Lateral Dislocation Research Articles

Incidence of primary patellar dislocation in Colombia

Introduction and objectivesPrimary acute patellar dislocations (PAPD) account for 3% of all traumatic knee lesions, and several studies have estimated the general incidence of patellar dislocation to be between 2 and 77.4 per 100,000 person-years. Few studies have evaluated the incidence of primary lateral patellar dislocation in Latin America. The aim of the study was to evaluate the incidence of patellar dislocation in patients from a reference center in the Colombian southwest, report trends in the incidence of dislocation, and describe the rate of surgical treatment. Materials and methodsWe performed an observational, analytical, cross-sectional study including all patients older than 9 years old with primary lateral patellar dislocation (PLPD), between January 2011 and June 2018, in a tertiary care center in Latin America. ResultsIn our population, the incidence of primary lateral patellar dislocation (PLPD) was 32.38 per 100,000 person-years. The age group between 14 and 18 years old had the highest incidence (187.74 per 100.000). In the 10 to 13-year-old group, females had a significantly higher incidence (179.05 vs 59.85 /100,000, p-value<0.001). ConclusionsWith an incidence of 32.38 per 100,000 person- years, primary patellar dislocation is a frequent orthopaedic injury in our population. The peak incidence by age group was in adolescents between 14 to 18 years old.

Knee Injury-Baseball

HISTORY: A 19yo male college baseball pitcher presented for acute onset left medial knee pain after attempting to carry a couch, at which time he twisted the knee into a valgus position and felt a painful pop. He had mild difficulty with weight bearing and swelling. He questioned whether he may have dislocated the kneecap with spontaneous reduction. He denied associated bruising, instability, hip or back pain. He denied prior knee injury. He did report mild chronic groin pain during pitching which was unchanged. PHYSICAL EXAMINATION: There was mild effusion about the left knee, with tenderness at the medial joint line and near the proximal origin of the MCL. There was pain with valgus stress, without clear laxity. Varus stress was non-provocative. Anterior and posterior drawer test were limited secondary to guarding. Lachman's test was equivocal. McMurray's test was positive for pain. Patellar apprehension was positive. Patellar grind was negative. Straight leg test was negative. Distal neurovascular exam was grossly intact. DIFFERENTIAL DIAGNOSIS: Lateral patellar dislocation/subluxation. ACL or MCL sprain/tear. Traumatic medial meniscus tear. Osteochondral lesion of the medial femoral condyle. Muscle or tendon sprain/tear. TEST AND RESULTS: Left knee X-ray was negative for fracture and showed normal alignment. Left knee MRI revealed nonspecific edema throughout the deep soft tissues of the posterior distal thigh and knee, most pronounced along the posteromedial aspect of the distal femoral metaphysis near the insertion of the adductor magnus tendon. Findings were suggestive of acute on chronic partial tearing/avulsion injury of the distal adductor magnus with an adjacent focus of mineralization consistent with underlying calcific tendinosis. The cruciate and collateral ligaments were intact. There were no findings suggestive of transient lateral patellar dislocation. FINAL WORKING DIAGNOSIS: Calcific tendinosis of the adductor magnus tendon, with superimposed traumatic avulsion injury/partial tearing TREATMENT AND OUTCOMES: The patient was allowed to weight bear as tolerated but was instructed to abstain from lower body exercise for 4 weeks. NSAIDs were used for pain relief as needed. He was referred to PT at 4 weeks with a focus on pitching mechanics.

Lateral Femoral Condyle CRATER sign of BRIK an Ancillary Sign of Lateral Patellar Dislocation

