-bundle medial patellofemoral ligament reconstruction (DB-MPFLR) achieved good results on functional scores. According to the surface under the cumulative ranking (SUCRA), DB-MPFLR had the highest probabilities of their protective effects on outcomes of Kujala score (SUCRA 96.5 %), IKDC score (SUCRA 100.0%) and redislocation (SUCRA 67.8%). However, DB-MPFLR (SUCRA 84.6%) comes second to SB-MPFLR (SUCRA 90.4%) in Lyshlom score. It is (SUCRA 70%) also inferior to vastus medialis plasty (VM-plasty) (SUCRA 81.9%) in preventing Recurrent instability. The results of subgroup analysis were similar.

Conclusion

Our study demonstrated that MPFLR showed better functional scores than other surgical options.

The effect of quadriceps anatomical factors on patellar stability: A systematic review

PURPOSE

The aim of this systematic review was to analyse the effect of quadriceps anatomical factors on patellar stability.

METHODS

The protocol for this review was registered on PROSPERO with registration number CRD42022334265. A systematic PRISMA compliant database search was conducted. Electronic databases (MEDLINE, Global Health, MIDIRS, Embase, PsycARTICLES and APA PsycInfo), currently registered studies, conference proceedings and the reference lists of included studies were searched. A narrative synthesis provided a summary of current evidence pertaining to the effect of quadriceps anatomical factors on patellar stability.

RESULTS

A total of 9168 records were screened in the initial search. Of these, 20 articles satisfied the inclusion criteria, assessing 754 knees of 689 patients, and 69 cadaveric knees. Vastus medialis obliquus strength (VMO) affected patellar stability up to 15° of knee flexion, whereas medial retinaculum integrity did so up to 30° of knee flexion. Studies disagreed as to whether this applied to the rest of knee flexion. There is conflicting evidence regarding the effect of VMO elevation, cross-sectional area and angulation on patellar stability. The lateral retinaculum contributed to patellar stability throughout the entirety of knee flexion. Quadriceps angle altered patellar orientation during knee flexion, but not extension.

CONCLUSION

Whilst vastus medialis obliquus strength was found to be a determinant of patellar stability, there is conflicting evidence regarding the effect of VMO morphological parameters on patellar stability. The lateral retinaculum provided stability throughout the entirety of knee flexion, and the medial retinaculum did so up to 30° of flexion.

Double-Tunnel Technique Was Similar to Single-Tunnel Technique in Clinical, Imaging and Functional Outcomes for Medial Patellofemoral Ligament Reconstruction: A Randomized Clinical Trial

PURPOSE

This study aimed to compare the clinical, functional, and imaging outcomes of single-tunnel (ST) and double-tunnel (DT) techniques for medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Ninety-four patients with recurrent patellar instability were randomly divided into 2 groups, receiving either ST or DT MPFL reconstruction. Lateral reticulum release (LRR) and tibial tuberosity (TT) transfer were performed as combined procedures when necessary. Preoperative and postoperative clinical characteristics (symptoms and episodes of redislocation), functional outcomes (Kujala, Lysholm, Tegner, IKDC, and KOOS score), and radiological measurements (congruence angle, patellar tilt angle, lateral patellar angle, and lateral patellar translation) were analyzed.

RESULTS

The analysis included data from 90 patients with 48 patients in the ST group and 42 patients in the DT group. Patients were followed up for a mean period of 37.8 (range: 27-50) months in the ST group and 38.6 (range: 25-53) months in the DT group. Forty-three patients in the ST group and 40 patients in the DT group received combined TT transfer, and all patients underwent LRR. At the latest follow-up, 1 patient in ST group experienced redislocation, while no patient in the DT group sustained clinical failure (P = .347). Imaging measurements decreased significantly to the normal range postoperatively. No significant difference was noted between the postoperative radiological results of the 2 groups. All clinical scores significantly improved postoperatively, and no significant difference was observed between the 2 groups except for the higher Lysholm score (P = .031), KOOS symptoms score (P = .021) and KOOS knee-related quality of life score (P = .043) in the DT group.

