Introduction & aims

Satisfaction following total knee replacement (TKR) surgery remains suboptimal at around 80%. Prediction of factors influencing satisfaction may help manage expectations and thus improve satisfaction. We investigated preoperative variables that estimate the probability of achieving a successful surgical outcome following TKR in several outcomes important to patients.

Introduction

The risk of hip dislocation after revision total hip arthroplasty is up to 20% following surgery for periprosthetic fractures. A technique was developed by the senior authors, involving a transtrochanteric osteotomy and superior capsulotomy to attempt to minimise this risk(1).

We identified 26 tibial tubercle osteotomies (TTOs) performed in 23 revision knee arthroplasties between 2009 and 2013. Average age at last operation was 66 (33–92). Mean follow-up period was 14 months (3–33).

Eleven TTOs were performed in 10 knees for single stage revisions and 15 TTOs were performed in 13 knees for 2 stage revisions in the setting of deep infection. In this infected subset 11 patients had a TTO performed at the first stage. This osteotomy was left unfixed to avoid leaving metalwork in a potentially contaminated wound, reopened, and then definitively secured with screws at the second stage. Our technique involves fashioning a long 7×1cm tibial tuberosity osteotomy without a proximal step-cut.

All osteotomies united with no fractures. Minor proximal migration was noted in one case associated with screw loosening. There was no proximal migration noted in the 2 stage cases where the osteotomy had been left initially unfixed. There were no extensor lags.

We conclude that TTO is a safe and reproducible procedure when adequate exposure cannot be obtained in revision knee arthroplasty. In 2 stage revisions sequential osteotomies does not decrease union rates and leaving the osteotomy unfixed after the first stage does not cause any issues.

Eligible patients were randomly allocated to PMI or standard intramedullary jigs. Smith and Nephew's patient specific cutting blocks (Visionaire) were used for PMI. Postoperative component positioning was investigated using the ‘Perth CT protocol’. Deviation of more than 3° from the recommended position was regarded as an outlier. Exact Mann-Whitney U test was used to compare component positioning and difference in proportion of outliers was calculated using Chi Squared analysis.

Fifty-five knees were enrolled in the standard instrumentation group and fifty-two knees in the PMI group.

Coronal femoral alignment was 0.7 ± 1.9° (standard) vs 0.5 ± 1.6° (PMI) (P=0.33). Outliers 9.4% vs 7.4% (P=0.71). Coronal tibial alignment was 0.4 ± 1.5° (standard) vs 0.6 ± 1.4° (PMI) (P=0.56). Outliers 1.9% vs 1.9% (P=0.99). Sagittal femoral alignment was 0.6 ± 1.5° (standard) vs 1.3 ± 1.9° (PMI) (P=0.07). Outliers 3.8% vs 13.2% (P=0.09). Tibial slope was 1.7 ± 1.9 ° (standard) vs 1.8 ± 2.7° (PMI) (P=0.88). Outliers 13.2% vs 24.1% (P=0.15). External rotation of femoral component was 0.6 ± 1.4° (standard) vs 0.2 ± 1.8° (PMI) (P=0.14). Outliers: 3.8% vs 5.6% (P=0.66).

Compared to standard intramedullary jigs, patient matched instrumentation does not improve component positioning or reduce alignment outliers.

Summary: This study of 1000 patients demonstrates how you can dramatically reduce hospital length of stay, improve clinical outcomes, and increase patient satisfaction if a patient-centred pathway approach is adopted.

Introduction: This study evaluates the effect of adopting a patient-centred approach on clinical outcomes, patient satisfaction and operational efficiency. By adopting standardised working practices, dramatic changes can be achieved to reduce patient length of stay (LOS) and consequently surgical capacity.

Methods: We prospectively studied the first 1000 patients who followed the new pathway (549 Total Knee Replacements, 20 Unicondylar Knee Replacements, 384 Total Hip Replacements and 47 Hip resurfacings). The pathway included an enhanced pre-assessment process. Admission dates were mutually agreed and a predicted discharge date of 4 days was provided. All patients attended a pre-operative education session. Patients were admitted on the day of surgery and followed an intensive physiotherapy program. The surgeons, surgical techniques, and discharge criteria all remained unchanged.

