Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.

Patellofemoral pain: proximal, distal, and local factors, 2nd International Research Retreat.

A new patellofemoral arthroplasty is described, based on a previous design of total knee arthroplasty. The indications are for patients with specific isolated patellofemoral disease with advanced chondral or arthritic damage. The design and technique of insertion is detailed. Three hundred six patellofemoral arthroplasties have been done in 240 patients. The initial results show a high level of pain relief and improvement in function. Two-year followup is available for treatment of 124 knees and 5-year followup is available for treatment of 33 knees. There has been no deterioration in pain or function with followup to 5 years, and there were no late complications attributable to the arthroplasty. Disease progression in the tibiofemoral joint has occurred in 14 patients (16 knees, 5%) requiring revision in 10 of these patients (11 knees, 3.6%). Persistent anterior knee pain was recorded in 14 knees (4%). The short-term results using this new design were better than those of the prosthesis that we used previously, especially concerning malalignment and wear. It offers a reasonable alternative to total knee replacement in the small group of patients with isolated patellofemoral disease.

Development and early results of a new patellofemoral arthroplasty : Patellofemoral arthritis and arthroplasty

Glenoid spherical orientation and version.

BACKGROUND
Arthroscopic partial meniscectomy is one of the most common orthopedic procedures, yet rigorous evidence of its efficacy is lacking.


METHODS
We conducted a multicenter, randomized, double-blind, sham-controlled trial in 146 patients 35 to 65 years of age who had knee symptoms consistent with a degenerative medial meniscus tear and no knee osteoarthritis. Patients were randomly assigned to arthroscopic partial meniscectomy or sham surgery. The primary outcomes were changes in the Lysholm and Western Ontario Meniscal Evaluation Tool (WOMET) scores (each ranging from 0 to 100, with lower scores indicating more severe symptoms) and in knee pain after exercise (rated on a scale from 0 to 10, with 0 denoting no pain) at 12 months after the procedure.


RESULTS
In the intention-to-treat analysis, there were no significant between-group differences in the change from baseline to 12 months in any primary outcome. The mean changes (improvements) in the primary outcome measures were as follows: Lysholm score, 21.7 points in the partial-meniscectomy group as compared with 23.3 points in the sham-surgery group (between-group difference, -1.6 points; 95% confidence interval [CI], -7.2 to 4.0); WOMET score, 24.6 and 27.1 points, respectively (between-group difference, -2.5 points; 95% CI, -9.2 to 4.1); and score for knee pain after exercise, 3.1 and 3.3 points, respectively (between-group difference, -0.1; 95% CI, -0.9 to 0.7). There were no significant differences between groups in the number of patients who required subsequent knee surgery (two in the partial-meniscectomy group and five in the sham-surgery group) or serious adverse events (one and zero, respectively).


CONCLUSIONS
In this trial involving patients without knee osteoarthritis but with symptoms of a degenerative medial meniscus tear, the outcomes after arthroscopic partial meniscectomy were no better than those after a sham surgical procedure. (Funded by the Sigrid Juselius Foundation and others; ClinicalTrials.gov number, NCT00549172.).

Arthroscopic Partial Meniscectomy versus Sham Surgery for a Degenerative Meniscal Tear

