Admittedly if the New Testament did not quote this passage as applied to Christ, I would be leery about understanding it as Messianic. I have not studied this Psalm carefully but it basically seems to be describing how God rescued David in a situation where some suffering was required. Yet his care, in David's suffering, is still evident in that not 'one bone was broken'. In other words as applied to the godly in their trials, it may seem that the world, or the Devil can harm us but yet even in our dire straights nothing can harm us, unless God allow it. In our trouble we are yet divinely assisted, preserved and swallowed up in his ultimate plan of salvation, whereas the wicked are simply destroyed in the final end. However, let us remember David was a prophet that foresaw the Christ and interwoven in his reflections on his own life he often predicted details of what was to come during the time of Messiah.
Given all this context of David and his predictions of Messiah, this instance should show us that we should not automatically discount things of similarity between his life as recorded in the scripture and the Messiah's predicted life. The fact that Christ was slaughtered like an animal, his blood shed for our sin, under the hands of his enemies...and yet not one bone broken! does unveil as it were a possible Messianic connection between the word's of David in the Psalm and the life of Messiah. Is it not the ultimate illustration in Christ's death that although the godly must suffer our suffering is under the protection of God and according to his design of salvation? Do we still not suffer in Christ, under his watchful care, as the world pours out its mad venom on every Biblical truth as taught by mocked-at preachers and teachers who have relied on his death for their own salvation though simple bare faith? In conclusion, Christ is 'everywhere' preached in the law and the prophets but it is often very difficult to see him without careful review and consideration.
The intentional obscurity of these shadowy predictions can cause us to doubt their validity on occasions but when combined as a whole and compared to the only person in history that can even remotely be argued as matching them, the evidence is astounding. Jesus was predicted by scriptures. It is a literary miracle that no other book in history has been able to achieve. There are simply too many things, obscurely prefigured, that when compared to the life of Christ became a brilliant light of certainty. The only reason why many Jews were not able to perceive these predictions properly was due to a veil that kept them blind. In contrast the prophets diligently looked into these things and I am sure many other holy men unknown to us, also genuinely looked forward to Christ with the same nature of faith which we have through these weak shadows.
It is also helpful to understand that before Christ died even the Apostles were not capable of connecting all the dots.
He said to them, “This is what I told you while I was still with you: Everything must be fulfilled that is written about me in the Law of Moses, the Prophets and the Psalms.” Then he opened their minds so they could understand the Scriptures. (NIV Luke 24:44-45 )