Results: The average length of stay was 4.1 days (St Dev 1.8). 80% of patients went home on or before day 4 post-operatively. This was accompanied by a decreased re-admission rate (1.8%), low complication rates for both hip replacement (Dislocation rate = 0.93%) and knee replacement (Knee MUA = 0.87%) and no cases of deep infection. Pre-operative patient reported outcome measures (WOMAC, SF-12 and Oxford) all improved post-operatively (P< 0.0001) and qualitative data from patients was extremely positive towards the new pathway.

Discussion: The decrease in LOS was dramatic and highly clinically significant. The mean LOS for patients prior to commencing this new pathway was 7.5 days (St Dev 5.7). High patient satisfaction rates indicate that by adopting a patient-centred approach, significant decreases to LOS can be achieved alongside improving the quality of care with a low complication and readmission rate.

Introduction Primary and revision total hip surgery in the face of poor neuromuscular function, cognitive impairment or recurrent dislocation are fraught with complications. A useful option for such cases is the constrained acetabular component, or “captive cup”. We present the largest series reported to date, and use radiostereometric analysis (RSA) to assess cup migration.

Method Between February 1999 and September 2003 133 patients (141 hips) were identified as high risk of dislocation and were treated with a constrained acetabular component. One hundred and twenty cases were revision arthroplasties and 21 were primary replacements. Patients were assessed pre-operatively (WOMAC, Harris Hip Scores and SF-36). Defects were reconstructed with allograft (massive, morsellised or strut) where required. Most components were inserted into uncemented metal cups. Radiostereometric beads were inserted. Post-operatively patients were followed up regularly and clinical scores repeated. Radiostereometric analysis (RSA) was performed at 6 months, and then annually to assess prosthesis migration.

Results Mean follow-up was 3.1 years (range 1 – 5.6 years). At last review 26 patients had died, and 7 were lost to follow-up. There were 8 revisions for cup loosening. There were 5 dislocations and 2 dissociations in 6 patients. There was a statistically significant improvement in WOMAC and Harris Hip scores. RSA confirmed cup migration was greater than for non-captive cups, but was nevertheless minimal. Interestingly there was no statistically significant difference at 6, 12 and 24 months suggesting most migration occurs early on.

Conclusion Our results suggest the “captive cup” is an effective and safe option for the treatment of primary and revision arthroplasty in those at high risk of dislocation.

Introduction and aim: Early symptomatic osteoarthritis (OA) of the knee poses a difficult challenge to orthopaedic surgeons, particularly in the presence of malalignment. Most surgical options are palliative. Our aim was to assess combined high tibial osteotomy (HTO) and matrix-induced autologous chondrocyte implantation (MACI) as a curative option.

Methods Patients with localised medial compartment OA and varus malalignment were identified. Suitability for the above procedure was confirmed at arthroscopy and specimen taken for culture. HTO and MACI procedures were performed in one sitting by a single surgeon. Patients received three months rehabilitation and function was assessed preoperatively and at three-monthly intervals.

Results Twelve patients were identified: nine male; average age 46 years (27–58). Mean varus deformity was 6 degrees. Two patients also had evidence of osteochondritis dissecans, and two early patello-femoral OA. Eight patients had had previous surgery to the knee.

Eleven patients had a lateral closing wedge osteotomy; the medial opening wedge was performed in a case of leg shortening. Mean operation duration was 72 minutes (60–90). The graft was fixed with fibrin glue in all cases, and augmented with stitches or vicryl pins in five cases. Mean defect size was 6.2cm2 (2–12). There were three complications: one DVT, a haemarthrosis and a graft detachment.

Average follow-up was 16 months. MRI scans at three months show oedematous tissue at the defect sites, contrasting with the fluid filled defects seen preoperatively. Scans at one-year show hyaline-like cartilage infill with similar signal characteristics to native hyaline cartilage. Six minute walk test and knee injury and osteoarthritis outcome score indicate significantly improved functional capacity at six months and one year.

Conclusions Preliminary results suggest combined HTO and MACI is successful for young patients with early OA associated with malalignment.

