The significance of arthroscopy and examination under anaesthesia in the diagnosis of fresh injury haemarthrosis of the knee joint

Three-dimensional magnetic resonance imaging-based statistical shape analysis and machine learning-based prediction of patellofemoral instability

This study performed three-dimensional (3D) magnetic resonance imaging (MRI)-based statistical shape analysis (SSA) by comparing patellofemoral instability (PFI) and normal femur models, and developed a machine learning (ML)-based prediction model. Twenty (19 patients) and 31 MRI scans (30 patients) of femurs with PFI and normal femurs, respectively, were used. Bone and cartilage segmentation of the distal femurs was performed and subsequently converted into 3D reconstructed models. The pointwise distance map showed anterior elevation of the trochlea, particularly at the central floor of the proximal trochlea, in the PFI models compared with the normal models. Principal component analysis examined shape variations in the PFI group, and several principal components exhibited shape variations in the trochlear floor and intercondylar width. Multivariate analysis showed that these shape components were significantly correlated with the PFI/non-PFI distinction after adjusting for age and sex. Our ML-based prediction model for PFI achieved a strong predictive performance with an accuracy of 0.909 ± 0.015, and an area under the curve of 0.939 ± 0.009 when using a support vector machine with a linear kernel. This study demonstrated that 3D MRI-based SSA can realistically visualize statistical results on surface models and may facilitate the understanding of complex shape features.

Epidemiology of patellar dislocations in the United States from 2001 to 2020: results of a national emergency department database

OBJECTIVES

Recent studies have shown an increasing incidence of patellar dislocations among children and adolescents. Updated, population-based studies of all patellar dislocations in the United States (US), however, are lacking. This study investigated recent trends in injury rates and demographics among patients sustaining patellar dislocations in the US from 2001 to 2020.

METHODS

This descriptive epidemiologic study retrospectively analyzed the National Electronic Injury Surveillance System (NEISS) database to identify cases of acute patellar dislocations presenting to US Emergency Departments (EDs) from 2001 to 2020. Annual, overall, and age-adjusted incidence rates (IRs, expressed per 100,000 at-risk person-years) and additional patient/injury characteristics were analyzed. Average annual percent change (AAPC) estimates are presented to indicate the magnitude/direction of trends in annual injury rates.

RESULTS

An estimated total of 159,529 patellar dislocations occurred over the study period for an overall IR of 2.58 (95% CI = 2.04-3.12). Accounting for population growth, the overall annual incidence increased significantly from 2.61 in 2001 to 3.0 in 2020 (AAPC = 2.8, p < 0.0001). When considering sex and age, statistically significant increases in annual IRs were observed among males aged 10-19 years (AAPC = 3.8, p < 0.0001), females aged 10-19 years (AAPC = 5.3, p < 0.0001), and females aged 20-29 years (AAPC = 3.5, p = 0.0152), while no significant changes were observed in any other age groups. Two-thirds of patellar dislocations involved sports-related injury mechanisms. The annual incidence of both sports-related and non-sports-related injuries increased significantly over the study period (sports-related: AAPC = 2.6, p = 0.0001; non-sports-related: AAPC = 3.4, p = 0.0001). Athletic patellar dislocations occurred most commonly in basketball and dance.

CONCLUSION

The number of patients sustaining patellar dislocations is increasing in the US. Similar increasing trends were observed in both males and females aged 10-19 years, whereas injury rates increased in the third decade only among females. A large percentage of injuries occur during athletic activity, but both sports- and non-sports-related patellar dislocations are on the rise.

A modified Delphi consensus statement on patellar instability: part I

Aims

The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Methods

A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered to be unanimous.

Results

Of 27 questions and statements on patellar instability, three achieved unanimous consensus, 14 achieved strong consensus, five achieved consensus, and five did not achieve consensus.

Conclusion

The statements that reached unanimous consensus were that an assessment of physeal status is critical for paediatric patients with patellar instability. There was also unanimous consensus on early mobilization and resistance training following nonoperative management once there is no apprehension. The statements that did not achieve consensus were on the importance of immobilization of the knee, the use of orthobiologics in nonoperative management, the indications for MPFC repair, and whether a vastus medialis oblique advancement should be performed.

