Purpose Patellofemoral pain syndrome (PFPS) is a common pathology usually presenting with anterior or retropatellar pain. It is associated with a relative imbalance between the vastus medialis oblique (VMO) and the vastus lateralis (VL) muscles. This can lead to considerable morbidity and reduced quality of life (QOL). This study aims to assess the long-term functional outcome of PFPS treated with VL muscle botulinum toxin A (BoNT-A) injection. Materials and methods A retrospective review was performed on 26 consecutive patients (31 knees) with a mean age of 50.1 years (± 19.7 years) who were treated with BoNT-A injections to the VL muscle followed by physiotherapy between 2008 and 2015. Pre- and post-treatment pain levels (numerical rating scale, NRS), QOL (SF-6D), and functional scores (Kujala and Lysholm questionnaires) were measured. Demographics, physical therapy compliance, previous surgeries, perioperative complications, and patient satisfaction levels were collected. Results The mean follow-up time was 58.8 ± 36.4 months. There were significant improvements in all the examined domains. The average pain score (NRS) decreased from 7.6 to 3.2 (P < 0.01), and the Kujala, Lysholm, and SF-6D scores improved from 58.9 to 82.7 (P < 0.001), 56.2 to 83.2 (P < 0.001), and 0.6 to 0.8 (P < 0.001), respectively. Similar delta improvement was achieved irrespective of gender, age, compliance to post-treatment physical therapy, or coexisting osteoarthritis. Patients who presented with a worse pre-treatment clinical status achieved greater improvement. Prior to BoNT-A intervention, 16 patients (18 knees) were scheduled for surgery, of whom 12 (75%, 13 knees) did not require further surgical intervention at the last follow-up. Conclusions A single intervention of BoNT-A injections to the VL muscle combined with physiotherapy is beneficial for the treatment of patients with persistent PFPS. Level III evidence Retrospective cohort study.

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Introduction: Chronic infections after a total hip arthroplasty (THA) are a devastating complication and are usually treated by a complete revision of components. Selective revision, with preservation of well-fixed components, has been previously reported. We did a systematic review to report on success rates of selective revision in chronic infections after THA. Methods: PubMed, Web of Science, and the Cochrane Database were systematically searched for studies reporting on partial-retaining revision for chronically infected THA. These were reviewed to determine success rates based on component revised, as well as infectious organism. Results: Nine studies reported on 134 patients. The majority of the patients underwent femoral-retaining procedures (118), and the rest of the patients underwent acetabular-retaining procedures (16). Average follow-up was 60.56 months, and the success rates were 80% for femoral revision, 90.43% for acetabular revision, and overall success rate was 89.41%. Discussion: In select patients, retainment of well-fixed components in chronically infected THA may be considered. Although reported success rates are high, and comparable with complete revision arthroplasty in cases of chronic infections, the quality of the studies included is poor. The studies lacked sufficient internal validity, sample size, methodological consistency, and standardization of protocols and outcomes. Level of Evidence: Systematic review of level IV studies