Introduction: Primary and revision total hip surgery in the face of poor neuromuscular function, cognitive impairment or recurrent dislocation are fraught with complications. A useful option for such cases is the constrained acetabular component, or “captive cup”. We present the largest series reported to date, and use radiostereometric analysis (RSA) to assess cup migration.

Method: Between February 1999 and September 2003 126 patients were identified as high risk of dislocation and were treated with a constrained acetabular component. One hundred and sixteen cases were revision arthroplasties and 10 were primary replacements. Patients were assessed pre-operatively (WOMAC, Harris Hip Scores and SF-36). Defects were reconstructed with allograft (massive, morsellised or strut) where required. All components were inserted into uncemented metal cups. Radiostereometric beads were inserted. Post-operatively patients were followed up regularly and clinical scores repeated. Radiostereometric analysis (RSA) was performed at 6 months, and then annually to assess prosthesis migration.

Results: Mean follow-up was 3.1 years (range 1 – 5.6 years). At last review 8 patients had died, and 2 were lost to follow-up. There were 7 revisions: 3 for infection, 2 for periprosthetic fractures, and 2 for aseptic loosening. There was one case of cup disassociation successfully treated with open reduction. There have been no further dislocations. There was a statistically significant improvement in WOMAC and Harris Hip scores. RSA confirmed cup migration was greater than for non-captive cups, but was nevertheless acceptable: 0.16mm medially, 0.47mm proximally, 0.16mm posteriorly. Interestingly there was no statistically significant difference at 6, 12 and 24 months suggesting most migration occurs early on.

Conclusion: Our results suggest the “captive cup” is an effective and safe option for the treatment of primary and revision arthroplasty in those at high risk of dislocation. RSA analysis confirms minimal prosthesis migration.

Introduction: Iontophoresis is a method to introduce antibiotic molecules into allograft bone using an electrical potential; the antibiotics may then be released at therapeutic levels for extended periods of time. This is the first report of iontophoresed allograft implantation into patients.

Method: A method of loading tubular sections of cortical bone was used in theatre prior to implantation. Postoperative serum, drain and allograft antibiotic assays were performed. Patients were followed-up clinically and radiologically. All patients who received a bulk segmental allograft from June 1997 were entered into the trial.

Results: Since June 1997, 35 patients have received 37 allografts. Indications for allograft insertion were limb salvage for tumour (18), and poor bone stock associated with infection (11), periprosthetic fracture (6), aseptic loosening (1) and recurrent dislocation of total hip replacement (1). Mean follow-up is 3.3 years, and no patients have been lost to follow-up. One patient received two allografts in different sites and one had an allograft exchange. There has been one superficial wound infection and one deep infection. The latter patient was revised to another iontophoresed allograft and has had no recurrence at 34 months. One allograft has been revised to a vascularised fibular graft and allograft exchange following fracture of metal fixation. There was one case of persistent non-union in a knee arthrodesis which was treated after 21 months by removal of the intramedullary fixation and use of an Illizarov frame. The allograft was not revised. All other allografts are in situ with no complications related to the allograft. Eleven patients had pre-existing proven infections. None of these patients have been re-infected to date. Therapeutic gentamicin and flucloxacillin levels were detected in drain fluid samples post-operatively.

Conclusions: Iontophoresis is a safe and inexpensive technique that delivers high local dose of antibiotic, which may reduce infection in avascular allograft bone.

Introduction: Acute compartment syndrome is most commonly seen in the lower limb. Only four cases have been reported in the paraspinal muscles. The common features of this condition have not been described.

Methods: Following the successful surgical treatment of a case of bilateral paraspinal muscle compartment syndrome, a thorough search was made of all similar cases in Medline, and by hand-searching of references lists.