The Use of Synthetic Graft for MPFL Reconstruction Surgery: A Systematic Review of the Clinical Outcomes

(1) Background: Acute patella dislocation (APD) is a prevalent knee injury, with rates between 5.8-77.8 per 100,000. APD often results in repeat lateral patella dislocations due to the instability of the medial patellofemoral ligament (MPFL). Non-operative treatments have a 50% recurrence rate. While autologous grafting for MPFL has been favored, surgeons are now exploring synthetic grafts. We aimed to assess the effectiveness of synthetic grafts in MPFL reconstruction surgeries for repeated patellar dislocations; (2) Methods: Our research was based on a thorough search from the National Institute of Health and Clinical Excellence Healthcare Databases, using the Modified Coleman Methodology Score for quality assessment; (3) Results: Six studies met the inclusion criteria. A total of 284 patients and 230 knees were included. Seventy-five percent of patients were graded to have excellent-good clinical outcomes using the Crosby and Insall Grading System. International Knee Documentation Committee score and Knee injury and Osteoarthritis Outcome Score scores showed 59% and 60% post-operative improvement, respectively; (4) Conclusions: All studies showed improvement in post-operative functional outcomes and report no serious adverse events. The 6 mm, LARS (Orthomedic Ltd., Dollard-des-Ormeaux, QC, Canada) proved to have the most improvement in post-operative outcomes when used as a double bundle graft.

The Novelty of Orthopedic Rehabilitation After Conservative Management for Patellar Dislocation With Partial Tear of Medial Meniscus and Early Osteoarthritis in a 31-Year-Old Female

Primary patellar dislocation or first-time patellar dislocation is the second most frequent cause of knee injuries which overall accounts for about 3% of other knee injuries. The patellofemoral joint is formed by the patella connecting to the femoral trochlea and creates both static and dynamic structures of the knee. There are basically three types of patellar dislocation: superior, lateral, and medial. The lateral dislocation is the most frequent one. Females are more vulnerable and are at higher risk than males. Muscular weakness or muscular imbalance leads to patellar instability, and ultimately to dislocation. The recurrence rate after primary patellar dislocation is 15-60%. This case report is of a 31-year-old female with patella dislocation with a medial meniscal tear and a case of early osteoarthritis for whom we planned goal-oriented physiotherapy rehabilitation week-wise and progressed every week. The assessment was taken before and after physiotherapy rehabilitation. The patient was managed conservatively with a long knee brace, and physiotherapy started after one month. Due to prolonged immobilization, the patient suffered from quadriceps muscle atrophy. The physiotherapist focused on biomechanism and got the expected results in pain reduction, regaining strength, and improving range of motion, and the patient was able to walk properly without taking any support after rehabilitation.

Incidence and concomitant chondral injuries in a consecutive cohort of primary traumatic patellar dislocations examined with sub-acute MRI

PURPOSE

To present age- and sex-specific cumulative annual incidences of primary traumatic lateral patellar dislocation (LPD) and to detail patient characteristics and concomitant chondral injuries including osteochondral fractures, as visualized on magnetic resonance imaging (MRI), in a large consecutive cohort of knee-injured individuals.

METHODS

Data on primary traumatic lateral patellar dislocations were collected from a large consecutive cohort of knee injuries examined with sub-acute MRI in a single centre with a well-defined catchment area. Annual incidences for different age-groups in relation to gender were calculated together with the risk of concomitant chondral and osteochondral injury, during sports and in general.

RESULTS

A total of 184 primary patellar dislocations were identified in the cohort of 1145 acute knee injuries (n=175) and surgical records (n=9). Knee MRI was performed within a median of six days of injury. Median age of patients with primary LPD was 16 years (interquartile range, 14-21; range, 9-47) and 41% were females. Males were significantly older than females at the time of injury (median age 17 vs. 15, P = 0.021) and sustained their primary LPD during sports more often than females (65 vs. 40%, P < 0.001). Primary LPD occurred most frequently at the age of 13 to 15 years where the annual incidence was 125 (95% CI, 96-160) per 100,000 persons. The overall annual incidence of primary LPD was 14 (95% CI, 12-16) per 100,000 persons, with a predominance of males versus females (17 vs. 11, P = 0.01). Concomitant lesions to joint surfaces were displayed on MRI or during surgery in 75 (43%) knees. Osteochondral fractures were seen in 32 knees (18%). We found no statistically significant difference in the risk of osteochondral fracture between those injured during sports or during leisure activity (14 vs. 24%, P = 0.08).