Arthroscopic superior capsule reconstruction (ASCR) using fascia lata autograft is a new surgical technique developed to overcome irreparable rotator cuff tears. There is little information about graft tear after ASCR and its impact on clinical outcome. This study is to investigate the graft tear rate, pattern of failure, and its correlation with clinical outcomes after arthroscopic superior capsule reconstruction (ASCR). From June 2013 to June 2016, 31 shoulders in 31 consecutive patients (mean 65.3 years) underwent ASCR using fascia lata autograft for irreparable large-to-massive tears. Magnetic resonance imaging (MRI) was performed before surgery and at mean 12.8 months (12–24 months) after surgery to assess fatty infiltration progression and graft integrity. Graft tear was defined as the loss of graft continuity and was categorized as medial and lateral rows according to the failure location. Acromiohumeral distance (AHD) was pre- and postoperatively measured with the standard radiograph. Pain visual analog scale (VAS) score, American Shoulder and Elbow Surgeons (ASES) score, constant score, and physical examination were used to assess clinical outcomes. Average follow-up was 15 months (range 12–24 months) after surgery. Mean active forward elevation increased from 133° to 146° (P = 0.011). Mean VAS score, ASES score, and constant score significantly improved: from 6 to 2.5, 54.4 to 73.7, and 51.7 to 63.7, respectively (P < 0.001). There was no remarkable progression of fatty infiltration after surgery. AHD increased from 5.3 mm preoperatively to 6.4 mm postoperatively (P < 0.016). Nine patients (29%) showed graft tear on follow-up MRI: 7 and 2 at the medial and lateral rows, respectively. Although the intact graft group showed better outcomes than the graft tear group (pain VAS score 2.3 vs. 3.0; ASES score 74.1 vs. 69.8; constant score 63.4 vs. 57.9), the results were not statistically significant. Graft tear rate after ASCR assessed by MRI was 29%, and failures mostly occurred at the medial row. The graft tear group showed clinical improvement despite the recurred superior capsule defect. IV, case series, treatment study.

Graft tears after arthroscopic superior capsule reconstruction (ASCR): pattern of failure and its correlation with clinical outcome.

Objective To assess the benefit of arthroscopic partial meniscectomy (APM) in adults with a meniscal tear and knee pain in three defined populations (taking account of the comparison intervention): (A) all patients (any type of meniscal tear with or without radiographic osteoarthritis); (B) patients with any type of meniscal tear in a non-osteoarthritic knee; and (C) patients with an unstable meniscal tear in a non-osteoarthritic knee. Design Systematic review and meta-analysis. Datasources A search of MEDLINE, Embase, CENTRAL, Scopus, Web of Science, Clinicaltrials.gov and ISRCTN was performed, unlimited by language or publication date (inception to 18 October 2018). Eligibilitycriteria Randomised controlled trials performed in adults with meniscal tears, comparing APM versus (1) non-surgical intervention; (2) pharmacological intervention; (3) surgical intervention; and (4) no intervention. Results Ten trials were identified: seven compared with non-surgery, one pharmacological and two surgical. Findings were limited by small sample size, small number of trials and cross-over of participants to APM from comparator interventions. In group A (all patients) receiving APM versus non-surgical intervention (physiotherapy), at 6–12 months, there was a small mean improvement in knee pain (standardised mean difference [SMD] 0.22 [95% CI 0.03 to 0.40]; five trials, 943 patients; I2 48%; Grading of Recommendations Assessment, Development and Evaluation [GRADE]: low), knee-specific quality of life (SMD 0.43 [95% CI 0.10 to 0.75]; three trials, 350 patients; I2 56%; GRADE: low) and knee function (SMD 0.18 [95% CI 0.04 to 0.33]; six trials, 1050 patients; I2 27%; GRADE: low). When the analysis was restricted to people without osteoarthritis (group B), there was a small to moderate improvement in knee pain (SMD 0.35 [95% CI 0.04 to 0.66]; three trials, 402 patients; I2 58%; GRADE: very low), knee-specific quality of life (SMD 0.59 [95% CI 0.11 to 1.07]; two trials, 244 patients; I2 71%; GRADE: low) and knee function (SMD 0.30 [95% CI 0.06 to 0.53]; four trials, 507 patients; I2 44%; GRADE: very low). There was no improvement in knee pain, function or quality of life in patients receiving APM compared with placebo surgery at 6–12 months in group A or B (pain: SMD 0.08 [95% CI −0.24 to 0.41]; one trial, 146 patients; GRADE: low; function: SMD −0.08 [95% CI −0.41 to 0.24]; one trial, 146 patients; GRADE: high; quality of life: SMD 0.05 [95% CI −0.27 to 0.38]; one trial; 146 patients; GRADE: high). No trials were identified for people in group C. Conclusion Performing APM in all patients with knee pain and a meniscal tear is not appropriate, and surgical treatment should not be considered the first-line intervention. There may, however, be a small-to-moderate benefit from APM compared with physiotherapy for patients without osteoarthritis. No trial has been limited to patients failing non-operative treatment or patients with an unstable meniscal tear in a non-arthritic joint; research is needed to establish the value of APM in this population. Protocol registration number PROSPERO CRD42017056844.