Introduction Acute lateral patellar dislocation is a common knee injury pattern. However, coincidental osseous defect may be present in normal knees. Purpose Evaluate the characteristics of osseous bone defect and describe a new ancillary sign associated with lateral patellar dislocation. Materials and Methods Magnetic resonance imaging (MRI) of 50 consecutive patients referred following a traumatic lateral patellar dislocation of the knee joint and 50 patients with knee pain without MR features of patellar dislocation were obtained for evaluation over a 7-year period. They were analyzed for location of bony defects in the periarticular region. Results Of the 50 patients who underwent MRI following a reduced traumatic lateral patellar dislocation, 3 patients had an osseous "crater" of more than 2 mm in depth on the non-articular surface of the lateral femoral condyle. None of control group of patients had an osseous defect measuring more than 2 mm in depth. Conclusion This associated finding of an osseous "crater" of more than 2 mm on the non-articular surface of the lateral femoral condyle following traumatic lateral patellar dislocation is a rare occurrence. We highlight this as an ancillary sign of lateral patellar dislocation necessitating careful evaluation (Crater sign of Bhamidipaty Rajesh Iyengar Kartik [BRIK]). The presence of lateral femoral condyle "CRATER" sign of BRIK on MRI undertaken for other reasons in the knee, in the absence of osseous edema may suggest a past episode of severe, reduced patellar dislocation.

Diagnostic value of various criteria for deep lobe involvement in radiologic studies with parotid mass: a systematic review and meta-analysis.

To assess the diagnostic utility of various radiologic criteria such as the lateral margin or dislocation of the retromandibular vein (RMV), Utrecht line, facial nerve line, Conn's arc, lines passing from the lateral margin of the masseter muscle to the facial nerve trunk or RMV, minimum distance from the fascia to the tumor (MDFT), and direct tracing of the intraparotid facial nerve (DT) for differentiating a parotid deep lobe tumor from a superficial lobe tumor. Twenty-one studies with 2225 participants from PubMed, Embase, Web of Science, Cochrane Library, SCOPUS, and Google Scholar up to March 2022 were analyzed. Sensitivity, specificity, and negative and positive predictive values of the methods were extracted. The diagnostic odds ratio (DOR) of radiologic criteria compared to surgical findings was 18.9109. The area under the summary receiver operating characteristic curve was 0.879. The sensitivity and specificity were 0.6663 and 0.9190. MDFT (DOR 61.2917) and DT (DOR 91.9883) showed superior results as diagnostic landmarks. For tumors crossing the anatomical criteria line, strict way (any tumor crossing the line) could help differentiate a deep lobe tumor more accurately than conventional way (> 50% of the tumor volume located medial to the line). Various radiologic criteria, especially MDFT and DT, showed good diagnostic accuracy for differentiating a parotid deep lobe tumor.

Laterally Based External Fixation for Pott's Fractures.

In this article, we describe the construction and appropriate use of a lateral-based fixator for ankle fractures. This lateral-based frame is useful for treating Pott's fractures. With lateral ankle dislocations, the lateral frame places the hindfoot in alignment with the leg. Soft tissue trauma has been recognized as an early limiting factor in patients with ankle fractures, in addition to the need for obtaining and maintaining anatomic position. A kickstand is added for heel and medial soft tissue offloading. The lateral frame is a quick and reproducible technique with satisfactory results.Level of Evidence: Level V: Surgical Technique.

Anatomical Components Associated With Increased Tibial Tuberosity-Trochlear Groove Distance.

Background:Increased tibial tuberosity–trochlear groove (TT-TG) distance is an important indicator of medial tibial tubercle transfer in the surgical management of lateral patellar dislocation (LPD). Changes to TT-TG distance are determined by a combination of several anatomical factors.Purpose:To (1) determine the anatomical components related to increased TT-TG distance and (2) quantify the contribution of each to identify the most prominent component.Study Design:Case-control study; Level of evidence, 3.Methods:Included were 80 patients with recurrent LPD and 80 age- and body mass index–matched controls. The 2 groups were compared in TT-TG distance and its related anatomical components: tibial tubercle lateralization (TTL), trochlear groove medialization, femoral anteversion, tibiofemoral rotation (TFR), tibial torsion, and mechanical axis deviation (MAD). The Pearson correlation coefficient (r) was calculated to evaluate the association between increased TT-TG distance and its anatomical parameters, and factors that met the inclusion criteria of P < .05 and r ≥ 0.30 were analyzed via stepwise multivariable linear regression analysis to predict TT-TG distance.Results:The LPD and control groups differed significantly in TT-TG distance, TTL, TFR, and MAD (P < .001 for all). Increased TT-TG distance was significantly positively correlated with TTL (r = 0.376; P < .001), femoral anteversion (r = 0.166; P = .036), TFR (r = 0.574; P < .001), and MAD (r = 0.415; P < .001), and it was signficantly negatively correlated with trochlear groove medialization (r = −0.178; P = .024). The stepwise multivariable analysis revealed that higher TTL, excessive knee external rotation, and excessive knee valgus were statistically significant predictors of greater TT-TG distance (P < .001 for all). The standardized estimates that were used for evaluating the predictive values were larger for TFR compared with those for TTL and MAD.Conclusion:TTL, TFR, and MAD were the main independent anatomical components associated with increased TT-TG distance, with the most prominent component being TFR. The association of TT-TG distance to each component analyzed in our study may help guide surgical planning.