CONCLUSIONS

The annual incidence of first-time patellar dislocation was found to be 14 per 100,000 individuals with the highest incidence found among those aged 13-15 years. Primary LPD was more common among males and was sustained during sports activity in 55% of the cases. Associated injuries to the chondral surfaces should be expected in 43% of knees with primary LPD where 18% represent osteochondral fractures.

Medial Patellofemoral Ligament Reconstruction in Obese Patients Results in Low Complication Rates and Improved Subjective Outcomes

Purpose

To compare outcomes, activity scores, and complication rates of obese and non-obese patients undergoing medial patellofemoral ligament (MPFL) reconstruction.

Methods

A retrospective review identified patients undergoing MPFL reconstruction for recurrent patellofemoral instability. Patients were included if they had undergone MPFL reconstruction and had follow-up for a minimum of 6 months. Patients were excluded if they underwent surgery less than 6 months earlier, had no outcome data recorded, or underwent concomitant bony procedures. Patients were divided into 2 groups based on body mass index (BMI): BMI of 30 or greater and BMI less than 30. Presurgical and postsurgical patient-reported outcomes including Knee Injury and Osteoarthritis Outcome Score (KOOS) domains and the Tegner score were collected. Complications requiring reoperation were recorded. P < .05 was defined as a statistically significant difference.

Results

A total of 55 patients (57 knees) were included. There were 26 knees with a BMI of 30 or greater and 31 knees with a BMI less than 30. There were no differences in patient demographic characteristics between the 2 groups. Preoperatively, no significant differences were found in KOOS subscores or Tegner scores (P = .21) between groups. At minimum 6-month follow-up (range, 6.1-70.5 months), patients with a BMI of 30 or greater showed statistically significant improvements in the KOOS Pain, Activities of Daily Living, Symptoms, and Sport/Recreation subscores. Patients with a BMI less than 30 showed a statistically significant improvement in the KOOS Quality of Life subscore. The group with a BMI of 30 or greater had significantly lower KOOS Quality of Life (33.34 ± 19.10 vs 54.47 ± 28.00, P = .03) and Tegner (2.56 ± 1.59 vs 4.78 ± 2.68, P = .05) scores. Complication rates were low, with 2 knees (7.69%) requiring reoperation in the cohort with a BMI of 30 or greater and 4 knees (12.90%) requiring reoperation in the cohort with a BMI less than 30, including 1 reoperation for recurrent patellofemoral instability (P = .68).

Conclusions

In this study, MPFL reconstruction in obese patients was safe and effective, with low complication rates and improvements in most patient-reported outcomes. Compared with patients with a BMI less than 30, obese patients had lower quality-of-life and activity scores at final follow-up.

Level of Evidence

Level III, retrospective cohort study.

Predictors of Occult Chondral Injury Sustained After a Primary Patellar Dislocation

Background and objective

Primary patellar dislocations can concomitantly involve osteochondral injuries for which prompt recognition is paramount for joint preservation. These injuries can be missed on radiographs, necessitating MRI examinations. In this study, we aimed to identify patient parameters that correlate with occult osteochondral injuries.

Methods

Patients were retrospectively identified between 2015 and 2020 through a chart review. The inclusion criteria were as follows: patients diagnosed with a primary patellar dislocation with three radiographic views and an MRI of the injured knee. Demographic and radiographic data were evaluated.

Results

A total of 61 patients met the inclusion criteria. There were no statistically significant demographic differences between patients with osteochondral injuries and those without (p>0.05). Seven knees (88%) with an osteochondral lesion and 20 (38%) without had an effusion (p=0.02). There was no association in terms of ligamentous laxity (p=0.49), Caton-Deschamps index (CDI) (p=0.68), sulcus angle (SA) (p=0.68), congruence angle (CA) (p=0.56), and lateral patellofemoral angle (LPFA) (p=0.25) between patients with and without an occult osteochondral injury.

Conclusion

Among the parameter examined, the presence of an effusion was the only one that correlated with the presence of occult osteochondral injury in our cohort.

Return to Play After Medial Patellofemoral Ligament Reconstruction: A Systematic Review

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction is being performed more frequently in athletes experiencing recurrent patellar instability.