Results: Only four other cases of non-traumatic paraspinal compartment syndrome were identified in the literature. Closer analysis revealed many features in common with our case. The condition tends to occur in skiers in their 20s with a previous history of exercise-induced back pain. Patients present with paraspinal muscle spasm and loss of sensation of the loin, after a few days of heavy exertion. There is abdominal tenderness and bowel sounds are reduced. Consistent findings on blood chemistry are marked elevation of creatinine kinase, myoglobin and LDH. There is an associated myoglobinuria. MRI is helpful in identifying extent of muscle involvement and guiding surgical intervention. The most useful investigation is the direct measurement of compartment pressures. Treatment can be operative or non-operative, although surgery is associated with more rapid recovery and elimination of pain.

Discussion and Conclusion: The common features of acute paraspinal compartment syndrome of non-traumatic origin have not previously been recognised. We have helped define the characteristics of this condition to aid earlier recognition and treatment.

Introduction: Treatment for ruptured Achilles tendon can be classified into operative (open or percutaneous) and non-operative (cast immobilisation or functional bracing); post-operative splintage can be with a rigid cast or functional brace. The aim was to identify and summarise the evidence from randomised trials of the effectiveness of different interventions.

Methods: We searched the Cochrane specialised register, MEDLINE, reference lists of articles and contacted trialists directly for all randomised and quasiran-domised trials comparing different treatment regimes for acute Achilles tendon ruptures.

Results: Fourteen trials involving 891 patients were included.

Open operative treatment compared with non-operative treatment was associated with a lower risk of re-rupture (odds ratio (OR) = 0.25, 95% confidence interval (CI) = 0.1–0.6, p=0.003) but a higher risk of other complications including infection, adhesions and disturbed sensibility (OR = 14.1, 95%CI = 6.3–31.7, p< 0.00001).

Open versus percutaneous operative surgical repair was associated with a longer operation duration and higher risk of infection (OR = 12.9, 95%CI = 1.6–105.6, p=0.02).

Patients splinted with a functional brace rather than a cast post-operatively tended to have a shorter in-patient stay, less time off work, quicker return to sporting activities and fewer reported complications (p=0.0003).

Because of the small number of patients involved no definitive conclusions could be made regarding different operative techniques and different non-operative regimes.

Conclusions: Open operative treatment significantly reduces the risk of re-rupture but has the drawback of a significantly higher risk of other complications, including wound infection. The latter may be reduced by performing surgery percutaneously. Post-operative splintage in a functional brace appears to reduce hospital stay and time off work and sports.

Introduction We believe minimally invasive surgery should be defined by the extent of soft tissue dissection rather than incision length. We describe a new technique that is truly soft-tissue sparing and report our early results.

The surgical approach The landmarks for the incision are identified and a 6–8cm oblique incision is made over the posterior aspect of the greater trochanter. Longer incisions are required in more difficult cases. Piriformis and the proximal insertion of gluteus maximus are preserved. After implant insertion, meticulous capsular repair is performed through drill holes into bone to reconstruct the posterior envelope. There are no restrictions to mobility. No specialised instruments are required.

Method The standard posterior approach (group 1) was compared with the PSMI approach (group 2) in a prospective cohort study of 200 consecutive patients over 60 years of age. In the standard approach the external rrotators were dettached. The capsule was repaired to bone, and the piriformis tendon reattached to the Gluteus Medius tendon. Routine restrictions to mobility were imposed. Patients were scored pre-operatively and followed up prospectively, by a blinded observer.

Results Demographics and functional scores were similar. Mean operation time was about 1 hour in both groups. Mean incision length was 21.5 cm (range 15 – 25) in group 1 and 8.4 cm (range 6 – 16) in group 2. Mean blood loss in group 1 was significantly higher than group 2 (P< 0.0001, 95%CI 191–547). Mean inpatient stay was 8.0 days in group 1, and 4.8 days in group 2 (P< 0.0001, 95%CI 3.4–6.0).

Minimum follow-up was 3 years in group 1 and 1.5 years in group 2. There were 3 dislocations in group 1, and none in group 2. There were 2 re-operations in both groups. The relative improvement in WOMAC scores was significantly greater in group 2 at 3 months and 1 year (P< 0.05).

Conclusion The PSMI approach to the hip is truly soft-tissue sparing. It is safe and relatively easy to perform. The stability and minimal morbidity allow early mobilisation. This is the first study to suggest the benefits of minimally invasive surgery may be prolonged. Cosmesis is a by-product rather than primary objective.