New anatomical landmark for rotational assessment of total knee arthroplasty

One of the most controversial topics in total knee arthroplasty is rotation of the femoral component. The current gold-standard in total knee arthroplasty consists in positioning the femoral component in 3 degrees of external rotation to the epicondylar axis, having as reference the tangent to the posterior condyles. Achieving the correct rotation of the femoral components is one of the main goals during total knee arthroplasty. Multiple complications can result from internal femoral rotation, such as lateral patellar tilt, patellar subluxation or dislocation, mobilization with movement on pain, and low survival rates of the femoral components. Postoperative rotational assessment of protective components can only be performed correctly using computed tomography. The known evaluation methods are related to anteversion of the femoral neck, femoral trans-epicondylar line, insertion of the posterior cruciate ligament from the tibia and tibial tuberosity. The purpose of this study was to evaluate the rotation of the prosthetic components in the group of patients with the methods validated by studies and to find alternatives to evaluate the rotation of the femoral component. Thirty-four patients diagnosted with gonarthrosis, proposed for total knee arthroplasty, were included in the study. This is a prospective cohort study in which applied statistics consisted of analyzing data using frequency and percentage for qualitative and mean variables and standard deviation for quantitative variables

Paper 53: Comparing Graft Choice in Medial Patellofemoral Ligament Reconstruction

Objectives:Disruption of the medial patellofemoral ligament (MPFL) may lead to recurrent lateral patellar dislocation and patellofemoral chondral injury. Optimal graft choice for MPFL reconstruction in the surgical treatment of patellar instability is unknown. While autograft remains readily available, easily harvested, and of lower cost, allograft is a viable alternative and portends several benefits over autograft. Autograft may provide superior strength or lower re-tear rate, but allograft has been shown to have similar outcomes with less donor site morbidity in some series. Overall, there is a paucity of research comparing autograft vs allograft in MPFL reconstruction. Prior studies have been limited by small sample sizes, incomplete data, or heterogeneous patient population. The objectives of this study were to compare outcomes scores, return to activity and revision rates between allograft and autograft in MPFL reconstruction. The authors hypothesized that there would be no significant difference in outcomes between those who received an allograft and those who received an autograft in MPFL reconstruction.Methods:Patients who underwent isolated MPFL reconstruction with allograft or autograft at a single institution between 2013-2020 were retrospectively reviewed. Patients with a follow-up of less than 2 years were excluded, along with those who underwent concomitant tibial tubercle osteotomy or trochleoplasty. Patients were contacted to complete functional assessments including the Single Assessment Numeric Evaluation (SANE), Visual Analog Scale for pain (VAS), and International Knee Documentation Committee (IKDC) scores. Patient demographics and complications were also reviewed. Outcomes were compared between those that underwent allograft and autograft MPFL reconstructionResults:Out of the fourty-six patients that were retrospectively reviewed, thirty-one (67.4%) patients underwent allograft reconstruction, while fifteen (32.6%) patients underwent autograft reconstruction. There were no differences between the two groups in age at surgery (25.2 years old in allograft vs 26.3 years old in autograft group, P=0.726), sex ratio (19F/12M in allograft and 9F/6M in autograft, P=1.000), or BMI (27.0 in allograft and 24.8 in autograft, P=0.179).There was a mean follow up duration of 4.57 years in the allograft group and 4.83 years in the autograft group (P=0.672), with an overall response rate of 70.2%. There were no differences between the two groups when assessing subjective pain using SANE (66.7 in allograft vs 74.5 in autograft, P=0.334) or VAS score (35.7 in allograft vs 22.9 in autograft, P=0.110). Further there were no differences in patient outcomes as assessed by IKDC score (68.3 in allograft vs 76.2 in autograft, P=0.247). Patients who received an allograft returned to activity at an average of 5.9 months, while patients who received an autograft returned to activity at an average of 5.2 months (P=0.416). One patient in the allograft group required revision surgery (P=0.246).Conclusions:Both allograft and autograft remain viable options in MPFL reconstruction. There were no significant differences in failure rates, PROs, pain, or time to return to play between allograft and autograft MPFL reconstruction in this series.