PURPOSE/HYPOTHESIS

The purpose was to systematically review the evidence in the orthopaedic sports medicine literature to determine both the rate and timing of return to play after MPFL reconstruction and the rate of further patellar instability. Our hypothesis was that there would be a high rate of return to play after MPFL reconstruction.

STUDY DESIGN

Systematic review.

METHODS

A systematic literature search was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, which utilized EMBASE, MEDLINE, and the Cochrane Library databases. Inclusion criteria for literature included clinical studies reporting on return to play after MPFL reconstruction. Rate of return to play, level of return, timing of return, rate of recurrent instability, and patient-reported outcomes were evaluated. Statistical analysis was performed using SPSS.

RESULTS

Our review found 27 studies including 1278 patients meeting our inclusion criteria. The majority of patients were women (58%), and the total group had a mean age of 22.0 years and a mean follow-up of 39.3 months. The overall rate of return to play was 85.1%, with 68.3% returning to the same level of play. The average time to return to play was 7.0 months postoperatively. The rate of recurrent instability events following reconstruction was 5.4%. There was an improvement in both mean visual analog scale, pain scores (preoperative: 4.3, postoperative: 1.6) and Tegner activity scores (preoperative: 4.8, postoperative: 5.5).

CONCLUSION

The overall rate of return to play was high after MPFL reconstruction for the treatment of recurrent patellar instability. However, a relatively high percentage of those patients were unable to return to their preoperative level of sport. Additionally, there was a moderate time taken to return to play, at approximately 7 months after the procedure.

Medial patellofemoral ligament reconstruction using an autograft or allograft for patellar dislocation: a systematic review

Purposes

The purpose of this study is to review the use of an allograft or autograft in medial patellofemoral ligament (MPFL) reconstruction.

Materials and methods

Various electronic databases were searched for relevant articles published from January 2000 to September 2017 that evaluated clinical outcomes of MPFL reconstruction using an autograft or allograft. Data search, extraction, analysis, and quality assessments were performed based on Cochrane Collaboration guidelines.

Results

The study of 21 autografts and one allograft was included in this review. Although direct comparative studies were unavailable, the Kujala score and subjective results were reported in the majority of these studies. While the use of an autograft for MPFL reconstruction yielded satisfactory clinical outcomes with few perioperative complications, no new outcome has been drawn from the use of allografts.

Conclusions

Although many studies have shown favorable clinical results for MPFL reconstruction using an autograft, the clinical results of MPFL reconstruction using an allograft have not yet been sufficient to achieve meaningful clinical results due to low levels of evidence. Direct comparisons were not conducted because there were very few studies on allografts; thus, further research in this area should be performed in the future.

Electronic supplementary material

The online version of this article (10.1186/s43019-019-0008-0) contains supplementary material, which is available to authorized users.

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 Repair Versus Reconstruction for Recurrent Patellar Instability: Two-Year Results of an Algorithm-Based Approach

Background:

Patellar instability remains a challenging problem for both the patient and surgeon. Medial patellofemoral ligament (MPFL) repair has historically had poor results, and due to this, there is currently a trend toward reconstruction.

Purpose/Hypothesis:

This study was undertaken to investigate experience with repair versus reconstruction of the MPFL using a multifactorial treatment algorithm approach. Our hypothesis was that there will be no significant difference in outcome scores between patients in the MPFL repair and reconstruction groups.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 24 patients with recurrent (≥2) lateral patellar dislocations were included. All had failed nonoperative treatment for more than 6 months, and all were observed for a minimum of 2 years. First, magnetic resonance imaging (MRI) was used to find the location of the MPFL tear. A tilt test was used to determine whether a lateral retinacular lengthening was required to allow the patella to have neutral tilt. If the MRI showed a tibial tubercle–trochlear groove (TT-TG) distance greater than 20 mm, a tibial tubercle osteotomy (TTO) was recommended. An MPFL reconstruction was performed if the entire ligament was inadequately visualized on MRI or if it was torn from both insertion sites. Failure was defined as recurrent lateral patellar instability after surgery. As a secondary outcome measure, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, and Tegner score were calculated.

Results:

All patients were evaluated with a mean follow-up of 51 months (range, 25-79 months). Sixteen patients initially underwent MPFL repair, 8 underwent reconstruction, and 3 also underwent TTO. MPFL reconstructions were performed in all patients who underwent TTO. One MPFL repair was to the anatomic femoral origin and 15 were to the patellar insertion corresponding to the site of tearing on MRI. A lateral retinacular lengthening was performed in 21 patients. There was 1 failure in the repair group (6%) and none in the reconstruction group. However, the patient who failed had a TT-TG distance of 26 mm but refused a TTO. She subsequently underwent revision with a TTO and MPFL reconstruction and did not have any further instability events. There were no significant differences between groups for any of the secondary outcome scores.

