Functional outcomes and return to sport following anterior cruciate ligament reconstruction in recreational athletes: A systematic review.

INTRODUCTION: Outcomes of anterior cruciate ligament reconstruction (ACLR) are well reported in athletic populations, however surprisingly little information is available for the recreational athletes that make up the majority of cases. The aim was therefore to assess post-operative outcome and return-to-sport in recreational athletes following ACLR. METHODS: A systematic search was conducted in Ovid MEDLINE, CINAHL, AMED and the grey literature according to PRISMA guidelines. Studies involving a clear definition of recreational athletes who underwent ACLR and recorded postoperative outcomes were included. Publication quality was assessed using Newcastle-Ottawa Scale. RESULTS: 107 studies were identified, 19 full-text records reviewed and 13 included, reflecting 1342 patients with an average age of 31.7 (SD 9.8) years. Mean follow-up was 43.6 (SD 42.8) months. Activity change post-surgery was reported in 92% (12/13) papers. Outcomes were assessed with the Tegner score in seven studies, four of which reported pre-injury scores, which worsened from 5.4 to 4.3 at final follow-up (76.5 months). 54% (7/13) studies reported return to pre-injury level of sport. In these, 59% (n = 327/555) achieved pre-injury level at a mean follow-up of 33.7 months (SD 38.6). The return-to-sports rate increased with length of follow-up. Methodological quality was moderate. CONCLUSION: Substantial variation in the timeframes and outcomes assessed restricts pooled analysis of change in function. Based on seven studies, 59% of recreational athletes return to pre-injury level of sport following ACLR. The link between return rate and post-operative review timeframe suggests that longer follow-up may be required to capture return-to-sport rates in this population.

Morphological and functional properties distinguish the substance P and gastrin-releasing peptide subsets of excitatory interneuron in the spinal cord dorsal horn.

Excitatory interneurons account for the majority of neurons in the superficial dorsal horn, but despite their presumed contribution to pain and itch, there is still limited information about their organisation and function. We recently identified 2 populations of excitatory interneuron defined by expression of gastrin-releasing peptide (GRP) or substance P (SP). Here, we demonstrate that these cells show major differences in their morphological, electrophysiological, and pharmacological properties. Based on their somatodendritic morphology and firing patterns, we propose that the SP cells correspond to radial cells, which generally show delayed firing. By contrast, most GRP cells show transient or single-spike firing, and many are likely to correspond to the so-called transient central cells. Unlike the SP cells, few of the GRP cells had long propriospinal projections, suggesting that they are involved primarily in local processing. The 2 populations also differed in responses to neuromodulators, with most SP cells, but few GRP cells, responding to noradrenaline and 5-HT; the converse was true for responses to the µ-opioid agonist DAMGO. Although a recent study suggested that GRP cells are innervated by nociceptors and are strongly activated by noxious stimuli, we found that very few GRP cells receive direct synaptic input from TRPV1-expressing afferents, and that they seldom phosphorylate extracellular signal-regulated kinases in response to noxious stimuli. These findings indicate that the SP and GRP cells differentially process somatosensory information.