Paper 54: MPFL Repair has a Higher Failure Rate at Long-term Follow-up compared to MPFL Reconstruction for Recurrent Patellar Instability

Objectives:The medial patellofemoral ligament (MPFL) is the primary soft tissue restraint to lateral patellar translation and is often disrupted with a lateral patellar dislocation. Surgical management for recurrent patellar instability focuses on restoring MPFL function with repair or reconstruction techniques. Recent studies have favored reconstruction over repair, but no long-term, comparative studies are available in the literature.Methods:A total of 55 patients (58 knees) with recurrent lateral instability were treated between 2005 and 2012 with either MPFL repair or MPFL reconstruction. Exclusion criteria included prior or concomitant tibial tubercle osteotomy or trochleoplasty, and follow-up less than 8 years. Pre- and post-operative demographic, surgical, imaging and clinical data were recorded for each patient.Results:MPFL repair was performed on 26 patients (29 knees; 14 females, 15 males) at a mean age of 19.1 years. MPFL reconstruction was performed on 29 patients (29 knees; 18 females, 11 males) at a mean age of 18.2 years. Mean follow-up was 12.0 years (range 8.3-18.9). The reconstruction group had a significantly lower rate of recurrent dislocation compared to the repair group (14% vs 41%, p=0.019) at final follow up. There were no differences in the number of pre-operative dislocations (greater than or less than 3), degree of patellar facet chondromalacia, TT-TG distance, or Tegner scores. The reconstruction group had significantly more time from injury to surgery compared to the repair group (median, 1,460 days vs 627 days, p =0.007). There were no differences in post-operative Tegner, Lysholm or Kujala scores at final follow-up. Additionally, there were no differences in return to play rates (repair 80.8% vs reconstruction 75.0%, p=0.610) or reoperation rates (repair 20.7% vs reconstruction 13.8%, p=0.487).Conclusions:Repair of the MPFL leads to nearly 3-fold higher rate of recurrent patellar dislocation (41% vs. 14%) at long term follow-up compared to MPFL reconstruction. However, MPFL repair and reconstruction provide similar clinical results, return to play rates and reoperation rates.

Poster 226: Autograft versus Allograft for Medial Patellofemoral Ligament Reconstruction: A Systematic Review

Objectives:Patients with recurrent lateral patellar dislocations are often treated with reconstruction of the medial patellofemoral ligament (MPFL). The purpose of this study was to perform a systematic review to evaluate clinical outcomes and the risk of recurrent patellar dislocation following medial patellofemoral ligament reconstruction (MPFLR) with autograft versus allograft.Methods:A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify studies comparing outcomes of MPFLR with autograft versus allograft. The search phrase used was: medial patellofemoral ligament reconstruction autograft allograft. The inclusion criteria were full-text studies that directly compared clinical outcomes and/or risk of recurrent patellar instability events between patients undergoing MPFLR with autograft versus allograft. A quality assessment was performed using the Modified Coleman Methodology Score (MCMS). Risk of bias was performed using the ROBINS-I and the Cochrane Collaboration’s risk of bias tools.Results:Seven studies (one level II, three level III, three level IV) were identified that met inclusion criteria, including a total of 150 patients who underwent MPFLR with autograft and 193 with allograft (Figure 1, Table 1). All studies showed a moderate risk of bias due to confounding, and five studies showed a moderate risk of bias for using non-blinded but identical postoperative protocols. All six studies showed serious risk of bias for using physicians not blinded to the treatment group (Figure 2). One study found a significantly higher failure rate among autograft patients, and another study found a trend toward a significantly higher failure rate among autograft patients (Table 2). One study demonstrated no significant difference between tibial tubercle-trochlear groove distance (measured on magnetic resonance imaging) in failed versus successful grafts. One study found that patellar tilt angle improved significantly from preoperatively to postoperatively (p<0.001), but there was no difference between the groups. Kujala scores significantly improved for both autograft and allograft patients across studies. Two studies found significant differences in postoperative Kujala scores between the two groups, one of which found better scores in allograft patients (p=0.0032) and another in which scores were better in autograft patients (p=0.02).Conclusions:This is the first systematic review limited to comparative studies comparing autograft versus allograft for MPFL reconstruction. Patients undergoing MPFLR with either autograft or allograft can expect to experience improvement in clinical outcomes. Graft failure was more frequently observed in autograft patients. Subjective outcomes improved to a similar degree in both groups. Allograft may be a better option for MPFLR due to lower failure rate.Figure 1.Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram.Figure 2.ROBINS-I risk of biasTable 1.Study characteristicsTable 2.Failure rates.

