Potential Complications of Hip Operations

Mr O’Hara does a wide variety of joint preserving hip operations, as well as resurfacings and the occasional complex hip replacement.

This page is a brief summary of the type of complications experienced by patients who have hip surgery. It is not exhaustive and there are a few other relatively rare complications.

Whilst we have listed these potential complications so that you are informed, the risks of each complication occurring is quite small and the overall risk of misadventure following any of these operations is about 2%.

Any operation that involves the hip joint, whether it involves doing a hip resurfacing, a pelvic osteotomy, a femoral osteotomy or any combination of these operations, runs a small risk of sciatic nerve injury. Theoretically a sciatic nerve injury would, at worst, cause permanent numbness and weakness below the knee with a floppy foot with no feeling. In practice, the vast majority of patients have temporary symptoms and enjoy a full recovery or very close to a full recovery. During the course of the recovery sometimes patients with sciatic nerve injuries experience quite distressing pain as the nerve recovers and whilst this is distressing, it is an optimistic feature which suggests that a full recovery, or something close to a full recovery, will be achieved.

There isn’t any treatment available which will hasten the rate of recovery. Symptoms can be helped by the provision of a splint to prevent foot dropping and/or a small halter running across the front of the ankle that achieves the same effect.

Following every operation on the hip where we dislocate the hip, for however short a time, there is a risk of dislocation afterwards. The risk of dislocation varies according to the difficulty of the operation and its complexity. If the hip dislocates it is usually possible to put the hip back in joint afterwards and over the following 6 weeks, provided a special splint is worn, the problem rarely recurs. When in the hospital the nurses and physiotherapists will give you some very specific guidance as to how to avoid or minimise the risk of dislocation but the very occasional dislocation still occurs.

If the hip is successfully put back in to joint and stabilised for the first 6 weeks, it is quite rare for this condition to recur if everything else with the operation has gone well.

In general terms, within the hospital there is a risk of about 1 in 300 of any major operation developing a deep infection. Deep infection is exceedingly rare following pelvic osteotomy and femoral osteotomy and indeed we do not know of any patient who has had a pelvic osteotomy that has developed an infection at the time of the original operation. One or two patients have developed superficial infections following removal of the metalwork and one patient has developed a deep infection following removal of the metalwork.

In the past 3 years there have been 2 deep infections of hip replacements and one of a resurfacing. One of these patients turned out to have diabetes. The patient who had the resurfacing had had 6 previous operations

Superficial wound infections probably occur in 5-10% of the patients that we operate upon and provided they are treated promptly and with appropriate antibiotics, they rarely give rise to any problems. Some of the patients who develop deep infections originally had superficial wound infections and perhaps these weren’t treated as successfully as was needed. If you do develop a superficial infection it is important to consult your GP as soon as it occurs. It will almost certainly recover fully with a 1-2 week course of antibiotics.

Failure of the bones to knit together or the bones knitting together in the wrong postition

Wherever we have cut a bone and realigned the bone in order to normalise the orientation of the hip joint there is a 2% risk of the bones not knitting together. This risk is hugely increased in patients who smoke and we therefore do not do such operations on patients who smoke. If a patient has told us that they have stopped smoking and they have not stopped smoking, they still run a 10-15% risk of the bones not knitting together and that is a heavy price to pay for such deception.

Bone healing is also impaired by taking anti-inflammatory drugs and these including Aspirin, Ibuprofen, Brufen, Naproxen, Voltarol (Diclofenac) and so on. It is important to have good pain relief in the aftermath of the operation for the first few days to a week but thereafter you should only be taking painkillers such as Paracetamol or Paracetamol derivatives - these include Co-codamol, Co-proxamol and Co-dydramol. These are all safe to take and you may need to take 6 or 8 of these every day for the first 6-8 weeks after any operation. There is a small risk – perhaps 1 or 2% - of any bone that we cut and reposition (an osteotomy) knitting together in the wrong position. Since we check the position very carefully during the operation we are confident that the vast majority of patients who suffer a loss of position suffer it due to some failure to follow post-operative instructions. This could include putting too much weight on the leg or putting too much force on it inadvertently during a momentary loss of balance or a jolt. If you suffer such a momentary loss of balance or a jolt and that results in some acute worsening of your post-operative pain, it is important to tell the doctor about this as if a significant change in the bone position has been caused by such an action we may need to readjust the operation and the earlier that this is done the better.

One year about 30% of all the teenagers that we did such operations on between the age of 13 and 18 ruined their operations by ignoring our instructions. If we tell you that your leg is not capable of taking full weight or that you continue to need two crutches, this is for good reason and it is important to follow these instructions; it is too late if the operation has fallen apart and it will be more painful for you, the patient, than for any of us in the hospital.

Complications Related to Hip Replacement and Hip Resurfacing

Following any major operation upon the lower limbs there is a risk of development of a clot in the leg. It has been our routine to give patients an injection of Clexane every day for 3 weeks after their operation in to their belly fat in order to minimise this risk.

I believe that Clexane use has been associated with the deep infections listed above. Accordingly, in line with British Hip Society opinion, I have now changed my nticoagulation to Aspirin 150 mg daily for 3 weeks. (This reduces the complication rate by 30% and the anticoagulation benefit by only 3%).

You will also minimise your risk by being active, bearing appropriate weight regularly on your operated leg as bearing weight on your foot pumps blood back up to your heart. If you do develop minor swelling in your foot it is usually because you are not putting weight regularly enough on your foot to pump the blood back to your heart. All of our operations are designed to allow at least partial weight bearing and a large majority are tolerant of full weight bearing and this is what we expect you to do afterwards. By putting full weight through your leg you pump the blood back up to your heart and you restore the circulation in your leg. The majority of the risk of the development of venous thrombosis is attributable to disuse and failure to maintain this circulation. There is also a small risk that if you develop a thrombosis or clot in your leg then it will move up to your heart and cause a pulmonary embolism. A small proportion of these are fatal but the vast majority of them pass off, however frightening the event is at the time for the patient.

During certain operations upon the hip joint in order to gain access to the diseased part of the hip joint it is necessary to detach some muscles. For instance, at the front of the hip joint it is necessary to detach half of the gluteus minimus and half of the gluteus medius muscles. Although we have done this over 400 times, about a dozen patients have suffered rupture of these muscles and it is likely that this rupture occurred because of over-enthusiasm on the part of the patient.

Such muscles are very tedious to repair a second time. This means that during the first 6 weeks after such an operation if we tell you not to twist your leg inwards or if we tell you not to actively move your leg outwards away from your body, this instruction is critical to the strength and healing of this muscle repair. For the 3% of patients where this complication has occurred it has set back their recovery for 2 or 3 months and this has tended to get them down. Some patients have ruptured their muscle repair as a result of an unguarded movement getting in and out of a shower or a stumbling action and if this does occur it is of cardinal importance to be seen at this hospital as soon as possible so that we can look in to it further.

Important Note

Heavier patients suffer worse, more frequent, more severe and more catastrophic complications than lighter patients do and accordingly you will be doing yourself a major service if you get your weight in order before your operation. As a general guide, if your waist measurement is more than half your height then you are overweight. Being overweight also makes it technically more difficult for the surgeon to do a good job and there is good evidence within the literature to show a measurably higher complication rate in overweight patients.