The development, validation and internal consistency of the Norwich Patellar Instability (NPI) score

Recurrent patellar dislocation: personalised therapy or operative treatment? The REPPORT randomised trial protocol

INTRODUCTION

Recurrent patellar dislocation is a debilitating musculoskeletal condition, affecting mainly adolescents and adults under the age of 30. It can persist for many decades, causing pain and cartilage and soft-tissue damage, potentially leading to osteoarthritis. Recurrent patellar dislocation can be managed with physiotherapy or surgery. However, it is not known which treatment is most effective.

METHODS AND ANALYSIS

Recurrent Patellar Dislocation: Personalised Therapy or Operative Treatment (REPPORT) is a pragmatic, multicentre, two-arm, superiority, randomised controlled trial. It will compare the clinical and cost-effectiveness of an initial management strategy of personalised, phased and progressive rehabilitation, termed personalised knee therapy versus surgery for recurrent patellar dislocation.The trial's target sample size is 276 participants who will be recruited from approximately 20 sites across the UK. Participants will be randomly allocated to the two treatment groups via a central computer-based minimisation system. Treatment allocation will be in a 1:1 ratio, stratified by age, presence of patella alta and recruitment site.The primary outcome is participant-reported function using the Knee injury and Osteoarthritis Outcome 4-domain score at 18 months post randomisation. Health economic evaluation will be conducted from a healthcare system and personal social services perspective. Secondary outcome data including patellar instability, health utility, work/education status, satisfaction with social roles and treatment, health resource use and adverse events will be collected at 6, 12, 18 and 24 months. Analysis will be on an intention-to-treat basis and reported in-line with the Consolidated Standards of Reporting Trials statement.

ETHICS AND DISSEMINATION

The trial was approved by the East Midlands-Nottingham 2 Research Ethics Committee on 30 March 2023.Results will be disseminated via peer-reviewed publications, presentations at national and international conferences, in lay summaries, and using the REPPORT website and social media channels.

TRIAL REGISTRATION NUMBER

ISRCTN17972668.

Clinical value of questionnaires & physical tests for patellofemoral pain: Validity, reliability and predictive capacity

OBJECTIVES

To determine the most appropriate method of functional assessment for "patellofemoral pain" (PFP)/"chondromalacia patella" for its diagnostic value, (validity, reliability, sensitivity, specificity, predictive value and clinical applicability); to outline initial interpretations of the questionnaires and their appropriateness, through the cut-off points determined in their scores based on physical test and Magnetic Resonance Imaging (MRI); to establish which methods should be used in conjunction with each other to obtain clinical diagnoses that are robust effective and efficient.

METHODS

(1)Intra- and inter-observer reliability and of the relationship among PFP questionnaires/physical tests validated. (2)Predictive capacity of the questionnaires. Subject: 113 knees with PFP, assessed using "Knee-injury-and-Osteoarthritis Outcome-Score-for-Patellofemoral-pain-and-osteoarthritis" (KOOS-PF), "Kujala-Patellofemoral-Score" (KPS), "Victorian-Institute-of-Sports-Assessment-for-Patellar-tendons-questionnaire" (VISA-P), and the physical tests: "patellar-palpation", "patellar-tilt", "patellar-apprehension", "Clarke" and "squat".

RESULTS

Questionnaires correlations themselves was 0.78

CONCLUSIONS

KOOS-PF, KPS and VISA-P demonstrated their diagnostic value in PFP/chondromalacia (validity, reliability, sensitivity, specificity, predictive value and clinical applicability). KOOS-PF was the most versatile, and the most appropriate in mild cases and for early detection and prevention. Squat was the best due to its reliability and clinical relationship with the questionnaires, which predicted it correctly. The functional assessment tools discussed should be applied by combining them with each other.

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MESH Headings

• Humans
• Patellofemoral Pain Syndrome
• Reproducibility of Results
• Cartilage Diseases
• Osteoarthritis
• Surveys and Questionnaires
• Patellofemoral Joint

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Affiliation(s)

Gema Chamorro-Moriana Department of Physiotherapy, Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Seville, Spain Research Group “Area of Physiotherapy CTS305”, Spain
Fernando Espuny-Ruiz Department of Physiotherapy, Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Seville, Spain
Carmen Ridao-Fernández Department of Physiotherapy, Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Seville, Spain Research Group “Area of Physiotherapy CTS305”, Spain
Eleonora Magni Department of Nursing, Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Seville, Spain

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Translation, reliability and validity of the Turkish versions of Norwich Patellar Instability score and The Banff Patellar Instability Instrument 2.0

BACKGROUND

Current treatment options for patellofemoral (PF) instability have required functional scoring systems. The Banff Patellar Instability Instrument (BPII) 2.0 and Norwich Patellar Instability (NPI) scores were explicitly created to meet the need to evaluate PF instability. Different patient-reported outcome measurements (PROMs) are used to evaluate anterior knee problems.

OBJECTIVES

To test the validity and reliability of the Turkish version of the BPII 2.0 and NPI score.

STUDY DESIGN AND METHODS

Fifty-one patients that operated for PF instability, older than eighteen years old, were included in this study. Turkish translation of the BPII 2.0 and NPI scores was undertaken through translation into Turkish by an independent translator. Two tests were repeated seven days apart. Intraclass correlation coefficient (ICC) was used for test-retest reliability. Internal consistency was analyzed using Cronbach's alpha. Validity was assessed by correlating the Kujala and Lysholm knee scores.

RESULTS

Fifty-one patients (34 females/17 males), the average age was 25 ± 7, were included in this study. Cronbach's alpha value was 0.829 for BPII 2.0 and 0.843 for NPI for the first time answered by patients. ICC values applied to evaluate test-retest reliability were 0.904 (p < 0.05) for BPII 2.0 and 0.915 (p < 0.05) for NPI. There was a moderate correlation between the BPII 2.0 Turkish version and the Kujala score. There was a very high correlation between the Turkish version of the BPII 2.0 and Lysholm knee scores. An excellent negative correlation was found between Norwich and Kujala scores (r = -0.819, p < 0.05). The correlation coefficient between Norwich and Lysholm scores was -0.662, indicating a high negative correlation (p < 0.05). The correlation coefficients between the Turkish version of BPII 2.0 and NPI were -0.533 (p < 0.05).

CONCLUSIONS

The Turkish version of the BPII 2.0 and NPI score is a reliable and valid instrument for Turkish-speaking patients with patellofemoral instability.

Sulcus-Deepening Trochleoplasty for High-Grade Trochlear Dysplasia: Demystifying the Procedure-a Review of the Current Literature

PURPOSE OF REVIEW

The most common and biomechanically influential pathoanatomic risk factor for recurrent patellofemoral instability is trochlear dysplasia. Sulcus-deepening trochleoplasty is a procedure developed to address high-grade trochlear dysplasia in the setting of patellofemoral instability. The purpose of this paper is to outline the current classification and surgical management of trochlear dysplasia as well as to review the current literature on the clinical outcomes and complications of sulcus-deepening trochleoplasty.

RECENT FINDINGS

This review outlines the most recent literature reporting evidence behind the decision-making to perform a trochleoplasty in the setting of patellofemoral instability and high-grade trochlear dysplasia. Critical parameters include grade of trochlear dysplasia, severity of symptoms, pertinent physical examination findings, surgical techniques, modifications for skeletally immature patients, and considerations for the revision setting. Historic studies have elicited concerns regarding high reported complication rates for trochleoplasty; however, recent studies consistently report good clinical outcomes and acceptable complication rates, similar to those of other patellar stabilizing procedures. The addition of a trochleoplasty in patients with high-grade dysplasia results in a lower re-dislocation rate, significant improvements in patient-reported outcome measures (PROMs) as well as high levels of patient satisfaction and return to sport. The use of sulcus-deepening trochleoplasty for the treatment of high-grade dysplasia and recurrent patellofemoral instability is a well-established technique with good outcomes and an acceptable complication profile. In patients with high-grade dysplasia, trochleoplasty results in lower re-dislocation rates, high patient satisfaction scores, and good clinical and functional outcomes. An understanding of trochleoplasty and its indications should be in the armamentarium of surgeons treating patellofemoral instability.

Adaptation of the Banff Patellofemoral Instability Instrument (BPII) 2.0 into Swedish

BACKGROUND AND PURPOSE

The Banff Patellofemoral Instability Instrument (BPII) 2.0 is a patient-reported outcome measure (PROM) designed specifically for patellofemoral instability. We translated and adapted the BPII 2.0 into Swedish and assessed its psychometric properties.

PATIENTS AND METHODS

The BPII 2.0 was forward- and back-translated. Children aged 10-16 years with patellar dislocation and instability or recurrent dislocation were recruited. Children completed the Swedish BPII 2.0 and KOOS-Child during their initial visit (t0) and 1 week later (t1). Internal consistency and test-retest reliability were evaluated using intraclass correlation coefficients (ICCs) for the BPII 2.0 and KOOS-Child scores comparison. Pearson correlation coefficients examined concurrent validity of the Swedish BPII 2.0 subscales with KOOS-Child subscales.

RESULTS

64 children (46 females), mean age 13.8 (10.0-16.3) years, participated. Time after patellar dislocation or surgery was 3-24 months. 55 patients (86%) returned the second BPII 2.0 and KOOS-Child after an average of 9 (5-22) days. There were no ceiling or floor effects for the total score of the new Swedish BPII 2.0 or for its subscales. BPII 2.0 demonstrated excellent internal consistency at t0 (ICC 0.96, 95% confidence interval [CI] 0.95-0.97) and at t1 (ICC 0.97, CI 0.95-0.98), as well as excellent test-retest reliability (ICC 0.97, CI 0.96-0.98). Concurrent validity of the BPII 2.0 subscales with KOOS-Child subscales was moderate to strong (rho 0.40-0.88).

CONCLUSION

The Swedish BPII 2.0 showed excellent internal consistency as well as excellent test-retest reliability and is a reliable and valid questionnaire.