Mental and physical health-related quality of life in patients with recurrent patellar dislocations—a generic and disease-specific quality of life questionnaire assessment

PurposeThere is a paucity of quality of life (QoL) assessments in studies evaluating patients treated for recurrent lateral patellar dislocation (LPD). The primary aim of this study was to investigate whether mental well-being is impaired in patients with chronic (recurrent) LPD and, if so, to assess whether the mental health-related QoL dimension improves equivalently to the physical-related QoL dimension after successful surgical treatment.MethodsThirty-eight patients with recurrent LPD over a mean course of the disease of 4.7 ± 3.9 years (1—18 years) prior to surgery were included. Generic health-related QoL (HRQoL) (Short Form 36; SF-36) and disease-specific QoL (Banff Patella Instability Instrument 2.0; BPII 2.0) were assessed preoperatively and after a mean follow-up of 3.5 ± 0.8 years (2 – 5 years) postoperatively.ResultsUntreated LPD significantly impacted the physical dimension of patients’ generic HRQoL and their disease-specific QoL. When compared to age-equivalent normative data sets, the mental HRQoL dimension was not reduced prior to operative treatment but increased during the follow-up period. Surgical treatment normalized the physical dimension of patients’ generic HRQoL and significantly improved their disease-specific QoL. However, BPII 2.0 values remained reduced, albeit patellae were successfully stabilized.ConclusionThe results of this study indicate that patients with recurrent LPD are generally in good mental health, although physical impairment is striking. Notwithstanding that surgery prevented further dislocations and normalized the generic HRQoL, the disease-specific QoL remained reduced as far as this can be interpreted without population-based data.Level of evidenceLevel IV; Retrospective case series.

Rare case of lateral dislocation of the elbow without distinct radiological signs

While the elbow joint dislocation is one of the most common dislocations, lateral dislocation of elbow is so rare. In this study, we described a 65-year-old woman with lateral elbow dislocation referred to Akhtar Hospital. With full range of motion in supination, pronation, and extension, as well as 60º flexion, the most important finding with this case was that the radiographic findings could not help surgeon to diagnose the lateral dislocation. Therefore, CT-scan was performed. After confirmation, closed reduction was done via a standard maneuver. The patient was followed up for 2 weeks and physiotherapy was ordered. According to this case, when there was an elbow trauma with unusual radiograph without any specific finding to confirm the lateral dislocation, it is recommended to perform CT-scan. The closed reduction and following physiotherapy also are essential for management of this condition.

Irreducible lateral knee dislocation in an 88 year old female: A case report

We present the unique case of a 88-year-old female who suffered a lateral knee dislocation of the right knee following a fall on a wet bathroom floor. Attempts at realignment via manipulation under anaesthesia (MUA) were unsuccessful, so the patient underwent an open reduction and the application of an external fixator to stabilise the knee. Knee dislocations are characterised by a high rate of neurovascular injuries, therefore special emphasis should be made on the prompt diagnosis and treatment of such injuries. Informed consent was obtained from the patient and family for the publication of the case report and all the figures included.

Treatment of Knee Osteochondral Fractures.

