Isolated Medial Patellofemoral Ligament Reconstruction Research Articles

Patella alta is reduced following MPFL reconstruction but has no effect on quality-of-life outcomes in patients with patellofemoral instability.

The primary purpose of this study was to determine if isolated medial patellofemoral ligament (MPFL) reconstruction for lateral patellofemoral instability altered the patellar height ratio. Secondary purposes were to use disease-specific quality-of-life scores to determine if MPFL reconstruction is as successful in patients with patella alta, compared to those without; and whether the change in the patellar height ratio after MPFL reconstruction is influenced by demographic and clinical factors. Demographic and clinical data were collected pre-operatively on 283 patients with recurrent patellofemoral instability. Pre-operative and 6-month post-operative true-lateral radiographs were assessed to determine the patellar height ratio using the Caton-Deschamps index. A Caton-Deschamps index ≥ 1.2 was defined as patella alta. Paired t tests evaluated the effect of MPFL reconstruction on the Caton-Deschamps index. Using a two-sample t test, pre- and 24-month post-operative Banff Patellofemoral Instability Instrument (BPII) scores were assessed for differences in clinical outcomes between patients with and without patella alta. Pearson (for continuous variables) and Spearman rank correlations (for binary/ordinal variables) were calculated to determine the relationship between the patellar height ratio, demographic and pathoanatomic risk factors, and pre- and post-operative BPII scores. Pre- and post-operative true-lateral radiographs were admissible for 229/283 patients (81%) following isolated MPFL reconstruction. A statistically significant difference in the Caton-Deschamps index was evident from pre- to post-operative for the entire cohort (p < 0.001). The mean decrease in ratio was 0.03, and the effect size was 0.27, classified as small. Pre-operatively 52/229 patients (22.7%) demonstrated a Caton-Deschamps index ≥ 1.2, mean = 1.27 (SD = 0.08); post-operatively 21/229 patients (9.2%) demonstrated patella alta, mean = 1.18, (SD = 0.10), p < 0.001 (two-tailed). The mean decrease in the Caton-Deschamps index for patients with pre-operative patella alta was 0.10; the effect size was 0.82, classified as large. Pearson r correlation of patella alta to the pre- and post-operative BPII scores demonstrated no statistically significant relationship. This study has demonstrated that treatment of lateral patellofemoral instability with an isolated MPFL reconstruction results in a statistically significant decrease in patellar height ratio, with the effect size being greatest in patients with higher pre-operative Caton-Deschamps indices. In patients that presented with patella alta, normalization of the patellar height ratio occurred in 31/52 (59.6%) of the cases. Pre-operative patella alta was not associated with a statistically significant difference in disease-specific BPII outcome scores at any time point. Given these findings, the utility and results of tibial tubercle distalization in patients with patella alta should be a focus of further research. Level of evidence IV.

FEMORAL TUNNEL FIXATION FOR MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION IN THE GROWING PATIENT IS SAFE FOR FUTURE GROWTH

Background:Medial patellofemoral ligament (MPFL) reconstruction has been shown to be a successful treatment for patients with recurrent patellar instability and is increasingly used to treat skeletally immature patients.Purpose:The purpose of this study is to compare radiographic parameters prior to and following an MPFL reconstruction with femoral tunnel fixation in the skeletally immature patient to investigate potential effects on the physis and future growth.Methods:Skeletally immature patients undergoing isolated MPFL reconstruction were retrospectively reviewed. Fixation of proximal MPFL was performed as a femoral socket using Schottle’s point with the entry approximately 5 mm distal to the physis (Figure 1). Patients with open growth plates and 1-year post-operative standing alignments were included. Radiographic measures of patellar tilt, patellar height, patellar subluxation, and trochlear dysplasia were compared pre-operatively and post-operatively on the operative limb. Pre- and post-operative coronal alignment and limb length measurements were compared between the operative and non-operative limbs.Results:Nineteen skeletally immature patients with an average age of 11.6 years (range 5-15) underwent isolated MPFL reconstruction. The average follow-up time was 24 months. No significant differences were found between the change in femur (0.49 mm, p=0.526) or total limb length (1.08 mm, p=0.241) when comparing the operative to the non-operative limb, with an average of 47 mm of growth in the operative limb seen during the time period. There was no significant difference in the change in LDFA between operative and non-operative limb as well as symmetric changes noted in the mechanical axis. The change in patellar tilt on the operative limb was found to be significant (12.78°, p=0.030), and the change in patellar height by Caton-Deschamps approached significance (0.08mm, p= 0.077). No significant difference was found with trochlear dysplasia measures.Conclusion:The present study suggests MPFL reconstruction with femoral tunnel fixation is safe and does not result in growth disturbance in skeletally immature patients.Figure 1.Fluoroscopic images of the femoral placement of the bone tunnel for the medial patellofemoral ligament reconstruction in a 13 year old male utilizing Schottle point and remaining distal to the physis. (A) Lateral view of the knee (B) Notch view of the knee in order to confirm position of the guide pin distal to the physis posteriorly.