Conclusion:

Using an algorithm-based approach, MPFL repair or reconstruction may lead to clinically acceptable results at 2-year follow-up.

Acute Osteochondral Fractures in the Lower Extremities - Approach to Identification and Treatment

Chondral and osteochondral fractures of the lower extremities are important injuries because they can cause pain and dysfunction and often lead to osteoarthritis. These injuries can be misdiagnosed initially which may impact on the healing potential and result in poor long-term outcome. This comprehensive review focuses on current pitfalls in diagnosing acute osteochondral lesions, potential investigative techniques to minimize diagnostic errors as well as surgical treatment options. Acute osteochondral fractures are frequently missed and can be identified more accurately with specific imaging techniques. A number of different methods can be used to fix these fractures but attention to early diagnosis is required to limit progression to osteoarthritis. These fractures are common with joint injuries and early diagnosis and treatment should lead to improved long term outcomes.

Acute traumatic patellar dislocation

Inaugural traumatic patellar dislocation is most often due to trauma sustained during physical or sports activity. Two-thirds of acute patellar dislocations occur in young active patients (less than 20 years old). Non-contact knee sprain in flexion and valgus is the leading mechanism in patellar dislocation, accounting for as many as 93% of all cases. The strong displacement of the patella tears the medial stabilizing structures, and notably the medial patellofemoral ligament (MPFL), which is almost always injured in acute patellar dislocation, most frequently at its femoral attachment. Lateral patellar glide can be assessed with the knee in extension or 20° flexion. Displacement by more than 50% of the patellar width is considered abnormal and may induce apprehension. Plain X-ray and CT are mandatory to diagnose bony risk factors for patellar dislocation, such as trochlear dysplasia or increased tibial tubercle-trochlear groove distance (TT-TG), and plan correction. MRI gives information on cartilage and capsulo-ligamentous status for treatment planning: free bodies or osteochondral fracture have to be treated surgically. If patellar dislocation occurs in an anatomically normal knee and osteochondral fracture is ruled out on MRI, non-operative treatment is usually recommended.

A statistical shape model of trochlear dysplasia of the knee

BACKGROUND

Trochlear dysplasia is known as the primary predisposing factor for patellar dislocation. Current methods to describe trochlear dysplasia are mainly qualitative or based on a limited number of discrete measurements. The purpose of this study is to apply statistical shape analysis to take the full geometrical complexity of trochlear dysplasia into account.

METHODS

Statistical shape analysis was applied to 20 normal and 20 trochlear dysplastic distal femur models, including the cartilage.

RESULTS

This study showed that the trochlea was anteriorized, proximalized and lateralized and that the mediolateral width and the notch width were decreased in the trochlear dysplastic femur compared to the normal femur. The first three principal components of the trochlear dysplastic femurs, accounting for 79.7% of the total variation, were size, sulcus angle and notch width. Automated classification of the trochlear dysplastic and normal femora achieved a sensitivity of 85% and a specificity of 95%.

CONCLUSIONS

This study shows that shape analysis is an outstanding method to visualise the location and magnitude of shape abnormalities. Improvement of automated classification and subtyping within the trochlear dysplastic group are expected when larger training sets are used.

CLINICAL RELEVANCE

Classification of trochlear dysplasia, especially borderline cases may be facilitated by automated classification. Furthermore, the identification of a decreased notch width in association with an increased sulcus angle can also contribute to the diagnosis of trochlear dysplasia.

Primary traumatic patellar dislocation

Acute traumatic patellar dislocation is a common injury in the active and young adult populations. MRI of the knee is recommended in all patients who present with acute patellar dislocation. Numerous operative and non-operative methods have been described to treat the injuries; however, the ideal management of the acute traumatic patellar dislocation in young adults is still in debate. This article is intended to review the studies to the subjects of epidemiology, initial examination and management.