Osteochondral lesions (OCLs) that are frequently encountered in skeletally immature and adult patients are more common than once thought, and their incidence rate is rising. These lesions can appear in many synovial joints of the body, such as the shoulder, elbow, hip, and ankle, occurring most often in the knee. The term osteochondral lesion includes a vast spectrum of pathologies such as osteochondritis dissecans, osteochondral defects, osteochondral fractures, and osteonecrosis of the subchondral bone. When considering this, the term osteochondral fracture is preserved only for an osteochondral defect that combines disruption of the articular cartilage and subchondral bone. These fractures commonly occur after sports practice and are associated with acute lateral patellar dislocations. Many of these lesions are initially diagnosed by plain radiographs; however, a computed tomography (CT) scan or magnetic resonance imaging (MRI) can add significant value to the diagnosis and treatment. Treatment methods may vary depending on the location and size of the fracture, fragment instability, and skeletal maturity. The paper reports a 14-year-old boy case with an osteochondral fracture due to sports trauma. The medical approach involved an arthrotomy of the knee, drainage of the hematoma, two Kirschner wires (K-wires) for temporary fixation to restructure anatomic alignment, and a titanium Herbert screw fixing the fracture permanently. The patient had a favorable postoperative outcome with no residual pain, adequate knee stability, and a normal range of motion. The mobility of the knee was fully recovered.

Influence of Patellofemoral Anatomy on Outcomes of Isolated Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability.

Background:Patella alta and elevated tibial tubercle–trochlear groove (TT-TG) distance can predispose patients to lateral patellar dislocations and recurrent instability. Their influence on patient-reported outcomes (PROs) after medial patellofemoral ligament (MPFL) reconstruction is less clear.Hypothesis:We hypothesized that neither moderately increased TT-TG distance nor patella alta would negatively affect PROs after isolated MPFL reconstruction in patients with relatively normal patellar tracking (no large J-sign).Study Design:Cohort study; Level of evidence, 3.Methods:We identified patients who underwent isolated MPFL reconstruction at a single institution between 2008 and 2016. The decision to perform an isolated MPFL reconstruction was at the discretion of the operating surgeon but was not performed in the setting of a large J-sign. Patient characteristics and surgical details were collected, and patients completed the Norwich Patellar Instability Score, Knee injury and Osteoarthritis Outcome Score, and Marx activity score. Patellar height (Caton-Deschamps Index [CDI]) was assessed on preoperative lateral radiographs, and TT-TG distance was measured on preoperative axial magnetic resonance imaging (MRI) scans. Patients were grouped based on CDI and TT-TG distance, and outcomes were compared. Linear regression modeling was performed to determine whether patella alta or elevated TT-TG distance was associated with poorer PRO scores.Results:Of 165 knees in 152 patients who underwent isolated MPFL reconstruction, 115 patients (125 knees; 76%) with minimum 1-year follow-up were contacted at a mean of 5.2 years after surgery. Recurrent dislocation occurred in 5 of 125 knees (4%). Preoperative radiographs were available in 111 knees (89%), and preoperative MRI scans were available in 89 knees (71%). Mean CDI was 1.13, and 35% had a CDI ≥1.20. Mean TT-TG distance was 17.5 mm, and 26% had a TT-TG distance >20 mm. After adjusting for patient age, sex, body mass index, and graft choice, we observed that neither patella alta nor elevated TT-TG distance were associated with poorer PROs.Conclusion:Isolated MPFL reconstruction in the setting of moderately elevated TT-TG distance or patella alta was not associated with worse PROs in this cohort with relatively normal patellar tracking (no large J-sign).

Factors associated with acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time lateral patellar dislocation: A prospective magnetic resonance imaging study