Medial patellofemoral ligament reconstruction with allograft versus autograft tissue results in similar recurrent dislocation risk and patient-reported outcomes

To determine the rate of recurrent dislocation and patellar instability following medial patellofemoral ligament (MPFL) reconstruction with allograft or autograft tissue and compare patient-reported outcomes for patients undergoing allograft and autograft MPFL reconstruction. One hundred and fifteen MPFL reconstructions (78 allograft, 37 autograft) without concurrent bony procedures performed between 2008 and 2014 by four sports medicine fellowship-trained orthopedic surgeons at our center were identified. Patient demographics and surgical data were identified by chart review. Chart review and patient interviews were undertaken to identify recurrent patellar dislocations and as recurrent subjective patellofemoral instability. Recurrent dislocation and subjective instability risk were compared between the allograft and autograft groups. Eighty-seven patients (76%) with complete baseline data and minimum 1-year follow-up were contacted at a mean of 4.1years following isolated MPFL reconstruction, including 57 patient with allograft reconstructions and 30 with autograft reconstructions. No significant differences in patient sex, age at reconstruction, body mass index, or time to follow-up were noted between groups. Recurrent dislocation occurred in 2 patients in the allograft group (3.5%) and 1 patient in the autograft group (3.3%), (n.s.). Recurrent subjective instability occurred in 17 patients in the allograft group (28.9%) and 11 patients in the autograft group (36.7%), (n.s.). No significant differences in patient-reported outcomes were noted between groups. The use of either allograft or autograft tissue for MPFL reconstruction results in low (< 3%) risk of recurrent patellar dislocation. Risk of recurrent subjective instability is higher but is similar for both graft types. Surgeons can utilize either graft choice at their discretion without anticipating a significant impact of graft choice on patient outcomes. III.

Medial Patellofemoral Ligament Isometry in the Setting of Patella Alta

To investigate alterations in technique for medial patellofemoral ligament (MPFL) reconstruction in the setting of patella alta and describe the effect of these alterations on MPFL anatomometry. Ten cadaveric knees were used. Four candidate femoral attachment sites of MPFL were tested. The attachment sites were Schottle's point (SP), 5 mm distal to SP, 5 mm proximal to SP, and 10 mm proximal to SP. A suture anchor was placed at the upper 40% of the medial border of the patella with the emanating suture used to simulate the reconstructed ligament. MPFL maximum length change was calculated through a range of motion between 0° and 110°. Recordings at all 4 candidate femoral attachments sites were repeated after a flat tibial tubercle osteotomy and transfer to achieve alta as measured by the Caton-Deschamps Index (CDI) of 1.3, 1.4, and 1.5. The 10 specimens had an average CDI of 0.99, range 0.87 to 1.16. In the native tibial tubercle condition, SP was more isometric through 20° to 70° range of motion, or anatomometric, than any other candidate femoral attachment location. With patella alta with a CDI of 1.3 and 1.4, attachment site 5 mm proximal to SP exhibited more anatomometry than SP. With patella alta with a CDI of 1.5, attachment site 10 mm proximal to SP exhibited more anatomometry than SP. Increased patella alta significantly alters MPFL anatomometry. With increasing degrees of patella alta, more proximal candidate femoral attachment sites demonstrate decreased change in length compared with SP. None of the varied femoral attachments produced anatomometry over the entirety of the flexion range from 20° to 70°, suggesting that in cases of significant patella alta, proximalization the femoral attachment site of MPFL reconstruction may be necessary to achieve an anatomometric MPFL reconstruction. A standardized, isolated MPFL reconstruction may be prone to failure in the setting of patella alta, given the anisometry demonstrated. Alternative femoral attachment sites for MPFL reconstruction should be considered in these patients.

Patellar instability

Lateral patellar dislocation (PD) has multifactorial origin. Its treatment will depend on the physical demands of the patient, triggering event and injury mechanism of PD, number of dislocation episodes, patellofemoral joint morphology, and concomitant injuries. After primary PD, despite the risk of recurrence being 33-77%, first treatment option is mostly conservative, except if an osteochondral fragment needs to be refixed or removed. This practice has been questioned lately by the Patella Instability Severity Score that determines the risk for recurrent PD in function of age, bilaterality, and anatomical risk factors. Risk behavior in relation to sports activity seems to be an additional risk factor. The treatment of recurrent PD is surgical with only low recurrent rate (2-4%). Medial patellofemoral ligament (MPFL) reconstruction is the most widely used technique. The ideal candidates are subjects with painless intervals between PD and without major trochlear dysplasia (TD) or patella alta. However, postoperative pain and loss of flexion might be observed if the graft is overtensioned or its fixation point malpositioned. Trochleoplasty is the only technique that aims at improving containment with the risk to increase peak forces due to incongruence. Due to the demanding technique its superiority over isolated MPFL reconstruction has been described only in grotesque TD and PD in higher knee flexion (&gt;60°). Tibial tubercle osteotomy can be distalized in case of patella alta or medialized in case of lateralized tibial tubercle. Indication should be considered carefully, since patellar tracking will be influenced almost throughout the full range of motion and might therefore induce discomfort or pain.