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Arthroscopic partial meniscectomy for meniscal tears of the knee: a systematic review and meta-analysis

Patella subluxation assessed on dynamic MRI has previously been shown to be associated with anterior knee pain. In this MRI study of 60 patients we investigated the relationship between subluxation and multiple bony, cartilaginous and soft-tissue factors that might predispose to subluxation using discriminant function analysis. Patella engagement (% of patella cartilage overlapping with trochlea cartilage) had the strongest relationship with subluxation. Patellae with > 30% engagement tended not to sublux; those with < 30% tended to sublux. Other factors that were associated with subluxation included the tibial tubercle-trochlea notch distance, vastus medialis obliquus distance from patella, patella alta, and the bony and cartilaginous sulcus angles in the superior part of the trochlea. No relationship was found between subluxation and sulcus angles for cartilage and bone in the middle and lower part of the trochlea, cartilage thicknesses and Wiberg classification of the patella. This study indicates that patella engagement is a key factor associated with patellar subluxation. This suggests that in patients with anterior knee pain with subluxation, resistant to conservative management, surgery directed towards improving patella engagement should be considered. A clinical trial is necessary to test this hypothesis.

The patho-anatomy of patellofemoral subluxation.

We scanned 25 left knees in healthy human subjects
using MRI. Multiplanar reconstruction software was used to take
measurements of the inferior and posterior facets of the femoral
condyles and the trochlea. A â€˜basic circleâ€™ can be defined which, in the sagittal plane,
fits the posterior and inferior facets of the lateral condyle, the
posterior facet of the medial condyle and the floor of the groove
of the trochlea. It also approximately fits both condyles in the
coronal plane (inferior facets) and the axial plane (posterior facets).
The circle fitting the inferior facet of the medial condyle in the
sagittal plane was consistently 35% larger than the other circles
and was termed the â€˜medial inferior circleâ€™. There were strong correlations
between the radii of the circles, the relative positions of the
centres of the condyles, the width of the condyles, the total knee
width and skeletal measurements including height. There was poor
correlation between the radii of the circles and the position of
the trochlea relative to the condyles. In summary, the condyles are approximately spherical except for
the inferior facet medially, which has a larger radius in the sagittal
plane. The size and position of the condyles are consistent and
change with the size of the person. However, the position of the
trochlea is variable even though its radius is similar to that of
the condyles. This information has implications for understanding
anterior knee pain and for the design of knee replacements. Cite this article: Bone Joint J 2014;96-B:1623â€“30.

The shape of the distal femur: a geometrical study using MRI

Background
Osteoarthritis affecting the knee is common and represents a continuum of disease from early cartilage thinning to full‐thickness cartilage loss, bony erosion, and deformity. Many studies do not stratify their results based on the severity of the disease at baseline or recruitment.

Surgical interventions for symptomatic mild to moderate knee osteoarthritis.

Purpose
Isolated symptomatic patellofemoral osteoarthritis has been reported in 2% of men and 8% of women older than the age of 55 years in the community. With the development of improved designs and surgical techniques, interest in the use of patellofemoral replacement has increased. The primary aim of the newer generation of patellofemoral replacement implant designs has been to more closely reproduce normal knee kinematics. This study compares the functional sagittal plane in vivo kinematics of a contemporary patellofemoral prosthesis, the FPV, with normal knee kinematics using the patella tendon angle and patella flexion angle relationships with the knee flexion angle.

A P Monk

Papers

Arthroscopic partial meniscectomy for meniscal tears of the knee: a systematic review and meta-analysis

The patho-anatomy of patellofemoral subluxation.

The shape of the distal femur: a geometrical study using MRI

Surgical interventions for symptomatic mild to moderate knee osteoarthritis.

In vivo sagittal plane kinematics of the FPV patellofemoral replacement