Feasibility of return to sports assessment 6 months after patellar instability surgery

BACKGROUND

The evidence regarding the usefulness of assessment tools to support decisions of return-to-sport after surgery for patellar instability is scarce. The purpose of this study was therefore to explore the feasibility of functional tests assessing readiness for return-to-sport six months after patellar stabilizing surgery. However, there is little evidence on what a functional assessment should include to support these decisions following surgery for patellar instability. Therefore the purpose of this study was to explore the feasibility of functional tests assessing readiness for return-to-sport six months after patellar stabilizing surgery.

METHODS

In this cross-sectional study a prospective cohort of 78 patients were subjected to a range of return-to-sport readiness tests at six months after surgery for patellar instability with an "a la carte" approach. Lower Quarter Y-Balance Test (YBT-LQ), single-legged hop tests and isokinetic strength tests were performed. In addition, self-reported function was measured with the Banff Patellofemoral Instability Instrument 2.0 (BPII) and Norwich Patellar Instability score (NPI). Return-to-sport clearance criteria were defined as: ≤4 cm YBT-LQ anterior reach difference between legs, leg-symmetry-index (LSI) ≥ 95% in the YBT-LQ composite score, mean sum score LSI ≥ 85% of all single-leg hop tests and LSI ≥ 90% in isokinetic quadriceps strength.

RESULTS

Sixty-four patients (82%) were able to complete all functional tests, while only eleven (14%) patients were deemed ready for return-to-sport, passing all return-to-sport clearance criteria. Patients with bilateral problems demonstrated worse performance in the contralateral leg, which resulted in higher LSI scores compared to individuals with unilateral instability. A supplementary finding was that the extent of surgery (MPFL-R only versus combined surgery) did not predict and mainly did not affect self-reported function or functional performance at the follow-up.

CONCLUSION

The functional assessment used in the current study seems feasible to conduct at six months after patellar stabilizing surgery. However, current suggested clearance standards and the use of leg-symmetry-index seems inappropriate for patients with patellar instability. Therefore, further exploration of appropriate tests and return-to-sport clearance criteria is justified.

TRIAL REGISTRATION

clinicaltrial.gov, NCT05119088. Registered 12.11.2021 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05119088 .

Patient-reported outcome measures for patellofemoral disorders: a systematic review

INTRODUCTION

Patellofemoral conditions include, but are not limited to, anterior knee pain syndrome and patellar instability. Patients and surgeons may find it difficult to identify the specific source of the symptoms and clinical scenarios, so patient-reported outcome measures (PROMs) may be a useful diagnostic aid. There are a number of available PROMs for patellofemoral conditions, which are often used indistinctly. This systematic review explores the available PROMs for patellofemoral conditions, their use and methodological quality.

METHODS

A systematic review was conducted, searching for scientific articles relating to PROMs in patellofemoral conditions, from inception to July 2022. Scoring systems including physician-directed or imagining assessment were not included. All types of conditions in the patellofemoral joint were considered.

RESULTS

Twenty-two relevant PROMs were encountered, divided into four categories: eight PROMs for anterior knee pain syndrome, five for patellar instability, four for other patellofemoral conditions and five for non-specific PROMs.

CONCLUSIONS

While many PROMs have been found used in patellofemoral research, only few of them have showed sufficient methodological quality. In addition, PROMs employed in PF literature are often inaccurately chosen. This review may help authors to better understand the characteristics of specific patellofemoral PROMs, in order to select the more appropriate and recommended ones.

LEVEL OF EVIDENCE

Level II.

Patients' experiences of living with patellar instability before and after surgery: a qualitative interview study

OBJECTIVES

To explore the experience of living with patellar instability before and after surgery.

DESIGN

Qualitative individual semistructured interviews of patients with patellar instability using a four-step thematic cross-case analysis strategy (systematic text condensation).

SETTING

Two orthopaedic units within two large Hospitals in Norway.

PARTICIPANTS

A convenience sample of 15 participants, aged between 16 and 32 years, who had undergone surgery for patellar instability within the last 6-12 months.

RESULTS

Participants offered rich and detailed descriptions of the impact and lived experience of patellar instability, including fear of new dislocations, increased awareness of the knee and adaptations to avoidance behaviour in everyday life both before and after surgery. The four major themes that emerged from the data were: (1) fear of patella dislocations governs everyday life activities, (2) adaptation to avoidance behaviour, (3) feeling different, misunderstood and stigmatised affects self-esteem and (4) feeling stronger, but still not fully confident in the knee after surgery.

CONCLUSIONS

These findings offer insight into the experience of living with patellar instability. Patients reported that the instability had major impacts on their everyday life, affecting ability to participate in social life and physical activities both before and after surgery. This may imply that an increased attention towards cognitive interventions may be useful in the management of patellar instability.

TRIAL REGISTRATION NUMBER

NCT05119088.

Cross-cultural Validation of the Norwegian Version of the Banff Patellofemoral Instability Instrument 2.0

Background

The Banff Patellofemoral Instability Instrument (BPII) 2.0 is a disease-specific quality of life questionnaire for patients with patellofemoral instability. While good psychometric properties have been demonstrated, the data lack cross-cultural validity, construct validity, and an established measurement error.

Purpose

To (1) translate and cross-culturally adapt the BPII 2.0 to the Norwegian version (BPII 2.0-No) and (2) examine the psychometric properties of the Norwegian version.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

The BPII 2.0 was translated according to international guidelines. A cohort of 100 patients surgically treated for recurrent patellofemoral instability completed the BPII 2.0-No, related outcome measures (Norwich Patellar Instability Score, International Knee Documentation Committee Subjective Knee Form 2000, Knee injury and Osteoarthritis Outcome Score, and Tampa Scale of Kinesiophobia), and functional tests (Y-Balance Test-Lower Quarter, single-leg hop tests, and knee extension strength) before and/or 6 months after surgery. We evaluated the face and content validity, internal consistency (Cronbach α), test-retest reliability (intraclass correlation coefficient [ICC]), measurement error (SEM and smallest detectable change at the individual [SDCind] and group levels [SDCgroup]). Construct validity was assessed by testing 9 hypotheses on the correlation between the BPII 2.0-No and the outcome measures/functional tests (Pearson r).

Results

The BPII 2.0-No had good face and content validity. Internal consistency was excellent (α = .95), and no floor or ceiling effects were found. Test-retest reliability was high (ICC2,1 = 0.87; 95% CI, 0.77-0.93), and measurement error was low (SEM = 7.1). The SDCind was 19.7 points and the SDCgroup was 2.8 points. Eight of the 9 hypotheses regarding construct validity were confirmed.

Conclusion

The BPII 2.0-No was found to be valid and reliable. This study adds further knowledge on the measurement properties of the BPII 2.0 that can be used internationally.

Surgical versus non-surgical interventions for treating patellar dislocation

BACKGROUND

Patellar (knee cap) dislocation occurs when the patella disengages completely from the trochlear (femoral) groove. It affects up to 42/100,000 people, and is most prevalent in those aged 20 to 30 years old. It is uncertain whether surgical or non-surgical treatment is the best approach. This is important as recurrent dislocation occurs in up to 40% of people who experience a first time (primary) dislocation. This can reduce quality of life and as a result people have to modify their lifestyle. This review is needed to determine whether surgical or non-surgical treatment should be offered to people after patellar dislocation.

OBJECTIVES

To assess the effects (benefits and harms) of surgical versus non-surgical interventions for treating people with primary or recurrent patellar dislocation.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, AMED, CINAHL, Physiotherapy Evidence Database and trial registries in December 2021. We contacted corresponding authors to identify additional studies.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled clinical trials evaluating surgical versus non-surgical interventions for treating primary or recurrent lateral patellar dislocation in adults or children.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent patellar dislocation, and patient-rated knee and physical function scores. Our secondary outcomes were health-related quality of life, return to former activities, knee pain during activity or at rest, adverse events, patient-reported satisfaction, patient-reported knee instability symptoms and subsequent requirement for knee surgery. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included 10 studies (eight randomised controlled trials (RCTs) and two quasi-RCTs) of 519 participants with patellar dislocation. The mean ages in the individual studies ranged from 13.0 to 27.2 years. Four studies included children, mainly adolescents, as well as adults; two only recruited children. Study follow-up ranged from one to 14 years. We are unsure of the evidence for all outcomes in this review because we judged the certainty of the evidence to be very low. We downgraded each outcome by three levels. Reasons included imprecision (when fewer than 100 events were reported or the confidence interval (CI) indicated appreciable benefits as well as harms), risk of bias (when studies were at high risk of performance, detection and attrition bias), and inconsistency (in the event that pooled analysis included high levels of statistical heterogeneity). We are uncertain whether surgery lowers the risk of recurrent dislocation following primary patellar dislocation compared with non-surgical management at two to nine year follow-up. Based on an illustrative risk of recurrent dislocation in 348 people per 1000 in the non-surgical group, we found that 157 fewer people per 1000 (95% CI 209 fewer to 87 fewer) had recurrent dislocation between two and nine years after surgery (8 studies, 438 participants). We are uncertain whether surgery improves patient-rated knee and function scores. Studies measured this outcome using different scales (the Tegner activity scale, Knee Injury and Osteoarthritis Outcome Score, Lysholm, Kujala Patellofemoral Disorders score and Hughston visual analogue scale). The most frequently reported score was the Kujala Patellofemoral Disorders score. This indicated people in the surgical group had a mean score of 5.73 points higher at two to nine year follow-up (95% CI 2.91 lower to 14.37 higher; 7 studies, 401 participants). On this 100-point scale, higher scores indicate better function, and a change score of 10 points is considered to be clinically meaningful; therefore, this CI includes a possible meaningful improvement. We are uncertain whether surgery increases the risk of adverse events. Based on an assumed risk of overall incidence of complications during the first two years in 277 people out of 1000 in the non-surgical group, 335 more people per 1000 (95% CI 75 fewer to 723 more) had an adverse event in the surgery group (2 studies, 144 participants). Three studies (176 participants) assessed participant satisfaction at two to nine year follow-up, reporting little difference between groups. Based on an assumed risk of 763 per 1000 non-surgical participants reporting excellent or good outcomes, seven more participants per 1000 (95% CI 199 fewer to 237 more) reported excellent or good satisfaction. Four studies (256 participants) assessed recurrent patellar subluxation at two to nine year follow-up. Based on an assumed risk of patellar subluxation in 292 out of 1000 in the non-surgical group, 73 fewer people per 1000 (95% CI 146 fewer to 35 more) had patellar subluxation as a result of surgery. Slightly more people had subsequent surgery in the non-surgical group. Pooled two to nine year follow-up data from three trials (195 participants) indicated that, based on an assumed risk of subsequent surgery in 215 people per 1000 in the non-surgical group, 118 fewer people per 1000 (95% CI 200 fewer to 372 more) had subsequent surgery after primary surgery.