Medial patellofemoral ligament reconstruction technique

Backgroud Recurrent patellar dislocation is a challenging medical problem for both the patient and the surgeon because of its multifactorial etiology.The medial patellofemoral ligament (MPFL) extends between the superomedial border of the patella and the anterior aspect of the medial femoral epicondyle in layer 2 of the medial soft tissue structures In the last decade, there have been many techniques for reconstruction of the MPFL. All techniques rely on supplying tendinous reconstruct from the medial border of the patella to the adductor tubercle, using different tendonsThe aim of this study was to describe the technique of reconstruction of MPFL and evaluation of the results using transverse holes in the patella and femoral interference screw. Patients and methods From January 2013 to April 2016, 20 cases underwent isolated MPFL reconstruction, after institutional ethics approval and informed consent was obtained from every patient. Out of the operated 20 cases, there were 12 females and eight males, with an average age of 24 years. Average age at the first dislocation episode was 21±2 years. Mean follow-up is about 18.3 months (range: 9–28), a mean of 4.8 dislocations per patient (range: 3–16 times). All were caused by either trauma or physical activity (14 trauma, six physical activity). Results All cases regained full range of motion; the apprehension sign dropped from 90% preoperative in 18 cases to 15% postoperative (only three cases). The glide test dropped from 100to 0% in follow-up. Mean Lysholm score improved significantly from 58%±3 to 93%±4. Conclusion MPFL reconstruction for treatment of recurrent patellar dislocation with a gracilis tendon autograft, using transverse holes in the patella and a screw for femoral fixation, showed good results at short-term follow-up

Medial Patellofemoral Ligament Reconstruction with and without Tibial Tubercle Osteotomy

Objectives: The medial patellofemoral ligament (MPFL) is the primary soft-tissue restraint against lateral patellar displacement. Surgery to address MPFL incompetence is the current gold standard for recurrent patellofemoral instability. The role of tibial tubercle osteotomy (TTO) as an adjunct to MPFL reconstruction remains controversial. Our purpose was to evaluate a cohort of patella instability patients undergoing surgical soft tissue stabilization with or without concomitant TTO. Our hypothesis was that there would be no difference between cohorts in baseline values, subjective outcome scores at final follow-up, or complication profile. Methods: Following IRB approval, retrospective review of prospectively collected data identified a consecutive cohort of patients undergoing soft tissue stabilization for recurrent patella instability, with or without concomitant TTO. Indications for TTO were at the surgeon’s discretion, including elevated TT-TG, Caton-Deschamps ratio, and/or unloading chondral lesion(s). Surgery was performed by a single sports fellowship trained surgeon. Pre-surgical and post-surgical patient reported outcomes were collected including KOOS domains, PROMIS (global health, mental health, physical function, pain interference), IKDC, SANE, and Marx scores. Complications requiring re-operation (infection, stiffness, recurrent instability) were recorded. Results were analyzed statistically. Results: The cohort was comprised of 87 patients (95 knees), with 25 males (28.7%) and 62 females (71.3%). The MPFL-TTO cohort had 32 patients (38 knees) and the MPFL-Iso had 55 patients (57 knees). The average age of the MPFL-TTO cohort was 28.3 (range 19.5-44.6) and the average age of the MPFL-Iso group was 29.8 (18.7-55.3). There was no significant difference in pre-operation outcome scores between groups (p&gt;.05). Significant improvements were seen for all KOOS domains in both patient cohorts with no significant differences detected between groups. SANE, IKDC, and PROMIS scores improved significantly with no differences detected between groups. Marx activity score at 6 months post-operatively was significantly different between the groups favoring the isolate MPFL reconstruction cohort. (MPFL-TTO 0.79 +/- 2.15 vs. 4.61 +/- 5.44 in the MPFL-Iso group (p=0.01)). In terms of complications, 4 knees in the MPFL-TTO group required further surgery (2 for stiffness, 1 for infection, and 1 for fracture) and 6 knees in the MPFL-Iso cohort required surgery (4 for stiffness, 1 for infection, and 1 for recurrent instability). Neither the overall complication rate of 4 vs. 6 (p=1) nor the recurrent instability rate of 0 vs. 1 (p=0.41) was significant. Conclusion: In a cohort of patients undergoing MPFL reconstruction, the addition of an appropriately indicated TTO appears to be both safe and effective. Both MPFL-TTO and MPFL-Iso groups demonstrated significant improvement in the majority of subjective outcome scores without major difference between groups. Marx activity scores were higher for the isolated MPFL reconstruction cohort at relatively short term follow-up. The surgical complication profile was similar between groups. Further work is needed to clearly define the role of TTO as an adjunct procedure to MPFL reconstruction.

Quality and Variability of Online Available Physical Therapy Protocols From Academic Orthopaedic Surgery Programs for Medial Patellofemoral Ligament Reconstruction.