CONCLUSION

Both techniques could equally mitigate the patellar lateral translation or redislocation. Our results demonstrate several significant differences in functional outcomes that favored DT MPFL reconstruction but no difference in clinical failure rates and radiological results between ST and DT MPFL reconstruction.

LEVEL OF EVIDENCE

Level I, randomized clinical trial.

Comparison of Clinical and Radiological Results of Lateral Retinacular Release or Lateral Retinacular Lengthening Methods Combined With Medial Retinaculum Plication in Patellofemoral Instability

Introduction

In this study, we aimed to compare the clinical and radiological results of patients who underwent medial retinaculum plication (MRP) combined with lateral retinacular release (LRR) or lateral retinacular lengthening (LRL) with the diagnosis of patellofemoral (PF) instability.

Methods

In our study, we retrospectively analyzed 75 knees of 75 adult patients (43 females and 32 males) who underwent MRP+LRR or MRP+LRL due to PF instability without osseous pathologies. Patients were divided into two groups (MRP+LRR and MRP+LRL) according to the surgical method. The clinical and radiological results of the two groups were compared.

Results

MRP+LRL surgery was performed on 45 knees and MRP+LRR surgery on 30 knees. The mean age was 26.5 (18-43) years. There was no significant difference between the two groups in the change in patellar lateral shift (PLS) (p=0.429) and congruence angle (CA) (p=0.218) values. However, there was a significant difference between the two groups in the change in patellar tilt angle (PTA) (p=0.009) and lateral patellofemoral angle (LPFA) (p<0.001) values. The change in PTA and LPFA values was higher in the MRP+LRL group. There was no significant difference between the two groups in terms of pre-operative and post-operative Lysholm knee scoring scale (p=0.205, p=0.228), Kujala pain scale (p=0.393, p=0.596), and Tegner activity level scale values (p=0.121, p=0.899).

Conclusions

MRP+LRR or MRP+LRL provided successful results for correcting the instability in PF instability without osseous pathologies such as patella alta, tibial tubercle-trochlear groove (TT-TG) dysplasia, trochlea dysplasia, genu valgus, and tibial-femoral torsion. While PTA and LPFA values improved more with the MRP-LRL method, clinical results were similar in both methods.

Polyethylene Suture Augmentation of the Medial Patellofemoral Ligament in Skeletally Immature Patients with Recurrent Patella Dislocation

In skeletally immature patients with recurrent patella dislocation that needs operation, how to increase the medial stability of the patella effectively without disturbance of the epiphysial plate is of concern. Through evaluation of multiple techniques that designed to avoid injury to the epiphysial plate, we found that medial patellofemoral ligament augmentation with high-strength nonabsorbable sutures is feasible and effective. Thus, we would like to describe this technique, whose critical point is the correct location and creation of the 2 femoral tunnels. We consider the introduction of the current technique will provide reasonable choices when operation is needed in this special group of patients.

Closing-wedge distal femoral osteotomy combined with medial patellofemoral ligament reconstruction for recurrent patellar dislocation with genu valgum

BACKGROUND

Medial patellofemoral ligament reconstruction (MPFLR) is a well-established procedure for addressing recurrent patellar dislocation (RPD) in young patients. However, despite being a promising procedure for RPD with genu valgum, there is a scarcity of reports on simultaneous MPFLR and closing-wedge distal femoral osteotomy (CWDFO). The purpose of the present study was to observe and analyse the clinical and imaging findings of CWDFO combined with MPFLR for RPD with genu valgum.

METHODS

From May 2015 to April 2018, 25 patients with RPD and genu valgum were surgically treated in our department. Anteroposterior long-leg, weight-bearing, lower-extremity radiographs, lateral radiographs and computed tomography (CT) scans of the patellofemoral joint were obtained, and the anatomical femorotibial angle (aFTA), mechanical lateral distal femoral angle (mLDFA), weight-bearing line rate (WBLR), patellar height, patellar lateral shift (PLS) and tibial tubercle-trochlear groove (TT-TG) distance were analysed. Validated knee scores, such as the Kujala, Lysholm, visual analogue scale (VAS) scores and Tegner socres, were evaluated preoperatively and 2 years postoperatively.

