Abstract
Introduction: Historically, it has been accepted that the pain associated with arthritis of the hip is usually located in the groin, anterior and lateral thigh with occasional radiation to the anterior knee. Patients complaining of thigh pain that extends below the knee are often considered to have a degenerative lumbar spine as the cause for their lower limb symptoms and total hip replacement (THR) may not be offered.
Following review of data regarding the preoperative distribution of pain in 2000 patients attending for hip replacement, it was noted that 40% of these patients had complained of pain at or below the knee.
We proposed to prospectively investigate the severity and location of pain in patients attending for THR and assessed how this distribution of pain altered following surgery. We also proposed to examine the distribution of radiological wear preoperatively and assess if there is any relationship between localisation of pain, and the severity or distribution of the radiological wear pattern.
Methods: 200 consecutive patients undergoing primary THR completed a questionnaire regarding the location and severity of their pain. Pain was localised to one or more of nine areas extending from low back to the foot. The localisation of pain was quantified as to severity using a visual analogue score. Questionnaires were completed both 4 weeks preoperatively and subsequently at a 3-month review clinic.
All patients underwent a standardised preoperative AP and Lateral x-ray. The AP film was divided into three areas, and the lateral film was divided into 5 areas. Each zone was assessed as to the severity of wear pattern and graded from 1–3 (no change in joint space, decreased joint space, femoral or acetabular destruction).
Results: The 200 patients complained of pain in a total of 980 areas preoperatively and 105 areas postoperative. 70% of the patients had complete relief of all pain at 3 months. The most common area of pain identified by patients was to the anterior aspect of the knee (82%), followed by pain at the greater trochanter and groin. 55% patients complained of pain extending to below the knee, mostly over the anterolateral aspect of the leg. Only 7% of these patients continued to complain of any below knee pain postoperatively, and all of these patients still had some relief of their below knee pain at review.
With regard to the frequencies and severity of x-ray changes, zone-1 (34%) was most commonly severely damaged with femoral and/or acetabular destruction in the AP film, with the anterior and anterolateral areas being most commonly affected areas in the lateral film (20% and 19% respectively).
When the distributions and severities of x-ray changes were correlated with the distribution of pain localised pre and postoperatively we were unable to show any association between the degree of radiological wear in any one zone and the locatin of pain identified by the patient. In fact, there was a normal distribution to the severity of radiological damage between each of the zones and localisation of pain in any of the 9 areas.
Conclusions: A significant number of patients who require hip arthroplasty have pain extending below the knee. This pain is frequently relieved following THR. The commonest area of sever hip joint wear with loss of femoral or acetabular bone is antero-superiorly. It is important to recognise this during surgery, such that action can be taken to ensure appropriate reaming such that subsequent correct tissue tension and leg lengths are achieved. We are unable to show any relationship between area of pain and area of radiological degeneration. We believe that patients who complain of pain in their back, buttock or thigh, which extends below the knee, can still benefit from total hip replacement. Patients who attend complaining of low back pain with radiation of pain down their leg should have their hips as well as their lumbar spine examined and imaged. Careful consideration should be taken before labelling the paid as being referred from degenerative back disease.
The abstracts were prepared by Emer Agnew. Correspondence should be addressed to Irish Orthopaedic Association, Secretariat, c/o Cappagh National Orthopaedic Hospital, Finglas, Dublin 11, Ireland.