Acute traumatic and sports-related osteochondral injury of the pediatric knee

Adolescents are predisposed to osteochondral (OC) injuries in the knee. The medial facet of the patella, the femoral trochlea, and the lateral femoral condyle are the most common sites of injury. Most of these injuries are classically traumatic but noncontact injuries. Surgery is warranted in most cases of OC fracture. Depending on size, condition, and location of the lesion, options include OC fragment reduction and internal fixation or excision and cartilage resurfacing. Understanding of how to diagnose and treat OC fractures will help optimize outcomes.

The relation of the femoral physis and the medial patellofemoral ligament

PURPOSE

The purpose of this study was to determine the origin of the medial patellofemoral ligament (MPFL) relative to the distal femoral physis by use of an indirect radiologic method.

METHODS

Twenty radiographs from adolescent male and female subjects (10 samples from each group) were used. The subjects studied were all skeletally immature, with an open distal femoral physis. The radiographic technique described by Schöttle et al. was used to identify the origin of the MPFL. Imaging software was used to determine the approximate distance of the MPFL origin relative to the open growth plate of the subjects involved.

RESULTS

In all 20 radiographs the medial physis was found to be distal to the average MPFL insertion point. The mean location for the female physis was 2.7 +/- 1.1 mm distal to the MPFL origin. The mean location for the male physis was 4.6 +/- 2.4 mm distal to the MPFL origin.

CONCLUSIONS

Based on an indirect radiographic technique, we found that the origin of the MPFL is just proximal to the femoral physis.

CLINICAL RELEVANCE

This information may be useful when planning medial retinacular surgical procedures in skeletally immature athletes to help avoid clinically significant physeal injury.

Approach to knee effusions

The presence of an intra-articular knee effusion requires an extensive differential diagnosis and a systematic diagnostic approach. Pediatric knee effusions occur most commonly as acute hemarthroses after traumatic injury. However, the knee joint is susceptible to effusions secondary to a wide variety of atraumatic causes. Special attention is required in the atraumatic effusion to distinguish features of infectious, postinfectious, rheumatologic, hematologic, vasculitic, and malignant disease. This review discusses the various etiologies of both traumatic and atraumatic pediatric knee effusions highlighting the historical, physical examination, and laboratory characteristics to aid the emergency provider in diagnosis and initial management.

Acute rotational trauma to the knee: poor agreement between clinical assessment and magnetic resonance imaging findings

OBJECTIVES

To determine the incidence of anterior cruciate ligament (ACL) injuries in the general population; the pathology associated with a knee sprain verified by magnetic resonance imaging (MRI); and the agreement between clinical findings and MRI.

MATERIAL AND METHODS

Inclusion criterion was an acute rotational trauma to the knee associated with effusion. One hundred and fifty-nine consecutive patients, mean age 27 years and 36% women, were included after clinical assessment at the orthopedic emergency unit. Patients were referred to an MRI examination (1.0 or 1.5 T) performed within a median of 8 days of the initial visit.

RESULTS

The annual incidence of MRI verified ACL injuries was 0.81/1000 inhabitants aged 10-64 years. Fifty-six percent (n=89) of those included had sustained an ACL injury of whom 38% had an associated medial meniscus tear. There was a poor agreement between initial clinical antero-posterior laxity and MRI verified presence of an ACL tear (kappa 0.281). Every second patellar dislocation was diagnosed as a ligament injury.

CONCLUSION

Our findings indicate that the incidence of ACL injuries is higher than previously described. We also show that the first clinical examination after an acute knee trauma has a low diagnostic value. Further assessment with MRI improves the chances of a correct diagnosis of intraarticular pathology and is recommended in the early phase after a rotational knee trauma.

First-time traumatic patellar dislocation: a systematic review

Acute patellar dislocations can result in patellar instability, pain, recurrent dislocations, decreased level of sporting activity, and patellofemoral arthritis. The initial management of a first-time traumatic patellar dislocation is controversial with no evidence-based consensus to guide decision making. Most first-time traumatic patellar dislocations have been traditionally treated nonoperatively; however, there has been a recent trend in initial surgical management. We performed a systematic review of Level I-IV studies to make evidence-based medicine recommendations on how a clinician should approach the diagnosis and treatment of a first-time traumatic dislocation. More specifically we answer the primary question of when initial treatment should consist of operative versus closed management. Based on the review of 70 articles looking at study design, mean followup, subjective and validated outcome measures, redislocation rates, and long-term symptoms, we recommend initial nonoperative management of a first-time traumatic dislocation except in several specific circumstances. These include the presence of an osteochondral fracture, substantial disruption of the medial patellar stabilizers, a laterally subluxated patella with normal alignment of the contralateral knee, or a second dislocation, or in patients not improving with appropriate rehabilitation.