RESULTS

25 patients, with an average age of 19.8 years (14-27), were evaluated. During the 2-year follow-up period, all patients were able to achieve a better sports level without any problems, with no recurrence of patellar instability. Compared with preoperation, the aFTA, mLDFA, WBLR and PLS showed statistically significant improvement following the procedure (p < 0.001). Meanwhile, no significant differences in the Insall index and TT-TG distance were found. The mean Kujala score, average Lysholm score, VAS score and Tegner socres showed significant postoperative improvement.

CONCLUSIONS

CWDFO combined with MPFLR is a suitable treatment for RPD with genu valgum, and can lead to significant improvement in the clinical and imaging findings of the knee in the short term.

Evaluation of recurrent dislocation of the patella in children with MRI: Goldthwait technique combined with lateral release, and VMO advancement-a retrospective study of 85 knees

PURPOSE

There are certain risk factors responsible for patella instability that should be identified before choosing the most appropriate treatment.

METHODS

We evaluated 83 skeletally immature patients who, after two or more patellar dislocation episodes, underwent surgical treatment to address the condition of patellar instability. Each patient was evaluated for patellar instability risk factors using the Balcarek patellar instability severity score. Evaluation of patellar instability included knee MRI to systematically identify anatomical risk factors. The preoperative and postoperative clinical evaluation included the modified Cincinnati score and the Kujala score. The Roux-Goldthwait technique combined with lateral retinaculum release and the advancement of the vastus medialis oblique (VMO) was performed on all knees.

RESULTS

The mean patient age at the time of surgery was 12.2 ± 1.59 years (range 8-14 years). The average follow-up was 4.72 ± 1.37 (range 3-8) years. Trochlear dysplasia (decreased trochlear depth), the most common anatomical risk factor, was identified in 71 knees (83.5%). The modified Cincinnati score increased from 58.46 ± 8.75 (range 49-76) points to 94.07 ± 2.88 (range 88-98) postoperatively. The mean Kujala scores increased from 58.51 ± 8.94 (range 49-76) points to 93.66 ± 2.65 (range 87-98) postoperatively. The two-tailed P value was less than 0.0001. The patients were followed until their skeletal maturation, without reporting any incidents of patella dislocation, except one.

CONCLUSION

The Roux-Goldthwait technique combined with lateral retinaculum release, and the advancement of VMO, can restore patellar tracking and can decrease the probability of another dislocation. It was an effective treatment in skeletally immature patients who had two or more episodes of patellar dislocation.

LEVEL OF EVIDENCE

IV.

High failure rate 10.8 years after vastus medialis transfer and lateral release (Green's quadricepsplasty) for recurrent dislocation of the patella

PURPOSE

In adolescent patients with recurrent patellar dislocation, the Green's quadricepsplasty stabilizes the patella in a combination of a lateral release, a transfer of the medial head of the quadriceps onto the lateral part of the patella and an imbrication of the medial patellar retinaculum and joint capsule. This study aimed to evaluate the long-term performance, considering re-dislocations and functional outcomes. We hypothesized a high failure rate in the long term.

METHODS

In this single surgeon and single center study 26 knees in 23 patients (mean age 14.2 years; 4-22 years, 18 females) with recurrent patellofemoral dislocation underwent a vastus medialis transfer, medial reefing and lateral release as it was described by Green in 1965 with a mean follow-up 10.8 years (6-24 years). Clinical assessment was carried out with an IKDC-score (international knee documentation committee) and a self-assessment for each knee separately. The radiologic evaluation included measurement of the patella height, the grade of trochlear dysplasia and the sulcus angle.

RESULTS

In 12 of 26 cases (46.2%) the patella did not re-dislocate after vastus medialis transfer and lateral release. In 11 of 26 cases (42.3%), the patients described the function of their knees as normal or nearly normal according to IKDC after the surgical treatment without any re-dislocation. In 14 of 26 cases (53.8%), the patella re-dislocated. 7 of these 14 cases underwent a revision operation. Re-dislocations occurred after a mean interval of 21 months after the index procedure. In only 2 of 26 cases (7.7%) the patients returned to sports.