AUTHORS' CONCLUSIONS

We are uncertain whether surgery improves outcome compared to non-surgical management as the certainty of the evidence was very low. No sufficiently powered trial has examined people with recurrent patellar dislocation. Adequately powered, multicentre, randomised trials are needed. To inform the design and conduct of these trials, expert consensus should be achieved on the minimal description of both surgical and non-surgical interventions, and the pathological variations that may be relevant to both choice of these interventions.

Patient-Reported Outcomes Following Medial Patellofemoral Reconstruction With Peroneus Longus Allografts Demonstrate Good Results

Purpose

To evaluate the recurrent dislocation risk and patient-reported outcomes of peroneus longus allograft tissue for medial patellofemoral ligament (MPFL) reconstruction.

Methods

Patients who underwent MPFL reconstruction with peroneus longus allograft at an academic center between 2008 and 2016 were identified. Record review and patient contact were used to identify any cases of recurrent patellar dislocation and collect patient-reported outcomes scores (Knee injury and Osteoarthritis Outcome Score [KOOS], Norwich Patellar Instability score, Marx activity scale). Patients with 1-year minimum follow-up were included. Outcomes were quantified and the proportion of patients reaching a previously defined patient acceptable symptom state (PASS) for patellar instability was determined.

Results

Sixty-one patients (42 female and 19 male) underwent MPFL reconstruction with peroneus longus allograft during the study period. Forty-six patients (76%) with 1-year minimum follow up were contacted at a mean of 3.5 years postoperative. The mean age at time of surgery was 22 ± 7.2 years. Patient-reported outcomes data were available in 34 patients. Mean KOOS subscale scores were as follows: Symptoms 83.2 ± 19.1, Pain 85.2 ± 17.6, Activities of Daily Living 89.9 ± 14.8, Sports 75 ± 26.2, and Quality of Life 72.6 ± 25.7. The mean Norwich Patellar Instability score was 14.9% ± 17.4%. The mean Marx activity score was 6.0 ± 5.2. No recurrent dislocations were noted during the study period. Sixty-three percent of patients who underwent isolated MPFL reconstruction met PASS thresholds in at least 4 of 5 KOOS subscales.

Conclusions

The use of a peroneus longus allograft in MPFL reconstruction in conjunction with other indicated procedures results in a low re-dislocation risk and a high proportion of patients meeting PASS criteria for patient-reported outcome scores 3 to 4 years postoperatively.

Level of Evidence

IV, case series.

Patellofemoral articular cartilage damage is associated with poorer patient-reported outcomes following isolated medial patellofemoral ligament reconstruction

PURPOSE

The purpose of this study was to investigate the impact of articular cartilage damage on outcomes following medial patellofemoral ligament (MPFL) reconstruction.

METHODS

Record review identified 160 patients who underwent isolated MPFL reconstruction at a single institution between 2008 and 2016. Patient demographics, patellofemoral articular cartilage status at surgery, and patient anatomical measures from imaging were obtained via chart review. Patients were contacted and outcomes assessed through collection of Norwich Patellar Instability (NPI) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Marx activity score as well as an assessment for recurrent patellar dislocation. Outcomes of patients with grade 0-II patellofemoral cartilage damage were compared to those of patients with grade III-IV cartilage damage.

RESULTS

One hundred twenty-two patients (76%) with a minimum of one year follow-up were contacted at a mean of 4.8 years post-operatively. A total of 63 patients (52%) had grade III or IV patellofemoral chondral damage at the time of surgery. The majority of the defects was on the medial patella (46 patients-72%) and the mean patellar defect size was 2.8 cm². Among 93 patients who completed patient-reported outcome scores, the 52 with grade III or IV chondral damage reported a significantly poorer KOOS Quality of Life than the 44 patients with grade 0 to II chondral damage (p = 0.041), controlling for patient age, sex, BMI, and anatomical factors.

CONCLUSION

Patients with grade III or IV articular cartilage damage of the patellofemoral joint at the time of MPFL reconstruction demonstrated poorer KOOS knee-related quality of life than patients without grade III or IV articular cartilage damage at a mean of 4.8 years following isolated MPFL reconstruction.

LEVEL OF EVIDENCE

Level II.

Accelerated rehabilitation program following medial patellofemoral ligament reconstruction does not increase risk of recurrent instability

BACKGROUND

Rehabilitation protocols following medial patellofemoral ligament (MPFL) reconstruction were historically restrictive, with patients often immobilized and/or given weightbearing restrictions. However, more recently published protocols have been more aggressive. We compared patient-reported outcomes and recurrent dislocation risk between patients treated with a restrictive rehabilitation program (early post-operative bracing and weightbearing restrictions) and an accelerated rehabilitation protocol (no post-operative bracing or weightbearing restrictions) following MPFL reconstruction.

METHODS

Patients who underwent isolated MPFL reconstruction at an academic center between 2008 and 2016 were identified. Patient demographics, anatomical measurements, surgical details, and outcomes were collected. During this period, the rehabilitation protocol at the center transitioned from a restrictive to an accelerated rehabilitation protocol. Failure risk and patient-reported outcomes were compared based on rehabilitation protocol.

RESULTS

Of the163 isolated MPFL reconstructions performed during the study period, 123 (75%) were available for minimum one-year follow up at a mean of 4.0 years post-operative. Overall, 53 knees (43%) underwent the accelerated rehabilitation protocol and the remaining 70 knees (57%) underwent the restrictive protocol. There were 3 recurrent dislocations during the study period (2.4%), all of which occurred in the restrictive rehabilitation group. Multiple linear regression demonstrated that being in the accelerated rehabilitation group was not associated with poorer Knee injury and Osteoarthritis Outcome Score (KOOS) subscales controlling for age, sex, body mass index, Caton-Deschamps Index, tibial tubercle-trochlear groove distance, sulcus angle, MPFL graft choice, and length of follow-up.

CONCLUSION

An accelerated rehabilitation protocol without immobilization or weightbearing restrictions does not increase risk of recurrent patellar dislocation or poorer patient-reported outcome following isolated MPFL reconstruction.

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).

Editorial Commentary: A Complex Network of Bony and Soft-Tissue Stabilizers-and Overall Limb Alignment-Determines Patellofemoral Stability

Patellofemoral stability is maintained through a complex network of static and dynamic soft-tissue stabilizers, the osseous structure of the patella and trochlea, and overall limb alignment. Thus, determining the risk of recurrent patellar instability must account for as many of these factors as possible in the clinical decision-making process. The tibial tubercle-trochlear groove distance is the most common parameter used for this evaluation but may be limited because of methodologic issues and because this distance is an absolute value. Indices that incorporate other predisposing factors, including trochlear dysplasia, increase the accuracy of predicting recurrent patellar instability and can be used to generate a patient-specific treatment plan.

The Tibial Tubercle-Trochlear Groove Distance/Trochlear Dysplasia Index Quotient Is the Most Accurate Indicator for Determining Patellofemoral Instability Risk

PURPOSE

The primary aim of our study was to evaluate diagnostic accuracy of the tibial tubercle-trochlear groove (TT-TG) distance relative to associated quotients produced from trochlear width (TT-TG distance/TW) and trochlear dysplasia index (TT-TG distance/TDI) for detecting patellofemoral instability. Secondary aims included identifying thresholds for risk and comparing differences between cases and controls.

METHODS

Consecutive sampling of electronic medical records produced 48 (21 males, 27 females) patellofemoral instability cases (19 ± 7 years old) and 79 (61 males, 18 females) controls (23 ± 4 years old) who had a history of isolated meniscal lesion, as evaluated by magnetic resonance imaging. Standardized methods were employed with measurements executed in a blinded and randomized manner. A receiver operating characteristic curve assessed accuracy by area under the curve (AUC). The index of union (IU) was employed to identify a threshold for risk. Two-sample t-tests examined group differences. P < .05 denoted statistical significance.

RESULTS

The AUC values were .69 (.60, .79) for TT-TG distance, .81 (.73, .88) for TT-TG distance/TW, and .85 (.78, .91) for TT-TG distance/TDI. Thresholds were 14.7 mm for TT-TG distance, .36 for TT-TG distance/TW, and 1.88 for TT-TG distance/TDI. Cases demonstrated statistically significant (P < .001) greater values for each measure compared with controls: TT-TG distance (15.8 ± 4.2 mm vs 12.9 ± 3.6 mm, [1.4, 4.3]); TT-TG distance/TW (.51 ± .24 vs .31 ± .09, [.13, .27]); TT-TG distance/TDI (3.07 ± 1.55 vs 1.7 ± .7, [.9, 1.84]).

CONCLUSION

The TT-TG distance, TT-TG distance/TW, and TT-TG distance/TDI measures were 69%, 81%, and 85%, respectively, accurate for determining patellofemoral instability risk. Thresholds for risk were 14.7 mm for TT-TG distance, .36 for TT-TG distance/TW, and 1.88 for TT-TG distance/TDI. The thresholds reported in this study may help in advancing clinical decision-making.