ObjectivesTo identify risk factors of acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time lateral patellar dislocation (LPD). MethodsMagnetic resonance images were prospectively analyzed in 115 patients in an acute first-time LPD. Factors included gender, skeletal maturity, trochlear dysplasia, patellar height, and tibial tuberosity–trochlear groove (TT-TG) distance. Binary logistic regression analysis was carried out to identify the independent risk factors for the incidence of acute articular cartilage lesions of the patella and lateral femoral condyle in acute first-time LPD. ResultsThe incidence of acute articular cartilage lesion of the patella and lateral femoral condyle were 46.1% and 27% in acute first-time LPD, respectively. Univariate analysis revealed significantly higher incidence rate of acute articular cartilage lesion of the patella in male (P = 0.027), skeletally mature (P = 0.035), normal TT-TG distance (P = 0.043) and normal femoral trochlea (P = 0.031). Risk factors for the incidence of acute articular cartilage lesion of the patella were skeletally mature (odds ratio (OR): 2.324), normal TT-TG distance (OR: 2.824) and normal femoral trochlea (OR: 3.835). Univariate analysis revealed significantly higher incidence rate of acute articular cartilage lesion of the lateral femoral condyle in skeletally mature (P = 0.027) and normal femoral trochlea (P = 0.031). Risk factor for the incidence of acute articular cartilage lesion of the lateral femoral condyle was normal femoral trochlea (OR: 3.347). ConclusionsFor patients in acute first-time LPD, compared with other parameters, the normal femoral trochlea, normal TT-TG distance and skeletally mature are independent risk factors for the incidence of acute articular cartilage lesion of the patella, and the normal femoral trochlea is an independent risk factor for the incidence of acute articular cartilage lesion of the lateral femoral condyle.

Lateral Patellar Dislocation: A Critical Review and Update of Evidence-Based Rehabilitation Practice Guidelines and Expected Outcomes.

Nonoperative treatment of a lateral patellar dislocation produces favorable functional results, but as high as 35% of individuals experience recurrent dislocations. Medial patellofemoral ligament reconstruction is an effective treatment to prevent recurrent dislocations and yield excellent outcomes with a high rate of return to sport. Both nonoperative and postoperative rehabilitation should center on resolving pain and edema, restoring motion, and incorporating isolated and multijoint progressive strengthening exercises targeting the hip and knee. Prior to return to sports, both functional and isolated knee strength measurements should be used to determine leg symmetry strength and to utilize patient-reported outcome measures to assess the patient's perceived physical abilities and patellofemoral joint stability.

Flexion Dislocation After Limb Lengthening: Correction With Distal Femoral Osteotomy, Quadriceps Release, and Physeal-Sparing Medial Patellofemoral Ligament (MPFL) Reconstruction

Background: Patellar instability is a common clinical condition in skeletally immature individuals. Surgical treatment is considered when risk of recurrence is high. Indications: Distal femoral osteotomy is indicated in the setting of obligate flexion dislocation where femoral valgus contributes to a shortened lateral column, with concurrent quadriceps procedures considered for chronic contracture and medial patellofemoral ligament (MPFL) reconstruction for added stabilization. Technique Description: This procedure is performed in a stepwise manner as some components may not be necessary based on the patient’s specific anatomy. The procedure begins with a lateral iliotibial (IT) band soft tissue release or lengthening if possible. The distal femoral osteotomy is then performed utilizing a lateral opening wedge technique. Bone graft is placed in a structural fashion to maintain the correction while a locking plate is inserted. In patients with chronic lateral patellar dislocation, correction of bony alignment may not completely restore tracking. If lateral maltracking persists after further distal soft tissue release, a VY-lengthening quadricepsplasty can be considered. To perform this, the vastus lateralis (VL) is first released. In this patient, the patella was able to be stabilized centrally after VL release, and therefore, the VY-plasty was not performed. The soft tissue attachments for the final MPFL reconstruction are then prepared, including two at the superomedial and midbody of the patella and one at the adductor tendon. The whip-stitched graft is then passed through the adductor sling followed by the patellar periosteal tunnels with the knee in slight flexion to ensure centralization within the trochlear groove. Examination under anesthesia before final fixation of the reconstruction should demonstrate 1A lateral translation. Results: Correction of distal femoral valgus with osteotomy, in isolation or in combination with other patellar stabilizing procedures, has demonstrated significant improvement in patient-reported outcomes and reduced redislocation rates. However, large cohort studies are limited. Discussion/Conclusion: Both osseous and soft tissue abnormalities are important to consider in since they can contribute in varying degrees to patellar maltracking. Therefore, assessment of patellar tracking should be performed frequently to guide extent of surgical correction necessary.