Acute traumatic primary patellar dislocation: long-term results comparing conservative and surgical treatment

OBJECTIVE

This report evaluates the subjective, clinical, and functional long-term results comparing surgical and conservative treatment in patients with a primary traumatic patellar dislocation.

DESIGN AND SETTING

This retrospective clinical study focuses on patients with primary acute traumatic patellar dislocation. Patients with radiologic signs indicative of a predisposition for recurrent patellar instability were excluded from this study.

PATIENTS

A total of 126 patients were examined a mean of 8.1 years after initial treatment of their primary patellar dislocation.

INTERVENTIONS AND MAIN OUTCOME MEASUREMENTS

Patients were retrospectively divided into groups with conservative therapy (n = 63), diagnostic arthroscopy only (n = 20), immediate surgical reconstruction of the parapatellar ligament complex (n = 37), and refixation of osteochondral fragments (n = 6). Redislocation and resurgery rate, activity level, and subjective, clinical, and functional results were evaluated in these patients, and the outcomes in these groups were compared.

RESULTS

In the long term, functional results (as expressed in the Lysholm score) were excellent or good in 85% of the patients, and good subjective results were reported by 71%, but follow-up revealed a recurrence rate of 26% in the total study population. The high activity level before the initial trauma could not be completely regained after treatment. There was no significant difference between the surgically and conservatively treated groups in the redislocation and reoperation rates, level of activity, or functional and subjective outcomes.

CONCLUSIONS

Even with a focus on acute traumatic etiology and when factors predisposing to recurrent instability are largely excluded, the redislocation rate after treatment of acute patellar dislocation is still high, despite good clinical and subjective results. Conservative management seems to be the treatment of choice in patients with acute patellar dislocation, provided that the generally accepted indications for surgery, such as evidence of osteochondral fragments and major defects of the parapatellar ligament complex, are given due consideration.

The causes and mechanisms of meniscal injuries in the sporting and non-sporting environment in an unselected population

The aim of this study was to establish the aetiology and circumstances of meniscal injuries in the general adult population. We studied a group of patients who underwent arthroscopy under the care of the same surgeon between 1991 and 1998 (1236 patients). The study group included 392 patients, aged 18 to 60 years, with no previous knee injury, surgery or arthritis, with normal X-rays and meniscal injuries proven at arthroscopy. No professional athletes were included in the study group. The patients with Sports injuries (mean age 33 years) accounted for 32.4% of cases. The patients with Non-sporting injuries (mean age 41 years) accounted for 38.8% of tears. 71.9% of these happened in activities of daily living (and half of this group sustained their tear by squatting or ascent from this position). Patients without identifiable injury (mean age 43 years) represented 28.8% of cases. Male:Female ratio was 4:1. Medial tears accounted for two thirds of cases. This type of study, not undertaken since the advent of MRI or arthroscopy, shows that in the general population, two thirds of meniscal tears occurred in the absence of sporting activities, frequently within the ambit of every day activities and in the absence of the classic injury mechanism. Ascent from a squat is a common mechanism of injury not widely described or emphasised.

Acute traumatic hemarthrosis of the knee. Is routine arthroscopic examination necessary? A study of 320 consecutive patients

BACKGROUND AND AIMS

Distortions and contusions of the knee are common. Fairly often they will result in hemarthrosis. The purpose of this study was to evaluate the findings in patients with acute traumatic hemarthrosis of the knee and based on these findings estimate the necessity of acute arthroscopic examination.

MATERIAL AND METHODS

A total of 320 patients were examined arthroscopically between the years 1994 to 96 in the Turku University Hospital. Patients with other than chondral or osteochondral fractures were excluded.

RESULTS

The most common arthroscopic findings were rupture of the ACL (45%), dislocation of the patella (23%) and meniscal tear (21%). In only 113 (35%) cases an immediate therapeutic procedure was performed in addition to the arthroscopic examination.

CONCLUSIONS

Based on our findings we believe that routine arthroscopic examination is not necessary in patients with acute traumatic hemarthrosis of the knee. In our opinion the patient should be examined and followed by an orthopedic surgeon and if a lesion requiring operative treatment is diagnosed or suspected, an arthroscopic examination should be scheduled. The timing of the procedure should be such that all possible lesions encountered can be treated in the same operation.