CONCLUSION

Green's procedure to stabilize patellofemoral instabilities results in a high failure rate on the long-term and low subjective assessments. We do not recommend performing vastus medialis transfer, medial imbrication and lateral release as a standalone technique.

LEVEL OF EVIDENCE

IV.

Surgical management for recurrent patellar dislocations in skeletally immature patients

BACKGROUND

Due to his multifactorial aetiology, treating patellofemoral instability can be a challenge for the orthopaedic surgeon. The incidence of patellofemoral instability shows a peak during adolescence, especially from 11 to 14 years old.

AIM

Several clinical studies focusing on recurrent patellar dislocations in skeletally immature patients have been published, reporting inconsistent or controversial results. Currently, there is a lack of consensus regarding the surgical management of these patients. The purpose of this study is to update current evidence and systematically review indications, treatments, and outcomes of surgical management for recurrent patellar dislocations in skeletally immature patients.

METHODS

A comprehensive review of the literature was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis, the PRISMA Statement. The following electronic databases were accessed in February 2019: PubMed, Scopus, Google Scholar, CINAHL, EMBASE. All the articles treating surgical management for recurrent patellar dislocations in skeletally immature patients were considered for inclusion. For the methodological quality assessment, we referred to the Coleman Methodology Score (CMS). For the statistical analysis, we referred to the unpaired t-test to establish whether the results are statistically significant.

RESULT

The overall CMS resulted in 52.78 points, attesting a satisfactory methodological quality assessment to this systematic review. A total of 21 articles including 623 patients (577 knees) were evaluated. The overall mean age was 13.02 years. The mean follow-up was 46.61 months. The mean Kujala score improved from 58.94 ± 10.38 to 87.07 ± 7.68 points. The Lysholm score reported a pre- and post-operative mean values of 49.54 ± 14.20 and 88.32 ± 8.80, respectively. The mean Tegner Activity Scale scored 4.28 ± 1.22 at baseline, improving to 5.26 ± 0.83 post-operatively. A total of 4.19% of patients incurred into a major complication, while 9.6% sustained a minor one. We observed a total of 89 re-dislocations above 692 treated knees (12%).

CONCLUSION

The main findings of this study are that surgical procedures for skeletally immature patients affected by recurrent patellar dislocations are feasible and effective. Complications and re-dislocations occurred infrequently. It is of fundamental importance to treat precociously these patients in order to reduce the risk of further recurrences, to increase the level of sporting activity and improving the quality of life.

Medial Patellofemoral Ligament Reconstruction: A Comparison of Single-Bundle Transpatellar Tunnel and Double-Anchor Anatomic Techniques for the Treatment of Recurrent Lateral Patellar Dislocation in Adults

PURPOSE

To compare the stability and clinical outcomes of 2 medial patellofemoral ligament reconstruction (MPFLR) techniques for the treatment of recurrent lateral patellar dislocation in adults.

METHODS

Ninety-one patients with recurrent patellar dislocation were randomly divided into 2 groups, undergoing either the traditional single-bundle transpatellar tunnel technique (group A) or the double-anchor anatomic reconstruction technique (group B). Preoperatively and at follow-up, the patellar position and rotation were evaluated by computed tomography with the congruence angle, lateral patellar angle, patellar tilt angle, and lateral patellar translation; the subjective symptoms and functional outcomes were evaluated with Kujala, Lysholm, Tegner, and International Knee Documentation Committee subjective scores. Clinical examinations were also performed, and redislocations or episodes of instability were recorded.

RESULTS

Patients were followed up for a mean period of 41.11 ± 7.40 months (range, 29-62 months). At the final point, no recurrent patellar dislocations occurred, except in 4 patients with instability symptoms in group A; however, no significant difference between the 2 groups was seen (χ² = 2.503, P = .114). The measurement results from computed tomography decreased significantly to the normal range, and no significant difference was found between the 2 groups except for the lesser patellar tilt angle in group B (t = 2.175, P = .030). The clinical examination improved significantly, no patient exhibited a positive apprehension test in either group, and the number of patients with abnormal lateral patellar translation grade and firm end point showed no statistically significant differences between the 2 groups (P > .05). All score systems significantly improved with no significant difference between the 2 groups except for the higher Kujala score (t = -40.635, P = .001) and International Knee Documentation Committee score (t = -33.823, P = .003) in group B.