The Effects of Early Range of Motion Versus Immobilization Following Acute First-Time Lateral Patellar Instability Episode: Randomized Control Trial

Background:The acute management of lateral patellar dislocations (LPD) typically consists of placing the patient in a knee immobilizer for 2 to 6 weeks, but it is not clear on how long these patients should be immobilized, if at all.Hypothesis/Purpose:The purpose of this study is to compare outcomes for patients following a rehabilitation protocol that is initiated with or without a short period of immobilization after sustaining a LPD.Methods:An IRB-approved prospective study was performed at a children’s hospital which included patients <18 years of age (mean = 14.22) diagnosed with LPD (<10 days). A total of 18 (14 females, 4 males) patients diagnosed with LPD were consented and enrolled in the study (Early ROM group = 11, Immobilization group = 7). Inclusion criteria for the study was history of knee instability, effusion or history of effusion, and (+) apprehension. Subjects were followed for 4 weeks and the following outcomes were assessed: knee ROM, isokinetic strength, Kujala, Pedi-IKDC, and Y balance scores. Split-plot (2x2) ANOVAs were conducted for each of the dependent variables with an alpha level set at .05 for the global tests and independent t-tests were run at baseline and 4 weeks.Results:There were no significant differences between groups at baseline. Knee flexion ROM showed a significant main effect of time (p≤.0005) and group (p=.012). Pedi-IKDC showed a significant main effect of time (p≤.0005) and group (p=.026). When comparing groups at 4 weeks, the early ROM group had significantly better scores in both the Kujala (means for both groups: 76.78 and 52.67), p=.049)), and the Pedi-IKDC (means for both groups: 68.85 and 40.88), p=.025)). There were no significant differences in isokinetic strength measures between the groups except for affected side knee flexion at 60 degrees/sec (p=.039) with the early ROM demonstrating higher strength. In addition, the affected side composite Y-balance scores were significantly better for the early ROM group (as compared to the immobilization group) at p=.031.Conclusion:Patients that underwent early ROM following LPD scored significantly better across patient derived outcome measures and functional outcomes at 4 weeks following the initial physical therapy evaluation when compared to a group that underwent a 2 week period of immobilization. Future studies should analyze longer term comparisons between groups to determine if this short term difference leads to long term differences or improved re-injury rates.

A Randomized Controlled Trial Comparing a Patella-Stabilizing, Motion-Restricting Knee Brace Versus a Neoprene Nonhinged Knee Brace After a First-Time Traumatic Patellar Dislocation

Background: A traumatic lateral patellar dislocation is a common injury in adolescents and young adults. The majority of first–time dislocations can be treated nonoperatively. Various types of knee braces are used for nonoperative treatment, but evidence on the most preferable bracing method is lacking. Purpose: To evaluate the efficacy of a patella–stabilizing, motion-restricting knee brace versus a neoprene nonhinged knee brace for the treatment of a first–time traumatic patellar dislocation at 3 years of follow–up. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 101 skeletally mature patients with a first–time traumatic patellar dislocation were enrolled in the study. After exclusion criteria were applied, 79 patients with a first–time traumatic patellar dislocation were randomized and allocated into 2 study groups: group A, with a patella–stabilizing, motion-restricting knee brace (hinged to allow knee range of motion [ROM] of 0°-30°) and group B, with a neoprene nonhinged knee brace (not restricting any knee motion). Both groups received similar physical therapy instructions and were advised to use the brace continuously for 4 weeks. Overall, 64 patients completed the trial. Results: The redislocation rate in group A was 34.4% (11/32) and in group B it was 37.5% (12/32) (risk difference, –3.1% [95% CI, –26.6% to 20.3%]; P = .794). Patients in group A had less knee ROM than those in group B at 4 weeks (90° vs 115°, respectively; P < .001) and 3 months (125° vs 133°, respectively; P = .028). Patients in group A had more quadriceps muscle atrophy than patients in group B at 4 weeks (24/32 vs 16/32, respectively; P = .048) and 3 months. At 6 months, patients in group B reported better functional outcomes than patients in group A (Kujala score mean difference, 4.6; P = .012), although no clinically relevant difference was found at 3 years. Conclusion: The use of a patella–stabilizing, motion-restricting knee brace for 4 weeks after a first–time traumatic patellar dislocation did not result in a statistically significant reduction in redislocations versus a neoprene nonhinged knee brace, although this trial was underpowered to detect more modest differences. Knee immobilization was associated with quadriceps muscle atrophy, less knee ROM, and worse functional outcomes in the first 6 months after the injury. Registration: NCT01344915 (ClinicalTrials.gov identifier).