Surgery in acute patellar dislocation--evaluation of the effect of injury mechanism and family occurrence on the outcome of treatment

A retrospective study was made of 270 patients and 284 knees with acute patellar dislocation treated operatively. The mean follow up time was 4.1 years. Medical history revealed 21.1% of cases with previous dislocations and 15.6% of cases with family occurrence of patellar dislocation. The dislocation resulted from an athletic performance in 41.5% of cases. The sport events most often associated with patellar dislocation were soccer, gymnastics, and ice hockey. All cases were treated with reefing of medial capsule. Release of lateral patellar retinacula was performed in 243 cases. Two cases were treated primarily with the Elmslie-Roux-Trillat procedure. The subjective result of operative treatment was better and the redislocation rate was lower if the injury mechanism was traumatic rather than non-traumatic and if there was no history for family occurrence of patellar dislocation.

Acute hemarthrosis of the knee in children

The purpose of this study was to determine the cause of acute hemarthrosis of the knee in a prospective pediatric patient population. Between December 1988 and August 1991, 21 consecutive children who were seen with an acute traumatic hemarthrosis of the knee had an arthroscopic evaluation. The average age of the children at the time of injury was 14 years, 3 months (range, 10 to 17 years). The mechanism of injury was a torsional strain to the knee in 12 (71%) of the 17 patients who could accurately remember the injury. The initial evaluation included a history, physical examination, and anteroposterior, lateral, sunrise, and comparison radiographs. The arthroscopic procedure was performed under general anesthesia, and the arthroscopic findings were compared with preoperative findings. During arthroscopic examination, an osteochondral fracture of the lateral femoral condyle or patella was identified in 14 (67%) of the 21 patients. Preoperative radiographs failed to identify the fracture in 5 (36%) of the 14 patients who had an osteochondral fracture. The anterior cruciate ligament was visualized and probed; an injury was found in only two cases (10%). We concluded that in children an acute traumatic hemarthrosis reflects a major injury to the knee. The children in this study had a high frequency of osteochondral fractures; ACL injuries were found in only two patients. Because of the unreliable nature of radiographic evaluation, arthroscopic evaluation is a valuable tool in differential diagnosis and treatment of acute hemarthrosis of the knee.

Posterior cruciate ligament injuries in trauma patients

The purpose of this article is to evaluate the incidence of posterior cruciate ligament (PCL) injuries in trauma patients with acute hemarthrosis of the knee. Sixty-one acute knee injuries underwent examination under anesthesia and diagnostic arthroscopy at a tertiary care trauma center over an 11-month period. PCL injuries occurred in 44% (27 of 61) acute knee injuries; 81.5% (22 of 27) were trauma patients and 18.5% (five of 27) were sports related. Higher energy mechanisms of injury may account for the difference. Isolated PCL injuries were rare [7.5% (two of 27)], whereas 92.5% (25 of 27) of PCL injuries occurred in combination with other ligament injuries. Trauma patients have a higher incidence of PCL injuries than does the athletic population. Acute knee hemarthrosis in trauma patients should elevate suspicion for PCL injuries. Arthroscopy is a valuable tool for PCL evaluation and surgical planning.

Incidence and diagnosis of anterior cruciate injuries in the accident and emergency department

A total of 220 consecutive young adults with a traumatic effusion of the knee joint, seen initially in the accident and emergency department, have been reviewed in a weekly orthopaedic acute knee clinic. Of the patients, 80 per cent were seen within 3 days of the injury, and all patients were seen within 8 days of the injury. There were 62 patients (28 per cent) with damage to the anterior cruciate ligament (ACL), of whom 37 patients (17 per cent) had acute complete ACL tears. There were 92 haemarthroses in this series, in which there was a high incidence of ACL damage. The Lachman test was used in this study and identified 73 per cent of the acute complete ACL tears preoperatively and all the chronic ACL injuries. Acute ACL injuries can be diagnose early provided adequate resources are available to provide clinic and theatre facilities. Early diagnosis enables the patients to be given clear advice on future job and sports prospects and allows selection of patients most likely to benefit from augmented repair of the ligament. Associated meniscal lesions can also be identified and treated at an early stage.