CONCLUSIONS

Both MPFLR techniques achieved good results in the treatment of patellar dislocation. Compared with the single-bundle transpatellar tunnel technique, the double-anchor anatomic MPFLR technique may be more effective with a more congruous patellofemoral joint and better knee function.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Modified Roux-Goldthwait Procedure for Management of Patellar Dislocation in Skeletally Immature Patients with Down Syndrome

BACKGROUND

Patellar instability is a common problem in Down syndrome patients since their childhood. Several treatment have been proposed, but relapses are frequent and not all surgeries are suitable for growing patients. The aim of the present study is to evaluate the clinical and radiographic outcomes of a modified Roux-Goldthwait technique, for the management of patellar instability in children with Down syndrome at minimum 5-year followup.

MATERIALS AND METHODS

19 patients (23 knees) affected by Down syndrome surgically treated for patellar dislocation, between 2000 and 2012 were included in this study. The mean age of patients was 9.5 years (range 3.7 - 15 years) and had a Dugdale Grade III, IV, and V patellar dislocation. Trochlear groove dysplasia was present in 15 patients. Each patient was clinically evaluated considering relapse rate, pre- and postoperative range of motion (ROM), Kujala score, and modified Lysholm score. Radiographic examination was performed on standard X-ray considering patellar height, trochlear angle, and patellofemoral congruence angle.

RESULTS

The mean followup was 134 months (range 62-206 months). No case of relapse of dislocation was registered with an improved ROM (significant for knee extension, P < 0.05). The Kujala score showed significant improvement from a mean preoperative value of 39 ± 6.3 to a mean postoperative value of 92.7 ± 3.4 (P < 0.05) at final followup such as the modified Lysholm score (from mean preoperative 55.6 ± 6.3 to mean postoperative of 94.2 ± 2.6). Radiographs performed at latest followup showed a tendency to normalization of all the parameters considered, with a restored patellofemoral congruence and trochlear groove shape and without signs of osteoarthritis.

CONCLUSION

The present study showed that the Roux-Goldthwait procedure is a valid surgical option for the treatment of patellar dislocation in children with Down syndrome.

Patellofemoral joint alignment is a major risk factor for recurrent patellar dislocation in children and adolescents: a systematic review

Importance

The complex interplay of risk factors that predispose individuals to recurrent patellar dislocation is poorly understood, especially in paediatric patients who exhibit the most severe forms.

Objective

The primary aim of this study was to systematically review the current literature to characterise the lower limb alignment, patellofemoral morphology and soft tissue restraints of the patellofemoral joint (PFJ) through medical imaging measurements in paediatric recurrent patellar dislocators and age-matched control participants. The secondary aims were to synthesise the data to stratify the factors that influence PFJ stability and provide recommendations on the assessment and reporting of PFJ parameters in this patient population.

Evidence review

A systematic search was performed using CINAHL, the Cochrane Library, EMBASE, PubMed and Web of Science databases until June 2017. Two authors independently searched for studies that included typical children and adolescents who experienced patellar dislocation and also had direct measures of structural and dynamic risk factors. The methodological quality of the included studies was assessed through a customised version of the Downs and Black checklist. Weighted averages and SDs of measures that have been reported in more than one study were computed. A fixed-effects model was used to estimate the mean differences with 95% CIs regarding the association of recurrent patellar dislocation with patella alta, tibial tuberosity to trochlear groove (TT-TG) distance and bony sulcus angle.

Findings

20 of 718 articles met the inclusion criteria. Thirty-one risk factors were found; however, only 10 of these measurements had been assessed in multiple articles and only four had both dislocator and control population results. With respect to controls, patients with recurrent patellar dislocations had higher TT-TG distance (p<0.01) and higher bony sulcus angle (p<0.01).

