Background

Second-generation high-carbon CoCrMo-alloy metal-on-metal total hip arthroplasty (THA) was introduced in the late 1980s following reports of early loosening, impingement, pronounced wear, and hypersensitivity in the first-generation metal-on-metal articulations. There has been inconsistent data that specifically addresses the clinical performance and longevity of second-generation metal-on-metal THA. The purpose of this study was to evaluate the survival of second-generation metal-on-metal primary THA and to assess the influence of demographic factors on implant survival in a large patient cohort.

Introduction: Rotational alignment of the femoral component is widely believed to be crucial for the ultimate success of total knee arthroplasty (TKA). However there is a paucity of normative data on femoral component rotation in ‘perfect’ TKA.

Methods: Femoral component rotation in well-functioning TKA was assessed by means of axial radiography as described by Kanekasu et al. Well-functioning TKA were defined by three criteria at 5-year follow-up:

Knee Society objective and functional score of 190 or above

Thirty TKA of 29 patients (9 male, 20 female) with a median age of 70 years (range, 31–87) at time of surgery fulfilled the study criteria. All TKA were implanted at a single high-volume joint replacement center in 2002. In all cases both the condylar twist angle (CTA) using the clinical epicondylar axis (CEA) and the posterior condylar angle (PCA) using the surgical epicondylar axis (SEA) were used to assess rotational alignment of the femoral component.

Results: Overall, the mean CTA was 3.6+−3.5° of internal rotation (IR) (range, 4.1° of external rotation (ER) to 8.6° of IR) for the femoral component. For females, the CTA had a mean value of 4 +/−3.7° of IR (range, 7.6° of IR to 4.1° of ER) compared to 2.3 +/−3° of IR (range, 5.3° of IR to 2.5° of ER) in males. Overall, the mean PCA was 1.5 +/−3.5° of ER (range, 8.4° of ER to 5.1° of IR). In females, the mean PCA was 1 +/−3.9° ER (range, 2.3° of IR to 5.8° of ER) compared to 2.8 +/−2° ER (range, 0.4° of ER to 5.7° of ER) in males. The mean angle between CEA and SEA was overall 5.1 +/−1.8° (range, 3.3° to 9.1°), in females 5.1 +/−1.6° (range, 3.5° to 9.0°) compared to 5.0 +/−2.4° (range, 3.2° to 9.1°) in males.

Conclusion: Well-functioning TKA demonstrated a highly variable rotational alignment of the femoral component ranging from excessive external rotation to excessive internal rotation. These findings challenge current reference values for optimal femoral component rotation.

Introduction: Stiffness after primary total knee arthroplasty (TKA) is a severe complication that has been associated with excessive internal rotation of the femoral component.

Methods: Between 2001 and 2004, 18 patients with 18 well-fixed, aseptic primary TKA underwent revision TKA at a single high-volume joint replacement center for stiffness in the presence of femoral component mal-rotation. Stiffness was defined as ROM with less than 90° of maximum flexion or a flexion contracture greater than 10°. Femoral component malrotation was defined as a condylar twist angle of more than 4° of internal rotation using CT scans. Following IRB approval, 17 out of 18 patients (median age at time of the index surgery 62.7 years, range 45 to 78; female, n=11; male, n=6) were available for retrospective outcome assessment. The mean time between primary and revision TKA was 3.2 years (range, 9–79 months). At a mean follow-up of 3.3 years (range, 2 to 6), all patients were evaluated clinically using the Knee Society objective and functional scores, and by CT measurement of femoral component rotation. Patients without additional procedures between primary and index revision TKA (group A, n=9) were compared using Student t-testing with those which had undergone additional interventions (group B, n=8).

Results: Five patients had required additional procedures after the index revision TKA including closed manipulation under anesthesia in one case, patellar resurfacing in one case, metal removal after tubercle osteotomy and open debridement in another case, and tibial component revision followed by revision TKA in one case. CT scans after revision TKA revealed correction of femoral component rotation in all but one case from each group. After revision TKA, the mean objective score was overall 73 points, in group A 82 points compared to 63 points in group B (p< 0.001). In group A there were 78% excellent or good results compared to 13% in group B. The mean function score was overall 74 points, 78 points in group A compared to 69 points in group B. There were 67% good or excellent results in group A compared to 12% in group B. Mean flex-ion increased overall from 71 to 92 degrees (p< 0.01), in group A from 61 to 96 degrees (p< 0.01) and in group B from 82 to 89 degrees. Mean flexion contracture was reduced overall from 7 to 4 degrees, in group A from 6 to 3 degrees, and in group B from 8 to 5 degrees. Stiffness persisted in four cases (24%) (group A, n=1; group B, n=3). Satisfaction (VAS 0–100; 100=completely satis-fied) scored overall a mean of 52 points, in group A 57 points and in group B 44 points.

