Age at surgery is correlated with pain scores following trochlear osteotomy in lateral patellar instability: a cross-sectional study of 113 cases.

BACKGROUND: A trochlear osteotomy aims to restore patellar stability in patients with recurrent patellar instability and trochlear dysplasia. The age of patients at time of surgery could be a relevant factor which influences outcome. We hypothesized that lower age at time of surgery is associated with better patient-reported outcomes. METHODS: A retrospective study was conducted on patients with patellar instability and trochlear dysplasia. Patients were contacted by phone for informed consent and were then asked to complete online patient-reported outcome measurements (PROMs). The PROMs consisted of the Kujala Knee Score (KKS) (Kujala et al., Arthroscopy 9(2):159-63, 1993; Kievit et al. Knee Surg Sports Traumatol Arthrosc. 21(11):2647-53, 2013), the Short Form 36-item health survey (SF-36v1) (Ware, Med Care 73-83, 1992; Aaronson et al., J Clin Epidemiol. 51(11):1055-68, 1998), and visual analog scale (VAS) scoring pain, instability, disability, and satisfaction on a 0-100 scale. Multivariable linear regression models were used to study the effect of age on the PROM scores. RESULTS: For this study, 125 surgical procedures in 113 patients were included. Mean VAS pain at rest was 19 and at activity 38; mean Kujala score was 73. Multivariable regression analysis revealed that age at the time of surgery was correlated with VAS pain at rest, with a 0.95 increase of VAS score (scale 0-100) for every year of age. Recurrence of instability was observed in 13 (10%) knees. CONCLUSION: In this cross-sectional study, pain scores of 113 patients who have undergone a lateral facet elevating trochlear osteotomy for patellar instability were reported. Age at time of surgery was correlated with an increased pain score at rest with an average of 9.5 points (scale 0-100) for every 10 years of age. Age at time of surgery was not correlated with overall satisfaction.

Complications of a self-centering sliding tibial tubercle osteotomy for patellofemoral complaints; low incidence of non-union and fracture.

BACKGROUND: A tibial tubercle osteotomy (TTO) is a commonly performed procedure in young and active patients with patellofemoral complaints. Previous small patient series demonstrated a relatively high risk of complications, which appear to be technique dependent. The purpose of this large case series is to quantify the risk of procedure specific postoperative complications related to a uniform self-centering TTO technique in a large cohort, performed by two different surgeons in one center. HYPOTHESIS: We hypothesize that non-union or fracture occurs in less than 1% of the procedures. PATIENTS AND METHODS: Five hundred and twenty-nine knees in four hundred and forty-seven patients who underwent a self-centering TTO with at least one year of follow-up were included. We performed a retrospective cohort review. Tibial fracture, osteotomy non-union, neurovascular complications, infection and wound complications that required surgical intervention were defined as major complications, miscellaneous complications were defined minor. RESULTS: The major finding in this study is the low incidence of non-union (0.6%) and tibial fracture (0.4%). In total 9 (1.7%) major complications were reported. Minor complications included superficial wound infection in five patients, two patients had a venous thrombo-embolism (VTE). CONCLUSION: A self-centering TTO is a relatively safe technique with a low number of non-union and fracture. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

A detaching, V-shaped tibial tubercle osteotomy is a safe procedure with a low complication rate.

INTRODUCTION: In patients with recurrent patellar dislocations, a tibial tubercle osteotomy (TTO) can be indicated to correct patella alta or an increased trochlear groove-tibial tubercle distance. Several surgical techniques are described. Previous studies emphasize that detaching osteotomies results in devascularisation, which can lead to non-union and tibial shaft fractures. The aim of this study was to report the complication rates directly related to the surgical technique of a V-shaped TTO, where the tubercle is completely released from its periosteum using a step-cut osteotomy. METHODS: The retrospective case series comprised a large cohort of 263 knees with patella alta in 203 patients who underwent a V-shaped TTO, with or without additional realignment procedures, between March 2004 and October 2017. Data were obtained from available patient files. Complications were defined as minor or major. RESULTS: Thirteen major complications were registered (4.9%) including two tibial fractures (0.75%) and one non-union (0.37%). Five complications (1.9%) were defined as minor. Removal of the screws because of irritation or pain was seen in 22 cases (8.2%). CONCLUSION: A V-shaped TTO is a safe procedure. The presumed higher risk for tibial fractures or pseudo-arthrosis could not be confirmed.

Dutch translation and validation of the Norwich Patellar Instability score and Banff Patella Instability Instrument in patients after surgery for patellar instability.