Conclusions and relevance

Based on the current scientific literature, increased TT-TG distances and bony sulcus angles predispose children and adolescents to recurrent patellar dislocation. Besides these measurements, studies reporting on recurrent patellar dislocation in children and adolescents should also include characterisation of lower limb alignment in coronal and axial planes and assessment of generalised ligamentous laxity.

Level of evidence

Systematic review of prognostic studies, Levels II–IV.

Medial patella-femoral ligament reconstruction using the anterior half of the peroneus longus tendon as a combined procedure for recurrent patellar instability

Background

Medial patella-femoral ligament reconstruction (MPFLR) using hamstring tendon is the main procedure for recurrent patellar instability. The anterior half of the peroneus longus tendon (AHPLT) has been proven to be a useful alternate to the hamstring tendon in knee ligament reconstruction. The purpose of this study was to evaluate the clinical outcome of MPFLR using the new graft.

Methods

Forty-five patients with recurrent patellar instability received MPFLR using the AHPLT. Tibial tubercle transfer and lateral release were also performed. Follow-ups were performed at 12 months and 24 months postoperatively, and computed tomography was performed immediately following the operation and at follow-up. The passive patella glide test was performed prior to surgery, during the operation, and at each follow-up point. Knee function was evaluated preoperatively and postoperatively using the International Knee Documentation Committee, Lysholm, Kujala, and Tegner rating scales.

Results

Forty patients were followed for 2 years and received complete serial computed tomography examinations and functional evaluations. The correction of the static patellar position remained through the follow-ups. Functional evaluations at 2 years revealed statistical significant improvement over preoperative status, with International Knee Documentation Committee subjective score, Lysholm score, Kujala score, and Tegner score.

Conclusion

AHPLT is a promising alternative graft for MPFLR, together with lateral release and tibial tubercle transfer, satisfactory static patellar position, and functional outcomes have been achieved in the treatment of recurrent patellar dislocation in adults.

Level of evidence

Level IV, case series.

Medial capsule reefing in patellar instability

PURPOSE

The efficacy of medial capsule reefing in the treatment of patellar instability is well documented. Aim of the present study was to prospectively evaluate the outcomes of an all-arthroscopic medial capsule reefing technique in young patients with painful patella syndrome and potential patellar instability.

METHODS

Thirty patients with painful patellar syndrome and potential patellar instability having undergone a minimum of 6 months of intensive rehabilitation were enrolled in the present study. All subjects were evaluated with physical examination, clinical and functional outcomes and complete imaging study.

RESULTS

All patients were reviewed at an intermediate follow-up of 72 months. Average Kujala score improved from 72.9±15.0 to 88.4±7.6 (p<0.0001), average Larsen score from 15.0±2.5 to 17.2±2.2 (p<0.002), average Lysholm from 63.8±16.7 to 87.9±11.7 (p<0.0001) and average Fulkerson score from 69.5±21.5 to 90.8±9.8 (p<0.0001). No intraoperative or postoperative complications were recorded. Ninety per cent of patients were very satisfied or satisfied with their functional result. Twenty-eight patients were reviewed at the final follow-up, 120 months after surgery. Average Kujala was 87.7±8.8 (p<0.0001), average Larsen was 16.8±2.7 (p<0.01), average Lysholm was 87.6±14.3 (p<0.0001), and average Fulkerson was 87.2±13.9 (p<0.0001). Almost 86% of patients were very satisfied or satisfied with their result. However, slight deterioration of the outcomes over time was observed.

CONCLUSION

At the final follow-up, the outcomes of all-arthroscopic technique were significantly improved from preoperative values; however, they were slightly inferior at the 72 months follow-up. This slight deterioration of the outcomes may be the consequence of the reduction in physical activities.

LEVEL OF EVIDENCE

Case series, Level IV.

Medial retinaculum reefing for the treatment for patellar instability

PURPOSE

Medial structures repair is a well-established approach in the treatment for patellar instability. However, the literature is confusing concerning the indications for surgery, the different surgical techniques and outcomes. The goal of this systematic review was to clarify the indications for medial structures repair and to analyse the results of both arthroscopic and open techniques.