Conclusion: Overall, revision TKA for knee stiffness associated with femoral component internal malrotation resulted in significantly improved knee motion. However, outcome was less predictable in those patients with additional procedures between primary and revision TKA.

We investigated the clinical and radiological outcome after unilateral fracture of the lateral process of the talus in 23 snowboarders with a mean follow-up of 3.5 years (12 to 76 months). In this consecutive cohort study both operative and non-operative cases were considered.

The mean American Orthopaedic Foot and Ankle Society hindfoot score was 94 (82 to 100). The non-operative group of seven with a minimally-displaced fracture scored higher (98 points) than the operative group of 16 with displaced or unstable fractures (93 points). In 88% of operative cases, significant concomitant hindfoot injuries were found at operation. All but eight (35%) patients (six operative and two non-operative) regained their pre-injury level of sporting activity. Subtalar osteoarthritis was present in nine (45%) of the 20 patients available for radiological review, including one late-diagnosed non-operative case and eight operative cases with associated injuries or fracture comminution.

The outcome after fracture of the lateral process of the talus in snowboarders is favourable provided an early diagnosis is made and adequate treatment, which is related to the degree of displacement and associated injuries, is undertaken.

We investigated the clinical and radiological outcome of trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia in 38 consecutive patients (45 knees) with a mean follow-up of 8.3 years (4 to 14).

None had recurrence of dislocation after trochleaplasty. Post-operatively, patellofemoral pain, present pre-operatively in only 35 knees, became worse in 15 (33.4%), remained unchanged in four (8.8%) and improved in 22 (49%). Four knees which had no pain pre-operatively (8.8%) continued to have no pain.

A total of 33 knees were available for radiological assessment. Post-operatively, all but two knees (93.9%) had correction of trochlear dysplasia radiologically but degenerative changes of the patellofemoral joint developed in 30% (10) of the knees.

We conclude that recurrent patellar dislocation associated with trochlear dysplasia can be treated successfully by trochleaplasty, but the impact on patellofemoral pain and the development of patellofemoral osteoarthritis is less predictable. Overall, subjective patient satisfaction with restored patellofemoral stability after trochleaplasty appeared to outweigh its possible sequelae.

Introduction and Aims: Hip arthroplasty alters stress patterns in the proximal femur, thereby influencing femoral bone remodelling. The purpose of our study was to determine long-term skeletal response to wellfixed total hip arthroplasty.

Method: Seventy-two hips in 66 patients (mean age 57, range 25–72; 29 male, 37 female) were evaluated with standardised measurement protocol after arthroplasty with cemented Charnley (32 hips) or uncemented 5/8 coated AML stem (40 hips). Inclusion criteria: stable implants and complete radiographic record with minimum follow-up 15–20 years. 3159 measurements were made with power calipers and normalised for magnification.

Results: There was time dependent loss of proximal cortical thickness around both stems (AML greater than Charnley; proximal medial greater than proximal lateral cortex, (p< 0.05, all parameters). At 15–20 years, median proximal medial cortical thickness decreased by 12% for Charnley and 70% for AML stems. Median proximal lateral cortical thickness decreased by 9% for Charnley and 21% for AML stems. Median cortical thickness changes around the mid and distal prosthesis for both stems was mild, with a non-statistically significant trend (p> 0.05) towards more cortical loss (2–9%) around Charnley than AML stems (0–8%). The median intramedullary width increased by 1–10%, depending on level (no difference by prosthesis type, p> 0.05). Changes continued progressively over the entire observation period.

Conclusion: This paper provides the first detailed long-term information on the effect of well-functioning hip arthroplasty on femoral morphology in a large patient group. Morphologic changes are most pronounced in the proximal medial femur and vary by implant type. Also, the medullary canal widens around a replaced hip as the patient ages.

A six-year-old girl with congenital sensory neuropathy with anhidrosis (CSNA) presented with bilateral hip dysplasia and subluxation on the right side.

Conservative treatment of the hips by closed reduction and a plaster cast was unsuccessful. When aged seven years the patient had an intertrochanteric varus rotation osteotomy on the right side, but subluxation was again evident after five months. A Salter-type pelvic osteotomy was carried out followed by immobilisation, but one year later subluxation was present in the right hip and dislocation in the left. At the age of nine years, the right femoral head resembled a Charcot joint, although walking ability was preserved.

In patients with CSNA, surgery may not always be advisable.