Introduction and Aims: A number of ‘minimally invasive’ approaches have been described which are essentially a standard approach through a smaller incision: the term ‘mini-incision’ is more appropriate. We describe a new technique that is truly soft-tissue sparing and report our early results.

Method: Following Malchau’s principles we performed cadaver studies to familiarise ourselves with the approach before conducting a pilot study. The approach involves a 6–8cm oblique incision over the posterior aspect of the greater trochanter. Care is taken to preserve piriformis and gluteus maximus. Meticulous capsular repair is performed through drill holes into bone at the end of the procedure to reconstruct the posterior envelope. There are no restrictions to mobility post-op.

Patients were scored pre-operatively and followed up prospectively. The only special instruments required are two large curved Hohmann retractors and an angled cup introducer.

Results: One hundred and one consecutive routine primary total hip replacements were performed via the ‘piriformis-sparing minimally invasive approach’ by a single surgeon. Marked on-table stability was noted in all hips prior to capsular repair.

Forty-two percent of patients were male. Mean age was 68.9 years (42–90) and BMI 26 (14–39). Average operation time was 64.1 minutes and anaesthetic time 92.5 minutes. Mean fall in haemoglobin in the first 24 hours was 2.3g/dl. Mean incision length was 7.4cm.

Follow-up was a minimum of one year (range 12–29 months). There was a highly statistically significant improvement in WOMAC and SF-36 scores at three and 12 months post-operatively (p< 0.0001). Early medical complications occurred in 12 patients, including two superficial infections, all of which resolved. There were no peri-prosthetic fractures and importantly, no dislocations. There were two re-operations: one revision for cup displacement and one washout for deep infection.

Conclusion: We believe that the marked stability that we achieve on-table is only possible by sparing piriformis and careful capsular repair. As with all new procedures however, there is a learning curve for both surgeon and assistant. Preliminary results from our pilot study may be interpreted with guarded optimism.

Introduction and Aims: The Lateral Femoral Cutaneous Nerve is placed at risk of iatrogenic injury in the dual incision minimally invasive approach THA. A number of trials have indicated rates of injury up to 30%. This clinical and cadaver study examined the morphology of the nerve in 101 cadaver specimens and in 78 dual incision THA patients.

Method: One hundred and one lateral femoral cutaneous nerves of the thigh were dissected in fresh and formalin embalmed specimens. Dissection was limited to the anterior thigh and the branch pattern of the LFCN recorded. Dual incision patients were followed prospectively and examined with regard to LFCN paraesthesia.

Results: Despite the variability of the nerve, three basic morphologic patterns emerged. Approximately 55% had a major medial trunk and smaller lateral branch, 30% involved two distinct large branches and 15% had a trifurcation or other pattern.

In our clinical series, over 30% of patients experienced paraesthesia and some experienced a burning dysaesthesia in the distribution of the LFCN.

Conclusion: Iatrogenic injury to the LFCN is relatively common in the dual incision minimally invasive THA and patients must be informed of such a risk. Based on this study we have slightly modified our incision and approach.

Introduction and Aims: The use of ‘superglue’ (2-Octylcyanoacrylate) in wound closure is well established in other surgical specialties, but not described in orthopaedics. The aim was to compare superglue with staples and subcuticular suture in a prospective randomised trial.

Method: One hundred and fifty patients admitted for a primary total knee or hip replacement were randomised to receive either clips, continuous subcuticular suture (3.0 Monocryl) or ‘superglue’ for wound closure. All knee replacements were mobilised on the day of surgery with CPM and hip replacements on the first post-operative day. Patients’ wounds were assessed on day one and at six weeks by a blinded observer.

Results: There were 80 hips and 70 total knee replacements performed; 51 wounds were closed with clips, 50 with suture and 49 with superglue. Mean duration of skin closure was significantly shorter with staples, and superglue was significantly faster than suture. There was no significant difference in the complication rates between the groups, including infection, dehiscence or allergic reaction. There was significantly more ooze by day one from the wounds closed with clips than the other two groups. Significantly more of the wounds closed with glue had no strike-through on to the dressing, and were therefore deemed to be ‘sealed’. Patient satisfaction at six weeks was significantly higher with superglue and suture than staples. The suture and super-glue groups had higher median scores on the Hollander wound evaluation scale than staples, however the difference was not statistically significant. Surgeon satisfaction with technique was highest with superglue and staples (no significant difference between the groups), and significantly higher than with subcuticular suture.