METHODS

A comprehensive literature review was performed using the keywords 'patellar instability', 'medial capsule reefing' and 'medial capsule plication' with no limit regarding the year of publication. All the selected articles in Anglo-Saxon language were evaluated with the Coleman methodology score.

RESULTS

Seventeen full-text articles were evaluated. Initial cohort included 617 patients. About 569 patients were reviewed at an average FU of 54.6 months (range 2-165 months) after medial structures repair. Average age at the time of surgery was 21.2 years (range 9-65 years). The indications for surgery included both patellar subluxation and dislocation (acute or chronic). Average Kujala score increased from 55 to 84 at the last FU, and in the same way average Lysholm score increased from 41.2 to 80.5, whereas average Tegner score increased from 3 to 5.3 and IKDC score from 47.8 to 75.1. Re-dislocation rate among the series was 6.1%. Average Coleman methodology score was 61.6 (range 17-92).

CONCLUSION

From this review, it emerges that medial capsule reefing is a reliable option in the treatment for patellar instability. It can be proposed with good expectations, since the outcomes are positive and stable even at longer FU and complications rates are low. Re-dislocation rate is variable and can occur in up to one-third of patients. However, most of the available studies are case series, and comparison of the series is hard since they widely differ in inclusion criteria and indications, surgical technique and additional procedures, and outcome measures.

Treating patella instability in skeletally immature patients

PURPOSE

The purpose of this study was to comprehensively and systematically review the current evidence for orthopaedic treatment of immature and adolescent patients with acute and chronic patellar instability.

METHODS

We searched the online databases PubMed, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews for relevant publications on patellar instability. All dates and languages were included.

RESULTS

Twenty articles reporting on a total of 456 knees in 425 patients (131 male patients, 294 female patients) followed-up for 56.7 ± 42.2 months on average were included in the analysis. Two studies focused specifically on conservative versus surgical treatment in acute dislocations and reported no difference in outcomes after 7 and 14 years, even in the face of slight trochlear dysplasia. For recurrent instability, we found consistent beneficial effects from surgical stabilization on clinical scores, postoperative stability, and radiographic assessment. There is no evidence for growth disturbance with surgical patellar stabilization in immature patients.

CONCLUSIONS

The current best evidence does not support the superiority of surgical intervention over conservative treatment in an acute patellar dislocation. However, anatomic variations and their effect on healing should be considered and included in decision making. In recurrent patellar instability in pediatric and adolescent patients with normal or restored knee anatomy, reconstruction of the medial patellofemoral ligament (MPFL) is the most effective treatment option and can be done safely, together with extensor realignment as needed.

LEVEL OF EVIDENCE

Level IV, systematic review of mixed-level studies.

The operative management of patella malalignment

Management of patellofemoral joint pathology is challenging as a result of the unique and complex organization of static forces and dynamic factors contributing to its functional capacity. Anterior knee pain is a common musculoskeletal complaint seen daily in the practices of primary care physicians, rheumatologists, and orthopedic surgeons. The key to successful treatment lies not only in the correct diagnosis of a chondral defect, but more importantly, in the accurate identification of associated pathomechanical factors. Appreciating the pathoanatomic basis of the disease and addressing imbalances and anatomical abnormalities should guide treatment.Despite the complexity of the interplay of various components it is essential to attempt to describe patellar malalignement as a clinical entity in order to proceed with appropriate surgical management and successful outcomes. The goals of patellofemoral re- alignment surgery should be to create both a stable environment for optimal extensor mechanism performance and an appropriate load transmission for optimal cartilage wear and joint loading. In the context of this article we will review the operative management of patellofemoral malalignment; the indications for surgery, the different techniques available and the evidence regarding their effectiveness.A large number of procedures have been employed and they have all undergone various modifications over the course of the years. The majority of publications are retrospective series in poorly defined population groups. There are significant methodological inconsistencies and as a result there is lack of strong evidence base for the majority of these procedures.

