Summary Statement

We present a simple and useful geometrical equation system to carry out the pre-operative planning and intra-operative assessments for total knee arthroplasty. These methods are extremely helpful in severely deformed lower limbs.

Introduction

Total knee arthroplasty (TKA) is associated with significant blood loss, for which blood transfusion might be necessary. The role of the tourniquet is controversial, though it is widely used by orthopedic surgeons. Its use was believed to be effective in decreasing intraoperative blood loss and creating a bloodless surgical field, which theoretically would facilitate the cementing technique and other surgical procedures. However, reactive blood flow reached its peak within five minutes after the tourniquet had been released. The tourniquet controls intraoperative blood loss, but cannot stop postoperative blood loss. Patients who were managed with a tourniquet during the operation often complained of thigh pain. This was possibly caused by the direct pressure of an inflated tourniquet on the nerves and local soft tissues. Limb swelling and increased soft tissue tension caused by reactive hyperperfusion after tourniquet deflation may also contribute to the wound pain. The aim of our study is to investigate the effect of tourniquet on blood loss and soft tissue damage in TKA.

Between April 2004 and July 2007, we performed 241 primary total knee replacements in 204 patients using the e.motion posterior cruciate-retaining, multidirectional mobile-bearing prosthesis. Of these, 100 were carried out using an image-free navigation system, and the remaining 141 with the conventional technique. We conducted a retrospective study from the prospectively collected data of these patients to assess the early results of this new mobile-bearing design.

At a mean follow-up of 49 months (32 to 71), 18 knees (7.5%) had mechanical complications of which 13 required revision. Three of these had a peri-prosthetic fracture, and were removed from the study. The indication for revision in the remaining ten was loosening of the femoral component in two, tibiofemoral dislocation in three, disassociation of the polyethylene liner in four, and a broken polyethyene liner in one. There were eight further mechanically unstable knees which presented with recurrent disassociation of the polyethylene liner. There was no significant difference in the incidence of mechanical instability between the navigation-assisted procedures (8 of 99, 8.1%) and the conventionally implanted knees (10 of 139, 7.2%).

In our view, the relatively high rate of mechanical complications and revision within 30 months precludes the further use of new design of knee replacement.

A retrospective case-control study was performed to examine modifiable medical co-morbidities in patients who develop deep infection after primary total hip or knee replacement. To reduce bias, matching was undertaken using age, gender, and procedure. Co-morbidities were classified by system: cardiovascular, respiratory, gastrointestinal, genitourinary, metabolic, haematological and neurological. Initial analyses demonstrate that patients with infected primary hip or knee replacements are more likely to suffer from medical conditions than patients who did not develop infections. Since many of these co-morbidities are preventable or treatable, early screening and intervention may play a role in reducing prosthetic joint infection.

Deep infection of total hip (THA) and knee replacements (TKA) causes significant patient morbidity and requires considerable health care resources to treat. In order to identify preventable or modifiable medical conditions associated with prosthetic joint infection, a retrospective case-control study was undertaken.

Fifty patients who developed a culture proven deep infection after primary THA or TKA were studied. To reduce bias, a control group of arthroplasty patients was selected using one to one matching based on age, gender, and procedure. Co-morbidities in each group were recorded, and classified by system.

Analysis revealed that patients with joint infections are more likely to suffer from an increased number of co-morbidities than the matched control group. The odds ratios and 95% confidence intervals were determined as: cardiovascular 2.3 (1.0–5.0), respiratory 2.3 (0.8–6.7), gastrointestinal 0.8 (0.4–1.9), genitourinary 3.1 (1.1–8.9), metabolic 1.8 (0.7–4.9), haematological 2.9 (1.1–7.8), neurological 2.9 (0.8–9.9) and diabetes 4.0 (1.2–13.4). The case group had a higher mean BMI than the control group: 33.7 versus 30.9, p=0.00.

Since many of the co-morbidities associated with infection are preventable or readily treatable, early screening and intervention may play a role in reducing the burden of prosthetic joint infection.

A retrospective case-control study was performed to examine modifiable medical co-morbidities in patients who develop deep infection after primary total hip or knee replacement. To reduce bias, matching was undertaken using age, gender, and procedure. Co-morbidities were classified by system: cardiovascular, respiratory, gastrointestinal, genitourinary, metabolic, haematological and neurological. Initial analyses demonstrate that patients with infected primary hip or knee replacements are more likely to suffer from medical conditions than patients who did not develop infections. Since many of these co-morbidities are preventable or treatable, early screening and intervention may play a role in reducing prosthetic joint infection.

Deep infection of total hip (THA) and knee replacements (TKA) causes significant patient morbidity and requires considerable health care resources to treat. In order to identify preventable or modifiable medical conditions associated with prosthetic joint infection, a retrospective case-control study was undertaken.