LEVEL OF EVIDENCE

Level III, diagnostic retrospective comparative observatory trial.

Comparable outcome for autografts and allografts in primary medial patellofemoral ligament reconstruction for patellofemoral instability: systematic review and meta-analysis

PURPOSE

This study updates the current evidence on the role of allografts versus autografts for medial patellofemoral ligament (MPFL) reconstruction in patients with patellofemoral instability.

METHODS

The study was performed according to the PRISMA guidelines. In March 2021, a literature search in the main online databases was performed. Studies reporting quantitative data concerning primary MPFL reconstruction using an allograft were considered for inclusion. The Coleman Methodology Score was used to assess the methodological quality of the selected articles.

RESULTS

Data from 12 studies (474 procedures) were retrieved. The mean follow-up was 42.2 (15-78.5) months. The mean age was 21.1 ± 6.2 years. 64.9% (285 of 439) of patients were female. At the last follow-up, the Tegner (p < 0.0001), Kujala (p = 0.002) and the Lysholm (p < 0.0001) scores were minimally greater in the autografts. The similarity was found in the rate of persistent instability sensation and revision. The allograft group evidenced a lower rate of re-dislocations (p = 0.003).

CONCLUSION

Allografts may represent a feasible alternative to traditional autograft for MPFL reconstruction in selected patients with patellofemoral instability. Allograft tendons yielded similar PROMs, rates of persistent instability, and revision. Allograft reconstructions tended to have modestly lower re-dislocation rates.

LEVEL OF EVIDENCE

IV.

Patient-reported outcome scores following patellar instability surgery-high prevalence does not equal high responsiveness: a systematic review

PURPOSE

The purpose of this study was to determine the utilization and responsiveness of common patient-reported outcomes (PROs) in patients undergoing surgery for patellar instability.

METHODS

Using PRISMA guidelines, a systematic review of studies reporting outcomes following surgical intervention for patellar instability was conducted using Pubmed, Cochrane, OVID Medline, and Google Scholar. Subgroup analysis of articles reporting at least two PROs with baseline and follow-up data were used to evaluate responsiveness of instruments using relative efficiency and effect size.

RESULTS

From the search, 2,848 unique articles were found, of which 178 were included in final analysis (7,122 patients, mean age 22.6, 63.6% female). The most commonly used PRO was the Kujala score (79.2%), followed by the Lysholm (34.8%), and Tegner (30.9%). Seventy-nine articles were eligible for subgroup analysis. The Kujala had a higher relative efficiency than ten of the 14 instruments to which it was compared but had lower relative efficiency compared to the IKDC and Lysholm scores. The Banff Patella Instability Instrument (BPII) and the Norwich score, condition-specific tools, were unable to be fully assessed due to rarity of use and lack of comparisons.

CONCLUSION

The hypothesis that the Kujala score is the most commonly used PRO for patellar instability, although other instruments offer greater efficiency was supported by our results. The IKDC and Lysholm scores had similar effect sizes but higher relative efficiencies than the Kujala, thus suggesting better responsiveness. This analysis adds useful information for surgeons on the effectiveness of the most common PRO's for evaluating patellofemoral instability outcomes.

LEVEL OF EVIDENCE

Level III.

Portuguese Translation and Cross-Cultural Adaption of the Banff Patella Instability Instrument

Objective  To translate into Brazilian Portuguese and to cross-culturally adapt the Banff Questionnaire for Patellar Instability. Methods  The translation and cross-cultural adaptation followed the linguistic validation process proposed by international guidelines, which consists of six steps: translation, synthesis, back-translation, review by an expert committee, pretest, and final report presentation to the authors of the original questionnaire. Literate patients with recurrent patellar instability, older than 12 years of age, who signed the informed consent form or had it signed by a legal guardian were included in the study. Patients with neurological or systemic comorbidities were excluded from the study. Results  A total of 62 patients (18 males and 44 females) were included in the study. Discrepancies observed during the processes of translation and harmonization of the back-translations were modified with no need for reformulation. No pretest version replacements were required. Conclusion  The Banff Questionnaire for Patellar Instability has been successfully translated and cross-culturally adapted into Brazilian Portuguese, so it can be used to assess patients with patellar instability who speak this language.

Assessing knee functionality: systematic review of validated outcome measures

BACKGROUND

Functional rating scales allow clinicians to document and quantify alterations and progression of recovery processes. There is neither awareness of numerous knee scales nor are they easy to find or compare to select the most suitable.

OBJECTIVES

We aimed to compile validated knee functional rating tools and analyse the methodological quality of their validation studies. Also, we aimed to provide an operational document of the outcome measures addressing descriptions of parameters, implementations, instructions, interpretations and languages, to identify the most appropriate for future interventions.

METHODS

A systematic review involved a search of PubMed, Web of Science, CINAHL, Scopus, and Dialnet databases from inception through September 2020. The main inclusion criteria were available functional rating scales/questionnaires/indexes for knees and validation studies. Methodological quality was analyzed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) and COnsensus-based Standards for the selection of health Measurement Instruments Risk of Bias (COSMIN-RB).

RESULTS

We selected 73 studies. The studies investigated 41 knee rating tools (general, 46%, and specific, 54%) and 71 validations, including 29,742 individuals with knee disorders. QUADAS-2 obtained the best results in patient selection and index test (applicability section). COSMIN-RB showed the highest quality in construct validity (most analyzed metric property). The specific tools were mainly designed for prosthesis and patellofemoral and anterior cruciate ligament injuries. More considered issues were specific function (93%), especially gait, pain/sensitivity (81%), and physical activity/sports (56%).

CONCLUSIONS AND IMPLICATIONS

We conducted a necessary, useful, unlimited-by-time and feasible compilation of validated tools for assessing knee functional recovery. The methodological quality of the validations was limited. The best validations were for the Copenhagen Knee Range of Motion Scale in osteoarthritis and arthroplasties, Knee Outcome Survey Activities of Daily Living and Lysholm Knee Score for general knee disorders and the Tegner Activity Score for anterior cruciate ligament injuries. The operational document for the scales provides necessary data to identify the most appropriate.

Is an individually tailored programme of intense leg resistance and dynamic exercise acceptable to adults with an acute lateral patellar dislocation? A feasibility study

Background

Lateral patellar dislocations mainly affect active teenagers and young adults. To help people recover, non-surgical exercise-based treatment is often recommended but the optimal exercise-based treatment is unknown. Currently, treatment outcomes after this injury are variable. Common problems include recurrent dislocation, reduced activity levels, and later surgery. A programme of intense leg resistance exercises, and dynamic exercises related to participants’ activity-related goals, has rationale, but has not been previously reported. In line with the Medical Research Council guidance, this study aimed to assess the acceptability of a novel evidence-based exercise programme for adults after acute lateral patellar dislocation and the feasibility of future research evaluating this treatment.

Methods

A single-group prospective study was conducted at the John Radcliffe Hospital, Oxford, UK. Participants were 16 years or older with an acute first-time or recurrent lateral patellar dislocation. Participants received up to six face-to-face, one-to-one, physiotherapy sessions, over a maximum of 3 months, and performed intensive home exercises independently at least three times per week. Strategies to increase exercise adherence were used. Primary objectives were to determine the number of eligible patients, the recruitment rate (proportion of eligible patients that provided written informed consent), participant adherence to scheduled physiotherapy sessions and self-reported adherence to prescribed exercise, and intervention acceptability to participants measured by attrition and a study-specific questionnaire. Data were analysed using descriptive statistics.

Results

Fifteen of 22 (68%) patients with a lateral patellar dislocation were eligible. All eligible (100%) were recruited. Two of 15 (13%) participants provided no outcome data, 2/15 (13%) provided partial outcome data, and 11/15 (73%) provided all outcome data. Questionnaire responses demonstrated high intervention acceptability to participants. Participants attended 56/66 (85%) physiotherapy sessions and 10/11 (91%) participants reported they ‘always’ or ‘often’ completed the prescribed exercise. One participant redislocated their patella; another experienced knee pain or swelling lasting more than one week after home exercise on three occasions.

Conclusion

The intervention appeared acceptable to adults after acute lateral patellar dislocation, and a future randomised pilot trial is feasible. This future pilot trial should estimate attrition with increased precision over a longer duration and assess participants’ willingness to be randomised to different treatments across multiple centres.

Trial registration

ClinicalTrials.govNCT03798483, registered on January 10, 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00932-x.

The Comprehensive Aachen Knee Score: Development and validation of a new patient-reported outcome measure for patellofemoral pathologies

BACKGROUND

Existing patient-reported outcome measures (PROMs) that assess knee pain and symptoms show insufficient quality regarding their psychometric properties. We developed and validated a new PROM assessing knee pain and especially patellofemoral pathologies, the COMPrehensive AaChen Knee Score (COMPACK).

METHODS

We followed a three-phase process of development and validation. (1) Scale development: we conducted a systematic literature research to collect and analyse the most commonly used PROMs for knee and patellofemoral pathologies to identify appropriate items. (2) Pilot testing: we assessed the content validity of the COMPACK based on interviews with patients and health experts regarding relevance, comprehensibility and comprehensiveness of the used items. (3) Field testing: we used the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines to evaluate the structural validity, internal consistency and test-retest reliability of the COMPACK.

RESULTS

The COMPACK scale showed good structural validity, with two subscales measuring pain intensity and frequency. Further, scores of the COMPACK correlated positively with those obtained from the International Knee Documentation Committee Subjective Knee Form (IKDC) (r = 0.64) and the 12-item Short Form Health Survey subscale of physical function: (r = 0.43). Both the total scale and the two subscales showed good internal consistency (Cronbach's α > 0.82) and good to excellent test-retest reliability (Cronbach's α > 0.82).

