We conducted a randomised controlled trial to assess the accuracy
of positioning and alignment of the components in total knee arthroplasty
(TKA), comparing those undertaken using standard intramedullary
cutting jigs and those with patient-specific instruments (PSI). There were 64 TKAs in the standard group and 69 in the PSI group. The post-operative hip-knee-ankle (HKA) angle and positioning
was investigated using CT scans. Deviation of >
3° from the planned
position was regarded as an outlier. The operating time, Oxford
Knee Scores (OKS) and Short Form-12 (SF-12) scores were recorded.Aims
Patients and Methods
The piriformis muscle is an important landmark
in the surgical anatomy of the hip, particularly the posterior approach
for total hip replacement (THR). Standard orthopaedic teaching dictates
that the tendon must be cut in to allow adequate access to the superior
part of the acetabulum and the femoral medullary canal. However,
in our experience a routine THR can be performed through a posterior
approach without sacrificing this tendon. We dissected the proximal femora of 15 cadavers in order to clarify
the morphological anatomy of the piriformis tendon. We confirmed
that the tendon attaches on the crest of the greater trochanter,
in a position superior to the trochanteric fossa, away from the
entry point for broaching the intramedullary canal during THR. The
tendon attachment site encompassed the summit and medial aspect
of the greater trochanter as well as a variable attachment to the
fibrous capsule of the hip joint. In addition we dissected seven
cadavers resecting all posterior attachments except the piriformis
muscle and tendon in order to study their relations to the hip joint,
as the joint was flexed. At flexion of 90° the piriformis muscle
lay directly posterior to the hip joint. The piriform fossa is a term used by orthopaedic surgeons to
refer the trochanteric fossa and normally has no relation to the
attachment site of the piriformis tendon. In hip flexion the piriformis
lies directly behind the hip joint and might reasonably be considered
to contribute to the stability of the joint. We conclude that the anatomy of the piriformis muscle is often
inaccurately described in the current surgical literature and terms
are used and interchanged inappropriately. Cite this article:
We undertook a randomised controlled trial to
compare the piriformis-sparing approach with the standard posterior approach
used for total hip replacement (THR). We recruited 100 patients
awaiting THR and randomly allocated them to either the piriformis-sparing
approach or the standard posterior approach. Pre- and post-operative
care programmes and rehabilitation regimes were identical for both
groups. Observers were blinded to the allocation throughout; patients
were blinded until the two-week assessment. Follow-up was at six
weeks, three months, one year and two years. In all 11 patients
died or were lost to follow-up. There was no significant difference between groups for any of
the functional outcomes. However, for patients in the piriformis-sparing
group there was a trend towards a better six-minute walk test at
two weeks and greater patient satisfaction at six weeks. The acetabular
components were less anteverted (p = 0.005) and had a lower mean
inclination angle (p = 0.02) in the piriformis-sparing group. However,
in both groups the mean component positions were within Lewinnek’s
safe zone. Surgeons perceived the piriformis-sparing approach to
be significantly more difficult than the standard approach (p =
0.03), particularly in obese patients. In conclusion, performing THR through a shorter incision involving
sparing piriformis is more difficult and only provides short-term
benefits compared with the standard posterior approach.
We treated 34 patients with recurrent dislocation of the hip with a constrained acetabular component. Roentgen stereophotogrammetric analysis was performed to assess migration of the prosthesis. The mean clinical follow-up was 3.0 years (2.2 to 4.8) and the radiological follow-up was 2.7 years (2.0 to 4.8). At the latest review six patients had died and none was lost to follow-up. There were four acetabular revisions, three for aseptic loosening and one for deep infection. Another acetabular component was radiologically loose with progressive radiolucent lines in all Gruen zones and was awaiting revision. The overall rate of aseptic loosening was 11.8% (4 of 34). Roentgen stereophotogrammetric analysis in the non-revised components confirmed migration of up to 1.06 mm of translation and 2.32° of rotation at 24 months. There was one case of dislocation and dissociation of the component in the same patient. Of the 34 patients, 33 (97.1%) had no further episodes of dislocation. The constrained acetabular component reported in our study was effective in all but one patient with instability of the hip, but the rate of aseptic loosening was higher than has been reported previously and requires further investigation.
We carried out a blinded prospective randomised controlled trial comparing 2-octylcyanoacrylate (OCA), subcuticular suture (monocryl) and skin staples for skin closure following total hip and total knee arthroplasty. We included 102 hip replacements and 85 of the knee. OCA was associated with less wound discharge in the first 24 hours for both the hip and the knee. However, with total knee replacement there was a trend for a more prolonged wound discharge with OCA. With total hip replacement there was no significant difference between the groups for either early or late complications. Closure of the wound with skin staples was significantly faster than with OCA or suture. There was no significant difference in the length of stay in hospital, Hollander wound evaluation score (cosmesis) or patient satisfaction between the groups at six weeks for either hips or knees. We consider that skin staples are the skin closure of choice for both hip and knee replacements.
A total of 455 patients aged over 70 years with a displaced intracapsular fracture of the proximal femur was randomised to be treated either by hemiarthroplasty or internal fixation. The preoperative characteristics of the patients in both groups were similar. Internal fixation has a shorter length of anaesthesia (36 minutes We recommend that displaced intracapsular fractures in the elderly should generally be treated by arthroplasty but that internal fixation may be appropriate for those who are very frail.