Recently, two new English specific patient reported outcome measures (PROMs) to evaluate treatment of patients with patellofemoral complaints have been developed : the Banff Patella Instability Instrument (BPII) and the Norwich Patellar Instability (NPI) score. This study was designed to translate and validate the BPII and NPI in Dutch patients after surgical treatment for patellar instability. Forward and backward translation of the outcome measures was performed. Patients who had been surgically treated for patellar instability filled out the NPI and BPII together with the Kujala Knee Score, numeric rating scales, Knee disability and Osteoarthritis Outcome Score (KOOS) and SF- 36. We assessed internal consistency and construct validity. We evaluated the presence of ceiling and floor effects. Ninety-seven patients completed the online questionnaires. The internal consistency of the NPI and BPII score was excellent for both outcome measures. The BPII and NPI had good correlations with other PROMs. For the BPII we found no floor nor ceiling effect. For the NPI we found a floor effect but no ceiling effect. Our results indicate that the Dutch version of the BPII and the NPI can be used for patients with patellar instability. Both PROMs have specific (dis) advantages.

Patellar height measurements: Insall-Salvati ratio is most reliable method.

PURPOSE: Patella alta is a risk factor for patellofemoral pain and instability. Several measurement methods and imaging modalities are in use to measure patellar height. The first aim of this study was to determine the intra- and interrater reliability of different patellar height measurement methods on conventional radiography (CR), CT and MRI. The second aim was to examine the applicability of patellar height measurement methods originally designed for CR on CT and MRI. METHODS: Forty-eight patients who were treated for patellar instability were included. All patients had undergone a pre-operative conventional radiograph, CT scan and MRI. Five methods for measuring patellar height were performed on radiographs, CT and MRI by four observers. For each measurement, the intra- and interrater reliability was determined by calculating the intra-class correlation coefficient (ICC). A Bland-Altman analysis was performed for measurements with an ICC ≥ 0.70. RESULTS: The Insall-Salvati (IS) ratio was the only measurement that showed good intra- and inter-observer reliability on CR, CT and MRI. The intra- and inter-observer reliability of the patellotrochlear index (PTI) for MRI was good to excellent for all observers. The IS ratio showed a moderate to good reliability for comparison of all three imaging modalities with the best agreement between radiography and MRI. The other patellar height measurements showed only poor to moderate inter-method agreement. CONCLUSION: In this study, the Insall-Salvati ratio shows better intra- and inter-observer reliability than the Blackburne-Peel ratio, the Caton-Deschamps ratio and the modified Insall-Salvati ratio on all imaging modalities. Radiography and CT seem to have better reliability than MRI. The patellotrochlear index, however, shows good inter- and intra-observer reliability on MRI. Only for the IS method was there acceptable agreement between CR and MRI. This means that the established Insall-Salvati normal values could be used for MRI as well. This study shows that the most reliable method to measure patella height is the Insall-Salvati ratio measured on conventional radiographs or the patellotrochlear index on MRI. LEVEL OF EVIDENCE: Level II diagnostic.

Trochleoplasty procedures show complication rates similar to other patellar-stabilizing procedures.

PURPOSE: Trochleoplasty aims to restore patellar stability. Various techniques have been described and almost all authors report successful results. However, the procedure has a significant risk of complications. Purpose of this study was to perform a systematic review and meta-analysis of the available literature to assess the rate of complications after the various techniques used for trochleoplasty procedures. MATERIALS AND METHODS: MEDLINE, EMBASE, Web of Science and Cochrane Library databases were searched. Studies on patients with recurrent patellar instability treated with a trochleoplasty with or without additional procedure, and reported complications were included. The primary outcome was the rate of complications per technique. A meta-analysis was performed whenever three or more studies per surgical technique could be included. RESULTS: The selection process resulted in 20 studies included for analysis. A lateral facet elevating trochlear osteotomy was reported by two studies, ten studies reported on a Bereiter trochleoplasty, five on a Dejour trochleoplasty, one on an arthroscopic technique, one on a 'modified' technique and one on a recession wedge trochleoplasty. Meta-analysis showed that proportion of recurrent dislocation was 0.04 (95% CI 0.02-0.07) for Bereiter trochleoplasty and 0.02 (95% CI 0-0.08) for Dejour trochleoplasty. These proportions were 0.06 (95% CI 0.02-0.13) and 0.09 (95% CI 0.03-0.27) for recurrent instability, 0.07 (95% CI 0.02-0.19) and 0.12 (95% CI 0.00-0.91) for patellofemoral osteoarthritis and 0.08 (95% CI 0.04-0.14) and 0.20 (95% CI 0.11-0.32) for further surgery respectively. CONCLUSION: This study demonstrates that the complications after a Bereiter and Dejour trochleoplasty including additional procedures are in the range of those of other patellar stabilizing procedures. For four other techniques, no meta-analysis could be performed. The clinical relevance of this study is that it provides clinicians with the best currently available evidence on the rate of complications after trochleoplasty procedures. This can be helpful in the process of deciding whether or not to perform such a procedure, and can be used to better inform patients about the advantages and disadvantages of different trochleoplasty procedures. LEVEL OF EVIDENCE: Level IV.