Medial patellofemoral ligament reconstruction using semitendinosus tendons: polyester suture augmentation versus nonaugmentation

BACKGROUND

The comparative clinical outcome of medial patellofemoral ligament reconstruction (MPFLR) using semitendinosus tendons with and without polyester suture augmentation for recurrent patellar instability is unknown.

HYPOTHESIS

Medial patellofemoral ligament reconstruction with polyester suture augmentation will yield better results than MPFLR without augmentation for recurrent patellar instability in adults.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

One hundred patients with recurrent patellar instability receiving MPFLR using semitendinosus tendons were randomly divided into 2 groups either with or without polyester suture augmentation. Tibial tubercle transfer was performed in most cases. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patellar glide test was performed before surgery, immediately after MPFLR during the operation, and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee, Lysholm, and Kujala rating scales. Redislocation or multiple episodes of patellar instability were considered failures.

RESULTS

Forty-two patients in the augmentation group and 43 patients in the nonaugmentation group were followed for 5 years and received complete serial CT examinations and functional evaluations. The correction of the static patellar position deteriorated over time in the nonaugmentation group but not in the augmentation group. The results of the passive patellar glide test indicated stable patellae in all patients immediately after MPFLR and more stable patellae in the augmentation group at each follow-up point. Functional evaluations at 2 and 5 years revealed statistically significant superior results in the augmentation group. Finally, no patient in the augmentation group and 2 (4.7%) in the nonaugmentation group experienced episodes of redislocation, and 1 patient (2.4%) in the augmentation group and 8 (18.6%) in the nonaugmentation group experienced multiple episodes of patellar instability, resulting in failure rates of 2.4% and 23.3% in the augmentation group and nonaugmentation group, respectively (P = .004).

CONCLUSION

Medial patellofemoral ligament reconstruction with polyester suture augmentation results in better static patellar position, dynamic stability, and functional outcome than without augmentation in the treatment of recurrent patellar dislocation in adults.

The role of medial retinaculum plication versus medial patellofemoral ligament reconstruction in combined procedures for recurrent patellar instability in adults

BACKGROUND

The comparative clinical outcome of medial retinaculum plication (MRP) versus medial patellofemoral ligament reconstruction (MPFLR) for recurrent patellar instability in adults is unknown.

HYPOTHESIS

Arthroscopic MRP can yield similar results to MPFLR for recurrent patellar instability in adults.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

One hundred patients with recurrent patellar instability were randomly divided into 2 groups receiving either arthroscopic MRP or MPFLR. Lateral release and anteromedial or distal tibial tubercle transfers were also performed as indicated. Follow-ups were performed at 12, 24, and 60 months postoperatively, and computed tomography (CT) was performed immediately after the operation and at follow-up. The passive patella glide test was performed before surgery and at each follow-up point. The degree of knee function was evaluated preoperatively and at 2 and 5 years postoperatively using the International Knee Documentation Committee (IKDC), Lysholm, and Kujala rating scales. Survival analysis was performed, and redislocation or multiple episodes of patellar instability were considered as indicating failure.

RESULTS

Forty-three patients in the MRP group and 45 patients in the MPFLR group were followed for 5 years and received complete evaluations. The correction of the static patellar position deteriorated over time in both groups, but significantly better results were observed for the MPFLR group. The results of the passive patella glide test indicated more stable patellae in the MPFLR group at each follow-up point. Functional evaluations at 2 and 5 years (final Lysholm score, 69.3 ± 6.9 vs 86.9 ± 6.1; Kujala score, 73.8 ± 5.5 vs 87.4 ± 5.7) revealed statistically significant superior results in the MPFLR group. Finally, 4 patients (9.3%) in the MRP group and 1 (2.2%) in the MPFLR group experienced episodes of redislocation, and 7 patients (16.3%) in the MRP group and 3 (6.7%) in the MPFLR group experienced multiple episodes of patellar instability (P = .037). Kaplan-Meier survival analysis and a log-rank test indicated better results and a significantly higher survival rate (P = .006) in the MPFLR group.

CONCLUSION

MPFLR results in better static patellar position and functional outcome than MRP in the treatment of recurrent patellar dislocation in adults.