CONCLUSIONS

The final COMPACK score was shown to be a valid and reliable instrument and thus meets the most important psychometric quality criteria. In its development, we specifically focused on its content validity, structural validity and applicability.

Changes in pain catastrophization and neuropathic pain following operative stabilisation for patellofemoral instability: a prospective study with twelve month follow-up

PURPOSE

To determine the prevalence and change in neuropathic pain or pain catastrophizing before and 12 months following patellar stabilisation surgery for patellofemoral instability.

METHODS

We conducted a prospective clinical audit within a UK NHS orthopaedic surgical centre. Data from 84 patients with patellofemoral instability requiring stabilisation were analysed. Fifty percent (42/84) underwent MPFL reconstruction alone, and 16% (13/84) had both trochleoplasty and MPFL reconstruction. Neuropathic pain was assessed using painDETECT score. Pain catastrophizing was assessed using the Pain Catastrophizing Score. The Norwich Patellar Instability (NPI) Score and Kujala Patellofemoral Disorder Score were also routinely collected pre-operatively and one year post-operatively.

RESULTS

At 12 months post-operatively there was a statistically significant reduction in mean Pain Catastrophizing Scores (18.9-15.7; p < 0.02), but no change in mean painDETECT scores (7.3-7.8; p = 0.72). There was a statistically significant improvement in NPI scores (90.2-61.9; p < 0.01) and Kujala Patellofemoral Disorder Scores (48.7-58.1; p = 0.01). The prevalence of pain catastrophizing decreased from 31% pre-operatively to 24% post-operatively, whereas the prevalence of neuropathic pain remained consisted (10-11%).

CONCLUSIONS

Neuropathic pain and catastrophizing symptoms are not commonly reported and did not significantly change following patellofemoral stabilisation surgery. Whilst low, for those affected, there remains a need to intervene to improve outcomes following PFI surgery.

The feasibility of a randomised control trial to assess physiotherapy against surgery for recurrent patellar instability

Background

Patellar instability is a relatively common condition that leads to disability and restriction of activities. People with recurrent instability may be given the option of physiotherapy or surgery though this is largely driven by clinician preference rather than by a strong evidence base. We sought to determine the feasibility of conducting a definitive trial comparing physiotherapy with surgical treatment for people with recurrent patellar instability.

Methods

This was a pragmatic, open-label, two-arm feasibility randomised control trial (RCT) with an embedded interview component recruiting across three NHS sites comparing surgical treatment to a package of best conservative care; ‘Personalised Knee Therapy’ (PKT). The primary feasibility outcome was the recruitment rate per centre (expected rate 1 to 1.5 participants recruited each month). Secondary outcomes included the rate of follow-up (over 80% expected at 12 months) and a series of participant-reported outcomes taken at 3, 6 and 12 months following randomisation, including the Norwich Patellar Instability Score (NPIS), the Kujala Patellofemoral Disorder Score (KPDS), EuroQol-5D-5L, self-reported global assessment of change, satisfaction at each time point and resources use.

Results

We recruited 19 participants. Of these, 18 participants (95%) were followed-up at 12 months and 1 (5%) withdrew. One centre recruited at just over one case per month, one centre was unable to recruit, and one centre recruited at over one case per month after a change in participant screening approach. Ten participants were allocated into the PKT arm, with nine to the surgical arm. Mean Norwich Patellar Instability Score improved from 40.6 (standard deviation 22.1) to 28.2 (SD 25.4) from baseline to 12 months.

Conclusion

This feasibility trial identified a number of challenges and required a series of changes to ensure adequate recruitment and follow-up. These changes helped achieve a sufficient recruitment and follow-up rate. The revised trial design is feasible to be conducted as a definitive trial to answer this important clinical question for people with chronic patellar instability.

Trial registration

The trial was prospectively registered on the International Standard Randomised Controlled Trial Number registry on the 22/12/2016 (reference number: ISRCTN14950321). http://www.isrctn.com/ISRCTN14950321

Does surgical treatment produce better outcomes than conservative treatment for acute primary patellar dislocations? A meta-analysis of 10 randomized controlled trials

Purpose

The objective of this study was to conduct the latest meta-analysis of randomized controlled trials (RCTs) that compare clinical results between surgery and conservative therapy of acute primary patellar dislocation (APPD), focusing on medial patellofemoral ligament (MPFL) reconstruction.

Methods

We performed a literature search in Embase, The Cochrane Library, PubMed, and Medline to identify RCTs comparing APPD surgical treatment with conservative treatment from the establishment of each database to January 2019. The methodological quality of each RCT was assessed independently by the two authors through the Cochrane Collaboration’s “Risk of Bias” tool. Mean differences of continuous variables and risk ratios of dichotomous variables were computed for the pooled data analyses. The I² statistic and the χ² test were used to evaluate heterogeneity, with the significance level set at I² > 50% or P < 0.10.

Results

Ten RCTs with a sum of 569 patients (297 receiving surgical treatment and 263 receiving conservative treatment) met the inclusion criteria for meta-analysis. Pooled data analysis showed no statistical difference in the field of subluxation rate, Kujala score, patient satisfaction, and frequency of reoperation between the two groups. Tegner activity score and recurrent dislocation rate in the conservative group were significantly higher than those in the surgically treated group.

Conclusions

Conservative treatment may produce better outcomes than surgery for APPD in consideration of Tegner activity score. However, in view of limited research available, the interpretation of the discoveries should be cautious. More convincing evidence is required to confirm the effect of MPFL reconstruction.

Treatment of First-time Patellar Dislocations and Evaluation of Risk Factors for Recurrent Patellar Instability

Approximately one-third of skeletally mature patients with primary patellar dislocation will experience recurrent patellar instability over time. Because of the multifactorial combination of features contributing to overall stability of the patellofemoral joint, first-time patella dislocation presents a challenge to the treating physician. A detailed patient history, focused physical examination, and appropriate diagnostic imaging are essential for identifying risk factors for recurrent instability. Individual risk factors include young patient age, patella alta, trochlear dysplasia, and lateralization of the tibial tubercle. In combination these factors may pose even greater risk, and recently published predictive scoring models offer clinicians objective criteria to identify patients most at risk for recurrence. In patients at low risk of recurrence, nonoperative management can be effective, with "a la carte" surgical treatments gaining popularity in those with a higher than acceptable risk of re-dislocation.

Validity and Reliability of the Banff Patellofemoral Instability Instrument 2.0 in an Adolescent Population

BACKGROUND

Lateral patellofemoral instability is a relatively common problem in the adolescent population. Subjective and objective patient outcomes are commonly used to evaluate treatment success or failure. The Banff Patellofemoral Instability Instrument (BPII) and Paediatric International Knee Documentation Committee (Pedi-IKDC) Subjective Knee Form are patient-reported outcome measures that have been used with an adolescent population previously. The BPII 2.0 is a shortened version of the BPII and has not been validated in an adolescent population. The purpose of the current study was to validate the BPII 2.0 with an adolescent population.

METHODS

This was a multicenter study where patients were recruited from 3 tertiary orthopaedic surgery clinics. A convenience sample (n=140 adolescent patients) with a confirmed diagnosis of lateral patellofemoral instability and who had failed conservative treatment was referred to one of the 3 orthopaedic surgeons. All patients completed the BPII 2.0 and Pedi-IKDC before their clinic appointment. Cronbach's alpha and floor/ceiling effects were used to determine the content validity of both instruments. Patients were also interviewed to ask questions about the BPII 2.0 comprehension and importance of items. One clinic site sent out the BPII 2.0 to 30 additional patients twice in 2 weeks to measure the test-retest reliability (intraclass correlation coefficient 2,k). A Pearson r correlation coefficient was used to determine the relationship between the BPII 2.0 and the Pedi-IKDC and criterion validity.

RESULTS

Cronbach's alpha values were 0.95 and 0.76 for the BPII 2.0 and Pedi-IKDC, respectively. There was no evidence of floor or ceiling effects for either the BPII 2.0 or the Pedi-IKDC. The Pearson r correlation coefficient between the BPII 2.0 and IKDC baseline scores taken at the initial consultation was 0.65 (P<0.001; 95% confidence interval, 0.94-0.97). The intraclass correlation coefficient (2,k) for the test-retest subsample (n=30) was 0.94. Patient interviews revealed that they thought the BPII 2.0 questions were both important and comprehensible.

CONCLUSIONS

The BPII 2.0 is a valid, reliable, and disease-specific patient-reported outcome measure that can be used with an adolescent population with lateral patellofemoral instability. The BPII 2.0 has demonstrated criterion validity through its moderately strong correlation to the Pedi-IKDC for adolescents.

Psychometric properties of the Norwich Patellar Instability Score in people with recurrent patellar dislocation

BACKGROUND

Patellar dislocations account for two percent of all knee injuries with a 17% chance of re-dislocation. There are few validated scores specific to instability. One of these is the Norwich Patellar Instability Score. There has been limited assessment of the validity, floor-ceiling effect and responsiveness of the Norwich Patellar Instability (NPI) Score from an independent centre. The purpose of this paper is to address this limitation.

METHODS

Data from 90 patients referred to a tertiary referral patellofemoral clinic were analysed. All routinely completed data including NPI Score, Kujala Patellofemoral Disorder Score, and demographic outcomes during appointments, up to 36 months following initial clinical assessment was analysed. Convergent validity was assessed by correlating outcomes of the Kujala Patellofemoral Disorder Score to the NPI Score. Effect size (ES) was determined between baseline to 12-month and 12 to 36-month assessments to determine responsiveness. Floor-ceiling effect was evaluated at baseline, 12-month and 12 to 36-month follow-up.

RESULTS

NPI Score demonstrated good convergent validity to the Kujala Patellofemoral Disorder Score (p < .001; 95% confidence interval (CI): -0.71 to -0.52). NPI Score demonstrated good responsiveness to change both between baseline to 12 months (ES: 0.43; 95% CI: 0.42 to 0.10) and 12 to 36 months (ES: 0.67; 95% CI: 0.60 to 0.15). Whilst the NPI Score did not demonstrate a ceiling effect, there was moderate risk of a floor-effect where 13% of the cohort reported the lowest levels of NPI scores.