Conclusion: Superglue is safe to use for skin closure in primary knee and hip arthroplasty. Although closure with staples is faster, superglue is associated with less wound ooze and better patient satisfaction. The cosmetic result with superglue is comparable to that of subcuticular sutures but has a better surgeon satisfaction score.

Introduction THR is a successful procedure with excellent long term results. With many patients requiring the procedure there is some advantage in rapid recovery and early discharge. This may require a change in the surgical approach and peri-operative management. We report the first series of a new minimally invasive surgical approach for THR.

Methods A two incision approach for THR has been developed after extensive cadaver tests. This consists of an anterior muscle splitting incision to insert the cup and a posterior incision for the stem insertion. The authors have undergone cadaver training and clinical surgery before embarking on clinical trials. Patients included in this study are those people awaiting THR who were selected for a cementless prothesis and who would benefit from early rehabilitation. Patients with previous surgery, hip dysplasia and significant obesity were excluded. An initial study group are presented with an average age of 59, average height 168 cms and average weight 71 kg.

Results Average length of stay was 3.7 days with an average operative time of 90 minutes. Average blood loss 505 mls with an average blood usage of 1.1 units. Early complications include lateral cutaneous nerve of thigh palsy (50% resolution at three months), two stable trochanter fractures, one infection and one anterior dislocation at eight weeks with a ceramic implant.

Conclusions The approach is technically difficult and initially time consuming. It does enable quicker mobilisation and appears to result in less need for analgesia post-operatively. We believe it is important to present the early results so the technique can be discussed and potential problems avoided. A randomised, prospective trial with clinical and RSA follow-up is underway.

Introduction Impaction grafting in revision hip arthroplasty has now been used with a number of cemented stem designs. Follow-up has been short/intermediate with variable results due to pronounced stem subsidence and incomplete cement mantles. This study investigated the performance of a cementless, HA-coated stem used with the impaction grafting technique.

Methods We performed revision hip arthroplasty on a series of 16 stems for mechanical loosening (majority type II) in 14 patients (mean age 64 years). An uncemented Anatomic® stem was inserted into a neomedullary canal of impacted fresh frozen allograft bone. Stem migration was assessed with RSA. Graft and host cortical bone remodeling were evaluated radiographically as was the quality of the impaction grafting and amount of radiographic bone ingrowth. Bone mineral density (BMD) was assessed with DEXA at two and 10 years. Harris Hip Score was recorded for clinical assessment.

Results At six months the stems had subsided 0.78 mm (−7.78 – 0.22). Thereafter, the majority stabilized (6 months vs. 12 years: p=0.3). The graft had a homogenous distribution proximally, but to a lesser extent distally. Remodeling of graft was frequently seen at two years, especially proximally. There were no signs of graft resorption and no change in BMD in any Gruen zone between two and 10 years (P=0.15 – 0.54). About one third of patients had evidence of cortical restitution. In most cases there were no radiolucencies at all between the HA-fiber mesh and the bone. Slight cortical erosion at the stem tip was observed in nine cases but none progressed after two years. These parameters (remodeling, ingrowth and radiolucencies) changed minimally between the two and 12 years. At two years, the Harris Hip (50 to 85) and pain scores (20 to 40) had increased (p = 0.001). Thereafter the scores remained stationary. One hip dislocated during the first year. Heterotopic ossification occurred in three cases. One case underwent two stage revision at 30 months for late infection. One fracture was detected post-operatively. This stem subsided 16.2 mm at two years requiring revision. One patient died due to unrelated causes. Early migration was seen. Radiographs suggest much of the graft was substituted with living bone with no deterioration between two and 12 years.

Conclusions Our findings are sufficiently encouraging to initiate trials of uncemented stems with extended HA coatings.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.