Q: Can I train for a half-marathon after having a hip replacement? I should qualify that by saying the type of hip implant they are recommending is a short-stem. This is supposed to make it possible for me to be more active --  but how active is that, exactly?

A: More than ever before, adults are seeking and receiving hip replacements at a younger age and with the intent of remaining active in recreational and sports activities. The results of a recent study from the University of Munich in Germany may help answer your question.

In their report, this team of surgeons described their success using short-stem hip replacements for adults who were very active before surgery. The majority of patients in this group of patients returned to sports afterwards as well. They didn't mention marathon running but their patients did participate in Nordic walking, hiking, jogging, and other high-impact activities (e.g., handball, soccer, basketball).

Short-stem implants are just as the name implies. The long part of the implant referred to as the "stem" fits down inside the femur (thigh bone). The surgeon reams out bone inside the femur in order to set the stem down inside and stabilize the implant. With a short-stem implant, less bone is removed making it possible to consider revision surgery later if it is needed.

Patients were selected carefully for this study from a group of adults less than 65 years of age and with no hip deformities. The ratio of men to women was 60 per cent men and 40 per cent women. They had to have good bone stock with no sign of osteoporosis (bone thinning or decreased bone density). They were all given the same short-stem implant with a ceramic femoral head using a modified minimally invasive surgical procedure.

The main measure used in this study to report outcomes was sports participation before and after hip replacement. Various measurements were used such as frequency of sports play (how often each week) and duration of participation (number of minutes each session). They also looked at how long it took for each patient to get back to regular and full participation in sports. And the patients rated their pain from zero (no pain) to 10 (worst pain) during the post-operative time period.

Most of the people in the study were able to return to sports participation. But they did tend to gravitate toward lower impact activities, which the surgeons thought was a better idea all around. High-impact activities such as running, jogging, or tennis are not advised by most surgeons.

Patients who engage in these types of activities must be warned of the increased risk of implant failure. However, this study did not support the idea that high-impact activities are necessarily detrimental to the short-stem implant. Patients who progressed slowly from low to high-impact activities and sports were very successful. Overall results were excellent with a high degree of patient satisfaction based on return-to-sports at a level desired by the patients.

Reference: Florian Schmidutz, MD, MSc, et al. Sports Activity After Short-Stem Hip Arthroplasty. In The American Journal of Sports Medicine. February 2012. Vol. 40. No. 2. Pp. 425-432.