CONCLUSIONS

The NPI Score is a valid and responsive outcome for people with recurrent patellar dislocation.

Trochleoplasty provides good clinical outcomes and an acceptable complication profile in both short and long-term follow-up

PURPOSE

The purpose of this study is to report on the global distribution and clinical outcomes of published articles related to trochleoplasty.

METHODS

The online databases OVID Medline, OVID EMBASE, and the Cochrane Library were searched for the literature assessing trochleoplasty performed for lateral patellofemoral instability (LPI). Study data were abstracted looking at global trends in the literature, as well as clinical and patient-reported outcomes following this technique.

RESULTS

For the assessment of global distribution, 29 studies including 998 patients met the inclusion criteria. The majority of the studies were conducted in Europe (93%) and most used an open thin flap technique (52%). For the secondary analysis of clinical outcomes, 21 studies were included with significant heterogeneity in patient selection, reporting on the degree of trochlear dysplasia, and patient-reported outcomes. All trochleoplasty techniques showed statistically significant improvement in clinical outcomes at average 50 months (range 3-228 months) post-operative, with most patients being satisfied with their procedure. Re-dislocation and complication rates were low.

CONCLUSIONS

European centers have published majority of data on trochleoplasty surgery, which has been shown to be an acceptable procedure for patients with high-grade trochlear dysplasia and LPI. Trochleoplasty has demonstrated good clinical outcomes, a low re-dislocation rate, and an acceptable complication profile in both short and long-term follow-up. This study highlights the difficulty in reporting outcomes in this group of patients due to heterogeneity in patient selection, grading of trochlear dysplasia, and the lack of disease-specific outcome measures.

LEVEL OF EVIDENCE

IV.

Translation, cross-cultural adaptation and validation of the Norwich Patellar Instability score for use in Brazilian Portuguese

BACKGROUND

The Norwich Patellar Instability (NPI) score is a tool for evaluating the impact of patellofemoral instability on joint function. It has not been translated or culturally adapted for the Brazilian population before.

OBJECTIVE

This study had the aims of translating and culturally adapting the NPI score for use in Brazilian Portuguese and subsequently assessing its validity for this population.

DESIGN AND SETTING

Translation, cross-cultural adaptation and validation study conducted at the State Public Servants' Institute of São Paulo, Brazil.

METHODS

Sixty patients of both sexes (aged 16-40 years) with diagnoses of patellar dislocation were recruited. The translation and cultural adaptation were undertaken through translation into Brazilian Portuguese and back-translation to English by an independent translator. Face validity was assessed by a committee of experts and by 20 patients. Concurrent validity was assessed through comparing the Brazilian Portuguese NPI score with the Brazilian Portuguese versions of the Lysholm knee score and the Kujala patellofemoral disorder score among the other 40 patients. Correlation analysis between the three scores was performed using Pearson correlation coefficients with significance levels of P < 0.05.

RESULTS

The Brazilian Portuguese version of the NPI score showed moderate correlation with the Brazilian Portuguese versions of the Lysholm score (r = -0.56; 95% confidence interval, CI: -0.74 to -0.30; P < 0.01) and Kujala score (r = -0.57; 95% CI: -0.75 to -0.31; P < 0.01).

CONCLUSION

The Brazilian Portuguese version of the NPI score is a validated tool for assessing patient-reported patellar instability for the Brazilian population.

Patient-Reported Outcome Measures for Patellofemoral Instability: a Critical Review

PURPOSE OF REVIEW

The purpose of this paper was to review the current psychometric properties of patient-reported outcome measures that are commonly used for patients with patellofemoral instability. This review provides evidence to guide the selection of subjective outcome measures for assessing outcomes in clinical care and research studies.

RECENT FINDINGS

At the present time, there are two patient-reported outcome measures that have been designed for, and tested on, large cohorts of patellofemoral instability patients, the Banff Patella Instability Instrument (BPII) and the Norwich Patellar Instability Score (NPI). The BPII is a wholistic quality of life outcome measure and the NPI is a symptom score. The use of disease-specific outcome measures such as the BPII and NPI, in combination with generic knee, functional activity, and/or psychological outcome measures that have been proven to be valid and reliable for the patellofemoral instability population, is most likely to provide a well-rounded evaluation of treatment outcomes.

Validity, Reliability, and Responsiveness of the Banff Patellar Instability Instrument (BPII) in a Adolescent Population

BACKGROUND

Health-related quality of life measures for the adolescent patellar instability population are limited. The Banff Patella Instability Instrument (BPII) is a disease-specific health-related quality of life that has been tested on a mixed adult and adolescent population but has not been exclusively tested with an adolescent population. The purpose of this study was to determine the validity, reliability, and responsiveness of the BPII within an adolescent population.

METHODS

Content validation was tested with 3 measures: floor and ceiling effects; the Cronbach alpha; readability grade level. Reliability was measured with an intraclass correlation coefficient (2, k) and the SEM. Responsiveness was measured using a 1-way analysis of variance comparing preoperative BPII scores to postoperative BPII scores at 6, 12, and 24 months. Eta squared was calculated to measure effect size.

RESULTS

The BPII demonstrated no floor or ceiling effects. The Cronbach alpha for the BPII ranged from 0.97 to 0.98 for the preoperative and postoperative time periods. The readability index was a mean grade level of 8.9. Test-retest reliability assessment demonstrated an intraclass correlation coefficient (2, k) of 0.99 indicating strong reliability. The SEM was 1.3. There was a statistically significant difference in BPII scores for the 4 different time interval measures (F3, 176=50.04; P<0.001). Eta squared was 0.46 demonstrating a moderate to large effect.

CONCLUSIONS

The BPII demonstrated validity, reliability, and responsiveness in an adolescent population. Furthermore, it has demonstrated an appropriate cognitive reading grade level of 8.9, commensurate with the mean age (16.08 y) of the population tested.

LEVEL OF EVIDENCE

Level III.

Successful adaption of the Banff Patella Instability Instrument (BPII) 2.0 into German

PURPOSE

The aim of this study was to adapt, translate, and validate the Banff Patella Instability Instrument (BPII) 2.0 into German, enabling its use by German-speaking professionals for the evaluation of patients who present with patellofemoral instability.

METHODS

Forward and backward translation was performed according to international recommendations. The final German version of the BPII 2.0 was investigated in patients with confirmed diagnoses of recurrent patellofemoral instability in Germany, Austria, and Switzerland. All patients received two packages of questionnaires, each containing the BPII 2.0, Kujala scoring questionnaire, Norwich Patella Instability scoring questionnaire, Short Form-36 (SF-36), and a visual analogue scale (VAS)-scale for pain and disability. The first and second packages of questionnaires were to be completed 7 days apart. The following parameters were assessed: internal consistency, test-retest reliability, floor and ceiling effects, and construct validity.

RESULTS

The study population consisted of 64 patients (24 males and 40 females). The average age of the patients was 22 ± 6 years. The internal consistency (Cronbach's alpha) was excellent at both time points (0.93 and 0.95), and the test-retest reliability (ICC) was good (0.89). There were no floor or ceiling effects. There were statistically significant correlations between the BPII 2.0 and all other outcome measures apart from SF-36 mental health.

CONCLUSION

The BPII 2.0 was successfully adapted into German. It is a reliable and valid instrument for evaluation of German-speaking patients who present with patellofemoral instability.

LEVEL OF EVIDENCE

III.

Clinical Outcomes After the Nonoperative Management of Lateral Patellar Dislocations: A Systematic Review

Background:

The first-line treatment for patellar dislocations is often nonoperative and consists of physical therapy and immobilization techniques, with various adjuncts employed. However, the outcomes of nonoperative therapy are poorly described, and there is a lack of quality evidence to define the optimal intervention.

Purpose:

To perform a comprehensive review of the literature and assess the quality of studies presenting patient outcomes from nonoperative interventions for patellar dislocations.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

The MEDLINE, AMED, Embase, CINAHL, Cochrane Library, PEDro, and SPORTDiscus electronic databases were searched through July 2017 by 3 independent reviewers. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Study quality was assessed using the CONSORT (Consolidated Standards for Reporting Trials) criteria for randomized controlled trials and the Newcastle-Ottawa Scale for cohort studies and case series.

Results:

A total of 25 studies met our inclusion criteria, including 12 randomized controlled trials, 7 cohort studies, and 6 case series, consisting of 1066 patients. Studies were grouped according to 4 broad categories of nonoperative interventions based on immobilization, weightbearing status, quadriceps exercise type, and alternative therapies. The most commonly used outcome measure was the Kujala score, and the pooled redislocation rate was 31%.

Conclusion:

This systematic review found that patient-reported outcomes consistently improved after all methods of treatment but did not return to normal. Redislocation rates were high and close to the redislocation rates reported in natural history studies. There is a lack of quality evidence to advocate the use of any particular nonoperative technique for the treatment of patellar dislocations.

Recent developments in evaluation and treatment of lateral patellar instability

Recent years have been characterized by an ongoing increase in knowledge about the different conditions associated with lateral patellar instability. This increase in knowledge provides differentiated approaches to the various pathologies of the patellofemoral joint. Though current guidelines consider medial patellofemoral ligament (MPFL) reconstruction the basic treatment for the unstable patella, medial soft tissue-stabilizing procedures should not be interpreted as stand-alone procedures in every case. The influence of different anatomical factors leading to patellar instability, as well as their impact on clinical outcome measures, is becoming increasingly apparent and deserves further attention. Therefore, the purpose of this review was to summarize recent developments in lateral patellar instability beyond MPFL reconstruction techniques. For this goal, the literature published within the last 3 years considering all aspects of lateral patellar instability was analysed. Six main topics evolved according to the number of publications and in terms of novel aspects and recent developments in the evaluation and treatment of lateral patellar instability. Those topics formed the basis of this article: (1) treatment of first-time patellar dislocation, (2) the impact of trochlear dysplasia and trochleoplasty procedures, (3) the relevance of torsional deformities, (4) patellar instability in open physis, (5) the implementation of new outcome measures, and (6) rehabilitation after patellar stabilizing procedures.