Background:Unlike the literature on anterior cruciate ligament reconstruction, studies on medial patellofemoral ligament (MPFL) reconstruction lack evidence-based guidelines regarding postoperative rehabilitation. An effective postoperative protocol may contribute greatly to a successful outcome following MPFL reconstruction, yet the quality and variability of these published protocols remain unknown.Purpose:To assess the quality and variability of MPFL rehabilitation protocols publicly available on the internet and associated with US academic orthopaedic programs.Study Design:Systematic review.Methods:All available isolated MPFL reconstruction rehabilitation protocols from US academic orthopaedic programs participating in the Electronic Residency Application Service were collected and included in this review. These protocols were evaluated for inclusion of various rehabilitation components, the timing of suggested initiation of these activities, and whether the protocol used evaluation-based guidelines.Results:A total of 27 protocols were included. Of these, 25 (93%) recommended immediate postoperative bracing. Time to initiation of full weightbearing ranged from 2 to 8 weeks. The most common strengthening exercises endorsed were quadriceps sets (89%), straight-legged raise (85%), and leg press (81%). The most common proprioception exercises endorsed were balance board (41%), single-legged balance (41%), and TheraBand control (33%). The median time suggested to return to play was 17 weeks. No functional test appeared in the majority of the protocols. Of the 27 protocols, 20 (74%) used evaluation-based guidelines.Conclusion:There is substantial variability in content and timing across rehabilitation protocols following MPFL reconstruction. This lack of clear guidelines can cause confusion among patients, therapists, and surgeons, leading to suboptimal patient outcomes and making it difficult to compare outcomes across the literature.

Isolated Medial Patellofemoral Ligament Reconstruction Can Be an Effective Procedure in Patellofemoral Instability with Risk Factors.

Patellofemoral instability is a severe problem in young and active patients. This pathology is influenced by ligamentous, bony, and neuromuscular parameters. The reconstruction of the medial patellofemoral ligament (MPFL) evolved to a primary procedure, but combined procedures were more frequently performed in the past years. However, additional operative procedures are associated with increased morbidity and no absolute indication can be identified in the literature. This study is intended to clarify whether addressing only ligamentous influence factors (MPFL) in chronic patellofemoral instability is sufficient to produce good clinical outcomes, or whether other risk factors influence the results negatively and should also be treated at some point. In 52 patients with chronic patellofemoral instability patellar height according to Caton-Deschamps, trochlear dysplasia according to Dejour, the leg axis, the femoral antetorsion, tibial tubercle (TT)-trochlear groove, and TT-posterior cruciate ligament distance were evaluated. All patients were treated with isolated MPFL reconstruction. After a minimum follow-up period of 24 months (24-36 months), the clinical outcome results were calculated using the scoring system according to Lysholm and Tegner. Correlation between clinical outcome scores and anatomic risk factors were calculated. The analysis was performed using a standard statistical software package (JMP version 12, SAS Institute, Cary, NC). The average postoperative Lysholm score increased significantly from 57.23 ± 19.9 to 85.9 ± 17.2 points (p < 0.0001) after isolated MPFL reconstruction. Moreover, the Tegner and Lysholm scores significantly improved both in patients without and with different risk factors postoperative. There were no significant differences in the outcome sores between the groups. Even the degree of trochlear dysplasia (types I-III) did not influence the results. Finally, there was no significant correlation found between all collected risk factors and the postoperative outcome scores. Isolated MPFL reconstruction can be an effective procedure in patients with patellofemoral instability and mild to moderate risk factors.

Clinical Outcomes and Predictive Factors for Failure With Isolated MPFL Reconstruction for Recurrent Patellar Instability: A Series of 211 Reconstructions With a Minimum Follow-up of 3 Years

Background: Reconstruction of the medial patellofemoral ligament (MPFL) is widely acknowledged as an integral part of the current therapeutic armamentarium for recurrent patellar instability. The procedure is often performed with concomitant bony procedures, such as distalization of the tibial tuberosity or trochleoplasty in the case of patella alta or high-grade trochlear dysplasia, respectively. At the present time, few studies have evaluated the clinical effectiveness of MPFL reconstruction as an isolated intervention. Purpose: To report the clinical outcomes of isolated MPFL reconstruction in cases of patellar instability and to identify predictive factors for failure. Study Design: Case series; Level of evidence, 4. Methods: A retrospective analysis of prospectively collected data was performed, including all patients who had undergone isolated MPFL reconstruction between January 2008 and January 2014. Preoperative assessment included the Kujala score, assessment of patellar tracking (“J-sign”), and radiographic features, such as trochlear dysplasia according to Dejour classification, patellar height with the Caton-Deschamps index (CDI), tibial tubercle–trochlear groove distance, and patellar tilt. The Kujala score was assessed postoperatively. Failure was defined by a postoperative patellar dislocation or surgical revision for recurrent patellar instability. Results: A total of 239 MPFL reconstructions were included; 28 patients (11.7%) were uncontactable and considered lost to follow-up. Thus, 211 reconstructions were analyzed with a mean follow-up of 5.8 years (range, 3-9.3 years). The mean age at surgery was 20.6 years (range, 12-48 years), and 55% of patients were male. Twenty-seven percent of patients had a preoperative positive J-sign, and 93% of patients had trochlear dysplasia (A, 47%; B, 25%; C, 15%; D, 6%). The mean CDI was 1.2 (range, 1.0-1.7); mean tibial tubercle–trochlear groove distance, 15 mm (range, 5-30 mm); and mean patellar tilt, 23° (range, 9°-47°). The mean Kujala score improved from 56.1 preoperatively to 88.8 (P < .001). Ten failures were reported that required surgical revision for recurrent patellar instability (4.7%). Uni- and multivariate analyses highlighted 2 preoperative risk factors for failure: patella alta (CDI ≥1.3; odds ratio, 4.9; P = .02) and preoperative positive J-sign (odds ratio, 3.9; P = .04). Conclusion: In cases of recurrent patellar instability, isolated MPFL reconstruction would appear to be a safe and efficient surgical procedure with a low failure rate. Preoperative failure risk factors identified in this study were patella alta with a CDI ≥1.3 and a preoperative positive J-sign.

Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Regardless of Tibial Tubercle–Trochlear Groove Distance and Patellar Height: Outcomes at 1 and 2 Years

Background: It is unclear which patients with recurrent patellar instability require a bony procedure in addition to medial patellofemoral ligament (MPFL) reconstruction. Purpose: To report 1- and 2-year outcomes of patients after isolated MPFL reconstruction performed for patellar instability regardless of patellar height, tibial tubercle–trochlear groove (TT-TG) distance, or trochlear dysplasia. Study Design: Case series; Level of evidence, 4. Methods: All patients with recurrent patellar instability and without significant unloadable chondral defects (Outerbridge grade IV), cartilage defects (especially inferior/lateral patella), previous failed surgery, or pain >50% as their chief complaint were prospectively enrolled beginning March 2014. All patients underwent primary, unilateral, isolated MPFL reconstruction regardless of concomitant bony pathology for treatment of recurrent patellar instability. Information on recurrent subjective instability, dislocations, ability to return to sport (RTS), and outcome scores was recorded at 1 and 2 years. TT-TG distance, patellar height (with the Caton-Deschamps index), and trochlear depth were measured. Results: Ninety patients (77% female; mean ± SD age, 19.4 ± 5.6 years) underwent MPFL reconstruction between March 2014 and August 2017: 72 (80%) reached 1-year follow-up, and 47 (52.2%) reached 2-year follow-up (mean follow-up, 2.2 years). Mean TT-TG distance was 14.7 ± 5.4 mm (range, –2.2 to 26.8 mm); mean patellar height, 1.2 ± 0.11 mm (range, 0.89-1.45 mm); and mean trochlear depth, 1.8 ± 1.4 mm (range, 0.05-6.85 mm). Ninety-six percent of patients at 1 year and 100% at 2 years had no self-reported patellofemoral instability; 1 patient experienced a redislocation at 3.5 years. RTS rates at 1 and 2 years were 90% and 88%, respectively. Mean time to RTS was 8.8 months. All patients had clinically and statistically significant improvement in mean Knee injury and Osteoarthritis Outcome Score–Quality of Life (32.7 to 72.0, P < .001), mean International Knee Documentation Committee subjective form (51.4 to 82.6, P < .001), and mean Kujala score (62.2 to 89.5, P < .001). No difference existed between 1- and 2-year outcome scores (all P > .05). Conclusion: At early follow-up of 1 and 2 years, isolated MPFL reconstruction is an effective treatment for patellar instability and provides significant improvements in outcome scores with a low redislocation/instability rate regardless of bony pathologies, including TT-TG distance, Caton-Deschamps index, and trochlear dysplasia. Future data from this cohort will be used to assess long-term outcomes.

A 2-year follow-up of isolated Medial Patellofemoral Ligament Reconstruction by using soft suture anchor and adjustable cortical fixation system

PurposeNumerous surgical techniques and fixation methods have been described in medial patellofemoral ligament (MPFL) reconstruction such as choice of graft, graft fixation method of patella/femur and initial tension. We describe short term clinical results of MPFL reconstruction by using soft suture anchor and adjustable cortical fixation system. MethodsTwenty-four patients who underwent isolated MPFL reconstruction by using soft suture anchor and adjustable cortical fixation system were included in this study. All patients were followed up for at least 2 years, and pre-operative and 2 years post-operative Kujala score, IKDC score and Knee Injury and Osteoarthritis Outcome Score were used to assess clinical outcome. Radiographic evaluation included the Q angle, congruence angle and patellar tilt angle. Pre- and post-operative changes were evaluated by Mann–Whitney U test. ResultsThere were no complications including re-dislocation, patella fracture, infection, and joint contracture. The apprehension test was positive in 4.2% post-operatively. A statistically significant improvement in clinical scores and radiographic evaluation were evident after surgery. ConclusionsIsolated MPFL Reconstruction using soft suture anchor and adjustable cortical fixation system led good restoration of patellar stability and significant improvement of knee function in short-term results. This surgical technique can reduce complications such as patella fractures, and can be done safely. Clinical relevanceThis technique may be a treatment option with little associated complications in the treatment for patellar instability. Level of EvidenceCase series, Level IV.