Fifty patients who developed a culture proven deep infection after primary THA or TKA were studied. To reduce bias, a control group of arthroplasty patients was selected using one to one matching based on age, gender, and procedure. Co-morbidities in each group were recorded, and classified by system.

Analysis revealed that patients with joint infections are more likely to suffer from an increased number of co-morbidities than the matched control group. The odds ratios and 95% confidence intervals were determined as: cardiovascular 2.3 (1.0 – 5.0), respiratory 2.3 (0.8 – 6.7), gastrointestinal 0.8 (0.4–1.9), genitourinary 3.1 (1.1–8.9), metabolic 1.8 (0.7 – 4.9), haematological 2.9 (1.1–7.8), neurological 2.9 (0.8–9.9) and diabetes 4.0 (1.2–13.4). The case group had a higher mean BMI than the control group: 33.7 versus 30.9, p=0.00.

Since many of the co-morbidities associated with infection are preventable or readily treatable, early screening and intervention may play a role in reducing the burden of prosthetic joint infection.

Since September 1999, a total of 45 senile patients with vertebral compression fractures have been randomly selected for this study. Three treatment modalities were performed including the medical treatment only(15; control group), PMMA cement(15; PMMA group) and HA cement(15; HA group) augmentation. The transpedicular injections of PMMA and HA cements were performed on the latter two groups respectively via posterior approach.

For all these patients, the subjective feeling and physical performance were evaluated by questionnaire (Modified Oswestry Questionnaire). The preop and postop X-rays, CT, bone density and bone markers were performed regularly for comparison and analysis.

In general, the subjective feeling and physical performance had at least one grade improvement. Even though the short-term results using questionnaire did not have significant differences among these three groups, many parameters did show the advantages of using cements. The back pain, self-esteem and quality of life resolved much earlier and persistent than that of control group. The non-progression in local kyphosis was also noted in the cement groups.

In addition, there were no significant differences between PMMA and HA cement groups. Both could be regarded as effective and reliable. However, due to the unique biological properties, HA cement is more promising in the future management of osteoporotic fractures.

Distraction osteogenesis (callotasis) has been widely used in patients with limb-length inequality or massive bone defects. This procedure, however, may be associated with a high incidence of physical and psychosocial complications. Callotasis telescoping on a locked intramedullary nail has been used to shorten the period of external fixation. Little attention has been given to the use of locked intramedullary nails in the treatment of complications after callotasis.

Between 1990 and 1999, we used locked intramedullary nailing in 27 patients for the treatment of complications after distraction osteogenesis. There were 17 men and ten women with a mean age of 33.2 years (16 to 66). The nail was inserted at a mean of 3.4 weeks (0 to 15) after removal of the external fixator. Simultaneous autogenous bone grafting and soft-tissue reconstruction were also undertaken in seven and two patients, respectively.

There was consolidation of the callus or docking site in all patients at a mean of 6.4 months (2 to 14) after surgery. The mean shortening of the callus was 0.7 cm (0 to 2.5). Two patients had infection at the site of a distal screw which resolved after removal of the nail. In 17 patients the nail was removed at a mean of 26 months after its insertion.

Locked intramedullary nails are useful in treating complications after distraction osteogenesis in skeletally mature patients. The risk of infection should be borne in mind.

This retrospective study compared the perioperative morbidity of two consecutive groups of patients having primary total knee arthroplasty thru subvastus approach and conventional medial parapatellar approach.

The arthroplasties were performed in consecutive cases of the subvastus group(SV) (21 TKAs in 21 patients) from Dec. 1999 to May 2000 using a subvastus approach and in the control group(CY) of same operator(Y) (26 TKAs in 26 patients) from May 1999 to Nov. 1999 using medial parapatellar approach, and in the second control group(CB) (24 TKAs in 24 patients) from May 1999 to May 2000 using medial parapatellar approach by another operator (L).

The patient perioperative morbidities were evaluated including blood loss, blood transfusion, lateral release, pain condition, time to ROM 90 degrees, skin complication, admission days.

The subvastus group showed less time to gain 90-ROM(6.09, 6.8, 7.85), and less hospitalization days(10.43, 11.3, 12.15). But the SV group also showed higher rate of lateral release(13%, 8%, 12%) and skin complication(9%). Although the difference is not statistically significant.

The authors concluded that the subvastus approach led to early ROM rehabilitation and discharge.

Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two femoral stems have been revised for infection without loosening.

The retrieved acetabular cups were studied by SEM and image-processing techniques to quantify the amount of residual HA on the cup. This was correlated with the clinical variables and modes of failure. The residual HA (as a percentage of the surface) on the loose cups correlated negatively with the duration of implantation (r = −0.732, p < 0.001). Six cups were stable at revision and had more residual HA coating than those which were loose (p < 0.01).

The rate of failure of the Landos Atoll HA-coated, smooth hemispherical cup with screw fixation is unacceptably high. Resorption of the HA coating is markedly increased in loose cups compared with stable cups. HA coating cannot substitute for stable mechanical fixation.