Results of medial patellofemoral ligament reconstruction compared with trochleoplasty plus individual extensor apparatus balancing in patellar instability caused by severe trochlear dysplasia: a systematic review and meta-analysis

PURPOSE

Many studies have reported satisfactory clinical outcomes and low redislocation rates after reconstruction of the medial patellofemoral ligament (MPFL) for the treatment of lateral patellar instability. Despite uncorrected severe trochlear dysplasia (Dejour type B to D) being acknowledged as a major reason for less favourable clinical outcomes and a higher incidence of patellar redislocations after an isolated MPFL reconstruction, the evidence for a deepening trochleoplasty procedure remains scarce in the current literature. The hypothesis of this systematic review and meta-analysis was that a deepening trochleoplasty in combination with an a la carte extensor apparatus balancing procedure provides lower redislocation rates and superior clinical outcomes than isolated MPFL reconstruction in patients with lateral patellar instability caused by severe trochlear dysplasia.

METHODS

A systematic review of the literature was conducted using specific inclusion and exclusion criteria for clinical studies reporting index operations (trochleoplasty and MPFL reconstruction) for the treatment of patellar instability caused by severe trochlear dysplasia. The Kujala score was analysed as the primary clinical outcome parameter in a random effects meta-analysis.

RESULTS

Ten uncontrolled studies with a total of 407 knees (374 patients) were included in this analysis. The MPFL group comprised 4 studies with a total of 221 knees (210 patients), and the trochleoplasty group comprised 6 studies with a total of 186 knees (164 patients). The mean preoperative Kujala score ranged between 50.4 and 70.5 in the MPFL group and between 44.8 and 75.1 in the trochleoplasty group. The pooled Kujala score increased significantly by 26.4 (95% CI 21.4, 31.3; P < 0.00001) points in the MPFL group and by 26.2 (95% CI 19.8, 32.7; P < 0.00001) points in the trochleoplasty group. The post-operative patellar redislocation/subluxation rate was 7% in the MPFL group and 2.1% in the trochleoplasty group.

CONCLUSION

This analysis found significant post-operative improvements in patient-reported outcomes for patients undergoing both an MPFL reconstruction and in those undergoing a trochleoplasty plus an individual extensor apparatus balancing procedure when assessed using the Kujala score. The likelihood of preventing the patella from subsequent post-operative redislocation/subluxation was, however, greater in patients who underwent trochleoplasty plus extensor balancing.

LEVEL OF EVIDENCE

IV.

An evaluation of the effectiveness of medial patellofemoral ligament reconstruction using an anatomical tunnel site

PURPOSE

Medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability has gained popularity, and anatomical and biomechanical studies have recently altered our operative techniques. The aim of this study was to report the clinical outcome of this new anatomical MPFL reconstructive technique and investigate whether correlating factors could be identified.

METHODS

Between 2009 and 2012, a total of 31 consecutive patients underwent MPFL reconstruction using an autologous gracilis graft and anatomical tunnel placement. Pre- and post-operative data were collected as a part of routine clinical practice. The preoperative assessment included a rotational profile CT scan of the lower extremity according to the Lyon protocol with TT-TG distance measurement. Outcomes were evaluated with the Kujala and Norwich patella instability (NPI) scores preoperatively and at follow-up (1.5-5.1 years).

RESULTS

A significant improvement in both the Kujala (p < 0.001) and NPI (p = 0.012) scores was recorded. A medium and large negative correlations were found between TT-TG distance and Kujala score improvement (ρ = -0.48, p = 0.020) and NPI score improvement (ρ = -0.83, p = 0.042), respectively. Multiple regression analysis identified TT-TG distance, Beighton score and BMI as factors explaining the variance of Kujala score improvement.

CONCLUSION

Anatomical MPFL reconstruction with the gracilis autograft for patellar instability resulted in good outcome. This underlines the importance of anatomical tunnel placement in MPFL reconstruction. With a precise preoperative work-up, factors can be identified that may guide selecting the optimal operative strategy and improve counselling of the patient.

LEVEL OF EVIDENCE

Case series, Level IV.

The Elbow Self-Assessment Score (ESAS): development and validation of a new patient-reported outcome measurement tool for elbow disorders

PURPOSE

To develop and validate an elbow self-assessment score considering subjective as well as objective parameters.

METHODS

Each scale of the American Shoulder and Elbow Surgeons-Elbow Score, the Broberg and Morrey rating system (BMS), the Patient-Rated Elbow Evaluation (PREE) Questionnaire, the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score (OES) and the Quick Disabilities of the Arm, Shoulder and Hand (Quick-DASH) was analysed, and after matching of the general topics, the dedicated items underwent a fusion to the final ESAS's item and a score containing 22 items was created. In a prospective clinical study, validity, reliability and responsiveness in physically active patients with traumatic as well as degenerative elbow disorders were evaluated.

RESULTS

Validation study included 103 patients (48 women, 55 men; mean age 43 years). A high test-retest reliability was found with intraclass correlation coefficients of at least 0.71. Construct validity and responsiveness were confirmed by correlation coefficients of -0.80 to -0.84 and 0.72-0.84 (p <0.05). Correlation coefficients of the ESAS and well-established elbow rating systems BMS, PREE, MEPS, OES and Quick-DASH were between 0.70 and 0.90 (p < 0.05).

CONCLUSIONS

With this novel Elbow Self-Assessment Score (ESAS), a valid and reliable instrument for a qualitative self-assessment of subjective and objective parameters (e.g. range of motion) of the elbow joint is demonstrated. Quantitative measurement of elbow function may not longer be limited to specific elbow disorders or patient groups. The ESAS seems to allow for a broad application in clinical research studying elbow patients and may facilitate the comparison of treatment results in elbow disorders. The treatment efficacy can be easily evaluated, and treatment concepts could be reviewed and revised.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

Pediatric patellar dislocation

Acute patellar dislocation affects approximately 1:1000 healthy children 9-15 years of age, and up to 50% are at risk for recurrent dislocations. In adults the condition is associated with long-term complications, such as osteoarthritis and impairment of knee function. However, literature describing the outcome in a pediatric population is sparse. The present review article evaluates the long-term effects on knee function and cartilage quality after traumatic patellar dislocation in childhood, and also to evaluate the reliability of two clinical tests of medio-lateral knee position, in healthy children.

Patellar instability: CT and MRI measurements and their correlation with internal derangement findings

PURPOSE

To test the inter-observer and inter-method reliability among the measures suggesting patellofemoral joint disorder on both CT and MRI in the same subject and find possible association with internal derangements of the patellofemoral joint on MRI.

METHODS

Institutional review board approval was obtained with waiver of the informed consent in this HIPPA-compliant study. CT and MRI were evaluated in 32 knees in 32 respective subjects (10 men/22 women, mean age 38 ± 19 years). Three trained observers assessed tibial tuberosity-trochlear groove (TT-TG) distance, trochlear angle and trochlear depth on both CT and MRI. Intra-class correlation coefficient (ICC) was used to evaluate inter-observer and inter-method reliability. Two radiologists' consensus reading was used to evaluate their association with soft tissue abnormalities of the patellofemoral joint. Chi-square test was used to assess the statistical significance of the qualitative variables.

RESULTS

There was an excellent inter-observer reliability (ICC for CT >0.89 and for MRI >0.90) and inter-method reliability (ICC >0.86) for all the quantitative measurements. There was a significant association between increased TT-TG distance value on MR imaging and lateral facet patellar cartilage abnormality and joint effusion (p < 0.05).

CONCLUSION

Quantitative trochlear parameters can be reliably calculated on MRI, and an abnormal TT-TG distance is the most useful measurement among various static MR imaging parameters to correlate with patellar chondrosis and joint effusion. TT-TG distance should be reported in patellofemoral pain syndrome patients.

LEVEL OF EVIDENCE

IV.

Concurrent Validation of the Banff Patella Instability Instrument to the Norwich Patellar Instability Score and the Kujala Score in Patients With Patellofemoral Instability

Background:

The Banff Patella Instability Instrument (BPII) is a disease-specific, patient-reported, quality-of-life outcome measure designed to assess patients with patellofemoral instability. The iterative assessment of the validity, reliability, and responsiveness of a health-related patient-reported outcome measure is vital to the development of a high-quality evaluation tool.

Purpose:

To assess the concurrent validity of the BPII to the Norwich Patellar Instability (NPI) score and the Kujala score.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 74 patients with a confirmed diagnosis of recurrent patellofemoral instability completed the BPII, NPI, and Kujala scores at the initial orthopaedic consultation. A Pearson r correlation coefficient was computed to determine the relationship between each of these patient-reported outcomes.

Results:

There were statistically significant correlations between the BPII and the NPI score (r = −0.53; P < .001) as well as the BPII and the Kujala score (r = 0.50; P < .001).

Conclusion:

This study demonstrated a moderately strong correlation of the BPII to other outcome measures used to evaluate patients with patellofemoral instability. This study adds further validity to the BPII in accordance with the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) guidelines.

The Munich Wrist Questionnaire (MWQ) - development and validation of a new patient-reported outcome measurement tool for wrist disorders

Background

Although self-assessment questionnaires for the wrist joint are numerous, most validation studies focus on a specific pathology and patient collectives. In addition the available questionnaires focus on subjective parameters such as pain, usual and specific activities but the range of motion (ROM) as an essential objective parameter in wrist disorders is rarely considered. Therefore the purpose of the presented study was to develop and validate a new universally applicable self-assessment score, the Munich Wrist Questionnaire (MWQ), which allows for the assessment of subjective as well as objective parameters of the wrist joint.