Lateral retinacular release is not recommended in association to MPFL reconstruction in recurrent patellar dislocation

Reconstruction of the medial patellofemoral ligament (MPFL) has become the gold standard for the treatment of the recurrent patellar dislocation (RPD). Lateral retinacular release can be performed in association with MPFL reconstruction, but the effect on outcomes is not clear. To evaluate the effect of lateral release on outcomes following MPFL reconstruction is the aim of this study. It is hypothesized that isolated MPFL reconstruction was not inferior to MPFL reconstruction and lateral retinacular release in terms of IKDC subjective score and patellar tilt (PT). Patients between ages 18 and 45 scheduled to undergo MPFL reconstruction without an associated bony procedure (tibial tubercle osteotomy or trochleoplasty) were randomized to isolated MPFL reconstruction or MPFL reconstruction (no LRR group) and arthroscopic LRR (LRR group). Evaluation criteria were subjective IKDC score as the primary outcome and PT evaluated with a CT-scan. PT was evaluated with the quadriceps relaxed (PTQR) and contracted (PTQC). Of 43 patients included in the trial, 7 were lost of follow-up, 3 were not able to complete evaluation because of medical reasons, and 33 patients were evaluated with a minimum of 12 months and a median follow-up of 24 (12-60)months. The average subjective IKDC score was at 86 ± 20 (29-94) in the LRR group and 82 ± 15 (39-95) in the no LRR group (p = 0.45). The PTQR was at 22° ± 7° (13-37) in the LRR group and 21 ± 10 (4-37) in the no LRR group (n.s.). The PTQC was at 27° ± 9° (12-40) in the LRR group and 25 ± 12 (5-45) in the no LRR group (n.s.). No complications were noted in either group. No significant differences were found in subjective IKDC score or patellar tilt based on the addition of an arthroscopic LRR to an MPFL reconstruction in patients with RPD not undergoing associated bony procedures. There is no indication to a systematic lateral retinacular release in association with MPFL reconstruction in the treatment of RPD. II.

Single- and double-bundle medial patellofemoral ligament reconstruction procedures result in similar recurrent dislocation rates and improvements in knee function: a systematic review.

To evaluate medial patellofemoral ligament (MPFL) reconstruction using hamstring tendon autografts using single-bundle (SB) and double-bundle (DB) techniques, and compare the clinical outcomes including the Kujala score, postoperative apprehension, recurrent subluxation or dislocation, and complications. The PubMed, Embase, and Cochrane Library databases were searched for relevant literature using the terms ''medial patellofemoral ligament'' and ''MPFL''. The pooled mean values of improvement in the Kujala score were calculated by random effects meta-analysis. Unweighted estimates for the rates of postoperative apprehension, recurrent subluxation or dislocation, and complications were determined by dividing the total number of occurrences by the total number of knees. Thirty-one articles were included, involving 1063 patients (1116 knees). Two hundred and forty-four patients (254 knees) underwent SB reconstruction, while 819 patients (862 knees) underwent DB reconstruction. The pooled mean values of Kujala score improvement were similar in the SB group (30.1; 95% CI 26.6-33.6) and DB group (30.7; 95% CI 27.7-33.7). The SB group had a significantly greater rate of postoperative apprehension (7.9%) than the DB group (4.1%; P = 0.014). There were no significant differences between the two groups in the rates of recurrent subluxation or dislocation (1.2 and 1.6%) and complications (10.6 and 7.7%). With variability in patient populations and surgical techniques, the DB procedure for isolated MPFL reconstruction demonstrates similar outcomes to the SB technique regarding improvement of knee function, recurrent subluxation or dislocation, and complications. The SB technique may have a greater risk of postoperative apprehension, whereas the DB technique may cause more stiffness. IV.

Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Regardless of the Tibial Tubercle Trochlear Groove Distance: Outcomes at 1 and 2 Years

Background:Several surgical options exist for treatment of recurrent patellar instability. The treatments can be divided into ligamentous and bony procedures. It is currently unclear which patients require a bony procedure in addition to a soft tissue reconstruction.Purpose:To report the one and two-year outcomes of patients following medial patellofemoral ligament (MPFL) reconstruction performed in isolation regardless of the patellar height, tibial tubercle trochlear groove distance (TT-TG) or trochlear dysplasia.Hypothesis::Patients will have <5% re-dislocation rate and significant improvements in patient reported outcome measures (PROMs) following isolated MPFL reconstruction.Methods:All patients with recurrent patellar instability and without significant unloadable chondral defects, failed previous surgery or pain greater than or equal to 50% as their chief complaint, were prospectively enrolled beginning March of 2014. All patients underwent a primary, unilateral, isolated MPFL reconstruction regardless of concomitant bony pathology for treatment of recurrent patellar instability. Patients were followed at standard intervals. PROMs were collected at one year and two year follow up visits. Information on recurrent subjective instability, dislocations, and ability to return to sport (RTS) was recorded. TT-TG and patellar height (using the Caton-Deschamps index) were measured on magnetic resonance images.Results:Overall, 90 patients (77% female; average age 19.4 +/- 5.6 years) underwent a MPFL reconstruction from March 2014 to August 2017; 63 (70%) of whom reached one year follow up, and 35 of these patients (39%) reached 2-year follow-up. No patient experienced a redislocation; 96% of patients at one year and 100% of patients at two years had no subjective patellofemoral instability. RTS rates at one and two years were 59% and 75% respectively. No patient experienced a complication at one year. All patients had a clinically and statistically significant improvement from baseline to 1-year follow-up in the following PROMs: Knee injury and Osteoarthritis Outcome Score Quality of Life (KOOS QOL) (32.7 to 72.0; p<0.001), International Knee Documentation Committee (IKDC) (51.4 to 82.6; p<0.001) Kujala (62.2 to 89.5; p<0.001), and all general health PROM. No clinically and statistically significant change was seen between 1- and 2-year follow-ups in all outcome scores (all p>0.05). A non-statistically significant increase was seen in sporting activity of the Pediatric Functional Activity Brief Scale (Pedi-FABS) (13.9 to 16.7 p=0.292) at 2 years. Average patient satisfaction was 9.3 of 10 (10 being most satisfied) at 1- and 2-year follow-up. Average TT-TG was 15.1 +/- 4.0. Average patellar height was 1.25 +/- 0.17.Conclusion:Isolated MPFL reconstruction is an effective treatment for patellar instability and provides significant improvements in PROMs with a low redislocation/instability rate at early 1 and 2 year follow up, regardless of bony pathologies including TT-TG, Caton-Deschamps Index and trochlear dysplasia. The goal of this ongoing prospective study is to follow these patients out for 5 to 10 years to assess what radiologic and physical examination factors predict failure of isolated MPFL reconstruction.

Examination under Anesthesia in Patients with Recurrent Patellar Dislocation: Prognostic Study.

Surgical management of patellar instability is a matter of wide debate. While some authors believe that isolated medial patellofemoral ligament (MPFL) reconstruction is sufficient, others advocate procedures to treat the underlying pathology, namely, patella alta and trochlear dysplasia. Radiological studies have been traditionally used as a determinant of these pathologies and to determine the need for an additional procedure. The value of examination under anesthesia (EUA) in formulating a treatment plan remains unknown. Our aim is to assess the prognostic value of EUA in assessing patients presenting for surgical treatment of recurrent patellar dislocations. We retrospectively reviewed the outcome after surgical treatment of 23 patients who had undergone isolated MPFL reconstruction for recurrent patella dislocation by a single surgeon in our tertiary center. All data were completed at the time of index surgery. Primary outcome was recurrent instability requiring revision surgery. The mean age of the 23 patients undergoing MPFL reconstruction was 17.4 years of age. The median trochlea tuberosity-trochlear groove (TT-TG) distance was 15 mm with a median Caton-Deschamps ratio of 1.3. Of the 23 patients who underwent MPFL reconstruction, 9 failed (39%). Median time to failure was 10.5 months. All patients who failed MPFL reconstruction had a dislocating patella on EUA at >30 degrees of flexion. Radiological assessment of the knee to assess its morphology is essential for preoperative surgical planning for patients with recurrent patellar instability. Cutoff values to determine the need for surgical procedures require a consistent method of imaging and are prone to flaws in measurement. However, we demonstrated that EUA provides valuable additional information toward an appropriate surgical approach.Based on our small cohort, we suggest that patients in whom patella remains dislocated past 30 degrees of knee flexion on EUA are unlikely to benefit from isolated MPFL reconstruction.

Clinical Outcomes After Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Among Patients With Trochlear Dysplasia

Background: Medial patellofemoral ligament (MPFL) reconstruction has become one of the most common and widely used procedures to regain stability among patients with recurrent lateral patellar dislocation. While recent studies demonstrated low recurrence rates, improved patient-reported outcome measures, and a high rate of return to sports, limited literature explored its effectiveness as an isolated intervention in the context of trochlear dysplasia. Purpose: To determine the efficacy of isolated MPFL reconstruction in treating patellar instability in the setting of trochlear dysplasia. Study Design: Case series; Level of evidence, 4. Methods: This was a retrospective review of consecutive patients who underwent uni- or bilateral medial patellofemoral ligament reconstruction for patellofemoral instability with a minimum 2-year follow-up. No osteotomies were included. Pre- and postoperative assessment included ligamentous laxity, patellar crepitus, tilt, translation, apprehension, and radiographic features, including tibial tubercle-trochlear groove (TT-TG) distance, Dejour classification, and Caton-Deschamps index. Results: A total of 121 MPFL reconstructions were included. Mean age at surgery was 23.8 years, and 4.4 dislocation events occurred before surgery. Mean follow-up was 44 months; 76% of patients were female. Mean preoperative TT-TG ratio was 13.5, and mean Caton-Deschamps ratio was 1.2; 92% of patients had Dejour B, C, or D trochlear dysplasia. Kujala score improved from 55.0 preoperatively to 90.0 (P < .001). Almost all patients (94.5%) were able to return to sports at 1 year, with 74% returning to the same or higher level of play. Only 3 patients reported a postoperative dislocation or subluxation event. Discussion: For patients without significantly elevated TT-TG distances or significant patella alta, isolated MPFL reconstruction provides a safe and effective treatment for patellofemoral instability, despite the presence of trochlear dysplasia. Most patients are able to return to sports by 1 year postoperatively at the same or higher level of play.