Methods

The MWQ consists of 16 items addressing three domains: pain, work and activities of daily living and wrist function including range of motion and grip strength. In a prospective clinical study validity, reliability and responsiveness of the MWQ of physical active patients were evaluated.

Results

Validation study included 100 patients (mean age 41 years, SD 16.3 years; range, 18–77 years). Test-retest reliability was substantial, with intraclass correlation coefficients ranging from 0.75 to 0.83 for the three domains. Construct validity and responsiveness were confirmed by correlation coefficients of at least 0.86 for construct validity and for responsiveness ranging from 0.61 to 0.65.

Conclusions

The MWQ presents a valid and reliable instrument for a qualitative self-assessment of subjective and objective parameters (e.g. range of motion) of the wrist joint. Quantitative measurement of wrist function may not longer be limited to specific wrist disorders or patient groups. The MWQ seems to allow for a broad application in clinical research and may facilitate the comparison of treatment results in wrist disorders.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1029-4) contains supplementary material, which is available to authorized users.

The Norwich Patellar Instability Score: Validity, internal consistency and responsiveness for people conservatively-managed following first-time patellar dislocation

BACKGROUND

This paper assessed the validity, internal consistency, responsiveness and floor-ceiling effects of the Norwich Patellar Instability (NPI) Score for a cohort of conservatively managed people following first-time patellar dislocation (FTPD).

METHODS

Fifty patients were recruited, providing 130 completed datasets over 12 months. The NPI Score, Lysholm Knee Score, Tegner Level of Activity Score and isometric knee extension strength were assessed at baseline, six weeks, six and 12 months post-injury.

RESULTS

There was high convergent validity with a statistically significant correlation between the NPI Score and the Lysholm Knee Score (p<0.001), Tegner Level of Activity Score (p<0.001) and isometric knee extension strength (p<0.002). Principal component analysis revealed that the NPI Score demonstrated good concurrent validity with four components account for 70.4% of the variability. Whilst the NPI Score demonstrated a flooring-effect for 13 of the 19 items, no ceiling effect was reported. There was high internal consistency with a Cronbach Alpha value of 0.93 (95% CI: 0.91 to 0.93). The NPI Score was responsive to change over the 12 months period with an effect size of 1.04 from baseline to 12 months post-injury.

CONCLUSIONS

The NPI Score is a valid tool to assess patellar instability symptoms in people conservatively managed following FTPD.

LEVEL OF EVIDENCE

Level II.

Deepening Trochleoplasty With a Thick Osteochondral Flap for Patellar Instability: Clinical and Functional Outcomes at a Mean 6-Year Follow-up

BACKGROUND

In patients with patellar instability and severe trochlear dysplasia, trochleoplasty has become increasingly used as part of its surgical management.

HYPOTHESIS

Deepening trochleoplasty for severe dysplasia in patellofemoral instability improves function and increases sports participation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 1995 and 2010, deepening trochleoplasty with a thick flap was performed in 90 patients (107 knees) with severe trochlear dysplasia. Data were collected prospectively preoperatively, at 6 weeks, and at 1-year follow-up. The patients were surveyed retrospectively to determine the clinical and functional outcomes including sports and exercise participation at a minimum of 2 years, with complete data available in 92%.

RESULTS

The average follow-up was 6 years (range, 2-19 years). The median Kujala score was 63 (interquartile range [IQR], 47-75) preoperatively, rising to 79 (IQR, 68-91) at 1-year follow-up and 84 (IQR, 73-92) at final follow-up (P < .05). Seventy-two percent were satisfied with their knee function at 1-year follow-up, rising to 83% at final follow-up (P < .0001). Sports and exercise participation increased from 36 patients (40%) preoperatively to 60 (67%) at final follow-up. The number of patients involved in competitions increased slightly from 10 (11%) to 11 (12%). Of those sports that involved twisting (e.g., soccer, cricket, badminton), the number of patients participating increased from 16 (18%) to 22 (24%), whereas in nontwisting sports (e.g., running, swimming, cycling), it increased from 24 (27%) to 47 (52%), of whom 12 (16%) used walking as exercise. Two patients who had undergone medial patellofemoral ligament (MPFL) reconstruction as the index operation needed the MPFL revised, and a further 8 patients needed MPFL reconstruction subsequently for instability symptoms and a mediolateral glide in extension of more than 2 quadrants' displacement. At final follow-up, no patient had mechanical patellofemoral instability.

CONCLUSION

Deepening trochleoplasty with a thick flap improves clinical and functional outcomes for patients with symptomatic patellar instability with severe trochlear dysplasia. These results improve over time and beyond 1-year clinical follow-up. However, trochleoplasty does not lead to a significant improvement in sports participation at a competitive level. It does improve patient participation in sports and exercise, principally in nontwisting sports activities.

Patellar instability factors in isolated medial patellofemoral ligament reconstructions--what does the literature tell us? A systematic review

BACKGROUND

Many studies have demonstrated good results after medial patellofemoral ligament (MPFL) reconstruction for patients with patellar instability. The applicability of published studies to the clinical decision-making process for the individual patient with patellar instability, however, is not well elucidated.

HYPOTHESIS

There is inconsistency in the reporting of preoperative and postoperative variables, which limits the applicability of current studies to patients with patellar instability.

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the literature was conducted using the search term medial patellofemoral ligament reconstruction to identify studies with cohorts of patients with isolated MPFL reconstruction. A combination of inclusion and exclusion criteria resulted in 24 studies being reviewed for a variety of preoperative demographics, physical examination findings, and imaging findings, as well as postoperative outcomes, including redislocation and responses to subjective questionnaires.

RESULTS

A physical examination of lateral patellar translation was reported in 42% of studies, by reporting an apprehension sign (n = 9), reporting quadrant translation (n = 7), or both. For patellar instability factors on imaging, patellar height was reported as a preoperative variable in 75% of studies, and trochlear dysplasia was reported in 83% of studies. The tibial tubercle-trochlear groove distance was reported as a preoperative variable in 42% of studies. The rate of redislocation after index surgery was reported in 92% of studies. Patient-related outcome measures were reported in all of the studies; the Kujala score was the most common. A homogeneous population was selected as part of the authors' surgical indications for "isolated" MPFL in 67% of studies, and a heterogeneous population was selected in 33% of studies.

CONCLUSION

Current literature on MPFL reconstruction contains diverse methods of recording preoperative and postoperative variables. Most studies report on a homogeneous population, with inconsistent applicability to the broad spectrum of patients with patellar instability. Outcomes reporting in our current literature needs more clarity and consistency regarding reporting methodology to be of value for the treating clinician.

Rehabilitation following first-time patellar dislocation: a randomised controlled trial of purported vastus medialis obliquus muscle versus general quadriceps strengthening exercises

BACKGROUND

We aimed to define whether distal vastus medialis (VM) muscle strengthening improves functional outcomes compared to general quadriceps muscle strengthening following first-time patellar dislocation (FTPD).

METHODS

Fifty patients post-FTPD were randomised to either a general quadriceps exercise or rehabilitation programme (n=25) or a specific-VM exercise and rehabilitation regime (n=25). The primary outcome was the Lysholm knee score, and secondary outcomes included the Tegner Level of Activity score, the Norwich Patellar Instability (NPI) score, and isometric knee extension strength at various knee flexion ranges of motion. Outcomes were assessed at baseline, six weeks, six months and 12months.

RESULTS

There were statistically significant differences in functional outcome and activity levels with the Lysholm knee score and Tegner Level of Activity score at 12months in the general quadriceps exercise group compared to the VM group (p=0.05; 95% confidence interval (CI): -14.0 to 0.0/p=0.04; 95% CI: -3.0 to 0.0). This did not reach a clinically important difference. There was no statistically significant difference between the groups for the NPI score and isometric strength at any follow-up interval. The trial experienced substantial participant attrition (52% at 12months).

CONCLUSIONS

Whilst there was a statistical difference in the Lysholm knee score and Tegner Level of Activity score between general quadriceps and VM exercise groups at 12months, this may not have necessarily been clinically important. This trial highlights that participant recruitment and retention are challenges which should be considered when designing future trials in this population.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

The Munich Knee Questionnaire: Development and Validation of a New Patient-Reported Outcome Measurement Tool for Knee Disorders

PURPOSE

To develop and validate an all-purpose patient-reported outcome questionnaire for a patient-based follow-up examination regarding knee disorders.

METHODS

Each scale of the Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score, Lysholm knee score, Western Ontario Meniscal Evaluation Tool (WOMET) score, and Tegner score was analyzed, and after matching of the general topics, the dedicated items underwent a fusion to the final Munich Knee Questionnaire (MKQ) item and a score comprising 33 items was created. In a prospective clinical study, we evaluated validity, reliability, and responsiveness in 152 physical active patients (75 women and 77 men; mean age, 47 years) with traumatic as well as degenerative knee disorders.

RESULTS

Test-retest reliability was substantial, with intraclass correlation coefficients of at least 0.91. Construct validity and responsiveness were confirmed by correlation coefficients of 0.78 to 0.86 (P = .01) and 0.41 to 0.71, respectively. Correlation coefficients of the original scores (KOOS, IKDC, Lysholm, WOMET, and Tegner) and the scores calculated from the MKQ were between 0.80 and 0.91 (P = .01).

CONCLUSIONS

The MKQ is a reliable and valid patient-reported outcome questionnaire for assessing knee function. It seems to enable the calculation of the original items of the KOOS, IKDC score, Lysholm knee score, WOMET score, and Tegner score.

CLINICAL RELEVANCE

The MKQ facilitates the comparison of treatment results in knee disorders and allows the evaluation of treatment efficacy. Identified inadequate treatment concepts could be eliminated, leading to increased patient satisfaction and optimized quality of health care.