Anisometry of Medial Patellofemoral Ligament Reconstruction in the Setting of Increased Tibial Tubercle–Trochlear Groove Distance and Patella Alta

To assess the impact elevated tibial tubercle-trochlear groove (TT-TG) distance and patella height, as measured by the Caton-Deschamps Index (CDI), have on the isometry of a reconstructed medial patellofemoral ligament (MPFL). Nine fresh-frozen cadaveric knees were placed on a custom testing fixture, with a fixed femur and a mobile tibia. A suture fixed to the MPFL origin on the patella and free to move at the Schöttle point on the femur represented a reconstructed MPFL. A local coordinate system was established, and retroreflective markers attached to the suture quantified MPFL length changes by use of a 3-dimensional motion capture system. The tubercle was transferred to create TT-TG distances of 20mm and 25mm and CDIs of 1.2 and 1.4 (patella alta). Recordings of the MPFL suture length change as the knee was brought through a range of motion were made using all combinations of tubercle anatomy in a randomized order for each specimen. A generalized estimating equation modeling technique was used to analyze and control for the clustered nature of the data. Knees with native tibial tubercle anatomy showed MPFL isometry through 20° to 70° range of motion. Tibial tubercle lateralization (increased TT-TG distance) significantly altered MPFL isometry with a TT-TG distance of 20mm(P < .0001). Patella alta significantly altered MPFL isometry with a CDI of 1.2 (P= .0182). The interaction of tibial tubercle lateralization combined with patella alta significantly increased the amount of anisometry seen in the reconstructed MPFL (P < .001). Increased tibial tubercle lateralization and patella alta produce anisometry in an MPFL reconstruction using currently recommended landmarks, leading to potentially increased graft tension and potential failure. Tibial tubercle transfer should be considered when performing an MPFL reconstruction for recurrent patellofemoral instability in the setting of significant patella alta and an elevated TT-TG distance-especially when both are present-because an isolated MPFL reconstruction will be prone to failure given the anisometry shown in this study.

Allograft Versus Autograft for Medial Patellofemoral Ligament Reconstruction

The use of either allograft or autograft tissue for MPFL reconstruction results in a very low (<3%) risk of repeat dislocation. Patellofemoral instability with recurrent patellar dislocations is a debilitating condition that frequently affects a young, active patient population. Isolated medial patellofemoral ligament (MPFL) reconstruction has emerged as an effective treatment of recurrent patellar dislocations that occur in the absence significant patellofemoral malalignment or osseous abnormalities. Both allografts and autografts have been successful used for MPFL reconstruction. We hypothesize that MPFL reconstruction with allograft or autograft tissue yields similar low rates of recurrent dislocation and subjective patellar instability. Chart review identified 117 MPFL reconstructions (80 allograft and 37 autograft) without concurrent bony procedures (such as tibial tubercle osteotomy) performed between 2008 and 2014 by four sports medicine fellowship trained orthopedic surgeons at our center. Patient demographics (age and sex) and surgical data (graft type) were identified by chart review. Chart review and patient interviews were undertaken to identify recurrent patellar dislocations as well as recurrent subjective patellofemoral instability. Recurrent dislocation and subjective instability risk were compared between the allograft and autograft groups. 53 patients (45%) with complete baseline data and minimum 1 year follow-up were contacted at a mean of 4.5 years following isolated MPFL reconstruction, including 37 patient with allograft reconstructions and 16 with autograft reconstructions. No significant differences in patient sex, age at reconstruction, body mass index, or time to follow-up were noted between groups. Recurrent dislocation occurred in 1 patient in the allograft group (2.7%) and 0 patients in the autograft group (0%), (p = 0.51). Recurrent subjective instability occurred in 9 patients in the allograft group (24.3%) and 5 patients in the autograft group (31.2%), (p = 0.74). The use of either allograft or autograft tissue for MPFL reconstruction results in a very low (<3%) risk of repeat dislocation. Recurrent subjective instability occurs more frequently (1/4 to 1/3 of patients) at a similar rate for both graft types.

Double-bundle anatomical medial patellofemoral ligament reconstruction with lateral retinaculum plasty can lead to good outcomes in patients with patellar dislocation.

To evaluate the clinical outcomes of double-bundle anatomical medial patellofemoral ligament (MPFL) reconstruction combined with lateral retinaculum plasty versus isolated MPFL reconstruction for patellar dislocation. From 2011 to 2013, 64 patients underwent either double-bundle anatomical MPFL reconstruction combined with lateral retinaculum plasty (Group A, 32 patients), or isolated MPFL reconstruction (Group B, 32 patients). Clinical evaluations were performed 2years post-operatively and included determination of the number of patients with patellar redislocation, the patellar tilt angle, lateral patellar shift, subjective symptoms, and functional outcomes as evaluated with the Kujala score and Lysholm score. No dislocation or subluxation occurred during the 25-month follow-up. Radiographically, the patellar tilt angle was 6.0°±1.7° in Group A and 6.7°±2.0° in Group B, without a significant difference (n. s). The lateral patellar shift was 8.0±2.6mm in Group A and 8.5±2.4mm in Group B (n. s). The mean Kujala score was 91.8±3.7 in Group A and 91.5±3.6 in Group B post-operatively (n. s), and the mean Lysholm score was 92.5±3.8 and 90.8±4.9, respectively (n. s). Double-bundle anatomical MPFL reconstruction with lateral retinaculum plasty is a promising procedure that provides a new option for patellar dislocation. III.